A probabilistic maintenance model for diesel engines

NASA Astrophysics Data System (ADS)

Pathirana, Shan; Abeygunawardane, Saranga Kumudu

2018-02-01

In this paper, a probabilistic maintenance model is developed for inspection based preventive maintenance of diesel engines based on the practical model concepts discussed in the literature. Developed model is solved using real data obtained from inspection and maintenance histories of diesel engines and experts' views. Reliability indices and costs were calculated for the present maintenance policy of diesel engines. A sensitivity analysis is conducted to observe the effect of inspection based preventive maintenance on the life cycle cost of diesel engines.

Dynamic Cost Risk Assessment for Controlling the Cost of Naval Vessels

DTIC Science & Technology

2008-04-23

for each individual RRA at the start of the project are depicted in Figures 2a and 2b, respectively. The PDFs are multimodal and cannot be...underestimates cost. 7 Probabilistic cost analysis A physician metaphor Adapted from Yacov Y. Haimes, NPS 2007 8 Dynamic cost risk management A physician... metaphor Adapted from Yacov Y. Haimes, NPS 2007 9 Sources of cost uncertainty Macroscopic analysis Economic, Materials & Labor, Learning rates

Economic Evaluation of Pediatric Telemedicine Consultations to Rural Emergency Departments.

PubMed

Yang, Nikki H; Dharmar, Madan; Yoo, Byung-Kwang; Leigh, J Paul; Kuppermann, Nathan; Romano, Patrick S; Nesbitt, Thomas S; Marcin, James P

2015-08-01

Comprehensive economic evaluations have not been conducted on telemedicine consultations to children in rural emergency departments (EDs). We conducted an economic evaluation to estimate the cost, effectiveness, and return on investment (ROI) of telemedicine consultations provided to health care providers of acutely ill and injured children in rural EDs compared with telephone consultations from a health care payer prospective. We built a decision model with parameters from primary programmatic data, national data, and the literature. We performed a base-case cost-effectiveness analysis (CEA), a probabilistic CEA with Monte Carlo simulation, and ROI estimation when CEA suggested cost-saving. The CEA was based on program effectiveness, derived from transfer decisions following telemedicine and telephone consultations. The average cost for a telemedicine consultation was $3641 per child/ED/year in 2013 US dollars. Telemedicine consultations resulted in 31% fewer patient transfers compared with telephone consultations and a cost reduction of $4662 per child/ED/year. Our probabilistic CEA demonstrated telemedicine consultations were less costly than telephone consultations in 57% of simulation iterations. The ROI was calculated to be 1.28 ($4662/$3641) from the base-case analysis and estimated to be 1.96 from the probabilistic analysis, suggesting a $1.96 return for each dollar invested in telemedicine. Treating 10 acutely ill and injured children at each rural ED with telemedicine resulted in an annual cost-savings of $46,620 per ED. Telephone and telemedicine consultations were not randomly assigned, potentially resulting in biased results. From a health care payer perspective, telemedicine consultations to health care providers of acutely ill and injured children presenting to rural EDs are cost-saving (base-case and more than half of Monte Carlo simulation iterations) or cost-effective compared with telephone consultations. © The Author(s) 2015.

Cost-utility analysis of screening for diabetic retinopathy in Japan: a probabilistic Markov modeling study.

PubMed

Kawasaki, Ryo; Akune, Yoko; Hiratsuka, Yoshimune; Fukuhara, Shunichi; Yamada, Masakazu

2015-02-01

To evaluate the cost-effectiveness for a screening interval longer than 1 year detecting diabetic retinopathy (DR) through the estimation of incremental costs per quality-adjusted life year (QALY) based on the best available clinical data in Japan. A Markov model with a probabilistic cohort analysis was framed to calculate incremental costs per QALY gained by implementing a screening program detecting DR in Japan. A 1-year cycle length and population size of 50,000 with a 50-year time horizon (age 40-90 years) was used. Best available clinical data from publications and national surveillance data was used, and a model was designed including current diagnosis and management of DR with corresponding visual outcomes. One-way and probabilistic sensitivity analyses were performed considering uncertainties in the parameters. In the base-case analysis, the strategy with a screening program resulted in an incremental cost of 5,147 Japanese yen (¥; US$64.6) and incremental effectiveness of 0.0054 QALYs per person screened. The incremental cost-effectiveness ratio was ¥944,981 (US$11,857) per QALY. The simulation suggested that screening would result in a significant reduction in blindness in people aged 40 years or over (-16%). Sensitivity analyses suggested that in order to achieve both reductions in blindness and cost-effectiveness in Japan, the screening program should screen those aged 53-84 years, at intervals of 3 years or less. An eye screening program in Japan would be cost-effective in detecting DR and preventing blindness from DR, even allowing for the uncertainties in estimates of costs, utility, and current management of DR.

Cost-effectiveness of training rural providers to identify and treat patients at risk for fragility fractures.

PubMed

Nelson, S D; Nelson, R E; Cannon, G W; Lawrence, P; Battistone, M J; Grotzke, M; Rosenblum, Y; LaFleur, J

2014-12-01

This is a cost-effectiveness analysis of training rural providers to identify and treat osteoporosis. Results showed a slight cost savings, increase in life years, increase in treatment rates, and decrease in fracture incidence. However, the results were sensitive to small differences in effectiveness, being cost-effective in 70 % of simulations during probabilistic sensitivity analysis. We evaluated the cost-effectiveness of training rural providers to identify and treat veterans at risk for fragility fractures relative to referring these patients to an urban medical center for specialist care. The model evaluated the impact of training on patient life years, quality-adjusted life years (QALYs), treatment rates, fracture incidence, and costs from the perspective of the Department of Veterans Affairs. We constructed a Markov microsimulation model to compare costs and outcomes of a hypothetical cohort of veterans seen by rural providers. Parameter estimates were derived from previously published studies, and we conducted one-way and probabilistic sensitivity analyses on the parameter inputs. Base-case analysis showed that training resulted in no additional costs and an extra 0.083 life years (0.054 QALYs). Our model projected that as a result of training, more patients with osteoporosis would receive treatment (81.3 vs. 12.2 %), and all patients would have a lower incidence of fractures per 1,000 patient years (hip, 1.628 vs. 1.913; clinical vertebral, 0.566 vs. 1.037) when seen by a trained provider compared to an untrained provider. Results remained consistent in one-way sensitivity analysis and in probabilistic sensitivity analyses, training rural providers was cost-effective (less than $50,000/QALY) in 70 % of the simulations. Training rural providers to identify and treat veterans at risk for fragility fractures has a potential to be cost-effective, but the results are sensitive to small differences in effectiveness. It appears that provider education alone is not enough to make a significant difference in fragility fracture rates among veterans.

Commercialization of NESSUS: Status

NASA Technical Reports Server (NTRS)

Thacker, Ben H.; Millwater, Harry R.

1991-01-01

A plan was initiated in 1988 to commercialize the Numerical Evaluation of Stochastic Structures Under Stress (NESSUS) probabilistic structural analysis software. The goal of the on-going commercialization effort is to begin the transfer of Probabilistic Structural Analysis Method (PSAM) developed technology into industry and to develop additional funding resources in the general area of structural reliability. The commercialization effort is summarized. The SwRI NESSUS Software System is a general purpose probabilistic finite element computer program using state of the art methods for predicting stochastic structural response due to random loads, material properties, part geometry, and boundary conditions. NESSUS can be used to assess structural reliability, to compute probability of failure, to rank the input random variables by importance, and to provide a more cost effective design than traditional methods. The goal is to develop a general probabilistic structural analysis methodology to assist in the certification of critical components in the next generation Space Shuttle Main Engine.

Economic Evaluation of Telemedicine for Patients in ICUs.

PubMed

Yoo, Byung-Kwang; Kim, Minchul; Sasaki, Tomoko; Melnikow, Joy; Marcin, James P

2016-02-01

Despite telemedicine's potential to improve patients' health outcomes and reduce costs in the ICU, hospitals have been slow to introduce telemedicine in the ICU due to high up-front costs and mixed evidence on effectiveness. This study's first aim was to conduct a cost-effectiveness analysis to estimate the incremental cost-effectiveness ratio of telemedicine in the ICU, compared with ICU without telemedicine, from the healthcare system perspective. The second aim was to examine potential cost saving of telemedicine in the ICU through probabilistic analyses and break-even analyses. Simulation analyses performed by standard decision models. Hypothetical ICU defined by the U.S. literature. Hypothetical adult patients in ICU defined by the U.S. literature. The intervention was the introduction of telemedicine in the ICU, which was assumed to affect per-patient per-hospital-stay ICU cost and hospital mortality. Telemedicine in the ICU operation costs included the telemedicine equipment-installation (start-up) costs with 5-year depreciation, maintenance costs, and clinician staffing costs. Telemedicine in the ICU effectiveness was measured by cumulative quality-adjusted life years for 5 years after ICU discharge. The base case cost-effectiveness analysis estimated telemedicine in the ICU to extend 0.011 quality-adjusted life years with an incremental cost of $516 per patient compared with ICU without telemedicine, resulting in an incremental cost-effectiveness ratio of $45,320 per additional quality-adjusted life year (= $516/0.011). The probabilistic cost-effectiveness analysis estimated an incremental cost-effectiveness ratio of $50,265 with a wide 95% CI from a negative value (suggesting cost savings) to $375,870. These probabilistic analyses projected that cost saving is achieved 37% of 1,000 iterations. Cost saving is also feasible if the per-patient per-hospital-stay operational cost and physician cost were less than $422 and less than $155, respectively, based on break-even analyses. Our analyses suggest that telemedicine in the ICU is cost-effective in most cases and cost saving in some cases. The thresholds of cost and effectiveness, estimated by break-even analyses, help hospitals determine the impact of telemedicine in the ICU and potential cost saving.

A cost-effectiveness analysis of two different antimicrobial stewardship programs.

PubMed

Okumura, Lucas Miyake; Riveros, Bruno Salgado; Gomes-da-Silva, Monica Maria; Veroneze, Izelandia

2016-01-01

There is a lack of formal economic analysis to assess the efficiency of antimicrobial stewardship programs. Herein, we conducted a cost-effectiveness study to assess two different strategies of Antimicrobial Stewardship Programs. A 30-day Markov model was developed to analyze how cost-effective was a Bundled Antimicrobial Stewardship implemented in a university hospital in Brazil. Clinical data derived from a historical cohort that compared two different strategies of antimicrobial stewardship programs and had 30-day mortality as main outcome. Selected costs included: workload, cost of defined daily doses, length of stay, laboratory and imaging resources used to diagnose infections. Data were analyzed by deterministic and probabilistic sensitivity analysis to assess model's robustness, tornado diagram and Cost-Effectiveness Acceptability Curve. Bundled Strategy was more expensive (Cost difference US$ 2119.70), however, it was more efficient (US$ 27,549.15 vs 29,011.46). Deterministic and probabilistic sensitivity analysis suggested that critical variables did not alter final Incremental Cost-Effectiveness Ratio. Bundled Strategy had higher probabilities of being cost-effective, which was endorsed by cost-effectiveness acceptability curve. As health systems claim for efficient technologies, this study conclude that Bundled Antimicrobial Stewardship Program was more cost-effective, which means that stewardship strategies with such characteristics would be of special interest in a societal and clinical perspective. Copyright © 2016 Elsevier Editora Ltda. All rights reserved.

A probabilistic analysis of silicon cost

NASA Technical Reports Server (NTRS)

Reiter, L. J.

1983-01-01

Silicon materials costs represent both a cost driver and an area where improvement can be made in the manufacture of photovoltaic modules. The cost from three processes for the production of low-cost silicon being developed under the U.S. Department of Energy's (DOE) National Photovoltaic Program is analyzed. The approach is based on probabilistic inputs and makes use of two models developed at the Jet Propulsion Laboratory: SIMRAND (SIMulation of Research ANd Development) and IPEG (Improved Price Estimating Guidelines). The approach, assumptions, and limitations are detailed along with a verification of the cost analyses methodology. Results, presented in the form of cumulative probability distributions for silicon cost, indicate that there is a 55% chance of reaching the DOE target of $16/kg for silicon material. This is a technically achievable cost based on expert forecasts of the results of ongoing research and development and do not imply any market prices for a given year.

The direct and indirect cost of diabetes in Italy: a prevalence probabilistic approach.

PubMed

Marcellusi, A; Viti, R; Mecozzi, A; Mennini, F S

2016-03-01

Diabetes mellitus is a chronic degenerative disease associated with a high risk of chronic complications and comorbidities. However, very few data are available on the associated cost. The objective of this study is to identify the available information on the epidemiology of the disease and estimate the average annual cost incurred by the National Health Service and Society for the Treatment of Diabetes in Italy. A probabilistic prevalence cost of illness model was developed to calculate an aggregate measure of the economic burden associated with the disease, in terms of direct medical costs (drugs, hospitalizations, monitoring and adverse events) and indirect costs (absenteeism and early retirement). A systematic review of the literature was conducted to determine both the epidemiological and economic data. Furthermore, a one-way and probabilistic sensitivity analysis with 5,000 Monte Carlo simulations was performed to test the robustness of the results and define a 95% CI. The model estimated a prevalence of 2.6 million patients under drug therapies in Italy. The total economic burden of diabetic patients in Italy amounted to €20.3 billion/year (95% CI €18.61 to €22.29 billion), 54% of which are associated with indirect costs (95% CI €10.10 to €11.62 billion) and 46% with direct costs only (95% CI €8.11 to €11.06 billion). This is the first study conducted in Italy aimed at estimating the direct and indirect cost of diabetes with a probabilistic prevalence approach. As might be expected, the lack of information means that the real burden of diabetes is partly underestimated, especially with regard to indirect costs. However, this is a useful approach for policy makers to understand the economic implications of diabetes treatment in Italy.

Palbociclib in hormone receptor positive advanced breast cancer: A cost-utility analysis.

PubMed

Raphael, J; Helou, J; Pritchard, K I; Naimark, D M

2017-11-01

The addition of palbociclib to letrozole improves progression-free survival in the first-line treatment of hormone receptor positive advanced breast cancer (ABC). This study assesses the cost-utility of palbociclib from the Canadian healthcare payer perspective. A probabilistic discrete event simulation (DES) model was developed and parameterised with data from the PALOMA 1 and 2 trials and other sources. The incremental cost per quality-adjusted life-month (QALM) gained for palbociclib was calculated. A time horizon of 15 years was used in the base case with costs and effectiveness discounted at 5% annually. Time-to- progression and time-to-death were derived from a Weibull and exponential distribution. Expected costs were based on Ontario fees and other sources. Probabilistic sensitivity analyses were conducted to account for parameter uncertainty. Compared to letrozole, the addition of palbociclib provided an additional 14.7 QALM at an incremental cost of $161,508. The resulting incremental cost-effectiveness ratio was $10,999/QALM gained. Assuming a willingness-to-pay (WTP) of $4167/QALM, the probability of palbociclib to be cost-effective was 0%. Cost-effectiveness acceptability curves derived from a probabilistic sensitivity analysis showed that at a WTP of $11,000/QALM gained, the probability of palbociclib to be cost-effective was 50%. The addition of palbociclib to letrozole is unlikely to be cost-effective for the treatment of ABC from a Canadian healthcare perspective with its current price. While ABC patients derive a meaningful clinical benefit from palbociclib, considerations should be given to increase the WTP threshold and reduce the drug pricing, to render this strategy more affordable. Copyright © 2017 Elsevier Ltd. All rights reserved.

Integrated Campaign Probabilistic Cost, Schedule, Performance, and Value for Program Office Support

NASA Technical Reports Server (NTRS)

Cornelius, David; Sasamoto, Washito; Daugherty, Kevin; Deacon, Shaun

2012-01-01

This paper describes an integrated assessment tool developed at NASA Langley Research Center that incorporates probabilistic analysis of life cycle cost, schedule, launch performance, on-orbit performance, and value across a series of planned space-based missions, or campaign. Originally designed as an aid in planning the execution of missions to accomplish the National Research Council 2007 Earth Science Decadal Survey, it utilizes Monte Carlo simulation of a series of space missions for assessment of resource requirements and expected return on investment. Interactions between simulated missions are incorporated, such as competition for launch site manifest, to capture unexpected and non-linear system behaviors. A novel value model is utilized to provide an assessment of the probabilistic return on investment. A demonstration case is discussed to illustrate the tool utility.

Cost-utility analysis of great saphenous vein ablation with radiofrequency, foam and surgery in the emerging health-care setting of Thailand.

PubMed

Siribumrungwong, Boonying; Noorit, Pinit; Wilasrusmee, Chumpon; Leelahavarong, Pattara; Thakkinstian, Ammarin; Teerawattananon, Yot

2016-09-01

To conduct economic evaluations of radiofrequency ablation, ultrasound-guided foam sclerotherapy and surgery for great saphenous vein ablation. A cost-utility and cohort analysis from societal perspective was performed to estimate incremental cost-effectiveness ratio. Transitional probabilities were from meta-analysis. Direct medical, direct non-medical, indirect costs, and utility were from standard Thai costings and cohort. Probabilistic sensitivity analysis was performed to assess parameter uncertainties. Seventy-seven patients (31 radiofrequency ablation, 19 ultrasound-guided foam sclerotherapy, and 27 surgeries) were enrolled from October 2011 to February 2013. Compared with surgery, radiofrequency ablation costed 12,935 and 20,872 Baht higher, whereas ultrasound-guided foam sclerotherapy costed 6159 lower and 1558 Bath higher for outpatient and inpatient, respectively. At one year, radiofrequency ablation had slightly lower quality-adjusted life-year, whereas ultrasound-guided foam sclerotherapy yielded additional 0.025 quality-adjusted life-year gained. Because of costing lower and greater quality-adjusted life-year than other compared alternatives, outpatient ultrasound-guided foam sclerotherapy was an option being dominant. Probabilistic sensitivity analysis resulted that at the Thai ceiling threshold of 160,000 Baht/quality-adjusted life-year gained, ultrasound-guided foam sclerotherapy had chances of 0.71 to be cost-effective. Ultrasound-guided foam sclerotherapy seems to be cost-effective for treating great saphenous vein reflux compared to surgery in Thailand at one-year results. © The Author(s) 2015.

Development of coordination system model on single-supplier multi-buyer for multi-item supply chain with probabilistic demand

NASA Astrophysics Data System (ADS)

Olivia, G.; Santoso, A.; Prayogo, D. N.

2017-11-01

Nowadays, the level of competition between supply chains is getting tighter and a good coordination system between supply chains members is very crucial in solving the issue. This paper focused on a model development of coordination system between single supplier and buyers in a supply chain as a solution. Proposed optimization model was designed to determine the optimal number of deliveries from a supplier to buyers in order to minimize the total cost over a planning horizon. Components of the total supply chain cost consist of transportation costs, handling costs of supplier and buyers and also stock out costs. In the proposed optimization model, the supplier can supply various types of items to retailers whose item demand patterns are probabilistic. Sensitivity analysis of the proposed model was conducted to test the effect of changes in transport costs, handling costs and production capacities of the supplier. The results of the sensitivity analysis showed a significant influence on the changes in the transportation cost, handling costs and production capacity to the decisions of the optimal numbers of product delivery for each item to the buyers.

Reliability and risk assessment of structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1991-01-01

Development of reliability and risk assessment of structural components and structures is a major activity at Lewis Research Center. It consists of five program elements: (1) probabilistic loads; (2) probabilistic finite element analysis; (3) probabilistic material behavior; (4) assessment of reliability and risk; and (5) probabilistic structural performance evaluation. Recent progress includes: (1) the evaluation of the various uncertainties in terms of cumulative distribution functions for various structural response variables based on known or assumed uncertainties in primitive structural variables; (2) evaluation of the failure probability; (3) reliability and risk-cost assessment; and (4) an outline of an emerging approach for eventual certification of man-rated structures by computational methods. Collectively, the results demonstrate that the structural durability/reliability of man-rated structural components and structures can be effectively evaluated by using formal probabilistic methods.

Cost-utility analysis of botulinum toxin type A products for the treatment of cervical dystonia.

PubMed

Kazerooni, Rashid; Broadhead, Christine

2015-02-15

A cost-utility analysis of botulinum toxin type A products for the treatment of cervical dystonia (CD) was conducted. A cost-utility analysis of botulinum toxin type A products was conducted from the U.S. government perspective using a decision-analysis model with a one-year time horizon. Probabilities of the model were taken from several studies using the three botulinum type A products approved by the Food and Drug Administration for the treatment of CD: onabotulinumtoxinA (Botox), abobotulinumtoxinA (Dysport), and incobotulinumtoxinA (Xeomin). The main outcome measurement was successful treatment response with botulinum toxin type A, measured in quality-adjusted life years (QALYs). Response was defined as a patient who experienced improvement of CD symptoms without a severe adverse event. Probabilistic sensitivity analysis was conducted to test robustness of the base-case results. All three botulinum toxin type A agents were cost-effective at a willingness-to-pay threshold of $100,000 per QALY. Xeomin was the most cost-effective with a cost-effectiveness ratio of $27,548 per QALY. Xeomin was dominant over the alternative agents with equivalent efficacy outcomes and lower costs. Dysport had the second lowest cost-effectiveness ratio ($36,678), followed by Botox ($49,337). The probabilistic sensitivity analysis supported the results of the base-case analysis. Dysport was associated with the lowest wastage (2.2%), followed by Xeomin (10%) and Botox (22.9%). A cost-utility analysis found that Xeomin was the more cost-effective botulinum toxin type A product compared with Botox and Dysport for the treatment of CD. Wastage associated with the respective products may have a large effect on the cost-effectiveness of the agents. Copyright © 2015 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Space system operations and support cost analysis using Markov chains

NASA Technical Reports Server (NTRS)

Unal, Resit; Dean, Edwin B.; Moore, Arlene A.; Fairbairn, Robert E.

1990-01-01

This paper evaluates the use of Markov chain process in probabilistic life cycle cost analysis and suggests further uses of the process as a design aid tool. A methodology is developed for estimating operations and support cost and expected life for reusable space transportation systems. Application of the methodology is demonstrated for the case of a hypothetical space transportation vehicle. A sensitivity analysis is carried out to explore the effects of uncertainty in key model inputs.

Cost-effectiveness analysis of two treatment strategies for chronic hepatitis C before and after access to direct-acting antivirals in Spain.

PubMed

Turnes, Juan; Domínguez-Hernández, Raquel; Casado, Miguel Ángel

To evaluate the cost-effectiveness of a strategy based on direct-acting antivirals (DAAs) following the marketing of simeprevir and sofosbuvir (post-DAA) versus a pre-direct-acting antiviral strategy (pre-DAA) in patients with chronic hepatitis C, from the perspective of the Spanish National Health System. A decision tree combined with a Markov model was used to estimate the direct health costs (€, 2016) and health outcomes (quality-adjusted life years, QALYs) throughout the patient's life, with an annual discount rate of 3%. The sustained virological response, percentage of patients treated or not treated in each strategy, clinical characteristics of the patients, annual likelihood of transition, costs of treating and managing the disease, and utilities were obtained from the literature. The cost-effectiveness analysis was expressed as an incremental cost-effectiveness ratio (incremental cost per QALY gained). A deterministic sensitivity analysis and a probabilistic sensitivity analysis were performed. The post-DAA strategy showed higher health costs per patient (€30,944 vs. €23,707) than the pre-DAA strategy. However, it was associated with an increase of QALYs gained (15.79 vs. 12.83), showing an incremental cost-effectiveness ratio of €2,439 per QALY. The deterministic sensitivity analysis and the probabilistic sensitivity analysis showed the robustness of the results, with the post-DAA strategy being cost-effective in 99% of cases compared to the pre-DAA strategy. Compared to the pre-DAA strategy, the post-DAA strategy is efficient for the treatment of chronic hepatitis C in Spain, resulting in a much lower cost per QALY than the efficiency threshold used in Spain (€30,000 per QALY). Copyright © 2017 Elsevier España, S.L.U., AEEH y AEG. All rights reserved.

Probabilistic Analysis of Gas Turbine Field Performance

NASA Technical Reports Server (NTRS)

Gorla, Rama S. R.; Pai, Shantaram S.; Rusick, Jeffrey J.

2002-01-01

A gas turbine thermodynamic cycle was computationally simulated and probabilistically evaluated in view of the several uncertainties in the performance parameters, which are indices of gas turbine health. Cumulative distribution functions and sensitivity factors were computed for the overall thermal efficiency and net specific power output due to the thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design, enhance performance, increase system availability and make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in the gas turbine health determination and to the identification of both the most critical measurements and parameters. Probabilistic analysis aims at unifying and improving the control and health monitoring of gas turbine aero-engines by increasing the quality and quantity of information available about the engine's health and performance.

Venoarterial extracorporeal membrane oxygenation for patients in shock or cardiac arrest secondary to cardiotoxicant poisoning: a cost-effectiveness analysis.

PubMed

St-Onge, Maude; Fan, Eddy; Mégarbane, Bruno; Hancock-Howard, Rebecca; Coyte, Peter C

2015-04-01

Venoarterial extracorporeal membrane oxygenation represents an emerging and recommended option to treat life-threatening cardiotoxicant poisoning. The objective of this cost-effectiveness analysis was to estimate the incremental cost-effectiveness ratio of using venoarterial extracorporeal membrane oxygenation for adults in cardiotoxicant-induced shock or cardiac arrest compared with standard care. Adults in shock or in cardiac arrest secondary to cardiotoxicant poisoning were studied with a lifetime horizon and a societal perspective. Venoarterial extracorporeal membrane oxygenation cost effectiveness was calculated using a decision analysis tree, with the effect of the intervention and the probabilities used in the model taken from an observational study representing the highest level of evidence available. The costs (2013 Canadian dollars, where $1.00 Canadian = $0.9562 US dollars) were documented with interviews, reviews of official provincial documents, or published articles. A series of one-way sensitivity analyses and a probabilistic sensitivity analysis using Monte Carlo simulation were used to evaluate uncertainty in the decision model. The cost per life year (LY) gained in the extracorporeal membrane oxygenation group was $145 931/18 LY compared with $88 450/10 LY in the non-extracorporeal membrane oxygenation group. The incremental cost-effectiveness ratio ($7185/LY but $34 311/LY using a more pessimistic approach) was mainly influenced by the probability of survival. The probabilistic sensitivity analysis identified variability in both cost and effectiveness. Venoarterial extracorporeal membrane oxygenation may be cost effective in treating cardiotoxicant poisonings. Copyright © 2014 Elsevier Inc. All rights reserved.

Cost-Effectiveness of Endovascular Stroke Therapy: A Patient Subgroup Analysis From a US Healthcare Perspective.

PubMed

Kunz, Wolfgang G; Hunink, M G Myriam; Sommer, Wieland H; Beyer, Sebastian E; Meinel, Felix G; Dorn, Franziska; Wirth, Stefan; Reiser, Maximilian F; Ertl-Wagner, Birgit; Thierfelder, Kolja M

2016-11-01

Endovascular therapy in addition to standard care (EVT+SC) has been demonstrated to be more effective than SC in acute ischemic large vessel occlusion stroke. Our aim was to determine the cost-effectiveness of EVT+SC depending on patients' initial National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset, Alberta Stroke Program Early CT Score (ASPECTS), and occlusion location. A decision model based on Markov simulations estimated lifetime costs and quality-adjusted life years (QALYs) associated with both strategies applied in a US setting. Model input parameters were obtained from the literature, including recently pooled outcome data of 5 randomized controlled trials (ESCAPE [Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke], EXTEND-IA [Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial], MR CLEAN [Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands], REVASCAT [Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within 8 Hours of Symptom Onset], and SWIFT PRIME [Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment]). Probabilistic sensitivity analysis was performed to estimate uncertainty of the model results. Net monetary benefits, incremental costs, incremental effectiveness, and incremental cost-effectiveness ratios were derived from the probabilistic sensitivity analysis. The willingness-to-pay was set to $50 000/QALY. Overall, EVT+SC was cost-effective compared with SC (incremental cost: $4938, incremental effectiveness: 1.59 QALYs, and incremental cost-effectiveness ratio: $3110/QALY) in 100% of simulations. In all patient subgroups, EVT+SC led to gained QALYs (range: 0.47-2.12), and mean incremental cost-effectiveness ratios were considered cost-effective. However, subgroups with ASPECTS ≤5 or with M2 occlusions showed considerably higher incremental cost-effectiveness ratios ($14 273/QALY and $28 812/QALY, respectively) and only reached suboptimal acceptability in the probabilistic sensitivity analysis (75.5% and 59.4%, respectively). All other subgroups had acceptability rates of 90% to 100%. EVT+SC is cost-effective in most subgroups. In patients with ASPECTS ≤5 or with M2 occlusions, cost-effectiveness remains uncertain based on current data. © 2016 American Heart Association, Inc.

Probabilistic/Fracture-Mechanics Model For Service Life

NASA Technical Reports Server (NTRS)

Watkins, T., Jr.; Annis, C. G., Jr.

1991-01-01

Computer program makes probabilistic estimates of lifetime of engine and components thereof. Developed to fill need for more accurate life-assessment technique that avoids errors in estimated lives and provides for statistical assessment of levels of risk created by engineering decisions in designing system. Implements mathematical model combining techniques of statistics, fatigue, fracture mechanics, nondestructive analysis, life-cycle cost analysis, and management of engine parts. Used to investigate effects of such engine-component life-controlling parameters as return-to-service intervals, stresses, capabilities for nondestructive evaluation, and qualities of materials.

Cost-effectiveness of a quality improvement programme to reduce central line-associated bloodstream infections in intensive care units in the USA

PubMed Central

Herzer, Kurt R; Niessen, Louis; Constenla, Dagna O; Ward, William J; Pronovost, Peter J

2014-01-01

Objective To assess the cost-effectiveness of a multifaceted quality improvement programme focused on reducing central line-associated bloodstream infections in intensive care units. Design Cost-effectiveness analysis using a decision tree model to compare programme to non-programme intensive care units. Setting USA. Population Adult patients in the intensive care unit. Costs Economic costs of the programme and of central line-associated bloodstream infections were estimated from the perspective of the hospital and presented in 2013 US dollars. Main outcome measures Central line-associated bloodstream infections prevented, deaths averted due to central line-associated bloodstream infections prevented, and incremental cost-effectiveness ratios. Probabilistic sensitivity analysis was performed. Results Compared with current practice, the programme is strongly dominant and reduces bloodstream infections and deaths at no additional cost. The probabilistic sensitivity analysis showed that there was an almost 80% probability that the programme reduces bloodstream infections and the infections’ economic costs to hospitals. The opportunity cost of a bloodstream infection to a hospital was the most important model parameter in these analyses. Conclusions This multifaceted quality improvement programme, as it is currently implemented by hospitals on an increasingly large scale in the USA, likely reduces the economic costs of central line-associated bloodstream infections for US hospitals. Awareness among hospitals about the programme's benefits should enhance implementation. The programme's implementation has the potential to substantially reduce morbidity, mortality and economic costs associated with central line-associated bloodstream infections. PMID:25256190

Cost-effectiveness analysis reveals microsurgical varicocele repair is superior to percutaneous embolization in the treatment of male infertility.

PubMed

Kovac, Jason Ronald; Fantus, Jake; Lipshultz, Larry I; Fischer, Marc Anthony; Klinghoffer, Zachery

2014-09-01

Varicoceles are a common cause of male infertility; repair can be accomplished using either surgical or radiological means. We compare the cost-effectiveness of the gold standard, the microsurgical varicocele repair (MV), to the options of a nonmicrosurgical approach (NMV) and percutaneous embolization (PE) to manage varicocele-associated infertility. A Markov decision-analysis model was developed to estimate costs and pregnancy rates. Within the model, recurrences following MV and NMV were re-treated with PE and recurrences following PE were treated with repeat PE, MV or NMV. Pregnancy and recurrence rates were based on the literature, while costs were obtained from institutional and government supplied data. Univariate and probabilistic sensitivity-analyses were performed to determine the effects of the various parameters on model outcomes. Primary treatment with MV was the most cost-effective strategy at $5402 CAD (Canadian)/pregnancy. Primary treatment with NMV was the least costly approach, but it also yielded the fewest pregnancies. Primary treatment with PE was the least cost-effective strategy costing about $7300 CAD/pregnancy. Probabilistic sensitivity analysis reinforced MV as the most cost-effective strategy at a willingness-to-pay threshold of >$4100 CAD/pregnancy. MV yielded the most pregnancies at acceptable levels of incremental costs. As such, it is the preferred primary treatment strategy for varicocele-associated infertility. Treatment with PE was the least cost-effective approach and, as such, is best used only in cases of surgical failure.

The cost-effectiveness of nonoperative management versus laparoscopic appendectomy for the treatment of acute, uncomplicated appendicitis in children.

PubMed

Wu, James X; Sacks, Greg D; Dawes, Aaron J; DeUgarte, Daniel; Lee, Steven L

2017-07-01

Several studies have demonstrated the safety and short-term success of nonoperative management in children with acute, uncomplicated appendicitis. Nonoperative management spares the patients and their family the upfront cost and discomfort of surgery, but also risks recurrent appendicitis. Using decision-tree software, we evaluated the cost-effectiveness of nonoperative management versus routine laparoscopic appendectomy. Model variables were abstracted from a review of the literature, Healthcare Cost and Utilization Project, and Medicare Physician Fee schedule. Model uncertainty was assessed using both one-way and probabilistic sensitivity analyses. We used a $100,000 per quality adjusted life year (QALY) threshold for cost-effectiveness. Operative management cost $11,119 and yielded 23.56 quality-adjusted life months (QALMs). Nonoperative management cost $2277 less than operative management, but yielded 0.03 fewer QALMs. The incremental cost-to-effectiveness ratio of routine laparoscopic appendectomy was $910,800 per QALY gained. This greatly exceeds the $100,000/QALY threshold and was not cost-effective. One-way sensitivity analysis found that operative management would become cost-effective if the 1-year recurrence rate of acute appendicitis exceeded 39.8%. Probabilistic sensitivity analysis indicated that nonoperative management was cost-effective in 92% of simulations. Based on our model, nonoperative management is more cost-effective than routine laparoscopic appendectomy for children with acute, uncomplicated appendicitis. Cost-Effectiveness Study: Level II. Published by Elsevier Inc.

Cost-effectiveness analysis of influenza and pneumococcal vaccination for Hong Kong elderly in long-term care facilities.

PubMed

You, J H S; Wong, W C W; Ip, M; Lee, N L S; Ho, S C

2009-11-01

To compare cost and quality-adjusted life-years (QALYs) gained by influenza vaccination with or without pneumococcal vaccination in the elderly living in long-term care facilities (LTCFs). Cost-effectiveness analysis based on Markov modelling over 5 years, from a Hong Kong public health provider's perspective, on a hypothetical cohort of LTCF residents aged > or = 65 years. Benefit-cost ratio (BCR) and net present value (NPV) of two vaccination strategies versus no vaccination were estimated. The cost and QALYs gained by two vaccination strategies were compared by Student's t-test in probabilistic sensitivity analysis (10,000 Monte Carlo simulations). Both vaccination strategies had high BCRs and NPVs (6.39 and US$334 for influenza vaccination; 5.10 and US$332 for influenza plus pneumococcal vaccination). In base case analysis, the two vaccination strategies were expected to cost less and gain higher QALYs than no vaccination. In probabilistic sensitivity analysis, the cost of combined vaccination and influenza vaccination was significantly lower (p<0.001) than the cost of no vaccination. Both vaccination strategies gained significantly higher (p<0.001) QALYs than no vaccination. The QALYs gained by combined vaccination were significantly higher (p = 0.030) than those gained by influenza vaccination alone. The total cost of combined vaccination was significantly lower (p = 0.011) than that of influenza vaccination. Influenza vaccination with or without pneumococcal vaccination appears to be less costly with higher QALYs gained than no vaccination, over a 5-year period, for elderly people living in LTCFs from the perspective of a Hong Kong public health organisation. Combined vaccination was more likely to gain higher QALYs with lower total cost than influenza vaccination alone.

Cost-effectiveness of drug-eluting stents versus bare-metal stents in patients undergoing percutaneous coronary intervention.

PubMed

Baschet, Louise; Bourguignon, Sandrine; Marque, Sébastien; Durand-Zaleski, Isabelle; Teiger, Emmanuel; Wilquin, Fanny; Levesque, Karine

2016-01-01

To determine the cost-effectiveness of drug-eluting stents (DES) compared with bare-metal stents (BMS) in patients requiring a percutaneous coronary intervention in France, using a recent meta-analysis including second-generation DES. A cost-effectiveness analysis was performed in the French National Health Insurance setting. Effectiveness settings were taken from a meta-analysis of 117 762 patient-years with 76 randomised trials. The main effectiveness criterion was major cardiac event-free survival. Effectiveness and costs were modelled over a 5-year horizon using a three-state Markov model. Incremental cost-effectiveness ratios and a cost-effectiveness acceptability curve were calculated for a range of thresholds for willingness to pay per year without major cardiac event gain. Deterministic and probabilistic sensitivity analyses were performed. Base case results demonstrated that DES are dominant over BMS, with an increase in event-free survival and a cost-reduction of €184, primarily due to a diminution of second revascularisations, and an absence of myocardial infarction and stent thrombosis. These results are robust for uncertainty on one-way deterministic and probabilistic sensitivity analyses. Using a cost-effectiveness threshold of €7000 per major cardiac event-free year gained, DES has a >95% probability of being cost-effective versus BMS. Following DES price decrease, new-generation DES development and taking into account recent meta-analyses results, the DES can now be considered cost-effective regardless of selective indication in France, according to European recommendations.

Economic Evaluation of a Patient-Directed Music Intervention for ICU Patients Receiving Mechanical Ventilatory Support.

PubMed

Chlan, Linda L; Heiderscheit, Annette; Skaar, Debra J; Neidecker, Marjorie V

2018-05-04

Music intervention has been shown to reduce anxiety and sedative exposure among mechanically ventilated patients. Whether music intervention reduces ICU costs is not known. The aim of this study was to examine ICU costs for patients receiving a patient-directed music intervention compared with patients who received usual ICU care. A cost-effectiveness analysis from the hospital perspective was conducted to determine if patient-directed music intervention was cost-effective in improving patient-reported anxiety. Cost savings were also evaluated. One-way and probabilistic sensitivity analyses determined the influence of input variation on the cost-effectiveness. Midwestern ICUs. Adult ICU patients from a parent clinical trial receiving mechanical ventilatory support. Patients receiving the experimental patient-directed music intervention received a MP3 player, noise-canceling headphones, and music tailored to individual preferences by a music therapist. The base case cost-effectiveness analysis estimated patient-directed music intervention reduced anxiety by 19 points on the Visual Analogue Scale-Anxiety with a reduction in cost of $2,322/patient compared with usual ICU care, resulting in patient-directed music dominance. The probabilistic cost-effectiveness analysis found that average patient-directed music intervention costs were $2,155 less than usual ICU care and projected that cost saving is achieved in 70% of 1,000 iterations. Based on break-even analyses, cost saving is achieved if the per-patient cost of patient-directed music intervention remains below $2,651, a value eight times the base case of $329. Patient-directed music intervention is cost-effective for reducing anxiety in mechanically ventilated ICU patients.

Reliability-Based Stability Analysis of Rock Slopes Using Numerical Analysis and Response Surface Method

NASA Astrophysics Data System (ADS)

Dadashzadeh, N.; Duzgun, H. S. B.; Yesiloglu-Gultekin, N.

2017-08-01

While advanced numerical techniques in slope stability analysis are successfully used in deterministic studies, they have so far found limited use in probabilistic analyses due to their high computation cost. The first-order reliability method (FORM) is one of the most efficient probabilistic techniques to perform probabilistic stability analysis by considering the associated uncertainties in the analysis parameters. However, it is not possible to directly use FORM in numerical slope stability evaluations as it requires definition of a limit state performance function. In this study, an integrated methodology for probabilistic numerical modeling of rock slope stability is proposed. The methodology is based on response surface method, where FORM is used to develop an explicit performance function from the results of numerical simulations. The implementation of the proposed methodology is performed by considering a large potential rock wedge in Sumela Monastery, Turkey. The accuracy of the developed performance function to truly represent the limit state surface is evaluated by monitoring the slope behavior. The calculated probability of failure is compared with Monte Carlo simulation (MCS) method. The proposed methodology is found to be 72% more efficient than MCS, while the accuracy is decreased with an error of 24%.

Applying a private sector capitation model to the management of type 2 diabetes in the South African public sector: a cost-effectiveness analysis.

PubMed

Volmink, Heinrich C; Bertram, Melanie Y; Jina, Ruxana; Wade, Alisha N; Hofman, Karen J

2014-09-30

Diabetes mellitus contributes substantially to the non-communicable disease burden in South Africa. The proposed National Health Insurance system provides an opportunity to consider the development of a cost-effective capitation model of care for patients with type 2 diabetes. The objective of the study was to determine the potential cost-effectiveness of adapting a private sector diabetes management programme (DMP) to the South African public sector. Cost-effectiveness analysis was undertaken with a public sector model of the DMP as the intervention and a usual practice model as the comparator. Probabilistic modelling was utilized for incremental cost-effectiveness ratio analysis with life years gained selected as the outcome. Secondary data were used to design the model while cost information was obtained from various sources, taking into account public sector billing. Modelling found an incremental cost-effectiveness ratio (ICER) of ZAR 8 356 (USD 1018) per life year gained (LYG) for the DMP against the usual practice model. This fell substantially below the Willingness-to-Pay threshold with bootstrapping analysis. Furthermore, a national implementation of the intervention could potentially result in an estimated cumulative gain of 96 997 years of life (95% CI 71 073 years - 113 994 years). Probabilistic modelling found the capitation intervention to be cost-effective, with an ICER of ZAR 8 356 (USD 1018) per LYG. Piloting the service within the public sector is recommended as an initial step, as this would provide data for more accurate economic evaluation, and would also allow for qualitative analysis of the programme.

Budget impact analysis of trastuzumab in early breast cancer: a hospital district perspective.

PubMed

Purmonen, Timo T; Auvinen, Päivi K; Martikainen, Janne A

2010-04-01

Adjuvant trastuzumab is widely used in HER2-positive (HER2+) early breast cancer, and despite its cost-effectiveness, it causes substantial costs for health care. The purpose of the study was to develop a tool for estimating the budget impact of new cancer treatments. With this tool, we were able to estimate the budget impact of adjuvant trastuzumab, as well as the probability of staying within a given budget constraint. The created model-based evaluation tool was used to explore the budget impact of trastuzumab in early breast cancer in a single Finnish hospital district with 250,000 inhabitants. The used model took into account the number of patients, HER2+ prevalence, length and cost of treatment, and the effectiveness of the therapy. Probabilistic sensitivity analysis and alternative case scenarios were performed to ensure the robustness of the results. Introduction of adjuvant trastuzumab caused substantial costs for a relatively small hospital district. In base-case analysis the 4-year net budget impact was 1.3 million euro. The trastuzumab acquisition costs were partially offset by the reduction in costs associated with the treatment of cancer recurrence and metastatic disease. Budget impact analyses provide important information about the overall economic impact of new treatments, and thus offer complementary information to cost-effectiveness analyses. Inclusion of treatment outcomes and probabilistic sensitivity analysis provides more realistic estimates of the net budget impact. The length of trastuzumab treatment has a strong effect on the budget impact.

Evaluation of a Stratified National Breast Screening Program in the United Kingdom: An Early Model-Based Cost-Effectiveness Analysis.

PubMed

Gray, Ewan; Donten, Anna; Karssemeijer, Nico; van Gils, Carla; Evans, D Gareth; Astley, Sue; Payne, Katherine

2017-09-01

To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1, risk 2, masking [supplemental screening for women with higher breast density], and masking and risk 1) compared with the current UK NBSP and no screening. The model assumed a lifetime horizon, the health service perspective to identify costs (£, 2015), and measured consequences in quality-adjusted life-years (QALYs). Multiple data sources were used: systematic reviews of effectiveness and utility, published studies reporting costs, and cohort studies embedded in existing NBSPs. Model parameter uncertainty was assessed using probabilistic sensitivity analysis and one-way sensitivity analysis. The base-case analysis, supported by probabilistic sensitivity analysis, suggested that the risk stratified NBSPs (risk 1 and risk-2) were relatively cost-effective when compared with the current UK NBSP, with incremental cost-effectiveness ratios of £16,689 per QALY and £23,924 per QALY, respectively. Stratified NBSP including masking approaches (supplemental screening for women with higher breast density) was not a cost-effective alternative, with incremental cost-effectiveness ratios of £212,947 per QALY (masking) and £75,254 per QALY (risk 1 and masking). When compared with no screening, all stratified NBSPs could be considered cost-effective. Key drivers of cost-effectiveness were discount rate, natural history model parameters, mammographic sensitivity, and biopsy rates for recalled cases. A key assumption was that the risk model used in the stratification process was perfectly calibrated to the population. This early model-based cost-effectiveness analysis provides indicative evidence for decision makers to understand the key drivers of costs and QALYs for exemplar stratified NBSP. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

[Cost-minimization analysis of subcutaneous abatacept in the treatment of rheumatoid arthritis in Spain].

PubMed

Ariza, R; Van Walsem, A; Canal, C; Roldán, C; Betegón, L; Oyagüez, I; Janssen, K

2014-07-01

To compare the cost of treating rheumatoid arthritis patients that have failed an initial treatment with methotrexate, with subcutaneous abatacept versus other first-line biologic disease-modifying antirheumatic drugs. Subcutaneous abatacept was considered comparable to intravenous abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, infliximab and tocilizumab, based on indirect comparison using mixed treatment analysis. A cost-minimization analysis was therefore considered appropriate. The Spanish Health System perspective and a 3 year time horizon were selected. Pharmaceutical and administration costs (Euros 2013) of all available first-line biological disease-modifying antirheumatic drugs were considered. Administration costs were obtained from a local costs database. Patients were considered to have a weight of 70 kg. A 3% annual discount rate was applied. Deterministic and probabilistic sensitivity analyses were performed. Subcutaneous abatacept proved in the base case to be less costly than all other biologic antirrheumatic drugs (ranging from Euros -831.42 to Euros -9,741.69 versus infliximab and tocilizumab, respectively). Subcutaneous abatacept was associated with a cost of Euros 10,760.41 per patient during the first year of treatment and Euros 10,261.29 in subsequent years. The total 3-year cost of subcutaneous abatacept was Euros 29,953.89 per patient. Sensitivity analyses proved the model to be robust. Subcutaneous abatacept remained cost-saving in 100% of probabilistic sensitivity analysis simulations versus adalimumab, certolizumab, etanercept and golimumab, in more than 99.6% versus intravenous abatacept and tocilizumab and in 62.3% versus infliximab. Treatment with subcutaneous abatacept is cost-saving versus intravenous abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab and tocilizumab in the management of rheumatoid arthritis patients initiating treatment with biological antirheumatic drugs. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Improving the quality of pressure ulcer care with prevention: a cost-effectiveness analysis.

PubMed

Padula, William V; Mishra, Manish K; Makic, Mary Beth F; Sullivan, Patrick W

2011-04-01

In October 2008, Centers for Medicare and Medicaid Services discontinued reimbursement for hospital-acquired pressure ulcers (HAPUs), thus placing stress on hospitals to prevent incidence of this costly condition. To evaluate whether prevention methods are cost-effective compared with standard care in the management of HAPUs. A semi-Markov model simulated the admission of patients to an acute care hospital from the time of admission through 1 year using the societal perspective. The model simulated health states that could potentially lead to an HAPU through either the practice of "prevention" or "standard care." Univariate sensitivity analyses, threshold analyses, and Bayesian multivariate probabilistic sensitivity analysis using 10,000 Monte Carlo simulations were conducted. Cost per quality-adjusted life-years (QALYs) gained for the prevention of HAPUs. Prevention was cost saving and resulted in greater expected effectiveness compared with the standard care approach per hospitalization. The expected cost of prevention was $7276.35, and the expected effectiveness was 11.241 QALYs. The expected cost for standard care was $10,053.95, and the expected effectiveness was 9.342 QALYs. The multivariate probabilistic sensitivity analysis showed that prevention resulted in cost savings in 99.99% of the simulations. The threshold cost of prevention was $821.53 per day per person, whereas the cost of prevention was estimated to be $54.66 per day per person. This study suggests that it is more cost effective to pay for prevention of HAPUs compared with standard care. Continuous preventive care of HAPUs in acutely ill patients could potentially reduce incidence and prevalence, as well as lead to lower expenditures.

Cost-effectiveness of a quality improvement programme to reduce central line-associated bloodstream infections in intensive care units in the USA.

PubMed

Herzer, Kurt R; Niessen, Louis; Constenla, Dagna O; Ward, William J; Pronovost, Peter J

2014-09-25

To assess the cost-effectiveness of a multifaceted quality improvement programme focused on reducing central line-associated bloodstream infections in intensive care units. Cost-effectiveness analysis using a decision tree model to compare programme to non-programme intensive care units. USA. Adult patients in the intensive care unit. Economic costs of the programme and of central line-associated bloodstream infections were estimated from the perspective of the hospital and presented in 2013 US dollars. Central line-associated bloodstream infections prevented, deaths averted due to central line-associated bloodstream infections prevented, and incremental cost-effectiveness ratios. Probabilistic sensitivity analysis was performed. Compared with current practice, the programme is strongly dominant and reduces bloodstream infections and deaths at no additional cost. The probabilistic sensitivity analysis showed that there was an almost 80% probability that the programme reduces bloodstream infections and the infections' economic costs to hospitals. The opportunity cost of a bloodstream infection to a hospital was the most important model parameter in these analyses. This multifaceted quality improvement programme, as it is currently implemented by hospitals on an increasingly large scale in the USA, likely reduces the economic costs of central line-associated bloodstream infections for US hospitals. Awareness among hospitals about the programme's benefits should enhance implementation. The programme's implementation has the potential to substantially reduce morbidity, mortality and economic costs associated with central line-associated bloodstream infections. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Orthopaedic trauma care in Haiti: a cost-effectiveness analysis of an innovative surgical residency program.

PubMed

Carlson, Lucas C; Slobogean, Gerard P; Pollak, Andrew N

2012-01-01

In an effort to sustainably strengthen orthopaedic trauma care in Haiti, a 2-year Orthopaedic Trauma Care Specialist (OTCS) program for Haitian physicians has been developed. The program will provide focused training in orthopaedic trauma surgery and fracture care utilizing a train-the-trainer approach. The purpose of this analysis was to calculate the cost-effectiveness of the program relative to its potential to decrease disability in the Haitian population. Using established methodology originally outlined in the World Health Organization's Global Burden of Disease project, a cost-effectiveness analysis was performed for the OTCS program in Haiti. Costs and disability-adjusted life-years (DALYs) averted were estimated per fellow trained in the OTCS program by using a 20-year career time horizon. Probabilistic sensitivity analysis was used to simultaneously test the joint uncertainty of the cost and averted DALY estimates. A willingness-to-pay threshold of $1200 per DALY averted, equal to the gross domestic product per capita in Haiti, was selected on the basis of World Health Organization's definition of highly cost-effective health interventions. The OTCS program results in an incremental cost of $1,542,544 ± $109,134 and 12,213 ± 2,983 DALYs averted per fellow trained. The cost-effectiveness ratio of $133.97 ± $34.71 per DALY averted is well below the threshold of $1200 per DALY averted. Furthermore, sensitivity analysis suggests that implementing the OTCS program is the economically preferred strategy with more than 95% probability at a willingness-to-pay threshold of $200 per DALY averted and across the entire range of potential variable inputs. The current economic analysis suggests the OTCS program to be a highly cost-effective intervention. Probabilistic sensitivity analysis demonstrates that the conclusions remain stable even when considering the joint uncertainty of the cost and DALY estimates. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Costs of trastuzumab in combination with chemotherapy for HER2-positive advanced gastric or gastroesophageal junction cancer: an economic evaluation in the Chinese context.

PubMed

Wu, Bin; Ye, Ming; Chen, Huafeng; Shen, Jinfang F

2012-02-01

Adding trastuzumab to a conventional regimen of chemotherapy can improve survival in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastroesophageal junction (GEJ) cancer, but the economic impact of this practice is unknown. The purpose of this cost-effectiveness analysis was to estimate the effects of adding trastuzumab to standard chemotherapy in patients with HER2-positive advanced gastric or GEJ cancer on health and economic outcomes in China. A Markov model was developed to simulate the clinical course of typical patients with HER2-positive advanced gastric or GEJ cancer. Five-year quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs) were estimated. Model inputs were derived from the published literature and government sources. Direct costs were estimated from the perspective of Chinese society. One-way and probabilistic sensitivity analyses were conducted. On baseline analysis, the addition of trastuzumab increased cost and QALY by $56,004.30 (year-2010 US $) and 0.18, respectively, relative to conventional chemotherapy, resulting in an ICER of $251,667.10/QALY gained. Probabilistic sensitivity analyses supported that the addition of trastuzumab was not cost-effective. Budgetary impact analysis estimated that the annual increase in fiscal expenditures would be ~$1 billion. On univariate sensitivity analysis, the median overall survival time for conventional chemotherapy was the most influential factor with respect to the robustness of the model. The findings from the present analysis suggest that the addition of trastuzumab to conventional chemotherapy might not be cost-effective in patients with HER2-positive advanced gastric or GEJ cancer. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

Weighing costs and losses: A decision making game using probabilistic forecasts

NASA Astrophysics Data System (ADS)

Werner, Micha; Ramos, Maria-Helena; Wetterhall, Frederik; Cranston, Michael; van Andel, Schalk-Jan; Pappenberger, Florian; Verkade, Jan

2017-04-01

Probabilistic forecasts are increasingly recognised as an effective and reliable tool to communicate uncertainties. The economic value of probabilistic forecasts has been demonstrated by several authors, showing the benefit to using probabilistic forecasts over deterministic forecasts in several sectors, including flood and drought warning, hydropower, and agriculture. Probabilistic forecasting is also central to the emerging concept of risk-based decision making, and underlies emerging paradigms such as impact-based forecasting. Although the economic value of probabilistic forecasts is easily demonstrated in academic works, its evaluation in practice is more complex. The practical use of probabilistic forecasts requires decision makers to weigh the cost of an appropriate response to a probabilistic warning against the projected loss that would occur if the event forecast becomes reality. In this paper, we present the results of a simple game that aims to explore how decision makers are influenced by the costs required for taking a response and the potential losses they face in case the forecast flood event occurs. Participants play the role of one of three possible different shop owners. Each type of shop has losses of quite different magnitude, should a flood event occur. The shop owners are presented with several forecasts, each with a probability of a flood event occurring, which would inundate their shop and lead to those losses. In response, they have to decide if they want to do nothing, raise temporary defences, or relocate their inventory. Each action comes at a cost; and the different shop owners therefore have quite different cost/loss ratios. The game was played on four occasions. Players were attendees of the ensemble hydro-meteorological forecasting session of the 2016 EGU Assembly, professionals participating at two other conferences related to hydrometeorology, and a group of students. All audiences were familiar with the principles of forecasting and water-related risks, and one of the audiences comprised a group of experts in probabilistic forecasting. Results show that the different shop owners do take the costs of taking action and the potential losses into account in their decisions. Shop owners with a low cost/loss ratio were found to be more inclined to take actions based on the forecasts, though the absolute value of the losses also increased the willingness to take action. Little differentiation was found between the different groups of players.

Value for money? Array genomic hybridization for diagnostic testing for genetic causes of intellectual disability.

PubMed

Regier, Dean A; Friedman, Jan M; Marra, Carlo A

2010-05-14

Array genomic hybridization (AGH) provides a higher detection rate than does conventional cytogenetic testing when searching for chromosomal imbalance causing intellectual disability (ID). AGH is more costly than conventional cytogenetic testing, and it remains unclear whether AGH provides good value for money. Decision analytic modeling was used to evaluate the trade-off between costs, clinical effectiveness, and benefit of an AGH testing strategy compared to a conventional testing strategy. The trade-off between cost and effectiveness was expressed via the incremental cost-effectiveness ratio. Probabilistic sensitivity analysis was performed via Monte Carlo simulation. The baseline AGH testing strategy led to an average cost increase of $217 (95% CI $172-$261) per patient and an additional 8.2 diagnoses in every 100 tested (0.082; 95% CI 0.044-0.119). The mean incremental cost per additional diagnosis was $2646 (95% CI $1619-$5296). Probabilistic sensitivity analysis demonstrated that there was a 95% probability that AGH would be cost effective if decision makers were willing to pay $4550 for an additional diagnosis. Our model suggests that using AGH instead of conventional karyotyping for most ID patients provides good value for money. Deterministic sensitivity analysis found that employing AGH after first-line cytogenetic testing had proven uninformative did not provide good value for money when compared to using AGH as first-line testing. Copyright (c) 2010 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Anal Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodges, Joseph C., E-mail: joseph.hodges@utsouthwestern.edu; Beg, Muhammad S.; Das, Prajnan

2014-07-15

Purpose: To compare the cost-effectiveness of intensity modulated radiation therapy (IMRT) and 3-dimensional conformal radiation therapy (3D-CRT) for anal cancer and determine disease, patient, and treatment parameters that influence the result. Methods and Materials: A Markov decision model was designed with the various disease states for the base case of a 65-year-old patient with anal cancer treated with either IMRT or 3D-CRT and concurrent chemotherapy. Health states accounting for rates of local failure, colostomy failure, treatment breaks, patient prognosis, acute and late toxicities, and the utility of toxicities were informed by existing literature and analyzed with deterministic and probabilistic sensitivitymore » analysis. Results: In the base case, mean costs and quality-adjusted life expectancy in years (QALY) for IMRT and 3D-CRT were $32,291 (4.81) and $28,444 (4.78), respectively, resulting in an incremental cost-effectiveness ratio of $128,233/QALY for IMRT compared with 3D-CRT. Probabilistic sensitivity analysis found that IMRT was cost-effective in 22%, 47%, and 65% of iterations at willingness-to-pay thresholds of $50,000, $100,000, and $150,000 per QALY, respectively. Conclusions: In our base model, IMRT was a cost-ineffective strategy despite the reduced acute treatment toxicities and their associated costs of management. The model outcome was sensitive to variations in local and colostomy failure rates, as well as patient-reported utilities relating to acute toxicities.« less

Time-Series Modeling and Simulation for Comparative Cost-Effective Analysis in Cancer Chemotherapy: An Application to Platinum-Based Regimens for Advanced Non-small Cell Lung Cancer.

PubMed

Chisaki, Yugo; Nakamura, Nobuhiko; Yano, Yoshitaka

2017-01-01

The purpose of this study was to propose a time-series modeling and simulation (M&S) strategy for probabilistic cost-effective analysis in cancer chemotherapy using a Monte-Carlo method based on data available from the literature. The simulation included the cost for chemotherapy, for pharmaceutical care for adverse events (AEs) and other medical costs. As an application example, we describe the analysis for the comparison of four regimens, cisplatin plus irinotecan, carboplatin plus paclitaxel, cisplatin plus gemcitabine (GP), and cisplatin plus vinorelbine, for advanced non-small cell lung cancer. The factors, drug efficacy explained by overall survival or time to treatment failure, frequency and severity of AEs, utility value of AEs to determine QOL, the drugs' and other medical costs in Japan, were included in the model. The simulation was performed and quality adjusted life years (QALY) and incremental cost-effectiveness ratios (ICER) were calculated. An index, percentage of superiority (%SUP) which is the rate of the increased cost vs. QALY-gained plots within the area of positive QALY-gained and also below some threshold values of the ICER, was calculated as functions of threshold values of the ICER. An M&S process was developed, and for the simulation example, the GP regimen was the most cost-effective, in case of threshold values of the ICER=$70000/year, the %SUP for the GP are more than 50%. We developed an M&S process for probabilistic cost-effective analysis, this method would be useful for decision-making in choosing a cancer chemotherapy regimen in terms of pharmacoeconomic.

Cost-effectiveness simulation analysis of schizophrenia at the Instituto Mexicano del Seguro Social: Assessment of typical and atypical antipsychotics.

PubMed

Mould-Quevedo, Joaquín; Contreras-Hernández, Iris; Verduzco, Wáscar; Mejía-Aranguré, Juan Manuel; Garduño-Espinosa, Juan

2009-07-01

Estimation of the economic costs of schizophrenia is a fundamental tool for a better understanding of the magnitude of this health problem. The aim of this study was to estimate the costs and effectiveness of five antipsychotic treatments (ziprasidone, olanzapine, risperidone, haloperidol and clozapine), which are included in the national formulary at the Instituto Mexicano del Seguro Social, through a simulation model. Type of economic evaluation: complete economic evaluation of cost-effectiveness. direct medical costs. 1 year. Effectiveness measure: number of months free of psychotic symptoms. to estimate cost-effectiveness, a Markov model was constructed and a Monte Carlo simulation was carried out. Effectiveness: the results of the Markov model showed that the antipsychotic with the highest number months free of psychotic symptoms was ziprasidone (mean 9.2 months). The median annual costs for patients using ziprasidone included in the hypothetical cohort was 194,766.6 Mexican pesos (MXP) (95% CI, 26,515.6-363,017.6 MXP), with an exchange rate of 1 € = 17.36 MXP. The highest costs in the probabilistic analysis were estimated for clozapine treatment (260,236.9 MXP). Through a probabilistic analysis, ziprasidone showed the lowest costs and the highest number of months free of psychotic symptoms and was also the most costeffective antipsychotic observed in acceptability curves and net monetary benefits. Copyright © 2009 Sociedad Española de Psiquiatría and Sociedad Española de Psiquiatría Biológica. Published by Elsevier Espana. All rights reserved.

Cost-Effectiveness Analysis of Regorafenib for Metastatic Colorectal Cancer

PubMed Central

Goldstein, Daniel A.; Ahmad, Bilal B.; Chen, Qiushi; Ayer, Turgay; Howard, David H.; Lipscomb, Joseph; El-Rayes, Bassel F.; Flowers, Christopher R.

2015-01-01

Purpose Regorafenib is a standard-care option for treatment-refractory metastatic colorectal cancer that increases median overall survival by 6 weeks compared with placebo. Given this small incremental clinical benefit, we evaluated the cost-effectiveness of regorafenib in the third-line setting for patients with metastatic colorectal cancer from the US payer perspective. Methods We developed a Markov model to compare the cost and effectiveness of regorafenib with those of placebo in the third-line treatment of metastatic colorectal cancer. Health outcomes were measured in life-years and quality-adjusted life-years (QALYs). Drug costs were based on Medicare reimbursement rates in 2014. Model robustness was addressed in univariable and probabilistic sensitivity analyses. Results Regorafenib provided an additional 0.04 QALYs (0.13 life-years) at a cost of $40,000, resulting in an incremental cost-effectiveness ratio of $900,000 per QALY. The incremental cost-effectiveness ratio for regorafenib was > $550,000 per QALY in all of our univariable and probabilistic sensitivity analyses. Conclusion Regorafenib provides minimal incremental benefit at high incremental cost per QALY in the third-line management of metastatic colorectal cancer. The cost-effectiveness of regorafenib could be improved by the use of value-based pricing. PMID:26304904

Cost-effectiveness analysis of EGFR mutation testing in patients with non-small cell lung cancer (NSCLC) with gefitinib or carboplatin-paclitaxel.

PubMed

Arrieta, Oscar; Anaya, Pablo; Morales-Oyarvide, Vicente; Ramírez-Tirado, Laura Alejandra; Polanco, Ana C

2016-09-01

Assess the cost-effectiveness of an EGFR-mutation testing strategy for advanced NSCLC in first-line therapy with either gefitinib or carboplatin-paclitaxel in Mexican institutions. Cost-effectiveness analysis using a discrete event simulation (DES) model to simulate two therapeutic strategies in patients with advanced NSCLC. Strategy one included patients tested for EGFR-mutation and therapy given accordingly. Strategy two included chemotherapy for all patients without testing. All results are presented in 2014 US dollars. The analysis was made with data from the Mexican frequency of EGFR-mutation. A univariate sensitivity analysis was conducted on EGFR prevalence. Progression-free survival (PFS) transition probabilities were estimated on data from the IPASS and simulated with a Weibull distribution, run with parallel trials to calculate a probabilistic sensitivity analysis. PFS of patients in the testing strategy was 6.76 months (95 % CI 6.10-7.44) vs 5.85 months (95 % CI 5.43-6.29) in the non-testing group. The one-way sensitivity analysis showed that PFS has a direct relationship with EGFR-mutation prevalence, while the ICER and testing cost have an inverse relationship with EGFR-mutation prevalence. The probabilistic sensitivity analysis showed that all iterations had incremental costs and incremental PFS for strategy 1 in comparison with strategy 2. There is a direct relationship between the ICER and the cost of EGFR testing, with an inverse relationship with the prevalence of EGFR-mutation. When prevalence is >10 % ICER remains constant. This study could impact Mexican and Latin American health policies regarding mutation detection testing and treatment for advanced NSCLC.

Cost-Effectiveness of Pertuzumab in Human Epidermal Growth Factor Receptor 2–Positive Metastatic Breast Cancer

PubMed Central

Qian, Yushen; Pollom, Erqi L.; King, Martin T.; Dudley, Sara A.; Shaffer, Jenny L.; Chang, Daniel T.; Gibbs, Iris C.; Goldhaber-Fiebert, Jeremy D.; Horst, Kathleen C.

2016-01-01

Purpose The Clinical Evaluation of Pertuzumab and Trastuzumab (CLEOPATRA) study showed a 15.7-month survival benefit with the addition of pertuzumab to docetaxel and trastuzumab (THP) as first-line treatment for patients with human epidermal growth factor receptor 2 (HER2) –overexpressing metastatic breast cancer. We performed a cost-effectiveness analysis to assess the value of adding pertuzumab. Patient and Methods We developed a decision-analytic Markov model to evaluate the cost effectiveness of docetaxel plus trastuzumab (TH) with or without pertuzumab in US patients with metastatic breast cancer. The model followed patients weekly over their remaining lifetimes. Health states included stable disease, progressing disease, hospice, and death. Transition probabilities were based on the CLEOPATRA study. Costs reflected the 2014 Medicare rates. Health state utilities were the same as those used in other recent cost-effectiveness studies of trastuzumab and pertuzumab. Outcomes included health benefits expressed as discounted quality-adjusted life-years (QALYs), costs in US dollars, and cost effectiveness expressed as an incremental cost-effectiveness ratio. One- and multiway deterministic and probabilistic sensitivity analyses explored the effects of specific assumptions. Results Modeled median survival was 39.4 months for TH and 56.9 months for THP. The addition of pertuzumab resulted in an additional 1.81 life-years gained, or 0.62 QALYs, at a cost of $472,668 per QALY gained. Deterministic sensitivity analysis showed that THP is unlikely to be cost effective even under the most favorable assumptions, and probabilistic sensitivity analysis predicted 0% chance of cost effectiveness at a willingness to pay of $100,000 per QALY gained. Conclusion THP in patients with metastatic HER2-positive breast cancer is unlikely to be cost effective in the United States. PMID:26351332

Probabilistic Analysis of Solid Oxide Fuel Cell Based Hybrid Gas Turbine System

NASA Technical Reports Server (NTRS)

Gorla, Rama S. R.; Pai, Shantaram S.; Rusick, Jeffrey J.

2003-01-01

The emergence of fuel cell systems and hybrid fuel cell systems requires the evolution of analysis strategies for evaluating thermodynamic performance. A gas turbine thermodynamic cycle integrated with a fuel cell was computationally simulated and probabilistically evaluated in view of the several uncertainties in the thermodynamic performance parameters. Cumulative distribution functions and sensitivity factors were computed for the overall thermal efficiency and net specific power output due to the uncertainties in the thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design and make it cost effective. The analysis leads to the selection of criteria for gas turbine performance.

Design for Reliability and Safety Approach for the New NASA Launch Vehicle

NASA Technical Reports Server (NTRS)

Safie, Fayssal M.; Weldon, Danny M.

2007-01-01

The United States National Aeronautics and Space Administration (NASA) is in the midst of a space exploration program intended for sending crew and cargo to the international Space Station (ISS), to the moon, and beyond. This program is called Constellation. As part of the Constellation program, NASA is developing new launch vehicles aimed at significantly increase safety and reliability, reduce the cost of accessing space, and provide a growth path for manned space exploration. Achieving these goals requires a rigorous process that addresses reliability, safety, and cost upfront and throughout all the phases of the life cycle of the program. This paper discusses the "Design for Reliability and Safety" approach for the NASA new launch vehicles, the ARES I and ARES V. Specifically, the paper addresses the use of an integrated probabilistic functional analysis to support the design analysis cycle and a probabilistic risk assessment (PRA) to support the preliminary design and beyond.

Probabilistic performance-based design for high performance control systems

NASA Astrophysics Data System (ADS)

Micheli, Laura; Cao, Liang; Gong, Yongqiang; Cancelli, Alessandro; Laflamme, Simon; Alipour, Alice

2017-04-01

High performance control systems (HPCS) are advanced damping systems capable of high damping performance over a wide frequency bandwidth, ideal for mitigation of multi-hazards. They include active, semi-active, and hybrid damping systems. However, HPCS are more expensive than typical passive mitigation systems, rely on power and hardware (e.g., sensors, actuators) to operate, and require maintenance. In this paper, a life cycle cost analysis (LCA) approach is proposed to estimate the economic benefit these systems over the entire life of the structure. The novelty resides in the life cycle cost analysis in the performance based design (PBD) tailored to multi-level wind hazards. This yields a probabilistic performance-based design approach for HPCS. Numerical simulations are conducted on a building located in Boston, MA. LCA are conducted for passive control systems and HPCS, and the concept of controller robustness is demonstrated. Results highlight the promise of the proposed performance-based design procedure.

[Evaluation of the cost-effectiveness of two alternative human papillomavirus vaccines as prophylaxis against uterine cervical cancer].

PubMed

Bolaños-Díaz, Rafael; Tejada, Romina A; Beltrán, Jessica; Escobedo-Palza, Seimer

2016-01-01

To determine the cost-effectiveness of human papillomavirus (HPV) vaccination and cervical lesion screening versus screening alone for the prevention of uterine cervical cancer (UCC). This cost-effectiveness evaluation from the perspective of the Ministry of Health employed a Markov model with a 70-year time horizon and three alternatives for UCC prevention (screening alone, screening + bivalent vaccine, and screening + quadrivalent vaccine) in a hypothetical cohort of 10-year-old girls. Our model, which was particularly sensitive to variations in coverage and in the prevalence of persistent infection by oncologic genotypes not included in the vaccine, revealed that HPV vaccination and screening is more cost-effective than screening alone, assuming a payment availability from S/ 2 000 (US dollars (USD) 1 290.32) per subject. In the deterministic analysis, the bivalent vaccine was marginally more cost-effective than the quadrivalent vaccine (S/ 48 [USD 30.97] vs. S/ 166 [USD 107.10] per quality-adjusted life-year, respectively). However, in the probabilistic analysis, both interventions generated clouds of overlapping points and were thus cost-effective and interchangeable, although the quadrivalent vaccine tended to be more cost-effective. Assuming a payment availability from S/ 2000 [USD 1,290.32], screening and vaccination were more cost-effective than screening alone. The difference in cost-effectiveness between the two vaccines lacked probabilistic robustness, and therefore the vaccines can be considered interchangeable from a cost-effectiveness perspective.

Cost-Effectiveness Analysis of Probiotic Use to Prevent Clostridium difficile Infection in Hospitalized Adults Receiving Antibiotics.

PubMed

Shen, Nicole T; Leff, Jared A; Schneider, Yecheskel; Crawford, Carl V; Maw, Anna; Bosworth, Brian; Simon, Matthew S

2017-01-01

Systematic reviews with meta-analyses and meta-regression suggest that timely probiotic use can prevent Clostridium difficile infection (CDI) in hospitalized adults receiving antibiotics, but the cost effectiveness is unknown. We sought to evaluate the cost effectiveness of probiotic use for prevention of CDI versus no probiotic use in the United States. We programmed a decision analytic model using published literature and national databases with a 1-year time horizon. The base case was modeled as a hypothetical cohort of hospitalized adults (mean age 68) receiving antibiotics with and without concurrent probiotic administration. Projected outcomes included quality-adjusted life-years (QALYs), costs (2013 US dollars), incremental cost-effectiveness ratios (ICERs; $/QALY), and cost per infection avoided. One-way, two-way, and probabilistic sensitivity analyses were conducted, and scenarios of different age cohorts were considered. The ICERs less than $100000 per QALY were considered cost effective. Probiotic use dominated (more effective and less costly) no probiotic use. Results were sensitive to probiotic efficacy (relative risk <0.73), the baseline risk of CDI (>1.6%), the risk of probiotic-associated bactermia/fungemia (<0.26%), probiotic cost (<$130), and age (>65). In probabilistic sensitivity analysis, at a willingness-to-pay threshold of $100000/QALY, probiotics were the optimal strategy in 69.4% of simulations. Our findings suggest that probiotic use may be a cost-effective strategy to prevent CDI in hospitalized adults receiving antibiotics age 65 or older or when the baseline risk of CDI exceeds 1.6%.

Medial compartment knee osteoarthritis: age-stratified cost-effectiveness of total knee arthroplasty, unicompartmental knee arthroplasty, and high tibial osteotomy.

PubMed

Smith, William B; Steinberg, Joni; Scholtes, Stefan; Mcnamara, Iain R

2017-03-01

To compare the age-based cost-effectiveness of total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), and high tibial osteotomy (HTO) for the treatment of medial compartment knee osteoarthritis (MCOA). A Markov model was used to simulate theoretical cohorts of patients 40, 50, 60, and 70 years of age undergoing primary TKA, UKA, or HTO. Costs and outcomes associated with initial and subsequent interventions were estimated by following these virtual cohorts over a 10-year period. Revision and mortality rates, costs, and functional outcome data were estimated from a systematic review of the literature. Probabilistic analysis was conducted to accommodate these parameters' inherent uncertainty, and both discrete and probabilistic sensitivity analyses were utilized to assess the robustness of the model's outputs to changes in key variables. HTO was most likely to be cost-effective in cohorts under 60, and UKA most likely in those 60 and over. Probabilistic results did not indicate one intervention to be significantly more cost-effective than another. The model was exquisitely sensitive to changes in utility (functional outcome), somewhat sensitive to changes in cost, and least sensitive to changes in 10-year revision risk. HTO may be the most cost-effective option when treating MCOA in younger patients, while UKA may be preferred in older patients. Functional utility is the primary driver of the cost-effectiveness of these interventions. For the clinician, this study supports HTO as a competitive treatment option in young patient populations. It also validates each one of the three interventions considered as potentially optimal, depending heavily on patient preferences and functional utility derived over time.

Cost-effectiveness of noninvasive ventilation for chronic obstructive pulmonary disease-related respiratory failure in Indian hospitals without ICU facilities.

PubMed

Patel, Shraddha P; Pena, Margarita E; Babcock, Charlene Irvin

2015-01-01

The majority of Indian hospitals do not provide intensive care unit (ICU) care or ward-based noninvasive positive pressure ventilation (NIV). Because no mechanical ventilation or NIV is available in these hospitals, the majority of patients suffering from respiratory failure die. To perform a cost-effective analysis of two strategies (ward-based NIV with concurrent standard treatment vs standard treatment alone) in chronic obstructive pulmonary disease (COPD) respiratory failure patients treated in Indian hospitals without ICU care. A decision-analytical model was created to compare the cost-effectiveness for the two strategies. Estimates from the literature were used for parameters in the model. Future costs were discounted at 3%. All costs were reported in USD (2012). One-way, two-way, and probabilistic sensitivity analysis were performed. The time horizon was lifetime and perspective was societal. The NIV strategy resulted in 17.7% more survival and was slightly more costly (increased cost of $101 (USD 2012) but resulted in increased quality-adjusted life-years (QALYs) (1.67 QALY). The cost-effectiveness (2012 USD)/QALY in the standard and NIV groups was $78/QALY ($535.02/6.82) and $75/QALY ($636.33/8.49), respectively. Incremental cost-effectiveness ratio (ICER) was only $61 USD/QALY. This was substantially lower than the gross domestic product (GDP) per capita for India (1489 USD), suggesting the NIV strategy was very cost effective. Using a 5% discount rate resulted in only minimally different results. Probabilistic analysis suggests that NIV strategy was preferred 100% of the time when willingness to pay was >$250 2012 USD. Ward-based NIV treatment is cost-effective in India, and may increase survival of patients with COPD respiratory failure when ICU is not available.

Economic evaluation of the breast cancer screening programme in the Basque Country: retrospective cost-effectiveness and budget impact analysis.

PubMed

Arrospide, Arantzazu; Rue, Montserrat; van Ravesteyn, Nicolien T; Comas, Merce; Soto-Gordoa, Myriam; Sarriugarte, Garbiñe; Mar, Javier

2016-06-01

Breast cancer screening in the Basque Country has shown 20 % reduction of the number of BC deaths and an acceptable overdiagnosis level (4 % of screen detected BC). The aim of this study was to evaluate the breast cancer early detection programme in the Basque Country in terms of retrospective cost-effectiveness and budget impact from 1996 to 2011. A discrete event simulation model was built to reproduce the natural history of breast cancer (BC). We estimated for lifetime follow-up the total cost of BC (screening, diagnosis and treatment), as well as quality-adjusted life years (QALY), for women invited to participate in the evaluated programme during the 15-year period in the actual screening scenario and in a hypothetical unscreened scenario. An incremental cost-effectiveness ratio was calculated with the use of aggregated costs. Besides, annual costs were considered for budget impact analysis. Both population level and single-cohort analysis were performed. A probabilistic sensitivity analysis was applied to assess the impact of parameters uncertainty. The actual screening programme involved a cost of 1,127 million euros and provided 6.7 million QALYs over the lifetime of the target population, resulting in a gain of 8,666 QALYs for an additional cost of 36.4 million euros, compared with the unscreened scenario. Thus, the incremental cost-effectiveness ratio was 4,214€/QALY. All the model runs in the probabilistic sensitivity analysis resulted in an incremental cost-effectiveness ratio lower than 10,000€/QALY. The screening programme involved an increase of the annual budget of the Basque Health Service by 5.2 million euros from year 2000 onwards. The BC screening programme in the Basque Country proved to be cost-effective during the evaluated period and determined an affordable budget impact. These results confirm the epidemiological benefits related to the centralised screening system and support the continuation of the programme.

A cost-effectiveness analysis of a proactive management strategy for the Sprint Fidelis recall: a probabilistic decision analysis model.

PubMed

Bashir, Jamil; Cowan, Simone; Raymakers, Adam; Yamashita, Michael; Danter, Matthew; Krahn, Andrew; Lynd, Larry D

2013-12-01

The management of the recall is complicated by the competing risks of lead failure and complications that can occur with lead revision. Many of these patients are currently undergoing an elective generator change--an ideal time to consider lead revision. To determine the cost-effectiveness of a proactive management strategy for the Sprint Fidelis recall. We obtained detailed clinical outcomes and costing data from a retrospective analysis of 341 patients who received the Sprint Fidelis lead in British Columbia, where patients younger than 60 years were offered lead extraction when undergoing generator replacement. These population-based data were used to construct and populate a probabilistic Markov model in which a proactive management strategy was compared to a conservative strategy to determine the incremental cost per lead failure avoided. In our population, elective lead revisions were half the cost of emergent revisions and had a lower complication rate. In the model, the incremental cost-effectiveness ratio of proactive lead revision versus a recommended monitoring strategy was $12,779 per lead failure avoided. The proactive strategy resulted in 21 fewer failures per 100 patients treated and reduced the chance of an additional complication from an unexpected surgery. Cost-effectiveness analysis suggests that prospective lead revision should be considered when patients with a Sprint Fidelis lead present for pulse generator change. Elective revision of the lead is justified even when 25% of the population is operated on per year, and in some scenarios, it is both less costly and provides a better outcome. © 2013 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.

Probabilistic Structural Analysis Methods (PSAM) for select space propulsion system components, part 2

NASA Technical Reports Server (NTRS)

1991-01-01

The technical effort and computer code enhancements performed during the sixth year of the Probabilistic Structural Analysis Methods program are summarized. Various capabilities are described to probabilistically combine structural response and structural resistance to compute component reliability. A library of structural resistance models is implemented in the Numerical Evaluations of Stochastic Structures Under Stress (NESSUS) code that included fatigue, fracture, creep, multi-factor interaction, and other important effects. In addition, a user interface was developed for user-defined resistance models. An accurate and efficient reliability method was developed and was successfully implemented in the NESSUS code to compute component reliability based on user-selected response and resistance models. A risk module was developed to compute component risk with respect to cost, performance, or user-defined criteria. The new component risk assessment capabilities were validated and demonstrated using several examples. Various supporting methodologies were also developed in support of component risk assessment.

Cost-effectiveness of indacaterol/glycopyrronium in comparison with salmeterol/fluticasone combination for patients with moderate-to-severe chronic obstructive pulmonary disease: a LANTERN population analysis from Singapore.

PubMed

Tee, Augustine; Chow, Wai Leng; Burke, Colin; Basavarajaiah, Guruprasad

2018-03-16

In light of the growing evidence base for better clinical results with the use of the dual bronchodilator indacaterol/glycopyrronium (IND/GLY) over inhaled corticosteroid-containing salmeterol/fluticasone combination (SFC), this study aimed to evaluate the cost-effectiveness of IND/GLY over SFC in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) who are at low risk of exacerbations in the Singapore healthcare setting. A previously published patient-level simulation model was adapted for use in Singapore by applying local unit costs. The model was populated with clinical data from the LANTERN and ECLIPSE studies. Both costs and health outcomes were predicted for the lifetime horizon from a payer's perspective and were discounted at 3% per annum. Costs were expressed in 2015 USD. Uncertainty was assessed through probabilistic sensitivity analysis. Compared to SFC, use of IND/GLY increased mean life expectancy by 0.316 years and mean quality-adjusted life-years (QALYs) by 0.246 years, and decreased mean total treatment costs (drug costs and management of associated events) by USD 1,474 over the entire lifetime horizon. IND/GLY was considered to be 100% cost-effective at a threshold of 1 × gross domestic product per capita. The probabilistic sensitivity analysis results showed that IND/GLY was 100% cost-effective at a threshold of USD 2,000 when compared to SFC. IND/GLY was estimated to be highly cost-effective compared to SFC in patients with moderate-to-severe COPD who are not at high risk of exacerbations in the Singapore healthcare setting.

Cost-effectiveness analysis of implementing an antimicrobial stewardship program in critical care units.

PubMed

Ruiz-Ramos, Jesus; Frasquet, Juan; Romá, Eva; Poveda-Andres, Jose Luis; Salavert-Leti, Miguel; Castellanos, Alvaro; Ramirez, Paula

2017-06-01

To evaluate the cost-effectiveness of antimicrobial stewardship (AS) program implementation focused on critical care units based on assumptions for the Spanish setting. A decision model comparing costs and outcomes of sepsis, community-acquired pneumonia, and nosocomial infections (including catheter-related bacteremia, urinary tract infection, and ventilator-associated pneumonia) in critical care units with or without an AS was designed. Model variables and costs, along with their distributions, were obtained from the literature. The study was performed from the Spanish National Health System (NHS) perspective, including only direct costs. The Incremental Cost-Effectiveness Ratio (ICER) was analysed regarding the ability of the program to reduce multi-drug resistant bacteria. Uncertainty in ICERs was evaluated with probabilistic sensitivity analyses. In the short-term, implementing an AS reduces the consumption of antimicrobials with a net benefit of €71,738. In the long-term, the maintenance of the program involves an additional cost to the system of €107,569. Cost per avoided resistance was €7,342, and cost-per-life-years gained (LYG) was €9,788. Results from the probabilistic sensitivity analysis showed that there was a more than 90% likelihood that an AS would be cost-effective at a level of €8,000 per LYG. Wide variability of economic results obtained from the implementation of this type of AS program and short information on their impact on patient evolution and any resistance avoided. Implementing an AS focusing on critical care patients is a long-term cost-effective tool. Implementation costs are amortized by reducing antimicrobial consumption to prevent infection by multidrug-resistant pathogens.

Cost-Effectiveness of a Model Infection Control Program for Preventing Multi-Drug-Resistant Organism Infections in Critically Ill Surgical Patients.

PubMed

Jayaraman, Sudha P; Jiang, Yushan; Resch, Stephen; Askari, Reza; Klompas, Michael

2016-10-01

Interventions to contain two multi-drug-resistant Acinetobacter (MDRA) outbreaks reduced the incidence of multi-drug-resistant (MDR) organisms, specifically methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile in the general surgery intensive care unit (ICU) of our hospital. We therefore conducted a cost-effective analysis of a proactive model infection-control program to reduce transmission of MDR organisms based on the practices used to control the MDRA outbreak. We created a model of a proactive infection control program based on the 2011 MDRA outbreak response. We built a decision analysis model and performed univariable and probabilistic sensitivity analyses to evaluate the cost-effectiveness of the proposed program compared with standard infection control practices to reduce transmission of these MDR organisms. The cost of a proactive infection control program would be $68,509 per year. The incremental cost-effectiveness ratio (ICER) was calculated to be $3,804 per aversion of transmission of MDR organisms in a one-year period compared with standard infection control. On the basis of probabilistic sensitivity analysis, a willingness-to-pay (WTP) threshold of $14,000 per transmission averted would have a 42% probability of being cost-effective, rising to 100% at $22,000 per transmission averted. This analysis gives an estimated ICER for implementing a proactive program to prevent transmission of MDR organisms in the general surgery ICU. To better understand the causal relations between the critical steps in the program and the rate reductions, a randomized study of a package of interventions to prevent healthcare-associated infections should be considered.

The Role of Probabilistic Design Analysis Methods in Safety and Affordability

NASA Technical Reports Server (NTRS)

Safie, Fayssal M.

2016-01-01

For the last several years, NASA and its contractors have been working together to build space launch systems to commercialize space. Developing commercial affordable and safe launch systems becomes very important and requires a paradigm shift. This paradigm shift enforces the need for an integrated systems engineering environment where cost, safety, reliability, and performance need to be considered to optimize the launch system design. In such an environment, rule based and deterministic engineering design practices alone may not be sufficient to optimize margins and fault tolerance to reduce cost. As a result, introduction of Probabilistic Design Analysis (PDA) methods to support the current deterministic engineering design practices becomes a necessity to reduce cost without compromising reliability and safety. This paper discusses the importance of PDA methods in NASA's new commercial environment, their applications, and the key role they can play in designing reliable, safe, and affordable launch systems. More specifically, this paper discusses: 1) The involvement of NASA in PDA 2) Why PDA is needed 3) A PDA model structure 4) A PDA example application 5) PDA link to safety and affordability.

Cost-Effectiveness Analysis of Elective Neck Dissection in Patients With Clinically Node-Negative Oral Cavity Cancer.

PubMed

Acevedo, Joseph R; Fero, Katherine E; Wilson, Bayard; Sacco, Assuntina G; Mell, Loren K; Coffey, Charles S; Murphy, James D

2016-11-10

Purpose Recently, a large randomized trial found a survival advantage among patients who received elective neck dissection in conjunction with primary surgery for clinically node-negative oral cavity cancer compared with those receiving primary surgery alone. However, elective neck dissection comes with greater upfront cost and patient morbidity. We present a cost-effectiveness analysis of elective neck dissection for the initial surgical management of early-stage oral cavity cancer. Methods We constructed a Markov model to simulate primary, adjuvant, and salvage therapy; disease recurrence; and survival in patients with T1/T2 clinically node-negative oral cavity squamous cell carcinoma. Transition probabilities were derived from clinical trial data; costs (in 2015 US dollars) and health utilities were estimated from the literature. Incremental cost-effectiveness ratios, expressed as dollar per quality-adjusted life-year (QALY), were calculated with incremental cost-effectiveness ratios less than $100,000/QALY considered cost effective. We conducted one-way and probabilistic sensitivity analyses to examine model uncertainty. Results Our base-case model found that over a lifetime the addition of elective neck dissection to primary surgery reduced overall costs by $6,000 and improved effectiveness by 0.42 QALYs compared with primary surgery alone. The decrease in overall cost despite the added neck dissection was a result of less use of salvage therapy. On one-way sensitivity analysis, the model was most sensitive to assumptions about disease recurrence, survival, and the health utility reduction from a neck dissection. Probabilistic sensitivity analysis found that treatment with elective neck dissection was cost effective 76% of the time at a willingness-to-pay threshold of $100,000/QALY. Conclusion Our study found that the addition of elective neck dissection reduces costs and improves health outcomes, making this a cost-effective treatment strategy for patients with early-stage oral cavity cancer.

Cost effectiveness of a pharmacist-led information technology intervention for reducing rates of clinically important errors in medicines management in general practices (PINCER).

PubMed

Elliott, Rachel A; Putman, Koen D; Franklin, Matthew; Annemans, Lieven; Verhaeghe, Nick; Eden, Martin; Hayre, Jasdeep; Rodgers, Sarah; Sheikh, Aziz; Avery, Anthony J

2014-06-01

We recently showed that a pharmacist-led information technology-based intervention (PINCER) was significantly more effective in reducing medication errors in general practices than providing simple feedback on errors, with cost per error avoided at £79 (US$131). We aimed to estimate cost effectiveness of the PINCER intervention by combining effectiveness in error reduction and intervention costs with the effect of the individual errors on patient outcomes and healthcare costs, to estimate the effect on costs and QALYs. We developed Markov models for each of six medication errors targeted by PINCER. Clinical event probability, treatment pathway, resource use and costs were extracted from literature and costing tariffs. A composite probabilistic model combined patient-level error models with practice-level error rates and intervention costs from the trial. Cost per extra QALY and cost-effectiveness acceptability curves were generated from the perspective of NHS England, with a 5-year time horizon. The PINCER intervention generated £2,679 less cost and 0.81 more QALYs per practice [incremental cost-effectiveness ratio (ICER): -£3,037 per QALY] in the deterministic analysis. In the probabilistic analysis, PINCER generated 0.001 extra QALYs per practice compared with simple feedback, at £4.20 less per practice. Despite this extremely small set of differences in costs and outcomes, PINCER dominated simple feedback with a mean ICER of -£3,936 (standard error £2,970). At a ceiling 'willingness-to-pay' of £20,000/QALY, PINCER reaches 59 % probability of being cost effective. PINCER produced marginal health gain at slightly reduced overall cost. Results are uncertain due to the poor quality of data to inform the effect of avoiding errors.

Optimization of monitoring and inspections in the life-cycle of wind turbines

NASA Astrophysics Data System (ADS)

Hanish Nithin, Anu; Omenzetter, Piotr

2016-04-01

The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

Economic evaluation of floseal compared to nasal packing for the management of anterior epistaxis.

PubMed

Le, Andre; Thavorn, Kednapa; Lasso, Andrea; Kilty, Shaun J

2018-01-04

To evaluate the cost-effectiveness of Floseal, a topically applied hemostatic agent, and nasal packing for the management of epistaxis in Canada. Outcomes research, a cost-utility analysis. We developed a Markov model to compare the costs and health outcomes of Floseal with nasal packing over a lifetime horizon from the perspective of a publicly funded healthcare system. A cycle length of 1 year was used. Efficacy of Floseal and packing was sought from the published literature. Unit costs were gathered from a hospital case costing system, whereas physician fees were extracted from the Ontario Schedule of Benefits for Physician Services. Results were expressed as an incremental cost per quality-adjusted life year (QALY) gained. A series of one-way sensitivity and probabilistic sensitivity analyses were performed. From the perspective of a publicly funded health are system, the Floseal treatment strategy was associated with higher costs ($2,067) and greater QALYs (0.27) than nasal packing. Our findings were highly sensitive to discount rates, the cost of Floseal, and the cost of nasal packing. The probabilistic sensitivity analysis suggested that the probability that Floseal treatment is cost-effective reached 99% if the willingness-to-pay threshold was greater than $120,000 per QALY gained. Prior studies have demonstrated Floseal to be an effective treatment for anterior epistaxis. In the Canadian healthcare system, Floseal treatment appears to be a cost-effective treatment option compared to nasal packing for anterior epistaxis. 2c Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

Illustrating economic evaluation of diagnostic technologies: comparing Helicobacter pylori screening strategies in prevention of gastric cancer in Canada.

PubMed

Xie, Feng; O'Reilly, Daria; Ferrusi, Ilia L; Blackhouse, Gord; Bowen, James M; Tarride, Jean-Eric; Goeree, Ron

2009-05-01

The aim of this paper is to present an economic evaluation of diagnostic technologies using Helicobacter pylori screening strategies for the prevention of gastric cancer as an illustration. A Markov model was constructed to compare the lifetime cost and effectiveness of 4 potential strategies: no screening, the serology test by enzyme-linked immunosorbent assay (ELISA), the stool antigen test (SAT), and the (13)C-urea breath test (UBT) for the detection of H. pylori among a hypothetical cohort of 10,000 Canadian men aged 35 years. Special parameter consideration included the sensitivity and specificity of each screening strategy, which determined the model structure and treatment regimen. The primary outcome measured was the incremental cost-effectiveness ratio between the screening strategies and the no-screening strategy. Base-case analysis and probabilistic sensitivity analysis were performed using the point estimates of the parameters and Monte Carlo simulations, respectively. Compared with the no-screening strategy in the base-case analysis, the incremental cost-effectiveness ratio was $33,000 per quality-adjusted life-year (QALY) for the ELISA, $29,800 per QALY for the SAT, and $50,400 per QALY for the UBT. The probabilistic sensitivity analysis revealed that the no-screening strategy was more cost effective if the willingness to pay (WTP) was <$20,000 per QALY, while the SAT had the highest probability of being cost effective if the WTP was >$30,000 per QALY. Both the ELISA and the UBT were not cost-effective strategies over a wide range of WTP values. Although the UBT had the highest sensitivity and specificity, either no screening or the SAT could be the most cost-effective strategy depending on the WTP threshold values from an economic perspective. This highlights the importance of economic evaluations of diagnostic technologies.

Economic evaluation of rivaroxaban in stroke prevention for patients with atrial fibrillation in Greece

PubMed Central

2014-01-01

Background To undertake an economic evaluation of rivaroxaban relative to the standard of care for stroke prevention in patients with non-valvular atrial fibrillation (AF) in Greece. Methods An existing Markov model designed to reflect the natural progression of AF patients through different health states, in the course of three month cycles, was adapted to the Greek setting. The analysis was undertaken from a payer perspective. Baseline event rates and efficacy data were obtained from the ROCKET-AF trial for rivaroxaban and vitamin-K-antagonists (VKAs). Utility values for events were based on literature. A treatment-related disutility of 0.05 was applied to the VKA arm. Costs assigned to each health state reflect the year 2013. An incremental cost effectiveness ratio (ICER) was calculated where the outcome was quality-adjusted-life year (QALY) and life-years gained. Probabilistic analysis was undertaken to deal with uncertainty. The horizon of analysis was over patient life time and both cost and outcomes were discounted at 3.5%. Results Based on safety-on-treatment data, rivaroxaban was associated with a 0.22 increment in QALYs compared to VKA. The average total lifetime cost of rivaroxaban-treated patients was €239 lower compared to VKA. Rivaroxaban was associated with additional drug acquisition cost (€4,033) and reduced monitoring cost (-€3,929). Therefore, rivaroxaban was a dominant alternative over VKA. Probabilistic analysis revealed that there is a 100% probability of rivaroxaban being cost-effective versus VKA at a willingness to pay threshold of €30,000/QALY gained. Conclusion Rivaroxaban may represent for payers a dominant option for the prevention of thromboembolic events in moderate to high risk AF patients in Greece. PMID:24512351

Concurrent Probabilistic Simulation of High Temperature Composite Structural Response

NASA Technical Reports Server (NTRS)

Abdi, Frank

1996-01-01

A computational structural/material analysis and design tool which would meet industry's future demand for expedience and reduced cost is presented. This unique software 'GENOA' is dedicated to parallel and high speed analysis to perform probabilistic evaluation of high temperature composite response of aerospace systems. The development is based on detailed integration and modification of diverse fields of specialized analysis techniques and mathematical models to combine their latest innovative capabilities into a commercially viable software package. The technique is specifically designed to exploit the availability of processors to perform computationally intense probabilistic analysis assessing uncertainties in structural reliability analysis and composite micromechanics. The primary objectives which were achieved in performing the development were: (1) Utilization of the power of parallel processing and static/dynamic load balancing optimization to make the complex simulation of structure, material and processing of high temperature composite affordable; (2) Computational integration and synchronization of probabilistic mathematics, structural/material mechanics and parallel computing; (3) Implementation of an innovative multi-level domain decomposition technique to identify the inherent parallelism, and increasing convergence rates through high- and low-level processor assignment; (4) Creating the framework for Portable Paralleled architecture for the machine independent Multi Instruction Multi Data, (MIMD), Single Instruction Multi Data (SIMD), hybrid and distributed workstation type of computers; and (5) Market evaluation. The results of Phase-2 effort provides a good basis for continuation and warrants Phase-3 government, and industry partnership.

Probabilistic sensitivity analysis for NICE technology assessment: not an optional extra.

PubMed

Claxton, Karl; Sculpher, Mark; McCabe, Chris; Briggs, Andrew; Akehurst, Ron; Buxton, Martin; Brazier, John; O'Hagan, Tony

2005-04-01

Recently the National Institute for Clinical Excellence (NICE) updated its methods guidance for technology assessment. One aspect of the new guidance is to require the use of probabilistic sensitivity analysis with all cost-effectiveness models submitted to the Institute. The purpose of this paper is to place the NICE guidance on dealing with uncertainty into a broader context of the requirements for decision making; to explain the general approach that was taken in its development; and to address each of the issues which have been raised in the debate about the role of probabilistic sensitivity analysis in general. The most appropriate starting point for developing guidance is to establish what is required for decision making. On the basis of these requirements, the methods and framework of analysis which can best meet these needs can then be identified. It will be argued that the guidance on dealing with uncertainty and, in particular, the requirement for probabilistic sensitivity analysis, is justified by the requirements of the type of decisions that NICE is asked to make. Given this foundation, the main issues and criticisms raised during and after the consultation process are reviewed. Finally, some of the methodological challenges posed by the need fully to characterise decision uncertainty and to inform the research agenda will be identified and discussed. Copyright (c) 2005 John Wiley & Sons, Ltd.

Cost-Utility Analysis: Sartorius Flap versus Negative Pressure Therapy for Infected Vascular Groin Graft Managment.

PubMed

Chatterjee, Abhishek; Macarios, David; Griffin, Leah; Kosowski, Tomasz; Pyfer, Bryan J; Offodile, Anaeze C; Driscoll, Daniel; Maddali, Sirish; Attwood, John

2015-11-01

Sartorius flap coverage and adjunctive negative pressure wound therapy (NPWT) have been described in managing infected vascular groin grafts with varying cost and clinical success. We performed a cost-utility analysis comparing sartorius flap with NPWT in managing an infected vascular groin graft. A literature review compiling outcomes for sartorius flap and NPWT interventions was conducted from peer-reviewed journals in MEDLINE (PubMed) and EMBASE. Utility scores were derived from expert opinion and used to estimate quality-adjusted life years (QALYs). Medicare current procedure terminology and diagnosis-related groups codes were used to assess the costs for successful graft salvage with the associated complications. Incremental cost-effectiveness was assessed at $50,000/QALY, and both univariate and probabilistic sensitivity analyses were conducted to assess robustness of the conclusions. Thirty-two studies were used pooling 384 patients (234 sartorius flaps and 150 NPWT). NPWT had better clinical outcomes (86.7% success rate, 0.9% minor complication rate, and 13.3% major complication rate) than sartorius flap (81.6% success rate, 8.0% minor complication rate, and 18.4% major complication rate). NPWT was less costly ($12,366 versus $23,516) and slightly more effective (12.06 QALY versus 12.05 QALY) compared with sartorius flap. Sensitivity analyses confirmed the robustness of the base case findings; NPWT was either cost-effective at $50,000/QALY or dominated sartorius flap in 81.6% of all probabilistic sensitivity analyses. In our cost-utility analysis, use of adjunctive NPWT, along with debridement and antibiotic treatment, for managing infected vascular groin graft wounds was found to be a more cost-effective option when compared with sartorius flaps.

Economic evaluation of everolimus versus sorafenib for the treatment of metastatic renal cell carcinoma after failure of first-line sunitinib.

PubMed

Casciano, Roman; Chulikavit, Maruit; Di Lorenzo, Giuseppe; Liu, Zhimei; Baladi, Jean-Francois; Wang, Xufang; Robertson, Justin; Garrison, Lou

2011-01-01

A recent indirect comparison study showed that sunitinib-refractory metastatic renal cell carcinoma (mRCC) patients treated with everolimus are expected to have improved overall survival outcomes compared to patients treated with sorafenib. This analysis examines the likely cost-effectiveness of everolimus versus sorafenib in this setting from a US payer perspective. A Markov model was developed to simulate a cohort of sunitinib-refractory mRCC patients and to estimate the cost per incremental life-years gained (LYG) and quality-adjusted life-years (QALYs) gained. Markov states included are stable disease without adverse events, stable disease with adverse events, disease progression, and death. Transition probabilities were estimated using a subset of the RECORD-1 patient population receiving everolimus after sunitinib, and a comparable population receiving sorafenib in a single-arm phase II study. Costs of antitumor therapies were based on wholesale acquisition cost. Health state costs accounted for physician visits, tests, adverse events, postprogression therapy, and end-of-life care. The model extrapolated beyond the trial time horizon for up to 6 years based on published trial data. Deterministic and probabilistic sensitivity analyses were conducted. The estimated gain over sorafenib treatment was 1.273 LYs (0.916 QALYs) at an incremental cost of $81,643. The deterministic analysis resulted in an incremental cost-effectiveness ratio (ICER) of $64,155/LYG ($89,160/QALY). The probabilistic sensitivity analysis demonstrated that results were highly consistent across simulations. As the ICER fell within the cost per QALY range for many other widely used oncology medicines, everolimus is projected to be a cost-effective treatment relative to sorafenib for sunitinib-refractory mRCC. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Cost-effectiveness of emergency versus delayed laparoscopic cholecystectomy for acute gallbladder pathology.

PubMed

Sutton, A J; Vohra, R S; Hollyman, M; Marriott, P J; Buja, A; Alderson, D; Pasquali, S; Griffiths, E A

2017-01-01

The optimal timing of cholecystectomy for patients admitted with acute gallbladder pathology is unclear. Some studies have shown that emergency cholecystectomy during the index admission can reduce length of hospital stay with similar rates of conversion to open surgery, complications and mortality compared with a 'delayed' operation following discharge. Others have reported that cholecystectomy during the index acute admission results in higher morbidity, extended length of stay and increased costs. This study examined the cost-effectiveness of emergency versus delayed cholecystectomy for acute benign gallbladder disease. Using data from a prospective population-based cohort study examining the outcomes of cholecystectomy in the UK and Ireland, a model-based cost-utility analysis was conducted from the perspective of the UK National Health Service, with a 1-year time horizon for costs and outcomes. Probabilistic sensitivity analysis was used to investigate the impact of parameter uncertainty on the results obtained from the model. Emergency cholecystectomy was found to be less costly (£4570 versus £4720; €5484 versus €5664) and more effective (0·8868 versus 0·8662 QALYs) than delayed cholecystectomy. Probabilistic sensitivity analysis showed that the emergency strategy is more than 60 per cent likely to be cost-effective across willingness-to-pay values for the QALY from £0 to £100 000 (€0-120 000). Emergency cholecystectomy is less costly and more effective than delayed cholecystectomy. This approach is likely to be beneficial to patients in terms of improved health outcomes and to the healthcare provider owing to the reduced costs. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

Cost-effectiveness analysis of ibrutinib in patients with Waldenström macroglobulinemia in Italy.

PubMed

Aiello, Andrea; D'Ausilio, Anna; Lo Muto, Roberta; Randon, Francesca; Laurenti, Luca

2017-01-01

Background and Objective: Ibrutinib has recently been approved in Europe for Waldenström Macroglobulinemia (WM) in symptomatic patients who have received at least one prior therapy, or in first-line treatment for patients unsuitable for chemo-immunotherapy. The aim of the study is to estimate the incremental cost-effectiveness ratio (ICER) of ibrutinib in relapse/refractory WM, compared with the Italian current therapeutic pathways (CTP). Methods: A Markov model was adapted for Italy considering the National Health System perspective. Input data from literature as well as global trials were used. The percentage use of therapies, and healthcare resources consumption were estimated according to expert panel advice. Drugs ex-factory prices and national tariffs were used for estimating costs. The model had a 15-year time horizon, with a 3.0% discount rate for both clinical and economic data. Deterministic and probabilistic sensitivity analyses were performed to test the results strength. Results: Ibrutinib resulted in increased Life Years Gained (LYGs) and increased costs compared to CTP, with an ICER of €52,698/LYG. Sensitivity analyses confirmed the results of the BaseCase. Specifically, in the probabilistic analysis, at a willingness to pay threshold of €60,000/LYG ibrutinib was cost-effective in 84% of simulations. Conclusions: Ibrutinib has demonstrated a positive cost-effectiveness profile in Italy.

Probabilistic Finite Element Analysis & Design Optimization for Structural Designs

NASA Astrophysics Data System (ADS)

Deivanayagam, Arumugam

This study focuses on implementing probabilistic nature of material properties (Kevlar® 49) to the existing deterministic finite element analysis (FEA) of fabric based engine containment system through Monte Carlo simulations (MCS) and implementation of probabilistic analysis in engineering designs through Reliability Based Design Optimization (RBDO). First, the emphasis is on experimental data analysis focusing on probabilistic distribution models which characterize the randomness associated with the experimental data. The material properties of Kevlar® 49 are modeled using experimental data analysis and implemented along with an existing spiral modeling scheme (SMS) and user defined constitutive model (UMAT) for fabric based engine containment simulations in LS-DYNA. MCS of the model are performed to observe the failure pattern and exit velocities of the models. Then the solutions are compared with NASA experimental tests and deterministic results. MCS with probabilistic material data give a good prospective on results rather than a single deterministic simulation results. The next part of research is to implement the probabilistic material properties in engineering designs. The main aim of structural design is to obtain optimal solutions. In any case, in a deterministic optimization problem even though the structures are cost effective, it becomes highly unreliable if the uncertainty that may be associated with the system (material properties, loading etc.) is not represented or considered in the solution process. Reliable and optimal solution can be obtained by performing reliability optimization along with the deterministic optimization, which is RBDO. In RBDO problem formulation, in addition to structural performance constraints, reliability constraints are also considered. This part of research starts with introduction to reliability analysis such as first order reliability analysis, second order reliability analysis followed by simulation technique that are performed to obtain probability of failure and reliability of structures. Next, decoupled RBDO procedure is proposed with a new reliability analysis formulation with sensitivity analysis, which is performed to remove the highly reliable constraints in the RBDO, thereby reducing the computational time and function evaluations. Followed by implementation of the reliability analysis concepts and RBDO in finite element 2D truss problems and a planar beam problem are presented and discussed.

Cost-Effectiveness Analysis of Probiotic Use to Prevent Clostridium difficile Infection in Hospitalized Adults Receiving Antibiotics

PubMed Central

Leff, Jared A; Schneider, Yecheskel; Crawford, Carl V; Maw, Anna; Bosworth, Brian; Simon, Matthew S

2017-01-01

Abstract Background Systematic reviews with meta-analyses and meta-regression suggest that timely probiotic use can prevent Clostridium difficile infection (CDI) in hospitalized adults receiving antibiotics, but the cost effectiveness is unknown. We sought to evaluate the cost effectiveness of probiotic use for prevention of CDI versus no probiotic use in the United States. Methods We programmed a decision analytic model using published literature and national databases with a 1-year time horizon. The base case was modeled as a hypothetical cohort of hospitalized adults (mean age 68) receiving antibiotics with and without concurrent probiotic administration. Projected outcomes included quality-adjusted life-years (QALYs), costs (2013 US dollars), incremental cost-effectiveness ratios (ICERs; $/QALY), and cost per infection avoided. One-way, two-way, and probabilistic sensitivity analyses were conducted, and scenarios of different age cohorts were considered. The ICERs less than $100000 per QALY were considered cost effective. Results Probiotic use dominated (more effective and less costly) no probiotic use. Results were sensitive to probiotic efficacy (relative risk <0.73), the baseline risk of CDI (>1.6%), the risk of probiotic-associated bactermia/fungemia (<0.26%), probiotic cost (<$130), and age (>65). In probabilistic sensitivity analysis, at a willingness-to-pay threshold of $100000/QALY, probiotics were the optimal strategy in 69.4% of simulations. Conclusions Our findings suggest that probiotic use may be a cost-effective strategy to prevent CDI in hospitalized adults receiving antibiotics age 65 or older or when the baseline risk of CDI exceeds 1.6%. PMID:29230429

Probabilistic framework for product design optimization and risk management

NASA Astrophysics Data System (ADS)

Keski-Rahkonen, J. K.

2018-05-01

Probabilistic methods have gradually gained ground within engineering practices but currently it is still the industry standard to use deterministic safety margin approaches to dimensioning components and qualitative methods to manage product risks. These methods are suitable for baseline design work but quantitative risk management and product reliability optimization require more advanced predictive approaches. Ample research has been published on how to predict failure probabilities for mechanical components and furthermore to optimize reliability through life cycle cost analysis. This paper reviews the literature for existing methods and tries to harness their best features and simplify the process to be applicable in practical engineering work. Recommended process applies Monte Carlo method on top of load-resistance models to estimate failure probabilities. Furthermore, it adds on existing literature by introducing a practical framework to use probabilistic models in quantitative risk management and product life cycle costs optimization. The main focus is on mechanical failure modes due to the well-developed methods used to predict these types of failures. However, the same framework can be applied on any type of failure mode as long as predictive models can be developed.

Using probabilistic terrorism risk modeling for regulatory benefit-cost analysis: application to the Western hemisphere travel initiative in the land environment.

PubMed

Willis, Henry H; LaTourrette, Tom

2008-04-01

This article presents a framework for using probabilistic terrorism risk modeling in regulatory analysis. We demonstrate the framework with an example application involving a regulation under consideration, the Western Hemisphere Travel Initiative for the Land Environment, (WHTI-L). First, we estimate annualized loss from terrorist attacks with the Risk Management Solutions (RMS) Probabilistic Terrorism Model. We then estimate the critical risk reduction, which is the risk-reducing effectiveness of WHTI-L needed for its benefit, in terms of reduced terrorism loss in the United States, to exceed its cost. Our analysis indicates that the critical risk reduction depends strongly not only on uncertainties in the terrorism risk level, but also on uncertainty in the cost of regulation and how casualties are monetized. For a terrorism risk level based on the RMS standard risk estimate, the baseline regulatory cost estimate for WHTI-L, and a range of casualty cost estimates based on the willingness-to-pay approach, our estimate for the expected annualized loss from terrorism ranges from $2.7 billion to $5.2 billion. For this range in annualized loss, the critical risk reduction for WHTI-L ranges from 7% to 13%. Basing results on a lower risk level that results in halving the annualized terrorism loss would double the critical risk reduction (14-26%), and basing the results on a higher risk level that results in a doubling of the annualized terrorism loss would cut the critical risk reduction in half (3.5-6.6%). Ideally, decisions about terrorism security regulations and policies would be informed by true benefit-cost analyses in which the estimated benefits are compared to costs. Such analyses for terrorism security efforts face substantial impediments stemming from the great uncertainty in the terrorist threat and the very low recurrence interval for large attacks. Several approaches can be used to estimate how a terrorism security program or regulation reduces the distribution of risks it is intended to manage. But, continued research to develop additional tools and data is necessary to support application of these approaches. These include refinement of models and simulations, engagement of subject matter experts, implementation of program evaluation, and estimating the costs of casualties from terrorism events.

Cost Effectiveness of Free Access to Smoking Cessation Treatment in France Considering the Economic Burden of Smoking-Related Diseases.

PubMed

Cadier, Benjamin; Durand-Zaleski, Isabelle; Thomas, Daniel; Chevreul, Karine

2016-01-01

In France more than 70,000 deaths from diseases related to smoking are recorded each year, and since 2005 prevalence of tobacco has increased. Providing free access to smoking cessation treatment would reduce this burden. The aim of our study was to estimate the incremental cost-effectiveness ratios (ICER) of providing free access to cessation treatment taking into account the cost offsets associated with the reduction of the three main diseases related to smoking: lung cancer, chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). To measure the financial impact of such a measure we also conducted a probabilistic budget impact analysis. We performed a cost-effectiveness analysis using a Markov state-transition model that compared free access to cessation treatment to the existing coverage of €50 provided by the French statutory health insurance, taking into account the cost offsets among current French smokers aged 15-75 years. Our results were expressed by the incremental cost-effectiveness ratio in 2009 Euros per life year gained (LYG) at the lifetime horizon. We estimated a base case scenario and carried out a Monte Carlo sensitivity analysis to account for uncertainty. Assuming a participation rate of 7.3%, the ICER value for free access to cessation treatment was €3,868 per LYG in the base case. The variation of parameters provided a range of ICER values from -€736 to €15,715 per LYG. In 99% of cases, the ICER for full coverage was lower than €11,187 per LYG. The probabilistic budget impact analysis showed that the potential cost saving for lung cancer, COPD and CVD ranges from €15 million to €215 million at the five-year horizon for an initial cessation treatment cost of €125 million to €421 million. The results suggest that providing medical support to smokers in their attempts to quit is very cost-effective and may even result in cost savings.

Pharmacoeconomic Analysis of Pain Medications Used to Treat Adult Patients with Chronic Back Pain in the United States.

PubMed

Shah, Drishti; Anupindi, Vamshi Ruthwik; Vaidya, Varun

2016-12-01

Chronic back pain is an extremely common health problem. The largest category for pain therapy costs includes nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids. However, there has been limited evidence outlining their effectiveness in terms of quality of life for the treatment of chronic back pain. The authors performed a comparative pharmacoeconomic analysis of chronic back pain patients using NSAIDs versus those using opioids alone or combination opioid analgesics. This pharmacoeconomic evaluation was conducted using the Medical Expenditure Panel Survey (MEPS). Adults ≥18 years with chronic back pain diagnosis were included in the study. Individuals using opioids were matched in 1:1 ratio with those using only NSAIDs using propensity scores. All direct medical costs were included, and utility scores from Short Form 6D (SF-6D) were used to calculate QALYs (quality-adjusted life years). Monte Carlo probabilistic simulation technique was employed to determine the cost-effectiveness acceptability curve. After matching, there were 1109 patients in each cohort. The total mean annual cost was found to be $6137.41 for NSAIDs and $8982.28 for opioids. The mean utility gain for NSAIDs was found to be 0.661, whereas for opioids it was 0.633. Probabilistic sensitivity analysis showed that at all willingness-to-pay thresholds, the probability of NSAIDs being cost-effective was higher than the probability of the opioids being cost-effective. The authors found NSAIDs to be a dominant strategy as compared with opioids. Considering the higher cost associated with opioids/combination opioid analgesics, it might be cost-effective if they are used in patients who did not respond to the NSAIDs.

Supraorbital Versus Endoscopic Endonasal Approaches for Olfactory Groove Meningiomas: A Cost-Minimization Study.

PubMed

Gandhoke, Gurpreet S; Pease, Matthew; Smith, Kenneth J; Sekula, Raymond F

2017-09-01

To perform a cost-minimization study comparing the supraorbital and endoscopic endonasal (EEA) approach with or without craniotomy for the resection of olfactory groove meningiomas (OGMs). We built a decision tree using probabilities of gross total resection (GTR) and cerebrospinal fluid (CSF) leak rates with the supraorbital approach versus EEA with and without additional craniotomy. The cost (not charge or reimbursement) at each "stem" of this decision tree for both surgical options was obtained from our hospital's finance department. After a base case calculation, we applied plausible ranges to all parameters and carried out multiple 1-way sensitivity analyses. Probabilistic sensitivity analyses confirmed our results. The probabilities of GTR (0.8) and CSF leak (0.2) for the supraorbital craniotomy were obtained from our series of 5 patients who underwent a supraorbital approach for the resection of an OGM. The mean tumor volume was 54.6 cm 3 (range, 17-94.2 cm 3 ). Literature-reported rates of GTR (0.6) and CSF leak (0.3) with EEA were applied to our economic analysis. Supraorbital craniotomy was the preferred strategy, with an expected value of $29,423, compared with an EEA cost of $83,838. On multiple 1-way sensitivity analyses, supraorbital craniotomy remained the preferred strategy, with a minimum cost savings of $46,000 and a maximum savings of $64,000. Probabilistic sensitivity analysis found the lowest cost difference between the 2 surgical options to be $37,431. Compared with EEA, supraorbital craniotomy provides substantial cost savings in the treatment of OGMs. Given the potential differences in effectiveness between approaches, a cost-effectiveness analysis should be undertaken. Copyright © 2017 Elsevier Inc. All rights reserved.

Latest NASA Instrument Cost Model (NICM): Version VI

NASA Technical Reports Server (NTRS)

Mrozinski, Joe; Habib-Agahi, Hamid; Fox, George; Ball, Gary

2014-01-01

The NASA Instrument Cost Model, NICM, is a suite of tools which allow for probabilistic cost estimation of NASA's space-flight instruments at both the system and subsystem level. NICM also includes the ability to perform cost by analogy as well as joint confidence level (JCL) analysis. The latest version of NICM, Version VI, was released in Spring 2014. This paper will focus on the new features released with NICM VI, which include: 1) The NICM-E cost estimating relationship, which is applicable for instruments flying on Explorer-like class missions; 2) The new cluster analysis ability which, alongside the results of the parametric cost estimation for the user's instrument, also provides a visualization of the user's instrument's similarity to previously flown instruments; and 3) includes new cost estimating relationships for in-situ instruments.

Cost effectiveness of a telephone intervention to promote dilated fundus examination in adults with diabetes mellitus

PubMed Central

Schechter, Clyde B; Basch, Charles E; Caban, Arlene; Walker, Elizabeth A

2008-01-01

In a clinical trial, we have previously shown that a telephone intervention can significantly increase participation in dilated fundus examination (DFE) screening among low-income adults with diabetes. Here the costs and cost-effectiveness ratio of this intervention are calculated. Intervention effectiveness was estimated as the difference in DFE utilization between the telephone intervention and print groups from the clinical trial multiplied by the size of the telephone intervention group. A micro-costing approach was used. Personnel time was aggregated from logs kept during the clinical trial of the intervention. Wage rates were taken from a commercial compensation database. Telephone charges were estimated based on prevailing fees. The cost-effectiveness ratio was calculated as the ratio of total costs of the intervention to the number of DFEs gained by the intervention. A sensitivity analysis estimated the cost-effectiveness of a more limited telephone intervention. A probabilistic sensitivity analysis using bootstrap samples from the clinical trial results quantified the uncertainties in resource utilization and intervention effectiveness. Net intervention costs were US$18,676.06, with an associated gain of 43.7 DFEs and 16.4 new diagnoses of diabetic retinopathy. The cost-effectiveness ratio is US$427.37 per DFE gained. A restricted intervention limiting the number of calls to 5, as opposed to 7, would achieve the same results, but would cost approximately 17% less. In the probabilistic sensitivity analysis, the 5th and 95th percentiles of the cost-effectiveness ratio were US$304.05 and US$692.52 per DFE gained, respectively. Our telephone intervention is more expensive than simple mail or telephone reminders used in other settings to promote preventive care; it is, however, also considerably more effective, and is effective in a low-income minority population at greater risk for diabetes complications. The costs are dominated by labor costs, and may be substantially defrayed, without loss of effectiveness, by restricting the number of telephone calls to 5 per patient. PMID:19668428

Uncertainty characterization approaches for risk assessment of DBPs in drinking water: a review.

PubMed

Chowdhury, Shakhawat; Champagne, Pascale; McLellan, P James

2009-04-01

The management of risk from disinfection by-products (DBPs) in drinking water has become a critical issue over the last three decades. The areas of concern for risk management studies include (i) human health risk from DBPs, (ii) disinfection performance, (iii) technical feasibility (maintenance, management and operation) of treatment and disinfection approaches, and (iv) cost. Human health risk assessment is typically considered to be the most important phase of the risk-based decision-making or risk management studies. The factors associated with health risk assessment and other attributes are generally prone to considerable uncertainty. Probabilistic and non-probabilistic approaches have both been employed to characterize uncertainties associated with risk assessment. The probabilistic approaches include sampling-based methods (typically Monte Carlo simulation and stratified sampling) and asymptotic (approximate) reliability analysis (first- and second-order reliability methods). Non-probabilistic approaches include interval analysis, fuzzy set theory and possibility theory. However, it is generally accepted that no single method is suitable for the entire spectrum of problems encountered in uncertainty analyses for risk assessment. Each method has its own set of advantages and limitations. In this paper, the feasibility and limitations of different uncertainty analysis approaches are outlined for risk management studies of drinking water supply systems. The findings assist in the selection of suitable approaches for uncertainty analysis in risk management studies associated with DBPs and human health risk.

Cost-effectiveness analysis of quadrivalent influenza vaccine in Spain.

PubMed

García, Amos; Ortiz de Lejarazu, Raúl; Reina, Jordi; Callejo, Daniel; Cuervo, Jesús; Morano Larragueta, Raúl

2016-09-01

Influenza has a major impact on healthcare systems and society, but can be prevented using vaccination. The World Health Organization (WHO) currently recommends that influenza vaccines should include at least two virus A and one virus B lineage (trivalent vaccine; TIV). A new quadrivalent vaccine (QIV), which includes an additional B virus strain, received regulatory approval and is now recommended by several countries. The present study estimates the cost-effectiveness of replacing TIVs with QIV for risk groups and elderly population in Spain. A static, lifetime, multi-cohort Markov model with a one-year cycle time was adapted to assess the costs and health outcomes associated with a switch from TIV to QIV. The model followed a cohort vaccinated each year according to health authority recommendations, for the duration of their lives. National epidemiological data allowed the determination of whether the B strain included in TIVs matched the circulating one. Societal perspective was considered, costs and outcomes were discounted at 3% and one-way and probabilistic sensitivity analyses were performed. Compared to TIVs, QIV reduced more influenza cases and influenza-related complications and deaths during periods of B-mismatch strains in the TIV. The incremental cost-effectiveness ratio (ICER) was 8,748€/quality-adjusted life year (QALY). One-way sensitivity analysis showed mismatch with the B lineage included in the TIV was the main driver for ICER. Probabilistic sensitivity analysis shows ICER below 30,000€/QALY in 96% of simulations. Replacing TIVs with QIV in Spain could improve influenza prevention by avoiding B virus mismatch and provide a cost-effective healthcare intervention.

The cost-effectiveness of smoking cessation support delivered by mobile phone text messaging: Txt2stop.

PubMed

Guerriero, Carla; Cairns, John; Roberts, Ian; Rodgers, Anthony; Whittaker, Robyn; Free, Caroline

2013-10-01

The txt2stop trial has shown that mobile-phone-based smoking cessation support doubles biochemically validated quitting at 6 months. This study examines the cost-effectiveness of smoking cessation support delivered by mobile phone text messaging. The lifetime incremental costs and benefits of adding text-based support to current practice are estimated from a UK NHS perspective using a Markov model. The cost-effectiveness was measured in terms of cost per quitter, cost per life year gained and cost per QALY gained. As in previous studies, smokers are assumed to face a higher risk of experiencing the following five diseases: lung cancer, stroke, myocardial infarction, chronic obstructive pulmonary disease, and coronary heart disease (i.e. the main fatal or disabling, but by no means the only, adverse effects of prolonged smoking). The treatment costs and health state values associated with these diseases were identified from the literature. The analysis was based on the age and gender distribution observed in the txt2stop trial. Effectiveness and cost parameters were varied in deterministic sensitivity analyses, and a probabilistic sensitivity analysis was also performed. The cost of text-based support per 1,000 enrolled smokers is £16,120, which, given an estimated 58 additional quitters at 6 months, equates to £278 per quitter. However, when the future NHS costs saved (as a result of reduced smoking) are included, text-based support would be cost saving. It is estimated that 18 LYs are gained per 1,000 smokers (0.3 LYs per quitter) receiving text-based support, and 29 QALYs are gained (0.5 QALYs per quitter). The deterministic sensitivity analysis indicated that changes in individual model parameters did not alter the conclusion that this is a cost-effective intervention. Similarly, the probabilistic sensitivity analysis indicated a >90 % chance that the intervention will be cost saving. This study shows that under a wide variety of conditions, personalised smoking cessation advice and support by mobile phone message is both beneficial for health and cost saving to a health system.

Cost-effectiveness analysis for joint pain treatment in patients with osteoarthritis treated at the Instituto Mexicano del Seguro Social (IMSS): Comparison of nonsteroidal anti-inflammatory drugs (NSAIDs) vs. cyclooxygenase-2 selective inhibitors.

PubMed

Contreras-Hernández, Iris; Mould-Quevedo, Joaquín F; Torres-González, Rubén; Goycochea-Robles, María Victoria; Pacheco-Domínguez, Reyna Lizette; Sánchez-García, Sergio; Mejía-Aranguré, Juan Manuel; Garduño-Espinosa, Juan

2008-11-12

Osteoarthritis (OA) is one of the main causes of disability worldwide, especially in persons >55 years of age. Currently, controversy remains about the best therapeutic alternative for this disease when evaluated from a cost-effectiveness viewpoint. For Social Security Institutions in developing countries, it is very important to assess what drugs may decrease the subsequent use of medical care resources, considering their adverse events that are known to have a significant increase in medical care costs of patients with OA. Three treatment alternatives were compared: celecoxib (200 mg twice daily), non-selective NSAIDs (naproxen, 500 mg twice daily; diclofenac, 100 mg twice daily; and piroxicam, 20 mg/day) and acetaminophen, 1000 mg twice daily. The aim of this study was to identify the most cost-effective first-choice pharmacological treatment for the control of joint pain secondary to OA in patients treated at the Instituto Mexicano del Seguro Social (IMSS). A cost-effectiveness assessment was carried out. A systematic review of the literature was performed to obtain transition probabilities. In order to evaluate analysis robustness, one-way and probabilistic sensitivity analyses were conducted. Estimations were done for a 6-month period. Treatment demonstrating the best cost-effectiveness results [lowest cost-effectiveness ratio $17.5 pesos/patient ($1.75 USD)] was celecoxib. According to the one-way sensitivity analysis, celecoxib would need to markedly decrease its effectiveness in order for it to not be the optimal treatment option. In the probabilistic analysis, both in the construction of the acceptability curves and in the estimation of net economic benefits, the most cost-effective option was celecoxib. From a Mexican institutional perspective and probably in other Social Security Institutions in similar developing countries, the most cost-effective option for treatment of knee and/or hip OA would be celecoxib.

Cost-effectiveness analysis for joint pain treatment in patients with osteoarthritis treated at the Instituto Mexicano del Seguro Social (IMSS): Comparison of nonsteroidal anti-inflammatory drugs (NSAIDs) vs. cyclooxygenase-2 selective inhibitors

PubMed Central

Contreras-Hernández, Iris; Mould-Quevedo, Joaquín F; Torres-González, Rubén; Goycochea-Robles, María Victoria; Pacheco-Domínguez, Reyna Lizette; Sánchez-García, Sergio; Mejía-Aranguré, Juan Manuel; Garduño-Espinosa, Juan

2008-01-01

Background Osteoarthritis (OA) is one of the main causes of disability worldwide, especially in persons >55 years of age. Currently, controversy remains about the best therapeutic alternative for this disease when evaluated from a cost-effectiveness viewpoint. For Social Security Institutions in developing countries, it is very important to assess what drugs may decrease the subsequent use of medical care resources, considering their adverse events that are known to have a significant increase in medical care costs of patients with OA. Three treatment alternatives were compared: celecoxib (200 mg twice daily), non-selective NSAIDs (naproxen, 500 mg twice daily; diclofenac, 100 mg twice daily; and piroxicam, 20 mg/day) and acetaminophen, 1000 mg twice daily. The aim of this study was to identify the most cost-effective first-choice pharmacological treatment for the control of joint pain secondary to OA in patients treated at the Instituto Mexicano del Seguro Social (IMSS). Methods A cost-effectiveness assessment was carried out. A systematic review of the literature was performed to obtain transition probabilities. In order to evaluate analysis robustness, one-way and probabilistic sensitivity analyses were conducted. Estimations were done for a 6-month period. Results Treatment demonstrating the best cost-effectiveness results [lowest cost-effectiveness ratio $17.5 pesos/patient ($1.75 USD)] was celecoxib. According to the one-way sensitivity analysis, celecoxib would need to markedly decrease its effectiveness in order for it to not be the optimal treatment option. In the probabilistic analysis, both in the construction of the acceptability curves and in the estimation of net economic benefits, the most cost-effective option was celecoxib. Conclusion From a Mexican institutional perspective and probably in other Social Security Institutions in similar developing countries, the most cost-effective option for treatment of knee and/or hip OA would be celecoxib. PMID:19014495

Cost-effectiveness of early compared to late inhaled nitric oxide therapy in near-term infants.

PubMed

Armstrong, Edward P; Dhanda, Rahul

2010-12-01

The purpose of this study was to determine the cost-effectiveness of early versus late inhaled nitric oxide (INO) therapy in neonates with hypoxic respiratory failure initially managed on conventional mechanical ventilation. A decision analytic model was created to compare the use of early INO compared to delayed INO for neonates receiving mechanical ventilation due to hypoxic respiratory failure. The perspective of the model was that of a hospital. Patients who did not respond to either early or delayed INO were assumed to have been treated with extracorporeal membrane oxygenation (ECMO). The effectiveness measure was defined as a neonate discharged alive without requiring ECMO therapy. A Monte Carlo simulation of 10,000 cases was conducted using first and second order probabilistic analysis. Direct medical costs that differed between early versus delayed INO treatment were estimated until time to hospital discharge. The proportion of successfully treated patients and costs were determined from the probabilistic sensitivity analysis. The mean (± SD) effectiveness rate for early INO was 0.75 (± 0.08) and 0.61 (± 0.09) for delayed INO. The mean hospital cost for early INO was $21,462 (± $2695) and $27,226 (± $3532) for delayed INO. In 87% of scenarios, early INO dominated delayed INO by being both more effective and less costly. The acceptability curve between products demonstrated that early INO had over a 90% probability of being the most cost-effective treatment across a wide range of willingness to pay values. This analysis indicated that early INO therapy was cost-effective in neonates with hypoxic respiratory failure requiring mechanical ventilation compared to delayed INO by reducing the probability of developing severe hypoxic respiratory failure. There was a 90% or higher probability that early INO was more cost-effective than delayed INO across a wide range of willingness to pay values in this analysis.

Economic evaluation of home-based telebehavioural health care compared to in-person treatment delivery for depression.

PubMed

Bounthavong, Mark; Pruitt, Larry D; Smolenski, Derek J; Gahm, Gregory A; Bansal, Aasthaa; Hansen, Ryan N

2018-02-01

Introduction Home-based telebehavioural healthcare improves access to mental health care for patients restricted by travel burden. However, there is limited evidence assessing the economic value of home-based telebehavioural health care compared to in-person care. We sought to compare the economic impact of home-based telebehavioural health care and in-person care for depression among current and former US service members. Methods We performed trial-based cost-minimisation and cost-utility analyses to assess the economic impact of home-based telebehavioural health care versus in-person behavioural care for depression. Our analyses focused on the payer perspective (Department of Defense and Department of Veterans Affairs) at three months. We also performed a scenario analysis where all patients possessed video-conferencing technology that was approved by these agencies. The cost-utility analysis evaluated the impact of different depression categories on the incremental cost-effectiveness ratio. One-way and probabilistic sensitivity analyses were performed to test the robustness of the model assumptions. Results In the base case analysis the total direct cost of home-based telebehavioural health care was higher than in-person care (US$71,974 versus US$20,322). Assuming that patients possessed government-approved video-conferencing technology, home-based telebehavioural health care was less costly compared to in-person care (US$19,177 versus US$20,322). In one-way sensitivity analyses, the proportion of patients possessing personal computers was a major driver of direct costs. In the cost-utility analysis, home-based telebehavioural health care was dominant when patients possessed video-conferencing technology. Results from probabilistic sensitivity analyses did not differ substantially from base case results. Discussion Home-based telebehavioural health care is dependent on the cost of supplying video-conferencing technology to patients but offers the opportunity to increase access to care. Health-care policies centred on implementation of home-based telebehavioural health care should ensure that these technologies are able to be successfully deployed on patients' existing technology.

The cost effectiveness of radon mitigation in existing German dwellings--a decision theoretic analysis.

PubMed

Haucke, Florian

2010-11-01

Radon is a naturally occurring inert radioactive gas found in soils and rocks that can accumulate in dwellings, and is associated with an increased risk of lung cancer. This study aims to analyze the cost effectiveness of different intervention strategies to reduce radon concentrations in existing German dwellings. The cost effectiveness analysis (CEA) was conducted as a scenario analysis, where each scenario represents a specific regulatory regime. A decision theoretic model was developed, which reflects accepted recommendations for radon screening and mitigation and uses most up-to-date data on radon distribution and relative risks. The model was programmed to account for compliance with respect to the single steps of radon intervention, as well as data on the sensitivity/specificity of radon tests. A societal perspective was adopted to calculate costs and effects. All scenarios were calculated for different action levels. Cost effectiveness was measured in costs per averted case of lung cancer, costs per life year gained and costs per quality adjusted life year (QALY) gained. Univariate and multivariate deterministic and probabilistic sensitivity analyses (SA) were performed. Probabilistic sensitivity analyses were based on Monte Carlo simulations with 5000 model runs. The results show that legal regulations with mandatory screening and mitigation for indoor radon levels >100 Bq/m(3) are most cost effective. Incremental cost effectiveness compared to the no mitigation base case is 25,181 euro (95% CI: 7371 euro-90,593 euro) per QALY gained. Other intervention strategies focussing primarily on the personal responsibility for screening and/or mitigative actions show considerably worse cost effectiveness ratios. However, targeting radon intervention to radon-prone areas is significantly more cost effective. Most of the uncertainty that surrounds the results can be ascribed to the relative risk of radon exposure. It can be concluded that in the light of international experience a legal regulation requiring radon screening and, if necessary, mitigation is justifiable under the terms of CEA. Copyright 2010 Elsevier Ltd. All rights reserved.

Cost-Effectiveness Analysis of Preoperative Versus Postoperative Radiation Therapy in Extremity Soft Tissue Sarcoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, Xuanlu M.; Louie, Alexander V.; Ashman, Jonathan

Purpose: Surgery combined with radiation therapy (RT) is the cornerstone of multidisciplinary management of extremity soft tissue sarcoma (STS). Although RT can be given in either the preoperative or the postoperative setting with similar local recurrence and survival outcomes, the side effect profiles, costs, and long-term functional outcomes are different. The aim of this study was to use decision analysis to determine optimal sequencing of RT with surgery in patients with extremity STS. Methods and Materials: A cost-effectiveness analysis was conducted using a state transition Markov model, with quality-adjusted life years (QALYs) as the primary outcome. A time horizon ofmore » 5 years, a cycle length of 3 months, and a willingness-to-pay threshold of $50,000/QALY was used. One-way deterministic sensitivity analyses were performed to determine the thresholds at which each strategy would be preferred. The robustness of the model was assessed by probabilistic sensitivity analysis. Results: Preoperative RT is a more cost-effective strategy ($26,633/3.00 QALYs) than postoperative RT ($28,028/2.86 QALYs) in our base case scenario. Preoperative RT is the superior strategy with either 3-dimensional conformal RT or intensity-modulated RT. One-way sensitivity analyses identified the relative risk of chronic adverse events as having the greatest influence on the preferred timing of RT. The likelihood of preoperative RT being the preferred strategy was 82% on probabilistic sensitivity analysis. Conclusions: Preoperative RT is more cost effective than postoperative RT in the management of resectable extremity STS, primarily because of the higher incidence of chronic adverse events with RT in the postoperative setting.« less

Potential cost-effectiveness of universal access to modern contraceptives in Uganda.

PubMed

Babigumira, Joseph B; Stergachis, Andy; Veenstra, David L; Gardner, Jacqueline S; Ngonzi, Joseph; Mukasa-Kivunike, Peter; Garrison, Louis P

2012-01-01

Over two thirds of women who need contraception in Uganda lack access to modern effective methods. This study was conducted to estimate the potential cost-effectiveness of achieving universal access to modern contraceptives in Uganda by implementing a hypothetical new contraceptive program (NCP) from both societal and governmental (Ministry of Health (MoH)) perspectives. A Markov model was developed to compare the NCP to the status quo or current contraceptive program (CCP). The model followed a hypothetical cohort of 15-year old girls over a lifetime horizon. Data were obtained from the Uganda National Demographic and Health Survey and from published and unpublished sources. Costs, life expectancy, disability-adjusted life expectancy, pregnancies, fertility and incremental cost-effectiveness measured as cost per life-year (LY) gained, cost per disability-adjusted life-year (DALY) averted, cost per pregnancy averted and cost per unit of fertility reduction were calculated. Univariate and probabilistic sensitivity analyses were performed to examine the robustness of results. Mean discounted life expectancy and disability-adjusted life expectancy (DALE) were higher under the NCP vs. CCP (28.74 vs. 28.65 years and 27.38 vs. 27.01 respectively). Mean pregnancies and live births per woman were lower under the NCP (9.51 vs. 7.90 and 6.92 vs. 5.79 respectively). Mean lifetime societal costs per woman were lower for the NCP from the societal perspective ($1,949 vs. $1,987) and the MoH perspective ($636 vs. $685). In the incremental analysis, the NCP dominated the CCP, i.e. it was both less costly and more effective. The results were robust to univariate and probabilistic sensitivity analysis. Universal access to modern contraceptives in Uganda appears to be highly cost-effective. Increasing contraceptive coverage should be considered among Uganda's public health priorities.

Cost-Effectiveness of Thrombolysis within 4.5 Hours of Acute Ischemic Stroke in China

PubMed Central

Zhao, Xingquan; Liao, Xiaoling; Wang, Chunjuan; Du, Wanliang; Liu, Gaifen; Liu, Liping; Wang, Chunxue; Wang, Yilong; Wang, Yongjun

2014-01-01

Background Previous economic studies conducted in developed countries showed intravenous tissue-type plasminogen activator (tPA) is cost-effective for acute ischemic stroke. The present study aimed to determine the cost-effectiveness of tPA treatment in China, the largest developing country. Methods A combination of decision tree and Markov model was developed to determine the cost-effectiveness of tPA treatment versus non-tPA treatment within 4.5 hours after stroke onset. Outcomes and costs data were derived from the database of Thrombolysis Implementation and Monitor of acute ischemic Stroke in China (TIMS-China) study. Efficacy data were derived from a pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials. Costs and quality-adjusted life-years (QALYs) were compared in both short term (2 years) and long term (30 years). One-way and probabilistic sensitivity analyses were performed to test the robustness of the results. Results Comparing to non-tPA treatment, tPA treatment within 4.5 hours led to a short-term gain of 0.101 QALYs at an additional cost of CNY 9,520 (US$ 1,460), yielding an incremental cost-effectiveness ratio (ICER) of CNY 94,300 (US$ 14,500) per QALY gained in 2 years; and to a long-term gain of 0.422 QALYs at an additional cost of CNY 6,530 (US$ 1,000), yielding an ICER of CNY 15,500 (US$ 2,380) per QALY gained in 30 years. Probabilistic sensitivity analysis showed that tPA treatment is cost-effective in 98.7% of the simulations at a willingness-to-pay threshold of CNY 105,000 (US$ 16,200) per QALY. Conclusions Intravenous tPA treatment within 4.5 hours is highly cost-effective for acute ischemic strokes in China. PMID:25329637

Cost-effectiveness analysis of neurocognitive-sparing treatments for brain metastases.

PubMed

Savitz, Samuel T; Chen, Ronald C; Sher, David J

2015-12-01

Decisions regarding how to treat patients who have 1 to 3 brain metastases require important tradeoffs between controlling recurrences, side effects, and costs. In this analysis, the authors compared novel treatments versus usual care to determine the incremental cost-effectiveness ratio from a payer's (Medicare) perspective. Cost-effectiveness was evaluated using a microsimulation of a Markov model for 60 one-month cycles. The model used 4 simulated cohorts of patients aged 65 years with 1 to 3 brain metastases. The 4 cohorts had a median survival of 3, 6, 12, and 24 months to test the sensitivity of the model to different prognoses. The treatment alternatives evaluated included stereotactic radiosurgery (SRS) with 3 variants of salvage after recurrence (whole-brain radiotherapy [WBRT], hippocampal avoidance WBRT [HA-WBRT], SRS plus WBRT, and SRS plus HA-WBRT). The findings were tested for robustness using probabilistic and deterministic sensitivity analyses. Traditional radiation therapies remained cost-effective for patients in the 3-month and 6-month cohorts. In the cohorts with longer median survival, HA-WBRT and SRS plus HA-WBRT became cost-effective relative to traditional treatments. When the treatments that involved HA-WBRT were excluded, either SRS alone or SRS plus WBRT was cost-effective relative to WBRT alone. The deterministic and probabilistic sensitivity analyses confirmed the robustness of these results. HA-WBRT and SRS plus HA-WBRT were cost-effective for 2 of the 4 cohorts, demonstrating the value of controlling late brain toxicity with this novel therapy. Cost-effectiveness depended on patient life expectancy. SRS was cost-effective in the cohorts with short prognoses (3 and 6 months), whereas HA-WBRT and SRS plus HA-WBRT were cost-effective in the cohorts with longer prognoses (12 and 24 months). © 2015 American Cancer Society.

Strategies to Screen for Diabetic Retinopathy in Chinese Patients with Newly Diagnosed Type 2 Diabetes: A Cost-Effectiveness Analysis.

PubMed

Wu, Bin; Li, Jin; Wu, Haixiang

2015-11-01

To investigate the cost-effectiveness of different screening intervals for diabetic retinopathy (DR) in Chinese patients with newly diagnosed type 2 diabetes mellitus (T2DM). Chinese healthcare system.Chinese general clinical setting. A cost-effectiveness model was developed to simulate the disease course of Chinese population with newly diagnosed with diabetes. Different DR screening programs were modeled to project economic outcomes. To develop the economic model, we calibrated the progression rates of DR that fit Chinese epidemiologic data derived from the published literature. Costs were estimated from the perspective of the Chinese healthcare system, and the analysis was run over a lifetime horizon. One-way and probabilistic sensitivity analyses were performed. Total costs, vision outcomes, costs per quality-adjusted life year (QALY), the incremental cost-effectiveness ratio (ICER) of screening strategies compared to no screening. DR screening is effective in Chinese patients with newly diagnosed T2DM, and screen strategies with ≥4-year intervals were cost-effective (ICER <$7,485 per QALY) compared to no screening. Screening every 4 years produced the greatest increase in QALYs (11.066) among the cost-effective strategies. The screening intervals could be varied dramatically by age at T2DM diagnosis. Probabilistic sensitivity analyses demonstrated the consistency and robustness of the cost-effectiveness of the 4-year interval screening strategy. The findings suggest that a 4-year interval screening strategy is likely to be more cost-effective than screening every 1 to 3 years in comparison with no screening in the Chinese setting. The screening intervals might be tailored according to the age at T2DM diagnosis.

Cost-effectiveness of thrombolysis within 4.5 hours of acute ischemic stroke in China.

PubMed

Pan, Yuesong; Chen, Qidong; Zhao, Xingquan; Liao, Xiaoling; Wang, Chunjuan; Du, Wanliang; Liu, Gaifen; Liu, Liping; Wang, Chunxue; Wang, Yilong; Wang, Yongjun

2014-01-01

Previous economic studies conducted in developed countries showed intravenous tissue-type plasminogen activator (tPA) is cost-effective for acute ischemic stroke. The present study aimed to determine the cost-effectiveness of tPA treatment in China, the largest developing country. A combination of decision tree and Markov model was developed to determine the cost-effectiveness of tPA treatment versus non-tPA treatment within 4.5 hours after stroke onset. Outcomes and costs data were derived from the database of Thrombolysis Implementation and Monitor of acute ischemic Stroke in China (TIMS-China) study. Efficacy data were derived from a pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials. Costs and quality-adjusted life-years (QALYs) were compared in both short term (2 years) and long term (30 years). One-way and probabilistic sensitivity analyses were performed to test the robustness of the results. Comparing to non-tPA treatment, tPA treatment within 4.5 hours led to a short-term gain of 0.101 QALYs at an additional cost of CNY 9,520 (US$ 1,460), yielding an incremental cost-effectiveness ratio (ICER) of CNY 94,300 (US$ 14,500) per QALY gained in 2 years; and to a long-term gain of 0.422 QALYs at an additional cost of CNY 6,530 (US$ 1,000), yielding an ICER of CNY 15,500 (US$ 2,380) per QALY gained in 30 years. Probabilistic sensitivity analysis showed that tPA treatment is cost-effective in 98.7% of the simulations at a willingness-to-pay threshold of CNY 105,000 (US$ 16,200) per QALY. Intravenous tPA treatment within 4.5 hours is highly cost-effective for acute ischemic strokes in China.

Cost-Utility Analysis: Sartorius Flap versus Negative Pressure Therapy for Infected Vascular Groin Graft Managment

PubMed Central

Macarios, David; Griffin, Leah; Kosowski, Tomasz; Pyfer, Bryan J.; Offodile, Anaeze C.; Driscoll, Daniel; Maddali, Sirish; Attwood, John

2015-01-01

Background: Sartorius flap coverage and adjunctive negative pressure wound therapy (NPWT) have been described in managing infected vascular groin grafts with varying cost and clinical success. We performed a cost–utility analysis comparing sartorius flap with NPWT in managing an infected vascular groin graft. Methods: A literature review compiling outcomes for sartorius flap and NPWT interventions was conducted from peer-reviewed journals in MEDLINE (PubMed) and EMBASE. Utility scores were derived from expert opinion and used to estimate quality-adjusted life years (QALYs). Medicare current procedure terminology and diagnosis-related groups codes were used to assess the costs for successful graft salvage with the associated complications. Incremental cost-effectiveness was assessed at $50,000/QALY, and both univariate and probabilistic sensitivity analyses were conducted to assess robustness of the conclusions. Results: Thirty-two studies were used pooling 384 patients (234 sartorius flaps and 150 NPWT). NPWT had better clinical outcomes (86.7% success rate, 0.9% minor complication rate, and 13.3% major complication rate) than sartorius flap (81.6% success rate, 8.0% minor complication rate, and 18.4% major complication rate). NPWT was less costly ($12,366 versus $23,516) and slightly more effective (12.06 QALY versus 12.05 QALY) compared with sartorius flap. Sensitivity analyses confirmed the robustness of the base case findings; NPWT was either cost-effective at $50,000/QALY or dominated sartorius flap in 81.6% of all probabilistic sensitivity analyses. Conclusion: In our cost–utility analysis, use of adjunctive NPWT, along with debridement and antibiotic treatment, for managing infected vascular groin graft wounds was found to be a more cost-effective option when compared with sartorius flaps. PMID:26893991

Cost-effectiveness of supervised exercise therapy compared with endovascular revascularization for intermittent claudication.

PubMed

van den Houten, M M L; Lauret, G J; Fakhry, F; Fokkenrood, H J P; van Asselt, A D I; Hunink, M G M; Teijink, J A W

2016-11-01

Current guidelines recommend supervised exercise therapy (SET) as the preferred initial treatment for patients with intermittent claudication. The availability of SET programmes is, however, limited and such programmes are often not reimbursed. Evidence for the long-term cost-effectiveness of SET compared with endovascular revascularization (ER) as primary treatment for intermittent claudication might aid widespread adoption in clinical practice. A Markov model was constructed to determine the incremental costs, incremental quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio of SET versus ER for a hypothetical cohort of patients with newly diagnosed intermittent claudication, from the Dutch healthcare payer's perspective. In the event of primary treatment failure, possible secondary interventions were repeat ER, open revascularization or major amputation. Data sources for model parameters included original data from two RCTs, as well as evidence from the medical literature. The robustness of the results was tested with probabilistic and one-way sensitivity analysis. Considering a 5-year time horizon, probabilistic sensitivity analysis revealed that SET was associated with cost savings compared with ER (-€6412, 95 per cent credibility interval (CrI) -€11 874 to -€1939). The mean difference in effectiveness was -0·07 (95 per cent CrI -0·27 to 0·16) QALYs. ER was associated with an additional €91 600 per QALY gained compared with SET. One-way sensitivity analysis indicated more favourable cost-effectiveness for ER in subsets of patients with low quality-of-life scores at baseline. SET is a more cost-effective primary treatment for intermittent claudication than ER. These results support implementation of supervised exercise programmes in clinical practice. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

Cost-effectiveness of pressure-relieving devices for the prevention and treatment of pressure ulcers.

PubMed

Fleurence, Rachael L

2005-01-01

The cost-effectiveness of alternating pressure-relieving devices, mattress replacements, and mattress overlays compared with a standard hospital (high-specification foam mattress) for the prevention and treatment of pressure ulcers in hospital patients in the United Kingdom was investigated. A decision-analytic model was constructed to evaluate different strategies to prevent or treat pressure ulcers. Three scenarios were evaluated: the prevention of pressure ulcers, the treatment of superficial ulcers, and the treatment of severe ulcers. Epidemiological and effectiveness data were obtained from the clinical literature. Expert opinion using a rating scale technique was used to obtain quality of life data. Costs of the devices were obtained from manufacturers, whereas costs of treatment were obtained from the literature. Uncertainty was explored through probabilistic sensitivity analysis. Using 30,000 pounds sterling/QALY (quality-adjusted life year) as the decision-maker's cut off point (the current UK standard), in scenario 1 (prevention), the cost-effective strategy was the mattress overlay at 1, 4, and 12 weeks. In scenarios 2 and 3, the cost-effective strategy was the mattress replacement at 1, 4, and 12 weeks. Standard care was a dominated intervention in all scenarios for values of the decision-maker's ceiling ratio ranging from 5,000 pounds sterling to 100,000 pounds sterling/QALY. However, the probabilistic sensitivity analysis results reflected the high uncertainty surrounding the choice of devices. Current information suggests that alternating pressure mattress overlays may be cost-effective for the prevention of pressure ulcers, whereas alternating pressure mattress replacements appears to be cost-effective for the treatment of superficial and severe pressure ulcers.

Cost-effectiveness of bazedoxifene versus raloxifene in the treatment of postmenopausal women in Spain

PubMed Central

Darbà, Josep; Pérez-Álvarez, Nuria; Kaskens, Lisette; Holgado-Pérez, Susana; Racketa, Jill; Rejas, Javier

2013-01-01

Background The purpose of this study was to assess the cost-effectiveness of bazedoxifene and raloxifene for prevention of vertebral and nonvertebral fractures among postmenopausal Spanish women aged 55–82 years with established osteoporosis and a high fracture risk. Methods A Markov model was developed to represent the transition of a cohort of postmenopausal osteoporotic women through different health states, ie, patients free of fractures, patients with vertebral or nonvertebral fractures, and patients recovered from a fracture. Efficacy data for bazedoxifene were obtained from the Osteoporosis Study. The perspective of the Spanish National Health Service was chosen with a time horizon of 27 years. Costs were reported in 2010 Euros. Deterministic results were presented as expected cost per quality-adjusted life-year (QALY), and probabilistic results were represented in cost-effectiveness planes. Results In deterministic analysis, the expected cost per patient was higher in the raloxifene cohort (€13,881) than in the bazedoxifene cohort (€13,436). QALYs gained were slightly higher in the bazedoxifene cohort (14.56 versus 14.54). Results from probabilistic sensitivity analysis showed that bazedoxifene has a slightly higher probability of being cost-effective for all threshold values independent of the maximum that the National Health Service is willing to pay per additional QALY. Conclusion Bazedoxifene was shown to be a cost-effective treatment option for the prevention of fractures in Spanish women with postmenopausal osteoporosis and a high fracture risk. When comparing bazedoxifene with raloxifene, it may be concluded that the former is the dominant strategy. PMID:23882153

Design for Reliability and Safety Approach for the NASA New Launch Vehicle

NASA Technical Reports Server (NTRS)

Safie, Fayssal, M.; Weldon, Danny M.

2007-01-01

The United States National Aeronautics and Space Administration (NASA) is in the midst of a space exploration program intended for sending crew and cargo to the international Space Station (ISS), to the moon, and beyond. This program is called Constellation. As part of the Constellation program, NASA is developing new launch vehicles aimed at significantly increase safety and reliability, reduce the cost of accessing space, and provide a growth path for manned space exploration. Achieving these goals requires a rigorous process that addresses reliability, safety, and cost upfront and throughout all the phases of the life cycle of the program. This paper discusses the "Design for Reliability and Safety" approach for the NASA new crew launch vehicle called ARES I. The ARES I is being developed by NASA Marshall Space Flight Center (MSFC) in support of the Constellation program. The ARES I consists of three major Elements: A solid First Stage (FS), an Upper Stage (US), and liquid Upper Stage Engine (USE). Stacked on top of the ARES I is the Crew exploration vehicle (CEV). The CEV consists of a Launch Abort System (LAS), Crew Module (CM), Service Module (SM), and a Spacecraft Adapter (SA). The CEV development is being led by NASA Johnson Space Center (JSC). Designing for high reliability and safety require a good integrated working environment and a sound technical design approach. The "Design for Reliability and Safety" approach addressed in this paper discusses both the environment and the technical process put in place to support the ARES I design. To address the integrated working environment, the ARES I project office has established a risk based design group called "Operability Design and Analysis" (OD&A) group. This group is an integrated group intended to bring together the engineering, design, and safety organizations together to optimize the system design for safety, reliability, and cost. On the technical side, the ARES I project has, through the OD&A environment, implemented a probabilistic approach to analyze and evaluate design uncertainties and understand their impact on safety, reliability, and cost. This paper focuses on the use of the various probabilistic approaches that have been pursued by the ARES I project. Specifically, the paper discusses an integrated functional probabilistic analysis approach that addresses upffont some key areas to support the ARES I Design Analysis Cycle (DAC) pre Preliminary Design (PD) Phase. This functional approach is a probabilistic physics based approach that combines failure probabilities with system dynamics and engineering failure impact models to identify key system risk drivers and potential system design requirements. The paper also discusses other probabilistic risk assessment approaches planned by the ARES I project to support the PD phase and beyond.

Cost-effectiveness analysis of risk-reduction measures to reach water safety targets.

PubMed

Lindhe, Andreas; Rosén, Lars; Norberg, Tommy; Bergstedt, Olof; Pettersson, Thomas J R

2011-01-01

Identifying the most suitable risk-reduction measures in drinking water systems requires a thorough analysis of possible alternatives. In addition to the effects on the risk level, also the economic aspects of the risk-reduction alternatives are commonly considered important. Drinking water supplies are complex systems and to avoid sub-optimisation of risk-reduction measures, the entire system from source to tap needs to be considered. There is a lack of methods for quantification of water supply risk reduction in an economic context for entire drinking water systems. The aim of this paper is to present a novel approach for risk assessment in combination with economic analysis to evaluate risk-reduction measures based on a source-to-tap approach. The approach combines a probabilistic and dynamic fault tree method with cost-effectiveness analysis (CEA). The developed approach comprises the following main parts: (1) quantification of risk reduction of alternatives using a probabilistic fault tree model of the entire system; (2) combination of the modelling results with CEA; and (3) evaluation of the alternatives with respect to the risk reduction, the probability of not reaching water safety targets and the cost-effectiveness. The fault tree method and CEA enable comparison of risk-reduction measures in the same quantitative unit and consider costs and uncertainties. The approach provides a structured and thorough analysis of risk-reduction measures that facilitates transparency and long-term planning of drinking water systems in order to avoid sub-optimisation of available resources for risk reduction. Copyright © 2010 Elsevier Ltd. All rights reserved.

Cost-Effectiveness Analysis of Bendamustine Plus Rituximab as a First-Line Treatment for Patients with Follicular Lymphoma in Spain.

PubMed

Sabater, Eliazar; López-Guillermo, Armando; Rueda, Antonio; Salar, Antonio; Oyagüez, Itziar; Collar, Juan Manuel

2016-08-01

Follicular lymphoma (FL) is the second most common type of lymphoid cancer in Western Europe. The aim of this study was to evaluate the cost utility of rituximab-bendamustine treatment compared with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) treatment as a first-line therapy for patients with advanced FL in Spain. A Markov model was developed to estimate the cost effectiveness of rituximab-bendamustine compared with R-CHOP as first-line treatment for patients with advanced FL in the Spanish National Health System (NHS). Transitions between health states (progression-free, including induction and maintenance; first relapse; second relapse; and death) were allowed for the patient cohort in 4-week-long cycles. Clinical data for the extrapolation of progression-free survival curves were obtained from randomized trials. Mortality rates and utilities were obtained from the literature. Outcomes were measured as quality-adjusted life-years (QALYs). The total costs (€, 2013) included drug costs (ex-factory prices with mandatory deductions), disease management costs and adverse event-associated costs. Costs and outcomes were discounted at a 3 % annual rate. Probabilistic sensitivity analysis was performed using 10,000 Monte Carlo simulations to assess the model robustness. Treatment and administration costs during the induction phase were higher for rituximab-bendamustine (€17,671) than for R-CHOP (€11,850). At the end of the 25-year period, the rituximab-bendamustine first-line strategy had a total cost of €68,357 compared with €69,528 for R-CHOP. Health benefits were higher for rituximab-bendamustine treatment (10.31 QALYs) than for R-CHOP treatment (9.82 QALYs). In the probabilistic analysis, rituximab-bendamustine was the dominant strategy over treatment with R-CHOP in 53.4 % of the simulations. First-line therapy with rituximab-bendamustine in FL patients was the dominant strategy over treatment with R-CHOP; it showed cost savings and higher health benefits for the Spanish NHS.

Probabilistic Methodology for Estimation of Number and Economic Loss (Cost) of Future Landslides in the San Francisco Bay Region, California

USGS Publications Warehouse

Crovelli, Robert A.; Coe, Jeffrey A.

2008-01-01

The Probabilistic Landslide Assessment Cost Estimation System (PLACES) presented in this report estimates the number and economic loss (cost) of landslides during a specified future time in individual areas, and then calculates the sum of those estimates. The analytic probabilistic methodology is based upon conditional probability theory and laws of expectation and variance. The probabilistic methodology is expressed in the form of a Microsoft Excel computer spreadsheet program. Using historical records, the PLACES spreadsheet is used to estimate the number of future damaging landslides and total damage, as economic loss, from future landslides caused by rainstorms in 10 counties of the San Francisco Bay region in California. Estimates are made for any future 5-year period of time. The estimated total number of future damaging landslides for the entire 10-county region during any future 5-year period of time is about 330. Santa Cruz County has the highest estimated number of damaging landslides (about 90), whereas Napa, San Francisco, and Solano Counties have the lowest estimated number of damaging landslides (5?6 each). Estimated direct costs from future damaging landslides for the entire 10-county region for any future 5-year period are about US $76 million (year 2000 dollars). San Mateo County has the highest estimated costs ($16.62 million), and Solano County has the lowest estimated costs (about $0.90 million). Estimated direct costs are also subdivided into public and private costs.

The potential cost-effectiveness of vaccination against herpes zoster and post-herpetic neuralgia.

PubMed

Brisson, Marc; Pellissier, James M; Camden, Stéphanie; Quach, Caroline; De Wals, Philippe

2008-01-01

A clinical trial has shown that a live-attenuated varicella-zoster virus vaccine is effective against herpes zoster (HZ) and post-herpetic neuralgia (PHN). The aim of this study was to examine the cost-effectiveness of vaccination against HZ and PHN in Canada. A cohort model was developed to estimate the burden of HZ and the cost-effectiveness of HZ vaccination, using Canadian population-based data. Different ages at vaccination were examined and probabilistic sensitivity analysis was performed. The economic evaluation was conducted from the ministry of health perspective and 5% discounting was used for costs and benefits. In Canada (population = 30 million), we estimate that each year there are 130,000 new cases of HZ, 17,000 cases of PHN and 20 deaths. Most of the pain and suffering is borne by adults over the age of 60 years and is due to PHN. Vaccinating 65-year-olds (HZ efficacy = 63%, PHN efficacy = 67%, no waning, cost/course = $150) is estimated to cost $33,000 per QALY-gained (90% CrI: 19,000-63,000). Assuming the cost per course of HZ vaccination is $150, probabilistic sensitivity analysis suggest that vaccinating between 65 and 75 years of age will likely yield cost-effectiveness ratios below $40,000 per Quality-Adjusted Life-Year (QALY) gained, while vaccinating adults older than 75 years will yield ratios less than $70,000 per QALY-gained. These results are most sensitive to the duration of vaccine protection and the cost of vaccination. In conclusion, results suggest that vaccinating adults between the ages of 65 and 75 years is likely to be cost-effective and thus to be a judicious use of scarce health care resources.

Characterizing the International Migration Barriers with a Probabilistic Multilateral Migration Model

PubMed Central

Li, Xiaomeng; Xu, Hongzhong; Chen, Jiawei; Chen, Qinghua; Zhang, Jiang; Di, Zengru

2016-01-01

Human migration is responsible for forming modern civilization and has had an important influence on the development of various countries. There are many issues worth researching, and “the reason to move” is the most basic one. The concept of migration cost in the classical self-selection theory, which was introduced by Roy and Borjas, is useful. However, migration cost cannot address global migration because of the limitations of deterministic and bilateral choice. Following the idea of migration cost, this paper developed a new probabilistic multilateral migration model by introducing the Boltzmann factor from statistical physics. After characterizing the underlying mechanism or driving force of human mobility, we reveal some interesting facts that have provided a deeper understanding of international migration, such as the negative correlation between migration costs for emigrants and immigrants and a global classification with clear regional and economic characteristics, based on clustering of migration cost vectors. In addition, we deconstruct the migration barriers using regression analysis and find that the influencing factors are complicated but can be partly (12.5%) described by several macro indexes, such as the GDP growth of the destination country, the GNI per capita and the HDI of both the source and destination countries. PMID:27597319

Characterizing the International Migration Barriers with a Probabilistic Multilateral Migration Model

NASA Astrophysics Data System (ADS)

Li, Xiaomeng; Xu, Hongzhong; Chen, Jiawei; Chen, Qinghua; Zhang, Jiang; di, Zengru

2016-09-01

Human migration is responsible for forming modern civilization and has had an important influence on the development of various countries. There are many issues worth researching, and “the reason to move” is the most basic one. The concept of migration cost in the classical self-selection theory, which was introduced by Roy and Borjas, is useful. However, migration cost cannot address global migration because of the limitations of deterministic and bilateral choice. Following the idea of migration cost, this paper developed a new probabilistic multilateral migration model by introducing the Boltzmann factor from statistical physics. After characterizing the underlying mechanism or driving force of human mobility, we reveal some interesting facts that have provided a deeper understanding of international migration, such as the negative correlation between migration costs for emigrants and immigrants and a global classification with clear regional and economic characteristics, based on clustering of migration cost vectors. In addition, we deconstruct the migration barriers using regression analysis and find that the influencing factors are complicated but can be partly (12.5%) described by several macro indexes, such as the GDP growth of the destination country, the GNI per capita and the HDI of both the source and destination countries.

Cost-consequence analysis of different active flowable hemostatic matrices in cardiac surgical procedures.

PubMed

Makhija, D; Rock, M; Xiong, Y; Epstein, J D; Arnold, M R; Lattouf, O M; Calcaterra, D

2017-06-01

A recent retrospective comparative effectiveness study found that use of the FLOSEAL Hemostatic Matrix in cardiac surgery was associated with significantly lower risks of complications, blood transfusions, surgical revisions, and shorter length of surgery than use of SURGIFLO Hemostatic Matrix. These outcome improvements in cardiac surgery procedures may translate to economic savings for hospitals and payers. The objective of this study was to estimate the cost-consequence of two flowable hemostatic matrices (FLOSEAL or SURGIFLO) in cardiac surgeries for US hospitals. A cost-consequence model was constructed using clinical outcomes from a previously published retrospective comparative effectiveness study of FLOSEAL vs SURGIFLO in adult cardiac surgeries. The model accounted for the reported differences between these products in length of surgery, rates of major and minor complications, surgical revisions, and blood product transfusions. Costs were derived from Healthcare Cost and Utilization Project's National Inpatient Sample (NIS) 2012 database and converted to 2015 US dollars. Savings were modeled for a hospital performing 245 cardiac surgeries annually, as identified as the average for hospitals in the NIS dataset. One-way sensitivity analysis and probabilistic sensitivity analysis were performed to test model robustness. The results suggest that if FLOSEAL is utilized in a hospital that performs 245 mixed cardiac surgery procedures annually, 11 major complications, 31 minor complications, nine surgical revisions, 79 blood product transfusions, and 260.3 h of cumulative operating time could be avoided. These improved outcomes correspond to a net annualized saving of $1,532,896. Cost savings remained consistent between $1.3m and $1.8m and between $911k and $2.4m, even after accounting for the uncertainty around clinical and cost inputs, in a one-way and probabilistic sensitivity analysis, respectively. Outcome differences associated with FLOSEAL vs SURGIFLO that were previously reported in a comparative effectiveness study may result in substantial cost savings for US hospitals.

Cost-effectiveness of different strategies to prevent breast and ovarian cancer in German women with a BRCA 1 or 2 mutation.

PubMed

Müller, Dirk; Danner, Marion; Rhiem, Kerstin; Stollenwerk, Björn; Engel, Christoph; Rasche, Linda; Borsi, Lisa; Schmutzler, Rita; Stock, Stephanie

2018-04-01

Women with a BRCA1 or BRCA2 mutation are at increased risk of developing breast and/or ovarian cancer. This economic modeling study evaluated different preventive interventions for 30-year-old women with a confirmed BRCA (1 or 2) mutation. A Markov model was developed to estimate the costs and benefits [i.e., quality-adjusted life years (QALYs), and life years gained (LYG)] associated with prophylactic bilateral mastectomy (BM), prophylactic bilateral salpingo-oophorectomy (BSO), BM plus BSO, BM plus BSO at age 40, and intensified surveillance. Relevant input data was obtained from a large German database including 5902 women with BRCA 1 or 2, and from the literature. The analysis was performed from the German Statutory Health Insurance (SHI) perspective. In order to assess the robustness of the results, deterministic and probabilistic sensitivity analyses were performed. With costs of €29,434 and a gain in QALYs of 17.7 (LYG 19.9), BM plus BSO at age 30 was less expensive and more effective than the other strategies, followed by BM plus BSO at age 40. Women who were offered the surveillance strategy had the highest costs at the lowest gain in QALYs/LYS. In the probabilistic sensitivity analysis, the probability of cost-saving was 57% for BM plus BSO. At a WTP of 10,000 € per QALY, the probability of the intervention being cost-effective was 80%. From the SHI perspective, undergoing BM plus immediate BSO should be recommended to BRCA 1 or 2 mutation carriers due to its favorable comparative cost-effectiveness.

Cost-effectiveness analysis of fecal microbiota transplantation for recurrent Clostridium difficile infection.

PubMed

Varier, Raghu U; Biltaji, Eman; Smith, Kenneth J; Roberts, Mark S; Kyle Jensen, M; LaFleur, Joanne; Nelson, Richard E

2015-04-01

Clostridium difficile infection (CDI) places a high burden on the US healthcare system. Recurrent CDI (RCDI) occurs frequently. Recently proposed guidelines from the American College of Gastroenterology (ACG) and the American Gastroenterology Association (AGA) include fecal microbiota transplantation (FMT) as a therapeutic option for RCDI. The purpose of this study was to estimate the cost-effectiveness of FMT compared with vancomycin for the treatment of RCDI in adults, specifically following guidelines proposed by the ACG and AGA. We constructed a decision-analytic computer simulation using inputs from the published literature to compare the standard approach using tapered vancomycin to FMT for RCDI from the third-party payer perspective. Our effectiveness measure was quality-adjusted life years (QALYs). Because simulated patients were followed for 90 days, discounting was not necessary. One-way and probabilistic sensitivity analyses were performed. Base-case analysis showed that FMT was less costly ($1,669 vs $3,788) and more effective (0.242 QALYs vs 0.235 QALYs) than vancomycin for RCDI. One-way sensitivity analyses showed that FMT was the dominant strategy (both less expensive and more effective) if cure rates for FMT and vancomycin were ≥70% and <91%, respectively, and if the cost of FMT was <$3,206. Probabilistic sensitivity analysis, varying all parameters simultaneously, showed that FMT was the dominant strategy over 10, 000 second-order Monte Carlo simulations. Our results suggest that FMT may be a cost-saving intervention in managing RCDI. Implementation of FMT for RCDI may help decrease the economic burden to the healthcare system.

Cost–effectiveness analysis of quadrivalent influenza vaccine in Spain

PubMed Central

García, Amos; Ortiz de Lejarazu, Raúl; Reina, Jordi; Callejo, Daniel; Cuervo, Jesús; Morano Larragueta, Raúl

2016-01-01

ABSTRACT Influenza has a major impact on healthcare systems and society, but can be prevented using vaccination. The World Health Organization (WHO) currently recommends that influenza vaccines should include at least two virus A and one virus B lineage (trivalent vaccine; TIV). A new quadrivalent vaccine (QIV), which includes an additional B virus strain, received regulatory approval and is now recommended by several countries. The present study estimates the cost-effectiveness of replacing TIVs with QIV for risk groups and elderly population in Spain. A static, lifetime, multi-cohort Markov model with a one-year cycle time was adapted to assess the costs and health outcomes associated with a switch from TIV to QIV. The model followed a cohort vaccinated each year according to health authority recommendations, for the duration of their lives. National epidemiological data allowed the determination of whether the B strain included in TIVs matched the circulating one. Societal perspective was considered, costs and outcomes were discounted at 3% and one-way and probabilistic sensitivity analyses were performed. Compared to TIVs, QIV reduced more influenza cases and influenza-related complications and deaths during periods of B-mismatch strains in the TIV. The incremental cost-effectiveness ratio (ICER) was 8,748€/quality-adjusted life year (QALY). One-way sensitivity analysis showed mismatch with the B lineage included in the TIV was the main driver for ICER. Probabilistic sensitivity analysis shows ICER below 30,000€/QALY in 96% of simulations. Replacing TIVs with QIV in Spain could improve influenza prevention by avoiding B virus mismatch and provide a cost-effective healthcare intervention. PMID:27184622

Evaluation of the cost-effectiveness of electrical stimulation therapy for pressure ulcers in spinal cord injury.

PubMed

Mittmann, Nicole; Chan, Brian C; Craven, B Cathy; Isogai, Pierre K; Houghton, Pamela

2011-06-01

To evaluate the incremental cost-effectiveness of electrical stimulation (ES) plus standard wound care (SWC) as compared with SWC only in a spinal cord injury (SCI) population with grade III/IV pressure ulcers (PUs) from the public payer perspective. A decision analytic model was constructed for a 1-year time horizon to determine the incremental cost-effectiveness of ES plus SWC to SWC in a cohort of participants with SCI and grade III/IV PUs. Model inputs for clinical probabilities were based on published literature. Model inputs, namely clinical probabilities and direct health system and medical resources were based on a randomized controlled trial of ES plus SWC versus SWC. Costs (Can $) included outpatient (clinic, home care, health professional) and inpatient management (surgery, complications). One way and probabilistic sensitivity (1000 Monte Carlo iterations) analyses were conducted. The perspective of this analysis is from a Canadian public health system payer. Model target population was an SCI cohort with grade III/IV PUs. Not applicable. Incremental cost per PU healed. ES plus SWC were associated with better outcomes and lower costs. There was a 16.4% increase in the PUs healed and a cost savings of $224 at 1 year. ES plus SWC were thus considered a dominant economic comparator. Probabilistic sensitivity analysis resulted in economic dominance for ES plus SWC in 62%, with another 35% having incremental cost-effectiveness ratios of $50,000 or less per PU healed. The largest driver of the economic model was the percentage of PU healed with ES plus SWC. The addition of ES to SWC improved healing in grade III/IV PU and reduced costs in an SCI population. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Cost effectiveness of imatinib compared with interferon-alpha or hydroxycarbamide for first-line treatment of chronic myeloid leukaemia.

PubMed

Dalziel, Kim; Round, Ali; Garside, Ruth; Stein, Ken

2005-01-01

To evaluate the cost utility of imatinib compared with interferon (IFN)-alpha or hydroxycarbamide (hydroxyurea) for first-line treatment of chronic myeloid leukaemia. A cost-utility (Markov) model within the setting of the UK NHS and viewed from a health system perspective was adopted. Transition probabilities and relative risks were estimated from published literature. Costs of drug treatment, outpatient care, bone marrow biopsies, radiography, blood transfusions and inpatient care were obtained from the British National Formulary and local hospital databases. Costs (pound, year 2001-03 values) were discounted at 6%. Quality-of-life (QOL) data were obtained from the published literature and discounted at 1.5%. The main outcome measure was cost per QALY gained. Extensive one-way sensitivity analyses were performed along with probabilistic (stochastic) analysis. The incremental cost-effectiveness ratio (ICER) of imatinib, compared with IFNalpha, was pound26,180 per QALY gained (one-way sensitivity analyses ranged from pound19,449 to pound51,870) and compared with hydroxycarbamide was pound86,934 per QALY (one-way sensitivity analyses ranged from pound69,701 to pound147,095) [ pound1=$US1.691=euro1.535 as at 31 December 2002].Based on the probabilistic sensitivity analysis, 50% of the ICERs for imatinib, compared with IFNalpha, fell below a threshold of approximately pound31,000 per QALY gained. Fifty percent of ICERs for imatinib, compared with hydroxycarbamide, fell below approximately pound95,000 per QALY gained. This model suggests, given its underlying data and assumptions, that imatinib may be moderately cost effective when compared with IFNalpha but considerably less cost effective when compared with hydroxycarbamide. There are, however, many uncertainties due to the lack of long-term data.

Cost-effectiveness of prucalopride in the treatment of chronic constipation in the Netherlands

PubMed Central

Nuijten, Mark J. C.; Dubois, Dominique J.; Joseph, Alain; Annemans, Lieven

2015-01-01

Objective: To assess the cost-effectiveness of prucalopride vs. continued laxative treatment for chronic constipation in patients in the Netherlands in whom laxatives have failed to provide adequate relief. Methods: A Markov model was developed to estimate the cost-effectiveness of prucalopride in patients with chronic constipation receiving standard laxative treatment from the perspective of Dutch payers in 2011. Data sources included published prucalopride clinical trials, published Dutch price/tariff lists, and national population statistics. The model simulated the clinical and economic outcomes associated with prucalopride vs. standard treatment and had a cycle length of 1 month and a follow-up time of 1 year. Response to treatment was defined as the proportion of patients who achieved “normal bowel function”. One-way and probabilistic sensitivity analyses were conducted to test the robustness of the base case. Results: In the base case analysis, the cost of prucalopride relative to continued laxative treatment was € 9015 per quality-adjusted life-year (QALY). Extensive sensitivity analyses and scenario analyses confirmed that the base case cost-effectiveness estimate was robust. One-way sensitivity analyses showed that the model was most sensitive in response to prucalopride; incremental cost-effectiveness ratios ranged from € 6475 to 15,380 per QALY. Probabilistic sensitivity analyses indicated that there is a greater than 80% probability that prucalopride would be cost-effective compared with continued standard treatment, assuming a willingness-to-pay threshold of € 20,000 per QALY from a Dutch societal perspective. A scenario analysis was performed for women only, which resulted in a cost-effectiveness ratio of € 7773 per QALY. Conclusion: Prucalopride was cost-effective in a Dutch patient population, as well as in a women-only subgroup, who had chronic constipation and who obtained inadequate relief from laxatives. PMID:25926794

Cost-utility Analysis: Thiopurines Plus Endoscopy-guided Biological Step-up Therapy is the Optimal Management of Postoperative Crohn's Disease.

PubMed

Candia, Roberto; Naimark, David; Sander, Beate; Nguyen, Geoffrey C

2017-11-01

Postoperative recurrence of Crohn's disease is common. This study sought to assess whether the postoperative management should be based on biological therapy alone or combined with thiopurines and whether the therapy should be started immediately after surgery or guided by either endoscopic or clinical recurrence. A Markov model was developed to estimate expected health outcomes in quality-adjusted life years (QALYs) and costs in Canadian dollars (CAD$) accrued by hypothetical patients with high recurrence risk after ileocolic resection. Eight strategies of postoperative management were evaluated. A lifetime time horizon, an annual discount rate of 5%, a societal perspective, and a cost-effectiveness threshold of 50,000 CAD$/QALY were assumed. Deterministic and probabilistic sensitivity analyses were conducted. The model was validated against randomized trials and historical cohorts. Three strategies dominated the others: endoscopy-guided full step-up therapy (14.80 QALYs, CAD$ 462,180), thiopurines immediately post-surgery plus endoscopy-guided biological step-up therapy (14.89 QALYs, CAD$ 464,099) and combination therapy immediately post-surgery (14.94 QALYs, CAD$ 483,685). The second strategy was the most cost-effective, assuming a cost-effectiveness threshold of 50,000 CAD$/QALY. Probabilistic sensitivity analysis showed that the second strategy has the highest probability of being the optimal alternative in all comparisons at cost-effectiveness thresholds from 30,000 to 100,000 CAD$/QALY. The strategies guided only by clinical recurrence and those using biologics alone were dominated. According to this decision analysis, thiopurines immediately after surgery and addition of biologics guided by endoscopic recurrence is the optimal strategy of postoperative management in patients with Crohn's disease with high risk of recurrence (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/IBD/B654).

Cost-effectiveness analysis of combination antifungal therapy with voriconazole and anidulafungin versus voriconazole monotherapy for primary treatment of invasive aspergillosis in Spain

PubMed Central

Grau, Santiago; Azanza, Jose Ramon; Ruiz, Isabel; Vallejo, Carlos; Mensa, Josep; Maertens, Johan; Heinz, Werner J; Barrueta, Jon Andoni; Peral, Carmen; Mesa, Francisco Jesús; Barrado, Miguel; Charbonneau, Claudie; Rubio-Rodríguez, Darío; Rubio-Terrés, Carlos

2017-01-01

Objective According to a recent randomized, double-blind clinical trial comparing the combination of voriconazole and anidulafungin (VOR+ANI) with VOR monotherapy for invasive aspergillosis (IA) in patients with hematologic disease or with hematopoietic stem cell transplant, mortality was lower after 6 weeks with VOR+ANI than with VOR monotherapy in a post hoc analysis of patients with galactomannan-based IA. The objective of this study was to compare the cost-effectiveness of VOR+ANI with VOR, from the perspective of hospitals in the Spanish National Health System. Methods An economic model with deterministic and probabilistic analyses was used to determine costs per life-year gained (LYG) for VOR+ANI versus VOR in patients with galactomannan-based IA. Mortality, adverse event rates, and life expectancy were obtained from clinical trial data. The costs (in 2015 euros [€]) of the drugs and the adverse event-related costs were obtained from Spanish sources. A Tornado plot and a Monte Carlo simulation (1,000 iterations) were used to assess uncertainty of all model variables. Results According to the deterministic analysis, for each patient treated with VOR+ANI compared with VOR monotherapy, there would be a total of 0.348 LYG (2.529 vs 2.181 years, respectively) at an incremental cost of €5,493 (€17,902 vs €12,409, respectively). Consequently, the additional cost per LYG with VOR+ANI compared with VOR would be €15,785. Deterministic sensitivity analyses confirmed the robustness of these findings. In the probabilistic analysis, the cost per LYG with VOR+ANI was €15,774 (95% confidence interval: €15,763–16,692). The probability of VOR+ANI being cost-effective compared with VOR was estimated at 82.5% and 91.9%, based on local cost-effectiveness thresholds of €30,000 and €45,000, respectively. Conclusion According to the present economic study, combination therapy with VOR+ANI is cost-effective as primary therapy of IA in galactomannan-positive patients in Spain who have hematologic disease or hematopoietic stem cell transplant, compared with VOR monotherapy. PMID:28115858

Establishing Cost-Effective Allocation of Proton Therapy for Breast Irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mailhot Vega, Raymond B.; Ishaq, Omar; Raldow, Ann

Purpose: Cardiac toxicity due to conventional breast radiation therapy (RT) has been extensively reported, and it affects both the life expectancy and quality of life of affected women. Given the favorable oncologic outcomes in most women irradiated for breast cancer, it is increasingly paramount to minimize treatment side effects and improve survivorship for these patients. Proton RT offers promise in limiting heart dose, but the modality is costly and access is limited. Using cost-effectiveness analysis, we provide a decision-making tool to help determine which breast cancer patients may benefit from proton RT referral. Methods and Materials: A Markov cohort model wasmore » constructed to compare the cost-effectiveness of proton versus photon RT for breast cancer management. The model was analyzed for different strata of women based on age (40 years, 50 years, and 60 years) and the presence or lack of cardiac risk factors (CRFs). Model entrants could have 1 of 3 health states: healthy, alive with coronary heart disease (CHD), or dead. Base-case analysis assumed CHD was managed medically. No difference in tumor control was assumed between arms. Probabilistic sensitivity analysis was performed to test model robustness and the influence of including catheterization as a downstream possibility within the health state of CHD. Results: Proton RT was not cost-effective in women without CRFs or a mean heart dose (MHD) <5 Gy. Base-case analysis noted cost-effectiveness for proton RT in women with ≥1 CRF at an approximate minimum MHD of 6 Gy with a willingness-to-pay threshold of $100,000/quality-adjusted life-year. For women with ≥1 CRF, probabilistic sensitivity analysis noted the preference of proton RT for an MHD ≥5 Gy with a similar willingness-to-pay threshold. Conclusions: Despite the cost of treatment, scenarios do exist whereby proton therapy is cost-effective. Referral for proton therapy may be cost-effective for patients with ≥1 CRF in cases for which photon plans are unable to achieve an MHD <5 Gy.« less

Economic analysis of routine neuromonitoring of recurrent laryngeal nerve in total thyroidectomy.

PubMed

Sanabria, Álvaro; Ramírez, Adonis

2015-01-01

Thyroidectomy is a common surgery. Routine searching of the recurrent laryngeal nerve is the most important strategy to avoid palsy. Neuromonitoring has been recommended to decrease recurrent laryngeal nerve palsy. To assess if neuromonitoring of recurrent laryngeal nerve during thyroidectomy is cost-effective in a developing country. We designed a decision analysis to assess the cost-effectiveness of recurrent laryngeal nerve neuromonitoring. For probabilities, we used data from a meta-analysis. Utility was measured using preference values. We considered direct costs. We conducted a deterministic and a probabilistic analysis. We did not find differences in utility between arms. The frequency of recurrent laryngeal nerve injury was 1% in the neuromonitor group and 1.6% for the standard group. Thyroidectomy without monitoring was the less expensive alternative. The incremental cost-effectiveness ratio was COP$ 9,112,065. Routine neuromonitoring in total thyroidectomy with low risk of recurrent laryngeal nerve injury is neither cost-useful nor cost-effective in the Colombian health system.

The cost-effectiveness of tumor-treating fields therapy in patients with newly diagnosed glioblastoma.

PubMed

Bernard-Arnoux, F; Lamure, M; Ducray, F; Aulagner, G; Honnorat, J; Armoiry, X

2016-08-01

There is strong concern about the costs associated with adding tumor-treating fields (TTF) therapy to standard first-line treatment for glioblastoma (GBM). Hence, we aimed to determine the cost-effectiveness of TTF therapy for the treatment of newly diagnosed patients with GBM. We developed a 3-health-state Markov model. The perspective was that of the French Health Insurance, and the horizon was lifetime. We calculated the transition probabilities from the survival parameters reported in the EF-14 trial. The main outcome measure was incremental effectiveness expressed as life-years gained (LYG). Input costs were derived from the literature. We calculated the incremental cost-effectiveness ratio (ICER) expressed as cost/LYG. We used 1-way deterministic and probabilistic sensitivity analysis to evaluate the model uncertainty. In the base-case analysis, adding TTF therapy to standard of care resulted in increases of life expectancy of 4.08 months (0.34 LYG) and €185 476 per patient. The ICER was €549 909/LYG. The discounted ICER was €596 411/LYG. Parameters with the most influence on ICER were the cost of TTF therapy, followed equally by overall survival and progression-free survival in both arms. The probabilistic sensitivity analysis showed a 95% confidence interval of the ICER of €447 017/LYG to €745 805/LYG with 0% chance to be cost-effective at a threshold of €100 000/LYG. The ICER of TTF therapy at first-line treatment is far beyond conventional thresholds due to the prohibitive announced cost of the device. Strong price regulation by health authorities could make this technology more affordable and consequently accessible to patients. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cost-effectiveness analysis of treatment strategies for initial Clostridium difficile infection.

PubMed

Varier, R U; Biltaji, E; Smith, K J; Roberts, M S; Jensen, M K; LaFleur, J; Nelson, R E

2014-12-01

Clostridium difficile infection (CDI) is costly. Current guidelines recommend metronidazole as first-line therapy and vancomycin as an alternative. Recurrence is common. Faecal microbiota transplantation (FMT) is an effective therapy for recurrent CDI (RCDI). This study explores the cost-effectiveness of FMT, vancomycin and metronidazole for initial CDI. We constructed a decision-analytic computer simulation using inputs from published literature to compare FMT with a 10-14-day course of oral metronidazole or vancomycin for initial CDI. Parameters included cure rates (baseline value (range)) for metronidazole (80% (65-85%)), vancomycin (90% (88-92%)) and FMT(91% (83-100%)). Direct costs of metronidazole, vancomycin and FMT, adjusted to 2011 dollars, were $57 ($43-72), $1347 ($1195-1499) and $1086 ($815-1358), respectively. Our effectiveness measure was quality-adjusted life years (QALYs). One-way and probabilistic sensitivity analyses were conducted from the third-party payer perspective. Analysis using baseline values showed that FMT($1669, 0.242 QALYs) dominated (i.e. was less costly and more effective) vancomycin ($1890, 0.241 QALYs). FMT was more costly and more effective than metronidazole ($1167, 0.238 QALYs), yielding an incremental cost-effectiveness ratio (ICER) of $124 964/QALY. One-way sensitivity analyses showed that metronidazole dominated both strategies if its probability of cure were >90%; FMT dominated if it cost <$584. In a probabilistic sensitivity analysis at a willingness-to-pay threshold of $100 000/QALY, metronidazole was favoured in 55% of model iterations; FMT was favoured in 38%. Metronidazole, as the first-line treatment for CDIs, is less costly. FMT and vancomycin are more effective. However, FMT is less likely to be economically favourable, and vancomycin is unlikely to be favourable as first-line therapy when compared with FMT. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Cost effectiveness of fingolimod, teriflunomide, dimethyl fumarate and intramuscular interferon-β1a in relapsing-remitting multiple sclerosis.

PubMed

Zhang, Xinke; Hay, Joel W; Niu, Xiaoli

2015-01-01

The aim of the study was to compare the cost effectiveness of fingolimod, teriflunomide, dimethyl fumarate, and intramuscular (IM) interferon (IFN)-β(1a) as first-line therapies in the treatment of patients with relapsing-remitting multiple sclerosis (RRMS). A Markov model was developed to evaluate the cost effectiveness of disease-modifying drugs (DMDs) from a US societal perspective. The time horizon in the base case was 5 years. The primary outcome was incremental net monetary benefit (INMB), and the secondary outcome was incremental cost-effectiveness ratio (ICER). The base case INMB willingness-to-pay (WTP) threshold was assumed to be US$150,000 per quality-adjusted life year (QALY), and the costs were in 2012 US dollars. One-way sensitivity analyses and probabilistic sensitivity analysis were conducted to test the robustness of the model results. Dimethyl fumarate dominated all other therapies over the range of WTPs, from US$0 to US$180,000. Compared with IM IFN-β(1a), at a WTP of US$150,000, INMBs were estimated at US$36,567, US$49,780, and US$80,611 for fingolimod, teriflunomide, and dimethyl fumarate, respectively. The ICER of fingolimod versus teriflunomide was US$3,201,672. One-way sensitivity analyses demonstrated the model results were sensitive to the acquisition costs of DMDs and the time horizon, but in most scenarios, cost-effectiveness rankings remained stable. Probabilistic sensitivity analysis showed that for more than 90% of the simulations, dimethyl fumarate was the optimal therapy across all WTP values. The three oral therapies were favored in the cost-effectiveness analysis. Of the four DMDs, dimethyl fumarate was a dominant therapy to manage RRMS. Apart from dimethyl fumarate, teriflunomide was the most cost-effective therapy compared with IM IFN-β(1a), with an ICER of US$7,115.

Learning classification with auxiliary probabilistic information

PubMed Central

Nguyen, Quang; Valizadegan, Hamed; Hauskrecht, Milos

2012-01-01

Finding ways of incorporating auxiliary information or auxiliary data into the learning process has been the topic of active data mining and machine learning research in recent years. In this work we study and develop a new framework for classification learning problem in which, in addition to class labels, the learner is provided with an auxiliary (probabilistic) information that reflects how strong the expert feels about the class label. This approach can be extremely useful for many practical classification tasks that rely on subjective label assessment and where the cost of acquiring additional auxiliary information is negligible when compared to the cost of the example analysis and labelling. We develop classification algorithms capable of using the auxiliary information to make the learning process more efficient in terms of the sample complexity. We demonstrate the benefit of the approach on a number of synthetic and real world data sets by comparing it to the learning with class labels only. PMID:25309141

Cost Effectiveness of Genotype-Guided Warfarin Dosing in Patients with Mechanical Heart Valve Replacement Under the Fee-for-Service System.

PubMed

Kim, Dong-Jin; Kim, Ho-Sook; Oh, Minkyung; Kim, Eun-Young; Shin, Jae-Gook

2017-10-01

Although studies assessing the cost effectiveness of genotype-guided warfarin dosing for the management of atrial fibrillation, deep vein thrombosis, and pulmonary embolism have been reported, no publications have addressed genotype-guided warfarin therapy in mechanical heart valve replacement (MHVR) patients or genotype-guided warfarin therapy under the fee-for-service (FFS) insurance system. The aim of this study was to evaluate the cost effectiveness of genotype-guided warfarin dosing in patients with MHVR under the FFS system from the Korea healthcare sector perspective. A decision-analytic Markov model was developed to evaluate the cost effectiveness of genotype-guided warfarin dosing compared with standard dosing. Estimates of clinical adverse event rates and health state utilities were derived from the published literature. The outcome measure was the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY). One-way and probabilistic sensitivity analyses were performed to explore the range of plausible results. In a base-case analysis, genotype-guided warfarin dosing was associated with marginally higher QALYs than standard warfarin dosing (6.088 vs. 6.083, respectively), at a slightly higher cost (US$6.8) (year 2016 values). The ICER was US$1356.2 per QALY gained. In probabilistic sensitivity analysis, there was an 82.7% probability that genotype-guided dosing was dominant compared with standard dosing, and a 99.8% probability that it was cost effective at a willingness-to-pay threshold of US$50,000 per QALY gained. Compared with only standard warfarin therapy, genotype-guided warfarin dosing was cost effective in MHVR patients under the FFS insurance system.

Cost Effectiveness of Free Access to Smoking Cessation Treatment in France Considering the Economic Burden of Smoking-Related Diseases

PubMed Central

Cadier, Benjamin; Durand-Zaleski, Isabelle; Thomas, Daniel; Chevreul, Karine

2016-01-01

Context In France more than 70,000 deaths from diseases related to smoking are recorded each year, and since 2005 prevalence of tobacco has increased. Providing free access to smoking cessation treatment would reduce this burden. The aim of our study was to estimate the incremental cost-effectiveness ratios (ICER) of providing free access to cessation treatment taking into account the cost offsets associated with the reduction of the three main diseases related to smoking: lung cancer, chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). To measure the financial impact of such a measure we also conducted a probabilistic budget impact analysis. Methods and Findings We performed a cost-effectiveness analysis using a Markov state-transition model that compared free access to cessation treatment to the existing coverage of €50 provided by the French statutory health insurance, taking into account the cost offsets among current French smokers aged 15–75 years. Our results were expressed by the incremental cost-effectiveness ratio in 2009 Euros per life year gained (LYG) at the lifetime horizon. We estimated a base case scenario and carried out a Monte Carlo sensitivity analysis to account for uncertainty. Assuming a participation rate of 7.3%, the ICER value for free access to cessation treatment was €3,868 per LYG in the base case. The variation of parameters provided a range of ICER values from -€736 to €15,715 per LYG. In 99% of cases, the ICER for full coverage was lower than €11,187 per LYG. The probabilistic budget impact analysis showed that the potential cost saving for lung cancer, COPD and CVD ranges from €15 million to €215 million at the five-year horizon for an initial cessation treatment cost of €125 million to €421 million. Conclusion The results suggest that providing medical support to smokers in their attempts to quit is very cost-effective and may even result in cost savings. PMID:26909802

Cost-effectiveness of endovascular versus open repair of acute complicated type B aortic dissections.

PubMed

Luebke, Thomas; Brunkwall, Jan

2014-05-01

This study weighed the cost and benefit of thoracic endovascular aortic repair (TEVAR) vs open repair (OR) in the treatment of an acute complicated type B aortic dissection by (TBAD) estimating the cost-effectiveness to determine an optimal treatment strategy based on the best currently available evidence. A cost-utility analysis from the perspective of the health system payer was performed using a decision analytic model. Within this model, the 1-year survival, quality-adjusted life-years (QALYs), and costs for a hypothetical cohort of patients with an acute complicated TBAD managed with TEVAR or OR were evaluated. Clinical effectiveness data, cost data, and transitional probabilities of different health states were derived from previously published high-quality studies or meta-analyses. Probabilistic sensitivity analyses were performed on uncertain model parameters. The base-case analysis showed, in terms of QALYs, that OR appeared to be more expensive (incremental cost of €17,252.60) and less effective (-0.19 QALYs) compared with TEVAR; hence, in terms of the incremental cost-effectiveness ratio, OR was dominated by TEVAR. As a result, the incremental cost-effectiveness ratio (ie, the cost per life-year saved) was not calculated. The average cost-effectiveness ratio of TEVAR and OR per QALY gained was €56,316.79 and €108,421.91, respectively. In probabilistic sensitivity analyses, TEVAR was economically dominant in 100% of cases. The probability that TEVAR was economically attractive at a willingness-to-pay threshold of €50,000/QALY gained was 100%. The present results suggest that TEVAR yielded more QALYs and was associated with lower 1-year costs compared with OR in patients with an acute complicated TBAD. As a result, from the cost-effectiveness point of view, TEVAR is the dominant therapy over OR for this disease under the predefined conditions. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Screen or not to screen for peripheral arterial disease: guidance from a decision model.

PubMed

Vaidya, Anil; Joore, Manuela A; Ten Cate-Hoek, Arina J; Ten Cate, Hugo; Severens, Johan L

2014-01-29

Asymptomatic Peripheral Arterial Disease (PAD) is associated with greater risk of acute cardiovascular events. This study aims to determine the cost-effectiveness of one time only PAD screening using Ankle Brachial Index (ABI) test and subsequent anti platelet preventive treatment (low dose aspirin or clopidogrel) in individuals at high risk for acute cardiovascular events compared to no screening and no treatment using decision analytic modelling. A probabilistic Markov model was developed to evaluate the life time cost-effectiveness of the strategy of selective PAD screening and consequent preventive treatment compared to no screening and no preventive treatment. The analysis was conducted from the Dutch societal perspective and to address decision uncertainty, probabilistic sensitivity analysis was performed. Results were based on average values of 1000 Monte Carlo simulations and using discount rates of 1.5% and 4% for effects and costs respectively. One way sensitivity analyses were performed to identify the two most influential model parameters affecting model outputs. Then, a two way sensitivity analysis was conducted for combinations of values tested for these two most influential parameters. For the PAD screening strategy, life years and quality adjusted life years gained were 21.79 and 15.66 respectively at a lifetime cost of 26,548 Euros. Compared to no screening and treatment (20.69 life years, 15.58 Quality Adjusted Life Years, 28,052 Euros), these results indicate that PAD screening and treatment is a dominant strategy. The cost effectiveness acceptability curves show 88% probability of PAD screening being cost effective at the Willingness To Pay (WTP) threshold of 40000 Euros. In a scenario analysis using clopidogrel as an alternative anti-platelet drug, PAD screening strategy remained dominant. This decision analysis suggests that targeted ABI screening and consequent secondary prevention of cardiovascular events using low dose aspirin or clopidogrel in the identified patients is a cost-effective strategy. Implementation of targeted PAD screening and subsequent treatment in primary care practices and in public health programs is likely to improve the societal health and to save health care costs by reducing catastrophic cardiovascular events.

Relative potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications

NASA Technical Reports Server (NTRS)

Borden, C. S.; Schwartz, D. L.

1984-01-01

The purpose of this study is to assess the relative economic potentials of concenrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications in the mid-1990's. Specific objectives of this study are to provide information on concentrator photovoltaic collector probabilistic price and efficiency levels to illustrate critical areas of R&D for concentrator cells and collectors, and to compare concentrator and flat-plate PV price and efficiency alternatives for several locations, based on their implied costs of energy. To deal with the uncertainties surrounding research and development activities in general, a probabilistic assessment of commercially achievable concentrator photovoltaic collector efficiencies and prices (at the factory loading dock) is performed. The results of this projection of concentrator photovoltaic technology are then compared with a previous flat-plate module price analysis (performed early in 1983). To focus this analysis on specific collector alternatives and their implied energy costs for different locations, similar two-axis tracking designs are assumed for both concentrator and flat-plate options.

Cost-Loss Analysis of Ensemble Solar Wind Forecasting: Space Weather Use of Terrestrial Weather Tools

NASA Astrophysics Data System (ADS)

Henley, E. M.; Pope, E. C. D.

2017-12-01

This commentary concerns recent work on solar wind forecasting by Owens and Riley (2017). The approach taken makes effective use of tools commonly used in terrestrial weather—notably, via use of a simple model—generation of an "ensemble" forecast, and application of a "cost-loss" analysis to the resulting probabilistic information, to explore the benefit of this forecast to users with different risk appetites. This commentary aims to highlight these useful techniques to the wider space weather audience and to briefly discuss the general context of application of terrestrial weather approaches to space weather.

Cost-effectiveness of left ventricular assist devices for patients with end-stage heart failure: analysis of the French hospital discharge database.

PubMed

Tadmouri, Abir; Blomkvist, Josefin; Landais, Cécile; Seymour, Jerome; Azmoun, Alexandre

2018-02-01

Although left ventricular assist devices (LVADs) are currently approved for coverage and reimbursement in France, no French cost-effectiveness (CE) data are available to support this decision. This study aimed at estimating the CE of LVAD compared with medical management in the French health system. Individual patient data from the 'French hospital discharge database' (Medicalization of information systems program) were analysed using Kaplan-Meier method. Outcomes were time to death, time to heart transplantation (HTx), and time to death after HTx. A micro-costing method was used to calculate the monthly costs extracted from the Program for the Medicalization of Information Systems. A multistate Markov monthly cycle model was developed to assess CE. The analysis over a lifetime horizon was performed from the perspective of the French healthcare payer; discount rates were 4%. Probabilistic and deterministic sensitivity analyses were performed. Outcomes were quality-adjusted life years (QALYs) and incremental CE ratio (ICER). Mean QALY for an LVAD patient was 1.5 at a lifetime cost of €190 739, delivering a probabilistic ICER of €125 580/QALY [95% confidence interval: 105 587 to 150 314]. The sensitivity analysis showed that the ICER was mainly sensitive to two factors: (i) the high acquisition cost of the device and (ii) the device performance in terms of patient survival. Our economic evaluation showed that the use of LVAD in patients with end-stage heart failure yields greater benefit in terms of survival than medical management at an extra lifetime cost exceeding the €100 000/QALY. Technological advances and device costs reduction shall hence lead to an improvement in overall CE. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Probabilistic Teleportation of an Arbitrary Three-Level Two-Particle State and Classical Communication Cost

NASA Astrophysics Data System (ADS)

Dai, Hong-Yi; Kuang, Le-Man; Li, Cheng-Zu

2005-07-01

We propose a scheme to probabilistically teleport an unknown arbitrary three-level two-particle state by using two partial entangled two-particle states of three-level as the quantum channel. The classical communication cost required in the ideal probabilistic teleportation process is also calculated. This scheme can be directly generalized to teleport an unknown and arbitrary three-level K-particle state by using K partial entangled two-particle states of three-level as the quantum channel. The project supported by National Fundamental Research Program of China under Grant No. 2001CB309310, National Natural Science Foundation of China under Grant Nos. 10404039 and 10325523

Cost-effectiveness of minimally invasive sacroiliac joint fusion.

PubMed

Cher, Daniel J; Frasco, Melissa A; Arnold, Renée Jg; Polly, David W

2016-01-01

Sacroiliac joint (SIJ) disorders are common in patients with chronic lower back pain. Minimally invasive surgical options have been shown to be effective for the treatment of chronic SIJ dysfunction. To determine the cost-effectiveness of minimally invasive SIJ fusion. Data from two prospective, multicenter, clinical trials were used to inform a Markov process cost-utility model to evaluate cumulative 5-year health quality and costs after minimally invasive SIJ fusion using triangular titanium implants or non-surgical treatment. The analysis was performed from a third-party perspective. The model specifically incorporated variation in resource utilization observed in the randomized trial. Multiple one-way and probabilistic sensitivity analyses were performed. SIJ fusion was associated with a gain of approximately 0.74 quality-adjusted life years (QALYs) at a cost of US$13,313 per QALY gained. In multiple one-way sensitivity analyses all scenarios resulted in an incremental cost-effectiveness ratio (ICER) <$26,000/QALY. Probabilistic analyses showed a high degree of certainty that the maximum ICER for SIJ fusion was less than commonly selected thresholds for acceptability (mean ICER =$13,687, 95% confidence interval $5,162-$28,085). SIJ fusion provided potential cost savings per QALY gained compared to non-surgical treatment after a treatment horizon of greater than 13 years. Compared to traditional non-surgical treatments, SIJ fusion is a cost-effective, and, in the long term, cost-saving strategy for the treatment of SIJ dysfunction due to degenerative sacroiliitis or SIJ disruption.

Cost-effectiveness of minimally invasive sacroiliac joint fusion

PubMed Central

Cher, Daniel J; Frasco, Melissa A; Arnold, Renée JG; Polly, David W

2016-01-01

Background Sacroiliac joint (SIJ) disorders are common in patients with chronic lower back pain. Minimally invasive surgical options have been shown to be effective for the treatment of chronic SIJ dysfunction. Objective To determine the cost-effectiveness of minimally invasive SIJ fusion. Methods Data from two prospective, multicenter, clinical trials were used to inform a Markov process cost-utility model to evaluate cumulative 5-year health quality and costs after minimally invasive SIJ fusion using triangular titanium implants or non-surgical treatment. The analysis was performed from a third-party perspective. The model specifically incorporated variation in resource utilization observed in the randomized trial. Multiple one-way and probabilistic sensitivity analyses were performed. Results SIJ fusion was associated with a gain of approximately 0.74 quality-adjusted life years (QALYs) at a cost of US$13,313 per QALY gained. In multiple one-way sensitivity analyses all scenarios resulted in an incremental cost-effectiveness ratio (ICER) <$26,000/QALY. Probabilistic analyses showed a high degree of certainty that the maximum ICER for SIJ fusion was less than commonly selected thresholds for acceptability (mean ICER =$13,687, 95% confidence interval $5,162–$28,085). SIJ fusion provided potential cost savings per QALY gained compared to non-surgical treatment after a treatment horizon of greater than 13 years. Conclusion Compared to traditional non-surgical treatments, SIJ fusion is a cost-effective, and, in the long term, cost-saving strategy for the treatment of SIJ dysfunction due to degenerative sacroiliitis or SIJ disruption. PMID:26719717

Incremental cost and cost-effectiveness of low-dose, high-frequency training in basic emergency obstetric and newborn care as compared to status quo: part of a cluster-randomized training intervention evaluation in Ghana.

PubMed

Willcox, Michelle; Harrison, Heather; Asiedu, Amos; Nelson, Allyson; Gomez, Patricia; LeFevre, Amnesty

2017-12-06

Low-dose, high-frequency (LDHF) training is a new approach best practices to improve clinical knowledge, build and retain competency, and transfer skills into practice after training. LDHF training in Ghana is an opportunity to build health workforce capacity in critical areas of maternal and newborn health and translate improved capacity into better health outcomes. This study examined the costs of an LDHF training approach for basic emergency obstetric and newborn care and calculates the incremental cost-effectiveness of the LDHF training program for health outcomes of newborn survival, compared to the status quo alternative of no training. The costs of LDHF were compared to costs of traditional workshop-based training per provider trained. Retrospective program cost analysis with activity-based costing was used to measure all resources of the LDHF training program over a 3-year analytic time horizon. Economic costs were estimated from financial records, informant interviews, and regional market prices. Health effects from the program's impact evaluation were used to model lives saved and disability-adjusted life years (DALYs) averted. Uncertainty analysis included one-way and probabilistic sensitivity analysis to explore incremental cost-effectiveness results when fluctuating key parameters. For the 40 health facilities included in the evaluation, the total LDHF training cost was $823,134. During the follow-up period after the first LDHF training-1 year at each participating facility-approximately 544 lives were saved. With deterministic calculation, these findings translate to $1497.77 per life saved or $53.07 per DALY averted. Probabilistic sensitivity analysis, with mean incremental cost-effectiveness ratio of $54.79 per DALY averted ($24.42-$107.01), suggests the LDHF training program as compared to no training has 100% probability of being cost-effective above a willingness to pay threshold of $1480, Ghana's gross national income per capita in 2015. This study provides insight into the investment of LDHF training and value for money of this approach to training in-service providers on basic emergency obstetric and newborn care. The LDHF training approach should be considered for expansion in Ghana and integrated into existing in-service training programs and health system organizational structures for lower cost and more efficiency at scale.

Transactional problem content in cost discounting: parallel effects for probability and delay.

PubMed

Jones, Stephen; Oaksford, Mike

2011-05-01

Four experiments investigated the effects of transactional content on temporal and probabilistic discounting of costs. Kusev, van Schaik, Ayton, Dent, and Chater (2009) have shown that content other than gambles can alter decision-making behavior even when associated value and probabilities are held constant. Transactions were hypothesized to lead to similar effects because the cost to a purchaser always has a linked gain, the purchased commodity. Gain amount has opposite effects on delay and probabilistic discounting (e.g., Benzion, Rapoport, & Yagil, 1989; Green, Myerson, & Ostaszewski, 1999), a finding that is not consistent with descriptive decision theory (Kahneman & Tversky, 1979; Loewenstein & Prelec, 1992). However, little or no effect on discounting has been observed for losses or costs. Experiment 1, using transactions, showed parallel effects for temporal and probabilistic discounting: Smaller amounts were discounted more than large amounts. As the cost rises, people value the commodity more, and they consequently discount less. Experiment 2 ruled out a possible methodological cause for this effect. Experiment 3 replicated Experiment 1. Experiment 4, using gambles, showed no effect for temporal discounting, because of the absence of the linked gain, but the same effect for probabilistic discounting, because prospects implicitly introduce a linked gain (Green et al., 1999; Prelec & Loewenstein, 1991). As found by Kusev et al. (2009), these findings are not consistent with decision theory and suggest closer attention should be paid to the effects of content on decision making.

Cost-effectiveness of population based BRCA testing with varying Ashkenazi Jewish ancestry.

PubMed

Manchanda, Ranjit; Patel, Shreeya; Antoniou, Antonis C; Levy-Lahad, Ephrat; Turnbull, Clare; Evans, D Gareth; Hopper, John L; Macinnis, Robert J; Menon, Usha; Jacobs, Ian; Legood, Rosa

2017-11-01

Population-based BRCA1/BRCA2 testing has been found to be cost-effective compared with family history-based testing in Ashkenazi-Jewish women were >30 years old with 4 Ashkenazi-Jewish grandparents. However, individuals may have 1, 2, or 3 Ashkenazi-Jewish grandparents, and cost-effectiveness data are lacking at these lower BRCA prevalence estimates. We present an updated cost-effectiveness analysis of population BRCA1/BRCA2 testing for women with 1, 2, and 3 Ashkenazi-Jewish grandparents. Decision analysis model. Lifetime costs and effects of population and family history-based testing were compared with the use of a decision analysis model. 56% BRCA carriers are missed by family history criteria alone. Analyses were conducted for United Kingdom and United States populations. Model parameters were obtained from the Genetic Cancer Prediction through Population Screening trial and published literature. Model parameters and BRCA population prevalence for individuals with 3, 2, or 1 Ashkenazi-Jewish grandparent were adjusted for the relative frequency of BRCA mutations in the Ashkenazi-Jewish and general populations. Incremental cost-effectiveness ratios were calculated for all Ashkenazi-Jewish grandparent scenarios. Costs, along with outcomes, were discounted at 3.5%. The time horizon of the analysis is "life-time," and perspective is "payer." Probabilistic sensitivity analysis evaluated model uncertainty. Population testing for BRCA mutations is cost-saving in Ashkenazi-Jewish women with 2, 3, or 4 grandparents (22-33 days life-gained) in the United Kingdom and 1, 2, 3, or 4 grandparents (12-26 days life-gained) in the United States populations, respectively. It is also extremely cost-effective in women in the United Kingdom with just 1 Ashkenazi-Jewish grandparent with an incremental cost-effectiveness ratio of £863 per quality-adjusted life-years and 15 days life gained. Results show that population-testing remains cost-effective at the £20,000-30000 per quality-adjusted life-years and $100,000 per quality-adjusted life-years willingness-to-pay thresholds for all 4 Ashkenazi-Jewish grandparent scenarios, with ≥95% simulations found to be cost-effective on probabilistic sensitivity analysis. Population-testing remains cost-effective in the absence of reduction in breast cancer risk from oophorectomy and at lower risk-reducing mastectomy (13%) or risk-reducing salpingo-oophorectomy (20%) rates. Population testing for BRCA mutations with varying levels of Ashkenazi-Jewish ancestry is cost-effective in the United Kingdom and the United States. These results support population testing in Ashkenazi-Jewish women with 1-4 Ashkenazi-Jewish grandparent ancestry. Copyright © 2017 Elsevier Inc. All rights reserved.

Cost-effectiveness analysis of offering free leisure centre memberships to physically inactive members of the public receiving state benefits: a case study.

PubMed

Verhoef, Talitha I; Trend, Verena; Kelly, Barry; Robinson, Nigel; Fox, Paul; Morris, Stephen

2016-07-22

We evaluated the cost-effectiveness of the Give-it-a-Go programme, which offers free leisure centre memberships to physically inactive members of the public in a single London Borough receiving state benefits. A decision analytic Markov model was developed to analyse lifetime costs and quality-adjusted life-years (QALYs) of 1025 people recruited to the intervention versus no intervention. In the intervention group, people were offered 4 months of free membership at a leisure centre. Physical activity levels were assessed at 0 and 4 months using the International Physical Activity Questionnaire (IPAQ). Higher levels of physical activity were assumed to decrease the risk of coronary heart disease, stroke and diabetes mellitus type II, as well as improve mental health. Costs were assessed from a National Health Service (NHS) perspective. Uncertainty was assessed using one-way and probabilistic sensitivity analyses. One-hundred fifty nine participants (15.5 %) completed the programme by attending the leisure centre for 4 months. Compared with no intervention, Give it a Go increased costs by £67.25 and QALYs by 0.0033 (equivalent to 1.21 days in full health) per recruited person. The incremental costs per QALY gained were £20,347. The results were highly sensitive to the magnitude of mental health gain due to physical activity and the duration of the effect of the programme (1 year in the base case analysis). When the mental health gain was omitted from the analysis, the incremental cost per QALY gained increased to almost £1.5 million. In the probabilistic sensitivity analysis, the incremental costs per QALY gained were below £20,000 in 39 % of the 5000 simulations. Give it a Go did not significantly increase life-expectancy, but had a positive influence on quality of life due to the mental health gain of physical activity. If the increase in physical activity caused by Give it a Go lasts for more than 1 year, the programme would be cost-effective given a willingness to pay for a QALY of £20,000.

A preliminary cost-effectiveness analysis of hepatitis E vaccination among pregnant women in epidemic regions.

PubMed

Zhao, Yueyuan; Zhang, Xuefeng; Zhu, Fengcai; Jin, Hui; Wang, Bei

2016-08-02

Objective To estimate the cost-effectiveness of hepatitis E vaccination among pregnant women in epidemic regions. Methods A decision tree model was constructed to evaluate the cost-effectiveness of 3 hepatitis E virus vaccination strategies from societal perspectives. The model parameters were estimated on the basis of published studies and experts' experience. Sensitivity analysis was used to evaluate the uncertainties of the model. Results Vaccination was more economically effective on the basis of the incremental cost-effectiveness ratio (ICER< 3 times China's per capital gross domestic product/quality-adjusted life years); moreover, screening and vaccination had higher QALYs and lower costs compared with universal vaccination. No parameters significantly impacted ICER in one-way sensitivity analysis, and probabilistic sensitivity analysis also showed screening and vaccination to be the dominant strategy. Conclusion Screening and vaccination is the most economical strategy for pregnant women in epidemic regions; however, further studies are necessary to confirm the efficacy and safety of the hepatitis E vaccines.

Probabilistic distance-based quantizer design for distributed estimation

NASA Astrophysics Data System (ADS)

Kim, Yoon Hak

2016-12-01

We consider an iterative design of independently operating local quantizers at nodes that should cooperate without interaction to achieve application objectives for distributed estimation systems. We suggest as a new cost function a probabilistic distance between the posterior distribution and its quantized one expressed as the Kullback Leibler (KL) divergence. We first present the analysis that minimizing the KL divergence in the cyclic generalized Lloyd design framework is equivalent to maximizing the logarithmic quantized posterior distribution on the average which can be further computationally reduced in our iterative design. We propose an iterative design algorithm that seeks to maximize the simplified version of the posterior quantized distribution and discuss that our algorithm converges to a global optimum due to the convexity of the cost function and generates the most informative quantized measurements. We also provide an independent encoding technique that enables minimization of the cost function and can be efficiently simplified for a practical use of power-constrained nodes. We finally demonstrate through extensive experiments an obvious advantage of improved estimation performance as compared with the typical designs and the novel design techniques previously published.

Low-Dimensional Statistics of Anatomical Variability via Compact Representation of Image Deformations.

PubMed

Zhang, Miaomiao; Wells, William M; Golland, Polina

2016-10-01

Using image-based descriptors to investigate clinical hypotheses and therapeutic implications is challenging due to the notorious "curse of dimensionality" coupled with a small sample size. In this paper, we present a low-dimensional analysis of anatomical shape variability in the space of diffeomorphisms and demonstrate its benefits for clinical studies. To combat the high dimensionality of the deformation descriptors, we develop a probabilistic model of principal geodesic analysis in a bandlimited low-dimensional space that still captures the underlying variability of image data. We demonstrate the performance of our model on a set of 3D brain MRI scans from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Our model yields a more compact representation of group variation at substantially lower computational cost than models based on the high-dimensional state-of-the-art approaches such as tangent space PCA (TPCA) and probabilistic principal geodesic analysis (PPGA).

Cost-Effectiveness Analysis of Five Competing Strategies for the Management of Multiple Recurrent Community-Onset Clostridium difficile Infection in France

PubMed Central

Galperine, Tatiana; Denies, Fanette; Lannoy, Damien; Lenne, Xavier; Odou, Pascal; Guery, Benoit; Dervaux, Benoit

2017-01-01

Background Clostridium difficile infection (CDI) is characterized by high rates of recurrence, resulting in substantial health care costs. The aim of this study was to analyze the cost-effectiveness of treatments for the management of second recurrence of community-onset CDI in France. Methods We developed a decision-analytic simulation model to compare 5 treatments for the management of second recurrence of community-onset CDI: pulsed-tapered vancomycin, fidaxomicin, fecal microbiota transplantation (FMT) via colonoscopy, FMT via duodenal infusion, and FMT via enema. The model outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life year (QALY) among the 5 treatments. ICERs were interpreted using a willingness-to-pay threshold of €32,000/QALY. Uncertainty was evaluated through deterministic and probabilistic sensitivity analyses. Results Three strategies were on the efficiency frontier: pulsed-tapered vancomycin, FMT via enema, and FMT via colonoscopy, in order of increasing effectiveness. FMT via duodenal infusion and fidaxomicin were dominated (i.e. less effective and costlier) by FMT via colonoscopy and FMT via enema. FMT via enema compared with pulsed-tapered vancomycin had an ICER of €18,092/QALY. The ICER for FMT via colonoscopy versus FMT via enema was €73,653/QALY. Probabilistic sensitivity analysis with 10,000 Monte Carlo simulations showed that FMT via enema was the most cost-effective strategy in 58% of simulations and FMT via colonoscopy was favored in 19% at a willingness-to-pay threshold of €32,000/QALY. Conclusions FMT via enema is the most cost-effective initial strategy for the management of second recurrence of community-onset CDI at a willingness-to-pay threshold of €32,000/QALY. PMID:28103289

Cost-Effectiveness Analysis of Five Competing Strategies for the Management of Multiple Recurrent Community-Onset Clostridium difficile Infection in France.

PubMed

Baro, Emilie; Galperine, Tatiana; Denies, Fanette; Lannoy, Damien; Lenne, Xavier; Odou, Pascal; Guery, Benoit; Dervaux, Benoit

2017-01-01

Clostridium difficile infection (CDI) is characterized by high rates of recurrence, resulting in substantial health care costs. The aim of this study was to analyze the cost-effectiveness of treatments for the management of second recurrence of community-onset CDI in France. We developed a decision-analytic simulation model to compare 5 treatments for the management of second recurrence of community-onset CDI: pulsed-tapered vancomycin, fidaxomicin, fecal microbiota transplantation (FMT) via colonoscopy, FMT via duodenal infusion, and FMT via enema. The model outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life year (QALY) among the 5 treatments. ICERs were interpreted using a willingness-to-pay threshold of €32,000/QALY. Uncertainty was evaluated through deterministic and probabilistic sensitivity analyses. Three strategies were on the efficiency frontier: pulsed-tapered vancomycin, FMT via enema, and FMT via colonoscopy, in order of increasing effectiveness. FMT via duodenal infusion and fidaxomicin were dominated (i.e. less effective and costlier) by FMT via colonoscopy and FMT via enema. FMT via enema compared with pulsed-tapered vancomycin had an ICER of €18,092/QALY. The ICER for FMT via colonoscopy versus FMT via enema was €73,653/QALY. Probabilistic sensitivity analysis with 10,000 Monte Carlo simulations showed that FMT via enema was the most cost-effective strategy in 58% of simulations and FMT via colonoscopy was favored in 19% at a willingness-to-pay threshold of €32,000/QALY. FMT via enema is the most cost-effective initial strategy for the management of second recurrence of community-onset CDI at a willingness-to-pay threshold of €32,000/QALY.

Cost Effectiveness of Ofatumumab Plus Chlorambucil in First-Line Chronic Lymphocytic Leukaemia in Canada.

PubMed

Herring, William; Pearson, Isobel; Purser, Molly; Nakhaipour, Hamid Reza; Haiderali, Amin; Wolowacz, Sorrel; Jayasundara, Kavisha

2016-01-01

Our objective was to estimate the cost effectiveness of ofatumumab plus chlorambucil (OChl) versus chlorambucil in patients with chronic lymphocytic leukaemia for whom fludarabine-based therapies are considered inappropriate from the perspective of the publicly funded healthcare system in Canada. A semi-Markov model (3-month cycle length) used survival curves to govern progression-free survival (PFS) and overall survival (OS). Efficacy and safety data and health-state utility values were estimated from the COMPLEMENT-1 trial. Post-progression treatment patterns were based on clinical guidelines, Canadian treatment practices and published literature. Total and incremental expected lifetime costs (in Canadian dollars [$Can], year 2013 values), life-years and quality-adjusted life-years (QALYs) were computed. Uncertainty was assessed via deterministic and probabilistic sensitivity analyses. The discounted lifetime health and economic outcomes estimated by the model showed that, compared with chlorambucil, first-line treatment with OChl led to an increase in QALYs (0.41) and total costs ($Can27,866) and to an incremental cost-effectiveness ratio (ICER) of $Can68,647 per QALY gained. In deterministic sensitivity analyses, the ICER was most sensitive to the modelling time horizon and to the extrapolation of OS treatment effects beyond the trial duration. In probabilistic sensitivity analysis, the probability of cost effectiveness at a willingness-to-pay threshold of $Can100,000 per QALY gained was 59 %. Base-case results indicated that improved overall response and PFS for OChl compared with chlorambucil translated to improved quality-adjusted life expectancy. Sensitivity analysis suggested that OChl is likely to be cost effective subject to uncertainty associated with the presence of any long-term OS benefit and the model time horizon.

Cost-Effectiveness of Treatment Sequences of Chemotherapies and Targeted Biologics for Elderly Metastatic Colorectal Cancer Patients.

PubMed

Parikh, Rohan C; Du, Xianglin L; Robert, Morgan O; Lairson, David R

2017-01-01

Treatment patterns for metastatic colorectal cancer (mCRC) patients have changed considerably over the last decade with the introduction of new chemotherapies and targeted biologics. These treatments are often administered in various sequences with limited evidence regarding their cost-effectiveness. To conduct a pharmacoeconomic evaluation of commonly administered treatment sequences among elderly mCRC patients. A probabilistic discrete event simulation model assuming Weibull distribution was developed to evaluate the cost-effectiveness of the following common treatment sequences: (a) first-line oxaliplatin/irinotecan followed by second-line oxaliplatin/irinotecan + bevacizumab (OI-OIB); (b) first-line oxaliplatin/irinotecan + bevacizumab followed by second-line oxaliplatin/irinotecan + bevacizumab (OIB-OIB); (c) OI-OIB followed by a third-line targeted biologic (OI-OIB-TB); and (d) OIB-OIB followed by a third-line targeted biologic (OIB-OIB-TB). Input parameters for the model were primarily obtained from the Surveillance, Epidemiology, and End Results-Medicare linked dataset for incident mCRC patients aged 65 years and older diagnosed from January 2004 through December 2009. A probabilistic sensitivity analysis was performed to account for parameter uncertainty. Costs (2014 U.S. dollars) and effectiveness were discounted at an annual rate of 3%. In the base case analyses, at the willingness-to-pay (WTP) threshold of $100,000/quality-adjusted life-year (QALY) gained, the treatment sequence OIB-OIB (vs. OI-OIB) was not cost-effective with an incremental cost-effectiveness ratio (ICER) per patient of $119,007/QALY; OI-OIB-TB (vs. OIB-OIB) was dominated; and OIB-OIB-TB (vs. OIB-OIB) was not cost-effective with an ICER of $405,857/QALY. Results similar to the base case analysis were obtained assuming log-normal distribution. Cost-effectiveness acceptability curves derived from a probabilistic sensitivity analysis showed that at a WTP of $100,000/QALY gained, sequence OI-OIB was 34% cost-effective, followed by OIB-OIB (31%), OI-OIB-TB (20%), and OIB-OIB-TB (15%). Overall, survival increases marginally with the addition of targeted biologics, such as bevacizumab, at first line and third line at substantial costs. Treatment sequences with bevacizumab at first line and targeted biologics at third line may not be cost-effective at the commonly used threshold of $100,000/QALY gained, but a marginal decrease in the cost of bevacizumab may make treatment sequences with first-line bevacizumab cost-effective. Future economic evaluations should validate the study results using parameters from ongoing clinical trials. This study was supported in part by a grant from the Agency for Healthcare Research and Quality (R01-HS018956) and in part by a grant from the Cancer Prevention and Research Institute of Texas (RP130051), which were obtained by Du. The authors report no conflicts of interest. Study concept and design were primarily contributed by Parikh, along with the other authors. All authors participated in data collection, and Parikh took the lead in data interpretation and analysis, along with Lairson and Morgan, with assistance from Du. The manuscript was written primarily by Parikh, along with Lairson, Morgan, and Du, and revised by Parikh.

Probabilistic structural analysis methods for space propulsion system components

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1986-01-01

The development of a three-dimensional inelastic analysis methodology for the Space Shuttle main engine (SSME) structural components is described. The methodology is composed of: (1) composite load spectra, (2) probabilistic structural analysis methods, (3) the probabilistic finite element theory, and (4) probabilistic structural analysis. The methodology has led to significant technical progress in several important aspects of probabilistic structural analysis. The program and accomplishments to date are summarized.

Potential Cost-Effectiveness of Universal Access to Modern Contraceptives in Uganda

PubMed Central

Babigumira, Joseph B.; Stergachis, Andy; Veenstra, David L.; Gardner, Jacqueline S.; Ngonzi, Joseph; Mukasa-Kivunike, Peter; Garrison, Louis P.

2012-01-01

Background Over two thirds of women who need contraception in Uganda lack access to modern effective methods. This study was conducted to estimate the potential cost-effectiveness of achieving universal access to modern contraceptives in Uganda by implementing a hypothetical new contraceptive program (NCP) from both societal and governmental (Ministry of Health (MoH)) perspectives. Methodology/Principal Findings A Markov model was developed to compare the NCP to the status quo or current contraceptive program (CCP). The model followed a hypothetical cohort of 15-year old girls over a lifetime horizon. Data were obtained from the Uganda National Demographic and Health Survey and from published and unpublished sources. Costs, life expectancy, disability-adjusted life expectancy, pregnancies, fertility and incremental cost-effectiveness measured as cost per life-year (LY) gained, cost per disability-adjusted life-year (DALY) averted, cost per pregnancy averted and cost per unit of fertility reduction were calculated. Univariate and probabilistic sensitivity analyses were performed to examine the robustness of results. Mean discounted life expectancy and disability-adjusted life expectancy (DALE) were higher under the NCP vs. CCP (28.74 vs. 28.65 years and 27.38 vs. 27.01 respectively). Mean pregnancies and live births per woman were lower under the NCP (9.51 vs. 7.90 and 6.92 vs. 5.79 respectively). Mean lifetime societal costs per woman were lower for the NCP from the societal perspective ($1,949 vs. $1,987) and the MoH perspective ($636 vs. $685). In the incremental analysis, the NCP dominated the CCP, i.e. it was both less costly and more effective. The results were robust to univariate and probabilistic sensitivity analysis. Conclusion/Significance Universal access to modern contraceptives in Uganda appears to be highly cost-effective. Increasing contraceptive coverage should be considered among Uganda's public health priorities. PMID:22363480

Cost-effectiveness of Stereotactic Body Radiation Therapy versus Radiofrequency Ablation for Hepatocellular Carcinoma: A Markov Modeling Study.

PubMed

Pollom, Erqi L; Lee, Kyueun; Durkee, Ben Y; Grade, Madeline; Mokhtari, Daniel A; Wahl, Daniel R; Feng, Mary; Kothary, Nishita; Koong, Albert C; Owens, Douglas K; Goldhaber-Fiebert, Jeremy; Chang, Daniel T

2017-05-01

Purpose To assess the cost-effectiveness of stereotactic body radiation therapy (SBRT) versus radiofrequency ablation (RFA) for patients with inoperable localized hepatocellular carcinoma (HCC) who are eligible for both SBRT and RFA. Materials and Methods A decision-analytic Markov model was developed for patients with inoperable, localized HCC who were eligible for both RFA and SBRT to evaluate the cost-effectiveness of the following treatment strategies: (a) SBRT as initial treatment followed by SBRT for local progression (SBRT-SBRT), (b) RFA followed by RFA for local progression (RFA-RFA), (c) SBRT followed by RFA for local progression (SBRT-RFA), and (d) RFA followed by SBRT for local progression (RFA-SBRT). Probabilities of disease progression, treatment characteristics, and mortality were derived from published studies. Outcomes included health benefits expressed as discounted quality-adjusted life years (QALYs), costs in U.S. dollars, and cost-effectiveness expressed as an incremental cost-effectiveness ratio. Deterministic and probabilistic sensitivity analysis was performed to assess the robustness of the findings. Results In the base case, SBRT-SBRT yielded the most QALYs (1.565) and cost $197 557. RFA-SBRT yielded 1.558 QALYs and cost $193 288. SBRT-SBRT was not cost-effective, at $558 679 per QALY gained relative to RFA-SBRT. RFA-SBRT was the preferred strategy, because RFA-RFA and SBRT-RFA were less effective and more costly. In all evaluated scenarios, SBRT was preferred as salvage therapy for local progression after RFA. Probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of $100 000 per QALY gained, RFA-SBRT was preferred in 65.8% of simulations. Conclusion SBRT for initial treatment of localized, inoperable HCC is not cost-effective. However, SBRT is the preferred salvage therapy for local progression after RFA. © RSNA, 2017 Online supplemental material is available for this article.

Cost-effectiveness of Stereotactic Body Radiation Therapy versus Radiofrequency Ablation for Hepatocellular Carcinoma: A Markov Modeling Study

PubMed Central

Lee, Kyueun; Durkee, Ben Y.; Grade, Madeline; Mokhtari, Daniel A.; Wahl, Daniel R.; Feng, Mary; Kothary, Nishita; Koong, Albert C.; Owens, Douglas K.; Goldhaber-Fiebert, Jeremy; Chang, Daniel T.

2017-01-01

Purpose To assess the cost-effectiveness of stereotactic body radiation therapy (SBRT) versus radiofrequency ablation (RFA) for patients with inoperable localized hepatocellular carcinoma (HCC) who are eligible for both SBRT and RFA. Materials and Methods A decision-analytic Markov model was developed for patients with inoperable, localized HCC who were eligible for both RFA and SBRT to evaluate the cost-effectiveness of the following treatment strategies: (a) SBRT as initial treatment followed by SBRT for local progression (SBRT-SBRT), (b) RFA followed by RFA for local progression (RFA-RFA), (c) SBRT followed by RFA for local progression (SBRT-RFA), and (d) RFA followed by SBRT for local progression (RFA-SBRT). Probabilities of disease progression, treatment characteristics, and mortality were derived from published studies. Outcomes included health benefits expressed as discounted quality-adjusted life years (QALYs), costs in U.S. dollars, and cost-effectiveness expressed as an incremental cost-effectiveness ratio. Deterministic and probabilistic sensitivity analysis was performed to assess the robustness of the findings. Results In the base case, SBRT-SBRT yielded the most QALYs (1.565) and cost $197 557. RFA-SBRT yielded 1.558 QALYs and cost $193 288. SBRT-SBRT was not cost-effective, at $558 679 per QALY gained relative to RFA-SBRT. RFA-SBRT was the preferred strategy, because RFA-RFA and SBRT-RFA were less effective and more costly. In all evaluated scenarios, SBRT was preferred as salvage therapy for local progression after RFA. Probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of $100 000 per QALY gained, RFA-SBRT was preferred in 65.8% of simulations. Conclusion SBRT for initial treatment of localized, inoperable HCC is not cost-effective. However, SBRT is the preferred salvage therapy for local progression after RFA. © RSNA, 2017 Online supplemental material is available for this article. PMID:28045603

Cost Effectiveness of Alectinib vs. Crizotinib in First-Line Anaplastic Lymphoma Kinase-Positive Advanced Non-Small-Cell Lung Cancer.

PubMed

Carlson, Josh J; Suh, Kangho; Orfanos, Panos; Wong, William

2018-04-01

The recently completed ALEX trial demonstrated that alectinib improved progression-free survival, and delayed time to central nervous system progression compared with crizotinib in patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer. However, the long-term clinical and economic impact of using alectinib vs. crizotinib has not been evaluated. The objective of this study was to determine the potential cost utility of alectinib vs. crizotinib from a US payer perspective. A cost-utility model was developed using partition survival methods and three health states: progression-free, post-progression, and death. ALEX trial data informed the progression-free and overall survival estimates. Costs included drug treatments and supportive care (central nervous system and non-central nervous system). Utility values were obtained from trial data and literature. Sensitivity analyses included one-way and probabilistic sensitivity analyses. Treatment with alectinib vs. crizotinib resulted in a gain of 0.91 life-years, 0.87 quality-adjusted life-years, and incremental costs of US$34,151, resulting in an incremental cost-effectiveness ratio of US$39,312/quality-adjusted life-year. Drug costs and utilities in the progression-free health state were the main drivers of the model in the one-way sensitivity analysis. From the probabilistic sensitivity analysis, alectinib had a 64% probability of being cost effective at a willingness-to-pay threshold of US$100,000/quality adjusted life-year. Alectinib increased time in the progression-free state and quality-adjusted life-years vs. crizotinib. The marginal cost increase was reflective of longer treatment durations in the progression-free state. Central nervous system-related costs were considerably lower with alectinib. Our results suggest that compared with crizotinib, alectinib may be a cost-effective therapy for treatment-naïve patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer.

Cost-effectiveness of linaclotide compared to antidepressants in the treatment of irritable bowel syndrome with constipation in Scotland.

PubMed

Fisher, Mark; Walker, Andrew; Falqués, Meritxell; Moya, Miguel; Rance, Mark; Taylor, Douglas; Lindner, Leandro

2016-12-01

Presently, linaclotide is the only EMA-approved therapy indicated for the treatment of irritable bowel syndrome with constipation (IBS-C). This study sought to determine the cost-effectiveness of linaclotide compared to antidepressants for the treatment of adults with moderate to severe IBS-C who have previously received antispasmodics and/or laxatives. A Markov model was created to estimate costs and QALYs over a 5-year time horizon from the perspective of NHS Scotland. Health states were based on treatment satisfaction (satisfied, moderately satisfied, not satisfied) and mortality. Transition probabilities were based on satisfaction data from the linaclotide pivotal studies and Scottish general all-cause mortality statistics. Treatment costs were calculated from the British National Formulary. NHS resource use and disease-related costs for each health state were estimated from Scottish clinician interviews in combination with NHS Reference costs. Quality of life was based on EQ-5D data collected from the pivotal studies. Costs and QALYs were discounted at 3.5 % per annum. Uncertainty was explored through extensive deterministic and probabilistic sensitivity analyses. Over a 5-year time horizon, the additional costs and QALYs generated with linaclotide were £659 and 0.089, resulting in an incremental cost-effectiveness ratio of £7370 per QALY versus antidepressants. Based on the probabilistic sensitivity analysis, the likelihood that linaclotide was cost-effective at a willingness to pay of £20,000 per QALY was 73 %. Linaclotide can be a cost-effective treatment for adults with moderate-to-severe IBS-C who have previously received antispasmodics and/or laxatives in Scotland.

Pipeline embolization device versus coiling for the treatment of large and giant unruptured intracranial aneurysms: a cost-effectiveness analysis.

PubMed

Wali, Arvin R; Park, Charlie C; Santiago-Dieppa, David R; Vaida, Florin; Murphy, James D; Khalessi, Alexander A

2017-06-01

OBJECTIVE Rupture of large or giant intracranial aneurysms leads to significant morbidity, mortality, and health care costs. Both coiling and the Pipeline embolization device (PED) have been shown to be safe and clinically effective for the treatment of unruptured large and giant intracranial aneurysms; however, the relative cost-to-outcome ratio is unknown. The authors present the first cost-effectiveness analysis to compare the economic impact of the PED compared with coiling or no treatment for the endovascular management of large or giant intracranial aneurysms. METHODS A Markov model was constructed to simulate a 60-year-old woman with a large or giant intracranial aneurysm considering a PED, endovascular coiling, or no treatment in terms of neurological outcome, angiographic outcome, retreatment rates, procedural and rehabilitation costs, and rupture rates. Transition probabilities were derived from prior literature reporting outcomes and costs of PED, coiling, and no treatment for the management of aneurysms. Cost-effectiveness was defined, with the incremental cost-effectiveness ratios (ICERs) defined as difference in costs divided by the difference in quality-adjusted life years (QALYs). The ICERs < $50,000/QALY gained were considered cost-effective. To study parameter uncertainty, 1-way, 2-way, and probabilistic sensitivity analyses were performed. RESULTS The base-case model demonstrated lifetime QALYs of 12.72 for patients in the PED cohort, 12.89 for the endovascular coiling cohort, and 9.7 for patients in the no-treatment cohort. Lifetime rehabilitation and treatment costs were $59,837.52 for PED; $79,025.42 for endovascular coiling; and $193,531.29 in the no-treatment cohort. Patients who did not undergo elective treatment were subject to increased rates of aneurysm rupture and high treatment and rehabilitation costs. One-way sensitivity analysis demonstrated that the model was most sensitive to assumptions about the costs and mortality risks for PED and coiling. Probabilistic sampling demonstrated that PED was the cost-effective strategy in 58.4% of iterations, coiling was the cost-effective strategy in 41.4% of iterations, and the no-treatment option was the cost-effective strategy in only 0.2% of iterations. CONCLUSIONS The authors' cost-effective model demonstrated that elective endovascular techniques such as PED and endovascular coiling are cost-effective strategies for improving health outcomes and lifetime quality of life measures in patients with large or giant unruptured intracranial aneurysm.

Routine magnetic resonance imaging for idiopathic olfactory loss: a modeling-based economic evaluation.

PubMed

Rudmik, Luke; Smith, Kristine A; Soler, Zachary M; Schlosser, Rodney J; Smith, Timothy L

2014-10-01

Idiopathic olfactory loss is a common clinical scenario encountered by otolaryngologists. While trying to allocate limited health care resources appropriately, the decision to obtain a magnetic resonance imaging (MRI) scan to investigate for a rare intracranial abnormality can be difficult. To evaluate the cost-effectiveness of ordering routine MRI in patients with idiopathic olfactory loss. We performed a modeling-based economic evaluation with a time horizon of less than 1 year. Patients included in the analysis had idiopathic olfactory loss defined by no preceding viral illness or head trauma and negative findings of a physical examination and nasal endoscopy. Routine MRI vs no-imaging strategies. We developed a decision tree economic model from the societal perspective. Effectiveness, probability, and cost data were obtained from the published literature. Litigation rates and costs related to a missed diagnosis were obtained from the Physicians Insurers Association of America. A univariate threshold analysis and multivariate probabilistic sensitivity analysis were performed to quantify the degree of certainty in the economic conclusion of the reference case. The comparative groups included those who underwent routine MRI of the brain with contrast alone and those who underwent no brain imaging. The primary outcome was the cost per correct diagnosis of idiopathic olfactory loss. The mean (SD) cost for the MRI strategy totaled $2400.00 ($1717.54) and was effective 100% of the time, whereas the mean (SD) cost for the no-imaging strategy totaled $86.61 ($107.40) and was effective 98% of the time. The incremental cost-effectiveness ratio for the MRI strategy compared with the no-imaging strategy was $115 669.50, which is higher than most acceptable willingness-to-pay thresholds. The threshold analysis demonstrated that when the probability of having a treatable intracranial disease process reached 7.9%, the incremental cost-effectiveness ratio for MRI vs no imaging was $24 654.38. The probabilistic sensitivity analysis demonstrated that the no-imaging strategy was the cost-effective decision with 81% certainty at a willingness-to-pay threshold of $50 000. This economic evaluation suggests that the most cost-effective decision is to not obtain a routine MRI scan of the brain in patients with idiopathic olfactory loss. Outcomes from this study may be used to counsel patients and aid in the decision-making process.

Cost-effectiveness of continuation maintenance pemetrexed after cisplatin and pemetrexed chemotherapy for advanced nonsquamous non-small-cell lung cancer: estimates from the perspective of the Chinese health care system.

PubMed

Zeng, Xiaohui; Peng, Liubao; Li, Jianhe; Chen, Gannong; Tan, Chongqing; Wang, Siying; Wan, Xiaomin; Ouyang, Lihui; Zhao, Ziying

2013-01-01

Continuation maintenance treatment with pemetrexed is approved by current clinical guidelines as a category 2A recommendation after induction therapy with cisplatin and pemetrexed chemotherapy (CP strategy) for patients with advanced nonsquamous non-small-cell lung cancer (NSCLC). However, the cost-effectiveness of the treatment remains unclear. We completed a trial-based assessment, from the perspective of the Chinese health care system, of the cost-effectiveness of maintenance pemetrexed treatment after a CP strategy for patients with advanced nonsquamous NSCLC. A Markov model was developed to estimate costs and benefits. It was based on a clinical trial that compared continuation maintenance pemetrexed therapy plus best supportive care (BSC) versus placebo plus BSC after a CP strategy for advanced nonsquamous NSCLC. Sensitivity analyses were conducted to assess the stability of the model. The model base case analysis suggested that continuation maintenance pemetrexed therapy after a CP strategy would increase benefits in a 1-, 2-, 5-, or 10-year time horizon, with incremental costs of $183,589.06, $126,353.16, $124,766.68, and $124,793.12 per quality-adjusted life-year gained, respectively. The most sensitive influential variable in the cost-effectiveness analysis was the utility of the progression-free survival state, followed by proportion of patients with postdiscontinuation therapy in both arms, proportion of BSC costs for PFS versus progressed survival state, and cost of pemetrexed. Probabilistic sensitivity analysis indicated that the cost-effective probability of adding continuation maintenance pemetrexed therapy to BSC was zero. One-way and probabilistic sensitivity analyses revealed that the Markov model was robust. Continuation maintenance of pemetrexed after a CP strategy for patients with advanced nonsquamous NSCLC is not cost-effective based on a recent clinical trial. Decreasing the price or adjusting the dosage of pemetrexed may be a better option for meeting the treatment demands of Chinese patients. Copyright © 2013 Elsevier HS Journals, Inc. All rights reserved.

Geothermal probabilistic cost study

NASA Technical Reports Server (NTRS)

Orren, L. H.; Ziman, G. M.; Jones, S. C.; Lee, T. K.; Noll, R.; Wilde, L.; Sadanand, V.

1981-01-01

A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model was used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents was analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance were examined.

Modeling the economic impact of linezolid versus vancomycin in confirmed nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus.

PubMed

Patel, Dipen A; Shorr, Andrew F; Chastre, Jean; Niederman, Michael; Simor, Andrew; Stephens, Jennifer M; Charbonneau, Claudie; Gao, Xin; Nathwani, Dilip

2014-07-22

We compared the economic impacts of linezolid and vancomycin for the treatment of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA)-confirmed nosocomial pneumonia. We used a 4-week decision tree model incorporating published data and expert opinion on clinical parameters, resource use and costs (in 2012 US dollars), such as efficacy, mortality, serious adverse events, treatment duration and length of hospital stay. The results presented are from a US payer perspective. The base case first-line treatment duration for patients with MRSA-confirmed nosocomial pneumonia was 10 days. Clinical treatment success (used for the cost-effectiveness ratio) and failure due to lack of efficacy, serious adverse events or mortality were possible clinical outcomes that could impact costs. Cost of treatment and incremental cost-effectiveness per successfully treated patient were calculated for linezolid versus vancomycin. Univariate (one-way) and probabilistic sensitivity analyses were conducted. The model allowed us to calculate the total base case inpatient costs as $46,168 (linezolid) and $46,992 (vancomycin). The incremental cost-effectiveness ratio favored linezolid (versus vancomycin), with lower costs ($824 less) and greater efficacy (+2.7% absolute difference in the proportion of patients successfully treated for MRSA nosocomial pneumonia). Approximately 80% of the total treatment costs were attributed to hospital stay (primarily in the intensive care unit). The results of our probabilistic sensitivity analysis indicated that linezolid is the cost-effective alternative under varying willingness to pay thresholds. These model results show that linezolid has a favorable incremental cost-effectiveness ratio compared to vancomycin for MRSA-confirmed nosocomial pneumonia, largely attributable to the higher clinical trial response rate of patients treated with linezolid. The higher drug acquisition cost of linezolid was offset by lower treatment failure-related costs and fewer days of hospitalization.

An Assessment of the Effectiveness of Air Force Risk Management Practices in Program Acquisition Using Survey Instrument Analysis

DTIC Science & Technology

2015-06-18

Engineering Effectiveness Survey. CMU/SEI-2012-SR-009. Carnegie Mellon University. November 2012. Field, Andy. Discovering Statistics Using SPSS , 3rd...enough into the survey to begin answering questions on risk practices. All of the data statistical analysis will be performed using SPSS . Prior to...probabilistically using distributions for likelihood and impact. Statistical methods like Monte Carlo can more comprehensively evaluate the cost and

Probabilistic risk analysis and terrorism risk.

PubMed

Ezell, Barry Charles; Bennett, Steven P; von Winterfeldt, Detlof; Sokolowski, John; Collins, Andrew J

2010-04-01

Since the terrorist attacks of September 11, 2001, and the subsequent establishment of the U.S. Department of Homeland Security (DHS), considerable efforts have been made to estimate the risks of terrorism and the cost effectiveness of security policies to reduce these risks. DHS, industry, and the academic risk analysis communities have all invested heavily in the development of tools and approaches that can assist decisionmakers in effectively allocating limited resources across the vast array of potential investments that could mitigate risks from terrorism and other threats to the homeland. Decisionmakers demand models, analyses, and decision support that are useful for this task and based on the state of the art. Since terrorism risk analysis is new, no single method is likely to meet this challenge. In this article we explore a number of existing and potential approaches for terrorism risk analysis, focusing particularly on recent discussions regarding the applicability of probabilistic and decision analytic approaches to bioterrorism risks and the Bioterrorism Risk Assessment methodology used by the DHS and criticized by the National Academies and others.

Sensitivity Analysis in Sequential Decision Models.

PubMed

Chen, Qiushi; Ayer, Turgay; Chhatwal, Jagpreet

2017-02-01

Sequential decision problems are frequently encountered in medical decision making, which are commonly solved using Markov decision processes (MDPs). Modeling guidelines recommend conducting sensitivity analyses in decision-analytic models to assess the robustness of the model results against the uncertainty in model parameters. However, standard methods of conducting sensitivity analyses cannot be directly applied to sequential decision problems because this would require evaluating all possible decision sequences, typically in the order of trillions, which is not practically feasible. As a result, most MDP-based modeling studies do not examine confidence in their recommended policies. In this study, we provide an approach to estimate uncertainty and confidence in the results of sequential decision models. First, we provide a probabilistic univariate method to identify the most sensitive parameters in MDPs. Second, we present a probabilistic multivariate approach to estimate the overall confidence in the recommended optimal policy considering joint uncertainty in the model parameters. We provide a graphical representation, which we call a policy acceptability curve, to summarize the confidence in the optimal policy by incorporating stakeholders' willingness to accept the base case policy. For a cost-effectiveness analysis, we provide an approach to construct a cost-effectiveness acceptability frontier, which shows the most cost-effective policy as well as the confidence in that for a given willingness to pay threshold. We demonstrate our approach using a simple MDP case study. We developed a method to conduct sensitivity analysis in sequential decision models, which could increase the credibility of these models among stakeholders.

Trastuzumab in early stage breast cancer: a cost-effectiveness analysis for Belgium.

PubMed

Neyt, Mattias; Huybrechts, Michel; Hulstaert, Frank; Vrijens, France; Ramaekers, Dirk

2008-08-01

Although trastuzumab is traditionally used in metastatic breast cancer treatment, studies reported on the efficacy and safety of trastuzumab in adjuvant setting for the treatment of early stage breast cancer in HER2+ tumors. We estimated the cost-effectiveness and budget impact of reimbursing trastuzumab in this indication from a payer's perspective. We constructed a health economic model. Long-term consequences of preventing patients to progress to metastatic breast cancer and side effects such as congestive heart failure were taken into account. Uncertainty was handled applying probabilistic modeling and through probabilistic sensitivity analyses. In the HERA scenario, applying an arbitrary threshold of euro30000 per life-year gained, early stage breast cancer treatment with trastuzumab is cost-effective for 9 out of 15 analyzed subgroups (according to age and stage). In contrast, treatment according to the FinHer scenario is cost-effective in 14 subgroups. Furthermore, the FinHer regimen is most of the times cost saving with an average incremental cost of euro668, euro-1045, and euro-6869 for respectively stages I, II and III breast cancer patients whereas the HERA regimen is never cost saving due to the higher initial treatment costs. The model shows better cost-effectiveness for the 9-week initial treatment (FinHer) compared to no trastuzumab treatment than for the 1-year post-chemotherapy treatment (HERA). Both from a medical and an economic point of view, the 9-week initial treatment regimen with trastuzumab shows promising results and justifies the initiation of a large comparative trial with a 1-year regimen.

Is probabilistic bias analysis approximately Bayesian?

PubMed Central

MacLehose, Richard F.; Gustafson, Paul

2011-01-01

Case-control studies are particularly susceptible to differential exposure misclassification when exposure status is determined following incident case status. Probabilistic bias analysis methods have been developed as ways to adjust standard effect estimates based on the sensitivity and specificity of exposure misclassification. The iterative sampling method advocated in probabilistic bias analysis bears a distinct resemblance to a Bayesian adjustment; however, it is not identical. Furthermore, without a formal theoretical framework (Bayesian or frequentist), the results of a probabilistic bias analysis remain somewhat difficult to interpret. We describe, both theoretically and empirically, the extent to which probabilistic bias analysis can be viewed as approximately Bayesian. While the differences between probabilistic bias analysis and Bayesian approaches to misclassification can be substantial, these situations often involve unrealistic prior specifications and are relatively easy to detect. Outside of these special cases, probabilistic bias analysis and Bayesian approaches to exposure misclassification in case-control studies appear to perform equally well. PMID:22157311

Cost-effectiveness of pazopanib compared with sunitinib in metastatic renal cell carcinoma in Canada

PubMed Central

Amdahl, J.; Diaz, J.; Park, J.; Nakhaipour, H.R.; Delea, T.E.

2016-01-01

Background In Canada and elsewhere, pazopanib and sunitinib—tyrosine kinase inhibitors targeting the vascular endothelial growth factor receptors—are recommended as first-line treatment for patients with metastatic renal cell carcinoma (mrcc). A large randomized noninferiority trial of pazopanib versus sunitinib (comparz) demonstrated that the two drugs have similar efficacy; however, patients randomized to pazopanib experienced better health-related quality of life (hrqol) and nominally lower rates of non-study medical resource utilization. Methods The cost-effectiveness of pazopanib compared with sunitinib for first-line treatment of mrcc from a Canadian health care system perspective was evaluated using a partitioned-survival model that incorporated data from comparz and other secondary sources. The time horizon of 5 years was based on the maximum duration of follow-up in the final analysis of overall survival from the comparz trial. Analyses were conducted first using list prices for pazopanib and sunitinib and then by assuming that the prices of sunitinib and pazopanib would be equivalent. Results Based on list prices, expected costs were CA$10,293 less with pazopanib than with sunitinib. Pazopanib was estimated to yield 0.059 more quality-adjusted life-years (qalys). Pazopanib was therefore dominant (more qalys and lower costs) compared with sunitinib in the base case. In probabilistic sensitivity analyses, pazopanib was dominant in 79% of simulations and was cost-effective in 90%–100% of simulations at a threshold cost-effectiveness ratio of CA$100,000. Assuming equivalent pricing, pazopanib yielded CA$917 in savings in the base case, was dominant in 36% of probabilistic sensitivity analysis simulations, and was cost-effective in 89% of simulations at a threshold cost-effectiveness ratio of CA$100,000. Conclusions Compared with sunitinib, pazopanib is likely to be a cost-effective option for first-line treatment of mrcc from a Canadian health care perspective. PMID:27536183

Probabilistic Multi-Scale, Multi-Level, Multi-Disciplinary Analysis and Optimization of Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2000-01-01

Aircraft engines are assemblies of dynamically interacting components. Engine updates to keep present aircraft flying safely and engines for new aircraft are progressively required to operate in more demanding technological and environmental requirements. Designs to effectively meet those requirements are necessarily collections of multi-scale, multi-level, multi-disciplinary analysis and optimization methods and probabilistic methods are necessary to quantify respective uncertainties. These types of methods are the only ones that can formally evaluate advanced composite designs which satisfy those progressively demanding requirements while assuring minimum cost, maximum reliability and maximum durability. Recent research activities at NASA Glenn Research Center have focused on developing multi-scale, multi-level, multidisciplinary analysis and optimization methods. Multi-scale refers to formal methods which describe complex material behavior metal or composite; multi-level refers to integration of participating disciplines to describe a structural response at the scale of interest; multidisciplinary refers to open-ended for various existing and yet to be developed discipline constructs required to formally predict/describe a structural response in engine operating environments. For example, these include but are not limited to: multi-factor models for material behavior, multi-scale composite mechanics, general purpose structural analysis, progressive structural fracture for evaluating durability and integrity, noise and acoustic fatigue, emission requirements, hot fluid mechanics, heat-transfer and probabilistic simulations. Many of these, as well as others, are encompassed in an integrated computer code identified as Engine Structures Technology Benefits Estimator (EST/BEST) or Multi-faceted/Engine Structures Optimization (MP/ESTOP). The discipline modules integrated in MP/ESTOP include: engine cycle (thermodynamics), engine weights, internal fluid mechanics, cost, mission and coupled structural/thermal, various composite property simulators and probabilistic methods to evaluate uncertainty effects (scatter ranges) in all the design parameters. The objective of the proposed paper is to briefly describe a multi-faceted design analysis and optimization capability for coupled multi-discipline engine structures optimization. Results are presented for engine and aircraft type metrics to illustrate the versatility of that capability. Results are also presented for reliability, noise and fatigue to illustrate its inclusiveness. For example, replacing metal rotors with composites reduces the engine weight by 20 percent, 15 percent noise reduction, and an order of magnitude improvement in reliability. Composite designs exist to increase fatigue life by at least two orders of magnitude compared to state-of-the-art metals.

A lifetime Markov model for the economic evaluation of chronic obstructive pulmonary disease.

PubMed

Menn, Petra; Leidl, Reiner; Holle, Rolf

2012-09-01

Chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of death worldwide. It has serious health effects and causes substantial costs for society. The aim of the present paper was to develop a state-of-the-art decision-analytic model of COPD whereby the cost effectiveness of interventions in Germany can be estimated. To demonstrate the applicability of the model, a smoking cessation programme was evaluated against usual care. A seven-stage Markov model (disease stages I to IV according to the GOLD [Global Initiative for Chronic Obstructive Lung Disease] classification, states after lung-volume reduction surgery and lung transplantation, death) was developed to conduct a cost-utility analysis from the societal perspective over a time horizon of 10, 40 and 60 years. Patients entered the cohort model at the age of 45 with mild COPD. Exacerbations were classified into three levels: mild, moderate and severe. Estimation of stage-specific probabilities (for smokers and quitters), utilities and costs was based on German data where possible. Data on effectiveness of the intervention was retrieved from the literature. A discount rate of 3% was applied to costs and effects. Probabilistic sensitivity analysis was used to assess the robustness of the results. The smoking cessation programme was the dominant strategy compared with usual care, and the intervention resulted in an increase in health effects of 0.54 QALYs and a cost reduction of &U20AC;1115 per patient (year 2007 prices) after 60 years. In the probabilistic analysis, the intervention dominated in about 95% of the simulations. Sensitivity analyses showed that uncertainty primarily originated from data on disease progression and treatment cost in the early stages of disease. The model developed allows the long-term cost effectiveness of interventions to be estimated, and has been adapted to Germany. The model suggests that the smoking cessation programme evaluated was more effective than usual care as well as being cost-saving. Most patients had mild or moderate COPD, stages for which parameter uncertainty was found to be high. This raises the need to improve data on the early stages of COPD.

Economic outcomes of maintenance gefitinib for locally advanced/metastatic non-small-cell lung cancer with unknown EGFR mutations: a semi-Markov model analysis.

PubMed

Zeng, Xiaohui; Li, Jianhe; Peng, Liubao; Wang, Yunhua; Tan, Chongqing; Chen, Gannong; Wan, Xiaomin; Lu, Qiong; Yi, Lidan

2014-01-01

Maintenance gefitinib significantly prolonged progression-free survival (PFS) compared with placebo in patients from eastern Asian with locally advanced/metastatic non-small-cell lung cancer (NSCLC) after four chemotherapeutic cycles (21 days per cycle) of first-line platinum-based combination chemotherapy without disease progression. The objective of the current study was to evaluate the cost-effectiveness of maintenance gefitinib therapy after four chemotherapeutic cycle's stand first-line platinum-based chemotherapy for patients with locally advanced or metastatic NSCLC with unknown EGFR mutations, from a Chinese health care system perspective. A semi-Markov model was designed to evaluate cost-effectiveness of the maintenance gefitinib treatment. Two-parametric Weibull and Log-logistic distribution were fitted to PFS and overall survival curves independently. One-way and probabilistic sensitivity analyses were conducted to assess the stability of the model designed. The model base-case analysis suggested that maintenance gefitinib would increase benefits in a 1, 3, 6 or 10-year time horizon, with incremental $184,829, $19,214, $19,328, and $21,308 per quality-adjusted life-year (QALY) gained, respectively. The most sensitive influential variable in the cost-effectiveness analysis was utility of PFS plus rash, followed by utility of PFS plus diarrhoea, utility of progressed disease, price of gefitinib, cost of follow-up treatment in progressed survival state, and utility of PFS on oral therapy. The price of gefitinib is the most significant parameter that could reduce the incremental cost per QALY. Probabilistic sensitivity analysis indicated that the cost-effective probability of maintenance gefitinib was zero under the willingness-to-pay (WTP) threshold of $16,349 (3 × per-capita gross domestic product of China). The sensitivity analyses all suggested that the model was robust. Maintenance gefitinib following first-line platinum-based chemotherapy for patients with locally advanced/metastatic NSCLC with unknown EGFR mutations is not cost-effective. Decreasing the price of gefitinib may be a preferential choice for meeting widely treatment demands in China.

Health economics of targeted intraoperative radiotherapy (TARGIT-IORT) for early breast cancer: a cost-effectiveness analysis in the United Kingdom.

PubMed

Vaidya, Anil; Vaidya, Param; Both, Brigitte; Brew-Graves, Chris; Bulsara, Max; Vaidya, Jayant S

2017-08-17

The clinical effectiveness of targeted intraoperative radiotherapy (TARGIT-IORT) has been confirmed in the randomised TARGIT-A (targeted intraoperative radiotherapy-alone) trial to be similar to a several weeks' course of whole-breast external-beam radiation therapy (EBRT) in patients with early breast cancer. This study aims to determine the cost-effectiveness of TARGIT-IORT to inform policy decisions about its wider implementation. TARGIT-A randomised clinical trial (ISRCTN34086741) which compared TARGIT with traditional EBRT and found similar breast cancer control, particularly when TARGIT was given simultaneously with lumpectomy. Cost-utility analysis using decision analytic modelling by a Markov model. A cost-effectiveness Markov model was developed using TreeAge Pro V.2015. The decision analytic model compared two strategies of radiotherapy for breast cancer in a hypothetical cohort of patients with early breast cancer based on the published health state transition probability data from the TARGIT-A trial. Analysis was performed for UK setting and National Health Service (NHS) healthcare payer's perspective using NHS cost data and treatment outcomes were simulated for both strategies for a time horizon of 10 years. Model health state utilities were drawn from the published literature. Future costs and effects were discounted at the rate of 3.5%. To address uncertainty, one-way and probabilistic sensitivity analyses were performed. Quality-adjusted life-years (QALYs). In the base case analysis, TARGIT-IORT was a highly cost-effective strategy yielding health gain at a lower cost than its comparator EBRT. Discounted TARGIT-IORT and EBRT costs for the time horizon of 10 years were £12 455 and £13 280, respectively. TARGIT-IORT gained 0.18 incremental QALY as the discounted QALYs gained by TARGIT-IORT were 8.15 and by EBRT were 7.97 showing TARGIT-IORT as a dominant strategy over EBRT. Model outputs were robust to one-way and probabilistic sensitivity analyses. TARGIT-IORT is a dominant strategy over EBRT, being less costly and producing higher QALY gain. ISRCTN34086741; post results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Using Probabilistic Terrorism Risk Modeling for Regulatory Benefit-Cost Analysis. Application to the Western Hemisphere Travel Initiative Implemented in the Land Environment

DTIC Science & Technology

2007-05-01

Dixon and Stern, 2004), and gun violence prevention programs ( Tita et al., 2003). As DHS considers promulgating regulations and implementing new...communication 2/21/07. Tita , G., K. J. Riley, G. Ridgeway, C. A. Grammich, A. Abrahamse, and P. W. Greenwood (2003), Reducing Gun Violence: Results

Cost-effectiveness of two versus three or more doses of intermittent preventive treatment for malaria during pregnancy in sub-Saharan Africa: a modelling study of meta-analysis and cost data.

PubMed

Fernandes, Silke; Sicuri, Elisa; Kayentao, Kassoum; van Eijk, Anne Maria; Hill, Jenny; Webster, Jayne; Were, Vincent; Akazili, James; Madanitsa, Mwayi; ter Kuile, Feiko O; Hanson, Kara

2015-03-01

In 2012, WHO changed its recommendation for intermittent preventive treatment of malaria during pregnancy (IPTp) from two doses to monthly doses of sulfadoxine-pyrimethamine during the second and third trimesters, but noted the importance of a cost-effectiveness analysis to lend support to the decision of policy makers. We therefore estimated the incremental cost-effectiveness of IPTp with three or more (IPTp-SP3+) versus two doses of sulfadoxine-pyrimethamine (IPTp-SP2). For this analysis, we used data from a 2013 meta-analysis of seven studies in sub-Saharan Africa. We developed a decision tree model with a lifetime horizon. We analysed the base case from a societal perspective. We did deterministic and probabilistic sensitivity analyses with appropriate parameter ranges and distributions for settings with low, moderate, and high background risk of low birthweight, and did a separate analysis for HIV-negative women. Parameters in the model were obtained for all countries included in the original meta-analysis. We did simulations in hypothetical cohorts of 1000 pregnant women receiving either IPTp-SP3+ or IPTp-SP2. We calculated disability-adjusted life-years (DALYs) for low birthweight, severe to moderate anaemia, and clinical malaria. We calculated cost estimates from data obtained in observational studies, exit surveys, and from public procurement databases. We give financial and economic costs in constant 2012 US$. The main outcome measure was the incremental cost per DALY averted. The delivery of IPTp-SP3+ to 1000 pregnant women averted 113·4 DALYs at an incremental cost of $825·67 producing an incremental cost-effectiveness ratio (ICER) of $7·28 per DALY averted. The results remained robust in the deterministic sensitivity analysis. In the probabilistic sensitivity analyses, the ICER was $7·7 per DALY averted for moderate risk of low birthweight, $19·4 per DALY averted for low risk, and $4·0 per DALY averted for high risk. The ICER for HIV-negative women was $6·2 per DALY averted. Our findings lend strong support to the WHO guidelines that recommend a monthly dose of IPTp-SP from the second trimester onwards. Malaria in Pregnancy Consortium and the Bill & Melinda Gates Foundation. Copyright © 2015 Fernandes et al. Open Access article distributed under the terms of CC BY-NC-SA. Published by .. All rights reserved.

Using probabilistic theory to develop interpretation guidelines for Y-STR profiles.

PubMed

Taylor, Duncan; Bright, Jo-Anne; Buckleton, John

2016-03-01

Y-STR profiling makes up a small but important proportion of forensic DNA casework. Often Y-STR profiles are used when autosomal profiling has failed to yield an informative result. Consequently Y-STR profiles are often from the most challenging samples. In addition to these points, Y-STR loci are linked, meaning that evaluation of haplotype probabilities are either based on overly simplified counting methods or computationally costly genetic models, neither of which extend well to the evaluation of mixed Y-STR data. For all of these reasons Y-STR data analysis has not seen the same advances as autosomal STR data. We present here a probabilistic model for the interpretation of Y-STR data. Due to the fact that probabilistic systems for Y-STR data are still some way from reaching active casework, we also describe how data can be analysed in a continuous way to generate interpretational thresholds and guidelines. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Probabilistic modeling of anatomical variability using a low dimensional parameterization of diffeomorphisms.

PubMed

Zhang, Miaomiao; Wells, William M; Golland, Polina

2017-10-01

We present an efficient probabilistic model of anatomical variability in a linear space of initial velocities of diffeomorphic transformations and demonstrate its benefits in clinical studies of brain anatomy. To overcome the computational challenges of the high dimensional deformation-based descriptors, we develop a latent variable model for principal geodesic analysis (PGA) based on a low dimensional shape descriptor that effectively captures the intrinsic variability in a population. We define a novel shape prior that explicitly represents principal modes as a multivariate complex Gaussian distribution on the initial velocities in a bandlimited space. We demonstrate the performance of our model on a set of 3D brain MRI scans from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Our model yields a more compact representation of group variation at substantially lower computational cost than the state-of-the-art method such as tangent space PCA (TPCA) and probabilistic principal geodesic analysis (PPGA) that operate in the high dimensional image space. Copyright © 2017 Elsevier B.V. All rights reserved.

Probabilistic structural analysis methods for select space propulsion system components

NASA Technical Reports Server (NTRS)

Millwater, H. R.; Cruse, T. A.

1989-01-01

The Probabilistic Structural Analysis Methods (PSAM) project developed at the Southwest Research Institute integrates state-of-the-art structural analysis techniques with probability theory for the design and analysis of complex large-scale engineering structures. An advanced efficient software system (NESSUS) capable of performing complex probabilistic analysis has been developed. NESSUS contains a number of software components to perform probabilistic analysis of structures. These components include: an expert system, a probabilistic finite element code, a probabilistic boundary element code and a fast probability integrator. The NESSUS software system is shown. An expert system is included to capture and utilize PSAM knowledge and experience. NESSUS/EXPERT is an interactive menu-driven expert system that provides information to assist in the use of the probabilistic finite element code NESSUS/FEM and the fast probability integrator (FPI). The expert system menu structure is summarized. The NESSUS system contains a state-of-the-art nonlinear probabilistic finite element code, NESSUS/FEM, to determine the structural response and sensitivities. A broad range of analysis capabilities and an extensive element library is present.

Economic evaluation of DNA ploidy analysis vs liquid-based cytology for cervical screening.

PubMed

Nghiem, V T; Davies, K R; Beck, J R; Follen, M; MacAulay, C; Guillaud, M; Cantor, S B

2015-06-09

DNA ploidy analysis involves automated quantification of chromosomal aneuploidy, a potential marker of progression toward cervical carcinoma. We evaluated the cost-effectiveness of this method for cervical screening, comparing five ploidy strategies (using different numbers of aneuploid cells as cut points) with liquid-based Papanicolaou smear and no screening. A state-transition Markov model simulated the natural history of HPV infection and possible progression into cervical neoplasia in a cohort of 12-year-old females. The analysis evaluated cost in 2012 US$ and effectiveness in quality-adjusted life-years (QALYs) from a health-system perspective throughout a lifetime horizon in the US setting. We calculated incremental cost-effectiveness ratios (ICERs) to determine the best strategy. The robustness of optimal choices was examined in deterministic and probabilistic sensitivity analyses. In the base-case analysis, the ploidy 4 cell strategy was cost-effective, yielding an increase of 0.032 QALY and an ICER of $18 264/QALY compared to no screening. For most scenarios in the deterministic sensitivity analysis, the ploidy 4 cell strategy was the only cost-effective strategy. Cost-effectiveness acceptability curves showed that this strategy was more likely to be cost-effective than the Papanicolaou smear. Compared to the liquid-based Papanicolaou smear, screening with a DNA ploidy strategy appeared less costly and comparably effective.

The cost-effectiveness of screening for colorectal cancer.

PubMed

Telford, Jennifer J; Levy, Adrian R; Sambrook, Jennifer C; Zou, Denise; Enns, Robert A

2010-09-07

Published decision analyses show that screening for colorectal cancer is cost-effective. However, because of the number of tests available, the optimal screening strategy in Canada is unknown. We estimated the incremental cost-effectiveness of 10 strategies for colorectal cancer screening, as well as no screening, incorporating quality of life, noncompliance and data on the costs and benefits of chemotherapy. We used a probabilistic Markov model to estimate the costs and quality-adjusted life expectancy of 50-year-old average-risk Canadians without screening and with screening by each test. We populated the model with data from the published literature. We calculated costs from the perspective of a third-party payer, with inflation to 2007 Canadian dollars. Of the 10 strategies considered, we focused on three tests currently being used for population screening in some Canadian provinces: low-sensitivity guaiac fecal occult blood test, performed annually; fecal immunochemical test, performed annually; and colonoscopy, performed every 10 years. These strategies reduced the incidence of colorectal cancer by 44%, 65% and 81%, and mortality by 55%, 74% and 83%, respectively, compared with no screening. These strategies generated incremental cost-effectiveness ratios of $9159, $611 and $6133 per quality-adjusted life year, respectively. The findings were robust to probabilistic sensitivity analysis. Colonoscopy every 10 years yielded the greatest net health benefit. Screening for colorectal cancer is cost-effective over conventional levels of willingness to pay. Annual high-sensitivity fecal occult blood testing, such as a fecal immunochemical test, or colonoscopy every 10 years offer the best value for the money in Canada.

Cost effectiveness and projected national impact of colorectal cancer screening in France.

PubMed

Hassan, C; Benamouzig, R; Spada, C; Ponchon, T; Zullo, A; Saurin, J C; Costamagna, G

2011-09-01

Colorectal cancer (CRC) is a major cause of morbidity and mortality in France. Only scanty data on cost-effectiveness of CRC screening in Europe are available, generating uncertainty over its efficiency. Although immunochemical fecal tests (FIT) and guaiac-based fecal occult blood tests (g-FOBT) have been shown to be cost-effective in France, cost-effectiveness of endoscopic screening has not yet been addressed. Cost-effectiveness of screening strategies using colonoscopy, flexible sigmoidoscopy, second-generation colon capsule endoscopy (CCE), FIT and g-FOBT were compared using a Markov model. A 40 % adherence rate was assumed for all strategies. Colonoscopy costs included anesthesiologist assistance. Incremental cost-effectiveness ratios (ICERs) were calculated. Probabilistic and value-of-information analyses were used to estimate the expected benefit of future research. A third-payer perspective was adopted. In the reference case analysis, FIT repeated every year was the most cost-effective strategy, with an ICER of €48165 per life-year gained vs. FIT every 2 years, which was the next most cost-effective strategy. Although CCE every 5 years was as effective as FIT 1-year, it was not a cost-effective alternative. Colonoscopy repeated every 10 years was substantially more costly, and slightly less effective than FIT 1-year. When projecting the model outputs onto the French population, the least (g-FOBT 2-years) and most (FIT 1-year) effective strategies reduced the absolute number of annual CRC deaths from 16037 to 12916 and 11217, respectively, resulting in an annual additional cost of €26 million and €347 million, respectively. Probabilistic sensitivity analysis demonstrated that FIT 1-year was the optimal choice in 20% of the simulated scenarios, whereas sigmoidoscopy 5-years, colonoscopy, and FIT 2-years were the optimal choices in 40%, 26%, and 14%, respectively. A screening program based on FIT 1-year appeared to be the most cost-effective approach for CRC screening in France. However, a substantial uncertainty over this choice is still present. © Georg Thieme Verlag KG Stuttgart · New York.

What weight should be assigned to future environmental impacts? A probabilistic cost benefit analysis using recent advances on discounting.

PubMed

Almansa, Carmen; Martínez-Paz, José M

2011-03-01

Cost-benefit analysis is a standard methodological platform for public investment evaluation. In high environmental impact projects, with a long-term effect on future generations, the choice of discount rate and time horizon is of particular relevance, because it can lead to very different profitability assessments. This paper describes some recent approaches to environmental discounting and applies them, together with a number of classical procedures, to the economic evaluation of a plant for the desalination of irrigation return water from intensive farming, aimed at halting the degradation of an area of great ecological value, the Mar Menor, in South Eastern Spain. A Monte Carlo procedure is used in four CBA approaches and three time horizons to carry out a probabilistic sensitivity analysis designed to integrate the views of an international panel of experts in environmental discounting with the uncertainty affecting the market price of the project's main output, i.e., irrigation water for a water-deprived area. The results show which discounting scenarios most accurately estimate the socio-environmental profitability of the project while also considering the risk associated with these two key parameters. The analysis also provides some methodological findings regarding ways of assessing financial and environmental profitability in decisions concerning public investment in the environment. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparison of the levonorgestrel-releasing intrauterine system, hysterectomy, and endometrial ablation for heavy menstrual bleeding in a decision analysis model.

PubMed

Louie, Michelle; Spencer, Jennifer; Wheeler, Stephanie; Ellis, Victoria; Toubia, Tarek; Schiff, Lauren D; Siedhoff, Matthew T; Moulder, Janelle K

2017-11-01

A better understanding of the relative risks and benefits of common treatment options for abnormal uterine bleeding (AUB) can help providers and patients to make balanced, evidence-based decisions. To provide comparative estimates of clinical outcomes after placement of levonorgestrel-releasing intrauterine system (LNG-IUS), ablation, or hysterectomy for AUB. A PubMED search was done using combinations of search terms related to abnormal uterine bleeding, LNG-IUS, hysterectomy, endometrial ablation, cost-benefit analysis, cost-effectiveness, and quality-adjusted life years. Full articles published in 2006-2016 available in English comparing at least two treatment modalities of interest among women of reproductive age with AUB were included. A decision tree was generated to compare clinical outcomes in a hypothetical cohort of 100 000 premenopausal women with nonmalignant AUB. We evaluated complications, mortality, and treatment outcomes over a 5-year period, calculated cumulative quality-adjusted life years (QALYs), and conducted probabilistic sensitivity analysis. Levonorgestrel-releasing intrauterine system had the highest number of QALYs (406 920), followed by hysterectomy (403 466), non-resectoscopic ablation (399 244), and resectoscopic ablation (395 827). Ablation had more treatment failures and complications than LNG-IUS and hysterectomy. Findings were robust in probabilistic sensitivity analysis. Levonorgestrel-releasing intrauterine system and hysterectomy outperformed endometrial ablation for treatment of AUB. © 2017 International Federation of Gynecology and Obstetrics.

Economic evaluation of first-line adjuvant chemotherapies for resectable gastric cancer patients in China.

PubMed

Tan, Chongqing; Peng, Liubao; Zeng, Xiaohui; Li, Jianhe; Wan, Xiaomin; Chen, Gannong; Yi, Lidan; Luo, Xia; Zhao, Ziying

2013-01-01

First-line postoperative adjuvant chemotherapies with S-1 and capecitabine and oxaliplatin (XELOX) were first recommended for resectable gastric cancer patients in the 2010 and 2011 Chinese NCCN Clinical Practice Guidelines in Oncology: Gastric Cancer; however, their economic impact in China is unknown. The aim of this study was to compare the cost-effectiveness of adjuvant chemotherapy with XELOX, with S-1 and no treatment after a gastrectomy with extended (D2) lymph-node dissection among patients with stage II-IIIB gastric cancer. A Markov model, based on data from two clinical phase III trials, was developed to analyse the cost-effectiveness of patients in the XELOX group, S-1 group and surgery only (SO) group. The costs were estimated from the perspective of Chinese healthcare system. The utilities were assumed on the basis of previously published reports. Costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICER) were calculated with a lifetime horizon. One-way and probabilistic sensitivity analyses were performed. For the base case, XELOX had the lowest total cost ($44,568) and cost-effectiveness ratio ($7,360/QALY). The relative scenario analyses showed that SO was dominated by XELOX and the ICERs of S-1 was $58,843/QALY compared with XELOX. The one-way sensitivity analysis showed that the most influential parameter was the utility of disease-free survival. The probabilistic sensitivity analysis predicted a 75.8% likelihood that the ICER for XELOX would be less than $13,527 compared with S-1. When ICER was more than $38,000, the likelihood of cost-effectiveness achieved by S-1 group was greater than 50%. Our results suggest that for patients in China with resectable disease, first-line adjuvant chemotherapy with XELOX after a D2 gastrectomy is a best option comparing with S-1 and SO in view of our current study. In addition, S-1 might be a better choice, especially with a higher value of willingness-to-pay threshold.

Cost-Effectiveness Analysis of Chemoradiation Therapy Versus Transoral Robotic Surgery for Human Papillomavirus–Associated, Clinical N2 Oropharyngeal Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sher, David J., E-mail: david.sher@utsouthwestern.edu; Fidler, Mary Jo; Tishler, Roy B.

Purpose: To perform a cost-effectiveness analysis of primary chemoradiation therapy (CRT) versus transoral robotic surgery (TORS) for clinical N2, human papillomavirus (HPV)-positive oropharyngeal carcinoma. Methods and Materials: We developed a Markov model to describe the health states after treatment with CRT or TORS, followed by adjuvant radiation therapy or CRT in the presence of high-risk pathology (positive margins or extracapsular extension). Outcomes, toxicities, and costs were extracted from the literature. One-way sensitivity analyses (SA) were performed over a wide range of parameters, as were 2-way SA between the key variables. Probabilistic SA and value of information studies were performed over keymore » parameters. Results: The expected quality-adjusted life years (QALYs)/total costs for CRT and TORS were 7.31/$50,100 and 7.29/$62,200, respectively, so that CRT dominated TORS. In SA, primary CRT was almost always cost-effective up to a societal willingness-to-pay of $200,000/QALY, unless the locoregional recurrence risk after TORS was 30% to 50% lower, at which point it became cost effective at a willingness-to-pay of $50-100,000/QALY. Probabilistic SA confirmed the importance of locoregional recurrence risk, and the value of information in precisely knowing this parameter was more than $7M per year. If the long-term utility after TORS was 0.03 lower than CRT, CRT was cost-effective over nearly any assumption. Conclusions: Under nearly all assumptions, primary CRT was the cost-effective therapy for HPV-associated, clinical N2 OPC. However, in the hypothetical event of a large relative improvement in LRR with surgery and equivalent long-term utilities, primary TORS would become the higher-value treatment, arguing for prospective, comparative study of the 2 paradigms.« less

Economic evaluation of nivolumab as a second-line treatment for advanced renal cell carcinoma from US and Chinese perspectives.

PubMed

Wan, Xiao Min; Peng, Liu Bao; Ma, Jin An; Li, Yuan Jian

2017-07-15

Nivolumab is a new standard of care for patients with metastatic renal cell carcinoma (mRCC) and provides an overall survival benefit of 5.40 months in comparison with everolimus. This study evaluated the cost-effectiveness of nivolumab for the second-line treatment of mRCC from the perspective of US payers and identified the range of drug costs for which the addition of nivolumab to standard therapy could be considered cost-effective from a Chinese perspective. A partitioned survival model was constructed to estimate lifetime costs, life-years, and quality-adjusted life-years (QALYs). Costs were estimated for the US and Chinese health care systems. One-way and probabilistic sensitivity analyses were performed. Nivolumab provided an additional 0.29 QALYs at a cost of $151,676/QALY in the United States. The probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of $100,000/QALY, at the current cost of nivolumab, the chance of nivolumab being cost-effective was 3.10%. For China, when nivolumab cost less than $7.90 or $9.70/mg, there was a nearly 90% likelihood that the incremental cost-effectiveness ratio for nivolumab would be less than $22,785 or $48,838/QALY, respectively. For the United States, nivolumab is unlikely to be a high-value treatment for mRCC at the current price, and a price reduction appears to be justified. In China, value-based prices for nivolumab are $7.90 and $9.70/mg for the country and Beijing City, respectively. This study could and should inform the multilateral drug-price negotiations in China that may be upcoming for nivolumab. Cancer 2017;123:2634-41. © 2017 American Cancer Society. © 2017 American Cancer Society.

Cost-Utility of Quadrivalent Versus Trivalent Influenza Vaccine in Germany, Using an Individual-Based Dynamic Transmission Model.

PubMed

Dolk, Christiaan; Eichner, Martin; Welte, Robert; Anastassopoulou, Anastassia; Van Bellinghen, Laure-Anne; Poulsen Nautrup, Barbara; Van Vlaenderen, Ilse; Schmidt-Ott, Ruprecht; Schwehm, Markus; Postma, Maarten

2016-12-01

Seasonal influenza infection is primarily caused by circulation of two influenza A strain subtypes and strains from two B lineages that vary each year. Trivalent influenza vaccine (TIV) contains only one of the two B-lineage strains, resulting in mismatches between vaccine strains and the predominant circulating B lineage. Quadrivalent influenza vaccine (QIV) includes both B-lineage strains. The objective was to estimate the cost-utility of introducing QIV to replace TIV in Germany. An individual-based dynamic transmission model (4Flu) using German data was used to provide realistic estimates of the impact of TIV and QIV on age-specific influenza infections. Cases were linked to health and economic outcomes to calculate the cost-utility of QIV versus TIV, from both a societal and payer perspective. Costs and effects were discounted at 3.0 and 1.5 % respectively, with 2014 as the base year. Univariate and probabilistic sensitivity analyses were conducted. Using QIV instead of TIV resulted in additional quality-adjusted life-years (QALYs) and cost savings from the societal perspective (i.e. it represents the dominant strategy) and an incremental cost-utility ratio (ICUR) of €14,461 per QALY from a healthcare payer perspective. In all univariate analyses, QIV remained cost-effective (ICUR <€50,000). In probabilistic sensitivity analyses, QIV was cost-effective in >98 and >99 % of the simulations from the societal and payer perspective, respectively. This analysis suggests that QIV in Germany would provide additional health gains while being cost-saving to society or costing €14,461 per QALY gained from the healthcare payer perspective, compared with TIV.

Cost-effectiveness of clopidogrel-aspirin versus aspirin alone for acute transient ischemic attack and minor stroke.

PubMed

Pan, Yuesong; Wang, Anxin; Liu, Gaifen; Zhao, Xingquan; Meng, Xia; Zhao, Kun; Liu, Liping; Wang, Chunxue; Johnston, S Claiborne; Wang, Yilong; Wang, Yongjun

2014-06-05

Treatment with the combination of clopidogrel and aspirin taken soon after a transient ischemic attack (TIA) or minor stroke was shown to reduce the 90-day risk of stroke in a large trial in China, but the cost-effectiveness is unknown. This study sought to estimate the cost-effectiveness of the clopidogrel-aspirin regimen for acute TIA or minor stroke. A Markov model was created to determine the cost-effectiveness of treatment of acute TIA or minor stroke patients with clopidogrel-aspirin compared with aspirin alone. Inputs for the model were obtained from clinical trial data, claims databases, and the published literature. The main outcome measure was cost per quality-adjusted life-years (QALYs) gained. One-way and multivariable probabilistic sensitivity analyses were performed to test the robustness of the findings. Compared with aspirin alone, clopidogrel-aspirin resulted in a lifetime gain of 0.037 QALYs at an additional cost of CNY 1250 (US$ 192), yielding an incremental cost-effectiveness ratio of CNY 33 800 (US$ 5200) per QALY gained. Probabilistic sensitivity analysis showed that clopidogrel-aspirin therapy was more cost-effective in 95.7% of the simulations at a willingness-to-pay threshold recommended by the World Health Organization of CNY 105 000 (US$ 16 200) per QALY. Early 90-day clopidogrel-aspirin regimen for acute TIA or minor stroke is highly cost-effective in China. Although clopidogrel is generic, Plavix is brand in China. If Plavix were generic, treatment with clopidogrel-aspirin would have been cost saving. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Economic analysis of continuous antibiotic prophylaxis for prevention of urinary tract infections in infants with high-grade hydronephrosis.

PubMed

Tu, H Y V; Pemberton, J; Lorenzo, A J; Braga, L H

2015-10-01

For infants with hydronephrosis, continuous antibiotic prophylaxis (CAP) may reduce urinary tract infections (UTIs); however, its value remains controversial. Recent studies have suggested that neonates with severe obstructive hydronephrosis are at an increased risk of UTIs, and support the use of CAP. Other studies have demonstrated the negligible risk for UTIs in the setting of suspected ureteropelvic junction obstruction and have highlighted the limited role of CAP in hydronephrosis. Furthermore, economic studies in this patient population have been sparse. This study aimed to evaluate whether the use of CAP is an efficient expenditure for preventing UTIs in children with high-grade hydronephrosis within the first 2 years of life. A decision model was used to estimate expected costs, clinical outcomes and quality-adjusted life years (QALYs) of CAP versus no CAP (Fig. 1). Cost data were collected from provincial databases and converted to 2013 Canadian dollars (CAD). Estimates of risks and health utility values were extracted from published literature. The analysis was performed over a time horizon of 2 years. One-way and probabilistic sensitivity analyses were carried out to assess uncertainty and robustness. Overall, CAP use was less costly and provided a minimal increase in health utility when compared to no CAP (Table). The mean cost over two years for CAP and no CAP was CAD$1571.19 and CAD$1956.44, respectively. The use of CAP reduced outpatient-managed UTIs by 0.21 infections and UTIs requiring hospitalization by 0.04 infections over 2 years. Cost-utility analysis revealed an increase of 0.0001 QALYs/year when using CAP. The CAP arm exhibited strong dominance over no CAP in all sensitivity analyses and across all willingness-to-pay thresholds. The use of CAP exhibited strong dominance in the economic evaluation, despite a small gain of 0.0001 QALYs/year. Whether this slight gain is clinically significant remains to be determined. However, small QALY gains have been reported in other pediatric economic evaluations. Strengths of this study included the use of data from a recent systematic review and meta-analysis, in addition to a comprehensive probabilistic sensitivity analysis. Limitations of this study included the use of estimates for UTI probabilities in the second year of life and health utility values, given that they were lacking in the literature. Spontaneous resolution of hydronephrosis and surgical management were also not implemented in this model. To prevent UTIs within the first 2 years of life in infants with high-grade hydronephrosis, this probabilistic model has shown that CAP use is a prudent expenditure of healthcare resources when compared to no CAP. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Latin American Clinical Epidemiology Network Series - Paper 8: Ticagrelor was cost-effective vs. clopidogrel in acute coronary syndrome in Chile.

PubMed

De la Puente, Catherine; Vallejos, Carlos; Bustos, Luis; Zaror, Carlos; Velasquez, Monica; Lanas, Fernando

2017-06-01

To evaluate the incremental cost-effectiveness ratio (ICER) of the use of ticagrelor as a substitute for clopidogrel for secondary prevention of acute coronary syndrome in Chile. Cost-effectiveness analysis based on a Markov model: Safety and effectiveness data of ticagrelor were obtained from a systematic review of the literature. Costs are expressed in Chilean pesos (CLP) as of 2013. The evaluation was conducted from the payer standpoint. A probabilistic sensitivity analysis comprising discount rates and national cost variability was done. A budget impact analysis estimated for 2015 was conducted to calculate the total cost for both treatments. The ICER with a discount rate of 6% for ticagrelor vs. clopidogrel was CLP 4,893,126 per quality-adjusted life-year (QALY) gained (=9,689 US$). In the budget impact analysis for the baseline scenario, considering 100% of treatment, coverage, and adherence, ticagrelor represented an additional cost of CLP 5,233,854,272, for 979 QALYs gained compared with clopidogrel. Ticagrelor is cost-effective in comparison with clopidogrel for the secondary prevention of acute coronary syndrome. These findings are similar to those reported in other international cost-effectiveness studies. Copyright © 2016 Elsevier Inc. All rights reserved.

An Assessment of the Expected Cost-Effectiveness of Quadrivalent Influenza Vaccines in Ontario, Canada Using a Static Model.

PubMed

Chit, Ayman; Roiz, Julie; Aballea, Samuel

2015-01-01

Ontario, Canada, immunizes against influenza using a trivalent inactivated influenza vaccine (IIV3) under a Universal Influenza Immunization Program (UIIP). The UIIP offers IIV3 free-of-charge to all Ontarians over 6 months of age. A newly approved quadrivalent inactivated influenza vaccine (IIV4) offers wider protection against influenza B disease. We explored the expected cost-utility and budget impact of replacing IIV3 with IIV4, within the context of Ontario's UIIP, using a probabilistic and static cost-utility model. Wherever possible, epidemiological and cost data were obtained from Ontario sources. Canadian or U.S. sources were used when Ontario data were not available. Vaccine efficacy for IIV3 was obtained from the literature. IIV4 efficacy was derived from meta-analysis of strain-specific vaccine efficacy. Conservatively, herd protection was not considered. In the base case, we used IIV3 and IIV4 prices of $5.5/dose and $7/dose, respectively. We conducted a sensitivity analysis on the price of IIV4, as well as standard univariate and multivariate statistical uncertainty analyses. Over a typical influenza season, relative to IIV3, IIV4 is expected to avert an additional 2,516 influenza cases, 1,683 influenza-associated medical visits, 27 influenza-associated hospitalizations, and 5 influenza-associated deaths. From a societal perspective, IIV4 would generate 76 more Quality Adjusted Life Years (QALYs) and a net societal budget impact of $4,784,112. The incremental cost effectiveness ratio for this comparison was $63,773/QALY. IIV4 remains cost-effective up to a 53% price premium over IIV3. A probabilistic sensitivity analysis showed that IIV4 was cost-effective with a probability of 65% for a threshold of $100,000/QALY gained. IIV4 is expected to achieve reductions in influenza-related morbidity and mortality compared to IIV3. Despite not accounting for herd protection, IIV4 is still expected to be a cost-effective alternative to IIV3 up to a price premium of 53%. Our conclusions were robust in the face of sensitivity analyses.

Cost-effectiveness of daclatasvir plus sofosbuvir-based regimen for treatment of hepatitis C virus genotype 3 infection in Canada.

PubMed

Moshyk, A; Martel, M-J; Tahami Monfared, A A; Goeree, R

2016-01-01

New regimens for the treatment of chronic hepatitis C virus (HCV) genotype 3 have demonstrated substantial improvement in sustained virologic response (SVR) compared with existing therapies, but are considerably more expensive. The objective of this study was to evaluate the cost-effectiveness of two novel all-oral, interferon-free regimens for the treatment of patients with HCV genotype 3: daclatasvir plus sofosbuvir (DCV + SOF) and sofosbuvir plus ribavirin (SOF + RBV), from a Canadian health-system perspective. A decision analytic Markov model was developed to compare the effect of various treatment strategies on the natural history of the disease and their associated costs in treatment-naïve and treatment-experienced patients. Patients were initially distributed across fibrosis stages F0-F4, and may incur disease progression through fibrosis stages and on to end-stage liver disease complications and death; or may achieve SVR. Clinical efficacy, health-related quality-of-life, costs, and transition probabilities were based on published literature. Probabilistic sensitivity analysis was performed to assess parameter uncertainty associated with the analysis. In treatment-naive patients, the expected quality-adjusted life years (QALYs) for interferon-free regimens were higher for DCV + SOF (12.37) and SOF + RBV (12.48) compared to that of pINF + RBV (11.71) over a lifetime horizon, applying their clinical trial treatment durations. The expected costs were higher for DCV + SOF ($170,371) and SOF + RBV ($194,776) vs pINF + RBV regimen ($90,905). Compared to pINF + RBV, the incremental cost-effectiveness ratios (ICER) were $120,671 and $135,398 per QALYs for DCV + SOF and SOF + RBV, respectively. In treatment-experienced patients, DCV + SOF regimen dominated the SOF + RBV regimen. Probabilistic sensitivity analysis indicated a 100% probability that a DCV + SOF regimen was cost saving in treatment-experienced patients. Daclatasvir plus sofosbuvir is a safe and effective option for the treatment of chronic HCV genotype 3 patients. This regimen could be considered a cost-effective option following a first-line treatment of peg-interferon/ribavirin treatment experienced patients with HCV genotype-3 infection.

Defining the Value of Future Research to Identify the Preferred Treatment of Meniscal Tear in the Presence of Knee Osteoarthritis

PubMed Central

Losina, Elena; Dervan, Elizabeth E.; Paltiel, A. David; Dong, Yan; Wright, R. John; Spindler, Kurt P.; Mandl, Lisa A.; Jones, Morgan H.; Marx, Robert G.; Safran-Norton, Clare E.; Katz, Jeffrey N.

2015-01-01

Background Arthroscopic partial meniscectomy (APM) is extensively used to relieve pain in patients with symptomatic meniscal tear (MT) and knee osteoarthritis (OA). Recent studies have failed to show the superiority of APM compared to other treatments. We aim to examine whether existing evidence is sufficient to reject use of APM as a cost-effective treatment for MT+OA. Methods We built a patient-level microsimulation using Monte Carlo methods and evaluated three strategies: Physical therapy (‘PT’) alone; PT followed by APM if subjects continued to experience pain (‘Delayed APM’); and ‘Immediate APM’. Our subject population was US adults with symptomatic MT and knee OA over a 10 year time horizon. We assessed treatment outcomes using societal costs, quality-adjusted life years (QALYs), and calculated incremental cost-effectiveness ratios (ICERs), incorporating productivity costs as a sensitivity analysis. We also conducted a value-of-information analysis using probabilistic sensitivity analyses. Results Calculated ICERs were estimated to be $12,900/QALY for Delayed APM as compared to PT and $103,200/QALY for Immediate APM as compared to Delayed APM. In sensitivity analyses, inclusion of time costs made Delayed APM cost-saving as compared to PT. Improving efficacy of Delayed APM led to higher incremental costs and lower incremental effectiveness of Immediate APM in comparison to Delayed APM. Probabilistic sensitivity analyses indicated that PT had 3.0% probability of being cost-effective at a willingness-to-pay (WTP) threshold of $50,000/QALY. Delayed APM was cost effective 57.7% of the time at WTP = $50,000/QALY and 50.2% at WTP = $100,000/QALY. The probability of Immediate APM being cost-effective did not exceed 50% unless WTP exceeded $103,000/QALY. Conclusions We conclude that current cost-effectiveness evidence does not support unqualified rejection of either Immediate or Delayed APM for the treatment of MT+OA. The amount to which society would be willing to pay for additional information on treatment outcomes greatly exceeds the cost of conducting another randomized controlled trial on APM. PMID:26086246

Classic articles and workbook: EPRI monographs on simulation of electric power production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stremel, J.P.

1991-12-01

This monograph republishes several articles including a seminal one on probabilistic production costing for electric power generation. That article is given in the original French along with a English translation. Another article, written by R. Booth, gives a popular explanation of the theory, and a workbook by B. Manhire is included that carries through a simple example step by step. The classical analysis of non-probabilistic generator dispatch by L.K. Kirchmayer is republished along with an introductory essay by J.P. Stremel that puts in perspective the monograph material. The article in French was written by H. Baleriaux, E. Jamoulle, and Fr.more » Linard de Guertechin and first published in Brussels in 1967. It derived a method for calculating the expected value of production costs by modifying a load duration curve through the use of probability factors that account for unplanned random generator outages. Although the paper showed how pump storage plants could be included and how linear programming could be applied, the convolution technique used in the probabilistic calculations is the part most widely applied. The tutorial paper by Booth was written in a light style, and its lucidity helped popularize the method. The workbook by Manhire also shows how the calculation can be shortened significantly using cumulants to approximate the load duration curve.« less

Techno-economic and Monte Carlo probabilistic analysis of microalgae biofuel production system.

PubMed

Batan, Liaw Y; Graff, Gregory D; Bradley, Thomas H

2016-11-01

This study focuses on the characterization of the technical and economic feasibility of an enclosed photobioreactor microalgae system with annual production of 37.85 million liters (10 million gallons) of biofuel. The analysis characterizes and breaks down the capital investment and operating costs and the production cost of unit of algal diesel. The economic modelling shows total cost of production of algal raw oil and diesel of $3.46 and $3.69 per liter, respectively. Additionally, the effects of co-products' credit and their impact in the economic performance of algal-to-biofuel system are discussed. The Monte Carlo methodology is used to address price and cost projections and to simulate scenarios with probabilities of financial performance and profits of the analyzed model. Different markets for allocation of co-products have shown significant shifts for economic viability of algal biofuel system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of Adaptive Intraply Hybrid Fiber Composites with Reliability Considerations

NASA Technical Reports Server (NTRS)

Shiao, Michael C.; Chamis, Christos C.

1994-01-01

The reliability with bounded distribution parameters (mean, standard deviation) was maximized and the reliability-based cost was minimized for adaptive intra-ply hybrid fiber composites by using a probabilistic method. The probabilistic method accounts for all naturally occurring uncertainties including those in constituent material properties, fabrication variables, structure geometry, and control-related parameters. Probabilistic sensitivity factors were computed and used in the optimization procedures. For actuated change in the angle of attack of an airfoil-like composite shell structure with an adaptive torque plate, the reliability was maximized to 0.9999 probability, with constraints on the mean and standard deviation of the actuation material volume ratio (percentage of actuation composite material in a ply) and the actuation strain coefficient. The reliability-based cost was minimized for an airfoil-like composite shell structure with an adaptive skin and a mean actuation material volume ratio as the design parameter. At a O.9-mean actuation material volume ratio, the minimum cost was obtained.

Nine steps to risk-informed wellhead protection and management: Methods and application to the Burgberg Catchment

NASA Astrophysics Data System (ADS)

Nowak, W.; Enzenhoefer, R.; Bunk, T.

2013-12-01

Wellhead protection zones are commonly delineated via advective travel time analysis without considering any aspects of model uncertainty. In the past decade, research efforts produced quantifiable risk-based safety margins for protection zones. They are based on well vulnerability criteria (e.g., travel times, exposure times, peak concentrations) cast into a probabilistic setting, i.e., they consider model and parameter uncertainty. Practitioners still refrain from applying these new techniques for mainly three reasons. (1) They fear the possibly cost-intensive additional areal demand of probabilistic safety margins, (2) probabilistic approaches are allegedly complex, not readily available, and consume huge computing resources, and (3) uncertainty bounds are fuzzy, whereas final decisions are binary. The primary goal of this study is to show that these reservations are unjustified. We present a straightforward and computationally affordable framework based on a novel combination of well-known tools (e.g., MODFLOW, PEST, Monte Carlo). This framework provides risk-informed decision support for robust and transparent wellhead delineation under uncertainty. Thus, probabilistic risk-informed wellhead protection is possible with methods readily available for practitioners. As vivid proof of concept, we illustrate our key points on a pumped karstic well catchment, located in Germany. In the case study, we show that reliability levels can be increased by re-allocating the existing delineated area at no increase in delineated area. This is achieved by simply swapping delineated low-risk areas against previously non-delineated high-risk areas. Also, we show that further improvements may often be available at only low additional delineation area. Depending on the context, increases or reductions of delineated area directly translate to costs and benefits, if the land is priced, or if land owners need to be compensated for land use restrictions.

Failure Bounding And Sensitivity Analysis Applied To Monte Carlo Entry, Descent, And Landing Simulations

NASA Technical Reports Server (NTRS)

Gaebler, John A.; Tolson, Robert H.

2010-01-01

In the study of entry, descent, and landing, Monte Carlo sampling methods are often employed to study the uncertainty in the designed trajectory. The large number of uncertain inputs and outputs, coupled with complicated non-linear models, can make interpretation of the results difficult. Three methods that provide statistical insights are applied to an entry, descent, and landing simulation. The advantages and disadvantages of each method are discussed in terms of the insights gained versus the computational cost. The first method investigated was failure domain bounding which aims to reduce the computational cost of assessing the failure probability. Next a variance-based sensitivity analysis was studied for the ability to identify which input variable uncertainty has the greatest impact on the uncertainty of an output. Finally, probabilistic sensitivity analysis is used to calculate certain sensitivities at a reduced computational cost. These methods produce valuable information that identifies critical mission parameters and needs for new technology, but generally at a significant computational cost.

Comparison of Control Approaches in Genetic Regulatory Networks by Using Stochastic Master Equation Models, Probabilistic Boolean Network Models and Differential Equation Models and Estimated Error Analyzes

NASA Astrophysics Data System (ADS)

Caglar, Mehmet Umut; Pal, Ranadip

2011-03-01

Central dogma of molecular biology states that ``information cannot be transferred back from protein to either protein or nucleic acid''. However, this assumption is not exactly correct in most of the cases. There are a lot of feedback loops and interactions between different levels of systems. These types of interactions are hard to analyze due to the lack of cell level data and probabilistic - nonlinear nature of interactions. Several models widely used to analyze and simulate these types of nonlinear interactions. Stochastic Master Equation (SME) models give probabilistic nature of the interactions in a detailed manner, with a high calculation cost. On the other hand Probabilistic Boolean Network (PBN) models give a coarse scale picture of the stochastic processes, with a less calculation cost. Differential Equation (DE) models give the time evolution of mean values of processes in a highly cost effective way. The understanding of the relations between the predictions of these models is important to understand the reliability of the simulations of genetic regulatory networks. In this work the success of the mapping between SME, PBN and DE models is analyzed and the accuracy and affectivity of the control policies generated by using PBN and DE models is compared.

Cost-effectiveness and budget impact of the fixed-dose dual bronchodilator combination tiotropium-olodaterol for patients with COPD in the Netherlands.

PubMed

van Boven, Job Fm; Kocks, Janwillem Wh; Postma, Maarten J

2016-01-01

The fixed-dose dual bronchodilator combination (FDC) of tiotropium and olodaterol showed increased effectiveness regarding lung function and health-related quality of life in patients with chronic obstructive pulmonary disease (COPD) compared with the use of its mono-components. Yet, while effectiveness and safety have been shown, the health economic implication of this treatment is still unknown. The aim of this study was to assess the cost-utility and budget impact of tiotropium-olodaterol FDC in patients with moderate to very severe COPD in the Netherlands. A cost-utility study was performed, using an individual-level Markov model. To populate the model, individual patient-level data (age, height, sex, COPD duration, baseline forced expiratory volume in 1 second) were obtained from the tiotropium-olodaterol TOnado trial. In the model, forced expiratory volume in 1 second and patient-level data were extrapolated to utility and survival, and treatment with tiotropium-olodaterol FDC was compared with tiotropium. Cost-utility analysis was performed from the Dutch health care payer's perspective using a 15-year time horizon in the base-case analysis. The standard Dutch discount rates were applied (costs: 4.0%; effects: 1.5%). Both univariate and probabilistic sensitivity analyses were performed. Budget impact was annually assessed over a 5-year time horizon, taking into account different levels of medication adherence. As a result of cost increases, combined with quality-adjusted life-year (QALY) gains, results showed that tiotropium-olodaterol FDC had an incremental cost-effectiveness ratio of €7,004/QALY. Without discounting, the incremental cost-effectiveness ratio was €5,981/QALY. Results were robust in univariate and probabilistic sensitivity analyses. Budget impact was estimated at €4.3 million over 5 years assuming 100% medication adherence. Scenarios with 40%, 60%, and 80% adherence resulted in lower 5-year incremental cost increases of €1.7, €2.6, and €3.4 million, respectively. Tiotropium-olodaterol FDC can be considered a cost-effective treatment under current Dutch cost-effectiveness thresholds.

Probabilistic Aeroelastic Analysis of Turbomachinery Components

NASA Technical Reports Server (NTRS)

Reddy, T. S. R.; Mital, S. K.; Stefko, G. L.

2004-01-01

A probabilistic approach is described for aeroelastic analysis of turbomachinery blade rows. Blade rows with subsonic flow and blade rows with supersonic flow with subsonic leading edge are considered. To demonstrate the probabilistic approach, the flutter frequency, damping and forced response of a blade row representing a compressor geometry is considered. The analysis accounts for uncertainties in structural and aerodynamic design variables. The results are presented in the form of probabilistic density function (PDF) and sensitivity factors. For subsonic flow cascade, comparisons are also made with different probabilistic distributions, probabilistic methods, and Monte-Carlo simulation. The approach shows that the probabilistic approach provides a more realistic and systematic way to assess the effect of uncertainties in design variables on the aeroelastic instabilities and response.

Cost-Effectiveness of Mirabegron Compared with Antimuscarinic Agents for the Treatment of Adults with Overactive Bladder in the United Kingdom.

PubMed

Nazir, Jameel; Maman, Khaled; Neine, Mohamed-Elmoctar; Briquet, Benjamin; Odeyemi, Isaac A O; Hakimi, Zalmai; Garnham, Andy; Aballéa, Samuel

2015-09-01

Mirabegron, a first-in-class selective oral β3-adrenoceptor agonist, has similar efficacy to most antimuscarinic agents and a lower incidence of dry mouth in patients with overactive bladder (OAB). To evaluate the cost-effectiveness of mirabegron 50 mg compared with oral antimuscarinic agents in adults with OAB from a UK National Health Service perspective. A Markov model including health states for symptom severity, treatment status, and adverse events was developed. Cycle length was 1 month, and the time horizon was 5 years. Antimuscarinic comparators were tolterodine extended release, solifenacin, fesoterodine, oxybutynin extended release and immediate release (IR), darifenacin, and trospium chloride modified release. Transition probabilities for symptom severity levels and adverse events were estimated from a mirabegron trial and a mixed treatment comparison. Estimates for other inputs were obtained from published literature or expert opinion. Quality-adjusted life-years (QALYs) and total health care costs, including costs of drug acquisition, physician visits, incontinence pad use, and botox injections, were modeled. Deterministic and probabilistic sensitivity analyses were performed. Base-case incremental cost-effectiveness ratios ranged from £367 (vs. solifenacin 10 mg) to £15,593 (vs. oxybutynin IR 10 mg) per QALY gained. Probabilistic sensitivity analyses showed that at a willingness-to-pay threshold of £20,000/QALY gained, the probability of mirabegron 50 mg being cost-effective ranged from 70.2% versus oxybutynin IR 10 mg to 97.8% versus darifenacin 15 mg. A limitation of our analysis is the uncertainty due to the lack of direct comparisons of mirabegron with other agents; a mixed treatment comparison using rigorous methodology provided the data for the analysis, but the studies involved showed heterogeneity. Mirabegron 50 mg appears to be cost-effective compared with standard oral antimuscarinic agents for the treatment of adults with OAB from a UK National Health Service perspective. Copyright © 2015. Published by Elsevier Inc.

A comparison of two methods for expert elicitation in health technology assessments.

PubMed

Grigore, Bogdan; Peters, Jaime; Hyde, Christopher; Stein, Ken

2016-07-26

When data needed to inform parameters in decision models are lacking, formal elicitation of expert judgement can be used to characterise parameter uncertainty. Although numerous methods for eliciting expert opinion as probability distributions exist, there is little research to suggest whether one method is more useful than any other method. This study had three objectives: (i) to obtain subjective probability distributions characterising parameter uncertainty in the context of a health technology assessment; (ii) to compare two elicitation methods by eliciting the same parameters in different ways; (iii) to collect subjective preferences of the experts for the different elicitation methods used. Twenty-seven clinical experts were invited to participate in an elicitation exercise to inform a published model-based cost-effectiveness analysis of alternative treatments for prostate cancer. Participants were individually asked to express their judgements as probability distributions using two different methods - the histogram and hybrid elicitation methods - presented in a random order. Individual distributions were mathematically aggregated across experts with and without weighting. The resulting combined distributions were used in the probabilistic analysis of the decision model and mean incremental cost-effectiveness ratios and the expected values of perfect information (EVPI) were calculated for each method, and compared with the original cost-effectiveness analysis. Scores on the ease of use of the two methods and the extent to which the probability distributions obtained from each method accurately reflected the expert's opinion were also recorded. Six experts completed the task. Mean ICERs from the probabilistic analysis ranged between £162,600-£175,500 per quality-adjusted life year (QALY) depending on the elicitation and weighting methods used. Compared to having no information, use of expert opinion decreased decision uncertainty: the EVPI value at the £30,000 per QALY threshold decreased by 74-86 % from the original cost-effectiveness analysis. Experts indicated that the histogram method was easier to use, but attributed a perception of more accuracy to the hybrid method. Inclusion of expert elicitation can decrease decision uncertainty. Here, choice of method did not affect the overall cost-effectiveness conclusions, but researchers intending to use expert elicitation need to be aware of the impact different methods could have.

Value of information: interim analysis of a randomized, controlled trial of goal-directed hemodynamic treatment for aged patients.

PubMed

Bartha, Erzsebet; Davidson, Thomas; Brodtkorb, Thor-Henrik; Carlsson, Per; Kalman, Sigridur

2013-07-09

A randomized, controlled trial, intended to include 460 patients, is currently studying peroperative goal-directed hemodynamic treatment (GDHT) of aged hip-fracture patients. Interim efficacy analysis performed on the first 100 patients was statistically uncertain; thus, the trial is continuing in accordance with the trial protocol. This raised the present investigation's main question: Is it reasonable to continue to fund the trial to decrease uncertainty? To answer this question, a previously developed probabilistic cost-effectiveness model was used. That model depicts (1) a choice between routine fluid treatment and GDHT, given uncertainty of current evidence and (2) the monetary value of further data collection to decrease uncertainty. This monetary value, that is, the expected value of perfect information (EVPI), could be used to compare future research costs. Thus, the primary aim of the present investigation was to analyze EVPI of an ongoing trial with interim efficacy observed. A previously developed probabilistic decision analytic cost-effectiveness model was employed to compare the routine fluid treatment to GDHT. Results from the interim analysis, published trials, the meta-analysis, and the registry data were used as model inputs. EVPI was predicted using (1) combined uncertainty of model inputs; (2) threshold value of society's willingness to pay for one, quality-adjusted life-year; and (3) estimated number of future patients exposed to choice between GDHT and routine fluid treatment during the expected lifetime of GDHT. If a decision to use GDHT were based on cost-effectiveness, then the decision would have a substantial degree of uncertainty. Assuming a 5-year lifetime of GDHT in clinical practice, the number of patients who would be subject to future decisions was 30,400. EVPI per patient would be €204 at a €20,000 threshold value of society's willingness to pay for one quality-adjusted life-year. Given a future population of 30,400 individuals, total EVPI would be €6.19 million. If future trial costs are below EVPI, further data collection is potentially cost-effective. When applying a cost-effectiveness model, statements such as 'further research is needed' are replaced with 'further research is cost-effective and 'further funding of a trial is justified'. ClinicalTrials.gov NCT01141894.

Combining probabilistic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand

NASA Astrophysics Data System (ADS)

Sandri, Laura; Jolly, Gill; Lindsay, Jan; Howe, Tracy; Marzocchi, Warner

2010-05-01

One of the main challenges of modern volcanology is to provide the public with robust and useful information for decision-making in land-use planning and in emergency management. From the scientific point of view, this translates into reliable and quantitative long- and short-term volcanic hazard assessment and eruption forecasting. Because of the complexity in characterizing volcanic events, and of the natural variability of volcanic processes, a probabilistic approach is more suitable than deterministic modeling. In recent years, two probabilistic codes have been developed for quantitative short- and long-term eruption forecasting (BET_EF) and volcanic hazard assessment (BET_VH). Both of them are based on a Bayesian Event Tree, in which volcanic events are seen as a chain of logical steps of increasing detail. At each node of the tree, the probability is computed by taking into account different sources of information, such as geological and volcanological models, past occurrences, expert opinion and numerical modeling of volcanic phenomena. Since it is a Bayesian tool, the output probability is not a single number, but a probability distribution accounting for aleatory and epistemic uncertainty. In this study, we apply BET_VH in order to quantify the long-term volcanic hazard due to base surge invasion in the region around Auckland, New Zealand's most populous city. Here, small basaltic eruptions from monogenetic cones pose a considerable risk to the city in case of phreatomagmatic activity: evidence for base surges are not uncommon in deposits from past events. Currently, we are particularly focussing on the scenario simulated during Exercise Ruaumoko, a national disaster exercise based on the build-up to an eruption in the Auckland Volcanic Field. Based on recent papers by Marzocchi and Woo, we suggest a possible quantitative strategy to link probabilistic scientific output and Boolean decision making. It is based on cost-benefit analysis, in which all costs and benefits of mitigation actions have to be evaluated and compared, weighting them with the probability of occurrence of a specific threatening volcanic event. An action should be taken when the benefit of that action outweighs the costs. It is worth remarking that this strategy does not guarantee to recommend a decision that we would have taken with the benefit of hindsight. However, this strategy will be successful over the long-tem. Furthermore, it has the overwhelming advantage of providing a quantitative decision rule that is set before any emergency, and thus it will be justifiable at any stage of the process. In our present application, we are trying to set up a cost-benefit scheme for the call of an evacuation to protect people in the Auckland Volcanic Field against base surge invasion. Considering the heterogeneity of the urban environment and the size of the region at risk, we propose a cost-benefit scheme that is space dependent, to take into account higher costs when an eruption threatens sensible sites for the city and/or the nation, such as the international airport or the harbour. Finally, we compare our findings with the present Contingency Plan for Auckland.

Probabilistic structural analysis of aerospace components using NESSUS

NASA Technical Reports Server (NTRS)

Shiao, Michael C.; Nagpal, Vinod K.; Chamis, Christos C.

1988-01-01

Probabilistic structural analysis of a Space Shuttle main engine turbopump blade is conducted using the computer code NESSUS (numerical evaluation of stochastic structures under stress). The goal of the analysis is to derive probabilistic characteristics of blade response given probabilistic descriptions of uncertainties in blade geometry, material properties, and temperature and pressure distributions. Probability densities are derived for critical blade responses. Risk assessment and failure life analysis is conducted assuming different failure models.

Antibiotic expected effectiveness and cost under real life microbiology: evaluation of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia for elderly patients in Spain

PubMed Central

Grau, Santiago; Lozano, Virginia; Valladares, Amparo; Cavanillas, Rafael; Xie, Yang; Nocea, Gonzalo

2014-01-01

Background Clinical efficacy of antibiotics may be affected by changes in the susceptibility of microorganisms to antimicrobial agents. The purpose of this study is to assess how these changes could affect the initial efficacy of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia (CAP) in elderly patients and the potential consequences this may have in health care costs. Methods Initial efficacy in elderly was obtained from a combined analysis of two multicenter, randomized studies. An alternative scenario was carried out using initial efficacy data according to the pneumonia severity index (PSI). Country-specific pathogens distribution was obtained from a national epidemiological study, and microbiological susceptibilities to first- and second-line therapies were obtained from Spanish or European surveillance studies. A decision analytic model was used to compare ertapenem versus ceftriaxone for CAP inpatient treatment. Inputs of the model were the expected effectiveness previously estimated and resource use considering a Spanish national health system perspective. Outcomes include difference in proportion of successfully treated patients and difference in total costs between ertapenem and ceftriaxone. The model performed one-way and probabilistic sensitivity analyses. Results First-line treatment of CAP with ertapenem led to a higher proportion of successfully treated patients compared with ceftriaxone in Spain. One-way sensitivity analysis showed that length of stay was the key parameter of the model. Probabilistic sensitivity analysis showed that ertapenem can be a cost-saving strategy compared with ceftriaxone, with a 59% probability of being dominant (lower costs with additional health benefits) for both, elderly patients (>65 years) and patients with PSI >3. Conclusion The incorporation of the current antimicrobial susceptibility into the initial clinical efficacy has a significant impact in outcomes and costs in CAP treatment. The treatment with ertapenem compared with ceftriaxone resulted in better clinical outcomes and lower treatment costs for two segments of the Spanish population: elderly patients and patients with severe pneumonia (PSI >3). PMID:24611019

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: An Economic Analysis

PubMed Central

Tu, Hong Anh; Palimaka, Stefan; Sehatzadeh, Shayan; Blackhouse, Gord; Yap, Belinda; Tsoi, Bernice; Bowen, Jim; O'Reilly, Daria; Holubowich, Corinne; Kaulback, Kellee; Campbell, Kaitryn

2016-01-01

Background Major depressive disorder (MDD, 10% over a person's lifetime) is common and costly to the health system. Unfortunately, many MDD cases are resistant to treatment with antidepressant drugs and require other treatment to reduce or eliminate depression. Electroconvulsive therapy (ECT) has long been used to treat persons with treatment-resistant depression (TRD). Despite its effectiveness, ECT has side effects that make patients intolerant to the treatment, or they refuse to use it. Repetitive transcranial magnetic stimulation (rTMS), which has fewer side effects than ECT and might be an alternative for TRD patients who are ineligible for or unwilling to undergo ECT, has been developed to treat TRD. Objectives This analysis evaluates the cost-effectiveness of rTMS for patients with TRD compared with ECT or sham rTMS and estimates the potential budgetary impact of various levels of implementation of rTMS in Ontario. Review Methods A cost-utility analysis compared the costs and health outcomes of two treatments for persons with TRD in Ontario: rTMS alone compared with ECT alone and rTMS alone compared with sham rTMS. We calculated the six-month incremental costs and quality-adjusted life-years (QALYs) for these treatments. One-way and probabilistic sensitivity analyses were performed to test the robustness of the model's results. A 1-year budget impact analysis estimated the costs of providing funding for rTMS. The base-case analysis examined the additional costs for funding six centres, where rTMS infrastructure is in place. Sensitivity and scenario analyses explored the impact of increasing diffusion of rTMS to centres with existing ECT infrastructure. All analyses were conducted from the Ontario health care payer perspective. Results ECT was cost effective compared to rTMS when the willingness to pay is greater than $37,640.66 per QALY. In the base-case analysis, which had a six-month time horizon, the cost and effectiveness for rTMS was $5,272 and 0.31 quality-adjusted life-years (QALYs). The cost and effectiveness for ECT were $5,960 and 0.32 QALYs. This translates in an incremental cost-effectiveness ratio of $37,640.66 per QALY gained for ECT compared to rTMS. When rTMS is compared with sham rTMS, an additional $2,154.33 would be spent to gain 0.02 QALY. This translates to an ICER of $98,242.37 per QALY gained. Probabilistic sensitivity analysis showed that the probability of rTMS being cost-effective compared to sham rTMS was 2% and 45% at the thresholds of $50,000 and $100,000 per QALY gained, respectively. Conclusions Repetitive transcranial magnetic stimulation may be cost-effective compared to sham treatment in patients with treatment-resistant depression, depending on the willingness-to-pay threshold. PMID:27110317

THE LIQUEFACTION RISK ANALYSIS OF CEMENT-TREATED SANDY GROUND CONSIDERING THE SPATIAL VARIABILITY OF SOIL STRENGTH

NASA Astrophysics Data System (ADS)

Kataoka, Norio; Kasama, Kiyonobu; Zen, Kouki; Chen, Guangqi

This paper presents a probabilistic method for assessi ng the liquefaction risk of cement-treated ground, which is an anti-liquefaction ground improved by cemen t-mixing. In this study, the liquefaction potential of cement-treated ground is analyzed statistically using Monte Carlo Simulation based on the nonlinear earthquake response analysis consid ering the spatial variability of so il properties. The seismic bearing capacity of partially liquefied ground is analyzed in order to estimat e damage costs induced by partial liquefaction. Finally, the annual li quefaction risk is calcu lated by multiplying the liquefaction potential with the damage costs. The results indicated that the proposed new method enables to evaluate the probability of liquefaction, to estimate the damage costs using the hazard curv e, fragility curve induced by liquefaction, and liq uefaction risk curve.

Cost-Effectiveness of Pre-exposure HIV Prophylaxis During Pregnancy and Breastfeeding in Sub-Saharan Africa

PubMed Central

Wheeler, Stephanie B.; Stranix-Chibanda, Lynda; Hosek, Sybil G.; Watts, D. Heather; Siberry, George K.; Spiegel, Hans M. L.; Stringer, Jeffrey S.; Chi, Benjamin H.

2016-01-01

Introduction: Antiretroviral pre-exposure prophylaxis (PrEP) for the prevention of HIV acquisition is cost-effective when delivered to those at substantial risk. Despite a high incidence of HIV infection among pregnant and breastfeeding women in sub-Saharan Africa (SSA), a theoretical increased risk of preterm birth on PrEP could outweigh the HIV prevention benefit. Methods: We developed a decision analytic model to evaluate a strategy of daily oral PrEP during pregnancy and breastfeeding in SSA. We approached the analysis from a health care system perspective across a lifetime time horizon. Model inputs were derived from existing literature and local sources. The incremental cost-effectiveness ratio (ICER) of PrEP versus no PrEP was calculated in 2015 U.S. dollars per disability-adjusted life year (DALY) averted. We evaluated the effect of uncertainty in baseline estimates through one-way and probabilistic sensitivity analyses. Results: PrEP administered to pregnant and breastfeeding women in SSA was cost-effective. In a base case of 10,000 women, the administration of PrEP averted 381 HIV infections but resulted in 779 more preterm births. PrEP was more costly per person ($450 versus $117), but resulted in fewer disability-adjusted life years (DALYs) (3.15 versus 3.49). The incremental cost-effectiveness ratio of $965/DALY averted was below the recommended regional threshold for cost-effectiveness of $6462/DALY. Probabilistic sensitivity analyses demonstrated robustness of the model. Conclusions: Providing PrEP to pregnant and breastfeeding women in SSA is likely cost-effective, although more data are needed about adherence and safety. For populations at high risk of HIV acquisition, PrEP may be considered as part of a broader combination HIV prevention strategy. PMID:27355502

ECONOMIC AND PUBLIC HEALTH IMPACTS OF POLICIES RESTRICTING ACCESS TO HEPATITIS C TREATMENT FOR MEDICAID PATIENTS

PubMed Central

Chidi, Alexis P.; Bryce, Cindy L.; Donohue, Julie; Fine, Michael J.; Landsittel, Doug; Myaskovsky, Larissa; Rogal, Shari; Switzer, Galen; Tsung, Allan; Smith, Kenneth

2016-01-01

INTRODUCTION Interferon-free hepatitis C treatment regimens are effective but very costly. The cost-effectiveness, budget and public health impacts of current Medicaid treatment policies restricting treatment to patients with advanced disease remain unknown. METHODS Using a Markov model, we compared two strategies for 45–55 year old Medicaid beneficiaries: (1) Current Practice - only advanced disease is treated before Medicare eligibility; and (2) Full Access – both early-stage and advanced disease are treated before Medicare eligibility. Patients could develop progressive fibrosis, cirrhosis or hepatocellular carcinoma, undergo transplantation, or die each year. Morbidity was reduced after successful treatment. We calculated the incremental cost-effectiveness ratio and compared the costs and public health effects of each strategy from the perspective of Medicare alone as well as the Centers for Medicare and Medicaid Services (CMS) perspective. We varied model inputs in one-way and probabilistic sensitivity analyses. RESULTS Full Access was less costly and more effective than Current Practice for all cohorts and perspectives, with differences in cost from $5,369–$11,960 and in effectiveness from 0.82–3.01 quality adjusted life-years). In a probabilistic sensitivity analysis, Full Access was cost saving in 93% of model iterations. Compared to Current Practice, Full Access averted 5,994 hepatocellular carcinoma cases and 121 liver transplants per 100,000 patients. CONCLUSIONS Current Medicaid policies restricting hepatitis C treatment to patients with advanced disease are more costly and less effective than unrestricted, full access strategies. Collaboration between state and federal payers may be needed to realize the full public health impact of recent innovations in hepatitis C treatment. PMID:27325324

Probabilistic Structural Analysis Methods (PSAM) for select space propulsion system structural components

NASA Technical Reports Server (NTRS)

Cruse, T. A.

1987-01-01

The objective is the development of several modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as maximum stress, natural frequencies, transient response, etc. The structural analysis packages are to include stochastic modeling of loads, material properties, geometry (tolerances), and boundary conditions. The solution is to be in terms of the cumulative probability of exceedance distribution (CDF) and confidence bounds. Two methods of probability modeling are to be included as well as three types of structural models - probabilistic finite-element method (PFEM); probabilistic approximate analysis methods (PAAM); and probabilistic boundary element methods (PBEM). The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the response of a high performance structure. Probabilistic Structural Analysis Method (PSAM) tools will estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior. Perhaps most critically, the PSAM results will directly provide information on the sensitivity of the design response to those variables which are seen to be uncertain.

Probabilistic Structural Analysis Methods for select space propulsion system structural components (PSAM)

NASA Technical Reports Server (NTRS)

Cruse, T. A.; Burnside, O. H.; Wu, Y.-T.; Polch, E. Z.; Dias, J. B.

1988-01-01

The objective is the development of several modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as maximum stress, natural frequencies, transient response, etc. The structural analysis packages are to include stochastic modeling of loads, material properties, geometry (tolerances), and boundary conditions. The solution is to be in terms of the cumulative probability of exceedance distribution (CDF) and confidence bounds. Two methods of probability modeling are to be included as well as three types of structural models - probabilistic finite-element method (PFEM); probabilistic approximate analysis methods (PAAM); and probabilistic boundary element methods (PBEM). The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the response of a high performance structure. Probabilistic Structural Analysis Method (PSAM) tools will estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior. Perhaps most critically, the PSAM results will directly provide information on the sensitivity of the design response to those variables which are seen to be uncertain.

Probabilistic Structural Analysis of the Solid Rocket Booster Aft Skirt External Fitting Modification

NASA Technical Reports Server (NTRS)

Townsend, John S.; Peck, Jeff; Ayala, Samuel

2000-01-01

NASA has funded several major programs (the Probabilistic Structural Analysis Methods Project is an example) to develop probabilistic structural analysis methods and tools for engineers to apply in the design and assessment of aerospace hardware. A probabilistic finite element software code, known as Numerical Evaluation of Stochastic Structures Under Stress, is used to determine the reliability of a critical weld of the Space Shuttle solid rocket booster aft skirt. An external bracket modification to the aft skirt provides a comparison basis for examining the details of the probabilistic analysis and its contributions to the design process. Also, analysis findings are compared with measured Space Shuttle flight data.

Surgical management of bilateral vocal fold paralysis: A cost-effectiveness comparison of two treatments.

PubMed

Naunheim, Matthew R; Song, Phillip C; Franco, Ramon A; Alkire, Blake C; Shrime, Mark G

2017-03-01

Endoscopic management of bilateral vocal fold paralysis (BVFP) includes cordotomy and arytenoidectomy, and has become a well-accepted alternative to tracheostomy. However, the costs and quality-of-life benefits of endoscopic management have not been examined with formal economic analysis. This study undertakes a cost-effectiveness analysis of tracheostomy versus endoscopic management of BVFP. Cost-effectiveness analysis. A literature review identified a range of costs and outcomes associated with surgical options for BVFP. Additional costs were derived from Medicare reimbursement data; all were adjusted to 2014 dollars. Cost-effectiveness analysis evaluated both therapeutic strategies in short-term and long-term scenarios. Probabilistic sensitivity analysis was used to assess confidence levels regarding the economic evaluation. The incremental cost effectiveness ratio for endoscopic management versus tracheostomy is $31,600.06 per quality-adjusted life year (QALY), indicating that endoscopic management is the cost-effective short-term strategy at a willingness-to-pay (WTP) threshold of $50,000/QALY. The probability that endoscopic management is more cost-effective than tracheostomy at this WTP is 65.1%. Threshold analysis demonstrated that the model is sensitive to both utilities and cost in the short-term scenario. When costs of long-term care are included, tracheostomy is dominated by endoscopic management, indicating the cost-effectiveness of endoscopic management at any WTP. Endoscopic management of BVFP appears to be more cost-effective than tracheostomy. Though endoscopic cordotomy and arytenoidectomy require expertise and specialized equipment, this model demonstrates utility gains and long-term cost advantages to an endoscopic strategy. These findings are limited by the relative paucity of robust utility data and emphasize the need for further economic analysis in otolaryngology. NA Laryngoscope, 127:691-697, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

[Cost-effectiveness of two hospital care schemes for psychiatric disorders].

PubMed

Nevárez-Sida, Armando; Valencia-Huarte, Enrique; Escobedo-Islas, Octavio; Constantino-Casas, Patricia; Verduzco-Fragoso, Wázcar; León-González, Guillermo

2013-01-01

In Mexico, six of every twenty Mexicans suffer psychiatric disorders at some time in their lives. This disease ranks fifth in the country. The objective was to determine and compare the cost-effectiveness of two models for hospital care (partial and traditional) at a psychiatric hospital of Instituto Mexicano del Seguro Social (IMSS). a multicenter study with a prospective cohort of 374 patients was performed. We made a cost-effectiveness analysis from an institutional viewpoint with a six-month follow-up. Direct medical costs were analyzed, with quality of life gains as outcome measurement. A decision tree and a probabilistic sensitivity analysis were used. patient care in the partial model had a cost 50 % lower than the traditional one, with similar results in quality of life. The cost per successful unit in partial hospitalization was 3359 Mexican pesos while in the traditional it increased to 5470 Mexican pesos. treating patients in the partial hospitalization model is a cost-effective alternative compared with the traditional model. Therefore, the IMSS should promote the infrastructure that delivers the psychiatric services to the patient attending to who requires it.

Stochastic model for fatigue crack size and cost effective design decisions. [for aerospace structures

NASA Technical Reports Server (NTRS)

Hanagud, S.; Uppaluri, B.

1975-01-01

This paper describes a methodology for making cost effective fatigue design decisions. The methodology is based on a probabilistic model for the stochastic process of fatigue crack growth with time. The development of a particular model for the stochastic process is also discussed in the paper. The model is based on the assumption of continuous time and discrete space of crack lengths. Statistical decision theory and the developed probabilistic model are used to develop the procedure for making fatigue design decisions on the basis of minimum expected cost or risk function and reliability bounds. Selections of initial flaw size distribution, NDT, repair threshold crack lengths, and inspection intervals are discussed.

Cost effectiveness of population based BRCA1 founder mutation testing in Sephardi Jewish women.

PubMed

Patel, Shreeya; Legood, Rosa; Evans, D Gareth; Turnbull, Clare; Antoniou, Antonis C; Menon, Usha; Jacobs, Ian; Manchanda, Ranjit

2018-04-01

Population-based BRCA1/BRCA2 founder-mutation testing has been demonstrated as cost effective compared with family history based testing in Ashkenazi Jewish women. However, only 1 of the 3 Ashkenazi Jewish BRCA1/BRCA2 founder mutations (185delAG[c.68_69delAG]), 5382insC[c.5266dupC]), and 6174delT[c.5946delT]) is found in the Sephardi Jewish population (185delAG[c.68_69delAG]), and the overall prevalence of BRCA mutations in the Sephardi Jewish population is accordingly lower (0.7% compared with 2.5% in the Ashkenazi Jewish population). Cost-effectiveness analyses of BRCA testing have not previously been performed at these lower BRCA prevalence levels seen in the Sephardi Jewish population. Here we present a cost-effectiveness analysis for UK and US populations comparing population testing with clinical criteria/family history-based testing in Sephardi Jewish women. A Markov model was built comparing the lifetime costs and effects of population-based BRCA1 testing, with testing using family history-based clinical criteria in Sephardi Jewish women aged ≥30 years. BRCA1 carriers identified were offered magnetic resonance imaging/mammograms and risk-reducing surgery. Costs are reported at 2015 prices. Outcomes include breast cancer, ovarian cancer, and excess deaths from heart disease. All costs and outcomes are discounted at 3.5%. The time horizon is lifetime, and perspective is payer. The incremental cost-effectiveness ratio per quality-adjusted life-year was calculated. Parameter uncertainty was evaluated through 1-way and probabilistic sensitivity analysis. Population testing resulted in gain in life expectancy of 12 months (quality-adjusted life-year = 1.00). The baseline discounted incremental cost-effectiveness ratio for UK population-based testing was £67.04/quality-adjusted life-year and for US population was $308.42/quality-adjusted life-year. Results were robust in the 1-way sensitivity analysis. The probabilistic sensitivity analysis showed 100% of simulations were cost effective at £20,000/quality-adjusted life-year UK and the $100,000/quality-adjusted life-year US willingness-to-pay thresholds. Scenario analysis showed that population testing remains cost effective in UK and US populations, even if premenopausal oophorectomy does not reduce breast cancer risk or if hormone replacement therapy compliance is nil. Population-based BRCA1 testing is highly cost effective compared with clinical criteria-driven approach in Sephardi Jewish women. This supports changing the paradigm to population-based BRCA testing in the Jewish population, regardless of Ashkenazi/Sephardi ancestry. Copyright © 2017 Elsevier Inc. All rights reserved.

Cost-minimization analysis favours intravenous ferric carboxymaltose over ferric sucrose or oral iron as preoperative treatment in patients with colon cancer and iron deficiency anaemia.

PubMed

Calvet, Xavier; Gené, Emili; ÀngelRuíz, Miquel; Figuerola, Ariadna; Villoria, Albert; Cucala, Mercedes; Mearin, Fermín; Delgado, Salvadora; Calleja, Jose Luis

2016-01-01

Ferric Carboxymaltose (FCM), Iron Sucrose (IS) and Oral Iron (OI) are alternative treatments for preoperative anaemia. To compare the cost implications, using a cost-minimization analysis, of three alternatives: FCM vs. IS vs. OI for treating iron-deficient anaemia before surgery in patients with colon cancer. Data from 282 patients with colorectal cancer and anaemia were obtained from a previous study. One hundred and eleven received FCS, 16 IS and 155 OI. Costs of intravenous iron drugs were obtained from the Spanish Regulatory Agency. Direct and indirect costs were obtained from the analytical accounting unit of the Hospital. In the base case mean costs per patient were calculated. Sensitivity analysis and probabilistic Monte Carlo simulation were performed. Total costs per patient were 1827® in the FCM group, 2312® in the IS group and 2101® in the OI group. Cost savings per patient for FCM treatment were 485® compared to IS and 274® compared to OI. A Monte Carlo simulation favoured the use of FCM in 84.7% and 84.4% of simulations when compared to IS and OI, respectively. FCM infusion before surgery reduced costs in patients with colon cancer and iron-deficiency anaemia when compared with OI and IS.

Cost utility analysis of endoscopic biliary stent in unresectable hilar cholangiocarcinoma: decision analytic modeling approach.

PubMed

Sangchan, Apichat; Chaiyakunapruk, Nathorn; Supakankunti, Siripen; Pugkhem, Ake; Mairiang, Pisaln

2014-01-01

Endoscopic biliary drainage using metal and plastic stent in unresectable hilar cholangiocarcinoma (HCA) is widely used but little is known about their cost-effectiveness. This study evaluated the cost-utility of endoscopic metal and plastic stent drainage in unresectable complex, Bismuth type II-IV, HCA patients. Decision analytic model, Markov model, was used to evaluate cost and quality-adjusted life year (QALY) of endoscopic biliary drainage in unresectable HCA. Costs of treatment and utilities of each Markov state were retrieved from hospital charges and unresectable HCA patients from tertiary care hospital in Thailand, respectively. Transition probabilities were derived from international literature. Base case analyses and sensitivity analyses were performed. Under the base-case analysis, metal stent is more effective but more expensive than plastic stent. An incremental cost per additional QALY gained is 192,650 baht (US$ 6,318). From probabilistic sensitivity analysis, at the willingness to pay threshold of one and three times GDP per capita or 158,000 baht (US$ 5,182) and 474,000 baht (US$ 15,546), the probability of metal stent being cost-effective is 26.4% and 99.8%, respectively. Based on the WHO recommendation regarding the cost-effectiveness threshold criteria, endoscopic metal stent drainage is cost-effective compared to plastic stent in unresectable complex HCA.

A Probabilistic Collocation Based Iterative Kalman Filter for Landfill Data Assimilation

NASA Astrophysics Data System (ADS)

Qiang, Z.; Zeng, L.; Wu, L.

2016-12-01

Due to the strong spatial heterogeneity of landfill, uncertainty is ubiquitous in gas transport process in landfill. To accurately characterize the landfill properties, the ensemble Kalman filter (EnKF) has been employed to assimilate the measurements, e.g., the gas pressure. As a Monte Carlo (MC) based method, the EnKF usually requires a large ensemble size, which poses a high computational cost for large scale problems. In this work, we propose a probabilistic collocation based iterative Kalman filter (PCIKF) to estimate permeability in a liquid-gas coupling model. This method employs polynomial chaos expansion (PCE) to represent and propagate the uncertainties of model parameters and states, and an iterative form of Kalman filter to assimilate the current gas pressure data. To further reduce the computation cost, the functional ANOVA (analysis of variance) decomposition is conducted, and only the first order ANOVA components are remained for PCE. Illustrated with numerical case studies, this proposed method shows significant superiority in computation efficiency compared with the traditional MC based iterative EnKF. The developed method has promising potential in reliable prediction and management of landfill gas production.

Determination of Economic Lot Size between Suppliers and Manufacturers for Imperfect Production System with Probabilistic Demand

NASA Astrophysics Data System (ADS)

Yuniar, S.; Wangsaputra, R.; Sinaga, A. T.

2018-03-01

This study aims to develop a combined economical lot size model between supplier and manufacturer for imperfect production processes with probabilistic demand patterns and constant lead times. The supplier side produces the product within a certain time interval then sent to the manufacturer with a certain amount of lot size. Imperfect supplier production systems are characterized by the probability of defective product (γ). The model decision variables are the lot size of the manufacturer's ordering, supplier lot size, and the reorder point of the manufacturer. The optimal decision variables are obtained by minimizing the total expected cost of the combined costs between the suppliers and the manufacturers borne by both parties. The model is built compared to the transactional partnership model, in which the supplier does not participate in the efficiency of its inventory system. A numerical example is given as an illustration of the JELS model and the transactional partnership model. Sensitivity analysis of the model is done by changing the parameters aimed at analyzing the behavior of the developed model.

Optimal design of groundwater remediation system using a probabilistic multi-objective fast harmony search algorithm under uncertainty

NASA Astrophysics Data System (ADS)

Luo, Qiankun; Wu, Jianfeng; Yang, Yun; Qian, Jiazhong; Wu, Jichun

2014-11-01

This study develops a new probabilistic multi-objective fast harmony search algorithm (PMOFHS) for optimal design of groundwater remediation systems under uncertainty associated with the hydraulic conductivity (K) of aquifers. The PMOFHS integrates the previously developed deterministic multi-objective optimization method, namely multi-objective fast harmony search algorithm (MOFHS) with a probabilistic sorting technique to search for Pareto-optimal solutions to multi-objective optimization problems in a noisy hydrogeological environment arising from insufficient K data. The PMOFHS is then coupled with the commonly used flow and transport codes, MODFLOW and MT3DMS, to identify the optimal design of groundwater remediation systems for a two-dimensional hypothetical test problem and a three-dimensional Indiana field application involving two objectives: (i) minimization of the total remediation cost through the engineering planning horizon, and (ii) minimization of the mass remaining in the aquifer at the end of the operational period, whereby the pump-and-treat (PAT) technology is used to clean up contaminated groundwater. Also, Monte Carlo (MC) analysis is employed to evaluate the effectiveness of the proposed methodology. Comprehensive analysis indicates that the proposed PMOFHS can find Pareto-optimal solutions with low variability and high reliability and is a potentially effective tool for optimizing multi-objective groundwater remediation problems under uncertainty.

Cost-Effectiveness of Ribociclib plus Letrozole Versus Palbociclib plus Letrozole and Letrozole Monotherapy in the First-Line Treatment of Postmenopausal Women with HR+/HER2- Advanced or Metastatic Breast Cancer: A U.S. Payer Perspective.

PubMed

Mistry, Rohit; May, Jessica R; Suri, Gaurav; Young, Kate; Brixner, Diana; Oderda, Gary; Biskupiak, Joseph; Tang, Derek; Bhattacharyya, Subrata; Mishra, Dinesh; Bhattacharyya, Devarshi; Dalal, Anand A

2018-06-01

U.S. regulatory approvals of the cyclin-dependent kinase 4 and 6 (CDK 4/6) inhibitors ribociclib and palbociclib as add-ons to letrozole greatly enhance the prospects for treating postmenopausal women with hormone receptor-positive (HR+)/human epidermal receptor 2-negative (HER2-) advanced or metastatic breast cancer. Clinical trials have established that the combination of a CDK 4/6 inhibitor with letrozole can significantly improve progression-free survival (PFS) versus letrozole monotherapy and is safe and well tolerated. Cost-effectiveness studies are required to inform payers and clinical decision makers on the money value of combination treatment in clinical practice. To evaluate the cost-effectiveness of ribociclib plus letrozole versus palbociclib plus letrozole and versus letrozole monotherapy in the first-line treatment of postmenopausal women with HR+/HER2- advanced or metastatic breast cancer from a U.S. private third-party payer perspective. A partitioned survival model including 3 health states (progression free, with either overall response or stable disease; progressed disease; and death) simulated lifetime costs and outcomes over a 40-year lifetime horizon with a 1-month cycle length. Clinical efficacy data (PFS and overall survival [OS]) were derived from a phase III trial of ribociclib plus letrozole (MONALEESA-2; NCT01958021), a phase II trial of palbociclib plus letrozole (PALOMA-1; NCT00721409), and a Bayesian network meta-analysis. Health care costs included drug acquisition and monitoring, disease management, subsequent therapies, and serious drug-related adverse events. Effectiveness was measured in life-years, derived from survival projections, and in quality-adjusted life-years (QALYs), calculated from time spent in each state combined with health-state utility values. A one-way deterministic sensitivity analysis explored the impact of uncertainty in key model parameters on results, and probabilistic uncertainty was assessed through a Monte Carlo probabilistic sensitivity analysis. Ribociclib plus letrozole was dominant versus palbociclib plus letrozole, with a cost saving of $43,037 and a gain of 0.086 QALYs. Compared with letrozole monotherapy, ribociclib plus letrozole was associated with an incremental cost of $144,915 and an incremental QALY of 0.689, equating to an incremental cost-effectiveness ratio of $210,369 per QALY. Key model drivers included OS HRs for palbociclib plus letrozole versus letrozole and for ribociclib plus letrozole versus letrozole, the PFS HR for palbociclib plus letrozole versus letrozole, PD health-state costs, utility of response, and cost discount rate. The probabilities that ribociclib plus letrozole was cost-effective versus letrozole at thresholds of $50,000, $100,000 and $200,000 per QALY gained were 1.6%, 6.3%, and 50.5%, respectively. In the United States, ribociclib plus letrozole is a cost-effective alternative to palbociclib plus letrozole for the first-line treatment of postmenopausal women with HR+/HER2- advanced or metastatic breast cancer. Ribociclib plus letrozole is also cost-effective versus letrozole monotherapy at willingness-to-pay thresholds greater than $198,000 per QALY (for probabilistic analysis). Funding for this study was provided by Novartis, which manufactures ribociclib and provided input on the study design and data collection, analysis, and interpretation. Mistry, May, Suri, and Young are employees of PAREXEL. Tang, Mishra, D. Bhattacharyya, and Dalal are employees of Novartis. S. Bhattacharyya was an employee of Novartis during the study period. Tang and Dalal hold stock in Novartis. Brixner, Oderda, and Biskupiak were paid by Millcreek Outcomes Group as consultants for work on this project. Brixner has also consulted for AstraZeneca, UCB, Regeneron, and Abbott.

Cost–Utility of Angiotensin-Converting Enzyme Inhibitor-Based Treatment Compared With Thiazide Diuretic-Based Treatment for Hypertension in Elderly Australians Considering Diabetes as Comorbidity

PubMed Central

Chowdhury, Enayet K.; Ademi, Zanfina; Moss, John R.; Wing, Lindon M.H.; Reid, Christopher M.

2015-01-01

Abstract The objective of this study was to examine the cost-effectiveness of angiotensin-converting enzyme inhibitor (ACEI)-based treatment compared with thiazide diuretic-based treatment for hypertension in elderly Australians considering diabetes as an outcome along with cardiovascular outcomes from the Australian government's perspective. We used a cost–utility analysis to estimate the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained. Data on cardiovascular events and new onset of diabetes were used from the Second Australian National Blood Pressure Study, a randomized clinical trial comparing diuretic-based (hydrochlorothiazide) versus ACEI-based (enalapril) treatment in 6083 elderly (age ≥65 years) hypertensive patients over a median 4.1-year period. For this economic analysis, the total study population was stratified into 2 groups. Group A was restricted to participants diabetes free at baseline (n = 5642); group B was restricted to participants with preexisting diabetes mellitus (type 1 or type 2) at baseline (n = 441). Data on utility scores for different events were used from available published literatures; whereas, treatment and adverse event management costs were calculated from direct health care costs available from Australian government reimbursement data. Costs and QALYs were discounted at 5% per annum. One-way and probabilistic sensitivity analyses were performed to assess the uncertainty around utilities and cost data. After a treatment period of 5 years, for group A, the ICER was Australian dollars (AUD) 27,698 (€ 18,004; AUD 1–€ 0.65) per QALY gained comparing ACEI-based treatment with diuretic-based treatment (sensitive to the utility value for new-onset diabetes). In group B, ACEI-based treatment was a dominant strategy (both more effective and cost-saving). On probabilistic sensitivity analysis, the ICERs per QALY gained were always below AUD 50,000 for group B; whereas for group A, the probability of being below AUD 50,000 was 85%. Although the dispensed price of diuretic-based treatment of hypertension in the elderly is lower, upon considering the potential enhanced likelihood of the development of diabetes in addition to the costs of treating cardiovascular disease, ACEI-based treatment may be a more cost-effective strategy in this population. PMID:25738481

Cost-effectiveness of rosuvastatin for primary prevention of cardiovascular events according to Framingham Risk Score in patients with elevated C-reactive protein.

PubMed

MacDonald, Gary P

2010-08-01

The Food and Drug Administration (FDA) recently approved rosuvastatin calcium for prevention of cardiovascular events in patients who have elevated levels of high-sensitivity C-reactive protein (hs-CRP) but not overt hyperlipidemia. The FDA's decision was based primarily on research reported by the JUPITER (Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin) Study Group. The cost-effectiveness of such treatment is unknown. To compare the cost-effectiveness of treatment with rosuvastatin vs standard management, according to Framingham Risk Score (FRS), for the primary prevention of cardiovascular events in patients who have hs-CRP levels of 2.0 mg/L or higher and low-density lipoprotein cholesterol (LDL-C) levels of less than 130 mg/dL. A Markov-type model was used to calculate the incremental cost-effectiveness ratio of rosuvastatin (20 mg daily) vs standard management for the primary prevention of cardiovascular events in patients over a 10-year period. Cost data were obtained from the Centers for Medicare & Medicaid Services and the Red Book drug reference. Health utility measures were obtained from the literature. Cardiovascular event data were obtained directly from the JUPITER Study Group. One-way sensitivity analysis and probabilistic sensitivity analysis were conducted. Treating patients with rosuvastatin to prevent cardiovascular events based on a hs-CRP level greater than 2.0 mg/L and an LDL-C level of 130 mg/dL or lower would result in estimated incremental cost-effectiveness ratios of $35,455 per quality-adjusted life year (QALY) in patients with an FRS greater than 10% and $90,714 per QALY in patients with an FRS less than or equal to 10%. Results of probabilistic sensitivity analysis suggested that in patients with an FRS greater than 10%, the probability that rosuvastatin is considered cost-effective at $50,000 per QALY is approximately 98%. In patients with an FRS less than or equal to 10%, the probability that rosuvastatin is considered cost-effective at $50,000 per QALY is 0%. Compared with standard management, treatment with rosuvastatin is a cost-effective strategy over a 10-year period for preventing cardiovascular events in patients with FRS greater than 10%, elevated hs-CRP levels, and normal LDL-C levels.

Comparative life cycle cost assessment of painted and hot-dip galvanized bridges.

PubMed

Rossi, B; Marquart, S; Rossi, G

2017-07-15

The study addresses the life cycle cost assessment (LCCA) of steel bridges, focusing on the maintenance activities and the maintenance scenario. Firstly, the unit costs of maintenance activities and their durability (i.e. the time between two activities) are evaluated. Pragmatic data are provided for the environment category C4 and for three activities: Patch Up, Overcoating and Remove & Replace. A comparative LCCA for a typical hypothetic steel girder bridge is carried out, either painted or hot-dip galvanized (HDG), in the environmental class C4. The LCC versus the cumulated life is provided for both options. The initial cost of the steel unpainted option is only 50.3% of the HDG option. It is shown that after 'Overcoating' occurring at 18.5 years, the total Net Present Value (NPV) of the painted option surpasses that of the HDG option. A sensitivity analysis of the NPV to the cost and service life parameters, the escalation and discount rates is then performed. The discount and escalation rates, considerably influences the total LCC, following a non-linear trend. The total LCC decreases with the discount rate increasing and, conversely, increases with the escalation rate increasing. Secondly, the influence of the maintenance scenario on the total LCC is assessed based on a probabilistic approach. A permutation of the three independent maintenance activities assumed to occur six times over the life of the bridge is considered and a probability of occurrence is associated to each unique scenario. The most probable scenarios are then classified according to their NPV or achieved service life. This approach leads to the definition of a cost-effective maintenance scenario i.e. the scenario, within all the considered permutations, that has the minimum LCC in a range of lifespan. Besides, the probabilistic analysis also shows that, whatever the scenario, the return on investment period ranges between 18.5 years and 24.2 years. After that period, the HDG option becomes economic. Copyright © 2017 Elsevier Ltd. All rights reserved.

Everolimus plus exemestane versus bevacizumab-based chemotherapy for second-line treatment of hormone receptor-positive metastatic breast cancer in Greece: An economic evaluation study.

PubMed

Kourlaba, Georgia; Rapti, Vasiliki; Alexopoulos, Athanasios; Relakis, John; Koumakis, Georgios; Chatzikou, Magdalini; Maniadakis, Nikos; Georgoulias, Vassilis

2015-08-05

The objective of our study was to conduct a cost-effectiveness (CE) study of combined everolimus (EVE) and exemestane (EXE) versus the common clinical practice in Greece for the treatment of postmenopausal women with HR+/HER2- advanced breast cancer (BC) progressing on nonsteroidal aromatase inhibitors (NSAI). The combinations of bevacizumab (BEV) plus paclitaxel (PACL) and BEV plus capecitabine (CAPE) were selected as comparators. A Markov model, consisting of three health states, was used to describe disease progression and evaluate the CE of the comparators from a third-party payer perspective over a lifetime horizon. Efficacy and safety data as well as utility values considered in the model were extracted from the relevant randomized Phase III clinical trials and other published studies. Direct medical costs referring to the year 2014 were incorporated in the model. A probabilistic sensitivity analysis was conducted to account for uncertainty and variation in the parameters of the model. Primary outcomes were patient survival (life-years), quality-adjusted life years (QALYs), total direct costs and incremental cost-effectiveness ratios (ICER). The discounted quality-adjusted survival of patients treated with EVE plus EXE was greater by 0.035 and 0.004 QALYs, compared to BEV plus PACL and BEV plus CAPE, respectively. EVE plus EXE was the least costly treatment in terms of drug acquisition, administration, and concomitant medications. The total lifetime cost per patient was estimated at €55,022, €67,980, and €62,822 for EVE plus EXE, BEV plus PACL, and BEV plus CAPE, respectively. The probabilistic analysis confirmed the deterministic results. Our results suggest that EVE plus EXE may be a dominant alternative relative to BEV plus PACL and BEV plus CAPE for the treatment of HR+/HER2- advanced BC patients failing initial therapy with NSAIs.

Application of the probabilistic approximate analysis method to a turbopump blade analysis. [for Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Thacker, B. H.; Mcclung, R. C.; Millwater, H. R.

1990-01-01

An eigenvalue analysis of a typical space propulsion system turbopump blade is presented using an approximate probabilistic analysis methodology. The methodology was developed originally to investigate the feasibility of computing probabilistic structural response using closed-form approximate models. This paper extends the methodology to structures for which simple closed-form solutions do not exist. The finite element method will be used for this demonstration, but the concepts apply to any numerical method. The results agree with detailed analysis results and indicate the usefulness of using a probabilistic approximate analysis in determining efficient solution strategies.

A look-ahead probabilistic contingency analysis framework incorporating smart sampling techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yousu; Etingov, Pavel V.; Ren, Huiying

2016-07-18

This paper describes a framework of incorporating smart sampling techniques in a probabilistic look-ahead contingency analysis application. The predictive probabilistic contingency analysis helps to reflect the impact of uncertainties caused by variable generation and load on potential violations of transmission limits.

The analysis of cost-effectiveness of implant and conventional fixed dental prosthesis.

PubMed

Chun, June Sang; Har, Alix; Lim, Hyun-Pil; Lim, Hoi-Jeong

2016-02-01

This study conducted an analysis of cost-effectiveness of the implant and conventional fixed dental prosthesis (CFDP) from a single treatment perspective. The Markov model for cost-effectiveness analysis of the implant and CFDP was carried out over maximum 50 years. The probabilistic sensitivity analysis was performed by the 10,000 Monte-Carlo simulations, and cost-effectiveness acceptability curves (CEAC) were also presented. The results from meta-analysis studies were used to determine the survival rates and complication rates of the implant and CFDP. Data regarding the cost of each treatment method were collected from University Dental Hospital and Statistics Korea for 2013. Using the results of the patient satisfaction survey study, quality-adjusted prosthesis year (QAPY) of the implant and CFDP strategy was evaluated with annual discount rate. When only the direct cost was considered, implants were more cost-effective when the willingness to pay (WTP) was more than 10,000 won at 10(th) year after the treatment, and more cost-effective regardless of the WTP from 20(th) year after the prosthodontic treatment. When the indirect cost was added to the direct cost, implants were more cost-effective only when the WTP was more than 75,000 won at the 10(th) year after the prosthodontic treatment, more than 35,000 won at the 20(th) year after prosthodontic treatment. The CFDP was more cost-effective unless the WTP was more than 75,000 won at the 10(th) year after prosthodontic treatment. But the cost-effectivenss tendency changed from CFDP to implant as time passed.

Probabilistic structural analysis methods of hot engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hopkins, D. A.

1989-01-01

Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. Recent activities have focused on extending the methods to include the combined uncertainties in several factors on structural response. This paper briefly describes recent progress on composite load spectra models, probabilistic finite element structural analysis, and probabilistic strength degradation modeling. Progress is described in terms of fundamental concepts, computer code development, and representative numerical results.

Probabilistic Design Storm Method for Improved Flood Estimation in Ungauged Catchments

NASA Astrophysics Data System (ADS)

Berk, Mario; Å pačková, Olga; Straub, Daniel

2017-12-01

The design storm approach with event-based rainfall-runoff models is a standard method for design flood estimation in ungauged catchments. The approach is conceptually simple and computationally inexpensive, but the underlying assumptions can lead to flawed design flood estimations. In particular, the implied average recurrence interval (ARI) neutrality between rainfall and runoff neglects uncertainty in other important parameters, leading to an underestimation of design floods. The selection of a single representative critical rainfall duration in the analysis leads to an additional underestimation of design floods. One way to overcome these nonconservative approximations is the use of a continuous rainfall-runoff model, which is associated with significant computational cost and requires rainfall input data that are often not readily available. As an alternative, we propose a novel Probabilistic Design Storm method that combines event-based flood modeling with basic probabilistic models and concepts from reliability analysis, in particular the First-Order Reliability Method (FORM). The proposed methodology overcomes the limitations of the standard design storm approach, while utilizing the same input information and models without excessive computational effort. Additionally, the Probabilistic Design Storm method allows deriving so-called design charts, which summarize representative design storm events (combinations of rainfall intensity and other relevant parameters) for floods with different return periods. These can be used to study the relationship between rainfall and runoff return periods. We demonstrate, investigate, and validate the method by means of an example catchment located in the Bavarian Pre-Alps, in combination with a simple hydrological model commonly used in practice.

75 FR 13610 - Office of New Reactors; Interim Staff Guidance on Implementation of a Seismic Margin Analysis for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

... Staff Guidance on Implementation of a Seismic Margin Analysis for New Reactors Based on Probabilistic... Seismic Margin Analysis for New Reactors Based on Probabilistic Risk Assessment,'' (Agencywide Documents.../COL-ISG-020 ``Implementation of a Seismic Margin Analysis for New Reactors Based on Probabilistic Risk...

Cost-utility and budget impact analysis of drug treatments in pulmonary arterial hypertension associated with congenital heart diseases in Thailand.

PubMed

Thongsri, Watsamon; Bussabawalai, Thanaporn; Leelahavarong, Pattara; Wanitkun, Suthep; Durongpisitkul, Kritvikrom; Chaikledkaew, Usa; Teerawattananon, Yot

2016-08-01

This study aims to compare the lifetime costs and health outcomes of both first-line and sequential combination treatments with standard treatment for pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD) (PAH-CHD) patients. A cost-utility analysis was performed using a Markov model based on a societal perspective. One-way and probabilistic sensitivity analyses were performed to investigate the effect of parameter uncertainty. As first-line treatments, both beraprost (incremental cost-effectiveness ratio (ICER) = 192,752 and 201,308 Thai baht (THB) per quality-adjusted life year (QALY) gained) and sildenafil (ICER = 249,770 and 226,802 THB per QALY gained) seemed cost-effective for PAH-CHD patients aged ≤30 years in functional classes II and III, respectively, while no treatment was cost-effective for the sequential combination therapy. Sildenafil should be included in the National Drug List of Essential Medicines as the first-line treatment for PAH-CHD, and its price per dose should be negotiated to be reduced by 43-57%.

The cost-effectiveness of the Olweus Bullying Prevention Program: Results from a modelling study.

PubMed

Beckman, Linda; Svensson, Mikael

2015-12-01

Exposure to bullying affects around 3-5 percent of adolescents in secondary school and is related to various mental health problems. Many different anti-bullying programmes are currently available, but economic evaluations are lacking. The aim of this study is to identify the cost effectiveness of the Olweus Bullying Prevention Program (OBPP). We constructed a decision-tree model for a Swedish secondary school, using a public payer perspective, and retrieved data on costs and effects from the published literature. Probabilistic sensitivity analysis to reflect the uncertainty in the model was conducted. The base-case analysis showed that using the OBPP to reduce the number of victims of bullying costs 131,250 Swedish kronor (€14,470) per victim spared. Compared to a relevant threshold of the societal value of bullying reduction, this indicates that the programme is cost-effective. Using a relevant willingness-to-pay threshold shows that the OBPP is a cost-effective intervention. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Robotic Versus Open Renal Transplantation in Obese Patients: Protocol for a Cost-Benefit Markov Model Analysis

PubMed Central

Puttarajappa, Chethan; Wijkstrom, Martin; Ganoza, Armando; Lopez, Roberto; Tevar, Amit

2018-01-01

Background Recent studies have reported a significant decrease in wound problems and hospital stay in obese patients undergoing renal transplantation by robotic-assisted minimally invasive techniques with no difference in graft function. Objective Due to the lack of cost-benefit studies on the use of robotic-assisted renal transplantation versus open surgical procedure, the primary aim of our study is to develop a Markov model to analyze the cost-benefit of robotic surgery versus open traditional surgery in obese patients in need of a renal transplant. Methods Electronic searches will be conducted to identify studies comparing open renal transplantation versus robotic-assisted renal transplantation. Costs associated with the two surgical techniques will incorporate the expenses of the resources used for the operations. A decision analysis model will be developed to simulate a randomized controlled trial comparing three interventional arms: (1) continuation of renal replacement therapy for patients who are considered non-suitable candidates for renal transplantation due to obesity, (2) transplant recipients undergoing open transplant surgery, and (3) transplant patients undergoing robotic-assisted renal transplantation. TreeAge Pro 2017 R1 TreeAge Software, Williamstown, MA, USA) will be used to create a Markov model and microsimulation will be used to compare costs and benefits for the two competing surgical interventions. Results The model will simulate a randomized controlled trial of adult obese patients affected by end-stage renal disease undergoing renal transplantation. The absorbing state of the model will be patients' death from any cause. By choosing death as the absorbing state, we will be able simulate the population of renal transplant recipients from the day of their randomization to transplant surgery or continuation on renal replacement therapy to their death and perform sensitivity analysis around patients' age at the time of randomization to determine if age is a critical variable for cost-benefit analysis or cost-effectiveness analysis comparing renal replacement therapy, robotic-assisted surgery or open renal transplant surgery. After running the model, one of the three competing strategies will result as the most cost-beneficial or cost-effective under common circumstances. To assess the robustness of the results of the model, a multivariable probabilistic sensitivity analysis will be performed by modifying the mean values and confidence intervals of key parameters with the main intent of assessing if the winning strategy is sensitive to rigorous and plausible variations of those values. Conclusions After running the model, one of the three competing strategies will result as the most cost-beneficial or cost-effective under common circumstances. To assess the robustness of the results of the model, a multivariable probabilistic sensitivity analysis will be performed by modifying the mean values and confidence intervals of key parameters with the main intent of assessing if the winning strategy is sensitive to rigorous and plausible variations of those values. PMID:29519780

A cost-effectiveness evaluation of hospital discharge counseling by pharmacists.

PubMed

Chinthammit, Chanadda; Armstrong, Edward P; Warholak, Terri L

2012-04-01

This study estimated the cost-effectiveness of pharmacist discharge counseling on medication-related morbidity in both the high-risk elderly and general US population. A cost-effectiveness decision analytic model was developed using a health care system perspective based on published clinical trials. Costs included direct medical costs, and the effectiveness unit was patients discharged without suffering a subsequent adverse drug event. A systematic review of published studies was conducted to estimate variable probabilities in the cost-effectiveness model. To test the robustness of the results, a second-order probabilistic sensitivity analysis (Monte Carlo simulation) was used to run 10 000 cases through the model sampling across all distributions simultaneously. Pharmacist counseling at hospital discharge provided a small, but statistically significant, clinical improvement at a similar overall cost. Pharmacist counseling was cost saving in approximately 48% of scenarios and in the remaining scenarios had a low willingness-to-pay threshold for all scenarios being cost-effective. In addition, discharge counseling was more cost-effective in the high-risk elderly population compared to the general population. This cost-effectiveness analysis suggests that discharge counseling by pharmacists is quite cost-effective and estimated to be cost saving in over 48% of cases. High-risk elderly patients appear to especially benefit from these pharmacist services.

[Direct and indirect costs associated with respiratory allergic diseases in Italy. A probabilistic cost of illness study].

PubMed

Marcellusi, Andrea; Viti, Raffaella; Incorvaia, Cristoforo; Mennini, Francesco Saverio

2015-10-01

The respiratory allergies, including allergic rhinitis and allergic asthma, represent a substantial medical and economic burden worldwide. Despite their dimension and huge economic-social burden, no data are available on the costs associated with the management of respiratory allergic diseases in Italy. The objective of this study was to estimate the average annual cost incurred by the National Health Service (NHS), as well as society, due to respiratory allergies and their main co-morbidities in Italy. A probabilistic prevalence-based cost of illness model was developed to estimate an aggregate measure of the economic burden associated with respiratory allergies and their main co-morbidities in terms of direct and indirect costs. A systematic literature review was performed in order to identify both the cost per case (expressed in present value) and the number of affected patients, by applying an incidence-based estimation method. Direct costs were estimated multiplying the hospitalization, drugs and management costs derived by the literature with the Italian epidemiological data. Indirect costs were calculated based on lost productivity according to the human capital approach. Furthermore, a one-way and probabilistic sensitivity analysis with 5,000 Monte Carlo simulations were performed, in order to test the robustness of the results and define the proper 95% Confidence Interval (CI). Overall, the total economic burden associated with respiratory allergies and their main co-morbidities was € 7.33 billion (95% CI: € 5.99-€ 8.82). A percentage of 27.5% was associated with indirect costs (€ 2.02; 95% CI: € 1.72-€ 2.34 billion) and 72.5% with direct costs (€ 5.32; 95% CI: € 4.04-€ 6.77 billion). In allergic asthma, allergic rhinitis, combined allergic rhinitis and asthma, turbinate hypertrophy and allergic conjunctivitis, the model estimate an average annual economic burden of € 1,35 (95% CI: € 1,14-€ 1,58) billion, € 1,72 (95% CI: € 1,14-€ 2,43) billion, € 1,62 billion (€ 0,91-€ 2,53) billion, € 0,12 (€ 0,07-€ 0,17) billion, € 0,46 (€ 0,16-€ 0,92) billion respectively. To our knowledge, this is the first study in which direct costs (incurred by NHS) and indirect ones (incurred by the society) were taken into account to estimate the overall burden associated with respiratory allergies and their main co-morbidities in our Country. In conclusion, this work may be considered an efficient tool for public decision-makers to correctly understand the economic aspects involved by the management and treatment of respiratory allergies-induced diseases in Italy.

Why is Probabilistic Seismic Hazard Analysis (PSHA) still used?

NASA Astrophysics Data System (ADS)

Mulargia, Francesco; Stark, Philip B.; Geller, Robert J.

2017-03-01

Even though it has never been validated by objective testing, Probabilistic Seismic Hazard Analysis (PSHA) has been widely used for almost 50 years by governments and industry in applications with lives and property hanging in the balance, such as deciding safety criteria for nuclear power plants, making official national hazard maps, developing building code requirements, and determining earthquake insurance rates. PSHA rests on assumptions now known to conflict with earthquake physics; many damaging earthquakes, including the 1988 Spitak, Armenia, event and the 2011 Tohoku, Japan, event, have occurred in regions relatively rated low-risk by PSHA hazard maps. No extant method, including PSHA, produces reliable estimates of seismic hazard. Earthquake hazard mitigation should be recognized to be inherently political, involving a tradeoff between uncertain costs and uncertain risks. Earthquake scientists, engineers, and risk managers can make important contributions to the hard problem of allocating limited resources wisely, but government officials and stakeholders must take responsibility for the risks of accidents due to natural events that exceed the adopted safety criteria.

Addition of docetaxel and/or zoledronic acid to standard of care for hormone-naive prostate cancer: a cost-effectiveness analysis.

PubMed

Zhang, Pengfei; Wen, Feng; Fu, Ping; Yang, Yu; Li, Qiu

2017-07-31

The effectiveness of the addition of docetaxel and/or zoledronic acid to the standard of care (SOC) for hormone-naive prostate cancer has been evaluated in the STAMPEDE trial. The object of the present analysis was to evaluate the cost-effectiveness of these treatment options in the treatment of advanced hormone-naive prostate cancer in China. A cost-effectiveness analysis using a Markov model was carried out from the Chinese societal perspective. The efficacy data were obtained from the STAMPEDE trial and health utilities were derived from previous studies. Transition probabilities were calculated based on the survival in each group. The primary endpoint in the analysis was the incremental cost-effectiveness ratio (ICER), and model uncertainties were explored by 1-way sensitivity analysis and probabilistic sensitivity analysis. SOC alone generated an effectiveness of 2.65 quality-adjusted life years (QALYs) at a lifetime cost of $20,969.23. At a cost of $25,001.34, SOC plus zoledronic acid was associated with 2.69 QALYs, resulting in an ICER of $100,802.75/QALY compared with SOC alone. SOC plus docetaxel gained an effectiveness of 2.85 QALYs at a cost of $28,764.66, while the effectiveness and cost data in the SOC plus zoledronic acid/docetaxel group were 2.78 QALYs and $32,640.95. Based on the results of the analysis, SOC plus zoledronic acid, SOC plus docetaxel, and SOC plus zoledronic acid/docetaxel are unlikely to be cost-effective options in patients with advanced hormone-naive prostate cancer compared with SOC alone.

Probabilistic choice between symmetric disparities in motion stereo matching for a lateral navigation system

NASA Astrophysics Data System (ADS)

Ershov, Egor; Karnaukhov, Victor; Mozerov, Mikhail

2016-02-01

Two consecutive frames of a lateral navigation camera video sequence can be considered as an appropriate approximation to epipolar stereo. To overcome edge-aware inaccuracy caused by occlusion, we propose a model that matches the current frame to the next and to the previous ones. The positive disparity of matching to the previous frame has its symmetric negative disparity to the next frame. The proposed algorithm performs probabilistic choice for each matched pixel between the positive disparity and its symmetric disparity cost. A disparity map obtained by optimization over the cost volume composed of the proposed probabilistic choice is more accurate than the traditional left-to-right and right-to-left disparity maps cross-check. Also, our algorithm needs two times less computational operations per pixel than the cross-check technique. The effectiveness of our approach is demonstrated on synthetic data and real video sequences, with ground-truth value.

Cost-effectiveness of unicondylar versus total knee arthroplasty: a Markov model analysis.

PubMed

Peersman, Geert; Jak, Wouter; Vandenlangenbergh, Tom; Jans, Christophe; Cartier, Philippe; Fennema, Peter

2014-01-01

Unicondylar knee arthroplasty (UKA) is believed to lead to less morbidity and enhanced functional outcomes when compared with total knee arthroplasty (TKA). Conversely, UKA is also associated with a higher revision risk than TKA. In order to further clarify the key differences between these separate procedures, the current study assessing the cost-effectiveness of UKA versus TKA was undertaken. A state-transition Markov model was developed to compare the cost-effectiveness of UKA versus TKA for unicondylar osteoarthritis using a Belgian payer's perspective. The model was designed to include the possibility of two revision procedures. Model estimates were obtained through literature review and revision rates were based on registry data. Threshold analysis and probabilistic sensitivity analysis were performed to assess the model's robustness. UKA was associated with a cost reduction of €2,807 and a utility gain of 0.04 quality-adjusted life years in comparison with TKA. Analysis determined that the model is sensitive to clinical effectiveness, and that a marginal reduction in the clinical performance of UKA would lead to TKA being the more cost-effective solution. UKA yields clear advantages in terms of costs and marginal advantages in terms of health effects, in comparison with TKA. © 2014 Elsevier B.V. All rights reserved.

Staged decision making based on probabilistic forecasting

NASA Astrophysics Data System (ADS)

Booister, Nikéh; Verkade, Jan; Werner, Micha; Cranston, Michael; Cumiskey, Lydia; Zevenbergen, Chris

2016-04-01

Flood forecasting systems reduce, but cannot eliminate uncertainty about the future. Probabilistic forecasts explicitly show that uncertainty remains. However, as - compared to deterministic forecasts - a dimension is added ('probability' or 'likelihood'), with this added dimension decision making is made slightly more complicated. A technique of decision support is the cost-loss approach, which defines whether or not to issue a warning or implement mitigation measures (risk-based method). With the cost-loss method a warning will be issued when the ratio of the response costs to the damage reduction is less than or equal to the probability of the possible flood event. This cost-loss method is not widely used, because it motivates based on only economic values and is a technique that is relatively static (no reasoning, yes/no decision). Nevertheless it has high potential to improve risk-based decision making based on probabilistic flood forecasting because there are no other methods known that deal with probabilities in decision making. The main aim of this research was to explore the ways of making decision making based on probabilities with the cost-loss method better applicable in practice. The exploration began by identifying other situations in which decisions were taken based on uncertain forecasts or predictions. These cases spanned a range of degrees of uncertainty: from known uncertainty to deep uncertainty. Based on the types of uncertainties, concepts of dealing with situations and responses were analysed and possible applicable concepts where chosen. Out of this analysis the concepts of flexibility and robustness appeared to be fitting to the existing method. Instead of taking big decisions with bigger consequences at once, the idea is that actions and decisions are cut-up into smaller pieces and finally the decision to implement is made based on economic costs of decisions and measures and the reduced effect of flooding. The more lead-time there is in flood event management, the more damage can be reduced. And with decisions based on probabilistic forecasts, partial decisions can be made earlier in time (with a lower probability) and can be scaled up or down later in time when there is more certainty; whether the event takes place or not. Partial decisions are often more cheap, or shorten the final mitigation-time at the moment when there is more certainty. The proposed method is tested on Stonehaven, on the Carron River in Scotland. Decisions to implement demountable defences in the town are currently made based on a very short lead-time due to the absence of certainty. Application showed that staged decision making is possible and gives the decision maker more time to respond to a situation. The decision maker is able to take a lower regret decision with higher uncertainty and less related negative consequences. Although it is not possible to quantify intangible effects, it is part of the analysis to reduce these effects. Above all, the proposed approach has shown to be a possible improvement in economic terms and opens up possibilities of more flexible and robust decision making.

The analysis of probability task completion; Taxonomy of probabilistic thinking-based across gender in elementary school students

NASA Astrophysics Data System (ADS)

Sari, Dwi Ivayana; Budayasa, I. Ketut; Juniati, Dwi

2017-08-01

Formulation of mathematical learning goals now is not only oriented on cognitive product, but also leads to cognitive process, which is probabilistic thinking. Probabilistic thinking is needed by students to make a decision. Elementary school students are required to develop probabilistic thinking as foundation to learn probability at higher level. A framework of probabilistic thinking of students had been developed by using SOLO taxonomy, which consists of prestructural probabilistic thinking, unistructural probabilistic thinking, multistructural probabilistic thinking and relational probabilistic thinking. This study aimed to analyze of probability task completion based on taxonomy of probabilistic thinking. The subjects were two students of fifth grade; boy and girl. Subjects were selected by giving test of mathematical ability and then based on high math ability. Subjects were given probability tasks consisting of sample space, probability of an event and probability comparison. The data analysis consisted of categorization, reduction, interpretation and conclusion. Credibility of data used time triangulation. The results was level of boy's probabilistic thinking in completing probability tasks indicated multistructural probabilistic thinking, while level of girl's probabilistic thinking in completing probability tasks indicated unistructural probabilistic thinking. The results indicated that level of boy's probabilistic thinking was higher than level of girl's probabilistic thinking. The results could contribute to curriculum developer in developing probability learning goals for elementary school students. Indeed, teachers could teach probability with regarding gender difference.

An approximate methods approach to probabilistic structural analysis

NASA Technical Reports Server (NTRS)

Mcclung, R. C.; Millwater, H. R.; Wu, Y.-T.; Thacker, B. H.; Burnside, O. H.

1989-01-01

A major research and technology program in Probabilistic Structural Analysis Methods (PSAM) is currently being sponsored by the NASA Lewis Research Center with Southwest Research Institute as the prime contractor. This program is motivated by the need to accurately predict structural response in an environment where the loadings, the material properties, and even the structure may be considered random. The heart of PSAM is a software package which combines advanced structural analysis codes with a fast probability integration (FPI) algorithm for the efficient calculation of stochastic structural response. The basic idea of PAAM is simple: make an approximate calculation of system response, including calculation of the associated probabilities, with minimal computation time and cost, based on a simplified representation of the geometry, loads, and material. The deterministic solution resulting should give a reasonable and realistic description of performance-limiting system responses, although some error will be inevitable. If the simple model has correctly captured the basic mechanics of the system, however, including the proper functional dependence of stress, frequency, etc. on design parameters, then the response sensitivities calculated may be of significantly higher accuracy.

Funding a smoking cessation program for Crohn's disease: an economic evaluation.

PubMed

Coward, Stephanie; Heitman, Steven J; Clement, Fiona; Negron, Maria; Panaccione, Remo; Ghosh, Subrata; Barkema, Herman W; Seow, Cynthia; Leung, Yvette P Y; Kaplan, Gilaad G

2015-03-01

Patients with Crohn's disease (CD) who smoke are at a higher risk of flaring and requiring surgery. Cost-effectiveness studies of funding smoking cessation programs are lacking. Thus, we performed a cost-utility analysis of funding smoking cessation programs for CD. A cost-utility analysis was performed comparing five smoking cessation strategies: No Program, Counseling, Nicotine Replacement Therapy (NRT), NRT+Counseling, and Varenicline. The time horizon for the Markov model was 5 years. The health states included medical remission (azathioprine or antitumor necrosis factor (anti-TNF), dose escalation of an anti-TNF, second anti-TNF, surgery, and death. Probabilities were taken from peer-reviewed literature, and costs (CAN$) for surgery, medications, and smoking cessation programs were estimated locally. The primary outcome was the cost per quality-adjusted life year (QALY) gained associated with each smoking cessation strategy. Threshold, three-way sensitivity, probabilistic sensitivity analysis (PSA), and budget impact analysis (BIA) were carried out. All strategies dominated No Program. Strategies from most to least cost effective were as follows: Varenicline (cost: $55,614, QALY: 3.70), NRT+Counseling (cost: $58,878, QALY: 3.69), NRT (cost: $59,540, QALY: 3.69), Counseling (cost: $61,029, QALY: 3.68), and No Program (cost: $63,601, QALY: 3.67). Three-way sensitivity analysis demonstrated that No Program was only more cost effective when every strategy's cost exceeded approximately 10 times their estimated costs. The PSA showed that No Program was the most cost-effective <1% of the time. The BIA showed that any strategy saved the health-care system money over No Program. Health-care systems should consider funding smoking cessation programs for CD, as they improve health outcomes and reduce costs.

Necitumumab in Metastatic Squamous Cell Lung Cancer: Establishing a Value-Based Cost.

PubMed

Goldstein, Daniel A; Chen, Qiushi; Ayer, Turgay; Howard, David H; Lipscomb, Joseph; Ramalingam, Suresh S; Khuri, Fadlo R; Flowers, Christopher R

2015-12-01

The SQUIRE trial demonstrated that adding necitumumab to chemotherapy for patients with metastatic squamous cell lung cancer (mSqCLC) increased median overall survival by 1.6 months (hazard ratio, 0.84). However, the costs and value associated with this intervention remains unclear. Value-based pricing links the price of a drug to the benefit that it provides and is a novel method to establish prices for new treatments. To evaluate the range of drug costs for which adding necitumumab to chemotherapy could be considered cost-effective. We developed a Markov model using data from multiple sources, including the SQUIRE trial, which compared standard chemotherapy with and without necitumumab as first-line treatment of mSqCLC, to evaluate the costs and patient life expectancies associated with each regimen. In the analysis, patients were modeled to receive gemcitabine and cisplatin for 6 cycles or gemcitabine, cisplatin, and necitumumab for 6 cycles followed by maintenance necitumumab. Our model's clinical inputs were the survival estimates and frequency of adverse events (AEs) described in the SQUIRE trial. Log-logistic models were fitted to the survival distributions in the SQUIRE trial. The cost inputs included drug costs, based on the Medicare average sale prices, and costs for drug administration and management of AEs, based on Medicare reimbursement rates (all in 2014 US dollars). We evaluated incremental cost-effectiveness ratios (ICERs) for the use of necitumumab across a range of values for its cost. Model robustness was assessed by probabilistic sensitivity analyses, based on 10 000 Monte Carlo simulations, sampling values from the distributions of all model parameters. In the base case analysis, the addition of necitumumab to the treatment regimen produced an incremental survival benefit of 0.15 life-years and 0.11 quality-adjusted life-years (QALYs). The probabilistic sensitivity analyses established that when necitumumab cost less than $563 and less than $1309 per cycle, there was 90% confidence that the ICER for adding necitumumab would be less than $100 000 per QALY and less than $200 000 per QALY, respectively. These findings provide a value-based range for the cost of necitumumab from $563 to $1309 per cycle. This study provides a framework for establishing value-based pricing for new oncology drugs entering the US marketplace.

Cost-effectiveness and budget impact of the fixed-dose dual bronchodilator combination tiotropium–olodaterol for patients with COPD in the Netherlands

PubMed Central

van Boven, Job FM; Kocks, Janwillem WH; Postma, Maarten J

2016-01-01

Purpose The fixed-dose dual bronchodilator combination (FDC) of tiotropium and olodaterol showed increased effectiveness regarding lung function and health-related quality of life in patients with chronic obstructive pulmonary disease (COPD) compared with the use of its mono-components. Yet, while effectiveness and safety have been shown, the health economic implication of this treatment is still unknown. The aim of this study was to assess the cost–utility and budget impact of tiotropium–olodaterol FDC in patients with moderate to very severe COPD in the Netherlands. Patients and methods A cost–utility study was performed, using an individual-level Markov model. To populate the model, individual patient-level data (age, height, sex, COPD duration, baseline forced expiratory volume in 1 second) were obtained from the tiotropium–olodaterol TOnado trial. In the model, forced expiratory volume in 1 second and patient-level data were extrapolated to utility and survival, and treatment with tiotropium–olodaterol FDC was compared with tiotropium. Cost–utility analysis was performed from the Dutch health care payer’s perspective using a 15-year time horizon in the base-case analysis. The standard Dutch discount rates were applied (costs: 4.0%; effects: 1.5%). Both univariate and probabilistic sensitivity analyses were performed. Budget impact was annually assessed over a 5-year time horizon, taking into account different levels of medication adherence. Results As a result of cost increases, combined with quality-adjusted life-year (QALY) gains, results showed that tiotropium–olodaterol FDC had an incremental cost-effectiveness ratio of €7,004/QALY. Without discounting, the incremental cost-effectiveness ratio was €5,981/QALY. Results were robust in univariate and probabilistic sensitivity analyses. Budget impact was estimated at €4.3 million over 5 years assuming 100% medication adherence. Scenarios with 40%, 60%, and 80% adherence resulted in lower 5-year incremental cost increases of €1.7, €2.6, and €3.4 million, respectively. Conclusion Tiotropium–olodaterol FDC can be considered a cost-effective treatment under current Dutch cost-effectiveness thresholds. PMID:27703341

Probabilistic structural analysis methods of hot engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hopkins, D. A.

1989-01-01

Development of probabilistic structural analysis methods for hot engine structures at Lewis Research Center is presented. Three elements of the research program are: (1) composite load spectra methodology; (2) probabilistic structural analysis methodology; and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on high pressure fuel turbopump (HPFT) turbine blade temperature, pressure, and torque of the space shuttle main engine (SSME); (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables; and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.

Probabilistic cost-benefit analysis of disaster risk management in a development context.

PubMed

Kull, Daniel; Mechler, Reinhard; Hochrainer-Stigler, Stefan

2013-07-01

Limited studies have shown that disaster risk management (DRM) can be cost-efficient in a development context. Cost-benefit analysis (CBA) is an evaluation tool to analyse economic efficiency. This research introduces quantitative, stochastic CBA frameworks and applies them in case studies of flood and drought risk reduction in India and Pakistan, while also incorporating projected climate change impacts. DRM interventions are shown to be economically efficient, with integrated approaches more cost-effective and robust than singular interventions. The paper highlights that CBA can be a useful tool if certain issues are considered properly, including: complexities in estimating risk; data dependency of results; negative effects of interventions; and distributional aspects. The design and process of CBA must take into account specific objectives, available information, resources, and the perceptions and needs of stakeholders as transparently as possible. Intervention design and uncertainties should be qualified through dialogue, indicating that process is as important as numerical results. © 2013 The Author(s). Journal compilation © Overseas Development Institute, 2013.

Cost-Effectiveness Analysis of a National Newborn Screening Program for Biotinidase Deficiency.

PubMed

Vallejo-Torres, Laura; Castilla, Iván; Couce, María L; Pérez-Cerdá, Celia; Martín-Hernández, Elena; Pineda, Mercé; Campistol, Jaume; Arrospide, Arantzazu; Morris, Stephen; Serrano-Aguilar, Pedro

2015-08-01

There are conflicting views as to whether testing for biotinidase deficiency (BD) ought to be incorporated into universal newborn screening (NBS) programs. The aim of this study was to evaluate the cost-effectiveness of adding BD to the panel of conditions currently screened under the national NBS program in Spain. We used information from the regional NBS program for BD that has been in place in the Spanish region of Galicia since 1987. These data, along with other sources, were used to develop a cost-effectiveness decision model that compared lifetime costs and health outcomes of a national birth cohort of newborns with and without an early detection program. The analysis took the perspective of the Spanish National Health Service. Effectiveness was measured in terms of quality-adjusted life years (QALYs). We undertook extensive sensitivity analyses around the main model assumptions, including a probabilistic sensitivity analysis. In the base case analysis, NBS for BD led to higher QALYs and higher health care costs, with an estimated incremental cost per QALY gained of $24,677. Lower costs per QALY gained were found when conservative assumptions were relaxed, yielding cost savings in some scenarios. The probability that BD screening was cost-effective was estimated to be >70% in the base case at a standard threshold value. This study indicates that NBS for BD is likely to be a cost-effective use of resources. Copyright © 2015 by the American Academy of Pediatrics.

An economic evaluation of contingency management for completion of hepatitis B vaccination in those on treatment for opiate dependence.

PubMed

Rafia, Rachid; Dodd, Peter J; Brennan, Alan; Meier, Petra S; Hope, Vivian D; Ncube, Fortune; Byford, Sarah; Tie, Hiong; Metrebian, Nicola; Hellier, Jennifer; Weaver, Tim; Strang, John

2016-09-01

To determine whether the provision of contingency management using financial incentives to improve hepatitis B vaccine completion in people who inject drugs entering community treatment represents a cost-effective use of health-care resources. A probabilistic cost-effectiveness analysis was conducted, using a decision-tree to estimate the short-term clinical and health-care cost impact of the vaccination strategies, followed by a Markov process to evaluate the long-term clinical consequences and costs associated with hepatitis B infection. Data on attendance to vaccination from a UK cluster randomized trial. Two contingency management options were examined in the trial: fixed versus escalating schedule financial incentives. Life-time health-care costs and quality-adjusted life years discounted at 3.5% annually; incremental cost-effectiveness ratios. The resulting estimate for the incremental life-time health-care cost of the contingency management strategy versus usual care was £21.86 [95% confidence interval (CI) = -£12.20 to 39.86] per person offered the incentive. For 1000 people offered the incentive, the incremental reduction in numbers of hepatitis B infections avoided over their lifetime was estimated at 19 (95% CI = 8-30). The probabilistic incremental cost per quality adjusted life-year gained of the contingency management programme was estimated to be £6738 (95% CI = £6297-7172), with an 89% probability of being considered cost-effective at a threshold of £20 000 per quality-adjusted life years gained (97.60% at £30 000). Using financial incentives to increase hepatitis B vaccination completion in people who inject drugs could be a cost-effective use of health-care resources in the UK as long as the incidence remains above 1.2%. © 2016 Society for the Study of Addiction.

A Proposed Probabilistic Extension of the Halpern and Pearl Definition of ‘Actual Cause’

PubMed Central

2017-01-01

ABSTRACT Joseph Halpern and Judea Pearl ([2005]) draw upon structural equation models to develop an attractive analysis of ‘actual cause’. Their analysis is designed for the case of deterministic causation. I show that their account can be naturally extended to provide an elegant treatment of probabilistic causation. 1Introduction2Preemption3Structural Equation Models4The Halpern and Pearl Definition of ‘Actual Cause’5Preemption Again6The Probabilistic Case7Probabilistic Causal Models8A Proposed Probabilistic Extension of Halpern and Pearl’s Definition9Twardy and Korb’s Account10Probabilistic Fizzling11Conclusion PMID:29593362

Affordability Engineering: Bridging the Gap Between Design and Cost

NASA Technical Reports Server (NTRS)

Reeves, J. D.; DePasquale, Dominic; Lim, Evan

2010-01-01

Affordability is a commonly used term that takes on numerous meanings depending on the context used. Within conceptual design of complex systems, the term generally implies comparisons between expected costs and expected resources. This characterization is largely correct, but does not convey the many nuances and considerations that are frequently misunderstood and underappreciated. In the most fundamental sense, affordability and cost directly relate to engineering and programmatic decisions made throughout development programs. Systems engineering texts point out that there is a temporal aspect to this relationship, for decisions made earlier in a program dictate design implications much more so than those made during latter phases. This paper explores affordability engineering and its many sub-disciplines by discussing how it can be considered an additional engineering discipline to be balanced throughout the systems engineering and systems analysis processes. Example methods of multidisciplinary design analysis with affordability as a key driver will be discussed, as will example methods of data visualization, probabilistic analysis, and other ways of relating design decisions to affordability results.

Cost-Risk Trade-off of Solar Radiation Management and Mitigation under Probabilistic Information on Climate Sensitivity

NASA Astrophysics Data System (ADS)

Khabbazan, Mohammad Mohammadi; Roshan, Elnaz; Held, Hermann

2017-04-01

In principle solar radiation management (SRM) offers an option to ameliorate anthropogenic temperature rise. However we cannot expect it to simultaneously compensate for anthropogenic changes in further climate variables in a perfect manner. Here, we ask to what extent a proponent of the 2°C-temperature target would apply SRM in conjunction with mitigation in view of global or regional disparities in precipitation changes. We apply cost-risk analysis (CRA), which is a decision analytic framework that makes a trade-off between the expected welfare-loss from climate policy costs and the climate risks from transgressing a climate target. Here, in both global-scale and 'Giorgi'-regional-scale analyses, we evaluate the optimal mixture of SRM and mitigation under probabilistic information about climate sensitivity. To do so, we generalize CRA for the sake of including not only temperature risk, but also globally aggregated and regionally disaggregated precipitation risks. Social welfare is maximized for the following three valuation scenarios: temperature-risk-only, precipitation-risk-only, and equally weighted both-risks. For now, the Giorgi regions are treated by equal weight. We find that for regionally differentiated precipitation targets, the usage of SRM will be comparably more restricted. In the course of time, a cooling of up to 1.3°C can be attributed to SRM for the latter scenario and for a median climate sensitivity of 3°C (for a global target only, this number reduces by 0.5°C). Our results indicate that although SRM would almost completely substitute for mitigation in the globally aggregated analysis, it only saves 70% to 75% of the welfare-loss compared to a purely mitigation-based analysis (from economic costs and climate risks, approximately 4% in terms of BGE) when considering regional precipitation risks in precipitation-risk-only and both-risks scenarios. It remains to be shown how the inclusion of further risks or different regional weights would change that picture.

A Cost-Effectiveness Analysis of Reverse Total Shoulder Arthroplasty versus Hemiarthroplasty for the Management of Complex Proximal Humeral Fractures in the Elderly.

PubMed

Osterhoff, Georg; O'Hara, Nathan N; D'Cruz, Jennifer; Sprague, Sheila A; Bansback, Nick; Evaniew, Nathan; Slobogean, Gerard P

2017-03-01

There is ongoing debate regarding the optimal surgical treatment of complex proximal humeral fractures in elderly patients. To evaluate the cost-effectiveness of reverse total shoulder arthroplasty (RTSA) compared with hemiarthroplasty (HA) in the management of complex proximal humeral fractures, using a cost-utility analysis. On the basis of data from published literature, a cost-utility analysis was conducted using decision tree and Markov modeling. A single-payer perspective, with a willingness-to-pay (WTP) threshold of Can$50,000 (Canadian dollars), and a lifetime time horizon were used. The incremental cost-effectiveness ratio (ICER) was used as the study's primary outcome measure. In comparison with HA, the incremental cost per quality-adjusted life-year gained for RTSA was Can$13,679. One-way sensitivity analysis revealed the model to be sensitive to the RTSA implant cost and the RTSA procedural cost. The ICER of Can$13,679 is well below the WTP threshold of Can$50,000, and probabilistic sensitivity analysis demonstrated that 92.6% of model simulations favored RTSA. Our economic analysis found that RTSA for the treatment of complex proximal humeral fractures in the elderly is the preferred economic strategy when compared with HA. The ICER of RTSA is well below standard WTP thresholds, and its estimate of cost-effectiveness is similar to other highly successful orthopedic strategies such as total hip arthroplasty for the treatment of hip arthritis. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Development of probabilistic multimedia multipathway computer codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, C.; LePoire, D.; Gnanapragasam, E.

2002-01-01

The deterministic multimedia dose/risk assessment codes RESRAD and RESRAD-BUILD have been widely used for many years for evaluation of sites contaminated with residual radioactive materials. The RESRAD code applies to the cleanup of sites (soils) and the RESRAD-BUILD code applies to the cleanup of buildings and structures. This work describes the procedure used to enhance the deterministic RESRAD and RESRAD-BUILD codes for probabilistic dose analysis. A six-step procedure was used in developing default parameter distributions and the probabilistic analysis modules. These six steps include (1) listing and categorizing parameters; (2) ranking parameters; (3) developing parameter distributions; (4) testing parameter distributionsmore » for probabilistic analysis; (5) developing probabilistic software modules; and (6) testing probabilistic modules and integrated codes. The procedures used can be applied to the development of other multimedia probabilistic codes. The probabilistic versions of RESRAD and RESRAD-BUILD codes provide tools for studying the uncertainty in dose assessment caused by uncertain input parameters. The parameter distribution data collected in this work can also be applied to other multimedia assessment tasks and multimedia computer codes.« less

Probabilistic Design and Analysis Framework

NASA Technical Reports Server (NTRS)

Strack, William C.; Nagpal, Vinod K.

2010-01-01

PRODAF is a software package designed to aid analysts and designers in conducting probabilistic analysis of components and systems. PRODAF can integrate multiple analysis programs to ease the tedious process of conducting a complex analysis process that requires the use of multiple software packages. The work uses a commercial finite element analysis (FEA) program with modules from NESSUS to conduct a probabilistic analysis of a hypothetical turbine blade, disk, and shaft model. PRODAF applies the response surface method, at the component level, and extrapolates the component-level responses to the system level. Hypothetical components of a gas turbine engine are first deterministically modeled using FEA. Variations in selected geometrical dimensions and loading conditions are analyzed to determine the effects of the stress state within each component. Geometric variations include the cord length and height for the blade, inner radius, outer radius, and thickness, which are varied for the disk. Probabilistic analysis is carried out using developing software packages like System Uncertainty Analysis (SUA) and PRODAF. PRODAF was used with a commercial deterministic FEA program in conjunction with modules from the probabilistic analysis program, NESTEM, to perturb loads and geometries to provide a reliability and sensitivity analysis. PRODAF simplified the handling of data among the various programs involved, and will work with many commercial and opensource deterministic programs, probabilistic programs, or modules.

Probabilistic Structural Analysis Methods (PSAM) for Select Space Propulsion System Components

NASA Technical Reports Server (NTRS)

1999-01-01

Probabilistic Structural Analysis Methods (PSAM) are described for the probabilistic structural analysis of engine components for current and future space propulsion systems. Components for these systems are subjected to stochastic thermomechanical launch loads. Uncertainties or randomness also occurs in material properties, structural geometry, and boundary conditions. Material property stochasticity, such as in modulus of elasticity or yield strength, exists in every structure and is a consequence of variations in material composition and manufacturing processes. Procedures are outlined for computing the probabilistic structural response or reliability of the structural components. The response variables include static or dynamic deflections, strains, and stresses at one or several locations, natural frequencies, fatigue or creep life, etc. Sample cases illustrates how the PSAM methods and codes simulate input uncertainties and compute probabilistic response or reliability using a finite element model with probabilistic methods.

Cost-Effectiveness Analysis of a Capitated Patient Navigation Program for Medicare Beneficiaries with Lung Cancer.

PubMed

Shih, Ya-Chen Tina; Chien, Chun-Ru; Moguel, Rocio; Hernandez, Mike; Hajek, Richard A; Jones, Lovell A

2016-04-01

To assess the cost-effectiveness of implementing a patient navigation (PN) program with capitated payment for Medicare beneficiaries diagnosed with lung cancer. Cost-effectiveness analysis. A Markov model to capture the disease progression of lung cancer and characterize clinical benefits of PN services as timeliness of treatment and care coordination. Taking a payer's perspective, we estimated the lifetime costs, life years (LYs), and quality-adjusted life years (QALYs) and addressed uncertainties in one-way and probabilistic sensitivity analyses. Model inputs were extracted from the literature, supplemented with data from a Centers for Medicare and Medicaid Services demonstration project. Compared to usual care, PN services incurred higher costs but also yielded better outcomes. The incremental cost and effectiveness was $9,145 and 0.47 QALYs, respectively, resulting in an incremental cost-effectiveness ratio of $19,312/QALY. One-way sensitivity analysis indicated that findings were most sensitive to a parameter capturing PN survival benefit for local-stage patients. CE-acceptability curve showed the probability that the PN program was cost-effective was 0.80 and 0.91 at a societal willingness-to-pay of $50,000 and $100,000/QALY, respectively. Instituting a capitated PN program is cost-effective for lung cancer patients in Medicare. Future research should evaluate whether the same conclusion holds in other cancers. © Health Research and Educational Trust.

Cost-effectiveness analysis of strategies using new immunological diagnostic tests of latent tuberculosis infection before TNF-blockers therapy.

PubMed

Freund, Romain; Granger, Benjamin; Francois, Cécile; Carcelain, Guislaine; Ravaud, Philippe; Mariette, Xavier; Fautrel, Bruno

2018-02-01

Several tests have been proposed to detect latent tuberculosis (LTB). To evaluate the cost-effectiveness of different interferon-gamma release assays based strategies used to screen LTB before tumour necrosis factor (TNF) blockers initiation. Consecutive patients with rheumatoid arthritis, spondyloarthritis or Crohn's disease for whom TNF-blockers were considered, were recruited in 15 tertiary care centres. All were screened for LTB with tuberculin skin test (TST), QuantiFERON TB Gold ® in tube (QFT) and T-SPOT.TB ® (TSpot) on the same day. Cost-minimization and cost-effectiveness analysis, testing 8 screening test combinations, were conducted. Effectiveness was defined as the percentage of LTB treatment avoided and compared with TST alone. Cost were elicited in the payer perspective, included all the costs related to the screening procedure. No tuberculosis reactivation was observed after TNF-blocker initiation. TST followed by QFT if TST was positive was found as the best screening strategy, i.e. the less costly (-54€ compared to reference) and most effective (effectiveness 0.93), resulting in an incremental cost-effectiveness ratio of -192€ per treatment avoided. A probabilistic sensitivity analysis confirmed this result in 72.3% of simulations. TST followed by QFT if TST was positive is the most cost-effective strategy in screening for LTB in patients before starting anti-TNF therapy. NCT00811343. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

The cost of carbon capture and storage for natural gas combined cycle power plants.

PubMed

Rubin, Edward S; Zhai, Haibo

2012-03-20

This paper examines the cost of CO(2) capture and storage (CCS) for natural gas combined cycle (NGCC) power plants. Existing studies employ a broad range of assumptions and lack a consistent costing method. This study takes a more systematic approach to analyze plants with an amine-based postcombustion CCS system with 90% CO(2) capture. We employ sensitivity analyses together with a probabilistic analysis to quantify costs for plants with and without CCS under uncertainty or variability in key parameters. Results for new baseload plants indicate a likely increase in levelized cost of electricity (LCOE) of $20-32/MWh (constant 2007$) or $22-40/MWh in current dollars. A risk premium for plants with CCS increases these ranges to $23-39/MWh and $25-46/MWh, respectively. Based on current cost estimates, our analysis further shows that a policy to encourage CCS at new NGCC plants via an emission tax or carbon price requires (at 95% confidence) a price of at least $125/t CO(2) to ensure NGCC-CCS is cheaper than a plant without CCS. Higher costs are found for nonbaseload plants and CCS retrofits.

Cost-utility analysis of LED fluorescence microscopy in the diagnosis of pulmonary tuberculosis in Indian settings.

PubMed

Kelly, V; Sagili, K D; Satyanarayana, S; Reza, L W; Chadha, S S; Wilson, N C

2015-06-01

With support from the Stop TB Partnership's TB REACH Wave 2 Grant, diagnostic microscopy services for tuberculosis (TB) were upgraded from conventional Ziehl-Neelsen (ZN) based sputum microscopy to light emitting diode technology-based fluorescence microscopy (LED FM) in 200 high-workload microscopy centres in India as a pilot intervention. To evaluate the cost-effectiveness of LED-FM over conventional ZN microscopy to inform further scale-up. A decision-tree model was constructed to assess the cost utility of LED FM over ZN microscopy. The results were summarised using incremental cost-effectiveness ratio (ICER); one-way and probabilistic sensitivity analyses were also conducted to address uncertainty within the model. Data were analysed from 200 medical colleges in 2011 and 2012, before and after the introduction of LED microscopes. A full costing analysis was carried out from the perspective of a national TB programme. The ICER was calculated at US$14.64 per disability-adjusted life-year, with an 82% probability of being cost-effective at a willingness-to-pay threshold equivalent to Indian gross domestic product per capita. LED FM is a cost-effective intervention for detecting TB cases in India at high-workload medical college settings.

Probabilistic Structural Analysis Methods (PSAM) for select space propulsion systems components

NASA Technical Reports Server (NTRS)

1991-01-01

Summarized here is the technical effort and computer code developed during the five year duration of the program for probabilistic structural analysis methods. The summary includes a brief description of the computer code manuals and a detailed description of code validation demonstration cases for random vibrations of a discharge duct, probabilistic material nonlinearities of a liquid oxygen post, and probabilistic buckling of a transfer tube liner.

Health economic evaluation of Human Papillomavirus vaccines in women from Venezuela by a lifetime Markov cohort model.

PubMed

Bardach, Ariel Esteban; Garay, Osvaldo Ulises; Calderón, María; Pichón-Riviére, Andrés; Augustovski, Federico; Martí, Sebastián García; Cortiñas, Paula; Gonzalez, Marino; Naranjo, Laura T; Gomez, Jorge Alberto; Caporale, Joaquín Enzo

2017-02-02

Cervical cancer (CC) and genital warts (GW) are a significant public health issue in Venezuela. Our objective was to assess the cost-effectiveness of the two available vaccines, bivalent and quadrivalent, against Human Papillomavirus (HPV) in Venezuelan girls in order to inform decision-makers. A previously published Markov cohort model, informed by the best available evidence, was adapted to the Venezuelan context to evaluate the effects of vaccination on health and healthcare costs from the perspective of the healthcare payer in an 11-year-old girls cohort of 264,489. Costs and quality-adjusted life years (QALYs) were discounted at 5%. Eight scenarios were analyzed to depict the cost-effectiveness under alternative vaccine prices, exchange rates and dosing schemes. Deterministic and probabilistic sensitivity analyses were performed. Compared to screening only, the bivalent and quadrivalent vaccines were cost-saving in all scenarios, avoiding 2,310 and 2,143 deaths, 4,781 and 4,431 CCs up to 18,459 GW for the quadrivalent vaccine and gaining 4,486 and 4,395 discounted QALYs respectively. For both vaccines, the main determinants of variations in the incremental costs-effectiveness ratio after running deterministic and probabilistic sensitivity analyses were transition probabilities, vaccine and cancer-treatment costs and HPV 16 and 18 distribution in CC cases. When comparing vaccines, none of them was consistently more cost-effective than the other. In sensitivity analyses, for these comparisons, the main determinants were GW incidence, the level of cross-protection and, for some scenarios, vaccines costs. Immunization with the bivalent or quadrivalent HPV vaccines showed to be cost-saving or cost-effective in Venezuela, falling below the threshold of one Gross Domestic Product (GDP) per capita (104,404 VEF) per QALY gained. Deterministic and probabilistic sensitivity analyses confirmed the robustness of these results.

Estimación de la Relación Costo-Efectividad de las Vacunas Neumocócicas Conjugadas Prevenar-13 y Synflorix®, Utilizadas en Los Programas de Vacunación de Población Infantil Mexicana.

PubMed

Gómez, Jorge A; Villaseñor-Sierra, Alberto; Aguilar, Gerardo Martínez; Manjarrez, Roberto Carreño; Cervantes-Apolinar, María Y

2016-12-01

To estimate the cost effectiveness associated with the use of pneumococcal conjugated vaccines, Prevenar-13 and Synflorix®, in the Mexican pediatric population. The cost-effectiveness ratio of instrumenting vaccination programs based upon the use of Prevenar-13 and Synflorix® in the Mexican pediatric population was estimated by using a Markov's simulation model. The robustness of the conclusions reached on cost-effectiveness for both vaccines was assayed through an univariate and probabilistic sensitivity analysis that included all of the parameters considered by the model. Synflorix® was dominant over Prevenar-13 in the cost-utility analysis; the former generated more quality-adjusted life years at a lower cost and with a lower incremental cost-utility ratio. Based on the cost-effective analysis, Prevenar-13 generated more life years gained but at a higher cost. The use of Prevenar-13 originated a higher incremental cost-effectiveness ratio and, therefore, it was not cost-effective as compared with Synflorix®. Even though the simulations for Prevenar-13 and Synflorix® revealed both of them to be cost-effective when used to instrument pediatric vaccination campaigns in Mexico, Synflorix® had a better cost-utility/effectiveness profile. In addition, although Prevenar-13 and Synflorix® produced equivalent health outcomes, the overall analysis predicted that Synflorix® would save 360 million Mexican pesos, as compared with Prevenar-13. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Superposition-Based Analysis of First-Order Probabilistic Timed Automata

NASA Astrophysics Data System (ADS)

Fietzke, Arnaud; Hermanns, Holger; Weidenbach, Christoph

This paper discusses the analysis of first-order probabilistic timed automata (FPTA) by a combination of hierarchic first-order superposition-based theorem proving and probabilistic model checking. We develop the overall semantics of FPTAs and prove soundness and completeness of our method for reachability properties. Basically, we decompose FPTAs into their time plus first-order logic aspects on the one hand, and their probabilistic aspects on the other hand. Then we exploit the time plus first-order behavior by hierarchic superposition over linear arithmetic. The result of this analysis is the basis for the construction of a reachability equivalent (to the original FPTA) probabilistic timed automaton to which probabilistic model checking is finally applied. The hierarchic superposition calculus required for the analysis is sound and complete on the first-order formulas generated from FPTAs. It even works well in practice. We illustrate the potential behind it with a real-life DHCP protocol example, which we analyze by means of tool chain support.

Probabilistic Structural Analysis of the SRB Aft Skirt External Fitting Modification

NASA Technical Reports Server (NTRS)

Townsend, John S.; Peck, J.; Ayala, S.

1999-01-01

NASA has funded several major programs (the PSAM Project is an example) to develop Probabilistic Structural Analysis Methods and tools for engineers to apply in the design and assessment of aerospace hardware. A probabilistic finite element design tool, known as NESSUS, is used to determine the reliability of the Space Shuttle Solid Rocket Booster (SRB) aft skirt critical weld. An external bracket modification to the aft skirt provides a comparison basis for examining the details of the probabilistic analysis and its contributions to the design process.

Early Versus Delayed Surgical Decompression of Spinal Cord after Traumatic Cervical Spinal Cord Injury: A Cost-Utility Analysis.

PubMed

Furlan, Julio C; Craven, B Catharine; Massicotte, Eric M; Fehlings, Michael G

2016-04-01

This cost-utility analysis was undertaken to compare early (≤24 hours since trauma) versus delayed surgical decompression of spinal cord to determine which approach is more cost effective in the management of patients with acute traumatic cervical spinal cord injury (SCI). This study includes the patients enrolled into the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS) and admitted at Toronto Western Hospital. Cases were grouped into patients with motor complete SCI and individuals with motor incomplete SCI. A cost-utility analysis was performed for each group of patients by the use of data for the first 6 months after SCI. The perspective of a public health care insurer was adopted. Costs were estimated in 2014 U.S. dollars. Utilities were estimated from the STASCIS. The baseline analysis indicates early spinal decompression is more cost-effective approach compared with the delayed spinal decompression. When we considered the delayed spinal decompression as the baseline strategy, the incremental cost-effectiveness ratio analysis revealed a saving of US$ 58,368,024.12 per quality-adjusted life years gained for patients with complete SCI and a saving of US$ 536,217.33 per quality-adjusted life years gained in patients with incomplete SCI for the early spinal decompression. The probabilistic analysis confirmed the early-decompression strategy as more cost effective than the delayed-decompression approach, even though there is no clearly dominant strategy. The results of this economic analysis suggests that early decompression of spinal cord was more cost effective than delayed surgical decompression in the management of patients with motor complete and incomplete SCI, even though no strategy was clearly dominant. Copyright © 2016 Elsevier Inc. All rights reserved.

Probabilistic Structural Analysis Theory Development

NASA Technical Reports Server (NTRS)

Burnside, O. H.

1985-01-01

The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

Cost-effectiveness analysis of pneumococcal conjugate vaccines in preventing pneumonia in Peruvian children.

PubMed

Mezones-Holguín, Edward; Bolaños-Díaz, Rafael; Fiestas, Víctor; Sanabria, César; Gutiérrez-Aguado, Alfonso; Fiestas, Fabián; Suárez, Víctor J; Rodriguez-Morales, Alfonso J; Hernández, Adrián V

2014-12-15

Pneumococcal pneumonia (PP) has a high burden of morbimortality in children. Use of pneumococcal conjugate vaccines (PCVs) is an effective preventive measure. After PCV 7-valent (PCV7) withdrawal, PCV 10-valent (PCV10) and PCV 13-valent (PCV13) are the alternatives in Peru. This study aimed to evaluate cost effectiveness of these vaccines in preventing PP in Peruvian children <5 years-old. A cost-effectiveness analysis was developed in three phases: a systematic evidence search for calculating effectiveness; a cost analysis for vaccine strategies and outcome management; and an economic model based on decision tree analysis, including deterministic and probabilistic sensitivity analysis using acceptability curves, tornado diagram, and Monte Carlo simulation. A hypothetic 100 vaccinated children/vaccine cohort was built. An incremental cost-effectiveness ratio (ICER) was calculated. The isolation probability for all serotypes in each vaccine was estimated: 38% for PCV7, 41% PCV10, and 17% PCV13. Avoided hospitalization was found to be the best effectiveness model measure. Estimated costs for PCV7, PCV10, and PCV13 cohorts were USD13,761, 11,895, and 12,499, respectively. Costs per avoided hospitalization were USD718 for PCV7, USD333 for PCV10, and USD 162 for PCV13. At ICER, PCV7 was dominated by the other PCVs. Eliminating PCV7, PCV13 was more cost effective than PCV10 (confirmed in sensitivity analysis). PCV10 and PCV13 are more cost effective than PCV7 in prevention of pneumonia in children <5 years-old in Peru. PCV13 prevents more hospitalizations and is more cost-effective than PCV10. These results should be considered when making decisions about the Peruvian National Inmunizations Schedule.

Real-time adaptive aircraft scheduling

NASA Technical Reports Server (NTRS)

Kolitz, Stephan E.; Terrab, Mostafa

1990-01-01

One of the most important functions of any air traffic management system is the assignment of ground-holding times to flights, i.e., the determination of whether and by how much the take-off of a particular aircraft headed for a congested part of the air traffic control (ATC) system should be postponed in order to reduce the likelihood and extent of airborne delays. An analysis is presented for the fundamental case in which flights from many destinations must be scheduled for arrival at a single congested airport; the formulation is also useful in scheduling the landing of airborne flights within the extended terminal area. A set of approaches is described for addressing a deterministic and a probabilistic version of this problem. For the deterministic case, where airport capacities are known and fixed, several models were developed with associated low-order polynomial-time algorithms. For general delay cost functions, these algorithms find an optimal solution. Under a particular natural assumption regarding the delay cost function, an extremely fast (O(n ln n)) algorithm was developed. For the probabilistic case, using an estimated probability distribution of airport capacities, a model was developed with an associated low-order polynomial-time heuristic algorithm with useful properties.

Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners (Second Edition)

NASA Technical Reports Server (NTRS)

Stamatelatos,Michael; Dezfuli, Homayoon; Apostolakis, George; Everline, Chester; Guarro, Sergio; Mathias, Donovan; Mosleh, Ali; Paulos, Todd; Riha, David; Smith, Curtis;

Cost-effectiveness analysis of population-based tobacco control strategies in the prevention of cardiovascular diseases in Tanzania.

PubMed

Ngalesoni, Frida; Ruhago, George; Mayige, Mary; Oliveira, Tiago Cravo; Robberstad, Bjarne; Norheim, Ole Frithjof; Higashi, Hideki

2017-01-01

Tobacco consumption contributes significantly to the global burden of disease. The prevalence of smoking is estimated to be increasing in many low-income countries, including Tanzania, especially among women and youth. Even so, the implementation of tobacco control measures has been discouraging in the country. Efforts to foster investment in tobacco control are hindered by lack of evidence on what works and at what cost. We aim to estimate the cost and cost-effectiveness of population-based tobacco control strategies in the prevention of cardiovascular diseases (CVD) in Tanzania. A cost-effectiveness analysis was performed using an Excel-based Markov model, from a governmental perspective. We employed an ingredient approach and step-down methodologies in the costing exercise following a government perspective. Epidemiological data and efficacy inputs were derived from the literature. We used disability-adjusted life years (DALYs) averted as the outcome measure. A probabilistic sensitivity analysis was carried out with Ersatz to incorporate uncertainties in the model parameters. Our model results showed that all five tobacco control strategies were very cost-effective since they fell below the ceiling ratio of one GDP per capita suggested by the WHO. Increase in tobacco taxes was the most cost-effective strategy, while a workplace smoking ban was the least cost-effective option, with a cost-effectiveness ratio of US$5 and US$267, respectively. Even though all five interventions are deemed very cost-effective in the prevention of CVD in Tanzania, more research on budget impact analysis is required to further assess the government's ability to implement these interventions.

PREDICT: Privacy and Security Enhancing Dynamic Information Monitoring

DTIC Science & Technology

2015-08-03

consisting of global server-side probabilistic assignment by an untrusted server using cloaked locations, followed by feedback-loop guided local...12], consisting of global server-side probabilistic assignment by an untrusted server using cloaked locations, followed by feedback-loop guided...these methods achieve high sensing coverage with low cost using cloaked locations [3]. In follow-on work, the issue of mobility is addressed. Task

Probabilistic Structural Analysis Methods (PSAM) for select space propulsion system components

NASA Technical Reports Server (NTRS)

1991-01-01

The fourth year of technical developments on the Numerical Evaluation of Stochastic Structures Under Stress (NESSUS) system for Probabilistic Structural Analysis Methods is summarized. The effort focused on the continued expansion of the Probabilistic Finite Element Method (PFEM) code, the implementation of the Probabilistic Boundary Element Method (PBEM), and the implementation of the Probabilistic Approximate Methods (PAppM) code. The principal focus for the PFEM code is the addition of a multilevel structural dynamics capability. The strategy includes probabilistic loads, treatment of material, geometry uncertainty, and full probabilistic variables. Enhancements are included for the Fast Probability Integration (FPI) algorithms and the addition of Monte Carlo simulation as an alternate. Work on the expert system and boundary element developments continues. The enhanced capability in the computer codes is validated by applications to a turbine blade and to an oxidizer duct.

Operations and support cost modeling using Markov chains

NASA Technical Reports Server (NTRS)

Unal, Resit

1989-01-01

Systems for future missions will be selected with life cycle costs (LCC) as a primary evaluation criterion. This reflects the current realization that only systems which are considered affordable will be built in the future due to the national budget constaints. Such an environment calls for innovative cost modeling techniques which address all of the phases a space system goes through during its life cycle, namely: design and development, fabrication, operations and support; and retirement. A significant portion of the LCC for reusable systems are generated during the operations and support phase (OS). Typically, OS costs can account for 60 to 80 percent of the total LCC. Clearly, OS costs are wholly determined or at least strongly influenced by decisions made during the design and development phases of the project. As a result OS costs need to be considered and estimated early in the conceptual phase. To be effective, an OS cost estimating model needs to account for actual instead of ideal processes by associating cost elements with probabilities. One approach that may be suitable for OS cost modeling is the use of the Markov Chain Process. Markov chains are an important method of probabilistic analysis for operations research analysts but they are rarely used for life cycle cost analysis. This research effort evaluates the use of Markov Chains in LCC analysis by developing OS cost model for a hypothetical reusable space transportation vehicle (HSTV) and suggests further uses of the Markov Chain process as a design-aid tool.

Cost-Effectiveness of a Program to Eliminate Disparities in Pneumococcal Vaccination Rates in Elderly Minority Populations: An Exploratory Analysis

PubMed Central

Michaelidis, Constantinos I.; Zimmerman, Richard K.; Nowalk, Mary Patricia; Smith, Kenneth J.

2013-01-01

Objective Invasive pneumococcal disease is a major cause of preventable morbidity and mortality in the United States, particularly among the elderly (>65 years). There are large racial disparities in pneumococcal vaccination rates in this population. Here, we estimate the cost-effectiveness of a hypothetical national vaccination intervention program designed to eliminate racial disparities in pneumococcal vaccination in the elderly. Methods In an exploratory analysis, a Markov decision-analysis model was developed, taking a societal perspective and assuming a 1-year cycle length, 10-year vaccination program duration, and lifetime time horizon. In the base-case analysis, it was conservatively assumed that vaccination program promotion costs were $10 per targeted minority elder per year, regardless of prior vaccination status and resulted in the elderly African American and Hispanic pneumococcal vaccination rate matching the elderly Caucasian vaccination rate (65%) in year 10 of the program. Results The incremental cost-effectiveness of the vaccination program relative to no program was $45,161 per quality-adjusted life-year gained in the base-case analysis. In probabilistic sensitivity analyses, the likelihood of the vaccination program being cost-effective at willingness-to-pay thresholds of $50,000 and $100,000 per quality-adjusted life-year gained was 64% and 100%, respectively. Conclusions In a conservative analysis biased against the vaccination program, a national vaccination intervention program to ameliorate racial disparities in pneumococcal vaccination would be cost-effective. PMID:23538183

Cost-effectiveness of stereotactic radiosurgery versus whole-brain radiation therapy for up to 10 brain metastases.

PubMed

Lester-Coll, Nataniel H; Dosoretz, Arie P; Magnuson, William J; Laurans, Maxwell S; Chiang, Veronica L; Yu, James B

2016-12-01

OBJECTIVE The JLGK0901 study found that stereotactic radiosurgery (SRS) is a safe and effective treatment option for treating up to 10 brain metastases. The purpose of this study is to determine the cost-effectiveness of treating up to 10 brain metastases with SRS, whole-brain radiation therapy (WBRT), or SRS and immediate WBRT (SRS+WBRT). METHODS A Markov model was developed to evaluate the cost effectiveness of SRS, WBRT, and SRS+WBRT in patients with 1 or 2-10 brain metastases. Transition probabilities were derived from the JLGK0901 study and modified according to the recurrence rates observed in the Radiation Therapy Oncology Group (RTOG) 9508 and European Organization for Research and Treatment of Cancer (EORTC) 22952-26001 studies to simulate the outcomes for patients who receive WBRT. Costs are based on 2015 Medicare reimbursements. Health state utilities were prospectively collected using the Standard Gamble method. End points included cost, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). The willingness-to-pay (WTP) threshold was $100,000 per QALY. One-way and probabilistic sensitivity analyses explored uncertainty with regard to the model assumptions. RESULTS In patients with 1 brain metastasis, the ICERs for SRS versus WBRT, SRS versus SRS+WBRT, and SRS+WBRT versus WBRT were $117,418, $51,348, and $746,997 per QALY gained, respectively. In patients with 2-10 brain metastases, the ICERs were $123,256, $58,903, and $821,042 per QALY gained, respectively. On the sensitivity analyses, the model was sensitive to the cost of SRS and the utilities associated with stable post-SRS and post-WBRT states. In patients with 2-10 brain metastases, SRS versus WBRT becomes cost-effective if the cost of SRS is reduced by $3512. SRS versus WBRT was also cost effective at a WTP of $200,000 per QALY on the probabilistic sensitivity analysis. CONCLUSIONS The most cost-effective strategy for patients with up to 10 brain metastases is SRS alone relative to SRS+WBRT. SRS alone may also be cost-effective relative to WBRT alone, but this depends on WTP, the cost of SRS, and patient preferences.

A Two-Stage Probabilistic Approach to Manage Personal Worklist in Workflow Management Systems

NASA Astrophysics Data System (ADS)

Han, Rui; Liu, Yingbo; Wen, Lijie; Wang, Jianmin

The application of workflow scheduling in managing individual actor's personal worklist is one area that can bring great improvement to business process. However, current deterministic work cannot adapt to the dynamics and uncertainties in the management of personal worklist. For such an issue, this paper proposes a two-stage probabilistic approach which aims at assisting actors to flexibly manage their personal worklists. To be specific, the approach analyzes every activity instance's continuous probability of satisfying deadline at the first stage. Based on this stochastic analysis result, at the second stage, an innovative scheduling strategy is proposed to minimize the overall deadline violation cost for an actor's personal worklist. Simultaneously, the strategy recommends the actor a feasible worklist of activity instances which meet the required bottom line of successful execution. The effectiveness of our approach is evaluated in a real-world workflow management system and with large scale simulation experiments.

SETS. Set Equation Transformation System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worrell, R.B.

1992-01-13

SETS is used for symbolic manipulation of Boolean equations, particularly the reduction of equations by the application of Boolean identities. It is a flexible and efficient tool for performing probabilistic risk analysis (PRA), vital area analysis, and common cause analysis. The equation manipulation capabilities of SETS can also be used to analyze noncoherent fault trees and determine prime implicants of Boolean functions, to verify circuit design implementation, to determine minimum cost fire protection requirements for nuclear reactor plants, to obtain solutions to combinatorial optimization problems with Boolean constraints, and to determine the susceptibility of a facility to unauthorized access throughmore » nullification of sensors in its protection system.« less

Cost-effectiveness analysis of acupuncture, counselling and usual care in treating patients with depression: the results of the ACUDep trial.

PubMed

Spackman, Eldon; Richmond, Stewart; Sculpher, Mark; Bland, Martin; Brealey, Stephen; Gabe, Rhian; Hopton, Ann; Keding, Ada; Lansdown, Harriet; Perren, Sara; Torgerson, David; Watt, Ian; MacPherson, Hugh

2014-01-01

New evidence on the clinical effectiveness of acupuncture plus usual care (acupuncture) and counselling plus usual care (counselling) for patients with depression suggests the need to investigate the health-related quality of life and costs of these treatments to understand whether they should be considered a good use of limited health resources. The cost-effectiveness analyses are based on the Acupuncture, Counselling or Usual care for Depression (ACUDep) trial results. Statistical analyses demonstrate a difference in mean quality adjusted life years (QALYs) and suggest differences in mean costs which are mainly due to the price of the interventions. Probabilistic sensitivity analysis is used to express decision uncertainty. Acupuncture and counselling are found to have higher mean QALYs and costs than usual care. In the base case analysis acupuncture has an incremental cost-effectiveness ratio (ICER) of £4,560 per additional QALY and is cost-effective with a probability of 0.62 at a cost-effectiveness threshold of £20,000 per QALY. Counselling compared with acupuncture is more effective and more costly with an ICER of £71,757 and a probability of being cost-effective of 0.36. A scenario analysis of counselling versus usual care, excluding acupuncture as a comparator, results in an ICER of £7,935 and a probability of 0.91. Acupuncture is cost-effective compared with counselling or usual care alone, although the ranking of counselling and acupuncture depends on the relative cost of delivering these interventions. For patients in whom acupuncture is unavailable or perhaps inappropriate, counselling has an ICER less than most cost-effectiveness thresholds. However, further research is needed to determine the most cost-effective treatment pathways for depressed patients when the full range of available interventions is considered.

Probabilistic Evaluation of Advanced Ceramic Matrix Composite Structures

NASA Technical Reports Server (NTRS)

Abumeri, Galib H.; Chamis, Christos C.

2003-01-01

The objective of this report is to summarize the deterministic and probabilistic structural evaluation results of two structures made with advanced ceramic composites (CMC): internally pressurized tube and uniformly loaded flange. The deterministic structural evaluation includes stress, displacement, and buckling analyses. It is carried out using the finite element code MHOST, developed for the 3-D inelastic analysis of structures that are made with advanced materials. The probabilistic evaluation is performed using the integrated probabilistic assessment of composite structures computer code IPACS. The affects of uncertainties in primitive variables related to the material, fabrication process, and loadings on the material property and structural response behavior are quantified. The primitive variables considered are: thermo-mechanical properties of fiber and matrix, fiber and void volume ratios, use temperature, and pressure. The probabilistic structural analysis and probabilistic strength results are used by IPACS to perform reliability and risk evaluation of the two structures. The results will show that the sensitivity information obtained for the two composite structures from the computational simulation can be used to alter the design process to meet desired service requirements. In addition to detailed probabilistic analysis of the two structures, the following were performed specifically on the CMC tube: (1) predicted the failure load and the buckling load, (2) performed coupled non-deterministic multi-disciplinary structural analysis, and (3) demonstrated that probabilistic sensitivities can be used to select a reduced set of design variables for optimization.

Cost-utility analysis of the newly recommended adjuvant chemotherapy for resectable gastric cancer patients in the 2011 Chinese National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology: Gastric Cancer.

PubMed

Chongqing, Tan; Liubao, Peng; Xiaohui, Zeng; Jianhe, Li; Xiaomin, Wan; Gannong, Chen; Siying, Wang; Lihui, Ouyang; Ziying, Zhao

2014-03-01

Postoperative adjuvant chemotherapy with capecitabine and oxaliplatin was first recommended for resectable gastric cancer patients in the 2011 Chinese National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Gastric Cancer, but the economic influence of this therapy in China is unknown. The aim of the present study was to determine the cost-effectiveness of adjuvant chemotherapy with capecitabine and oxaliplatin after a gastrectomy with extended (D2) lymph-node dissection, compared with a D2 gastrectomy alone, for patients with stage II-IIIB gastric cancer. On the basis of data from the CLASSIC trial, a Markov model was created to determine economic and clinical data for patients in the chemotherapy and surgery group (CSG) and the surgery-only group (SOG). The costs, presented in 2010 US dollars and estimated from the perspective of the Chinese health-care system, were obtained from the published literature and the local health system. The utilities were based on published literature. Costs, life years (LYs), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICER) were estimated. A lifetime horizon and a 3 % annual discount rate were used. One-way and probabilistic sensitivity analyses were performed. For the base case, the CSG compared with SOG would increase LYs and QALYs in a 3-, 5-, 10- or 30-year time horizon (except the QALYs at 3 or 5 years). In the short run (such as in 3 or 5 years), the medical costs would increase owing to adjuvant chemotherapy of capecitabine plus oxaliplatin after D2 gastrectomy, but in the long run the costs would decline. The ICERs suggested that the SOG was dominant at 3 or 5 years and the CSG was dominant at 10 or 30 years. The one-way sensitivity analysis showed that the utility of disease-free survival for 1-10 years for the SOG and the cost of oxaliplatin were the most influential parameters. The probabilistic sensitivity analysis predicted a 98.6 % likelihood that the ICER for the CSG would be less than US$13,527/QALY (three times the per capita gross domestic product of China). For patients in China with resectable disease, our results suggest that adjuvant chemotherapy with capecitabine plus oxaliplatin after a D2 gastrectomy is cost-saving and dominant in the long run on the basis of a current clinical trial, compared with treatment with a D2 gastrectomy alone.

Cost-effectiveness analysis of triple therapy with protease inhibitors in treatment-naive hepatitis C patients.

PubMed

Blázquez-Pérez, Antonio; San Miguel, Ramón; Mar, Javier

2013-10-01

Chronic hepatitis C is the leading cause of chronic liver disease, representing a significant burden in terms of morbidity, mortality and costs. A new scenario of therapy for hepatitis C virus (HCV) genotype 1 infection is being established with the approval of two effective HCV protease inhibitors (PIs) in combination with the standard of care (SOC), peginterferon and ribavirin. Our objective was to estimate the cost effectiveness of combination therapy with new PIs (boceprevir and telaprevir) plus peginterferon and ribavirin versus SOC in treatment-naive patients with HCV genotype 1 according to data obtained from clinical trials (CTs). A Markov model simulating chronic HCV progression was used to estimate disease treatment costs and effects over patients' lifetimes, in the Spanish national public healthcare system. The target population was treatment-naive patients with chronic HCV genotype 1, demographic characteristics for whom were obtained from the published pivotal CTs SPRINT and ADVANCE. Three options were analysed for each PI based on results from the two CTs: universal triple therapy, interleukin (IL)-28B-guided therapy and dual therapy with peginterferon and ribavirin. A univariate sensitivity analysis was performed to evaluate the uncertainty of certain parameters: age at start of treatment, transition probabilities, drug costs, CT efficacy results and a higher hazard ratio for all-cause mortality for patients with chronic HCV. Probabilistic sensitivity analyses were also carried out. Incremental cost-effectiveness ratios (ICERs) of €2012 per quality-adjusted life-year (QALY) gained were used as outcome measures. According to the base-case analysis, using dual therapy as the comparator, the alternative IL28B-guided therapy presents a more favorable ICER (€18,079/QALY for boceprevir and €25,914/QALY for telaprevir) than the universal triple therapy option (€27,594/QALY for boceprevir and €33,751/QALY for telaprevir), with an ICER clearly below the efficiency threshold for medical interventions in the Spanish setting. Sensitivity analysis showed that age at the beginning of treatment was an important factor that influenced the ICER. A potential reduction in PI costs would also clearly improve the ICER, and transition probabilities influenced the results, but to a lesser extent. Probabilistic sensitivity analyses showed that 95 % of the simulations presented an ICER below €40,000/QALY. Post hoc estimations of sustained virological responses of the IL28B-guided therapeutic option represented a limitation of the study. The therapeutic options analysed for the base-case cohort can be considered cost-effective interventions for the Spanish healthcare framework. Sensitivity analysis estimated an acceptability threshold of the IL28B-guided strategy of patients younger than 60 years.

A cost-utility analysis of dabigatran, enoxaparin, and usual care for venous thromboprophylaxis after hip or knee replacement surgery in Thailand.

PubMed

Kotirum, Surachai; Chongmelaxme, Bunchai; Chaiyakunapruk, Nathorn

2017-02-01

To analyze the cost-utility of oral dabigatran etexilate, enoxaparin sodium injection, and no intervention for venous thromboembolism (VTE) prophylaxis after total hip or knee replacement (THR/TKR) surgery among Thai patients. A cost-utility analysis using a decision tree model was conducted using societal and healthcare payers' perspectives to simulate relevant costs and health outcomes covering a 3-month time horizon. Costs were adjusted to year 2014. The willingness-to-pay threshold of THB 160,000 (USD 4926) was used. One-way sensitivity and probabilistic sensitivity analyses using a Monte Carlo simulation were performed. Compared with no VTE prophylaxis, dabigatran and enoxaparin after THR and TKR surgery incurred higher costs and increased quality adjusted life years (QALYs). However, their incremental cost-effectiveness ratios were high above the willingness to pay. Compared with enoxaparin, dabigatran for THR/TKR lowered VTE complications but increased bleeding cases; dabigatran was cost-saving by reducing the costs [by THB 3809.96 (USD 117.30) for THR] and producing more QALYs gained (by 0.00013 for THR). Dabigatran (vs. enoxaparin) had a 98 % likelihood of being cost effective. Dabigatran is cost-saving compared to enoxaparin for VTE prophylaxis after THR or TKR under the Thai context. However, both medications are not cost-effective compared to no thromboprophylaxis.

Cost-Effective Marine Protection - A Pragmatic Approach

PubMed Central

Oinonen, Soile; Hyytiäinen, Kari; Ahlvik, Lassi; Laamanen, Maria; Lehtoranta, Virpi; Salojärvi, Joona; Virtanen, Jarno

2016-01-01

This paper puts forward a framework for probabilistic and holistic cost-effectiveness analysis to provide support in selecting the least-cost set of measures to reach a multidimensional environmental objective. Following the principles of ecosystem-based management, the framework includes a flexible methodology for deriving and populating criteria for effectiveness and costs and analyzing complex ecological-economic trade-offs under uncertainty. The framework is applied in the development of the Finnish Programme of Measures (PoM) for reaching the targets of the EU Marine Strategy Framework Directive (MSFD). The numerical results demonstrate that substantial cost savings can be realized from careful consideration of the costs and multiple effects of management measures. If adopted, the proposed PoM would yield improvements in the state of the Baltic Sea, but the overall objective of the MSFD would not be reached by the target year of 2020; for various environmental and administrative reasons, it would take longer for most measures to take full effect. PMID:26751965

Probabilistic QoS Analysis In Wireless Sensor Networks

DTIC Science & Technology

2012-04-01

and A.O. Fapojuwo. TDMA scheduling with optimized energy efficiency and minimum delay in clustered wireless sensor networks . IEEE Trans. on Mobile...Research Computer Science and Engineering, Department of 5-1-2012 Probabilistic QoS Analysis in Wireless Sensor Networks Yunbo Wang University of...Wang, Yunbo, "Probabilistic QoS Analysis in Wireless Sensor Networks " (2012). Computer Science and Engineering: Theses, Dissertations, and Student

Process for computing geometric perturbations for probabilistic analysis

DOEpatents

Fitch, Simeon H. K. [Charlottesville, VA; Riha, David S [San Antonio, TX; Thacker, Ben H [San Antonio, TX

2012-04-10

A method for computing geometric perturbations for probabilistic analysis. The probabilistic analysis is based on finite element modeling, in which uncertainties in the modeled system are represented by changes in the nominal geometry of the model, referred to as "perturbations". These changes are accomplished using displacement vectors, which are computed for each node of a region of interest and are based on mean-value coordinate calculations.

Cost-Utility Analysis of Lurasidone Versus Aripiprazole in Adults with Schizophrenia.

PubMed

Rajagopalan, Krithika; Trueman, David; Crowe, Lydia; Squirrell, Daniel; Loebel, Antony

2016-07-01

In 2014, lurasidone, an atypical antipsychotic, was approved for the treatment of schizophrenia in adults. It is an alternative treatment option to aripiprazole, and when compared with aripiprazole, lurasidone was associated with improved symptom reduction and reduced risk of weight gain and relapse. We conducted a cost-utility analysis of lurasidone versus aripiprazole from the perspective of healthcare services, using Scotland and Wales as specific case studies. A 10-year Markov model, incorporating a 6-week acute phase and a maintenance phase across three health states (discontinuation, relapse, death) was constructed. Six-week probabilities of discontinuation and adverse events were based on a published independent mixed-treatment comparison; long-term risks of relapse and discontinuation were from an indirect comparison. Costs included drug therapy, relapse, and outpatient, primary and residential care. Costs and benefits were discounted at 3.5 %. Utility estimates were taken from published literature, and cost effectiveness was expressed as total 10-year incremental costs and quality-adjusted life-years (QALYs). Lurasidone yielded a cost saving of £3383 and an improvement of 0.005 QALYs versus aripiprazole, in Scotland. Deterministic sensitivity analysis demonstrated that results were sensitive to relapse rates, while probabilistic sensitivity analysis suggested that lurasidone had the highest expected net benefit at willingness-to-pay thresholds of £20,000-30,000 per QALY. The probability that lurasidone was a cost-effective treatment strategy was approximately 75 % at all willingness-to-pay thresholds, with similar results being obtained for the Welsh analysis. Our analysis suggests that lurasidone would provide an effective, cost-saving alternative for the healthcare service in the treatment of adult patients with schizophrenia.

Methodological framework for the probabilistic risk assessment of multi-hazards at a municipal scale: a case study in the Fella river valley, Eastern Italian Alps

NASA Astrophysics Data System (ADS)

Hussin, Haydar; van Westen, Cees; Reichenbach, Paola

2013-04-01

Local and regional authorities in mountainous areas that deal with hydro-meteorological hazards like landslides and floods try to set aside budgets for emergencies and risk mitigation. However, future losses are often not calculated in a probabilistic manner when allocating budgets or determining how much risk is acceptable. The absence of probabilistic risk estimates can create a lack of preparedness for reconstruction and risk reduction costs and a deficiency in promoting risk mitigation and prevention in an effective way. The probabilistic risk of natural hazards at local scale is usually ignored all together due to the difficulty in acknowledging, processing and incorporating uncertainties in the estimation of losses (e.g. physical damage, fatalities and monetary loss). This study attempts to set up a working framework for a probabilistic risk assessment (PRA) of landslides and floods at a municipal scale using the Fella river valley (Eastern Italian Alps) as a multi-hazard case study area. The emphasis is on the evaluation and determination of the uncertainty in the estimation of losses from multi-hazards. To carry out this framework some steps are needed: (1) by using physically based stochastic landslide and flood models we aim to calculate the probability of the physical impact on individual elements at risk, (2) this is then combined with a statistical analysis of the vulnerability and monetary value of the elements at risk in order to include their uncertainty in the risk assessment, (3) finally the uncertainty from each risk component is propagated into the loss estimation. The combined effect of landslides and floods on the direct risk to communities in narrow alpine valleys is also one of important aspects that needs to be studied.

A cost effectiveness analysis of thiopurine methyltransferase testing for guiding 6-mercaptopurine dosing in children with acute lymphoblastic leukemia.

PubMed

Donnan, Jennifer R; Ungar, Wendy J; Mathews, Maria; Hancock-Howard, Rebecca L; Rahman, Proton

2011-08-01

An increased understanding of the genetic basis of disease creates a demand for personalized medicine and more genetic testing for diagnosis and treatment. The objective was to assess the incremental cost-effectiveness per life-month gained of thiopurine methyltransferase (TPMT) genotyping to guide doses of 6-mercaptopurine (6-MP) in children with acute lymphoblastic leukemia (ALL) compared to enzymatic testing and standard weight-based dosing. A cost-effectiveness analysis was conducted from a health care system perspective comparing costs and consequences over 3 months. Decision analysis was used to evaluate the impact of TPMT tests on preventing myelosuppression and improving survival in ALL patients receiving 6-MP. Direct medical costs included laboratory tests, medications, physician services, pharmacy and inpatient care. Probabilities were derived from published evidence. Survival was measured in life-months. The robustness of the results to variable uncertainty was tested in one-way sensitivity analyses. Probabilistic sensitivity analysis examined the impact of parameter uncertainty and generated confidence intervals around point estimates. Neither of the testing interventions showed a benefit in survival compared to weight-based dosing. Both test strategies were more costly compared to weight-based dosing. Incremental costs per child (95% confidence interval) were $277 ($112, $442) and $298 ($392, $421) for the genotyping and phenotyping strategies, respectively, compared to weight-based dosing. The present analysis suggests that screening for TPMT mutations using either genotype or enzymatic laboratory tests prior to the administration of 6-MP in pediatric ALL patients is not cost-effective. Copyright © 2011 Wiley-Liss, Inc.

Probabilistic dual heuristic programming-based adaptive critic

NASA Astrophysics Data System (ADS)

Herzallah, Randa

2010-02-01

Adaptive critic (AC) methods have common roots as generalisations of dynamic programming for neural reinforcement learning approaches. Since they approximate the dynamic programming solutions, they are potentially suitable for learning in noisy, non-linear and non-stationary environments. In this study, a novel probabilistic dual heuristic programming (DHP)-based AC controller is proposed. Distinct to current approaches, the proposed probabilistic (DHP) AC method takes uncertainties of forward model and inverse controller into consideration. Therefore, it is suitable for deterministic and stochastic control problems characterised by functional uncertainty. Theoretical development of the proposed method is validated by analytically evaluating the correct value of the cost function which satisfies the Bellman equation in a linear quadratic control problem. The target value of the probabilistic critic network is then calculated and shown to be equal to the analytically derived correct value. Full derivation of the Riccati solution for this non-standard stochastic linear quadratic control problem is also provided. Moreover, the performance of the proposed probabilistic controller is demonstrated on linear and non-linear control examples.

A cost analysis of first-line chemotherapy for low-risk gestational trophoblastic neoplasia.

PubMed

Shah, Neel T; Barroilhet, Lisa; Berkowitz, Ross S; Goldstein, Donald P; Horowitz, Neil

2012-01-01

To determine the optimal approach to first-line treatment for low-risk gestational trophoblastic neoplasia (GTN) using a cost analysis of 3 commonly used regimens. A decision tree of the 3 most commonly used first-line low-risk GTN treatment strategies was created, accounting for toxicities, response rates and need for second- or third-line therapy. These strategies included 8-day methotrexate (MTX)/folinic acid, weekly MTX, and pulsed actinomycin-D (act-D). Response rates, average number of cycles needed for remission, and toxicities were determined by review of the literature. Costs of each strategy were examined from a societal perspective, including the direct total treatment costs as well as the indirect lost labor production costs from work absences. Sensitivity analysis on these costs was performed using both deterministic and probabilistic cost-minimization models with the aid of decision tree software (TreeAge Pro 2011, TreeAge Inc., Williamstown, Massachusetts). We found that 8-day MTX/folinic acid is the least expensive to society, followed by pulsed act-D ($4,867 vs. $6,111 average societal cost per cure, respectively), with act-D becoming more favorable only with act-D per-cycle cost <$231, or response rate to first-line therapy > 99%. Weekly MTX is the most expensive first-line treatment strategy to society ($9,089 average cost per cure), despite being least expensive to administer per cycle, based on lower first-line response rate. Absolute societal cost of each strategy is driven by the probability of needing expensive third-line multiagent chemotherapy, however relative cost differences are robust to sensitivity analysis over the reported range of cycle number and response rate for all therapies. Based on similar efficacy and lower societal cost, we recommend 8-day MTX/folinic acid for first-line treatment of low-risk GTN.

Cost-effectiveness analysis of left atrial appendage occlusion compared with pharmacological strategies for stroke prevention in atrial fibrillation.

PubMed

Lee, Vivian Wing-Yan; Tsai, Ronald Bing-Ching; Chow, Ines Hang-Iao; Yan, Bryan Ping-Yen; Kaya, Mehmet Gungor; Park, Jai-Wun; Lam, Yat-Yin

2016-08-31

Transcatheter left atrial appendage occlusion (LAAO) is a promising therapy for stroke prophylaxis in non-valvular atrial fibrillation (NVAF) but its cost-effectiveness remains understudied. This study evaluated the cost-effectiveness of LAAO for stroke prophylaxis in NVAF. A Markov decision analytic model was used to compare the cost-effectiveness of LAAO with 7 pharmacological strategies: aspirin alone, clopidogrel plus aspirin, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban. Outcome measures included quality-adjusted life years (QALYs), lifetime costs and incremental cost-effectiveness ratios (ICERs). Base-case data were derived from ACTIVE, RE-LY, ARISTOTLE, ROCKET-AF, PROTECT-AF and PREVAIL trials. One-way sensitivity analysis varied by CHADS2 score, HAS-BLED score, time horizons, and LAAO costs; and probabilistic sensitivity analysis using 10,000 Monte Carlo simulations was conducted to assess parameter uncertainty. LAAO was considered cost-effective compared with aspirin, clopidogrel plus aspirin, and warfarin, with ICER of US$5,115, $2,447, and $6,298 per QALY gained, respectively. LAAO was dominant (i.e. less costly but more effective) compared to other strategies. Sensitivity analysis demonstrated favorable ICERs of LAAO against other strategies in varied CHADS2 score, HAS-BLED score, time horizons (5 to 15 years) and LAAO costs. LAAO was cost-effective in 86.24 % of 10,000 simulations using a threshold of US$50,000/QALY. Transcatheter LAAO is cost-effective for prevention of stroke in NVAF compared with 7 pharmacological strategies. The transcatheter left atrial appendage occlusion (LAAO) is considered cost-effective against the standard 7 oral pharmacological strategies including acetylsalicylic acid (ASA) alone, clopidogrel plus ASA, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban for stroke prophylaxis in non-valvular atrial fibrillation management.

Cost-effectiveness of Human Papilloma Virus (HPV) vaccination in Nigeria: a decision analysis using pragmatic parameter estimates for cost and programme coverage.

PubMed

Ekwunife, Obinna I; Lhachimi, Stefan K

2017-12-08

World Health Organisation recommends routine Human Papilloma Virus (HPV) vaccination for girls when its cost-effectiveness in the country or region has been duly considered. We therefore aimed to evaluate cost-effectiveness of HPV vaccination in Nigeria using pragmatic parameter estimates for cost and programme coverage, i.e. realistically achievable in the studied context. A microsimulation frame-work was used. The natural history for cervical cancer disease was remodelled from a previous Nigerian model-based study. Costing was based on health providers' perspective. Disability adjusted life years attributable to cervical cancer mortality served as benefit estimate. Suitable policy option was obtained by calculating the incremental costs-effectiveness ratio. Probabilistic sensitivity analysis was used to assess parameter uncertainty. One-way sensitivity analysis was used to explore the robustness of the policy recommendation to key parameters alteration. Expected value of perfect information (EVPI) was calculated to determine the expected opportunity cost associated with choosing the optimal scenario or strategy at the maximum cost-effectiveness threshold. Combination of the current scenario of opportunistic screening and national HPV vaccination programme (CS + NV) was the only cost-effective and robust policy option. However, CS + NV scenario was only cost-effective so far the unit cost of HPV vaccine did not exceed $5. EVPI analysis showed that it may be worthwhile to conduct additional research to inform the decision to adopt CS + NV. National HPV vaccination combined with opportunist cervical cancer screening is cost-effective in Nigeria. However, adoption of this strategy should depend on its relative efficiency when compared to other competing new vaccines and health interventions.

Alvimopan, a peripherally acting μ-opioid receptor antagonist, is associated with reduced costs after radical cystectomy: economic analysis of a phase 4 randomized, controlled trial.

PubMed

Kauf, Teresa L; Svatek, Robert S; Amiel, Gilad; Beard, Timothy L; Chang, Sam S; Fergany, Amr; Karnes, R Jeffrey; Koch, Michael; O'Hara, Jerome; Lee, Cheryl T; Sexton, Wade J; Slaton, Joel W; Steinberg, Gary D; Wilson, Shandra S; Techner, Lee; Martin, Carolyn; Moreno, Jessica; Kamat, Ashish M

2014-06-01

We evaluated the effect of alvimopan treatment vs placebo on health care utilization and costs related to gastrointestinal recovery in patients treated with radical cystectomy in a randomized, phase 4 clinical trial. Resource utilization data were prospectively collected and evaluated by cost consequence analysis. Hospital costs were estimated from 2012 Medicare reimbursement rates and medication wholesale acquisition costs. Differences in base case mean costs between the study cohorts for total postoperative ileus related costs (hospital days, study drug, nasogastric tubes, postoperative ileus related concomitant medication and postoperative ileus related readmissions) and total combined costs (postoperative ileus related, laboratory, electrocardiograms, nonpostoperative ileus related concomitant medication and nonpostoperative ileus related readmission) were evaluated by probabilistic sensitivity analysis using a bootstrap approach. Mean hospital stay was 2.63 days shorter for alvimopan than placebo (mean±SD 8.44±3.05 vs 11.07±8.23 days, p=0.005). Use of medications or interventions likely intended to diagnose or manage postoperative ileus was lower for alvimopan than for placebo, eg total parenteral nutrition 10% vs 25% (p=0.001). Postoperative ileus related health care costs were $2,340 lower for alvimopan and mean total combined costs were decreased by $2,640 per patient for alvimopan vs placebo. Analysis using a 10,000-iteration bootstrap approach showed that the mean difference in postoperative ileus related costs (p=0.04) but not total combined costs (p=0.068) was significantly lower for alvimopan than for placebo. In patients treated with radical cystectomy alvimopan decreased hospitalization cost by reducing the health care services associated with postoperative ileus and decreasing the hospital stay. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Probabilistic teleportation via multi-parameter measurements and partially entangled states

NASA Astrophysics Data System (ADS)

Wei, Jiahua; Shi, Lei; Han, Chen; Xu, Zhiyan; Zhu, Yu; Wang, Gang; Wu, Hao

2018-04-01

In this paper, a novel scheme for probabilistic teleportation is presented with multi-parameter measurements via a non-maximally entangled state. This is in contrast to the fact that the measurement kinds for quantum teleportation are usually particular in most previous schemes. The detail implementation producers for our proposal are given by using of appropriate local unitary operations. Moreover, the total success probability and classical information of this proposal are calculated. It is demonstrated that the success probability and classical cost would be changed with the multi-measurement parameters and the entanglement factor of quantum channel. Our scheme could enlarge the research range of probabilistic teleportation.

Probabilistic Risk Assessment (PRA): A Practical and Cost Effective Approach

NASA Technical Reports Server (NTRS)

Lee, Lydia L.; Ingegneri, Antonino J.; Djam, Melody

2006-01-01

The Lunar Reconnaissance Orbiter (LRO) is the first mission of the Robotic Lunar Exploration Program (RLEP), a space exploration venture to the Moon, Mars and beyond. The LRO mission includes spacecraft developed by NASA Goddard Space Flight Center (GSFC) and seven instruments built by GSFC, Russia, and contractors across the nation. LRO is defined as a measurement mission, not a science mission. It emphasizes the overall objectives of obtaining data to facilitate returning mankind safely to the Moon in preparation for an eventual manned mission to Mars. As the first mission in response to the President's commitment of the journey of exploring the solar system and beyond: returning to the Moon in the next decade, then venturing further into the solar system, ultimately sending humans to Mars and beyond, LRO has high-visibility to the public but limited resources and a tight schedule. This paper demonstrates how NASA's Lunar Reconnaissance Orbiter Mission project office incorporated reliability analyses in assessing risks and performing design tradeoffs to ensure mission success. Risk assessment is performed using NASA Procedural Requirements (NPR) 8705.5 - Probabilistic Risk Assessment (PRA) Procedures for NASA Programs and Projects to formulate probabilistic risk assessment (PRA). As required, a limited scope PRA is being performed for the LRO project. The PRA is used to optimize the mission design within mandated budget, manpower, and schedule constraints. The technique that LRO project office uses to perform PRA relies on the application of a component failure database to quantify the potential mission success risks. To ensure mission success in an efficient manner, low cost and tight schedule, the traditional reliability analyses, such as reliability predictions, Failure Modes and Effects Analysis (FMEA), and Fault Tree Analysis (FTA), are used to perform PRA for the large system of LRO with more than 14,000 piece parts and over 120 purchased or contractor built components.

The cost-effectiveness of mandatory 20 mph zones for the prevention of injuries.

PubMed

Peters, Jaime L; Anderson, Rob

2013-03-01

Traffic calming and speed limits are major public health strategies for further reducing road injuries, especially for vulnerable pedestrians such as children and the elderly. We conducted a cost-benefit analysis (CBA-favoured by transport economists) alongside a cost-utility analysis (CUA-favoured by health economists) of mandatory 20 mph zones, providing a unique opportunity to compare assumptions and results. A CUA from the public sector perspective and a CBA from a broader societal perspective. One-way, threshold and probabilistic sensitivity analyses were undertaken. In low casualty areas the intervention was not cost-effective regardless of approach (CUA: cost per QALY = £429 800; CBA: net present value = -£25 500). In high casualty areas, the intervention was cost-effective from the CBA (a saving of £90 600), but not from the CUA [cost per quality-adjusted life year (QALY) = £86 500; assuming National Institute for Health and Clinical Excellence's benchmark for approving health technologies]. Mandatory 20 mph zones may be cost-effective in high casualty areas when a CBA from a societal perspective is considered. Although CBA may appear, in principle, more appropriate, the quality, age or absence of reliable data for many parameters means that there is a great deal of uncertainty and the results should be interpreted with caution.

PREMChlor: Probabilistic Remediation Evaluation Model for Chlorinated Solvents

DTIC Science & Technology

2010-03-01

Council O&M Operation & Management PAT pump-and-treat PCE tetrachloroethylene PDFs Probability density functions PRBs Permeable reactive barriers...includes a one-time capital cost and a total operation & management (O&M) cost in present net value (NPV) for a certain remediation period. The...Generally, the costs of plume treatment include the capital cost (treatment volume multiply by the unit cost) and the annual operation & Management (O&M

Optimizing water purchases for an Environmental Water Account

NASA Astrophysics Data System (ADS)

Lund, J. R.; Hollinshead, S. P.

2005-12-01

State and federal agencies in California have established an Environmental Water Account (EWA) to buy water to protect endangered fish in the San Francisco Bay/ Sacramento-San Joaquin Delta Estuary. This paper presents a three-stage probabilistic optimization model that identifies least-cost strategies for purchasing water for the EWA given hydrologic, operational, and biological uncertainties. This approach minimizes the expected cost of long-term, spot, and option water purchases to meet uncertain flow dedications for fish. The model prescribes the location, timing, and type of optimal water purchases and can illustrate how least-cost strategies change with hydrologic, operational, biological, and cost inputs. Details of the optimization model's application to California's EWA are provided with a discussion of its utility for strategic planning and policy purposes. Limitations in and sensitivity analysis of the model's representation of EWA operations are discussed, as are operational and research recommendations.

Probabilistic structural analysis using a general purpose finite element program

NASA Astrophysics Data System (ADS)

Riha, D. S.; Millwater, H. R.; Thacker, B. H.

1992-07-01

This paper presents an accurate and efficient method to predict the probabilistic response for structural response quantities, such as stress, displacement, natural frequencies, and buckling loads, by combining the capabilities of MSC/NASTRAN, including design sensitivity analysis and fast probability integration. Two probabilistic structural analysis examples have been performed and verified by comparison with Monte Carlo simulation of the analytical solution. The first example consists of a cantilevered plate with several point loads. The second example is a probabilistic buckling analysis of a simply supported composite plate under in-plane loading. The coupling of MSC/NASTRAN and fast probability integration is shown to be orders of magnitude more efficient than Monte Carlo simulation with excellent accuracy.

Probabilistic Analysis of Combinatorial Optimization Problems on Hypergraph Matchings

DTIC Science & Technology

2012-02-01

per dimension” ( recall that d is equal to the number of independent subsets of vertices Vk in the hypergraph Hd jn, and n denotes the number of...disjoint solutions whose costs are iid random variables. First, recalling the interpretation of feasible MAP solu- tions as paths in the index graph G, we...elements. On the other hand, recall that a (feasible) path G can be described as a set of n vectors D f.i .1/ 1 ; : : : ; i .1/ d /; : : : ; .i .n

Cost-Effectiveness Analysis of Isavuconazole vs. Voriconazole as First-Line Treatment for Invasive Aspergillosis.

PubMed

Harrington, Rachel; Lee, Edward; Yang, Hongbo; Wei, Jin; Messali, Andrew; Azie, Nkechi; Wu, Eric Q; Spalding, James

2017-01-01

Invasive aspergillosis (IA) is associated with a significant clinical and economic burden. The phase III SECURE trial demonstrated non-inferiority in clinical efficacy between isavuconazole and voriconazole. No studies have evaluated the cost-effectiveness of isavuconazole compared to voriconazole. The objective of this study was to evaluate the costs and cost-effectiveness of isavuconazole vs. voriconazole for the first-line treatment of IA from the US hospital perspective. An economic model was developed to assess the costs and cost-effectiveness of isavuconazole vs. voriconazole in hospitalized patients with IA. The time horizon was the duration of hospitalization. Length of stay for the initial admission, incidence of readmission, clinical response, overall survival rates, and experience of adverse events (AEs) came from the SECURE trial. Unit costs were from the literature. Total costs per patient were estimated, composed of drug costs, costs of AEs, and costs of hospitalizations. Incremental costs per death avoided and per additional clinical responders were reported. Deterministic and probabilistic sensitivity analyses (DSA and PSA) were conducted. Base case analysis showed that isavuconazole was associated with a $7418 lower total cost per patient than voriconazole. In both incremental costs per death avoided and incremental costs per additional clinical responder, isavuconazole dominated voriconazole. Results were robust in sensitivity analysis. Isavuconazole was cost saving and dominant vs. voriconazole in most DSA. In PSA, isavuconazole was cost saving in 80.2% of the simulations and cost-effective in 82.0% of the simulations at the $50,000 willingness to pay threshold per additional outcome. Isavuconazole is a cost-effective option for the treatment of IA among hospitalized patients. Astellas Pharma Global Development, Inc.

Costs and cost-effectiveness of pediatric inguinal hernia repair in Uganda.

PubMed

Eeson, Gareth; Birabwa-Male, Doreen; Pennington, Mark; Blair, Geoffrey K

2015-02-01

Surgically treatable diseases contribute approximately 11% of disability-adjusted life years (DALYs) worldwide yet they remain a neglected public health priority in low- and middle-income countries (LMICs). Pediatric inguinal hernia is the most common congenital abnormality in newborns and a major cause of morbidity and mortality yet elective repair remains largely unavailable in LMICs. This study is aimed to determine the costs and cost-effectiveness of pediatric inguinal hernia repair (PIHR) in a low-resource setting. Medical costs of consecutive elective PIHRs were recorded prospectively at two centers in Uganda. Decision modeling was used to compare two different treatment scenarios (adoption of PIHR and non-adoption) from a provider perspective. A Markov model was constructed to estimate health outcomes under each scenario. The robustness of the cost-effectiveness results in the base case analysis was tested in one-way and probabilistic sensitivity analysis. The primary outcome of interest was cost per DALY averted by the intervention. Sixty-nine PIHRs were performed in 65 children (mean age 3.6 years). Mean cost per procedure was $86.68 US (95% CI 83.1-90.2 USD) and averted an average of 5.7 DALYs each. Incremental cost-effectiveness ratio was $12.41 per DALY averted. The probability of cost-effectiveness was 95% at a cost-effectiveness threshold of $35 per averted DALY. Results were robust to sensitivity analysis under all considered scenarios. Elective PIHR is highly cost-effective for the treatment and prevention of complications of hernia disease even in low-resource settings. PIHR should be prioritized in LMICs alongside other cost-effective interventions.

An economic evaluation of highly purified HMG and recombinant FSH based on a large randomized trial.

PubMed

Wechowski, Jaroslaw; Connolly, Mark; McEwan, Philip; Kennedy, Richard

2007-11-01

Public funding for IVF is increasingly being challenged by health authorities in an attempt to minimize health service costs. In light of treatment rationing, the need to consider costs in relation to outcomes is paramount. To assess the cost implications of gonadotrophin treatment options, an economic evaluation comparing highly purified human menopausal gonadotrophin (HP-HMG) and recombinant FSH (rFSH) has been conducted. The analysis is based on individual patient data from a large randomized controlled trial (n = 731) in a long agonist IVF protocol. The economic evaluation uses a discrete event simulation model to assess treatment costs in relation to live births for both treatments based on published UK costs. After one cycle the mean costs per IVF treatment for HP-HMG and rFSH were pound2396 (95% CI pound2383-2414) and pound2633 ( pound2615-2652), respectively. The average cost-saving of pound237 per IVF cycle using HP-HMG allows one additional cycle to be delivered for every 10 cycles. With maternal and neonatal costs applied, the median cost per IVF baby delivered with HP-HMG was pound8893 compared with pound11,741 for rFSH (P < 0.001). The cost-saving potential of HP-HMG in IVF was still apparent after varying critical cost parameters in the probabilistic sensitivity analysis.

Propulsion Airframe Aeroacoustics Technology Evaluation and Selection Using a Multi-Attribute Decision Making Process and Non-Deterministic Design

NASA Technical Reports Server (NTRS)

Burg, Cecile M.; Hill, Geoffrey A.; Brown, Sherilyn A.; Geiselhart, Karl A.

2004-01-01

The Systems Analysis Branch at NASA Langley Research Center has investigated revolutionary Propulsion Airframe Aeroacoustics (PAA) technologies and configurations for a Blended-Wing-Body (BWB) type aircraft as part of its research for NASA s Quiet Aircraft Technology (QAT) Project. Within the context of the long-term NASA goal of reducing the perceived aircraft noise level by a factor of 4 relative to 1997 state of the art, major configuration changes in the propulsion airframe integration system were explored with noise as a primary design consideration. An initial down-select and assessment of candidate PAA technologies for the BWB was performed using a Multi-Attribute Decision Making (MADM) process consisting of organized brainstorming and decision-making tools. The assessments focused on what effect the PAA technologies had on both the overall noise level of the BWB and what effect they had on other major design considerations such as weight, performance and cost. A probabilistic systems analysis of the PAA configurations that presented the best noise reductions with the least negative impact on the system was then performed. Detailed results from the MADM study and the probabilistic systems analysis will be published in the near future.

Cost-effectiveness of percutaneous coronary intervention with cobalt-chromium everolimus eluting stents versus bare metal stents: Results from a patient level meta-analysis of randomized trials.

PubMed

Ferko, Nicole; Ferrante, Giuseppe; Hasegawa, James T; Schikorr, Tanya; Soleas, Ireena M; Hernandez, John B; Sabaté, Manel; Kaiser, Christoph; Brugaletta, Salvatore; de la Torre Hernandez, Jose Maria; Galatius, Soeren; Cequier, Angel; Eberli, Franz; de Belder, Adam; Serruys, Patrick W; Valgimigli, Marco

2017-05-01

Second-generation drug eluting stents (DES) may reduce costs and improve clinical outcomes compared to first-generation DES with improved cost-effectiveness when compared to bare metal stents (BMS). We aimed to conduct an economic evaluation of a cobalt-chromium everolimus eluting stent (Co-Cr EES) compared with BMS in percutaneous coronary intervention (PCI). To conduct a cost-effectiveness analysis (CEA) of a cobalt-chromium everolimus eluting stent (Co-Cr EES) versus BMS in PCI. A Markov state transition model with a 2-year time horizon was applied from a US Medicare setting with patients undergoing PCI with Co-Cr EES or BMS. Baseline characteristics, treatment effects, and safety measures were taken from a patient level meta-analysis of 5 RCTs (n = 4,896). The base-case analysis evaluated stent-related outcomes; a secondary analysis considered the broader set of outcomes reported in the meta-analysis. The base-case and secondary analyses reported an additional 0.018 and 0.013 quality-adjusted life years (QALYs) and cost savings of $236 and $288, respectively with Co-Cr EES versus BMS. Results were robust to sensitivity analyses and were most sensitive to the price of clopidogrel. In the probabilistic sensitivity analysis, Co-Cr EES was associated with a greater than 99% chance of being cost saving or cost effective (at a cost per QALY threshold of $50,000) versus BMS. Using data from a recent patient level meta-analysis and contemporary cost data, this analysis found that PCI with Co-Cr EES is more effective and less costly than PCI with BMS. © 2016 The Authors. Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc. © 2016 The Authors. Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc.

Cost-effectiveness Analysis of Nutritional Support for the Prevention of Pressure Ulcers in High-Risk Hospitalized Patients.

PubMed

Tuffaha, Haitham W; Roberts, Shelley; Chaboyer, Wendy; Gordon, Louisa G; Scuffham, Paul A

2016-06-01

To evaluate the cost-effectiveness of nutritional support compared with standard care in preventing pressure ulcers (PrUs) in high-risk hospitalized patients. An economic model using data from a systematic literature review. A meta-analysis of randomized controlled trials on the efficacy of nutritional support in reducing the incidence of PrUs was conducted. Modeled cohort of hospitalized patients at high risk of developing PrUs and malnutrition simulated during their hospital stay and up to 1 year. Standard care included PrU prevention strategies, such as redistribution surfaces, repositioning, and skin protection strategies, along with standard hospital diet. In addition to the standard care, the intervention group received nutritional support comprising patient education, nutrition goal setting, and the consumption of high-protein supplements. The analysis was from a healthcare payer perspective. Key outcomes of the model included the average costs and quality-adjusted life years. Model results were tested in univariate sensitivity analyses, and decision uncertainty was characterized using a probabilistic sensitivity analysis. Compared with standard care, nutritional support was cost saving at AU $425 per patient and marginally more effective with an average 0.005 quality-adjusted life years gained. The probability of nutritional support being cost-effective was 87%. Nutritional support to prevent PrUs in high-risk hospitalized patients is cost-effective with substantial cost savings predicted. Hospitals should implement the recommendations from the current PrU practice guidelines and offer nutritional support to high-risk patients.

Modelling the cost-effectiveness of impact-absorbing flooring in Swedish residential care facilities.

PubMed

Ryen, Linda; Svensson, Mikael

2016-06-01

Fall-related injuries among the elderly, specifically hip fractures, cause significant morbidity and mortality as well as imposing a substantial financial cost on the health care system. Impact-absorbing flooring has been advocated as an effective method for preventing hip fractures resulting from falls. This study identifies the cost-effectiveness of impact-absorbing flooring compared to standard flooring in residential care facilities for the elderly in a Swedish setting. An incremental cost-effectiveness analysis was performed comparing impact-absorbing flooring to standard flooring using a Markov decision model. A societal perspective was adopted and incremental costs were compared to incremental gains in quality-adjusted life years (QALYs). Data on costs, probability transitions and health-related quality of life measures were retrieved from the published literature and from Swedish register data. Probabilistic sensitivity analysis was performed through a Monte Carlo simulation. The base-case analysis indicates that the impact-absorbing flooring reduces costs and increases QALYs. When allowing for uncertainty we find that 60% of the simulations indicate that impact-absorbing flooring is cost-saving compared to standard flooring and an additional 20% that it has a cost per QALY below a commonly used threshold value : Using a modelling approach, we find that impact-absorbing flooring is a dominant strategy at the societal level considering that it can save resources and improve health in a vulnerable population. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Pharmacoeconomic analysis of recombinant factor VIIa versus APCC in the treatment of minor-to-moderate bleeds in hemophilia patients with inhibitors.

PubMed

Joshi, Ashish V; Stephens, Jennifer M; Munro, Vicki; Mathew, Prasad; Botteman, Marc F

2006-01-01

To compare the cost-effectiveness of three treatment regimens using recombinant activated Factor VII (rFVIIa), NovoSeven, and activated prothrombin-complex concentrate (APCC), FEIBA VH, for home treatment of minor-to-moderate bleeds in hemophilia patients with inhibitors. A literature-based, decision-analytic model was developed to compare three treatment regimens. The regimens consisting of first-, second-, and third-line treatments were: rFVIIa-rFVIIa-rFVIIa; APCC-rFVIIa-rFVIIa; and APCC-APCC-rFVIIa. Patients not responding to first-line treatment were administered second-line treatment, and those failing second-line received third-line treatment. Using literature and expert opinion, the model structure and base-case inputs were adapted to the US from a previously published analysis. The percentage of evaluable bleeds controlled with rFVIIa and APCC were obtained from published literature. Drug costs (2005 US$) based on average wholesale price were included in the base-case model. Univariate and probabilistic sensitivity analyses (second-order Monte Carlo simulation) were conducted by varying the efficacy, re-bleeding rates, patient weight, and dosing to ascertain robustness of the model. In the base-case analysis, the average cost per resolved bleed using rFVIIa as first-, second-, and third-line treatment was $28 076. Using APCC as first-line and rFVIIa as second- and third-line treatment resulted in an average cost per resolved bleed of $30 883, whereas the regimen using APCC as first- and second-line, and rFVIIa as third-line treatment was the most expensive, with an average cost per resolved bleed of $32 150. Cost offsets occurred for the rFVIIa-only regimen through avoidance of second and third lines of treatment. In probabilistic sensitivity analyses, the rFVIIa-only strategy was the least expensive strategy more than 68% of the time. The management of minor-to-moderate bleeds extends beyond the initial line of treatment, and should include the economic impact of re-bleeding and failures over multiple lines of treatment. In the majority of cases, the rFVIIa-only regimen appears to be a less expensive treatment option in inhibitor patients with minor-to-moderate bleeds over three lines of treatment.

Screening test recommendations for methicillin-resistant Staphylococcus aureus surveillance practices: A cost-minimization analysis.

PubMed

Whittington, Melanie D; Curtis, Donna J; Atherly, Adam J; Bradley, Cathy J; Lindrooth, Richard C; Campbell, Jonathan D

2017-07-01

To mitigate methicillin-resistant Staphylococcus aureus (MRSA) infections, intensive care units (ICUs) conduct surveillance through screening patients upon admission followed by adhering to isolation precautions. Two surveillance approaches commonly implemented are universal preemptive isolation and targeted isolation of only MRSA-positive patients. Decision analysis was used to calculate the total cost of universal preemptive isolation and targeted isolation. The screening test used as part of the surveillance practice was varied to identify which screening test minimized inappropriate and total costs. A probabilistic sensitivity analysis was conducted to evaluate the range of total costs resulting from variation in inputs. The total cost of the universal preemptive isolation surveillance practice was minimized when a polymerase chain reaction screening test was used ($82.51 per patient). Costs were $207.60 more per patient when a conventional culture was used due to the longer turnaround time and thus higher isolation costs. The total cost of the targeted isolation surveillance practice was minimized when chromogenic agar 24-hour testing was used ($8.54 per patient). Costs were $22.41 more per patient when polymerase chain reaction was used. For ICUs that preemptively isolate all patients, the use of a polymerase chain reaction screening test is recommended because it can minimize total costs by reducing inappropriate isolation costs. For ICUs that only isolate MRSA-positive patients, the use of chromogenic agar 24-hour testing is recommended to minimize total costs. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Probabilistic Mass Growth Uncertainties

NASA Technical Reports Server (NTRS)

Plumer, Eric; Elliott, Darren

2013-01-01

Mass has been widely used as a variable input parameter for Cost Estimating Relationships (CER) for space systems. As these space systems progress from early concept studies and drawing boards to the launch pad, their masses tend to grow substantially, hence adversely affecting a primary input to most modeling CERs. Modeling and predicting mass uncertainty, based on historical and analogous data, is therefore critical and is an integral part of modeling cost risk. This paper presents the results of a NASA on-going effort to publish mass growth datasheet for adjusting single-point Technical Baseline Estimates (TBE) of masses of space instruments as well as spacecraft, for both earth orbiting and deep space missions at various stages of a project's lifecycle. This paper will also discusses the long term strategy of NASA Headquarters in publishing similar results, using a variety of cost driving metrics, on an annual basis. This paper provides quantitative results that show decreasing mass growth uncertainties as mass estimate maturity increases. This paper's analysis is based on historical data obtained from the NASA Cost Analysis Data Requirements (CADRe) database.

Enhancing Cost Realism through Risk-Driven Contracting: Designing Incentive Fees Based on Probabilistic Cost Estimates

DTIC Science & Technology

2012-04-01

Comparison of Management Practices in the Army, Navy, and Air Force 142Defense ARJ, April 2012, Vol. 19 No. 2 : 133–160 It appears the pendulum may be...the cost risk for requiring greater innovation. However, this natural flattening trend also leads to a potential drawback of the risk-driven

Historical clinical and economic consequences of anemia management in patients with end-stage renal disease on dialysis using erythropoietin stimulating agents versus routine blood transfusions: a retrospective cost-effectiveness analysis.

PubMed

Naci, Huseyin; de Lissovoy, Gregory; Hollenbeak, Christopher; Custer, Brian; Hofmann, Axel; McClellan, William; Gitlin, Matthew

2012-01-01

To determine whether Medicare's decision to cover routine administration of erythropoietin stimulating agents (ESAs) to treat anemia of end-stage renal disease (ESRD) has been a cost-effective policy relative to standard of care at the time. The authors used summary statistics from the actual cohort of ESRD patients receiving ESAs between 1995 and 2004 to create a simulated patient cohort, which was compared with a comparable simulated cohort assumed to rely solely on blood transfusions. Outcomes modeled from the Medicare perspective included estimated treatment costs, life-years gained, and quality-adjusted life-years (QALYs). Incremental cost-effectiveness ratio (ICER) was calculated relative to the hypothetical reference case of no ESA use in the transfusion cohort. Sensitivity of the results to model assumptions was tested using one-way and probabilistic sensitivity analyses. Estimated total costs incurred by the ESRD population were $155.47B for the cohort receiving ESAs and $155.22B for the cohort receiving routine blood transfusions. Estimated QALYs were 2.56M and 2.29M, respectively, for the two groups. The ICER of ESAs compared to routine blood transfusions was estimated as $873 per QALY gained. The model was sensitive to a number of parameters according to one-way and probabilistic sensitivity analyses. This model was counter-factual as the actual comparison group, whose anemia was managed via transfusion and iron supplements, rapidly disappeared following introduction of ESAs. In addition, a large number of model parameters were obtained from observational studies due to the lack of randomized trial evidence in the literature. This study indicates that Medicare's coverage of ESAs appears to have been cost effective based on commonly accepted levels of willingness-to-pay. The ESRD population achieved substantial clinical benefit at a reasonable cost to society.

Climate change risk analysis framework (CCRAF) a probabilistic tool for analyzing climate change uncertainties

NASA Astrophysics Data System (ADS)

Legget, J.; Pepper, W.; Sankovski, A.; Smith, J.; Tol, R.; Wigley, T.

2003-04-01

Potential risks of human-induced climate change are subject to a three-fold uncertainty associated with: the extent of future anthropogenic and natural GHG emissions; global and regional climatic responses to emissions; and impacts of climatic changes on economies and the biosphere. Long-term analyses are also subject to uncertainty regarding how humans will respond to actual or perceived changes, through adaptation or mitigation efforts. Explicitly addressing these uncertainties is a high priority in the scientific and policy communities Probabilistic modeling is gaining momentum as a technique to quantify uncertainties explicitly and use decision analysis techniques that take advantage of improved risk information. The Climate Change Risk Assessment Framework (CCRAF) presented here a new integrative tool that combines the probabilistic approaches developed in population, energy and economic sciences with empirical data and probabilistic results of climate and impact models. The main CCRAF objective is to assess global climate change as a risk management challenge and to provide insights regarding robust policies that address the risks, by mitigating greenhouse gas emissions and by adapting to climate change consequences. The CCRAF endogenously simulates to 2100 or beyond annual region-specific changes in population; GDP; primary (by fuel) and final energy (by type) use; a wide set of associated GHG emissions; GHG concentrations; global temperature change and sea level rise; economic, health, and biospheric impacts; costs of mitigation and adaptation measures and residual costs or benefits of climate change. Atmospheric and climate components of CCRAF are formulated based on the latest version of Wigley's and Raper's MAGICC model and impacts are simulated based on a modified version of Tol's FUND model. The CCRAF is based on series of log-linear equations with deterministic and random components and is implemented using a Monte-Carlo method with up to 5000 variants per set of fixed input parameters. The shape and coefficients of CCRAF equations are derived from regression analyses of historic data and expert assessments. There are two types of random components in CCRAF - one reflects a year-to-year fluctuations around the expected value of a given variable (e.g., standard error of the annual GDP growth) and another is fixed within each CCRAF variant and represents some essential constants within a "world" represented by that variant (e.g., the value of climate sensitivity). Both types of random components are drawn from pre-defined probability distributions functions developed based on historic data or expert assessments. Preliminary CCRAF results emphasize the relative importance of uncertainties associated with the conversion of GHG and particulate emissions into radiative forcing and quantifying climate change effects at the regional level. A separates analysis involves an "adaptive decision-making", which optimizes the expected future policy effects given the estimated probabilistic uncertainties. As uncertainty for some variables evolve over the time steps, the decisions also adapt. This modeling approach is feasible only with explicit modeling of uncertainties.

Alternate Methods in Refining the SLS Nozzle Plug Loads

NASA Technical Reports Server (NTRS)

Burbank, Scott; Allen, Andrew

2013-01-01

Numerical analysis has shown that the SLS nozzle environmental barrier (nozzle plug) design is inadequate for the prelaunch condition, which consists of two dominant loads: 1) the main engines startup pressure and 2) an environmentally induced pressure. Efforts to reduce load conservatisms included a dynamic analysis which showed a 31% higher safety factor compared to the standard static analysis. The environmental load is typically approached with a deterministic method using the worst possible combinations of pressures and temperatures. An alternate probabilistic approach, utilizing the distributions of pressures and temperatures, resulted in a 54% reduction in the environmental pressure load. A Monte Carlo simulation of environmental load that used five years of historical pressure and temperature data supported the results of the probabilistic analysis, indicating the probabilistic load is reflective of a 3-sigma condition (1 in 370 probability). Utilizing the probabilistic load analysis eliminated excessive conservatisms and will prevent a future overdesign of the nozzle plug. Employing a similar probabilistic approach to other design and analysis activities can result in realistic yet adequately conservative solutions.

A comprehensive probabilistic analysis model of oil pipelines network based on Bayesian network

NASA Astrophysics Data System (ADS)

Zhang, C.; Qin, T. X.; Jiang, B.; Huang, C.

2018-02-01

Oil pipelines network is one of the most important facilities of energy transportation. But oil pipelines network accident may result in serious disasters. Some analysis models for these accidents have been established mainly based on three methods, including event-tree, accident simulation and Bayesian network. Among these methods, Bayesian network is suitable for probabilistic analysis. But not all the important influencing factors are considered and the deployment rule of the factors has not been established. This paper proposed a probabilistic analysis model of oil pipelines network based on Bayesian network. Most of the important influencing factors, including the key environment condition and emergency response are considered in this model. Moreover, the paper also introduces a deployment rule for these factors. The model can be used in probabilistic analysis and sensitive analysis of oil pipelines network accident.

Cost-utility analysis of percutaneous mitral valve repair in inoperable patients with functional mitral regurgitation in German settings.

PubMed

Borisenko, Oleg; Haude, Michael; Hoppe, Uta C; Siminiak, Tomasz; Lipiecki, Janusz; Goldberg, Steve L; Mehta, Nawzer; Bouknight, Omari V; Bjessmo, Staffan; Reuter, David G

2015-05-14

To determine the cost-effectiveness of the percutaneous mitral valve repair (PMVR) using Carillon® Mitral Contour System® (Cardiac Dimensions Inc., Kirkland, WA, USA) in patients with congestive heart failure accompanied by moderate to severe functional mitral regurgitation (FMR) compared to the prolongation of optimal medical treatment (OMT). Cost-utility analysis using a combination of a decision tree and Markov process was performed. The clinical effectiveness was determined based on the results of the Transcatheter Implantation of Carillon Mitral Annuloplasty Device (TITAN) trial. The mean age of the target population was 62 years, 77% of the patients were males, 64% of the patients had severe FMR and all patients had New York Heart Association functional class III. The epidemiological, cost and utility data were derived from the literature. The analysis was performed from the German statutory health insurance perspective over 10-year time horizon. Over 10 years, the total cost was €36,785 in the PMVR arm and €18,944 in the OMT arm. However, PMVR provided additional benefits to patients with an 1.15 incremental quality-adjusted life years (QALY) and an 1.41 incremental life years. The percutaneous procedure was cost-effective in comparison to OMT with an incremental cost-effectiveness ratio of €15,533/QALY. Results were robust in the deterministic sensitivity analysis. In the probabilistic sensitivity analysis with a willingness-to-pay threshold of €35,000/QALY, PMVR had a 84 % probability of being cost-effective. Percutaneous mitral valve repair may be cost-effective in inoperable patients with FMR due to heart failure.

Costs and cost-effectiveness of training traditional birth attendants to reduce neonatal mortality in the Lufwanyama Neonatal Survival study (LUNESP).

PubMed

Sabin, Lora L; Knapp, Anna B; MacLeod, William B; Phiri-Mazala, Grace; Kasimba, Joshua; Hamer, Davidson H; Gill, Christopher J

2012-01-01

The Lufwanyama Neonatal Survival Project ("LUNESP") was a cluster randomized, controlled trial that showed that training traditional birth attendants (TBAs) to perform interventions targeting birth asphyxia, hypothermia, and neonatal sepsis reduced all-cause neonatal mortality by 45%. This companion analysis was undertaken to analyze intervention costs and cost-effectiveness, and factors that might improve cost-effectiveness. We calculated LUNESP's financial and economic costs and the economic cost of implementation for a forecasted ten-year program (2011-2020). In each case, we calculated the incremental cost per death avoided and disability-adjusted life years (DALYs) averted in real 2011 US dollars. The forecasted 10-year program analysis included a base case as well as 'conservative' and 'optimistic' scenarios. Uncertainty was characterized using one-way sensitivity analyses and a multivariate probabilistic sensitivity analysis. The estimated financial and economic costs of LUNESP were $118,574 and $127,756, respectively, or $49,469 and $53,550 per year. Fixed costs accounted for nearly 90% of total costs. For the 10-year program, discounted total and annual program costs were $256,455 and $26,834 respectively; for the base case, optimistic, and conservative scenarios, the estimated cost per death avoided was $1,866, $591, and $3,024, and cost per DALY averted was $74, $24, and $120, respectively. Outcomes were robust to variations in local costs, but sensitive to variations in intervention effect size, number of births attended by TBAs, and the extent of foreign consultants' participation. Based on established guidelines, the strategy of using trained TBAs to reduce neonatal mortality was 'highly cost effective'. We strongly recommend consideration of this approach for other remote rural populations with limited access to health care.

Costs and Cost-Effectiveness of Training Traditional Birth Attendants to Reduce Neonatal Mortality in the Lufwanyama Neonatal Survival Study (LUNESP)

PubMed Central

Sabin, Lora L.; Knapp, Anna B.; MacLeod, William B.; Phiri-Mazala, Grace; Kasimba, Joshua; Hamer, Davidson H.; Gill, Christopher J.

2012-01-01

Background The Lufwanyama Neonatal Survival Project (“LUNESP”) was a cluster randomized, controlled trial that showed that training traditional birth attendants (TBAs) to perform interventions targeting birth asphyxia, hypothermia, and neonatal sepsis reduced all-cause neonatal mortality by 45%. This companion analysis was undertaken to analyze intervention costs and cost-effectiveness, and factors that might improve cost-effectiveness. Methods and Findings We calculated LUNESP's financial and economic costs and the economic cost of implementation for a forecasted ten-year program (2011–2020). In each case, we calculated the incremental cost per death avoided and disability-adjusted life years (DALYs) averted in real 2011 US dollars. The forecasted 10-year program analysis included a base case as well as ‘conservative’ and ‘optimistic’ scenarios. Uncertainty was characterized using one-way sensitivity analyses and a multivariate probabilistic sensitivity analysis. The estimated financial and economic costs of LUNESP were $118,574 and $127,756, respectively, or $49,469 and $53,550 per year. Fixed costs accounted for nearly 90% of total costs. For the 10-year program, discounted total and annual program costs were $256,455 and $26,834 respectively; for the base case, optimistic, and conservative scenarios, the estimated cost per death avoided was $1,866, $591, and $3,024, and cost per DALY averted was $74, $24, and $120, respectively. Outcomes were robust to variations in local costs, but sensitive to variations in intervention effect size, number of births attended by TBAs, and the extent of foreign consultants' participation. Conclusions Based on established guidelines, the strategy of using trained TBAs to reduce neonatal mortality was ‘highly cost effective’. We strongly recommend consideration of this approach for other remote rural populations with limited access to health care. PMID:22545117

Process-based Cost Estimation for Ramjet/Scramjet Engines

NASA Technical Reports Server (NTRS)

Singh, Brijendra; Torres, Felix; Nesman, Miles; Reynolds, John

2003-01-01

Process-based cost estimation plays a key role in effecting cultural change that integrates distributed science, technology and engineering teams to rapidly create innovative and affordable products. Working together, NASA Glenn Research Center and Boeing Canoga Park have developed a methodology of process-based cost estimation bridging the methodologies of high-level parametric models and detailed bottoms-up estimation. The NASA GRC/Boeing CP process-based cost model provides a probabilistic structure of layered cost drivers. High-level inputs characterize mission requirements, system performance, and relevant economic factors. Design alternatives are extracted from a standard, product-specific work breakdown structure to pre-load lower-level cost driver inputs and generate the cost-risk analysis. As product design progresses and matures the lower level more detailed cost drivers can be re-accessed and the projected variation of input values narrowed, thereby generating a progressively more accurate estimate of cost-risk. Incorporated into the process-based cost model are techniques for decision analysis, specifically, the analytic hierarchy process (AHP) and functional utility analysis. Design alternatives may then be evaluated not just on cost-risk, but also user defined performance and schedule criteria. This implementation of full-trade study support contributes significantly to the realization of the integrated development environment. The process-based cost estimation model generates development and manufacturing cost estimates. The development team plans to expand the manufacturing process base from approximately 80 manufacturing processes to over 250 processes. Operation and support cost modeling is also envisioned. Process-based estimation considers the materials, resources, and processes in establishing cost-risk and rather depending on weight as an input, actually estimates weight along with cost and schedule.

An integrative cross-design synthesis approach to estimate the cost of illness: an applied case to the cost of depression in Catalonia.

PubMed

Bendeck, Murielle; Serrano-Blanco, Antoni; García-Alonso, Carlos; Bonet, Pere; Jordà, Esther; Sabes-Figuera, Ramon; Salvador-Carulla, Luis

2013-04-01

Cost of illness (COI) studies are carried out under conditions of uncertainty and with incomplete information. There are concerns regarding their generalisability, accuracy and usability in evidence-informed care. A hybrid methodology is used to estimate the regional costs of depression in Catalonia (Spain) following an integrative approach. The cross-design synthesis included nominal groups and quantitative analysis of both top-down and bottom-up studies, and incorporated primary and secondary data from different sources of information in Catalonia. Sensitivity analysis used probabilistic Monte Carlo simulation modelling. A dissemination strategy was planned, including a standard form adapted from cost-effectiveness studies to summarise methods and results. The method used allows for a comprehensive estimate of the cost of depression in Catalonia. Health officers and decision-makers concluded that this methodology provided useful information and knowledge for evidence-informed planning in mental health. The mix of methods, combined with a simulation model, contributed to a reduction in data gaps and, in conditions of uncertainty, supplied more complete information on the costs of depression in Catalonia. This approach to COI should be differentiated from other COI designs to allow like-with-like comparisons. A consensus on COI typology, procedures and dissemination is needed.

A Cost-Minimization Analysis of Tissue-Engineered Constructs for Corneal Endothelial Transplantation

PubMed Central

Tan, Tien-En; Peh, Gary S. L.; George, Benjamin L.; Cajucom-Uy, Howard Y.; Dong, Di; Finkelstein, Eric A.; Mehta, Jodhbir S.

2014-01-01

Corneal endothelial transplantation or endothelial keratoplasty has become the preferred choice of transplantation for patients with corneal blindness due to endothelial dysfunction. Currently, there is a worldwide shortage of transplantable tissue, and demand is expected to increase further with aging populations. Tissue-engineered alternatives are being developed, and are likely to be available soon. However, the cost of these constructs may impair their widespread use. A cost-minimization analysis comparing tissue-engineered constructs to donor tissue procured from eye banks for endothelial keratoplasty was performed. Both initial investment costs and recurring costs were considered in the analysis to arrive at a final tissue cost per transplant. The clinical outcomes of endothelial keratoplasty with tissue-engineered constructs and with donor tissue procured from eye banks were assumed to be equivalent. One-way and probabilistic sensitivity analyses were performed to simulate various possible scenarios, and to determine the robustness of the results. A tissue engineering strategy was cheaper in both investment cost and recurring cost. Tissue-engineered constructs for endothelial keratoplasty could be produced at a cost of US$880 per transplant. In contrast, utilizing donor tissue procured from eye banks for endothelial keratoplasty required US$3,710 per transplant. Sensitivity analyses performed further support the results of this cost-minimization analysis across a wide range of possible scenarios. The use of tissue-engineered constructs for endothelial keratoplasty could potentially increase the supply of transplantable tissue and bring the costs of corneal endothelial transplantation down, making this intervention accessible to a larger group of patients. Tissue-engineering strategies for corneal epithelial constructs or other tissue types, such as pancreatic islet cells, should also be subject to similar pharmacoeconomic analyses. PMID:24949869

Cost-effectiveness analysis of population-based tobacco control strategies in the prevention of cardiovascular diseases in Tanzania

PubMed Central

Ngalesoni, Frida; Ruhago, George; Mayige, Mary; Oliveira, Tiago Cravo; Robberstad, Bjarne; Norheim, Ole Frithjof; Higashi, Hideki

2017-01-01

Background Tobacco consumption contributes significantly to the global burden of disease. The prevalence of smoking is estimated to be increasing in many low-income countries, including Tanzania, especially among women and youth. Even so, the implementation of tobacco control measures has been discouraging in the country. Efforts to foster investment in tobacco control are hindered by lack of evidence on what works and at what cost. Aims We aim to estimate the cost and cost-effectiveness of population-based tobacco control strategies in the prevention of cardiovascular diseases (CVD) in Tanzania. Materials and methods A cost-effectiveness analysis was performed using an Excel-based Markov model, from a governmental perspective. We employed an ingredient approach and step-down methodologies in the costing exercise following a government perspective. Epidemiological data and efficacy inputs were derived from the literature. We used disability-adjusted life years (DALYs) averted as the outcome measure. A probabilistic sensitivity analysis was carried out with Ersatz to incorporate uncertainties in the model parameters. Results Our model results showed that all five tobacco control strategies were very cost-effective since they fell below the ceiling ratio of one GDP per capita suggested by the WHO. Increase in tobacco taxes was the most cost-effective strategy, while a workplace smoking ban was the least cost-effective option, with a cost-effectiveness ratio of US$5 and US$267, respectively. Conclusions Even though all five interventions are deemed very cost-effective in the prevention of CVD in Tanzania, more research on budget impact analysis is required to further assess the government’s ability to implement these interventions. PMID:28767722

Cost-Effectiveness Analysis of Stereotactic Body Radiation Therapy Compared With Radiofrequency Ablation for Inoperable Colorectal Liver Metastases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Hayeon, E-mail: kimh2@upmc.edu; Gill, Beant; Beriwal, Sushil

Purpose: To conduct a cost-effectiveness analysis to determine whether stereotactic body radiation therapy (SBRT) is a cost-effective therapy compared with radiofrequency ablation (RFA) for patients with unresectable colorectal cancer (CRC) liver metastases. Methods and Materials: A cost-effectiveness analysis was conducted using a Markov model and 1-month cycle over a lifetime horizon. Transition probabilities, quality of life utilities, and costs associated with SBRT and RFA were captured in the model on the basis of a comprehensive literature review and Medicare reimbursements in 2014. Strategies were compared using the incremental cost-effectiveness ratio, with effectiveness measured in quality-adjusted life years (QALYs). To account formore » model uncertainty, 1-way and probabilistic sensitivity analyses were performed. Strategies were evaluated with a willingness-to-pay threshold of $100,000 per QALY gained. Results: In base case analysis, treatment costs for 3 fractions of SBRT and 1 RFA procedure were $13,000 and $4397, respectively. Median survival was assumed the same for both strategies (25 months). The SBRT costs $8202 more than RFA while gaining 0.05 QALYs, resulting in an incremental cost-effectiveness ratio of $164,660 per QALY gained. In 1-way sensitivity analyses, results were most sensitive to variation of median survival from both treatments. Stereotactic body radiation therapy was economically reasonable if better survival was presumed (>1 month gain) or if used for large tumors (>4 cm). Conclusions: If equal survival is assumed, SBRT is not cost-effective compared with RFA for inoperable colorectal liver metastases. However, if better local control leads to small survival gains with SBRT, this strategy becomes cost-effective. Ideally, these results should be confirmed with prospective comparative data.« less

A cost-minimization analysis of tissue-engineered constructs for corneal endothelial transplantation.

PubMed

Tan, Tien-En; Peh, Gary S L; George, Benjamin L; Cajucom-Uy, Howard Y; Dong, Di; Finkelstein, Eric A; Mehta, Jodhbir S

2014-01-01

Corneal endothelial transplantation or endothelial keratoplasty has become the preferred choice of transplantation for patients with corneal blindness due to endothelial dysfunction. Currently, there is a worldwide shortage of transplantable tissue, and demand is expected to increase further with aging populations. Tissue-engineered alternatives are being developed, and are likely to be available soon. However, the cost of these constructs may impair their widespread use. A cost-minimization analysis comparing tissue-engineered constructs to donor tissue procured from eye banks for endothelial keratoplasty was performed. Both initial investment costs and recurring costs were considered in the analysis to arrive at a final tissue cost per transplant. The clinical outcomes of endothelial keratoplasty with tissue-engineered constructs and with donor tissue procured from eye banks were assumed to be equivalent. One-way and probabilistic sensitivity analyses were performed to simulate various possible scenarios, and to determine the robustness of the results. A tissue engineering strategy was cheaper in both investment cost and recurring cost. Tissue-engineered constructs for endothelial keratoplasty could be produced at a cost of US$880 per transplant. In contrast, utilizing donor tissue procured from eye banks for endothelial keratoplasty required US$3,710 per transplant. Sensitivity analyses performed further support the results of this cost-minimization analysis across a wide range of possible scenarios. The use of tissue-engineered constructs for endothelial keratoplasty could potentially increase the supply of transplantable tissue and bring the costs of corneal endothelial transplantation down, making this intervention accessible to a larger group of patients. Tissue-engineering strategies for corneal epithelial constructs or other tissue types, such as pancreatic islet cells, should also be subject to similar pharmacoeconomic analyses.

Cost-effectiveness of sacubitril/valsartan in chronic heart-failure patients with reduced ejection fraction.

PubMed

Ademi, Zanfina; Pfeil, Alena M; Hancock, Elizabeth; Trueman, David; Haroun, Rola Haroun; Deschaseaux, Celine; Schwenkglenks, Matthias

2017-11-29

We aimed to assess the cost effectiveness of sacubitril/valsartan compared to angiotensin-converting enzyme inhibitors (ACEIs) for the treatment of individuals with chronic heart failure and reduced-ejection fraction (HFrEF) from the perspective of the Swiss health care system. The cost-effectiveness analysis was implemented as a lifelong regression-based cohort model. We compared sacubitril/valsartan with enalapril in chronic heart failure patients with HFrEF and New York-Heart Association Functional Classification II-IV symptoms. Regression models based on the randomised clinical phase III PARADIGM-HF trials were used to predict events (all-cause mortality, hospitalisations, adverse events and quality of life) for each treatment strategy modelled over the lifetime horizon, with adjustments for patient characteristics. Unit costs were obtained from Swiss public sources for the year 2014, and costs and effects were discounted by 3%. The main outcome of interest was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life years (QALYs) gained. Deterministic sensitivity analysis (DSA) and scenario and probabilistic sensitivity analysis (PSA) were performed. In the base-case analysis, the sacubitril/valsartan strategy showed a decrease in the number of hospitalisations (6.0% per year absolute reduction) and lifetime hospital costs by 8.0% (discounted) when compared with enalapril. Sacubitril/valsartan was predicted to improve overall and quality-adjusted survival by 0.50 years and 0.42 QALYs, respectively. Additional net-total costs were CHF 10 926. This led to an ICER of CHF 25 684. In PSA, the probability of sacubitril/valsartan being cost-effective at thresholds of CHF 50 000 was 99.0%. The treatment of HFrEF patients with sacubitril/valsartan versus enalapril is cost effective, if a willingness-to-pay threshold of CHF 50 000 per QALY gained ratio is assumed.

Probabilistic Risk Assessment: A Bibliography

NASA Technical Reports Server (NTRS)

2000-01-01

Probabilistic risk analysis is an integration of failure modes and effects analysis (FMEA), fault tree analysis and other techniques to assess the potential for failure and to find ways to reduce risk. This bibliography references 160 documents in the NASA STI Database that contain the major concepts, probabilistic risk assessment, risk and probability theory, in the basic index or major subject terms, An abstract is included with most citations, followed by the applicable subject terms.

Probabilistic Sensitivity Analysis with Respect to Bounds of Truncated Distributions (PREPRINT)

DTIC Science & Technology

2010-04-01

AFRL-RX-WP-TP-2010-4147 PROBABILISTIC SENSITIVITY ANALYSIS WITH RESPECT TO BOUNDS OF TRUNCATED DISTRIBUTIONS (PREPRINT) H. Millwater and...5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) H. Millwater and Y. Feng 5d. PROJECT...Z39-18 1 Probabilistic Sensitivity Analysis with respect to Bounds of Truncated Distributions H. Millwater and Y. Feng Department of Mechanical

A probabilistic analysis of cumulative carbon emissions and long-term planetary warming

DOE PAGES

Fyke, Jeremy Garmeson; Matthews, H. Damon

2015-11-16

Efforts to mitigate and adapt to long-term climate change could benefit greatly from probabilistic estimates of cumulative carbon emissions due to fossil fuel burning and resulting CO 2-induced planetary warming. Here we demonstrate the use of a reduced-form model to project these variables. We performed simulations using a large-ensemble framework with parametric uncertainty sampled to produce distributions of future cumulative emissions and consequent planetary warming. A hind-cast ensemble of simulations captured 1980–2012 historical CO 2 emissions trends and an ensemble of future projection simulations generated a distribution of emission scenarios that qualitatively resembled the suite of Representative and Extended Concentrationmore » Pathways. The resulting cumulative carbon emission and temperature change distributions are characterized by 5–95th percentile ranges of 0.96–4.9 teratonnes C (Tt C) and 1.4 °C–8.5 °C, respectively, with 50th percentiles at 3.1 Tt C and 4.7 °C. Within the wide range of policy-related parameter combinations that produced these distributions, we found that low-emission simulations were characterized by both high carbon prices and low costs of non-fossil fuel energy sources, suggesting the importance of these two policy levers in particular for avoiding dangerous levels of climate warming. With this analysis we demonstrate a probabilistic approach to the challenge of identifying strategies for limiting cumulative carbon emissions and assessing likelihoods of surpassing dangerous temperature thresholds.« less

Cost-effectiveness Analysis in R Using a Multi-state Modeling Survival Analysis Framework: A Tutorial.

PubMed

Williams, Claire; Lewsey, James D; Briggs, Andrew H; Mackay, Daniel F

2017-05-01

This tutorial provides a step-by-step guide to performing cost-effectiveness analysis using a multi-state modeling approach. Alongside the tutorial, we provide easy-to-use functions in the statistics package R. We argue that this multi-state modeling approach using a package such as R has advantages over approaches where models are built in a spreadsheet package. In particular, using a syntax-based approach means there is a written record of what was done and the calculations are transparent. Reproducing the analysis is straightforward as the syntax just needs to be run again. The approach can be thought of as an alternative way to build a Markov decision-analytic model, which also has the option to use a state-arrival extended approach. In the state-arrival extended multi-state model, a covariate that represents patients' history is included, allowing the Markov property to be tested. We illustrate the building of multi-state survival models, making predictions from the models and assessing fits. We then proceed to perform a cost-effectiveness analysis, including deterministic and probabilistic sensitivity analyses. Finally, we show how to create 2 common methods of visualizing the results-namely, cost-effectiveness planes and cost-effectiveness acceptability curves. The analysis is implemented entirely within R. It is based on adaptions to functions in the existing R package mstate to accommodate parametric multi-state modeling that facilitates extrapolation of survival curves.

The Cost-Effectiveness of Surgical Fixation of Distal Radial Fractures: A Computer Model-Based Evaluation of Three Operative Modalities.

PubMed

Rajan, Prashant V; Qudsi, Rameez A; Dyer, George S M; Losina, Elena

2018-02-07

There is no consensus on the optimal fixation method for patients who require a surgical procedure for distal radial fractures. We used cost-effectiveness analyses to determine which of 3 modalities offers the best value: closed reduction and percutaneous pinning, open reduction and internal fixation, or external fixation. We developed a Markov model that projected short-term and long-term health benefits and costs in patients undergoing a surgical procedure for a distal radial fracture. Simulations began at the patient age of 50 years and were run over the patient's lifetime. The analysis was conducted from health-care payer and societal perspectives. We estimated transition probabilities and quality-of-life values from the literature and determined costs from Medicare reimbursement schedules in 2016 U.S. dollars. Suboptimal postoperative outcomes were determined by rates of reduction loss (4% for closed reduction and percutaneous pinning, 1% for open reduction and internal fixation, and 11% for external fixation) and rates of orthopaedic complications. Procedural costs were $7,638 for closed reduction and percutaneous pinning, $10,170 for open reduction and internal fixation, and $9,886 for external fixation. Outputs were total costs and quality-adjusted life-years (QALYs), discounted at 3% per year. We considered willingness-to-pay thresholds of $50,000 and $100,000. We conducted deterministic and probabilistic sensitivity analyses to evaluate the impact of data uncertainty. From the health-care payer perspective, closed reduction and percutaneous pinning dominated (i.e., produced greater QALYs at lower costs than) open reduction and internal fixation and dominated external fixation. From the societal perspective, the incremental cost-effectiveness ratio for closed reduction and percutaneous pinning compared with open reduction and internal fixation was $21,058 per QALY and external fixation was dominated. In probabilistic sensitivity analysis, open reduction and internal fixation was cost-effective roughly 50% of the time compared with roughly 45% for closed reduction and percutaneous pinning. When considering data uncertainty, there is only a 5% to 10% difference in the frequency of probability combinations that find open reduction and internal fixation to be more cost-effective. The current degree of uncertainty in the data produces difficulty in distinguishing either strategy as being more cost-effective overall and thus it may be left to surgeon and patient shared decision-making. Economic Level III. See Instructions for Authors for a complete description of levels of evidence.

Analyzing cost-effectiveness of ulnar and median nerve transfers to regain forearm flexion.

PubMed

Wali, Arvin R; Park, Charlie C; Brown, Justin M; Mandeville, Ross

2017-03-01

OBJECTIVE Peripheral nerve transfers to regain elbow flexion via the ulnar nerve (Oberlin nerve transfer) and median nerves are surgical options that benefit patients. Prior studies have assessed the comparative effectiveness of ulnar and median nerve transfers for upper trunk brachial plexus injury, yet no study has examined the cost-effectiveness of this surgery to improve quality-adjusted life years (QALYs). The authors present a cost-effectiveness model of the Oberlin nerve transfer and median nerve transfer to restore elbow flexion in the adult population with upper brachial plexus injury. METHODS Using a Markov model, the authors simulated ulnar and median nerve transfers and conservative measures in terms of neurological recovery and improvements in quality of life (QOL) for patients with upper brachial plexus injury. Transition probabilities were collected from previous studies that assessed the surgical efficacy of ulnar and median nerve transfers, complication rates associated with comparable surgical interventions, and the natural history of conservative measures. Incremental cost-effectiveness ratios (ICERs), defined as cost in dollars per QALY, were calculated. Incremental cost-effectiveness ratios less than $50,000/QALY were considered cost-effective. One-way and 2-way sensitivity analyses were used to assess parameter uncertainty. Probabilistic sampling was used to assess ranges of outcomes across 100,000 trials. RESULTS The authors' base-case model demonstrated that ulnar and median nerve transfers, with an estimated cost of $5066.19, improved effectiveness by 0.79 QALY over a lifetime compared with conservative management. Without modeling the indirect cost due to loss of income over lifetime associated with elbow function loss, surgical treatment had an ICER of $6453.41/QALY gained. Factoring in the loss of income as indirect cost, surgical treatment had an ICER of -$96,755.42/QALY gained, demonstrating an overall lifetime cost savings due to increased probability of returning to work. One-way sensitivity analysis demonstrated that the model was most sensitive to assumptions about cost of surgery, probability of good surgical outcome, and spontaneous recovery of neurological function with conservative treatment. Two-way sensitivity analysis demonstrated that surgical intervention was cost-effective with an ICER of $18,828.06/QALY even with the authors' most conservative parameters with surgical costs at $50,000 and probability of success of 50% when considering the potential income recovered through returning to work. Probabilistic sampling demonstrated that surgical intervention was cost-effective in 76% of cases at a willingness-to-pay threshold of $50,000/QALY gained. CONCLUSIONS The authors' model demonstrates that ulnar and median nerve transfers for upper brachial plexus injury improves QALY in a cost-effective manner.

A probabilistic Hu-Washizu variational principle

NASA Technical Reports Server (NTRS)

Liu, W. K.; Belytschko, T.; Besterfield, G. H.

1987-01-01

A Probabilistic Hu-Washizu Variational Principle (PHWVP) for the Probabilistic Finite Element Method (PFEM) is presented. This formulation is developed for both linear and nonlinear elasticity. The PHWVP allows incorporation of the probabilistic distributions for the constitutive law, compatibility condition, equilibrium, domain and boundary conditions into the PFEM. Thus, a complete probabilistic analysis can be performed where all aspects of the problem are treated as random variables and/or fields. The Hu-Washizu variational formulation is available in many conventional finite element codes thereby enabling the straightforward inclusion of the probabilistic features into present codes.

Cost-Benefit Analysis of a Support Program for Nursing Staff.

PubMed

Moran, Dane; Wu, Albert W; Connors, Cheryl; Chappidi, Meera R; Sreedhara, Sushama K; Selter, Jessica H; Padula, William V

2017-04-27

A peer-support program called Resilience In Stressful Events (RISE) was designed to help hospital staff cope with stressful patient-related events. The aim of this study was to evaluate the impact of the RISE program by conducting an economic evaluation of its cost benefit. A Markov model with a 1-year time horizon was developed to compare the cost benefit with and without the RISE program from a provider (hospital) perspective. Nursing staff who used the RISE program between 2015 and 2016 at a 1000-bed, private hospital in the United States were included in the analysis. The cost of running the RISE program, nurse turnover, and nurse time off were modeled. Data on costs were obtained from literature review and hospital data. Probabilities of quitting or taking time off with or without the RISE program were estimated using survey data. Net monetary benefit (NMB) and budget impact of having the RISE program were computed to determine cost benefit to the hospital. Expected model results of the RISE program found a net monetary benefit savings of US $22,576.05 per nurse who initiated a RISE call. These savings were determined to be 99.9% consistent on the basis of a probabilistic sensitivity analysis. The budget impact analysis revealed that a hospital could save US $1.81 million each year because of the RISE program. The RISE program resulted in substantial cost savings to the hospital. Hospitals should be encouraged by these findings to implement institution-wide support programs for medical staff, based on a high demand for this type of service and the potential for cost savings.

Specifying design conservatism: Worst case versus probabilistic analysis

NASA Technical Reports Server (NTRS)

Miles, Ralph F., Jr.

1993-01-01

Design conservatism is the difference between specified and required performance, and is introduced when uncertainty is present. The classical approach of worst-case analysis for specifying design conservatism is presented, along with the modern approach of probabilistic analysis. The appropriate degree of design conservatism is a tradeoff between the required resources and the probability and consequences of a failure. A probabilistic analysis properly models this tradeoff, while a worst-case analysis reveals nothing about the probability of failure, and can significantly overstate the consequences of failure. Two aerospace examples will be presented that illustrate problems that can arise with a worst-case analysis.

Probabilistic sharing solves the problem of costly punishment

NASA Astrophysics Data System (ADS)

Chen, Xiaojie; Szolnoki, Attila; Perc, Matjaž

2014-08-01

Cooperators that refuse to participate in sanctioning defectors create the second-order free-rider problem. Such cooperators will not be punished because they contribute to the public good, but they also eschew the costs associated with punishing defectors. Altruistic punishers—those that cooperate and punish—are at a disadvantage, and it is puzzling how such behaviour has evolved. We show that sharing the responsibility to sanction defectors rather than relying on certain individuals to do so permanently can solve the problem of costly punishment. Inspired by the fact that humans have strong but also emotional tendencies for fair play, we consider probabilistic sanctioning as the simplest way of distributing the duty. In well-mixed populations the public goods game is transformed into a coordination game with full cooperation and defection as the two stable equilibria, while in structured populations pattern formation supports additional counterintuitive solutions that are reminiscent of Parrondo's paradox.

The cost-effectiveness of immediate treatment or watch and wait with deferred chemotherapy for advanced asymptomatic follicular lymphoma.

PubMed

Prettyjohns, Matthew; Hoskin, Peter; McNamara, Christopher; Linch, David

2018-01-01

Recent evidence has shown that immediate treatment with rituximab induction, with and without maintenance, substantially reduces the need for further treatment in patients with advanced asymptomatic follicular lymphoma. This analysis estimates the cost-effectiveness of immediate treatment approaches in comparison to a watch and wait approach from the perspective of the UK National Health Service. A Markov decision model was developed to estimate the cost-effectiveness of treatment strategies in patients with asymptomatic follicular lymphoma. The model was populated using effectiveness data from a systematic literature review with the key clinical data sourced from a randomised trial, in which the treatment strategies were compared. Costs were estimated using UK national sources. In comparison to watchful waiting, both rituximab strategies were found to be more effective and cost saving. In comparison to rituximab induction, the addition of rituximab maintenance marginally increased effectiveness but substantially increased costs, resulting in an incremental cost-effectiveness ratio (ICER) of £69 406 per quality-adjusted life year (QALY). In probabilistic sensitivity analysis, rituximab induction was found to have a 68% probability of being cost-effective at a threshold of £20 000 per QALY. In conclusion, active treatment with rituximab induction is a cost-effective strategy to adopt in patients with asymptomatic follicular lymphoma. © 2017 John Wiley & Sons Ltd.

Life Predicted in a Probabilistic Design Space for Brittle Materials With Transient Loads

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Palfi, Tamas; Reh, Stefan

2005-01-01

Analytical techniques have progressively become more sophisticated, and now we can consider the probabilistic nature of the entire space of random input variables on the lifetime reliability of brittle structures. This was demonstrated with NASA s CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code combined with the commercially available ANSYS/Probabilistic Design System (ANSYS/PDS), a probabilistic analysis tool that is an integral part of the ANSYS finite-element analysis program. ANSYS/PDS allows probabilistic loads, component geometry, and material properties to be considered in the finite-element analysis. CARES/Life predicts the time dependent probability of failure of brittle material structures under generalized thermomechanical loading--such as that found in a turbine engine hot-section. Glenn researchers coupled ANSYS/PDS with CARES/Life to assess the effects of the stochastic variables of component geometry, loading, and material properties on the predicted life of the component for fully transient thermomechanical loading and cyclic loading.

Heart failure disease management programs: a cost-effectiveness analysis.

PubMed

Chan, David C; Heidenreich, Paul A; Weinstein, Milton C; Fonarow, Gregg C

2008-02-01

Heart failure (HF) disease management programs have shown impressive reductions in hospitalizations and mortality, but in studies limited to short time frames and high-risk patient populations. Current guidelines thus only recommend disease management targeted to high-risk patients with HF. This study applied a new technique to infer the degree to which clinical trials have targeted patients by risk based on observed rates of hospitalization and death. A Markov model was used to assess the incremental life expectancy and cost of providing disease management for high-risk to low-risk patients. Sensitivity analyses of various long-term scenarios and of reduced effectiveness in low-risk patients were also considered. The incremental cost-effectiveness ratio of extending coverage to all patients was $9700 per life-year gained in the base case. In aggregate, universal coverage almost quadrupled life-years saved as compared to coverage of only the highest quintile of risk. A worst case analysis with simultaneous conservative assumptions yielded an incremental cost-effectiveness ratio of $110,000 per life-year gained. In a probabilistic sensitivity analysis, 99.74% of possible incremental cost-effectiveness ratios were <$50,000 per life-year gained. Heart failure disease management programs are likely cost-effective in the long-term along the whole spectrum of patient risk. Health gains could be extended by enrolling a broader group of patients with HF in disease management.

Photovoltaic venture analysis. Final report. Volume I. Executive summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costello, D.; Posner, D.; Schiffel, D.

1978-07-01

The objective of the study, government programs under investigation, and a brief review of the approach are presented. Potential markets for photovoltaic systems relevant to the study are described. The response of the photovoltaic supply industry is then considered. A model which integrates the supply and demand characteristics of photovoltaics over time was developed. This model also calculates the economic benefits associated with various government subsidy programs. Results are derived under alternative possible supply, demand, and macroeconomic conditions. A probabilistic analysis of the costs and benefits of a $380 million federal photovoltaic procurement initiative, as well as certain alternative strategies,more » is summarized. Conclusions and recommendations based on the analysis are presented.« less

Modeling Uncertainties in EEG Microstates: Analysis of Real and Imagined Motor Movements Using Probabilistic Clustering-Driven Training of Probabilistic Neural Networks.

PubMed

Dinov, Martin; Leech, Robert

2017-01-01

Part of the process of EEG microstate estimation involves clustering EEG channel data at the global field power (GFP) maxima, very commonly using a modified K-means approach. Clustering has also been done deterministically, despite there being uncertainties in multiple stages of the microstate analysis, including the GFP peak definition, the clustering itself and in the post-clustering assignment of microstates back onto the EEG timecourse of interest. We perform a fully probabilistic microstate clustering and labeling, to account for these sources of uncertainty using the closest probabilistic analog to KM called Fuzzy C-means (FCM). We train softmax multi-layer perceptrons (MLPs) using the KM and FCM-inferred cluster assignments as target labels, to then allow for probabilistic labeling of the full EEG data instead of the usual correlation-based deterministic microstate label assignment typically used. We assess the merits of the probabilistic analysis vs. the deterministic approaches in EEG data recorded while participants perform real or imagined motor movements from a publicly available data set of 109 subjects. Though FCM group template maps that are almost topographically identical to KM were found, there is considerable uncertainty in the subsequent assignment of microstate labels. In general, imagined motor movements are less predictable on a time point-by-time point basis, possibly reflecting the more exploratory nature of the brain state during imagined, compared to during real motor movements. We find that some relationships may be more evident using FCM than using KM and propose that future microstate analysis should preferably be performed probabilistically rather than deterministically, especially in situations such as with brain computer interfaces, where both training and applying models of microstates need to account for uncertainty. Probabilistic neural network-driven microstate assignment has a number of advantages that we have discussed, which are likely to be further developed and exploited in future studies. In conclusion, probabilistic clustering and a probabilistic neural network-driven approach to microstate analysis is likely to better model and reveal details and the variability hidden in current deterministic and binarized microstate assignment and analyses.

Modeling Uncertainties in EEG Microstates: Analysis of Real and Imagined Motor Movements Using Probabilistic Clustering-Driven Training of Probabilistic Neural Networks

PubMed Central

Dinov, Martin; Leech, Robert

2017-01-01

Part of the process of EEG microstate estimation involves clustering EEG channel data at the global field power (GFP) maxima, very commonly using a modified K-means approach. Clustering has also been done deterministically, despite there being uncertainties in multiple stages of the microstate analysis, including the GFP peak definition, the clustering itself and in the post-clustering assignment of microstates back onto the EEG timecourse of interest. We perform a fully probabilistic microstate clustering and labeling, to account for these sources of uncertainty using the closest probabilistic analog to KM called Fuzzy C-means (FCM). We train softmax multi-layer perceptrons (MLPs) using the KM and FCM-inferred cluster assignments as target labels, to then allow for probabilistic labeling of the full EEG data instead of the usual correlation-based deterministic microstate label assignment typically used. We assess the merits of the probabilistic analysis vs. the deterministic approaches in EEG data recorded while participants perform real or imagined motor movements from a publicly available data set of 109 subjects. Though FCM group template maps that are almost topographically identical to KM were found, there is considerable uncertainty in the subsequent assignment of microstate labels. In general, imagined motor movements are less predictable on a time point-by-time point basis, possibly reflecting the more exploratory nature of the brain state during imagined, compared to during real motor movements. We find that some relationships may be more evident using FCM than using KM and propose that future microstate analysis should preferably be performed probabilistically rather than deterministically, especially in situations such as with brain computer interfaces, where both training and applying models of microstates need to account for uncertainty. Probabilistic neural network-driven microstate assignment has a number of advantages that we have discussed, which are likely to be further developed and exploited in future studies. In conclusion, probabilistic clustering and a probabilistic neural network-driven approach to microstate analysis is likely to better model and reveal details and the variability hidden in current deterministic and binarized microstate assignment and analyses. PMID:29163110

A cost-minimisation analysis comparing photoselective vaporisation (PVP) and transurethral resection of the prostate (TURP) for the management of symptomatic benign prostatic hyperplasia (BPH) in Queensland, Australia.

PubMed

Whitty, Jennifer A; Crosland, Paul; Hewson, Kaye; Narula, Rajan; Nathan, Timothy R; Campbell, Peter A; Keller, Andrew; Scuffham, Paul A

2014-03-01

To compare the costs of photoselective vaporisation (PVP) and transurethral resection of the prostate (TURP) for management of symptomatic benign prostatic hyperplasia (BPH) from the perspective of a Queensland public hospital provider. A decision-analytic model was used to compare the costs of PVP and TURP. Cost inputs were sourced from an audit of patients undergoing PVP or TURP across three hospitals. The probability of re-intervention was obtained from secondary literature sources. Probabilistic and multi-way sensitivity analyses were used to account for uncertainty and test the impact of varying key assumptions. In the base case analysis, which included equipment, training and re-intervention costs, PVP was AU$ 739 (95% credible interval [CrI] -12 187 to 14 516) more costly per patient than TURP. The estimate was most sensitive to changes in procedural costs, fibre costs and the probability of re-intervention. Sensitivity analyses based on data from the most favourable site or excluding equipment and training costs reduced the point estimate to favour PVP (incremental cost AU$ -684, 95% CrI -8319 to 5796 and AU$ -100, 95% CrI -13 026 to 13 678, respectively). However, CrIs were wide for all analyses. In this cost minimisation analysis, there was no significant cost difference between PVP and TURP, after accounting for equipment, training and re-intervention costs. However, PVP was associated with a shorter length of stay and lower procedural costs during audit, indicating PVP potentially provides comparatively good value for money once the technology is established. © 2013 The Authors. BJU International © 2013 BJU International.

A Case Study for Probabilistic Methods Validation (MSFC Center Director's Discretionary Fund, Project No. 94-26)

NASA Technical Reports Server (NTRS)

Price J. M.; Ortega, R.

1998-01-01

Probabilistic method is not a universally accepted approach for the design and analysis of aerospace structures. The validity of this approach must be demonstrated to encourage its acceptance as it viable design and analysis tool to estimate structural reliability. The objective of this Study is to develop a well characterized finite population of similar aerospace structures that can be used to (1) validate probabilistic codes, (2) demonstrate the basic principles behind probabilistic methods, (3) formulate general guidelines for characterization of material drivers (such as elastic modulus) when limited data is available, and (4) investigate how the drivers affect the results of sensitivity analysis at the component/failure mode level.

A Comparison of Probabilistic and Deterministic Campaign Analysis for Human Space Exploration

NASA Technical Reports Server (NTRS)

Merrill, R. Gabe; Andraschko, Mark; Stromgren, Chel; Cirillo, Bill; Earle, Kevin; Goodliff, Kandyce

2008-01-01

Human space exploration is by its very nature an uncertain endeavor. Vehicle reliability, technology development risk, budgetary uncertainty, and launch uncertainty all contribute to stochasticity in an exploration scenario. However, traditional strategic analysis has been done in a deterministic manner, analyzing and optimizing the performance of a series of planned missions. History has shown that exploration scenarios rarely follow such a planned schedule. This paper describes a methodology to integrate deterministic and probabilistic analysis of scenarios in support of human space exploration. Probabilistic strategic analysis is used to simulate "possible" scenario outcomes, based upon the likelihood of occurrence of certain events and a set of pre-determined contingency rules. The results of the probabilistic analysis are compared to the nominal results from the deterministic analysis to evaluate the robustness of the scenario to adverse events and to test and optimize contingency planning.

Development and application of a probabilistic method for wildfire suppression cost modeling

Treesearch

Matthew P. Thompson; Jessica R. Haas; Mark A. Finney; David E. Calkin; Michael S. Hand; Mark J. Browne; Martin Halek; Karen C. Short; Isaac C. Grenfell

2015-01-01

Wildfire activity and escalating suppression costs continue to threaten the financial health of federal land management agencies. In order to minimize and effectively manage the cost of financial risk, agencies need the ability to quantify that risk. A fundamental aim of this research effort, therefore, is to develop a process for generating risk-based metrics for...

[Cost-effectiveness Analysis of Panitumumab Plus mFOLFOX6 Compared to Bevacizumab Plus mFOLFOX6 for First-line Treatment of Patients with Wild-type RAS Metastatic Colorectal Cancer--Czech Republic Model Adaptation].

PubMed

Fínek, J; Skoupá, J; Jandová, P

2015-01-01

Pharmacoeconomic assessments are a part of the decision process not only during reimbursement setting, but in clinical practice as well. The presented cost-effectiveness analysis assesses panitumumab+mFOLFOX6 vs. bevacizumab+mFOLFOX6 in 1st line treatment of patients with wildtype RAS metastatic colorectal cancer (mCRC) in the Czech environment. The adaptation of a Markov model considers the healthcare perspective; clinical data (efficacy, healthcare utilization and adverse events) are derived from a head-to-head comparison (PEAK study). Health states included in the model: progression free on treatment, progression (with/ without active treatment), resection of metastases, disease-free after successful resection and death. Actual reimbursement levels were used to estimate costs, published literature to estimate duration of 2nd line treatment. The analysis assumes a lifetime horizon; uncertainty was limited by performing one-way and probabilistic sensitivity analyses. Analysis outcomes are life-years gained (LYG) and quality-adjusted life-years (QALYs). Panitumumab+mFOLFOX6 is more effective and more costly in 1st line patients with wildtype RAS mCRC. Incremental costs per QALY are 837,270 CZK, per LYG 615,022 CZK; however, below the willingness-to-pay threshold applied in the Czech Republic. Panitumumab+mFOLFOX6 is cost-effective in 1st line treatment of patients with wildtype RAS mCRC compared to bevacizumab+mFOLFOX6 in the Czech setting.

Probabilistic Aeroelastic Analysis Developed for Turbomachinery Components

NASA Technical Reports Server (NTRS)

Reddy, T. S. R.; Mital, Subodh K.; Stefko, George L.; Pai, Shantaram S.

2003-01-01

Aeroelastic analyses for advanced turbomachines are being developed for use at the NASA Glenn Research Center and industry. However, these analyses at present are used for turbomachinery design with uncertainties accounted for by using safety factors. This approach may lead to overly conservative designs, thereby reducing the potential of designing higher efficiency engines. An integration of the deterministic aeroelastic analysis methods with probabilistic analysis methods offers the potential to design efficient engines with fewer aeroelastic problems and to make a quantum leap toward designing safe reliable engines. In this research, probabilistic analysis is integrated with aeroelastic analysis: (1) to determine the parameters that most affect the aeroelastic characteristics (forced response and stability) of a turbomachine component such as a fan, compressor, or turbine and (2) to give the acceptable standard deviation on the design parameters for an aeroelastically stable system. The approach taken is to combine the aeroelastic analysis of the MISER (MIStuned Engine Response) code with the FPI (fast probability integration) code. The role of MISER is to provide the functional relationships that tie the structural and aerodynamic parameters (the primitive variables) to the forced response amplitudes and stability eigenvalues (the response properties). The role of FPI is to perform probabilistic analyses by utilizing the response properties generated by MISER. The results are a probability density function for the response properties. The probabilistic sensitivities of the response variables to uncertainty in primitive variables are obtained as a byproduct of the FPI technique. The combined analysis of aeroelastic and probabilistic analysis is applied to a 12-bladed cascade vibrating in bending and torsion. Out of the total 11 design parameters, 6 are considered as having probabilistic variation. The six parameters are space-to-chord ratio (SBYC), stagger angle (GAMA), elastic axis (ELAXS), Mach number (MACH), mass ratio (MASSR), and frequency ratio (WHWB). The cascade is considered to be in subsonic flow with Mach 0.7. The results of the probabilistic aeroelastic analysis are the probability density function of predicted aerodynamic damping and frequency for flutter and the response amplitudes for forced response.

A Cost-effectiveness Analysis of Early vs Late Tracheostomy.

PubMed

Liu, C Carrie; Rudmik, Luke

2016-10-01

The timing of tracheostomy in critically ill patients requiring mechanical ventilation is controversial. An important consideration that is currently missing in the literature is an evaluation of the economic impact of an early tracheostomy strategy vs a late tracheostomy strategy. To evaluate the cost-effectiveness of the early tracheostomy strategy vs the late tracheostomy strategy. This economic analysis was performed using a decision tree model with a 90-day time horizon. The economic perspective was that of the US health care third-party payer. The primary outcome was the incremental cost per tracheostomy avoided. Probabilities were obtained from meta-analyses of randomized clinical trials. Costs were obtained from the published literature and the Healthcare Cost and Utilization Project database. A multivariate probabilistic sensitivity analysis was performed to account for uncertainty surrounding mean values used in the reference case. The reference case demonstrated that the cost of the late tracheostomy strategy was $45 943.81 for 0.36 of effectiveness. The cost of the early tracheostomy strategy was $31 979.12 for 0.19 of effectiveness. The incremental cost-effectiveness ratio for the late tracheostomy strategy compared with the early tracheostomy strategy was $82 145.24 per tracheostomy avoided. With a willingness-to-pay threshold of $50 000, the early tracheostomy strategy is cost-effective with 56% certainty. The adaptation of an early vs a late tracheostomy strategy depends on the priorities of the decision-maker. Up to a willingness-to-pay threshold of $80 000 per tracheostomy avoided, the early tracheostomy strategy has a higher probability of being the more cost-effective intervention.

Surveillance-guided selective digestive decontamination of carbapenem-resistant Enterobacteriaceae in the intensive care unit: A cost-effectiveness analysis.

PubMed

You, Joyce H S; Li, Hong-Kiu; Ip, Margaret

2018-03-01

Clinical findings have shown effectiveness and safety of selective digestive decontamination (SDD) for eradication of carbapenem-resistant Enterobacteriaceae (CRE) in high-risk carriers. We aimed to evaluate the cost-effectiveness of SDD guided by CRE surveillance in the intensive care unit (ICU). Outcomes of surveillance-guided SDD (test-guided SDD) and no screening (control) in the ICU were compared by Markov model simulations. Model outcomes were CRE infection and mortality rates, direct costs, and quality-adjusted life year (QALY) loss. Model inputs were estimated from clinical literature. Sensitivity analyses were conducted to examine the robustness of base case results. Test-guided SDD reduced infection (4.8% vs 5.0%) and mortality (1.8% vs 2.1%) rates at a higher cost ($1,102 vs $1,074) than the control group in base case analysis, respectively. Incremental cost per QALY saved (incremental cost-effectiveness ratio [ICER]) by the test-guided SDD group was $557 per QALY. Probabilistic sensitivity analysis showed that test-guided SDD was effective in saving QALYs in 100% of 10,000 Monte Carlo simulations, and cost-saving 59.1% of time. The remaining 40.9% of simulations found SDD to be effective at an additional cost, with ICERs accepted as cost-effective per the willingness-to-pay threshold. Surveillance-guided SDD appears to be cost-effective in reducing CRE infection and mortality with QALYs saved. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Cost-effectiveness of available treatment options for patients suffering from severe COPD in the UK: a fully incremental analysis.

PubMed

Hertel, Nadine; Kotchie, Robert W; Samyshkin, Yevgeniy; Radford, Matthew; Humphreys, Samantha; Jameson, Kevin

2012-01-01

Frequent exacerbations which are both costly and potentially life-threatening are a major concern to patients with chronic obstructive pulmonary disease (COPD), despite the availability of several treatment options. This study aimed to assess the lifetime costs and outcomes associated with alternative treatment regimens for patients with severe COPD in the UK setting. A Markov cohort model was developed to predict lifetime costs, outcomes, and cost-effectiveness of various combinations of a long-acting muscarinic antagonist (LAMA), a long-acting beta agonist (LABA), an inhaled corticosteroid (ICS), and roflumilast in a fully incremental analysis. Patients willing and able to take ICS, and those refusing or intolerant to ICS were analyzed separately. Efficacy was expressed as relative rate ratios of COPD exacerbation associated with alternative treatment regimens, taken from a mixed treatment comparison. The analysis was conducted from the UK National Health Service (NHS) perspective. Parameter uncertainty was explored using one-way and probabilistic sensitivity analysis. Based on the results of the fully incremental analysis a cost-effectiveness frontier was determined, indicating those treatment regimens which represent the most cost-effective use of NHS resources. For ICS-tolerant patients the cost-effectiveness frontier suggested LAMA as initial treatment. Where patients continue to exacerbate and additional therapy is required, LAMA + LABA/ICS can be a cost-effective option, followed by LAMA + LABA/ICS + roflumilast (incremental cost-effectiveness ratio [ICER] versus LAMA + LABA/ICS: £16,566 per quality-adjusted life-year [QALY] gained). The ICER in ICS-intolerant patients, comparing LAMA + LABA + roflumilast versus LAMA + LABA, was £13,764/QALY gained. The relative rate ratio of exacerbations was identified as the primary driver of cost-effectiveness. The treatment algorithm recommended in UK clinical practice represents a cost-effective approach for the management of COPD. The addition of roflumilast to the standard of care regimens is a clinical and cost-effective treatment option for patients with severe COPD, who continue to exacerbate despite existing bronchodilator therapy.

Global/local methods for probabilistic structural analysis

NASA Technical Reports Server (NTRS)

Millwater, H. R.; Wu, Y.-T.

1993-01-01

A probabilistic global/local method is proposed to reduce the computational requirements of probabilistic structural analysis. A coarser global model is used for most of the computations with a local more refined model used only at key probabilistic conditions. The global model is used to establish the cumulative distribution function (cdf) and the Most Probable Point (MPP). The local model then uses the predicted MPP to adjust the cdf value. The global/local method is used within the advanced mean value probabilistic algorithm. The local model can be more refined with respect to the g1obal model in terms of finer mesh, smaller time step, tighter tolerances, etc. and can be used with linear or nonlinear models. The basis for this approach is described in terms of the correlation between the global and local models which can be estimated from the global and local MPPs. A numerical example is presented using the NESSUS probabilistic structural analysis program with the finite element method used for the structural modeling. The results clearly indicate a significant computer savings with minimal loss in accuracy.

Global/local methods for probabilistic structural analysis

NASA Astrophysics Data System (ADS)

Millwater, H. R.; Wu, Y.-T.

1993-04-01

A probabilistic global/local method is proposed to reduce the computational requirements of probabilistic structural analysis. A coarser global model is used for most of the computations with a local more refined model used only at key probabilistic conditions. The global model is used to establish the cumulative distribution function (cdf) and the Most Probable Point (MPP). The local model then uses the predicted MPP to adjust the cdf value. The global/local method is used within the advanced mean value probabilistic algorithm. The local model can be more refined with respect to the g1obal model in terms of finer mesh, smaller time step, tighter tolerances, etc. and can be used with linear or nonlinear models. The basis for this approach is described in terms of the correlation between the global and local models which can be estimated from the global and local MPPs. A numerical example is presented using the NESSUS probabilistic structural analysis program with the finite element method used for the structural modeling. The results clearly indicate a significant computer savings with minimal loss in accuracy.

Structural reliability methods: Code development status

NASA Astrophysics Data System (ADS)

Millwater, Harry R.; Thacker, Ben H.; Wu, Y.-T.; Cruse, T. A.

1991-05-01

The Probabilistic Structures Analysis Method (PSAM) program integrates state of the art probabilistic algorithms with structural analysis methods in order to quantify the behavior of Space Shuttle Main Engine structures subject to uncertain loadings, boundary conditions, material parameters, and geometric conditions. An advanced, efficient probabilistic structural analysis software program, NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) was developed as a deliverable. NESSUS contains a number of integrated software components to perform probabilistic analysis of complex structures. A nonlinear finite element module NESSUS/FEM is used to model the structure and obtain structural sensitivities. Some of the capabilities of NESSUS/FEM are shown. A Fast Probability Integration module NESSUS/FPI estimates the probability given the structural sensitivities. A driver module, PFEM, couples the FEM and FPI. NESSUS, version 5.0, addresses component reliability, resistance, and risk.

Structural reliability methods: Code development status

NASA Technical Reports Server (NTRS)

Millwater, Harry R.; Thacker, Ben H.; Wu, Y.-T.; Cruse, T. A.

1991-01-01

The Probabilistic Structures Analysis Method (PSAM) program integrates state of the art probabilistic algorithms with structural analysis methods in order to quantify the behavior of Space Shuttle Main Engine structures subject to uncertain loadings, boundary conditions, material parameters, and geometric conditions. An advanced, efficient probabilistic structural analysis software program, NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) was developed as a deliverable. NESSUS contains a number of integrated software components to perform probabilistic analysis of complex structures. A nonlinear finite element module NESSUS/FEM is used to model the structure and obtain structural sensitivities. Some of the capabilities of NESSUS/FEM are shown. A Fast Probability Integration module NESSUS/FPI estimates the probability given the structural sensitivities. A driver module, PFEM, couples the FEM and FPI. NESSUS, version 5.0, addresses component reliability, resistance, and risk.

Reconciling uncertain costs and benefits in bayes nets for invasive species management

USGS Publications Warehouse

Burgman, M.A.; Wintle, B.A.; Thompson, C.A.; Moilanen, A.; Runge, M.C.; Ben-Haim, Y.

2010-01-01

Bayes nets are used increasingly to characterize environmental systems and formalize probabilistic reasoning to support decision making. These networks treat probabilities as exact quantities. Sensitivity analysis can be used to evaluate the importance of assumptions and parameter estimates. Here, we outline an application of info-gap theory to Bayes nets that evaluates the sensitivity of decisions to possibly large errors in the underlying probability estimates and utilities. We apply it to an example of management and eradication of Red Imported Fire Ants in Southern Queensland, Australia and show how changes in management decisions can be justified when uncertainty is considered. ?? 2009 Society for Risk Analysis.

Kiovig for primary immunodeficiency: reduced infusion and decreased costs per infusion.

PubMed

Connolly, Mark; Simoens, Steven

2011-09-01

Kiovig is a ready-to-use 10% liquid immunoglobulin preparation that is medically indicated for the treatment of primary immunodeficiency. This study aims to conduct an economic evaluation which compares the intravenous immunoglobulin (IVIg) preparations Kiovig, Multigam, and Sandoglobulin from the Belgian societal perspective. As three prospective studies have observed no difference in outcomes, a cost-minimization analysis is considered appropriate to evaluate differences in treatment costs that can arise from IVIgs. A decision-analytic model simulated treatment costs attributed to one infusion. Resource use data were derived from a Dutch costing study. Cost items included immunoglobulin costs, pharmacy administration and nursing costs, mini-forfait for hospital infusion, costs of adverse events, and lost productivity with 2009 as base year. Cost data were identified from published sources and Belgian hospital administrators. A probabilistic sensitivity analysis explored the impact of parameter uncertainty on cost results. Costs per infusion cycle in adult primary immunodeficiency patients were €1,046 (95% confidence interval: €1,006-1,093) with Kiovig; €1,102 (€1,064-1,147) with Multigam; and €1,147 (€1,108-1,193) with Sandoglobulin. The average cost savings per infusion with Kiovig as compared to Multigam and Sandoglobulin amounted to €56 and €101 per infusion. In conclusion, treatment costs with Kiovig were shown to be lower as compared to other IVIgs in Belgium. Reduced costs per infusion were attributed to lower costs associated with treating adverse events and the opportunity cost of nursing time and time off work for working adults. Copyright © 2011 Elsevier B.V. All rights reserved.

Cost-effectiveness of long-term outpatient buprenorphine-naloxone treatment for opioid dependence in primary care.

PubMed

Schackman, Bruce R; Leff, Jared A; Polsky, Daniel; Moore, Brent A; Fiellin, David A

2012-06-01

Primary care physicians with appropriate training may prescribe buprenorphine-naloxone (bup/nx) to treat opioid dependence in US office-based settings, where many patients prefer to be treated. Bup/nx is off patent but not available as a generic. We evaluated the cost-effectiveness of long-term office-based bup/nx treatment for clinically stable opioid-dependent patients compared to no treatment. A decision analytic model simulated a hypothetical cohort of clinically stable opioid-dependent individuals who have already completed 6 months of office-based bup/nx treatment. Data were from a published cohort study that collected treatment retention, opioid use, and costs for this population, and published quality-of-life weights. Uncertainties in estimated monthly costs and quality-of-life weights were evaluated in probabilistic sensitivity analyses, and the economic value of additional research to reduce these uncertainties was also evaluated. Bup/nx, provider, and patient costs in 2010 US dollars, quality-adjusted life years (QALYs), and incremental cost-effectiveness (CE) ratios ($/QALY); costs and QALYs are discounted at 3% annually. In the base case, office-based bup/nx for clinically stable patients has a CE ratio of $35,100/QALY compared to no treatment after 24 months, with 64% probability of being < $100,000/QALY in probabilistic sensitivity analysis. With a 50% bup/nx price reduction the CE ratio is $23,000/QALY with 69% probability of being < $100,000/QALY. Alternative quality-of-life weights result in CE ratios of $138,000/QALY and $90,600/QALY. The value of research to reduce quality-of-life uncertainties for 24-month results is $6,400 per person eligible for treatment at the current bup/nx price and $5,100 per person with a 50% bup/nx price reduction. Office-based bup/nx for clinically stable patients may be a cost-effective alternative to no treatment at a threshold of $100,000/QALY depending on assumptions about quality-of-life weights. Additional research about quality-of-life benefits and broader health system and societal cost savings of bup/nx therapy is needed.

Economic and Public Health Impacts of Policies Restricting Access to Hepatitis C Treatment for Medicaid Patients.

PubMed

Chidi, Alexis P; Bryce, Cindy L; Donohue, Julie M; Fine, Michael J; Landsittel, Douglas P; Myaskovsky, Larissa; Rogal, Shari S; Switzer, Galen E; Tsung, Allan; Smith, Kenneth J

2016-06-01

Interferon-free hepatitis C treatment regimens are effective but very costly. The cost-effectiveness, budget, and public health impacts of current Medicaid treatment policies restricting treatment to patients with advanced disease remain unknown. To evaluate the cost-effectiveness of current Medicaid policies restricting hepatitis C treatment to patients with advanced disease compared with a strategy providing unrestricted access to hepatitis C treatment, assess the budget and public health impact of each strategy, and estimate the feasibility and long-term effects of increased access to treatment for patients with hepatitis C. Using a Markov model, we compared two strategies for 45- to 55-year-old Medicaid beneficiaries: 1) Current Practice-only advanced disease is treated before Medicare eligibility and 2) Full Access-both early-stage and advanced disease are treated before Medicare eligibility. Patients could develop progressive fibrosis, cirrhosis, or hepatocellular carcinoma, undergo transplantation, or die each year. Morbidity was reduced after successful treatment. We calculated the incremental cost-effectiveness ratio and compared the costs and public health effects of each strategy from the perspective of Medicare alone as well as the Centers for Medicare & Medicaid Services perspective. We varied model inputs in one-way and probabilistic sensitivity analyses. Full Access was less costly and more effective than Current Practice for all cohorts and perspectives, with differences in cost ranging from $5,369 to $11,960 and in effectiveness from 0.82 to 3.01 quality-adjusted life-years. In a probabilistic sensitivity analysis, Full Access was cost saving in 93% of model iterations. Compared with Current Practice, Full Access averted 5,994 hepatocellular carcinoma cases and 121 liver transplants per 100,000 patients. Current Medicaid policies restricting hepatitis C treatment to patients with advanced disease are more costly and less effective than unrestricted, full-access strategies. Collaboration between state and federal payers may be needed to realize the full public health impact of recent innovations in hepatitis C treatment. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 3: Literature surveys and technical reports

NASA Technical Reports Server (NTRS)

1992-01-01

The technical effort and computer code developed during the first year are summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis.

Cost-effectiveness of staff and workload profiles in retaining patients on antiretroviral therapy in KwaZulu-Natal, South Africa.

PubMed

Vella, Venanzio; Govender, Thiloshini; Dlamini, Sicelo S; Moodley, Indres; David, Verona; Taylor, Myra; Jinabhai, Champaklal C

2011-09-01

There is paucity of information on the cost-effectiveness of delivery strategies to retain patients on antiretroviral therapy (ART) and this study tries to fill this gap. The analysis is based on a representative sample of 2835 patients attending 32 ART sites in KwaZulu-Natal (KZN), South Africa. Extended Cox regression and Kaplan Meier were used to estimate the transition probabilities to remain on ART among patients who attended sites with different staff and workload profiles. Annual costs per patient-year of observation for these delivery profiles were estimated. Probabilistic sensitivity analysis took into account parameters' uncertainty. The delivery sites with a full-time doctor and a full-time senior professional nurse and an intake of less than 200 new patients per doctor per year were the most cost-effective in retaining patients on ART. If 1000 new patients were followed up by this type of site, 724 patients would still be on ART after 10 years at a discounted cost of US$8.41 million at 2006 value with an incremental cost-effectiveness ratio of US$12,271 per extra retained patient over the second not dominated site profile. The results could be used to estimate the human resources needed for a sustainable scaling up of ART in KZN.

Cost-effectiveness of breast cancer screening using mammography in Vietnamese women

PubMed Central

2018-01-01

Background The incidence rate of breast cancer is increasing and has become the most common cancer in Vietnamese women while the survival rate is lower than that of developed countries. Early detection to improve breast cancer survival as well as reducing risk factors remains the cornerstone of breast cancer control according to the World Health Organization (WHO). This study aims to evaluate the costs and outcomes of introducing a mammography screening program for Vietnamese women aged 45–64 years, compared to the current situation of no screening. Methods Decision analytical modeling using Markov chain analysis was used to estimate costs and health outcomes over a lifetime horizon. Model inputs were derived from published literature and the results were reported as incremental cost-effectiveness ratios (ICERs) and/or incremental net monetary benefits (INMBs). One-way sensitivity analyses and probabilistic sensitivity analyses were performed to assess parameter uncertainty. Results The ICER per life year gained of the first round of mammography screening was US$3647.06 and US$4405.44 for women aged 50–54 years and 55–59 years, respectively. In probabilistic sensitivity analyses, mammography screening in the 50–54 age group and the 55–59 age group were cost-effective in 100% of cases at a threshold of three times the Vietnamese Gross Domestic Product (GDP) i.e., US$6332.70. However, less than 50% of the cases in the 60–64 age group and 0% of the cases in the 45–49 age group were cost effective at the WHO threshold. The ICERs were sensitive to the discount rate, mammography sensitivity, and transition probability from remission to distant recurrence in stage II for all age groups. Conclusion From the healthcare payer viewpoint, offering the first round of mammography screening to Vietnamese women aged 50–59 years should be considered, with the given threshold of three times the Vietnamese GDP per capita. PMID:29579131

A cost per live birth comparison of HMG and rFSH randomized trials.

PubMed

Connolly, Mark; De Vrieze, Kathleen; Ombelet, Willem; Schneider, Dirk; Currie, Craig

2008-12-01

To help inform healthcare treatment practices and funding decisions, an economic evaluation was conducted to compare the two leading gonadotrophins used for IVF in Belgium. Based on the results of a recently published meta-analysis, a simulated decision tree model was constructed with four states: (i) fresh cycle, (ii) cryopreserved cycle, (iii) live birth and (iv) treatment withdrawal. Gonadotrophin costs were based on highly purified human menopausal gonadotrophin (HP-HMG; Menopur) and recombinant FSH (rFSH) alpha (Gonal-F). After one fresh and one cryopreserved cycle the average treatment cost with HP-HMG was lower than with rFSH (HP-HMG euro3635; rFSH euro4103). The average cost saving per person started on HP-HMG when compared with rFSH was euro468. Additionally, the average costs per live birth of HP-HMG and rFSH were found to be significantly different: HP-HMG euro9996; rFSH euro13,009 (P < 0.0001). HP-HMG remained cost-saving even after key parameters in the model were varied in the probabilistic sensitivity analysis. Treatment with HP-HMG was found to be the dominant treatment strategy in IVF because of improved live birth rates and lower costs. Within a fixed healthcare budget, the cost-savings achieved using HP-HMG would allow for the delivery of additional IVF cycles.

A comparison of economic evaluation models as applied to geothermal energy technology

NASA Technical Reports Server (NTRS)

Ziman, G. M.; Rosenberg, L. S.

1983-01-01

Several cost estimation and financial cash flow models have been applied to a series of geothermal case studies. In order to draw conclusions about relative performance and applicability of these models to geothermal projects, the consistency of results was assessed. The model outputs of principal interest in this study were net present value, internal rate of return, or levelized breakeven price. The models used were VENVAL, a venture analysis model; the Geothermal Probabilistic Cost Model (GPC Model); the Alternative Power Systems Economic Analysis Model (APSEAM); the Geothermal Loan Guarantee Cash Flow Model (GCFM); and the GEOCOST and GEOCITY geothermal models. The case studies to which the models were applied include a geothermal reservoir at Heber, CA; a geothermal eletric power plant to be located at the Heber site; an alcohol fuels production facility to be built at Raft River, ID; and a direct-use, district heating system in Susanville, CA.

A cost-effectiveness analysis of combination antiplatelet therapy for high-risk acute coronary syndromes: clopidogrel plus aspirin versus aspirin alone.

PubMed

Schleinitz, Mark D; Heidenreich, Paul A

2005-02-15

Although clopidogrel plus aspirin is more effective than aspirin alone in preventing subsequent vascular events in patients with unstable angina, the cost-effectiveness of this combination has yet to be examined in this high-risk population. To determine the cost-effectiveness of clopidogrel plus aspirin compared with aspirin alone. Cost-utility analysis. Published literature. Patients with unstable angina and electrocardiographic changes or non-Q-wave myocardial infarction. time horizon: Lifetime. Societal. Combination therapy with clopidogrel, 75 mg/d, plus aspirin, 325 mg/d, for 1 year, followed by aspirin monotherapy, was compared with lifelong aspirin therapy, 325 mg/d. Lifetime costs, life expectancy in quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio. Patients treated with aspirin alone lived 9.51 QALYs after their initial event and incurred expenses of 127,700 dollars; the addition of clopidogrel increased life expectancy to 9.61 QALYs and costs to 129,300 dollars. The incremental cost-effectiveness ratio for clopidogrel plus aspirin compared with aspirin alone was 15,400 dollars per QALY. The analysis of 1 year of therapy was robust to all sensitivity analyses. In the probabilistic sensitivity analysis, fewer than 3% of simulations resulted in cost-effectiveness ratios over 50,000 dollars per QALY. The cost-effectiveness of longer combination therapy depends critically on the balance of thrombotic event rates, durable efficacy, and the increased bleeding rate in patients taking clopidogrel. This analysis may not apply to patients with severe heart failure, those undergoing long-term anticoagulant therapy, those recently managed with revascularization, or those undergoing short-term treatment with glycoprotein IIb/IIIa inhibitors. In patients with high-risk acute coronary syndromes, 1 year of therapy with clopidogrel plus aspirin results in greater life expectancy than aspirin alone, at a cost within the traditional limits of cost-effectiveness. The durable efficacy of clopidogrel relative to the risk for hemorrhage should be further explored before more protracted therapy can be recommended.

Use of Probabilistic Engineering Methods in the Detailed Design and Development Phases of the NASA Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Fayssal, Safie; Weldon, Danny

2008-01-01

The United States National Aeronautics and Space Administration (NASA) is in the midst of a space exploration program called Constellation to send crew and cargo to the international Space Station, to the moon, and beyond. As part of the Constellation program, a new launch vehicle, Ares I, is being developed by NASA Marshall Space Flight Center. Designing a launch vehicle with high reliability and increased safety requires a significant effort in understanding design variability and design uncertainty at the various levels of the design (system, element, subsystem, component, etc.) and throughout the various design phases (conceptual, preliminary design, etc.). In a previous paper [1] we discussed a probabilistic functional failure analysis approach intended mainly to support system requirements definition, system design, and element design during the early design phases. This paper provides an overview of the application of probabilistic engineering methods to support the detailed subsystem/component design and development as part of the "Design for Reliability and Safety" approach for the new Ares I Launch Vehicle. Specifically, the paper discusses probabilistic engineering design analysis cases that had major impact on the design and manufacturing of the Space Shuttle hardware. The cases represent important lessons learned from the Space Shuttle Program and clearly demonstrate the significance of probabilistic engineering analysis in better understanding design deficiencies and identifying potential design improvement for Ares I. The paper also discusses the probabilistic functional failure analysis approach applied during the early design phases of Ares I and the forward plans for probabilistic design analysis in the detailed design and development phases.

Cost-utility analysis of 10- and 13-valent pneumococcal conjugate vaccines: Protection at what price in the Thai context?

PubMed Central

Kulpeng, Wantanee; Leelahavarong, Pattara; Rattanavipapong, Waranya; Sornsrivichai, Vorasith; Baggett, Henry C.; Meeyai, Aronrag; Punpanich, Warunee; Teerawattananon, Yot

2015-01-01

Objective This study aims to evaluate the costs and outcomes of offering the 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13) in Thailand compared to the current situation of no PCV vaccination. Methods Two vaccination schedules were considered: two-dose primary series plus a booster dose (2 + 1) and three-dose primary series plus a booster dose (3 + 1). A cost-utility analysis was conducted using a societal perspective. A Markov simulation model was used to estimate the relevant costs and health outcomes for a lifetime horizon. Costs were collected and values were calculated for the year 2010. The results were reported as incremental cost-effectiveness ratios (ICERs) in Thai Baht (THB) per quality adjusted life year (QALY) gained, with future costs and outcomes being discounted at 3% per annum. One-way sensitivity analysis and probabilistic sensitivity analysis using a Monte Carlo simulation were performed to assess parameter uncertainty. Results Under the base case-scenario of 2 + 1 dose schedule and a five-year protection, without indirect vaccine effects, the ICER for PCV10 and PCV13 were THB 1,368,072 and THB 1,490,305 per QALY gained, respectively. With indirect vaccine effects, the ICER of PCV10 was THB 519,399, and for PCV13 was THB 527,378. The model was sensitive to discount rate, the change in duration of vaccine protection and the incidence of pneumonia for all age groups. Conclusions At current prices, PCV10 and PCV13 are not cost-effective in Thailand. Inclusion of indirect vaccine effects substantially reduced the ICERs for both vaccines, but did not result in cost effectiveness. PMID:23588084

Bayesian wavelet PCA methodology for turbomachinery damage diagnosis under uncertainty

NASA Astrophysics Data System (ADS)

Xu, Shengli; Jiang, Xiaomo; Huang, Jinzhi; Yang, Shuhua; Wang, Xiaofang

2016-12-01

Centrifugal compressor often suffers various defects such as impeller cracking, resulting in forced outage of the total plant. Damage diagnostics and condition monitoring of such a turbomachinery system has become an increasingly important and powerful tool to prevent potential failure in components and reduce unplanned forced outage and further maintenance costs, while improving reliability, availability and maintainability of a turbomachinery system. This paper presents a probabilistic signal processing methodology for damage diagnostics using multiple time history data collected from different locations of a turbomachine, considering data uncertainty and multivariate correlation. The proposed methodology is based on the integration of three advanced state-of-the-art data mining techniques: discrete wavelet packet transform, Bayesian hypothesis testing, and probabilistic principal component analysis. The multiresolution wavelet analysis approach is employed to decompose a time series signal into different levels of wavelet coefficients. These coefficients represent multiple time-frequency resolutions of a signal. Bayesian hypothesis testing is then applied to each level of wavelet coefficient to remove possible imperfections. The ratio of posterior odds Bayesian approach provides a direct means to assess whether there is imperfection in the decomposed coefficients, thus avoiding over-denoising. Power spectral density estimated by the Welch method is utilized to evaluate the effectiveness of Bayesian wavelet cleansing method. Furthermore, the probabilistic principal component analysis approach is developed to reduce dimensionality of multiple time series and to address multivariate correlation and data uncertainty for damage diagnostics. The proposed methodology and generalized framework is demonstrated with a set of sensor data collected from a real-world centrifugal compressor with impeller cracks, through both time series and contour analyses of vibration signal and principal components.

Cost Utility Analysis of Topical Steroids Compared With Dietary Elimination for Treatment of Eosinophilic Esophagitis.

PubMed

Cotton, Cary C; Erim, Daniel; Eluri, Swathi; Palmer, Sarah H; Green, Daniel J; Wolf, W Asher; Runge, Thomas M; Wheeler, Stephanie; Shaheen, Nicholas J; Dellon, Evan S

2017-06-01

Topical corticosteroids or dietary elimination are recommended as first-line therapies for eosinophilic esophagitis, but data to directly compare these therapies are scant. We performed a cost utility comparison of topical corticosteroids and the 6-food elimination diet (SFED) in treatment of eosinophilic esophagitis, from the payer perspective. We used a modified Markov model based on current clinical guidelines, in which transition between states depended on histologic response simulated at the individual cohort-member level. Simulation parameters were defined by systematic review and meta-analysis to determine the base-case estimates and bounds of uncertainty for sensitivity analysis. Meta-regression models included adjustment for differences in study and cohort characteristics. In the base-case scenario, topical fluticasone was about as effective as SFED but more expensive at a 5-year time horizon ($9261.58 vs $5719.72 per person). SFED was more effective and less expensive than topical fluticasone and topical budesonide in the base-case scenario. Probabilistic sensitivity analysis revealed little uncertainty in relative treatment effectiveness. There was somewhat greater uncertainty in the relative cost of treatments; most simulations found SFED to be less expensive. In a cost utility analysis comparing topical corticosteroids and SFED for first-line treatment of eosinophilic esophagitis, the therapies were similar in effectiveness. SFED was on average less expensive, and more cost effective in most simulations, than topical budesonide and topical fluticasone, from a payer perspective and not accounting for patient-level costs or quality of life. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Probabilistic Sensitivity Analysis of Fretting Fatigue (Preprint)

DTIC Science & Technology

2009-04-01

AFRL-RX-WP-TP-2009-4091 PROBABILISTIC SENSITIVITY ANALYSIS OF FRETTING FATIGUE (Preprint) Patrick J. Golden, Harry R. Millwater , and...Sensitivity Analysis of Fretting Fatigue Patrick J. Golden * Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 Harry R. Millwater † and

Probabilistic simulation of stress concentration in composite laminates

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Murthy, P. L. N.; Liaw, L.

1993-01-01

A computational methodology is described to probabilistically simulate the stress concentration factors in composite laminates. This new approach consists of coupling probabilistic composite mechanics with probabilistic finite element structural analysis. The probabilistic composite mechanics is used to probabilistically describe all the uncertainties inherent in composite material properties while probabilistic finite element is used to probabilistically describe the uncertainties associated with methods to experimentally evaluate stress concentration factors such as loads, geometry, and supports. The effectiveness of the methodology is demonstrated by using it to simulate the stress concentration factors in composite laminates made from three different composite systems. Simulated results match experimental data for probability density and for cumulative distribution functions. The sensitivity factors indicate that the stress concentration factors are influenced by local stiffness variables, by load eccentricities and by initial stress fields.

Probabilistic load simulation: Code development status

NASA Astrophysics Data System (ADS)

Newell, J. F.; Ho, H.

1991-05-01

The objective of the Composite Load Spectra (CLS) project is to develop generic load models to simulate the composite load spectra that are included in space propulsion system components. The probabilistic loads thus generated are part of the probabilistic design analysis (PDA) of a space propulsion system that also includes probabilistic structural analyses, reliability, and risk evaluations. Probabilistic load simulation for space propulsion systems demands sophisticated probabilistic methodology and requires large amounts of load information and engineering data. The CLS approach is to implement a knowledge based system coupled with a probabilistic load simulation module. The knowledge base manages and furnishes load information and expertise and sets up the simulation runs. The load simulation module performs the numerical computation to generate the probabilistic loads with load information supplied from the CLS knowledge base.

Probabilistic boundary element method

NASA Technical Reports Server (NTRS)

Cruse, T. A.; Raveendra, S. T.

1989-01-01

The purpose of the Probabilistic Structural Analysis Method (PSAM) project is to develop structural analysis capabilities for the design analysis of advanced space propulsion system hardware. The boundary element method (BEM) is used as the basis of the Probabilistic Advanced Analysis Methods (PADAM) which is discussed. The probabilistic BEM code (PBEM) is used to obtain the structural response and sensitivity results to a set of random variables. As such, PBEM performs analogous to other structural analysis codes such as finite elements in the PSAM system. For linear problems, unlike the finite element method (FEM), the BEM governing equations are written at the boundary of the body only, thus, the method eliminates the need to model the volume of the body. However, for general body force problems, a direct condensation of the governing equations to the boundary of the body is not possible and therefore volume modeling is generally required.

Cost-Effectiveness Analysis of the Self-Management Program for Thai Patients with Metabolic Syndrome.

PubMed

Sakulsupsiri, Anut; Sakthong, Phantipa; Winit-Watjana, Win

2016-05-01

Lifestyle modification programs are partly evaluated for their usefulness. This study aimed to assess the cost-effectiveness and healthy lifestyle persistence of a self-management program (SMP) for patients with metabolic syndrome (MetS) in Thai health care settings. A cost-effectiveness analysis was performed on the basis of an intervention study of 90 patients with MetS randomly allocated to the SMP and control groups. A Markov model with the Difference-in-Difference method was used to predict the lifetime costs from a societal perspective and quality-adjusted life-years (QALYs), of which 95% confidence intervals (CIs) were estimated by bootstrapping. The cost-effectiveness analysis, along with healthy lifestyle persistence, was performed using the discount rate of 3% per annum. Parameter uncertainties were identified using one-way and probabilistic sensitivity analyses. The lifetime costs tended to decrease in both groups. The SMP could save lifetime costs (-2310 baht; 95% CI -5960 to 1400) and gain QALYs (0.0098; 95% CI -0.0003 to 0.0190), compared with ordinary care. The probability of cost-effectiveness was 99.4% from the Monte-Carlo simulation, and the program was deemed cost-effective at dropout rates below 69% per year as determined by the threshold of 160,000 baht per QALY gained. The cost of macrovascular complications was the most influencing variable for the overall incremental cost-effectiveness ratio. The SMP provided by the health care settings is marginally cost-effective, and the persistence results support the implementation of the program to minimize the complications and economic burden of patients with MetS. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Total thyroidectomy versus hemithyroidectomy for patients with follicular neoplasm. A cost-utility analysis.

PubMed

Corso, C; Gomez, X; Sanabria, A; Vega, V; Dominguez, L C; Osorio, C

2014-01-01

Thyroid nodules are a common condition. Overall, 20% of the nodules assessed with FNAB correspond to the follicular pattern. A partial thyroidectomy is the minimal procedure that should be performed to determine the nature of these nodules. Some authors have suggested performing a total thyroidectomy based on the elimination of reoperation and ultrasound follow-up. The aim of this study was to evaluate the most cost-useful surgical strategy in a patient with an undetermined nodule, assessing complications, reoperation, recurrence and costs. A cost-utility study was designed to compare hemithyroidectomy and total thyroidectomy. The outcomes were complications (definitive RLN palsy, permanent hypoparathyroidism, reoperation for cancer, and recurrence of the disease), direct costs and utility. We used the payer perspective at 5 years. A deterministic and probabilistic sensitivity analysis was completed. In a deterministic analysis, the cost, utility and cost-utility ratio was COP $12.981.801, 44.5 and COP $291.310 for total thyroidectomy and COP $14.309.889, 42.0 and $340.044 for partial thyroidectomy, respectively. The incremental cost-utility ratio was -$535.302 favoring total thyroidectomy. Partial thyroidectomy was more cost-effective when the risks of RLN injury and definitive hypoparathyroidism were greater than 8% and 9% in total thyroidectomy, respectively. In total, 46.8% of the simulations for partial thyroidectomy were located in the quadrant of more costly and less effective. Under a common range of complications, and considering the patient's preference and costs, total thyroidectomy should be selected as the most cost-effective treatment for patients with thyroid nodules and follicular patterns. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Placental alpha-microglobulin-1 and combined traditional diagnostic test: a cost-benefit analysis.

PubMed

Echebiri, Nelson C; McDoom, M Maya; Pullen, Jessica A; Aalto, Meaghan M; Patel, Natasha N; Doyle, Nora M

2015-01-01

We sought to evaluate if the placental alpha-microglobulin (PAMG)-1 test vs the combined traditional diagnostic test (CTDT) of pooling, nitrazine, and ferning would be a cost-beneficial screening strategy in the setting of potential preterm premature rupture of membranes. A decision analysis model was used to estimate the economic impact of PAMG-1 test vs the CTDT on preterm delivery costs from a societal perspective. Our primary outcome was the annual net cost-benefit per person tested. Baseline probabilities and costs assumptions were derived from published literature. We conducted sensitivity analyses using both deterministic and probabilistic models. Cost estimates reflect 2013 US dollars. Annual net benefit from PAMG-1 was $20,014 per person tested, while CTDT had a net benefit of $15,757 per person tested. If the probability of rupture is <38%, PAMG-1 will be cost-beneficial with an annual net benefit of $16,000-37,000 per person tested, while CTDT will have an annual net benefit of $16,000-19,500 per person tested. If the probability of rupture is >38%, CTDT is more cost-beneficial. Monte Carlo simulations of 1 million trials selected PAMG-1 as the optimal strategy with a frequency of 89%, while CTDT was only selected as the optimal strategy with a frequency of 11%. Sensitivity analyses were robust. Our cost-benefit analysis provides the economic evidence for the adoption of PAMG-1 in diagnosing preterm premature rupture of membranes in uncertain presentations and when CTDT is equivocal at 34 to <37 weeks' gestation. Copyright © 2015 Elsevier Inc. All rights reserved.

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 5: Auxiliary shuttle risk analyses

NASA Technical Reports Server (NTRS)

Fragola, Joseph R.; Maggio, Gaspare; Frank, Michael V.; Gerez, Luis; Mcfadden, Richard H.; Collins, Erin P.; Ballesio, Jorge; Appignani, Peter L.; Karns, James J.

1995-01-01

Volume 5 is Appendix C, Auxiliary Shuttle Risk Analyses, and contains the following reports: Probabilistic Risk Assessment of Space Shuttle Phase 1 - Space Shuttle Catastrophic Failure Frequency Final Report; Risk Analysis Applied to the Space Shuttle Main Engine - Demonstration Project for the Main Combustion Chamber Risk Assessment; An Investigation of the Risk Implications of Space Shuttle Solid Rocket Booster Chamber Pressure Excursions; Safety of the Thermal Protection System of the Space Shuttle Orbiter - Quantitative Analysis and Organizational Factors; Space Shuttle Main Propulsion Pressurization System Probabilistic Risk Assessment, Final Report; and Space Shuttle Probabilistic Risk Assessment Proof-of-Concept Study - Auxiliary Power Unit and Hydraulic Power Unit Analysis Report.

The Cost-Effectiveness of Surgical Treatment of Medial Unicompartmental Knee Osteoarthritis in Younger Patients

PubMed Central

Konopka, Joseph F.; Gomoll, Andreas H.; Thornhill, Thomas S.; Katz, Jeffrey N.; Losina, Elena

2015-01-01

Background: Surgical options for the management of medial compartment osteoarthritis of the varus knee include high tibial osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty. We sought to determine the cost-effectiveness of high tibial osteotomy and unicompartmental knee arthroplasty as alternatives to total knee arthroplasty for patients fifty to sixty years of age. Methods: We built a probabilistic state-transition computer model with health states defined by pain, postoperative complications, and subsequent surgical procedures. We estimated transition probabilities from published literature. Costs were determined from Medicare reimbursement schedules. Health outcomes were measured in quality-adjusted life-years (QALYs). We conducted analyses over patients’ lifetimes from the societal perspective, with health and cost outcomes discounted by 3% annually. We used probabilistic sensitivity analyses to account for uncertainty in data inputs. Results: The estimated discounted QALYs were 14.62, 14.63, and 14.64 for high tibial osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty, respectively. Discounted total direct medical costs were $20,436 for high tibial osteotomy, $24,637 for unicompartmental knee arthroplasty, and $24,761 for total knee arthroplasty (in 2012 U.S. dollars). The incremental cost-effectiveness ratio (ICER) was $231,900 per QALY for total knee arthroplasty and $420,100 per QALY for unicompartmental knee arthroplasty. Probabilistic sensitivity analyses showed that, at a willingness-to-pay (WTP) threshold of $50,000 per QALY, high tibial osteotomy was cost-effective 57% of the time; total knee arthroplasty, 24%; and unicompartmental knee arthroplasty, 19%. At a WTP threshold of $100,000 per QALY, high tibial osteotomy was cost-effective 43% of time; total knee arthroplasty, 31%; and unicompartmental knee arthroplasty, 26%. Conclusions: In fifty to sixty-year-old patients with medial unicompartmental knee osteoarthritis, high tibial osteotomy is an attractive option compared with unicompartmental knee arthroplasty and total knee arthroplasty. This finding supports greater utilization of high tibial osteotomy for these patients. The cost-effectiveness of high tibial osteotomy and of unicompartmental knee arthroplasty depend on rates of conversion to total knee arthroplasty and the clinical outcomes of the conversions. Level of Evidence: Economic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:25995491

When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

PubMed

Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

2015-11-01

Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news. © Society for the Experimental Analysis of Behavior.

Probabilistic volcanic hazard assessments of Pyroclastic Density Currents: ongoing practices and future perspectives

NASA Astrophysics Data System (ADS)

Tierz, Pablo; Sandri, Laura; Ramona Stefanescu, Elena; Patra, Abani; Marzocchi, Warner; Costa, Antonio; Sulpizio, Roberto

2014-05-01

Explosive volcanoes and, especially, Pyroclastic Density Currents (PDCs) pose an enormous threat to populations living in the surroundings of volcanic areas. Difficulties in the modeling of PDCs are related to (i) very complex and stochastic physical processes, intrinsic to their occurrence, and (ii) to a lack of knowledge about how these processes actually form and evolve. This means that there are deep uncertainties (namely, of aleatory nature due to point (i) above, and of epistemic nature due to point (ii) above) associated to the study and forecast of PDCs. Consequently, the assessment of their hazard is better described in terms of probabilistic approaches rather than by deterministic ones. What is actually done to assess probabilistic hazard from PDCs is to couple deterministic simulators with statistical techniques that can, eventually, supply probabilities and inform about the uncertainties involved. In this work, some examples of both PDC numerical simulators (Energy Cone and TITAN2D) and uncertainty quantification techniques (Monte Carlo sampling -MC-, Polynomial Chaos Quadrature -PCQ- and Bayesian Linear Emulation -BLE-) are presented, and their advantages, limitations and future potential are underlined. The key point in choosing a specific method leans on the balance between its related computational cost, the physical reliability of the simulator and the pursued target of the hazard analysis (type of PDCs considered, time-scale selected for the analysis, particular guidelines received from decision-making agencies, etc.). Although current numerical and statistical techniques have brought important advances in probabilistic volcanic hazard assessment from PDCs, some of them may be further applicable to more sophisticated simulators. In addition, forthcoming improvements could be focused on three main multidisciplinary directions: 1) Validate the simulators frequently used (through comparison with PDC deposits and other simulators), 2) Decrease simulator runtimes (whether by increasing the knowledge about the physical processes or by doing more efficient programming, parallelization, ...) and 3) Improve uncertainty quantification techniques.

Toward a Responsibility-Catering Prioritarian Ethical Theory of Risk.

PubMed

Wikman-Svahn, Per; Lindblom, Lars

2018-03-05

Standard tools used in societal risk management such as probabilistic risk analysis or cost-benefit analysis typically define risks in terms of only probabilities and consequences and assume a utilitarian approach to ethics that aims to maximize expected utility. The philosopher Carl F. Cranor has argued against this view by devising a list of plausible aspects of the acceptability of risks that points towards a non-consequentialist ethical theory of societal risk management. This paper revisits Cranor's list to argue that the alternative ethical theory responsibility-catering prioritarianism can accommodate the aspects identified by Cranor and that the elements in the list can be used to inform the details of how to view risks within this theory. An approach towards operationalizing the theory is proposed based on a prioritarian social welfare function that operates on responsibility-adjusted utilities. A responsibility-catering prioritarian ethical approach towards managing risks is a promising alternative to standard tools such as cost-benefit analysis.

Cost-Effectiveness Analysis of Acupuncture, Counselling and Usual Care in Treating Patients with Depression: The Results of the ACUDep Trial

PubMed Central

Spackman, Eldon; Richmond, Stewart; Sculpher, Mark; Bland, Martin; Brealey, Stephen; Gabe, Rhian; Hopton, Ann; Keding, Ada; Lansdown, Harriet; Perren, Sara; Torgerson, David; Watt, Ian; MacPherson, Hugh

2014-01-01

Background New evidence on the clinical effectiveness of acupuncture plus usual care (acupuncture) and counselling plus usual care (counselling) for patients with depression suggests the need to investigate the health-related quality of life and costs of these treatments to understand whether they should be considered a good use of limited health resources. Methods and Findings The cost-effectiveness analyses are based on the Acupuncture, Counselling or Usual care for Depression (ACUDep) trial results. Statistical analyses demonstrate a difference in mean quality adjusted life years (QALYs) and suggest differences in mean costs which are mainly due to the price of the interventions. Probabilistic sensitivity analysis is used to express decision uncertainty. Acupuncture and counselling are found to have higher mean QALYs and costs than usual care. In the base case analysis acupuncture has an incremental cost-effectiveness ratio (ICER) of £4,560 per additional QALY and is cost-effective with a probability of 0.62 at a cost-effectiveness threshold of £20,000 per QALY. Counselling compared with acupuncture is more effective and more costly with an ICER of £71,757 and a probability of being cost-effective of 0.36. A scenario analysis of counselling versus usual care, excluding acupuncture as a comparator, results in an ICER of £7,935 and a probability of 0.91. Conclusions Acupuncture is cost-effective compared with counselling or usual care alone, although the ranking of counselling and acupuncture depends on the relative cost of delivering these interventions. For patients in whom acupuncture is unavailable or perhaps inappropriate, counselling has an ICER less than most cost-effectiveness thresholds. However, further research is needed to determine the most cost-effective treatment pathways for depressed patients when the full range of available interventions is considered. PMID:25426637

Does directly administered antiretroviral therapy represent good value for money in sub-Saharan Africa? A cost-utility and value of information analysis.

PubMed

Uthman, Rashidah T; Sutton, Andrew J; Jackson, Louise J; Uthman, Olalekan A

2018-01-01

Successful antiretroviral therapy (ART) relies on the optimal level of ART adherence to achieve reliable viral suppression, avert HIV drug resistance, and prevent avoidable deaths. It has been shown that there are various groups of people living with HIV at high-risk of non-adherence to ART in sub-Saharan Africa. The objective of this study was to examine the cost effectiveness and value-of-information of directly administered antiretroviral therapy (DAART) versus self-administered ART among people living with HIV, at high risk of non-adherence to ART in sub-Saharan Africa. A Markov model was developed that describes the transition between HIV stages based on the CD4 count, along with direct costs, quality of life and the mortality rate associated with DAART in comparison with self-administered ART. Data used in the model were derived from the published literature. A health system perspective was employed using a life-time time horizon. Probabilistic sensitivity analysis was performed to determine the impact of parameter uncertainty. Value of information analysis was also conducted. The expected cost of self-administered ART and DAART were $5,200 and $15,500 and the expected QALYs gained were 8.52 and 9.75 respectively, giving an incremental cost effectiveness ratio of $8,400 per QALY gained. The analysis demonstrated that the annual cost DAART needs to be priced below $200 per patient to be cost-effective. The probability that DAART was cost-effective was 1% for a willingness to pay threshold of $5,096 for sub-Saharan Africa. The value of information associated with the cost of DAART and its effectiveness was substantial. From the perspective of the health care payer in sub-Saharan Africa, DAART cannot be regarded as cost-effective based on current information. The value of information analysis showed that further research will be worthwhile and potentially cost-effective in resolving the uncertainty about whether or not to adopt DAART.

Recommendations for Methicillin-Resistant Staphylococcus aureus Prevention in Adult ICUs: A Cost-Effectiveness Analysis.

PubMed

Whittington, Melanie D; Atherly, Adam J; Curtis, Donna J; Lindrooth, Richard C; Bradley, Cathy J; Campbell, Jonathan D

2017-08-01

Patients in the ICU are at the greatest risk of contracting healthcare-associated infections like methicillin-resistant Staphylococcus aureus. This study calculates the cost-effectiveness of methicillin-resistant S aureus prevention strategies and recommends specific strategies based on screening test implementation. A cost-effectiveness analysis using a Markov model from the hospital perspective was conducted to determine if the implementation costs of methicillin-resistant S aureus prevention strategies are justified by associated reductions in methicillin-resistant S aureus infections and improvements in quality-adjusted life years. Univariate and probabilistic sensitivity analyses determined the influence of input variation on the cost-effectiveness. ICU. Hypothetical cohort of adults admitted to the ICU. Three prevention strategies were evaluated, including universal decolonization, targeted decolonization, and screening and isolation. Because prevention strategies have a screening component, the screening test in the model was varied to reflect commonly used screening test categories, including conventional culture, chromogenic agar, and polymerase chain reaction. Universal and targeted decolonization are less costly and more effective than screening and isolation. This is consistent for all screening tests. When compared with targeted decolonization, universal decolonization is cost-saving to cost-effective, with maximum cost savings occurring when a hospital uses more expensive screening tests like polymerase chain reaction. Results were robust to sensitivity analyses. As compared with screening and isolation, the current standard practice in ICUs, targeted decolonization, and universal decolonization are less costly and more effective. This supports updating the standard practice to a decolonization approach.

Cost-Effectiveness and Value of Information Analysis of Brief Interventions to Promote Physical Activity in Primary Care.

PubMed

Gc, Vijay Singh; Suhrcke, Marc; Hardeman, Wendy; Sutton, Stephen; Wilson, Edward C F

2018-01-01

Brief interventions (BIs) delivered in primary care have shown potential to increase physical activity levels and may be cost-effective, at least in the short-term, when compared with usual care. Nevertheless, there is limited evidence on their longer term costs and health benefits. To estimate the cost-effectiveness of BIs to promote physical activity in primary care and to guide future research priorities using value of information analysis. A decision model was used to compare the cost-effectiveness of three classes of BIs that have been used, or could be used, to promote physical activity in primary care: 1) pedometer interventions, 2) advice/counseling on physical activity, and (3) action planning interventions. Published risk equations and data from the available literature or routine data sources were used to inform model parameters. Uncertainty was investigated with probabilistic sensitivity analysis, and value of information analysis was conducted to estimate the value of undertaking further research. In the base-case, pedometer interventions yielded the highest expected net benefit at a willingness to pay of £20,000 per quality-adjusted life-year. There was, however, a great deal of decision uncertainty: the expected value of perfect information surrounding the decision problem for the National Health Service Health Check population was estimated at £1.85 billion. Our analysis suggests that the use of pedometer BIs is the most cost-effective strategy to promote physical activity in primary care, and that there is potential value in further research into the cost-effectiveness of brief (i.e., <30 minutes) and very brief (i.e., <5 minutes) pedometer interventions in this setting. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Economic Evaluation of First-Line Treatments for Metastatic Renal Cell Carcinoma: A Cost-Effectiveness Analysis in A Health Resource–Limited Setting

PubMed Central

Wu, Bin; Dong, Baijun; Xu, Yuejuan; Zhang, Qiang; Shen, Jinfang; Chen, Huafeng; Xue, Wei

2012-01-01

Background To estimate, from the perspective of the Chinese healthcare system, the economic outcomes of five different first-line strategies among patients with metastatic renal cell carcinoma (mRCC). Methods and Findings A decision-analytic model was developed to simulate the lifetime disease course associated with renal cell carcinoma. The health and economic outcomes of five first-line strategies (interferon-alfa, interleukin-2, interleukin-2 plus interferon-alfa, sunitinib and bevacizumab plus interferon-alfa) were estimated and assessed by indirect comparison. The clinical and utility data were taken from published studies. The cost data were estimated from local charge data and current Chinese practices. Sensitivity analyses were used to explore the impact of uncertainty regarding the results. The impact of the sunitinib patient assistant program (SPAP) was evaluated via scenario analysis. The base-case analysis showed that the sunitinib strategy yielded the maximum health benefits: 2.71 life years and 1.40 quality-adjusted life-years (QALY). The marginal cost-effectiveness (cost per additional QALY) gained via the sunitinib strategy compared with the conventional strategy was $220,384 (without SPAP, interleukin-2 plus interferon-alfa and bevacizumab plus interferon-alfa were dominated) and $16,993 (with SPAP, interferon-alfa, interleukin-2 plus interferon-alfa and bevacizumab plus interferon-alfa were dominated). In general, the results were sensitive to the hazard ratio of progression-free survival. The probabilistic sensitivity analysis demonstrated that the sunitinib strategy with SPAP was the most cost-effective approach when the willingness-to-pay threshold was over $16,000. Conclusions Our analysis suggests that traditional cytokine therapy is the cost-effective option in the Chinese healthcare setting. In some relatively developed regions, sunitinib with SPAP may be a favorable cost-effective alternative for mRCC. PMID:22412884

Economic evaluation of first-line treatments for metastatic renal cell carcinoma: a cost-effectiveness analysis in a health resource-limited setting.

PubMed

Wu, Bin; Dong, Baijun; Xu, Yuejuan; Zhang, Qiang; Shen, Jinfang; Chen, Huafeng; Xue, Wei

2012-01-01

To estimate, from the perspective of the Chinese healthcare system, the economic outcomes of five different first-line strategies among patients with metastatic renal cell carcinoma (mRCC). A decision-analytic model was developed to simulate the lifetime disease course associated with renal cell carcinoma. The health and economic outcomes of five first-line strategies (interferon-alfa, interleukin-2, interleukin-2 plus interferon-alfa, sunitinib and bevacizumab plus interferon-alfa) were estimated and assessed by indirect comparison. The clinical and utility data were taken from published studies. The cost data were estimated from local charge data and current Chinese practices. Sensitivity analyses were used to explore the impact of uncertainty regarding the results. The impact of the sunitinib patient assistant program (SPAP) was evaluated via scenario analysis. The base-case analysis showed that the sunitinib strategy yielded the maximum health benefits: 2.71 life years and 1.40 quality-adjusted life-years (QALY). The marginal cost-effectiveness (cost per additional QALY) gained via the sunitinib strategy compared with the conventional strategy was $220,384 (without SPAP, interleukin-2 plus interferon-alfa and bevacizumab plus interferon-alfa were dominated) and $16,993 (with SPAP, interferon-alfa, interleukin-2 plus interferon-alfa and bevacizumab plus interferon-alfa were dominated). In general, the results were sensitive to the hazard ratio of progression-free survival. The probabilistic sensitivity analysis demonstrated that the sunitinib strategy with SPAP was the most cost-effective approach when the willingness-to-pay threshold was over $16,000. Our analysis suggests that traditional cytokine therapy is the cost-effective option in the Chinese healthcare setting. In some relatively developed regions, sunitinib with SPAP may be a favorable cost-effective alternative for mRCC.

Different Imaging Strategies in Patients With Possible Basilar Artery Occlusion: Cost-Effectiveness Analysis.

PubMed

Beyer, Sebastian E; Hunink, Myriam G; Schöberl, Florian; von Baumgarten, Louisa; Petersen, Steffen E; Dichgans, Martin; Janssen, Hendrik; Ertl-Wagner, Birgit; Reiser, Maximilian F; Sommer, Wieland H

2015-07-01

This study evaluated the cost-effectiveness of different noninvasive imaging strategies in patients with possible basilar artery occlusion. A Markov decision analytic model was used to evaluate long-term outcomes resulting from strategies using computed tomographic angiography (CTA), magnetic resonance imaging, nonenhanced CT, or duplex ultrasound with intravenous (IV) thrombolysis being administered after positive findings. The analysis was performed from the societal perspective based on US recommendations. Input parameters were derived from the literature. Costs were obtained from United States costing sources and published literature. Outcomes were lifetime costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, and net monetary benefits, with a willingness-to-pay threshold of $80,000 per QALY. The strategy with the highest net monetary benefit was considered the most cost-effective. Extensive deterministic and probabilistic sensitivity analyses were performed to explore the effect of varying parameter values. In the reference case analysis, CTA dominated all other imaging strategies. CTA yielded 0.02 QALYs more than magnetic resonance imaging and 0.04 QALYs more than duplex ultrasound followed by CTA. At a willingness-to-pay threshold of $80,000 per QALY, CTA yielded the highest net monetary benefits. The probability that CTA is cost-effective was 96% at a willingness-to-pay threshold of $80,000/QALY. Sensitivity analyses showed that duplex ultrasound was cost-effective only for a prior probability of ≤0.02 and that these results were only minimally influenced by duplex ultrasound sensitivity and specificity. Nonenhanced CT and magnetic resonance imaging never became the most cost-effective strategy. Our results suggest that CTA in patients with possible basilar artery occlusion is cost-effective. © 2015 The Authors.

Cost-effectiveness analysis of ticagrelor compared to clopidogrel for the treatment of patients with acute coronary syndrome in Colombia.

PubMed

Mejía, Aurelio; Senior, Juan Manuel; Ceballos, Mateo; Atehortúa, Sara; Toro, Juan Manuel; Saldarriaga, Clara; Mejía, María Elena; Ramírez, Carolina

2015-01-01

Acute coronary syndrome is one of the most frequent medical emergencies in developing countries. To determine, from the perspective of the Colombian health system, the cost-effectiveness of ticagrelor compared to clopidogrel for the treatment of patients with acute coronary syndrome. We conducted a cost-effectiveness analysis from the perspective of the Colombian health system comparing ticagrelor and clopidogrel for the treatment of patients with acute coronary syndrome. To estimate the expected costs and outcomes, a Markov model was constructed in which patients could remain stable without experiencing new cardiovascular events, suffer from a new event, or die. For the baseline case, a 10-year time horizon and a discount ratio of 3% for costs and benefits were adopted. The transition probabilities were extracted from the PLATO (Platelet Inhibition and Patient Outcomes) clinical trial. Vital statistics were drawn from the Departmento Administrativo Nacional de Estadística (DANE) and additional information from Colombian patients included in the Access registry. To identify and measure resource use, a standard case was built by consulting guidelines and protocols. Unit costs were obtained from Colombian rate lists. A probabilistic sensitivity analysis was conducted in which costs were represented by a triangular distribution, and the effectiveness through a beta distribution. In the base case, the additional cost per quality-adjusted life-year gained with ticagrelor was COP$ 28,411,503. The results were sensitive to changes in the time horizon and the unit cost of clopidogrel. For a willingness-to-pay equivalent to three times the Colombian per capita gross domestic product, the probability of ticagrelor being cost-effective was 75%. Ticagrelor is a cost-effective strategy for the treatment of patients with acute coronary syndrome in Colombia.

Cost-effectiveness of vaccination against pneumococcal bacteremia among elderly people.

PubMed

Sisk, J E; Moskowitz, A J; Whang, W; Lin, J D; Fedson, D S; McBean, A M; Plouffe, J F; Cetron, M S; Butler, J C

Clinical, epidemiologic, and policy considerations support updating the cost-effectiveness of pneumococcal vaccination for elderly people and targeting the evaluation only to prevention of pneumococcal bacteremia. To assess the implications for medical costs and health effects of vaccination against pneumococcal bacteremia in elderly people. Cost-effectiveness analysis of pneumococcal vaccination compared with no vaccination, from a societal perspective. The elderly population aged 65 years and older in the United States in 3 geographic areas: metropolitan Atlanta, Ga; Franklin County, Ohio; and Monroe County, New York. Incremental medical costs and health effects, expressed in quality-adjusted life-years per person vaccinated. Vaccination was cost saving, ie, it both reduced medical expenses and improved health, for all age groups and geographic areas analyzed in the base case. For people aged 65 years and older, vaccination saved $8.27 and gained 1.21 quality-adjusted days of life per person vaccinated. Vaccination of the 23 million elderly people unvaccinated in 1993 would have gained about 78000 years of healthy life and saved $194 million. In univariate sensitivity analysis, the results remained cost saving except for doubling vaccination costs, including future medical costs of survivors, and lowering vaccination effectiveness. With assumptions most unfavorable to vaccination, cost per quality-adjusted life-year ranged from $35 822 for ages 65 to 74 years to $598 487 for ages 85 years and older. In probabilistic sensitivity analysis, probability intervals were more narrow, with less than 5% probability that the ratio for ages 85 years and older would exceed $100000. Pneumococcal vaccination saves costs in the prevention of bacteremia alone and is greatly underused among the elderly population, on both health and economic grounds. These results support recent recommendations of the Advisory Committee on Immunization Practices and public and private efforts under way to improve vaccination rates.

Cost-effectiveness analysis of varenicline versus existing smoking cessation strategies in Central America and the Caribbean using the BENESCO model.

PubMed

Lutz, Manfred A; Lovato, Pedro; Cuesta, Genaro

2012-02-01

In Central American countries, the economic burden of tobacco has not been assessed. In Costa Rica, a study demonstrated that tobacco-related diseases represent high costs for the health care system. The aim of this study was to assess the cost-effectiveness of varenicline compared with other existing strategies for smoking cessation within a 10-year time horizon in an adult population cohort from Central American and Caribbean countries using the health care payer's perspective. The Benefits of Smoking Cessation on Outcomes simulation model was used for an adult cohort in Costa Rica (n = 2 474 029), Panama (n = 2 249 676), Nicaragua (n = 3 639 948), El Salvador (n = 4 537 803), and the Dominican Republic (n = 6 528 125) (N = 19 429 581). Smoking cessation therapies compared were varenicline (0.5-2 mg/day) versus bupropion (300 mg/day), nicotine replacement therapy (5-15 mg/day), and unaided cessation. Effectiveness measures were: life-years (LYs) gained and quality-adjusted life-years (QALYs) gained. Resource use and cost data were obtained from a country's Ministry of Health and/or Social Security Institutions (2008-2010). The model used a 5% discount rate for costs (expressed in 2010 US$) and health outcomes. Probabilistic sensitivity analyses were conducted and acceptability curves were constructed. Varenicline reduced smoking-related morbidity, mortality, and health care costs in each country included in the study. Accumulatively, mortality in the varenicline arm was reduced by 1190, 1538, and 2902 smoking-related deaths compared with bupropion, nicotine replacement therapy, and unaided cessation, respectively. The net average cost per additional quitter showed that varenicline was cost-saving when compared with competing alternatives. Regarding LYs and QALYs gained in 10 years, varenicline obtained the greatest number of QALYs and LYs in each country, while unaided cessation obtained the fewest. Cost-effectiveness analyses in all 5 countries showed that varenicline was the dominant strategy. Acceptability curves showed that, independent of the willingness to pay, the probability that varenicline is cost-effective was 99% for this region. The results of the probabilistic sensitivity analyses support the robustness of the findings. Smoking cessation therapy with varenicline is cost-saving for the Central American and Caribbean countries included. These results could help to reduce the tobacco-related disease burden and align cost-containment policies.

An overview of engineering concepts and current design algorithms for probabilistic structural analysis

NASA Technical Reports Server (NTRS)

Duffy, S. F.; Hu, J.; Hopkins, D. A.

1995-01-01

The article begins by examining the fundamentals of traditional deterministic design philosophy. The initial section outlines the concepts of failure criteria and limit state functions two traditional notions that are embedded in deterministic design philosophy. This is followed by a discussion regarding safety factors (a possible limit state function) and the common utilization of statistical concepts in deterministic engineering design approaches. Next the fundamental aspects of a probabilistic failure analysis are explored and it is shown that deterministic design concepts mentioned in the initial portion of the article are embedded in probabilistic design methods. For components fabricated from ceramic materials (and other similarly brittle materials) the probabilistic design approach yields the widely used Weibull analysis after suitable assumptions are incorporated. The authors point out that Weibull analysis provides the rare instance where closed form solutions are available for a probabilistic failure analysis. Since numerical methods are usually required to evaluate component reliabilities, a section on Monte Carlo methods is included to introduce the concept. The article concludes with a presentation of the technical aspects that support the numerical method known as fast probability integration (FPI). This includes a discussion of the Hasofer-Lind and Rackwitz-Fiessler approximations.

Model Verification and Validation Concepts for a Probabilistic Fracture Assessment Model to Predict Cracking of Knife Edge Seals in the Space Shuttle Main Engine High Pressure Oxidizer

NASA Technical Reports Server (NTRS)

Pai, Shantaram S.; Riha, David S.

2013-01-01

Physics-based models are routinely used to predict the performance of engineered systems to make decisions such as when to retire system components, how to extend the life of an aging system, or if a new design will be safe or available. Model verification and validation (V&V) is a process to establish credibility in model predictions. Ideally, carefully controlled validation experiments will be designed and performed to validate models or submodels. In reality, time and cost constraints limit experiments and even model development. This paper describes elements of model V&V during the development and application of a probabilistic fracture assessment model to predict cracking in space shuttle main engine high-pressure oxidizer turbopump knife-edge seals. The objective of this effort was to assess the probability of initiating and growing a crack to a specified failure length in specific flight units for different usage and inspection scenarios. The probabilistic fracture assessment model developed in this investigation combined a series of submodels describing the usage, temperature history, flutter tendencies, tooth stresses and numbers of cycles, fatigue cracking, nondestructive inspection, and finally the probability of failure. The analysis accounted for unit-to-unit variations in temperature, flutter limit state, flutter stress magnitude, and fatigue life properties. The investigation focused on the calculation of relative risk rather than absolute risk between the usage scenarios. Verification predictions were first performed for three units with known usage and cracking histories to establish credibility in the model predictions. Then, numerous predictions were performed for an assortment of operating units that had flown recently or that were projected for future flights. Calculations were performed using two NASA-developed software tools: NESSUS(Registered Trademark) for the probabilistic analysis, and NASGRO(Registered Trademark) for the fracture mechanics analysis. The goal of these predictions was to provide additional information to guide decisions on the potential of reusing existing and installed units prior to the new design certification.

Transactional Problem Content in Cost Discounting: Parallel Effects for Probability and Delay

ERIC Educational Resources Information Center

Jones, Stephen; Oaksford, Mike

2011-01-01

Four experiments investigated the effects of transactional content on temporal and probabilistic discounting of costs. Kusev, van Schaik, Ayton, Dent, and Chater (2009) have shown that content other than gambles can alter decision-making behavior even when associated value and probabilities are held constant. Transactions were hypothesized to lead…

Electromagnetic Compatibility (EMC) in Microelectronics.

DTIC Science & Technology

1983-02-01

Fault Tree Analysis", System Saftey Symposium, June 8-9, 1965, Seattle: The Boeing Company . 12. Fussell, J.B., "Fault Tree Analysis-Concepts and...procedure for assessing EMC in microelectronics and for applying DD, 1473 EOiTO OP I, NOV6 IS OESOL.ETE UNCLASSIFIED SECURITY CLASSIFICATION OF THIS...CRITERIA 2.1 Background 2 2.2 The Probabilistic Nature of EMC 2 2.3 The Probabilistic Approach 5 2.4 The Compatibility Factor 6 3 APPLYING PROBABILISTIC

NESSUS/EXPERT - An expert system for probabilistic structural analysis methods

NASA Technical Reports Server (NTRS)

Millwater, H.; Palmer, K.; Fink, P.

1988-01-01

An expert system (NESSUS/EXPERT) is presented which provides assistance in using probabilistic structural analysis methods. NESSUS/EXPERT is an interactive menu-driven expert system that provides information to assist in the use of the probabilistic finite element code NESSUS/FEM and the fast probability integrator. NESSUS/EXPERT was developed with a combination of FORTRAN and CLIPS, a C language expert system tool, to exploit the strengths of each language.

Towards Real-time, On-board, Hardware-Supported Sensor and Software Health Management for Unmanned Aerial Systems

NASA Technical Reports Server (NTRS)

Schumann, Johann; Rozier, Kristin Y.; Reinbacher, Thomas; Mengshoel, Ole J.; Mbaya, Timmy; Ippolito, Corey

2013-01-01

Unmanned aerial systems (UASs) can only be deployed if they can effectively complete their missions and respond to failures and uncertain environmental conditions while maintaining safety with respect to other aircraft as well as humans and property on the ground. In this paper, we design a real-time, on-board system health management (SHM) capability to continuously monitor sensors, software, and hardware components for detection and diagnosis of failures and violations of safety or performance rules during the flight of a UAS. Our approach to SHM is three-pronged, providing: (1) real-time monitoring of sensor and/or software signals; (2) signal analysis, preprocessing, and advanced on the- fly temporal and Bayesian probabilistic fault diagnosis; (3) an unobtrusive, lightweight, read-only, low-power realization using Field Programmable Gate Arrays (FPGAs) that avoids overburdening limited computing resources or costly re-certification of flight software due to instrumentation. Our implementation provides a novel approach of combining modular building blocks, integrating responsive runtime monitoring of temporal logic system safety requirements with model-based diagnosis and Bayesian network-based probabilistic analysis. We demonstrate this approach using actual data from the NASA Swift UAS, an experimental all-electric aircraft.

Cost-effectiveness analysis of infliximab, adalimumab, golimumab and vedolizumab for moderate to severe ulcerative colitis in Spain.

PubMed

Trigo-Vicente, Cristina; Gimeno-Ballester, Vicente; Montoiro-Allué, Raquel; López-Del Val, Alejandro

2017-12-02

Assess the efficiency of biologic treatment for moderate to severe ulcerative colitis (UC) which are indicated and financed for this pathology by Spain. A Markov model was constructed to simulate the progression in a cohort of patients with moderate to severe UC. The perspective chosen was National Health Service with an over 10 years of time horizon, with a discount rate of 3%, and established threshold of €30,000/quality-adjusted life-year (QALY). The comparison between infliximab versus adalimumab achieved an incremental cost-effectiveness ratio (ICER) of €45,582/QALY, with a 0.900 QALYs difference of efficacy and an incremental cost of €41,036. Golimumab versus adalimumab reached an ICER of €2,175,992/QALY, with a difference of 0.001 QALY in efficacy and a raising cost to €2,611. The comparison between vedolizumab with adalimumab achieved an ICER of €90,532/QALY, 0.930 QALYs of difference and an increasing cost of €84,218. The probabilistic sensitivity analysis shows that adalimumab would be cost-effective in the 65.2% of the simulations, infliximab in the 18.4%, golimumab in the 16.4% and vedulizumab for the 0%. Among all these drugs studied, adalimumab is the most cost-effective drug for the treatment of moderate to severe UC for a threshold of €30,000/QALY in Spain.

Probabilistic sizing of laminates with uncertainties

NASA Technical Reports Server (NTRS)

Shah, A. R.; Liaw, D. G.; Chamis, C. C.

1993-01-01

A reliability based design methodology for laminate sizing and configuration for a special case of composite structures is described. The methodology combines probabilistic composite mechanics with probabilistic structural analysis. The uncertainties of constituent materials (fiber and matrix) to predict macroscopic behavior are simulated using probabilistic theory. Uncertainties in the degradation of composite material properties are included in this design methodology. A multi-factor interaction equation is used to evaluate load and environment dependent degradation of the composite material properties at the micromechanics level. The methodology is integrated into a computer code IPACS (Integrated Probabilistic Assessment of Composite Structures). Versatility of this design approach is demonstrated by performing a multi-level probabilistic analysis to size the laminates for design structural reliability of random type structures. The results show that laminate configurations can be selected to improve the structural reliability from three failures in 1000, to no failures in one million. Results also show that the laminates with the highest reliability are the least sensitive to the loading conditions.

Distributed collaborative probabilistic design for turbine blade-tip radial running clearance using support vector machine of regression

NASA Astrophysics Data System (ADS)

Fei, Cheng-Wei; Bai, Guang-Chen

2014-12-01

To improve the computational precision and efficiency of probabilistic design for mechanical dynamic assembly like the blade-tip radial running clearance (BTRRC) of gas turbine, a distribution collaborative probabilistic design method-based support vector machine of regression (SR)(called as DCSRM) is proposed by integrating distribution collaborative response surface method and support vector machine regression model. The mathematical model of DCSRM is established and the probabilistic design idea of DCSRM is introduced. The dynamic assembly probabilistic design of aeroengine high-pressure turbine (HPT) BTRRC is accomplished to verify the proposed DCSRM. The analysis results reveal that the optimal static blade-tip clearance of HPT is gained for designing BTRRC, and improving the performance and reliability of aeroengine. The comparison of methods shows that the DCSRM has high computational accuracy and high computational efficiency in BTRRC probabilistic analysis. The present research offers an effective way for the reliability design of mechanical dynamic assembly and enriches mechanical reliability theory and method.

Cost-utility analysis for bariatric surgery compared with usual care for the treatment of obesity in Australia.

PubMed

James, Robbie; Salton, Ryan Ishmael; Byrnes, Joshua Michael; Scuffham, Paul Anthony

2017-12-01

The uptake of bariatric surgery in Australia has been hampered by the lack of funding and lack of evidence on relative value for money. To determine the cost-effectiveness of adjustable gastric banding (AGB), Roux-En-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) versus usual care (UC). Perspective of the Australian public healthcare system. A Markov model was constructed to simulate the costs and outcomes for 4 approaches to managing obesity. The base-case was a 30-year-old Australian female with a body-mass index>35. Subgroup analysis was conducted to account for the effect of diabetes as well as various differences in cohort characteristics. Uncertainty was characterised by one-way and probabilistic sensitivity analyses. All bariatric surgeries were effective. The incremental cost-effectiveness ratios were similar at $24,454 for AGB, $22,645 for RYGB, and $27,523 for SG, compared with UC. At a willingness to pay threshold of $70,000 per quality-adjusted life year, the probabilities of being cost-effective were 64%, 75%, and 71% for AGB, RYGB, and SG, respectively. Subgroup analysis showed that bariatric procedures are less cost-effective for older cohorts. For those with diabetes, all the procedures were dominant in comparison with UC. This model shows that all bariatric procedures are a cost-effective treatment for the management of obese patients. When given to a subgroup with diabetes, bariatric interventions become cost-saving. Copyright © 2017 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Economic evaluation of an implementation strategy for the management of low back pain in general practice.

PubMed

Jensen, Cathrine Elgaard; Riis, Allan; Petersen, Karin Dam; Jensen, Martin Bach; Pedersen, Kjeld Møller

2017-05-01

In connection with the publication of a clinical practice guideline on the management of low back pain (LBP) in general practice in Denmark, a cluster randomised controlled trial was conducted. In this trial, a multifaceted guideline implementation strategy to improve general practitioners' treatment of patients with LBP was compared with a usual implementation strategy. The aim was to determine whether the multifaceted strategy was cost effective, as compared with the usual implementation strategy. The economic evaluation was conducted as a cost-utility analysis where cost collected from a societal perspective and quality-adjusted life years were used as outcome measures. The analysis was conducted as a within-trial analysis with a 12-month time horizon consistent with the follow-up period of the clinical trial. To adjust for a priori selected covariates, generalised linear models with a gamma family were used to estimate incremental costs and quality-adjusted life years. Furthermore, both deterministic and probabilistic sensitivity analyses were conducted. Results showed that costs associated with primary health care were higher, whereas secondary health care costs were lower for the intervention group when compared with the control group. When adjusting for covariates, the intervention was less costly, and there was no significant difference in effect between the 2 groups. Sensitivity analyses showed that results were sensitive to uncertainty. In conclusion, the multifaceted implementation strategy was cost saving when compared with the usual strategy for implementing LBP clinical practice guidelines in general practice. Furthermore, there was no significant difference in effect, and the estimate was sensitive to uncertainty.

Determining the Optimal Vaccination Schedule for Herpes Zoster: a Cost-Effectiveness Analysis.

PubMed

Le, Phuc; Rothberg, Michael B

2017-02-01

The Advisory Committee on Immunization Practices recommends a single dose of herpes zoster (HZ) vaccine in persons aged 60 years or older, but the efficacy decreases to zero after approximately 10 years. A booster dose administered after 10 years might extend protection, but the cost-effectiveness of a booster strategy has not been examined. We aimed to determine the optimal schedule for HZ vaccine DESIGN: We built a Markov model to follow patients over their lifetime. From the societal perspective, we compared costs and quality-adjusted life years (QALYs) saved of 11 strategies to start and repeat HZ vaccine at different ages. Adults aged 60 years. HZ vaccine. Costs, quality-adjusted life years (QALYs), and incremental costs per QALY saved. At a $100,000/QALY threshold, "vaccination at 70 plus one booster" was the most cost-effective strategy, with an incremental cost-effectiveness ratio (ICER) of $36,648/QALY. "Vaccination at 60 plus two boosters" was more effective, but had an ICER of $153,734/QALY. In deterministic sensitivity analysis, "vaccination at 60 plus two boosters" cost < $100,000/QALY if compliance rate was > 67 % or vaccine cost was < $156 per dose. In probabilistic sensitivity analysis, "vaccination at 70 plus one booster" was preferred at a willingness-to-pay of up to $135,000/QALY. Under current assumptions, initiating HZ vaccine at age 70 years with one booster dose 10 years later appears optimal. Future data regarding compliance with or efficacy of a booster could affect these conclusions.

[The Probabilistic Efficiency Frontier: A Value Assessment of Treatment Options in Hepatitis C].

PubMed

Mühlbacher, Axel C; Sadler, Andrew

2017-06-19

Background The German Institute for Quality and Efficiency in Health Care (IQWiG) recommends the concept of the efficiency frontier to assess health care interventions. The efficiency frontier supports regulatory decisions on reimbursement prices for the appropriate allocation of health care resources. Until today this cost-benefit assessment framework has only been applied on the basis of individual patient-relevant endpoints. This contradicts the reality of a multi-dimensional patient benefit. Objective The objective of this study was to illustrate the operationalization of multi-dimensional benefit considering the uncertainty in clinical effects and preference data in order to calculate the efficiency of different treatment options for hepatitis C (HCV). This case study shows how methodological challenges could be overcome in order to use the efficiency frontier for economic analysis and health care decision-making. Method The operationalization of patient benefit was carried out on several patient-relevant endpoints. Preference data from a discrete choice experiment (DCE) study and clinical data based on clinical trials, which reflected the patient and the clinical perspective, respectively, were used for the aggregation of an overall benefit score. A probabilistic efficiency frontier was constructed in a Monte Carlo simulation with 10000 random draws. Patient-relevant endpoints were modeled with a beta distribution and preference data with a normal distribution. The assessment of overall benefit and costs provided information about the adequacy of the treatment prices. The parameter uncertainty was illustrated by the price-acceptability-curve and the net monetary benefit. Results Based on the clinical and preference data in Germany, the interferon-free treatment options proved to be efficient for the current price level. The interferon-free therapies of the latest generation achieved a positive net cost-benefit. Within the decision model, these therapies showed a maximum overall benefit. Due to their high additional benefit and approved prices, the therapies lie above of the extrapolated efficiency frontier, which suggests that these options have efficient reimbursement prices. Considering uncertainty, even a higher price would have resulted in a positive cost-benefit ratio. Conclusion IQWiG's efficiency frontier was used to assess the value of different treatment options in HCV. This study demonstrates that the probabilistic efficiency frontier, price-acceptability-curve and the net monetary benefit can contribute essential information to reimbursement decisions and price negotiations. © Georg Thieme Verlag KG Stuttgart · New York.

Proposal of a method for evaluating tsunami risk using response-surface methodology

NASA Astrophysics Data System (ADS)

Fukutani, Y.

2017-12-01

Information on probabilistic tsunami inundation hazards is needed to define and evaluate tsunami risk. Several methods for calculating these hazards have been proposed (e.g. Løvholt et al. (2012), Thio (2012), Fukutani et al. (2014), Goda et al. (2015)). However, these methods are inefficient, and their calculation cost is high, since they require multiple tsunami numerical simulations, therefore lacking versatility. In this study, we proposed a simpler method for tsunami risk evaluation using response-surface methodology. Kotani et al. (2016) proposed an evaluation method for the probabilistic distribution of tsunami wave-height using a response-surface methodology. We expanded their study and developed a probabilistic distribution of tsunami inundation depth. We set the depth (x1) and the slip (x2) of an earthquake fault as explanatory variables and tsunami inundation depth (y) as an object variable. Subsequently, tsunami risk could be evaluated by conducting a Monte Carlo simulation, assuming that the generation probability of an earthquake follows a Poisson distribution, the probability distribution of tsunami inundation depth follows the distribution derived from a response-surface, and the damage probability of a target follows a log normal distribution. We applied the proposed method to a wood building located on the coast of Tokyo Bay. We implemented a regression analysis based on the results of 25 tsunami numerical calculations and developed a response-surface, which was defined as y=ax1+bx2+c (a:0.2615, b:3.1763, c=-1.1802). We assumed proper probabilistic distribution for earthquake generation, inundation height, and vulnerability. Based on these probabilistic distributions, we conducted Monte Carlo simulations of 1,000,000 years. We clarified that the expected damage probability of the studied wood building is 22.5%, assuming that an earthquake occurs. The proposed method is therefore a useful and simple way to evaluate tsunami risk using a response-surface and Monte Carlo simulation without conducting multiple tsunami numerical simulations.

Scheduling structural health monitoring activities for optimizing life-cycle costs and reliability of wind turbines

NASA Astrophysics Data System (ADS)

Hanish Nithin, Anu; Omenzetter, Piotr

2017-04-01

Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Most of the existing studies have used structural reliability and the Bayesian pre-posterior analysis for optimization. This paper proposes an extension to the previous approaches in a framework for probabilistic optimization of the total life-cycle costs and reliability of OWTs by combining the elements of structural reliability/risk analysis (SRA), the Bayesian pre-posterior analysis with optimization through a genetic algorithm (GA). The SRA techniques are adopted to compute the probabilities of damage occurrence and failure associated with the deterioration model. The probabilities are used in the decision tree and are updated using the Bayesian analysis. The output of this framework would determine the optimal structural health monitoring and maintenance schedules to be implemented during the life span of OWTs while maintaining a trade-off between the life-cycle costs and risk of the structural failure. Numerical illustrations with a generic deterioration model for one monitoring exercise in the life cycle of a system are demonstrated. Two case scenarios, namely to build initially an expensive and robust or a cheaper but more quickly deteriorating structures and to adopt expensive monitoring system, are presented to aid in the decision-making process.

Parallel computing for probabilistic fatigue analysis

NASA Technical Reports Server (NTRS)

Sues, Robert H.; Lua, Yuan J.; Smith, Mark D.

1993-01-01

This paper presents the results of Phase I research to investigate the most effective parallel processing software strategies and hardware configurations for probabilistic structural analysis. We investigate the efficiency of both shared and distributed-memory architectures via a probabilistic fatigue life analysis problem. We also present a parallel programming approach, the virtual shared-memory paradigm, that is applicable across both types of hardware. Using this approach, problems can be solved on a variety of parallel configurations, including networks of single or multiprocessor workstations. We conclude that it is possible to effectively parallelize probabilistic fatigue analysis codes; however, special strategies will be needed to achieve large-scale parallelism to keep large number of processors busy and to treat problems with the large memory requirements encountered in practice. We also conclude that distributed-memory architecture is preferable to shared-memory for achieving large scale parallelism; however, in the future, the currently emerging hybrid-memory architectures will likely be optimal.

Probabilistic Parameter Uncertainty Analysis of Single Input Single Output Control Systems

NASA Technical Reports Server (NTRS)

Smith, Brett A.; Kenny, Sean P.; Crespo, Luis G.

2005-01-01

The current standards for handling uncertainty in control systems use interval bounds for definition of the uncertain parameters. This approach gives no information about the likelihood of system performance, but simply gives the response bounds. When used in design, current methods of m-analysis and can lead to overly conservative controller design. With these methods, worst case conditions are weighted equally with the most likely conditions. This research explores a unique approach for probabilistic analysis of control systems. Current reliability methods are examined showing the strong areas of each in handling probability. A hybrid method is developed using these reliability tools for efficiently propagating probabilistic uncertainty through classical control analysis problems. The method developed is applied to classical response analysis as well as analysis methods that explore the effects of the uncertain parameters on stability and performance metrics. The benefits of using this hybrid approach for calculating the mean and variance of responses cumulative distribution functions are shown. Results of the probabilistic analysis of a missile pitch control system, and a non-collocated mass spring system, show the added information provided by this hybrid analysis.

Cost-effectiveness analysis of exenatide twice daily (BID) vs insulin glargine once daily (QD) as add-on therapy in Chinese patients with Type 2 diabetes mellitus inadequately controlled by oral therapies.

PubMed

Deng, Jing; Gu, Shuyan; Shao, Hui; Dong, Hengjin; Zou, Dajin; Shi, Lizheng

2015-01-01

To estimate cost-effectiveness of exenatide twice daily (BID) vs insulin glargine once daily (QD) as add-on therapy in Chinese type 2 diabetes patients not well controlled by oral anti-diabetic (OAD) agents. The Cardiff model was populated with data synthesized from three head-to-head randomized clinical trials of up to 30 weeks in China comparing exenatide BID vs insulin glargine as add-on therapies to oral therapies in the Chinese population. The Cardiff model generated outputs including macrovascular and microvascular complications, diabetes-specific mortality, costs, and quality-adjusted life years (QALYs). Cost and QALYs were estimated with a time horizon of 40 years at a discount rate of 3% from a societal perspective. Compared with insulin glargine plus OAD treatments, patients on exenatide BID plus OAD gained 1.88 QALYs, at an incremental cost saving of Chinese Renminbi (RMB) 114,593 (i.e., cost saving of RMB 61078/QALY). The cost-effectiveness results were robust to various sensitivity analyses including probabilistic sensitivity analysis. The variables with the most impact on incremental cost-effectiveness ratio included HbA1c level at baseline, health utilities decrement, and BMI at baseline. Compared with insulin glargine QD, exenatide BID as add-on therapy to OAD is a cost-effective treatment in Chinese patients inadequately controlled by OAD treatments.

Probabilistic structural analysis methods for space transportation propulsion systems

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Moore, N.; Anis, C.; Newell, J.; Nagpal, V.; Singhal, S.

1991-01-01

Information on probabilistic structural analysis methods for space propulsion systems is given in viewgraph form. Information is given on deterministic certification methods, probability of failure, component response analysis, stress responses for 2nd stage turbine blades, Space Shuttle Main Engine (SSME) structural durability, and program plans. .

Cost-effectiveness analysis evaluating fidaxomicin versus oral vancomycin for the treatment of Clostridium difficile infection in the United States.

PubMed

Stranges, Paul M; Hutton, David W; Collins, Curtis D

2013-01-01

Fidaxomicin is a novel treatment for Clostridium difficile infections (CDIs). This new treatment, however, is associated with a higher acquisition cost compared with alternatives. The objective of this study was to evaluate the cost-effectiveness of fidaxomicin or oral vancomycin for the treatment of CDIs. We performed a cost-utility analysis comparing fidaxomicin with oral vancomycin for the treatment of CDIs in the United States by creating a decision analytic model from the third-party payer perspective. The incremental cost-effectiveness ratio with fidaxomicin compared with oral vancomycin was $67,576/quality-adjusted life-year. A probabilistic Monte Carlo sensitivity analysis showed that fidaxomicin had an 80.2% chance of being cost-effective at a willingness-to-pay threshold of $100,000/quality-adjusted life-year. Fidaxomicin remained cost-effective under all fluctuations of both fidaxomicin and oral vancomycin costs. The decision analytic model was sensitive to variations in clinical cure and recurrence rates. Secondary analyses revealed that fidaxomicin was cost-effective in patients receiving concominant antimicrobials, in patients with mild to moderate CDIs, and when compared with oral metronidazole in patients with mild to moderate disease. Fidaxomicin was dominated by oral vancomycin if CDI was caused by the NAP1/Bl/027 Clostridium difficile strain and was dominant in institutions that did not compound oral vancomycin. Results of our model showed that fidaxomicin may be a more cost-effective option for the treatment of CDIs when compared with oral vancomycin under most scenarios tested. Copyright © 2013 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Cost-effectiveness of prenatal screening strategies for congenital heart disease.

PubMed

Pinto, N M; Nelson, R; Puchalski, M; Metz, T D; Smith, K J

2014-07-01

The economic implications of strategies to improve prenatal screening for congenital heart disease (CHD) in low-risk mothers have not been explored. The aim was to perform a cost-effectiveness analysis of different screening methods. We constructed a decision analytic model of CHD prenatal screening strategies (four-chamber screen (4C), 4C + outflow, nuchal translucency (NT) or fetal echocardiography) populated with probabilities from the literature. The model included whether initial screens were interpreted by a maternal-fetal medicine (MFM) specialist and different referral strategies if they were read by a non-MFM specialist. The primary outcome was the incremental cost per defect detected. Costs were obtained from Medicare National Fee estimates. A probabilistic sensitivity analysis was undertaken on model variables commensurate with their degree of uncertainty. In base-case analysis, 4C + outflow referred to an MFM specialist was the least costly strategy per defect detected. The 4C screen and the NT screen were dominated by other strategies (i.e. were more costly and less effective). Fetal echocardiography was the most effective, but most costly. On simulation of 10 000 low-risk pregnancies, 4C + outflow screen referred to an MFM specialist remained the least costly per defect detected. For an additional $580 per defect detected, referral to cardiology after a 4C + outflow was the most cost-effective for the majority of iterations, increasing CHD detection by 13 percentage points. The addition of examination of the outflow tracts to second-trimester ultrasound increases detection of CHD in the most cost-effective manner. Strategies to improve outflow-tract imaging and to refer with the most efficiency may be the best way to improve detection at a population level. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

The combined use of surgery and radiotherapy to treat patients with epidural cord compression due to metastatic disease: a cost-utility analysis

PubMed Central

Furlan, Julio C.; Chan, Kelvin K.-W.; Sandoval, Guillermo A.; Lam, Kenneth C. K.; Klinger, Christopher A.; Patchell, Roy A.; Laporte, Audrey; Fehlings, Michael G.

2012-01-01

Neoplastic metastatic epidural spinal cord compression is a common complication of cancer that causes pain and progressive neurologic impairment. The previous standard treatment for this condition involved corticosteroids and radiotherapy (RT). Direct decompressive surgery with postoperative radiotherapy (S + RT) is now increasingly being chosen by clinicians to significantly improve patients’ ability to walk and reduce their need for opioid analgesics and corticosteroids. A cost-utility analysis was conducted to compare S + RT with RT alone based on the landmark randomized clinical trial by Patchell et al. (2005). It was performed from the perspective of the Ontario Ministry of Health and Long-Term Care. Ontario-based costs were adjusted to 2010 US dollars. S + RT is more costly but also more effective than corticosteroids and RT alone, with an incremental cost-effectiveness ratio of US$250 307 per quality-adjusted life year (QALY) gained. First order probabilistic sensitivity analysis revealed that the probability of S + RT being cost-effective is 18.11%. The cost-effectiveness acceptability curve showed that there is a 91.11% probability of S + RT being cost-effective over RT alone at a willingness-to-pay of US$1 683 000 per QALY. In practice, the results of our study indicate that, by adopting the S + RT strategy, there would still be a chance of 18.11% of not paying extra at a willingness-to-pay of US$50 000 per QALY. Those results are sensitive to the costs of hospice palliative care. Our results suggest that adopting a standard S + RT approach for patients with MSCC is likely to increase health care costs but would result in improved outcomes. PMID:22505658

A Cost-Effectiveness Analysis of Gemcitabine plus Cisplatin Versus Gemcitabine Alone for Treatment of Advanced Biliary Tract Cancer in Japan.

PubMed

Tsukiyama, Ikuto; Ejiri, Masayuki; Yamamoto, Yoshihiro; Nakao, Haruhisa; Yoneda, Masashi; Matsuura, Katsuhiko; Arakawa, Ichiro; Saito, Hiroko; Inoue, Tadao

2017-12-01

This study assessed the cost-effectiveness of combination treatment with gemcitabine and cisplatin compared to treatment with gemcitabine alone for advanced biliary tract cancer (BTC) in Japan. A monthly transmitted Markov model of three states was constructed based on the Japan BT-22 trial. Transition probabilities among the health states were derived from a trial conducted in Japan and converted to appropriate parameters for our model. The associated cost components, obtained from a receipt-based survey undertaken at the Aichi Medical University Hospital, were those related to inpatient care, outpatient care, and treatment for BTC. Costs for palliative care and treatment of adverse events were obtained from the National Health Insurance price list. We estimated cost-effectiveness per quality-adjusted life year (QALY) at a time horizon of 36 months. An annual discount of 3 % for both cost and outcome was considered. The base case outcomes indicated that combination therapy was less cost-effective than monotherapy when the incremental cost-effectiveness ratio (ICER) was approximately 14 million yen per QALY gained. The deterministic sensitivity analysis of the ICER revealed that the ICER of the base case was robust. A probabilistic analysis conducted with 10,000-time Monte Carlo simulations demonstrated efficacy at the willingness to pay threshold of 6 million yen per QALY gained for approximately 33 % of the population. In Japan, combination therapy is less cost-effective than monotherapy for treating advanced BTC, regardless of the statistical significance of the two therapies. Useful information on the cost-effectiveness of chemotherapy is much needed for the treatment of advanced BTC in Japan.

COST-UTILITY ANALYSIS OF PRIMARY PROPHYLAXIS, COMPARED WITH ON-DEMAND TREATMENT, FOR PATIENTS WITH SEVERE HEMOPHILIA TYPE A IN COLOMBIA.

PubMed

Castro Jaramillo, Héctor Eduardo; Moreno Viscaya, Mabel; Mejia, Aurelio E

2016-01-01

This article presents a cost-utility analysis from the Colombian health system perspective comparing primary prophylaxis to on-demand treatment using exogenous clotting factor VIII (FVIII) for patients with severe hemophilia type A. We developed a Markov model to estimate expected costs and outcomes (measured as quality-adjusted life-years, QALYs) for each strategy. Transition probabilities were estimated using published studies; utility weights were obtained from a sample of Colombian patients with hemophilia and costs were gathered using local data. Both deterministic and probabilistic sensitivity analysis were performed to assess the robustness of results. The additional cost per QALY gained of primary prophylaxis compared with on-demand treatment was 105,081,022 Colombian pesos (COP) (55,204 USD), and thus not considered cost-effective according to a threshold of up to three times the current Colombian gross domestic product (GDP) per-capita. When primary prophylaxis was provided throughout life using recombinant FVIII (rFVIII), which is much costlier than FVIII, the additional cost per QALY gained reached 174,159,553 COP (91,494 USD). using a decision rule of up to three times the Colombian GDP per capita, primary prophylaxis (with either FVIII or rFVIII) would not be considered as cost-effective in this country. However, a final decision on providing or preventing patients from primary prophylaxis as a gold standard of care for severe hemophilia type A should also consider broader criteria than the incremental cost-effectiveness ratio results itself. Only a price reduction of exogenous FVIII of 50 percent or more would make primary prophylaxis cost-effective in this context.

Characterizing uncertain sea-level rise projections to support investment decisions.

PubMed

Sriver, Ryan L; Lempert, Robert J; Wikman-Svahn, Per; Keller, Klaus

2018-01-01

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments. Results highlight the highly-localized and context dependent nature of applying Robust Decision Making methods to inform investment decisions.

Characterizing uncertain sea-level rise projections to support investment decisions

PubMed Central

Lempert, Robert J.; Wikman-Svahn, Per; Keller, Klaus

2018-01-01

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments. Results highlight the highly-localized and context dependent nature of applying Robust Decision Making methods to inform investment decisions. PMID:29414978

Sensitivity analysis in economic evaluation: an audit of NICE current practice and a review of its use and value in decision-making.

PubMed

Andronis, L; Barton, P; Bryan, S

2009-06-01

To determine how we define good practice in sensitivity analysis in general and probabilistic sensitivity analysis (PSA) in particular, and to what extent it has been adhered to in the independent economic evaluations undertaken for the National Institute for Health and Clinical Excellence (NICE) over recent years; to establish what policy impact sensitivity analysis has in the context of NICE, and policy-makers' views on sensitivity analysis and uncertainty, and what use is made of sensitivity analysis in policy decision-making. Three major electronic databases, MEDLINE, EMBASE and the NHS Economic Evaluation Database, were searched from inception to February 2008. The meaning of 'good practice' in the broad area of sensitivity analysis was explored through a review of the literature. An audit was undertaken of the 15 most recent NICE multiple technology appraisal judgements and their related reports to assess how sensitivity analysis has been undertaken by independent academic teams for NICE. A review of the policy and guidance documents issued by NICE aimed to assess the policy impact of the sensitivity analysis and the PSA in particular. Qualitative interview data from NICE Technology Appraisal Committee members, collected as part of an earlier study, were also analysed to assess the value attached to the sensitivity analysis components of the economic analyses conducted for NICE. All forms of sensitivity analysis, notably both deterministic and probabilistic approaches, have their supporters and their detractors. Practice in relation to univariate sensitivity analysis is highly variable, with considerable lack of clarity in relation to the methods used and the basis of the ranges employed. In relation to PSA, there is a high level of variability in the form of distribution used for similar parameters, and the justification for such choices is rarely given. Virtually all analyses failed to consider correlations within the PSA, and this is an area of concern. Uncertainty is considered explicitly in the process of arriving at a decision by the NICE Technology Appraisal Committee, and a correlation between high levels of uncertainty and negative decisions was indicated. The findings suggest considerable value in deterministic sensitivity analysis. Such analyses serve to highlight which model parameters are critical to driving a decision. Strong support was expressed for PSA, principally because it provides an indication of the parameter uncertainty around the incremental cost-effectiveness ratio. The review and the policy impact assessment focused exclusively on documentary evidence, excluding other sources that might have revealed further insights on this issue. In seeking to address parameter uncertainty, both deterministic and probabilistic sensitivity analyses should be used. It is evident that some cost-effectiveness work, especially around the sensitivity analysis components, represents a challenge in making it accessible to those making decisions. This speaks to the training agenda for those sitting on such decision-making bodies, and to the importance of clear presentation of analyses by the academic community.

Cost-effectiveness analysis of online hemodiafiltration versus high-flux hemodialysis.

PubMed

Ramponi, Francesco; Ronco, Claudio; Mason, Giacomo; Rettore, Enrico; Marcelli, Daniele; Martino, Francesca; Neri, Mauro; Martin-Malo, Alejandro; Canaud, Bernard; Locatelli, Francesco

2016-01-01

Clinical studies suggest that hemodiafiltration (HDF) may lead to better clinical outcomes than high-flux hemodialysis (HF-HD), but concerns have been raised about the cost-effectiveness of HDF versus HF-HD. Aim of this study was to investigate whether clinical benefits, in terms of longer survival and better health-related quality of life, are worth the possibly higher costs of HDF compared to HF-HD. The analysis comprised a simulation based on the combined results of previous published studies, with the following steps: 1) estimation of the survival function of HF-HD patients from a clinical trial and of HDF patients using the risk reduction estimated in a meta-analysis; 2) simulation of the survival of the same sample of patients as if allocated to HF-HD or HDF using three-state Markov models; and 3) application of state-specific health-related quality of life coefficients and differential costs derived from the literature. Several Monte Carlo simulations were performed, including simulations for patients with different risk profiles, for example, by age (patients aged 40, 50, and 60 years), sex, and diabetic status. Scatter plots of simulations in the cost-effectiveness plane were produced, incremental cost-effectiveness ratios were estimated, and cost-effectiveness acceptability curves were computed. An incremental cost-effectiveness ratio of €6,982/quality-adjusted life years (QALY) was estimated for the baseline cohort of 50-year-old male patients. Given the commonly accepted threshold of €40,000/QALY, HDF is cost-effective. The probabilistic sensitivity analysis showed that HDF is cost-effective with a probability of ~81% at a threshold of €40,000/QALY. It is fundamental to measure the outcome also in terms of quality of life. HDF is more cost-effective for younger patients. HDF can be considered cost-effective compared to HF-HD.

Cost-effectiveness of uterine-preserving procedures for the treatment of uterine fibroid symptoms in the USA.

PubMed

Cain-Nielsen, Anne H; Moriarty, James P; Stewart, Elizabeth A; Borah, Bijan J

2014-09-01

To evaluate the cost-effectiveness of the following three treatments of uterine fibroids in a population of premenopausal women who wish to preserve their uteri: myomectomy, magnetic resonance-guided focused ultrasound (MRgFUS) and uterine artery embolization (UAE). A decision analytic Markov model was constructed. Cost-effectiveness was calculated in terms of US$ per quality-adjusted life year (QALY) over 5 years. Two types of costs were calculated: direct costs only, and the sum of direct and indirect (productivity) costs. Women in the hypothetical cohort were assessed for treatment type eligibility, were treated based on eligibility, and experienced adequate or inadequate symptom relief. Additional treatment (myomectomy) occurred for inadequate symptom relief or recurrence. Sensitivity analysis was conducted to evaluate uncertainty in the model parameters.  In the base case, myomectomy, MRgFUS and UAE had the following combinations of mean cost and mean QALYs, respectively: US$15,459, 3.957; US$15,274, 3.953; and US$18,653, 3.943. When incorporating productivity costs, MRgFUS incurred a mean cost of US$21,232; myomectomy US$22,599; and UAE US$22,819. Using probabilistic sensitivity analysis (PSA) and excluding productivity costs, myomectomy was cost effective at almost every decision threshold. Using PSA and incorporating productivity costs, myomectomy was cost effective at decision thresholds above US$105,000/QALY; MRgFUS was cost effective between US$30,000 and US$105,000/QALY; and UAE was cost effective below US$30,000/QALY. Myomectomy, MRgFUS, and UAE were similarly effective in terms of QALYs gained. Depending on assumptions about costs and willingness to pay for additional QALYs, all three treatments can be deemed cost effective in a 5-year time frame.

Cost-effectiveness of high-dose versus standard-dose inactivated influenza vaccine in adults aged 65 years and older: an economic evaluation of data from a randomised controlled trial.

PubMed

Chit, Ayman; Becker, Debbie L; DiazGranados, Carlos A; Maschio, Michael; Yau, Eddy; Drummond, Michael

2015-12-01

Adults aged 65 years and older account for most seasonal influenza-related hospital admissions and deaths. Findings from the randomised controlled FIM12 study showed that high-dose inactivated influenza vaccine is more effective than standard-dose vaccine for prevention of laboratory-confirmed influenza in this age group. We aimed to assess the economic impact of high-dose versus standard-dose influenza vaccine in participants in the FIM12 study population. The FIM12 study was a head-to-head randomised controlled trial in which 31,989 participants aged 65 years and older were randomly assigned (1:1) to receive either high-dose or standard-dose trivalent inactivated influenza vaccine over two influenza seasons (2011-12 and 2012-13). Data for health-care resource consumption obtained in the FIM12 study were summarised across vaccine groups. Unit costs obtained from standard US cost sources were applied to each resource item, including to the vaccines (high dose US$31·82, standard dose $12·04). Clinical illness data were mapped to existing quality-of-life data. The time horizon was one influenza season; however, quality-adjusted life-years (QALYs) lost due to death during the study were calculated over a lifetime. We calculated incremental cost-effectiveness ratios (ICERs) for high-dose versus standard-dose vaccine and used QALYs as an outcome in the cost-utility analysis. We undertook a probabilistic sensitivity analysis using bootstrapping to explore the effect of statistical uncertainty on the study results. Mean per-participant medical costs were lower in the high-dose vaccine group ($1376·72 [SD 6857·59]) than in the standard-dose group ($1492·64 [7447·14]; difference -$115·92 [95% CI -264·18 to 35·48]). Mean societal costs were likewise lower in the high-dose versus the standard-dose group ($1506·48 [SD 7305·19] vs $1634·50 [7952·99]; difference -$128·02 [95% CI -286·89 to 33·30]). Hospital admissions contributed 95% of the total health-care-payer cost and 87% of the total societal costs. The mean per-participant number of hospital admissions was 0·0937 (SD 0·3644) in the high-dose group and 0·1017 (0·3708) in the standard-dose group (difference -0·0080, 95% CI -0·0160 to -0·0003). The high-dose vaccine provided a gain in QALYs (mean 8·1502 QALYs gained per participant [SD 0·5693]) compared with the standard-dose vaccine (8·1499 QALYs [0·5697]) and, due to cost savings, dominated standard-dose vaccine in the cost-utility analysis. The probabilistic sensitivity analysis showed that the high-dose vaccine is 93% likely to be cost saving. High-dose trivalent inactivated influenza vaccine is a less costly and more effective alternative to the standard-dose vaccine, driven by a reduction in the number of hospital admissions. These findings are relevant to US health-care beneficiaries, providers, payers, and recommending bodies, especially those seeking to improve outcomes while containing costs. Sanofi Pasteur. Copyright © 2015 Elsevier Ltd. All rights reserved.

Time-varying loss forecast for an earthquake scenario in Basel, Switzerland

NASA Astrophysics Data System (ADS)

Herrmann, Marcus; Zechar, Jeremy D.; Wiemer, Stefan

2014-05-01

When an unexpected earthquake occurs, people suddenly want advice on how to cope with the situation. The 2009 L'Aquila quake highlighted the significance of public communication and pushed the usage of scientific methods to drive alternative risk mitigation strategies. For instance, van Stiphout et al. (2010) suggested a new approach for objective evacuation decisions on short-term: probabilistic risk forecasting combined with cost-benefit analysis. In the present work, we apply this approach to an earthquake sequence that simulated a repeat of the 1356 Basel earthquake, one of the most damaging events in Central Europe. A recent development to benefit society in case of an earthquake are probabilistic forecasts of the aftershock occurrence. But seismic risk delivers a more direct expression of the socio-economic impact. To forecast the seismic risk on short-term, we translate aftershock probabilities to time-varying seismic hazard and combine this with time-invariant loss estimation. Compared with van Stiphout et al. (2010), we use an advanced aftershock forecasting model and detailed settlement data to allow us spatial forecasts and settlement-specific decision-making. We quantify the risk forecast probabilistically in terms of human loss. For instance one minute after the M6.6 mainshock, the probability for an individual to die within the next 24 hours is 41 000 times higher than the long-term average; but the absolute value remains at minor 0.04 %. The final cost-benefit analysis adds value beyond a pure statistical approach: it provides objective statements that may justify evacuations. To deliver supportive information in a simple form, we propose a warning approach in terms of alarm levels. Our results do not justify evacuations prior to the M6.6 mainshock, but in certain districts afterwards. The ability to forecast the short-term seismic risk at any time-and with sufficient data anywhere-is the first step of personal decision-making and raising risk awareness among the public. Reference Van Stiphout, T., S. Wiemer, and W. Marzocchi (2010). 'Are short-term evacuations warranted? Case of the 2009 L'Aquila earthquake'. In: Geophysical Research Letters 37.6, pp. 1-5. url: http://onlinelibrary.wiley.com/doi/10.1029/ 2009GL042352/abstract.

Probabilistic Prediction of Lifetimes of Ceramic Parts

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Gyekenyesi, John P.; Jadaan, Osama M.; Palfi, Tamas; Powers, Lynn; Reh, Stefan; Baker, Eric H.

2006-01-01

ANSYS/CARES/PDS is a software system that combines the ANSYS Probabilistic Design System (PDS) software with a modified version of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) Version 6.0 software. [A prior version of CARES/Life was reported in Program for Evaluation of Reliability of Ceramic Parts (LEW-16018), NASA Tech Briefs, Vol. 20, No. 3 (March 1996), page 28.] CARES/Life models effects of stochastic strength, slow crack growth, and stress distribution on the overall reliability of a ceramic component. The essence of the enhancement in CARES/Life 6.0 is the capability to predict the probability of failure using results from transient finite-element analysis. ANSYS PDS models the effects of uncertainty in material properties, dimensions, and loading on the stress distribution and deformation. ANSYS/CARES/PDS accounts for the effects of probabilistic strength, probabilistic loads, probabilistic material properties, and probabilistic tolerances on the lifetime and reliability of the component. Even failure probability becomes a stochastic quantity that can be tracked as a response variable. ANSYS/CARES/PDS enables tracking of all stochastic quantities in the design space, thereby enabling more precise probabilistic prediction of lifetimes of ceramic components.

Cost‐Effectiveness of Clopidogrel‐Aspirin Versus Aspirin Alone for Acute Transient Ischemic Attack and Minor Stroke

PubMed Central

Pan, Yuesong; Wang, Anxin; Liu, Gaifen; Zhao, Xingquan; Meng, Xia; Zhao, Kun; Liu, Liping; Wang, Chunxue; Johnston, S. Claiborne; Wang, Yilong; Wang, Yongjun

2014-01-01

Background Treatment with the combination of clopidogrel and aspirin taken soon after a transient ischemic attack (TIA) or minor stroke was shown to reduce the 90‐day risk of stroke in a large trial in China, but the cost‐effectiveness is unknown. This study sought to estimate the cost‐effectiveness of the clopidogrel‐aspirin regimen for acute TIA or minor stroke. Methods and Results A Markov model was created to determine the cost‐effectiveness of treatment of acute TIA or minor stroke patients with clopidogrel‐aspirin compared with aspirin alone. Inputs for the model were obtained from clinical trial data, claims databases, and the published literature. The main outcome measure was cost per quality‐adjusted life‐years (QALYs) gained. One‐way and multivariable probabilistic sensitivity analyses were performed to test the robustness of the findings. Compared with aspirin alone, clopidogrel‐aspirin resulted in a lifetime gain of 0.037 QALYs at an additional cost of CNY 1250 (US$ 192), yielding an incremental cost‐effectiveness ratio of CNY 33 800 (US$ 5200) per QALY gained. Probabilistic sensitivity analysis showed that clopidogrel‐aspirin therapy was more cost‐effective in 95.7% of the simulations at a willingness‐to‐pay threshold recommended by the World Health Organization of CNY 105 000 (US$ 16 200) per QALY. Conclusions Early 90‐day clopidogrel‐aspirin regimen for acute TIA or minor stroke is highly cost‐effective in China. Although clopidogrel is generic, Plavix is brand in China. If Plavix were generic, treatment with clopidogrel‐aspirin would have been cost saving. PMID:24904018

Probabilistic structural analysis methods for improving Space Shuttle engine reliability

NASA Technical Reports Server (NTRS)

Boyce, L.

1989-01-01

Probabilistic structural analysis methods are particularly useful in the design and analysis of critical structural components and systems that operate in very severe and uncertain environments. These methods have recently found application in space propulsion systems to improve the structural reliability of Space Shuttle Main Engine (SSME) components. A computer program, NESSUS, based on a deterministic finite-element program and a method of probabilistic analysis (fast probability integration) provides probabilistic structural analysis for selected SSME components. While computationally efficient, it considers both correlated and nonnormal random variables as well as an implicit functional relationship between independent and dependent variables. The program is used to determine the response of a nickel-based superalloy SSME turbopump blade. Results include blade tip displacement statistics due to the variability in blade thickness, modulus of elasticity, Poisson's ratio or density. Modulus of elasticity significantly contributed to blade tip variability while Poisson's ratio did not. Thus, a rational method for choosing parameters to be modeled as random is provided.

A Bayesian model averaging approach with non-informative priors for cost-effectiveness analyses.

PubMed

Conigliani, Caterina

2010-07-20

We consider the problem of assessing new and existing technologies for their cost-effectiveness in the case where data on both costs and effects are available from a clinical trial, and we address it by means of the cost-effectiveness acceptability curve. The main difficulty in these analyses is that cost data usually exhibit highly skew and heavy-tailed distributions, so that it can be extremely difficult to produce realistic probabilistic models for the underlying population distribution. Here, in order to integrate the uncertainty about the model into the analysis of cost data and into cost-effectiveness analyses, we consider an approach based on Bayesian model averaging (BMA) in the particular case of weak prior informations about the unknown parameters of the different models involved in the procedure. The main consequence of this assumption is that the marginal densities required by BMA are undetermined. However, in accordance with the theory of partial Bayes factors and in particular of fractional Bayes factors, we suggest replacing each marginal density with a ratio of integrals that can be efficiently computed via path sampling. Copyright (c) 2010 John Wiley & Sons, Ltd.

Polycrystalline silicon study: Low-cost silicon refining technology prospects and semiconductor-grade polycrystalline silicon availability through 1988

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Ferber, R.; Lutwack, R.; Lorenz, J. H.; Pellin, R.

1984-01-01

Photovoltaic arrays that convert solar energy into electrical energy can become a cost effective bulk energy generation alternative, provided that an adequate supply of low cost materials is available. One of the key requirements for economic photovoltaic cells is reasonably priced silicon. At present, the photovoltaic industry is dependent upon polycrystalline silicon refined by the Siemens process primarily for integrated circuits, power devices, and discrete semiconductor devices. This dependency is expected to continue until the DOE sponsored low cost silicon refining technology developments have matured to the point where they are in commercial use. The photovoltaic industry can then develop its own source of supply. Silicon material availability and market pricing projections through 1988 are updated based on data collected early in 1984. The silicon refining industry plans to meet the increasing demands of the semiconductor device and photovoltaic product industries are overviewed. In addition, the DOE sponsored technology research for producing low cost polycrystalline silicon, probabilistic cost analysis for the two most promising production processes for achieving the DOE cost goals, and the impacts of the DOE photovoltaics program silicon refining research upon the commercial polycrystalline silicon refining industry are addressed.

Structural Probability Concepts Adapted to Electrical Engineering

NASA Technical Reports Server (NTRS)

Steinberg, Eric P.; Chamis, Christos C.

1994-01-01

Through the use of equivalent variable analogies, the authors demonstrate how an electrical subsystem can be modeled by an equivalent structural subsystem. This allows the electrical subsystem to be probabilistically analyzed by using available structural reliability computer codes such as NESSUS. With the ability to analyze the electrical subsystem probabilistically, we can evaluate the reliability of systems that include both structural and electrical subsystems. Common examples of such systems are a structural subsystem integrated with a health-monitoring subsystem, and smart structures. Since these systems have electrical subsystems that directly affect the operation of the overall system, probabilistically analyzing them could lead to improved reliability and reduced costs. The direct effect of the electrical subsystem on the structural subsystem is of secondary order and is not considered in the scope of this work.

Cost-effectiveness of cerebrospinal biomarkers for the diagnosis of Alzheimer's disease.

PubMed

Lee, Spencer A W; Sposato, Luciano A; Hachinski, Vladimir; Cipriano, Lauren E

2017-03-16

Accurate and timely diagnosis of Alzheimer's disease (AD) is important for prompt initiation of treatment in patients with AD and to avoid inappropriate treatment of patients with false-positive diagnoses. Using a Markov model, we estimated the lifetime costs and quality-adjusted life-years (QALYs) of cerebrospinal fluid biomarker analysis in a cohort of patients referred to a neurologist or memory clinic with suspected AD who remained without a definitive diagnosis of AD or another condition after neuroimaging. Parametric values were estimated from previous health economic models and the medical literature. Extensive deterministic and probabilistic sensitivity analyses were performed to evaluate the robustness of the results. At a 12.7% pretest probability of AD, biomarker analysis after normal neuroimaging findings has an incremental cost-effectiveness ratio (ICER) of $11,032 per QALY gained. Results were sensitive to the pretest prevalence of AD, and the ICER increased to over $50,000 per QALY when the prevalence of AD fell below 9%. Results were also sensitive to patient age (biomarkers are less cost-effective in older cohorts), treatment uptake and adherence, biomarker test characteristics, and the degree to which patients with suspected AD who do not have AD benefit from AD treatment when they are falsely diagnosed. The cost-effectiveness of biomarker analysis depends critically on the prevalence of AD in the tested population. In general practice, where the prevalence of AD after clinical assessment and normal neuroimaging findings may be low, biomarker analysis is unlikely to be cost-effective at a willingness-to-pay threshold of $50,000 per QALY gained. However, when at least 1 in 11 patients has AD after normal neuroimaging findings, biomarker analysis is likely cost-effective. Specifically, for patients referred to memory clinics with memory impairment who do not present neuroimaging evidence of medial temporal lobe atrophy, pretest prevalence of AD may exceed 15%. Biomarker analysis is a potentially cost-saving diagnostic method and should be considered for adoption in high-prevalence centers.

Cost-effectiveness of lung volume reduction coil treatment in patients with severe emphysema: results from the 2-year follow-up crossover REVOLENS study (REVOLENS-2 study).

PubMed

Bulsei, Julie; Leroy, Sylvie; Perotin, Jeanne-Marie; Mal, Hervé; Marquette, Charles-Hugo; Dutau, Hervé; Bourdin, Arnaud; Vergnon, Jean-Michel; Pison, Christophe; Kessler, Romain; Jounieaux, Vincent; Salaün, Mathieu; Marceau, Armelle; Dukic, Sylvain; Barbe, Coralie; Bonnaire, Margaux; Deslee, Gaëtan; Durand-Zaleski, Isabelle

2018-05-09

The REVOLENS study compared lung volume reduction coil treatment to usual care in patients with severe emphysema at 1 year, resulting in improved quality-adjusted life-year (QALY) and higher costs. Durability of the coil treatment benefit and its cost-effectiveness at 2 years are now assessed. After one year, the REVOLENS trial's usual care group patients received coil treatment (second-line coil treatment group). Costs and QALYs were assessed in both arms at 2 years and an incremental cost-effectiveness ratio in cost per QALY gained was calculated. The uncertainty of the results was estimated by probabilistic bootstrapping. The average cost of coil treatment in both groups was estimated at €24,356. The average total cost at 2 years was €9655 higher in the first-line coil treatment group (p = 0.07) and the difference in QALY between the two groups was 0.127 (p = 0.12) in favor of first-line coil treatment group. The 2-year incremental cost-effectiveness ratio (ICER) was €75,978 / QALY. The scatter plot of the probabilistic bootstrapping had 92% of the replications in the top right-hand quadrant. First-line coil treatment was more expensive but also more effective than second-line coil treatment at 2 years, with a 2-year ICER of €75,978 / QALY. ClinicalTrials.gov Identifier NCT01822795 .

Determining the cost-effectiveness of endoscopic surveillance for gastric cancer in patients with precancerous lesions.

PubMed

Wu, Jin Tong; Zhou, Jun; Naidoo, Nasheen; Yang, Wen Yu; Lin, Xiao Cheng; Wang, Pei; Ding, Jin Qin; Wu, Chen Bin; Zhou, Hui Jun

2016-12-01

To identify the optimal strategy for gastric cancer (GC) prevention by evaluating the cost-effectiveness of esophagogastroduodenoscopy (EGD)-based preventive strategies. We conducted a model-based cost-effectiveness analysis. Adopting a healthcare payer's perspective, Markov models simulated the clinical experience of the target population (Singaporean Chinese 50-69 years old) undergoing endoscopic screening, endoscopic surveillance and usual care of do-nothing. The screening strategy examined the cohort every alternate year whereas the surveillance strategy provided annual EGD only to people with precancerous lesions. For each strategy, discounted lifetime costs ($) and quality adjusted life years (QALY) were estimated and compared to generate incremental cost-effectiveness ratio (ICER). Deterministic and probabilistic sensitivity analysis was conducted to identify influential parameters and quantify the impact of model uncertainties. Annual EGD surveillance with an ICER of $34 200/QALY was deemed cost-effective for GC prevention within the Singapore healthcare system. To inform implementation, the models identified six influential factors and their respective thresholds, namely discount rate (<4.20%), age of starting surveillance (>51.6 years), proportion of program cost in delivering endoscopy (<65%), cost of follow-up EGD (<$484), utility of stage 1 GC patients (>0.72) and odds ratio of GC for high-risk subjects (>3.93). The likelihood that surveillance is the most cost-effective strategy is 69.5% accounting for model uncertainties. Endoscopic surveillance of gastric premalignancies can be a cost-effective strategy for GC prevention. Its implementation requires careful assessment on factors influencing the actual cost-effectiveness. © 2016 John Wiley & Sons Australia, Ltd.

Preoperative paravertebral blocks for the management of acute pain following mastectomy: a cost-effectiveness analysis.

PubMed

Offodile, Anaeze C; Sheckter, Clifford C; Tucker, Austin; Watzker, Anna; Ottino, Kevin; Zammert, Martin; Padula, William V

2017-10-01

Preoperative paravertebral blocks (PPVBs) are routinely used for treating post-mastectomy pain, yet uncertainties remain about the cost-effectiveness of this modality. We aim to evaluate the cost-effectiveness of PPVBs at common willingness-to-pay (WTP) thresholds. A decision analytic model compared two strategies: general anesthesia (GA) alone versus GA with multilevel PPVB. For the GA plus PPVB limb, patients were subjected to successful block placement versus varying severity of complications based on literature-derived probabilities. The need for rescue pain medication was the terminal node for all postoperative scenarios. Patient-reported pain scores sourced from published meta-analyses measured treatment effectiveness. Costing was derived from wholesale acquisition costs, the Medicare fee schedule, and publicly available hospital charge masters. Charges were converted to costs and adjusted for 2016 US dollars. A commercial payer perspective was adopted. Incremental cost-effectiveness ratios (ICERs) were evaluated against WTP thresholds of $500 and $50,000 for postoperative pain control. The ICER for preoperative paravertebral blocks was $154.49 per point reduction in pain score. 15% variation in inpatient costs resulted in ICER values ranging from $124.40-$180.66 per pain point score reduction. Altering the probability of block success by 5% generated ICER values of $144.71-$163.81 per pain score reduction. Probabilistic sensitivity analysis yielded cost-effective trials 69.43% of the time at $500 WTP thresholds. Over a broad range of probabilities, PPVB in mastectomy reduces postoperative pain at an acceptable incremental cost compared to GA. Commercial payers should be persuaded to reimburse this technique based on convincing evidence of cost-effectiveness.

The costs and benefits of enhanced depression care to employers.

PubMed

Wang, Philip S; Patrick, Amanda; Avorn, Jerry; Azocar, Francisca; Ludman, Evette; McCulloch, Joyce; Simon, Gregory; Kessler, Ronald

2006-12-01

Although outreach and enhanced treatment interventions improve depression outcomes, uptake has been poor in part because purchasers lack information on their return on investment. To estimate the costs and benefits of enhanced depression care for workers from the societal and employer-purchaser perspectives. Cost-effectiveness and cost-benefit analyses using state-transition Markov models. Simulated movements between health states were based on probabilities drawn from the clinical literature. Hypothetical cohort of 40-year-old workers. Intervention Enhanced depression care consisting of a depression screen and care management for those depressed vs usual care. Our base-case cost-effectiveness analysis was from the societal perspective; costs and quality-adjusted life-years were used to compute the incremental cost-effectiveness of the intervention relative to usual care. A secondary cost-benefit analysis from the employer's perspective tracked monetary costs and monetary benefits accruing to employers during a 5-year time horizon. From the societal perspective, screening and depression care management for workers result in an incremental cost-effectiveness ratio of $19 976 per quality-adjusted life-year relative to usual care. These results are consistent with recent primary care effectiveness trials and within the range for medical interventions usually covered by employer-sponsored insurance. From the employer's perspective, enhanced depression care yields a net cumulative benefit of $2895 after 5 years. In 1-way and probabilistic sensitivity analyses, these findings were robust to a variety of assumptions. If these results can be replicated in effectiveness trials directly assessing effects on work outcomes, they suggest that enhanced treatment quality programs for depression are cost-beneficial to purchasers.

Economic Analysis of First-Line Treatment with Erlotinib in an EGFR-Mutated Population with Advanced NSCLC.

PubMed

Vergnenegre, Alain; Massuti, Bartomeu; de Marinis, Filippo; Carcereny, Enric; Felip, Enriqueta; Do, Pascal; Sanchez, Jose Miguel; Paz-Arez, Luis; Chouaid, Christos; Rosell, Rafael

2016-06-01

The cost-effectiveness of first-line tyrosine kinase inhibitor therapy in epidermal growth factor receptor gene (EGFR)-mutated advanced-stage non-small cell lung cancer (NSCLC) is poorly documented. We therefore conducted a cost-effectiveness analysis of first-line treatment with erlotinib versus standard chemotherapy in European patients with advanced-stage EGFR-mutated NSCLC who were enrolled in the European Erlotinib versus Chemotherapy trial. The European Erlotinib versus Chemotherapy study was a multicenter, open-label, randomized phase III trial performed mainly in Spain, France, and Italy. We based our economic analysis on clinical data and data on resource consumption (drugs, drug administration, adverse events, and second-line treatments) collected during this trial. Utility values were derived from the literature. Incremental cost-effectiveness ratios were calculated for the first-line treatment phase and for the overall strategy from the perspective of the three participating countries. Sensitivity analyses were performed by selecting the main cost drivers. Compared with standard first-line chemotherapy, the first-line treatment with erlotinib was cost saving (€7807, €17,311, and €19,364 for Spain, Italy and France, respectively) and yielded a gain of 0.117 quality-adjusted life-years. A probabilistic sensitivity analysis indicated that, given a willingness to pay at least €90,000 for 1 quality-adjusted life-year, the probability that a strategy of first-line erlotinib would be cost-effective was 100% in France, 100% in Italy, and 99.8% in Spain. This economic analysis shows that first-line treatment with erlotinib, versus standard chemotherapy, is a dominant strategy for EGFR-mutated advanced-stage NSCLC in three European countries. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

System Level Uncertainty Assessment for Collaborative RLV Design

NASA Technical Reports Server (NTRS)

Charania, A. C.; Bradford, John E.; Olds, John R.; Graham, Matthew

2002-01-01

A collaborative design process utilizing Probabilistic Data Assessment (PDA) is showcased. Given the limitation of financial resources by both the government and industry, strategic decision makers need more than just traditional point designs, they need to be aware of the likelihood of these future designs to meet their objectives. This uncertainty, an ever-present character in the design process, can be embraced through a probabilistic design environment. A conceptual design process is presented that encapsulates the major engineering disciplines for a Third Generation Reusable Launch Vehicle (RLV). Toolsets consist of aerospace industry standard tools in disciplines such as trajectory, propulsion, mass properties, cost, operations, safety, and economics. Variations of the design process are presented that use different fidelities of tools. The disciplinary engineering models are used in a collaborative engineering framework utilizing Phoenix Integration's ModelCenter and AnalysisServer environment. These tools allow the designer to join disparate models and simulations together in a unified environment wherein each discipline can interact with any other discipline. The design process also uses probabilistic methods to generate the system level output metrics of interest for a RLV conceptual design. The specific system being examined is the Advanced Concept Rocket Engine 92 (ACRE-92) RLV. Previous experience and knowledge (in terms of input uncertainty distributions from experts and modeling and simulation codes) can be coupled with Monte Carlo processes to best predict the chances of program success.

Cost-effectiveness of sacubitril/valsartan in the treatment of heart failure with reduced ejection fraction

PubMed Central

McMurray, John J V; Trueman, David; Hancock, Elizabeth; Cowie, Martin R; Briggs, Andrew; Taylor, Matthew; Mumby-Croft, Juliet; Woodcock, Fionn; Lacey, Michael; Haroun, Rola; Deschaseaux, Celine

2018-01-01

Objective Chronic heart failure with reduced ejection fraction (HF-REF) represents a major public health issue and is associated with considerable morbidity and mortality. We evaluated the cost-effectiveness of sacubitril/valsartan (formerly LCZ696) compared with an ACE inhibitor (ACEI) (enalapril) in the treatment of HF-REF from the perspective of healthcare providers in the UK, Denmark and Colombia. Methods A cost-utility analysis was performed based on data from a multinational, Phase III randomised controlled trial. A decision-analytic model was developed based on a series of regression models, which extrapolated health-related quality of life, hospitalisation rates and survival over a lifetime horizon. The primary outcome was the incremental cost-effectiveness ratio (ICER). Results In the UK, the cost per quality-adjusted life-year (QALY) gained for sacubitril/valsartan (using cardiovascular mortality) was £17 100 (€20 400) versus enalapril. In Denmark, the ICER for sacubitril/valsartan was Kr 174 000 (€22 600). In Colombia, the ICER was COP$39.5 million (€11 200) per QALY gained. Deterministic sensitivity analysis showed that results were most sensitive to the extrapolation of mortality, duration of treatment effect and time horizon, but were robust to other structural changes, with most scenarios associated with ICERs below the willingness-to-pay threshold for all three country settings. Probabilistic sensitivity analysis suggested the probability that sacubitril/valsartan was cost-effective at conventional willingness-to-pay thresholds was 68%–94% in the UK, 84% in Denmark and 95% in Colombia. Conclusions Our analysis suggests that, in all three countries, sacubitril/valsartan is likely to be cost-effective compared with an ACEI (the current standard of care) in patients with HF-REF. PMID:29269379

Cost-Effectiveness Analysis of Alternative Antiviral Strategies for the Treatment of HBeAg-Positive and HBeAg-Negative Chronic Hepatitis B in the United Kingdom.

PubMed

Bermingham, Sarah L; Hughes, Ralph; Fenu, Elisabetta; Sawyer, Laura M; Boxall, Elizabeth; T Kennedy, Patrick; Dusheiko, Geoff; Hill-Cawthorne, Grant; Thomas, Howard

2015-09-01

Seven drugs are licensed for the treatment of chronic hepatitis B (CHB) in the United Kingdom. Which initial treatment, secondary therapy, and whether antivirals should be given alone or in combination are questions of considerable uncertainty. The aim of this model was to undertake a comprehensive economic evaluation of all antiviral treatments for CHB to recommend the most cost-effective therapeutic sequence. We developed a probabilistic Markov model to compare the cost-effectiveness of all clinically relevant antiviral treatment sequences for nucleos(t)ide-naive adults with hepatitis B e-antigen (HBeAg)-positive or HBeAg-negative CHB. Relative rates of HBeAg seroconversion and viral suppression were obtained from a network meta-analysis. Data on mortality, antiviral drug resistance, durability of response, adverse events, and costs were obtained from published literature. Results are reported in terms of lifetime costs, quality-adjusted life-years (QALYs), and expected net benefit. In the base-case analysis, pegylated interferon alpha-2a (peg-IFN α-2a) followed by tenofovir disoproxil fumarate was most effective and cost-effective in HBeAg-positive patients, with a cost of £7488 per QALY gained compared with no treatment. In HBeAg-negative patients, peg-IFN α-2a followed by entecavir was most effective and cost-effective, with a cost of £6981 per QALY gained. The model was robust to a wide range of sensitivity analyses. Peg-IFN α-2a followed by tenofovir disoproxil fumarate or entecavir is the most effective antiviral treatment strategy for people with both variants of CHB. At a cost of less than £10,000 per QALY gained, these sequences are considered cost-effective in England and Wales. The results of this analysis were used to inform 2013 National Institute for Health and Care Excellence guideline recommendations. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Oseltamivir Treatment for Children with Influenza-Like Illness in China: A Cost-Effectiveness Analysis.

PubMed

Shen, Kunling; Xiong, Tengbin; Tan, Seng Chuen; Wu, Jiuhong

2016-01-01

Influenza is a common viral respiratory infection that causes epidemics and pandemics in the human population. Oseltamivir is a neuraminidase inhibitor-a new class of antiviral therapy for influenza. Although its efficacy and safety have been established, there is uncertainty regarding whether influenza-like illness (ILI) in children is best managed by oseltamivir at the onset of illness, and its cost-effectiveness in children has not been studied in China. To evaluate the cost-effectiveness of post rapid influenza diagnostic test (RIDT) treatment with oseltamivir and empiric treatment with oseltamivir comparing with no antiviral therapy against influenza for children with ILI. We developed a decision-analytic model based on previously published evidence to simulate and evaluate 1-year potential clinical and economic outcomes associated with three managing strategies for children presenting with symptoms of influenza. Model inputs were derived from literature and expert opinion of clinical practice and research in China. Outcome measures included costs and quality-adjusted life year (QALY). All the interventions were compared with incremental cost-effectiveness ratios (ICER). In base case analysis, empiric treatment with oseltamivir consistently produced the greatest gains in QALY. When compared with no antiviral therapy, the empiric treatment with oseltamivir strategy is very cost effective with an ICER of RMB 4,438. When compared with the post RIDT treatment with oseltamivir, the empiric treatment with oseltamivir strategy is dominant. Probabilistic sensitivity analysis projected that there is a 100% probability that empiric oseltamivir treatment would be considered as a very cost-effective strategy compared to the no antiviral therapy, according to the WHO recommendations for cost-effectiveness thresholds. The same was concluded with 99% probability for empiric oseltamivir treatment being a very cost-effective strategy compared to the post RIDT treatment with oseltamivir. In the Chinese setting of current health system, our modelling based simulation analysis suggests that empiric treatment with oseltamivir to be a cost-saving and very cost-effective strategy in managing children with ILI.

Cost-Effectiveness of Haemorrhoidal Artery Ligation versus Rubber Band Ligation for the Treatment of Grade II-III Haemorrhoids: Analysis Using Evidence from the HubBLe Trial.

PubMed

Alshreef, Abualbishr; Wailoo, Allan J; Brown, Steven R; Tiernan, James P; Watson, Angus J M; Biggs, Katie; Bradburn, Mike; Hind, Daniel

2017-09-01

Haemorrhoids are a common condition, with nearly 30,000 procedures carried out in England in 2014/15, and result in a significant quality-of-life burden to patients and a financial burden to the healthcare system. This study examined the cost effectiveness of haemorrhoidal artery ligation (HAL) compared with rubber band ligation (RBL) in the treatment of grade II-III haemorrhoids. This analyses used data from the HubBLe study, a multicentre, open-label, parallel group, randomised controlled trial conducted in 17 acute UK hospitals between September 2012 and August 2015. A full economic evaluation, including long-term cost effectiveness, was conducted from the UK National Health Service (NHS) perspective. Main outcomes included healthcare costs, quality-adjusted life-years (QALYs) and recurrence. Cost-effectiveness results were presented in terms of incremental cost per QALY gained and cost per recurrence avoided. Extrapolation analysis for 3 years beyond the trial follow-up, two subgroup analyses (by grade of haemorrhoids and recurrence following RBL at baseline), and various sensitivity analyses were undertaken. In the primary base-case within-trial analysis, the incremental total mean cost per patient for HAL compared with RBL was £1027 (95% confidence interval [CI] £782-£1272, p < 0.001). The incremental QALYs were 0.01 QALYs (95% CI -0.02 to 0.04, p = 0.49). This generated an incremental cost-effectiveness ratio (ICER) of £104,427 per QALY. In the extrapolation analysis, the estimated probabilistic ICER was £21,798 per QALY. Results from all subgroup and sensitivity analyses did not materially change the base-case result. Under all assessed scenarios, the HAL procedure was not cost effective compared with RBL for the treatment of grade II-III haemorrhoids at a cost-effectiveness threshold of £20,000 per QALY; therefore, economically, its use in the NHS should be questioned.

The cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains.

PubMed

Fatoye, Francis; Haigh, Carol

2016-05-01

To examine the cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains. Economic evaluation based on cost-utility analysis. Ankle sprains are a source of morbidity and absenteeism from work, accounting for 15-20% of all sports injuries. Semi-rigid ankle brace and taping are functional treatment interventions used by Musculoskeletal Physiotherapists and Nurses to facilitate return to work following acute ankle sprains. A decision model analysis, based on cost-utility analysis from the perspective of National Health Service was used. The primary outcomes measure was incremental cost-effectiveness ratio, based on quality-adjusted life years. Costs and quality of life data were derived from published literature, while model clinical probabilities were sourced from Musculoskeletal Physiotherapists. The cost and quality adjusted life years gained using semi-rigid ankle brace was £184 and 0.72 respectively. However, the cost and quality adjusted life years gained following taping was £155 and 0.61 respectively. The incremental cost-effectiveness ratio for the semi-rigid brace was £263 per quality adjusted life year. Probabilistic sensitivity analysis showed that ankle brace provided the highest net-benefit, hence the preferred option. Taping is a cheaper intervention compared with ankle brace to facilitate return to work following first-time ankle sprains. However, the incremental cost-effectiveness ratio observed for ankle brace was less than the National Institute for Health and Care Excellence threshold and the intervention had a higher net-benefit, suggesting that it is a cost-effective intervention. Decision-makers may be willing to pay £263 for an additional gain in quality adjusted life year. The findings of this economic evaluation provide justification for the use of semi-rigid ankle brace by Musculoskeletal Physiotherapists and Nurses to facilitate return to work in individuals with first-time ankle sprains. © 2016 John Wiley & Sons Ltd.

Cost-effectiveness and budget impact analysis of a population-based screening program for colorectal cancer.

PubMed

Pil, L; Fobelets, M; Putman, K; Trybou, J; Annemans, L

2016-07-01

Colorectal cancer (CRC) is one of the leading causes of cancer mortality in Belgium. In Flanders (Belgium), a population-based screening program with a biennial immunochemical faecal occult blood test (iFOBT) in women and men aged 56-74 has been organised since 2013. This study assessed the cost-effectiveness and budget impact of the colorectal population-based screening program in Flanders (Belgium). A health economic model was conducted, consisting of a decision tree simulating the screening process and a Markov model, with a time horizon of 20years, simulating natural progression. Predicted mortality and incidence, total costs, and quality-adjusted life-years (QALYs) with and without the screening program were calculated in order to determine the incremental cost-effectiveness ratio of CRC screening. Deterministic and probabilistic sensitivity analyses were conducted, taking into account uncertainty of the model parameters. Mortality and incidence were predicted to decrease over 20years. The colorectal screening program in Flanders is found to be cost-effective with an ICER of 1681/QALY (95% CI -1317 to 6601) in males and €4,484/QALY (95% CI -3254 to 18,163). The probability of being cost-effective given a threshold of €35,000/QALY was 100% and 97.3%, respectively. The budget impact analysis showed the extra cost for the health care payer to be limited. This health economic analysis has shown that despite the possible adverse effects of screening and the extra costs for the health care payer and the patient, the population-based screening program for CRC in Flanders is cost-effective and should therefore be maintained. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Cost-Utility Analysis of Extending Public Health Insurance Coverage to Include Diabetic Retinopathy Screening by Optometrists.

PubMed

van Katwyk, Sasha; Jin, Ya-Ping; Trope, Graham E; Buys, Yvonne; Masucci, Lisa; Wedge, Richard; Flanagan, John; Brent, Michael H; El-Defrawy, Sherif; Tu, Hong Anh; Thavorn, Kednapa

2017-09-01

Diabetic retinopathy (DR) is one of the leading causes of vision loss and blindness in Canada. Eye examinations play an important role in early detection. However, DR screening by optometrists is not always universally covered by public or private health insurance plans. This study assessed whether expanding public health coverage to include diabetic eye examinations for retinopathy by optometrists is cost-effective from the perspective of the health care system. We conducted a cost-utility analysis of extended coverage for diabetic eye examinations in Prince Edward Island to include examinations by optometrists, not currently publicly covered. We used a Markov chain to simulate disease burden based on eye examination rates and DR progression over a 30-year time horizon. Results were presented as an incremental cost per quality-adjusted life year (QALY) gained. A series of one-way and probabilistic sensitivity analyses were performed. Extending public health coverage to eye examinations by optometrists was associated with higher costs ($9,908,543.32) and improved QALYs (156,862.44), over 30 years, resulting in an incremental cost-effectiveness ratio of $1668.43/QALY gained. Sensitivity analysis showed that the most influential determinants of the results were the cost of optometric screening and selected utility scores. At the commonly used threshold of $50,000/QALY, the probability that the new policy was cost-effective was 99.99%. Extending public health coverage to eye examinations by optometrists is cost-effective based on a commonly used threshold of $50,000/QALY. Findings from this study can inform the decision to expand public-insured optometric services for patients with diabetes. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Allocating provider resources to diagnose and treat restless legs syndrome: a cost-utility analysis.

PubMed

Padula, William V; Phelps, Charles E; Moran, Dane; Earley, Christopher

2017-10-01

Restless legs syndrome (RLS) is a neurological disorder that is frequently misdiagnosed, resulting in delays in proper treatment. The objective of this study was to analyze the cost-utility of training primary care providers (PCP) in early and accurate diagnosis of RLS. We used a Markov model to compare two strategies: one where PCPs received training to diagnose RLS (informed care) and one where PCPs did not receive training (standard care). This analysis was conducted from the US societal and health sector perspectives over one-year, five-year, and lifetime (50-year) horizons. Costs were adjusted to 2016 USD, utilities measured as quality-adjusted life-years (QALYs), and both measures were discounted annually at 3%. Cost, utilities, and probabilities for the model were obtained through a comprehensive review of literature. An incremental cost-effectiveness ratio (ICER) was calculated to interpret our findings at a willingness-to-pay threshold of $100,000/QALY. Univariate and multivariate analyses were conducted to test model uncertainty, in addition to calculating the expected value of perfect information. Providing training to PCPs to correctly diagnose RLS was cost-effective since it cost $2021 more and gained 0.44 QALYs per patient over the course of a lifetime, resulting in an ICER of $4593/QALY. The model was sensitive to the utility for treated and untreated RLS. The probabilistic sensitivity analysis revealed that at $100,000/QALY, informed care had a 65.5% probability of being cost-effective. A program to train PCPs to better diagnose RLS appears to be a cost-effective strategy for improving outcomes for RLS patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Economic evaluation of varicella vaccination in Spain: results from a dynamic model.

PubMed

Lenne, X; Diez Domingo, J; Gil, A; Ridao, M; Lluch, J A; Dervaux, B

2006-11-17

Varicella is a universal childhood disease in Spain, causing approximately 400,000 cases, 1,500 hospitalizations and 15 deaths every year. The aim of this study is to determine the economic impact of childhood varicella vaccination on the burden of disease and associated costs by using a dynamic model. The analysis is based on the varicella transmission model developed by Halloran and adapted to the Spanish context. Cost data (Euro, 2004) were derived from previous studies and official tariffs. Two vaccination scenarios were analysed: (1) routine vaccination program for children aged 1-2 years, and (2) routine vaccination program for children aged 1-2 years completed by a catch-up program during the first year of vaccine marketing for children aged 2-11 years. The analysis considers that a similar coverage rate to the MMR one would be achieved (97.15%). A societal perspective, including direct and indirect costs, and a health care payor perspective were adopted. A probabilistic sensitivity analysis was performed. A routine vaccination program has a positive impact on varicella-related morbidity: the number of varicella cases is estimated to be reduced by 89%, and 1230 hospitalizations are prevented. From the societal perspective, scenario (1) is cost-saving whether or not indirect costs are considered (-51 and -4%, respectively). From the Health Care System the strategy is cost-effective, with a cost-effectiveness ratio estimated at 3,982 Euro per life-year gained, although it leads to a small increase in the costs. Considering the impact of vaccination on morbidity and costs, a routine childhood vaccination program against varicella is worth while in Spain without taking into account the potential impact on HZ.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 2: Literature surveys of critical Space Shuttle main engine components

NASA Technical Reports Server (NTRS)

Rajagopal, K. R.

1992-01-01

The technical effort and computer code development is summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis. Volume 2 is a summary of critical SSME components.

Cost-effectiveness analysis of different types of labor for singleton pregnancy: real life data.

PubMed

Lakić, Dragana; Petrović, Branko; Petrova, Guenka

2014-01-01

Views on the conduct of labor have changed over time, and a significant difference exists in relation to obstetric centers. To assess cost, clinical outcomes and cost-effectiveness of different types of labor in singleton pregnancies. A decision model was used to compare vaginal labor, induced labor and planned cesarean section. All data were taken from the Book of Labor from the University Hospital for Gynecology and Obstetrics "Narodni Front", Belgrade, Serbia for labors conducted during one month period in 2011. Successful delivery (i.e. labor that began up to 42 gestation weeks, without maternal mortality and the newborn Apgar scores greater than or equal to seven in the fifth minute of life) was considered as the outcome of the cost effectiveness-analysis. To test the robustness of this definition probabilistic sensitivity analysis was performed. From a total of 667 births, vaginal labor was conducted in 98 cases, induced vaginal in 442, while planned cesarean section was performed 127 times. Emergency cesarean section as a complication was much higher in the vaginal labor cohort compared to the induced vaginal cohort (OR=17.374; 95% CI: 8.522 to 35.418; p<0.001). The least costly type of labor was induced vaginal labor: average cost 461 euro, with an effectiveness of 98.17%. Both, vaginal and planned cesarean labor were dominated by the induced labor. The results were robust. Elective induction of labor was associated with the lowest cost compared to other types of labor, with favorable maternal and neonatal outcomes.

Probabilistic reasoning in data analysis.

PubMed

Sirovich, Lawrence

2011-09-20

This Teaching Resource provides lecture notes, slides, and a student assignment for a lecture on probabilistic reasoning in the analysis of biological data. General probabilistic frameworks are introduced, and a number of standard probability distributions are described using simple intuitive ideas. Particular attention is focused on random arrivals that are independent of prior history (Markovian events), with an emphasis on waiting times, Poisson processes, and Poisson probability distributions. The use of these various probability distributions is applied to biomedical problems, including several classic experimental studies.

Comparison of numerical weather prediction based deterministic and probabilistic wind resource assessment methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jie; Draxl, Caroline; Hopson, Thomas

Numerical weather prediction (NWP) models have been widely used for wind resource assessment. Model runs with higher spatial resolution are generally more accurate, yet extremely computational expensive. An alternative approach is to use data generated by a low resolution NWP model, in conjunction with statistical methods. In order to analyze the accuracy and computational efficiency of different types of NWP-based wind resource assessment methods, this paper performs a comparison of three deterministic and probabilistic NWP-based wind resource assessment methodologies: (i) a coarse resolution (0.5 degrees x 0.67 degrees) global reanalysis data set, the Modern-Era Retrospective Analysis for Research and Applicationsmore » (MERRA); (ii) an analog ensemble methodology based on the MERRA, which provides both deterministic and probabilistic predictions; and (iii) a fine resolution (2-km) NWP data set, the Wind Integration National Dataset (WIND) Toolkit, based on the Weather Research and Forecasting model. Results show that: (i) as expected, the analog ensemble and WIND Toolkit perform significantly better than MERRA confirming their ability to downscale coarse estimates; (ii) the analog ensemble provides the best estimate of the multi-year wind distribution at seven of the nine sites, while the WIND Toolkit is the best at one site; (iii) the WIND Toolkit is more accurate in estimating the distribution of hourly wind speed differences, which characterizes the wind variability, at five of the available sites, with the analog ensemble being best at the remaining four locations; and (iv) the analog ensemble computational cost is negligible, whereas the WIND Toolkit requires large computational resources. Future efforts could focus on the combination of the analog ensemble with intermediate resolution (e.g., 10-15 km) NWP estimates, to considerably reduce the computational burden, while providing accurate deterministic estimates and reliable probabilistic assessments.« less

Cost-effectiveness analysis of quadrivalent influenza vaccination in at-risk adults and the elderly: an updated analysis in the U.K.

PubMed

Meier, G; Gregg, M; Poulsen Nautrup, B

2015-01-01

To update an earlier evaluation estimating the cost-effectiveness of quadrivalent influenza vaccination (QIV) compared with trivalent influenza vaccination (TIV) in the adult population currently recommended for influenza vaccination in the UK (all people aged ≥65 years and people aged 18-64 years with clinical risk conditions). This analysis takes into account updated vaccine prices, reference costs, influenza strain circulation, and burden of illness data. A lifetime, multi-cohort, static Markov model was constructed with seven age groups. The model was run in 1-year cycles for a lifetime, i.e., until the youngest patients at entry reached the age of 100 years. The base-case analysis was from the perspective of the UK National Health Service, with a secondary analysis from the societal perspective. Costs and benefits were discounted at 3.5%. Herd effects were not included. Inputs were derived from systematic reviews, peer-reviewed articles, and government publications and databases. One-way and probabilistic sensitivity analyses were performed. In the base-case, QIV would be expected to avoid 1,413,392 influenza cases, 41,780 hospitalizations, and 19,906 deaths over the lifetime horizon, compared with TIV. The estimated incremental cost-effectiveness ratio (ICER) was £14,645 per quality-adjusted life-year (QALY) gained. From the societal perspective, the estimated ICER was £13,497/QALY. A strategy of vaccinating only people aged ≥65 years had an estimated ICER of £11,998/QALY. Sensitivity analysis indicated that only two parameters, seasonal variation in influenza B matching and influenza A circulation, had a substantial effect on the ICER. QIV would be likely to be cost-effective compared with TIV in 68% of simulations with a willingness-to-pay threshold of <£20,000/QALY and 87% with a willingness-to-pay threshold of <£30,000/QALY. In this updated analysis, QIV was estimated to be cost-effective compared with TIV in the U.K.

Using discrete choice experiments within a cost-benefit analysis framework: some considerations.

PubMed

McIntosh, Emma

2006-01-01

A great advantage of the stated preference discrete choice experiment (SPDCE) approach to economic evaluation methodology is its immense flexibility within applied cost-benefit analyses (CBAs). However, while the use of SPDCEs in healthcare has increased markedly in recent years there has been a distinct lack of equivalent CBAs in healthcare using such SPDCE-derived valuations. This article outlines specific issues and some practical suggestions for consideration relevant to the development of CBAs using SPDCE-derived benefits. The article shows that SPDCE-derived CBA can adopt recent developments in cost-effectiveness methodology including the cost-effectiveness plane, appropriate consideration of uncertainty, the net-benefit framework and probabilistic sensitivity analysis methods, while maintaining the theoretical advantage of the SPDCE approach. The concept of a cost-benefit plane is no different in principle to the cost-effectiveness plane and can be a useful tool for reporting and presenting the results of CBAs.However, there are many challenging issues to address for the advancement of CBA methodology using SPCDEs within healthcare. Particular areas for development include the importance of accounting for uncertainty in SPDCE-derived willingness-to-pay values, the methodology of SPDCEs in clinical trial settings and economic models, measurement issues pertinent to using SPDCEs specifically in healthcare, and the importance of issues such as consideration of the dynamic nature of healthcare and the resulting impact this has on the validity of attribute definitions and context.

Improved Methodology for Developing Cost Uncertainty Models for Naval Vessels

DTIC Science & Technology

2009-04-22

Deegan , 2007). Risk cannot be assessed with a point estimate, as it represents a single value that serves as a best guess for the parameter to be...or stakeholders ( Deegan & Fields, 2007). This paper analyzes the current NAVSEA 05C Cruiser (CG(X)) probabilistic cost model including data...provided by Mr. Chris Deegan and his CG(X) analysts. The CG(X) model encompasses all factors considered for cost of the entire program, including

Comparative cost-benefit analysis of tele-homecare for community-dwelling elderly in Japan: Non-Government versus Government Supported Funding Models.

PubMed

Akiyama, Miki; Abraham, Chon

2017-08-01

Tele-homecare is gaining prominence as a viable care alternative, as evidenced by the increase in financial support from international governments to fund initiatives in their respective countries. The primary reason for the funding is to support efforts to reduce lags and increase capacity in access to care as well as to promote preventive measures that can avert costly emergent issues from arising. These efforts are especially important to super-aged and aging societies such as in Japan, many European countries, and the United States (US). However, to date and to our knowledge, a direct comparison of non-government vs. government-supported funding models for tele-homecare is particularly lacking in Japan. The aim of this study is to compare these operational models (i.e., non-government vs. government-supported funding) from a cost-benefit perspective. This simulation study applies to a Japanese hypothetical cohort with implications for other super-aged and aging societies abroad. We performed a cost-benefit analysis (CBA) on two operational models for enabling tele-homecare for elderly community-dwelling cohorts based on a decision tree model, which we created with parameters from published literature. The two models examined are (a) Model 1-non-government-supported funding that includes monthly fixed charges paid by users for a portion of the operating costs, and (b) Model 2-government-supported funding that includes startup and installation costs only (i.e., no operating costs) and no monthly user charges. We performed base case cost-benefit analysis and probabilistic cost-benefit analysis with a Monte Carlo simulation. We calculated net benefit and benefit-to-cost ratios (BCRs) from the societal perspective with a five-year time horizon applying a 3% discount rate for both cost and benefit values. The cost of tele-homecare included (a) the startup system expense, averaged over a five-year depreciation period, and (b) operation expenses (i.e., labor and non-labor) per user per year. The benefit of tele-homecare was measured by annual willingness to pay (WTP) for tele-homecare by a user and medical expenditures avoided. Both costs and benefits were inflated using the relevant Japanese consumer price index (CPI) and converted into 2015 US dollars with purchasing power parity (PPP) adjusted. Base case net benefits of Model 1 and Model 2 were $417.00 and $97.30, respectively. Base case BCR of Model 1 tele-homecare was 1.63, while Model 2 was 1.03. The probabilistic analysis estimated mean (95%CI) for BCRs of Model 1 and Model 2 was 1.84 (1.89, 1.88) and 1.46 (1.43, 1.49), respectively. Sensitivity analysis showed robustness of Model 1 in 7 parameters but Model 2 was sensitive in all key parameters such as initial system cost, device cost, number of users, and medical expenditure saved. Break-even analysis showed that the system cost of Model 2 had to be under $187,500. Our results for each model collectively showed that tele-homecare in Japan is cost-saving to some extent. However, the government-funded model (i.e., Model 2), which typically requires use of all startup funding to be spent within the first year on system costs, was inferior to the monthly fee model (i.e., Model 1) that did not use the government funding for installation or continued operations, but rather incorporated a monthly fee from users to support the receipt of services via tele-homecare. While the benefits of Model 1 outweighed the benefits of Model 2, the government-subsidized method employed in Model 2 could be more beneficial in general if some explicit prequalifying estimated metrics are instituted prior to funding. Thus, governments need to require applicants requesting funding to note, at a minimum, (a) estimated costs, (b) the expected number of tele-homecare users, and expected benefits such as (c) WTP by the user, or (d) medical expenditure saved by tele-homecare as a means of financing some of the operational costs. Copyright © 2017 Elsevier B.V. All rights reserved.

A cost-effectiveness analysis of propofol versus midazolam for procedural sedation in the emergency department.

PubMed

Hohl, Corinne Michèle; Nosyk, Bohdan; Sadatsafavi, Mohsen; Anis, Aslam Hayat

2008-01-01

To determine the incremental cost-effectiveness of using propofol versus midazolam for procedural sedation (PS) in adults in the emergency department (ED). The authors conducted a cost-effectiveness analysis from the perspective of the health care provider. The primary outcome was the incremental cost (or savings) to achieve one additional successful sedation with propofol compared to midazolam. A decision model was developed in which the clinical effectiveness and cost of a PS strategy using either agent was estimated. The authors derived estimates of clinical effectiveness and risk of adverse events (AEs) from a systematic review. The cost of each clinical outcome was determined by incorporating the baseline cost of the ED visit, the cost of the drug, the cost of labor of physicians and nurses, the cost and probability of an AE, and the cost and probability of a PS failure. A standard meta-analytic technique was used to calculate the weighted mean difference in recovery times and obtain mean drug doses from patient-level data from a randomized controlled trial. Probabilistic sensitivity analyses were conducted to examine the uncertainty around the estimated incremental cost-effectiveness ratio using Monte Carlo simulation. Choosing a sedation strategy with propofol resulted in average savings of $17.33 (95% confidence interval [CI] = $24.13 to $10.44) per sedation performed. This resulted in an incremental cost-effectiveness ratio of -$597.03 (95% credibility interval -$6,434.03 to $6,113.57) indicating savings of $597.03 per additional successful sedation performed with propofol. This result was driven by shorter recovery times and was robust to all sensitivity analyses performed. These results indicate that using propofol for PS in the ED is a cost-saving strategy.

Cost-Effectiveness of Oral Anticoagulants for Ischemic Stroke Prophylaxis Among Nonvalvular Atrial Fibrillation Patients.

PubMed

Shah, Anuj; Shewale, Anand; Hayes, Corey J; Martin, Bradley C

2016-06-01

The objective of the study is to compare the cost-effectiveness of oral anticoagulants among atrial fibrillation patients at an increased stroke risk. A Markov model was constructed to project the lifetime costs and quality-adjusted survival (QALYs) of oral anticoagulants using a private payer's perspective. The distribution of stroke risk (CHADS2 score: congestive heart failure, hypertension, advanced age, diabetes mellitus, stroke) and age of the modeled population was derived from a cohort of commercially insured patients with new-onset atrial fibrillation. Probabilities of treatment specific events were derived from published clinical trials. Event and downstream costs were determined from the cost of illness studies. Drug costs were obtained from 2015 National Average Drug Acquisition Cost data. In the base case analysis, warfarin was the least costly ($46 241; 95% CI, 44 499-47 874) and apixaban had the highest QALYs (9.38; 95% CI, 9.24-9.48 QALYs). Apixaban was found to be a cost-effective strategy over warfarin (incremental cost-effectiveness ratio=$25 816) and dominated other anticoagulants. Probabilistic sensitivity analysis showed that apixaban had at least a 61% chance of being the most cost-effective strategy at willingness to pay value of $100 000 per QALY. Among patients with CHADS2 ≥3, dabigatran was the dominant strategy. The model was sensitive to efficacy estimates of apixaban, dabigatran, and edoxaban and the cost of these drugs. All the newer oral anticoagulants compared were more effective than adjusted dosed warfarin. Our model showed that apixaban was the most effective anticoagulant in a general atrial fibrillation population and has an incremental cost-effectiveness ratio <$50 000/QALY. For those with higher stroke risk (CHADS2≥3), dabigatran was the most cost-effective treatment option. © 2016 American Heart Association, Inc.

Medialization thyroplasty versus injection laryngoplasty: a cost minimization analysis.

PubMed

Tam, Samantha; Sun, Hongmei; Sarma, Sisira; Siu, Jennifer; Fung, Kevin; Sowerby, Leigh

2017-02-20

Medialization thyroplasty and injection laryngoplasty are widely accepted treatment options for unilateral vocal fold paralysis. Although both procedures result in similar clinical outcomes, little is known about the corresponding medical care costs. Medialization thyroplasty requires expensive operating room resources while injection laryngoplasty utilizes outpatient resources but may require repeated procedures. The purpose of this study, therefore, is to quantify the cost differences in adult patients with unilateral vocal fold paralysis undergoing medialization thyroplasty versus injection laryngoplasty. Cost minimization analysis conducted using a decision tree model. A decision tree model was constructed to capture clinical scenarios for medialization thyroplasty and injection laryngoplasty. Probabilities for various events were obtained from a retrospective cohort from the London Health Sciences Centre, Canada. Costs were derived from the published literature and the London Health Science Centre. All costs were reported in 2014 Canadian dollars. Time horizon was 5 years. The study was conducted from an academic hospital perspective in Canada. Various sensitivity analyses were conducted to assess differences in procedure-specific costs and probabilities of key events. Sixty-three patients underwent medialization thyroplasty and 41 underwent injection laryngoplasty. Cost of medialization thyroplasty was C$2499.10 per patient whereas those treated with injection laryngoplasty cost C$943.19. Results showed that cost savings with IL were C$1555.91. Deterministic and probabilistic sensitivity analyses suggested cost savings ranged from C$596 to C$3626. Treatment with injection laryngoplasty results in cost savings of C$1555.91 per patient. Our extensive sensitivity analyses suggest that switching from medialization thyroplasty to injection laryngoplasty will lead to a minimum cost savings of C$596 per patient. Considering the significant cost savings and similar effectiveness, injection laryngoplasty should be strongly considered as a preferred treatment option for patients diagnosed with unilateral vocal fold paralysis.

Probabilistic Simulation of Stress Concentration in Composite Laminates

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Murthy, P. L. N.; Liaw, D. G.

1994-01-01

A computational methodology is described to probabilistically simulate the stress concentration factors (SCF's) in composite laminates. This new approach consists of coupling probabilistic composite mechanics with probabilistic finite element structural analysis. The composite mechanics is used to probabilistically describe all the uncertainties inherent in composite material properties, whereas the finite element is used to probabilistically describe the uncertainties associated with methods to experimentally evaluate SCF's, such as loads, geometry, and supports. The effectiveness of the methodology is demonstrated by using is to simulate the SCF's in three different composite laminates. Simulated results match experimental data for probability density and for cumulative distribution functions. The sensitivity factors indicate that the SCF's are influenced by local stiffness variables, by load eccentricities, and by initial stress fields.

Economic Evaluation of Endoscopic Sinus Surgery versus Continued Medical Therapy for Refractory Chronic Rhinosinusitis

PubMed Central

Rudmik, Luke; Soler, Zachary M.; Mace, Jess C.; Schlosser, Rodney J.; Smith, Timothy L.

2014-01-01

Objective To evaluate the long-term cost-effectiveness of endoscopic sinus surgery (ESS) compared to continued medical therapy for patients with refractory chronic rhinosinusitis (CRS). Study Design Cohort-style Markov decision tree economic evaluation Methods The economic perspective was the US third party payer with a 30 year time horizon. The two comparative treatment strategies were: 1) ESS followed by appropriate postoperative medical therapy and 2) continued medical therapy alone. Primary outcome was the incremental cost per quality adjusted life year (QALY). Costs were discounted at a rate of 3.5% in the reference case. Multiple sensitivity analyses were performed including differing time-horizons, discounting scenarios, and a probabilistic sensitivity analysis (PSA). Results The reference case demonstrated that the ESS strategy cost a total of $48,838.38 and produced a total of 20.50 QALYs. The medical therapy alone strategy cost a total of $28,948.98 and produced a total of 17.13 QALYs. The incremental cost effectiveness ratio (ICER) for ESS versus medical therapy alone is $5,901.90 per QALY. The cost-effectiveness acceptability curve from the PSA demonstrated that there is 74% certainty that the ESS strategy is the most cost-effective decision for any willingness to pay threshold greater then $25,000. The time horizon analysis suggests that ESS becomes the cost-effective intervention within the 3rd year after surgery. Conclusion Results from this study suggest that employing an ESS treatment strategy is the most cost-effective intervention compared to continued medical therapy alone for the long-term management of patients with refractory CRS. PMID:25186499

Risk Informed Design and Analysis Criteria for Nuclear Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salmon, Michael W.

2015-06-17

Target performance can be achieved by defining design basis ground motion from results of a probabilistic seismic hazards assessment, and introducing known levels of conservatism in the design above the DBE. ASCE 4, 43, DOE-STD-1020 defined the DBE at 4x10-4 and introduce only slight levels of conservatism in response. ASCE 4, 43, DOE-STD-1020 assume code capacities shoot for about 98% NEP. There is a need to have a uniform target (98% NEP) for code developers (ACI, AISC, etc.) to aim for. In considering strengthening options, one must also consider cost/risk reduction achieved.

Safe Life Propulsion Design Technologies (3rd Generation Propulsion Research and Technology)

NASA Technical Reports Server (NTRS)

Ellis, Rod

2000-01-01

The tasks outlined in this viewgraph presentation on safe life propulsion design technologies (third generation propulsion research and technology) include the following: (1) Ceramic matrix composite (CMC) life prediction methods; (2) Life prediction methods for ultra high temperature polymer matrix composites for reusable launch vehicle (RLV) airframe and engine application; (3) Enabling design and life prediction technology for cost effective large-scale utilization of MMCs and innovative metallic material concepts; (4) Probabilistic analysis methods for brittle materials and structures; (5) Damage assessment in CMC propulsion components using nondestructive characterization techniques; and (6) High temperature structural seals for RLV applications.

Cost-Effectiveness and Cost-Utility Analysis of Ingenol Mebutate Versus Diclofenac 3% and Imiquimod 5% in the Treatment of Actinic Keratosis in Spain.

PubMed

Elías, I; Ortega-Joaquín, N; de la Cueva, P; Del Pozo, L J; Moreno-Ramírez, D; Boada, A; Aguilar, M; Mirada, A; Mosquera, E; Gibbons, C; Oyagüez, I

2016-01-01

To perform a cost-effectiveness and cost-utility analysis of ingenol mebutate in the treatment of actinic keratosis in Spain. We used an adapted Markov model to simulate outcomes in a cohort of patients (mean age, 73 years) with actinic keratosis over a 5-year period. The comparators were diclofenac 3% and imiquimod 5%. The analysis was performed from the perspective of the Spanish National Health System based on direct costs (2015 retail price plus value added tax less the mandatory discount). A panel of experts estimated resources, taking unit costs from national databases. An annual discount rate of 3% was applied. Deterministic and probabilistic sensitivity analyses were performed. The effectiveness of ingenol mebutate-with 0.192 and 0.129 more clearances gained in treatments for face and scalp lesions and trunk and extremity lesions, respectively-was superior to diclofenac's. The total costs of treatment with ingenol mebutate were lower at € 551.50 (face and scalp) and € 622.27 (trunk and extremities) than the respective costs with diclofenac (€ 849.11 and € 844.93). The incremental cost-effectiveness and cost-utility ratios showed that ingenol mebutate was a dominant strategy vs diclofenac. Ingenol mebutate also proved to be more effective than imiquimod, based on 0.535 and 0.503 additional clearances, and total costs of € 551.50 and € 527.89 for the two drugs, respectively. The resulting incremental cost-effectiveness ratio was € 728.64 per clearance gained with ingenol mebutate vs imiquimod. Ingenol mebutate was a dominant treatment option vs diclofenac and was efficient vs imiquimod (i.e., more effective at a higher cost, achieving an incremental cost-utility ratio of<€30000/quality-adjusted life-years). Copyright © 2016 AEDV. Published by Elsevier España, S.L.U. All rights reserved.

[Cost-effectiveness analysis of sofosbuvir, peginterferon and ribavirin in patients with chronic hepatitis C: Early treatment in the initial stage of fibrosis vs. delayed treatment in advanced fibrosis].

PubMed

Buti, María; Domínguez-Hernández, Raquel; Oyagüez, Itziar; Casado, Miguel Ángel

2016-01-01

Cost-effectiveness analysis of sofosbuvir combined with peginterferon alpha-2a and ribavirin (SOF/Peg-IFN/RBV) in early versus advanced fibrosis in previously untreated patients with chronic hepatitis C genotype 1 (CHC-GT1), from the perspective of the Spanish National Health System (NHS). A Markov model was developed to compare lifetime costs and outcomes (life years gained [LYGs] and quality-adjusted life years [QALYs]) of 2 treatment strategies: SOF/Peg-IFN/RBV administered during early fibrosis (mild-moderate fibrosis; F2-F3) or advanced fibrosis (cirrhosis; F4). Efficacy (sustained virologic response), annual transition probabilities, disease management costs and utilities were obtained from the literature. Costs and outcomes were discounted annually at 3%. Direct costs were considered, expressed in Euros (€, 2014). Probabilistic sensitivity analysis (PSA) was also performed. SOF/Peg-IFN/RBV therapy at F2-F3 was more effective (19.12 LYGs and 14.14 QALYs) compared to F4. In a cohort of 1,000 patients, SOF/Peg-IFN/RBV prevented 66 cases of decompensated cirrhosis, 60 hepatocellular carcinomas and 4 liver transplantations compared with therapy in advanced fibrosis. The total lifetime cost of early therapy (€43,263) was less than the cost of treatment in the advanced stage (€49,018). Early therapy was a dominant strategy, more effective and less costly in all simulations. In the PSA analysis, administration of SOF/PEG-IFN/RBV at F2-F3 was dominant in all simulations. Starting SOF/Peg-IFN/RBV therapy at F2-F3, compared with therapy at F4, reduced the incidence of liver disease complications and was associated with cost savings for the Spanish NHS in CHC-GT1 patients. Copyright © 2016 Elsevier España, S.L.U. y AEEH y AEG. All rights reserved.

Cost-effectiveness of dabigatran etexilate in the prevention of stroke and systemic embolism in patients with atrial fibrillation in Belgium.

PubMed

Wouters, Hanne; Thijs, Vincent; Annemans, Lieven

2013-01-01

To assess the cost-effectiveness of dabigatran etexilate ('dabigatran') vs vitamin K antagonists (VKAs) in the Belgian healthcare setting for the prevention of stroke and systemic embolism (SE) in patients with non-valvular atrial fibrillation (AF). A Markov model was used to calculate the cost-effectiveness of dabigatran vs VKAs in Belgium, whereby warfarin was considered representative for the VKA class. Efficacy and safety data were taken from the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial and a network meta-analysis. Local resource use and unit costs were included in the model. Effectiveness was expressed in Quality Adjusted Life-Years (QALYs). The model outcomes were total costs, total QALYs, incremental costs, incremental QALYs and the incremental cost-effectiveness ratio (ICER). The level of International Normalized Ratio (INR) control and the use of other antithrombotic therapies observed in Belgian clinical practice were reflected in two scenario analyses. In the base case analysis, total costs per patient were €13,333 for dabigatran and €12,454 for warfarin. Total QALYs per patient were 9.51 for dabigatran and 9.19 for warfarin. The corresponding ICER was €2807/QALY. The ICER of dabigatran was €970/QALY vs warfarin with real-world INR control and €5296/QALY vs a mix of warfarin, aspirin, and no treatment. Results were shown to be robust in one-way and probabilistic sensitivity analyses. The analysis does not include long-term costs for clinical events, as these data were not available for Belgium. As in any economic model based on data from a randomized clinical trial, several assumptions had to be made when extrapolating results to routine clinical practice in Belgium. This analysis suggests that dabigatran, a novel oral anticoagulant, is a cost-effective treatment for the prevention of stroke and SE in patients with non-valvular AF in the Belgian healthcare setting.

Cost-Effectiveness Analysis of Different Genetic Testing Strategies for Lynch Syndrome in Taiwan.

PubMed

Chen, Ying-Erh; Kao, Sung-Shuo; Chung, Ren-Hua

2016-01-01

Patients with Lynch syndrome (LS) have a significantly increased risk of developing colorectal cancer (CRC) and other cancers. Genetic screening for LS among patients with newly diagnosed CRC aims to identify mutations in the disease-causing genes (i.e., the DNA mismatch repair genes) in the patients, to offer genetic testing for relatives of the patients with the mutations, and then to provide early prevention for the relatives with the mutations. Several genetic tests are available for LS, such as DNA sequencing for MMR genes and tumor testing using microsatellite instability and immunohistochemical analyses. Cost-effectiveness analyses of different genetic testing strategies for LS have been performed in several studies from different countries such as the US and Germany. However, a cost-effectiveness analysis for the testing has not yet been performed in Taiwan. In this study, we evaluated the cost-effectiveness of four genetic testing strategies for LS described in previous studies, while population-specific parameters, such as the mutation rates of the DNA mismatch repair genes and treatment costs for CRC in Taiwan, were used. The incremental cost-effectiveness ratios based on discounted life years gained due to genetic screening were calculated for the strategies relative to no screening and to the previous strategy. Using the World Health Organization standard, which was defined based on Taiwan's Gross Domestic Product per capita, the strategy based on immunohistochemistry as a genetic test followed by BRAF mutation testing was considered to be highly cost-effective relative to no screening. Our probabilistic sensitivity analysis results also suggest that the strategy has a probability of 0.939 of being cost-effective relative to no screening based on the commonly used threshold of $50,000 to determine cost-effectiveness. To the best of our knowledge, this is the first cost-effectiveness analysis for evaluating different genetic testing strategies for LS in Taiwan. The results will be informative for the government when considering offering screening for LS in patients newly diagnosed with CRC.

Are financial incentives cost-effective to support smoking cessation during pregnancy?

PubMed

Boyd, Kathleen A; Briggs, Andrew H; Bauld, Linda; Sinclair, Lesley; Tappin, David

2016-02-01

To investigate the cost-effectiveness of up to £400 worth of financial incentives for smoking cessation in pregnancy as an adjunct to routine health care. Cost-effectiveness analysis based on a Phase II randomized controlled trial (RCT) and a cost-utility analysis using a life-time Markov model. The RCT was undertaken in Glasgow, Scotland. The economic analysis was undertaken from the UK National Health Service (NHS) perspective. A total of 612 pregnant women randomized to receive usual cessation support plus or minus financial incentives of up to £400 vouchers (US $609), contingent upon smoking cessation. Comparison of usual support and incentive interventions in terms of cotinine-validated quitters, quality-adjusted life years (QALYs) and direct costs to the NHS. The incremental cost per quitter at 34-38 weeks pregnant was £1127 ($1716).This is similar to the standard look-up value derived from Stapleton & West's published ICER tables, £1390 per quitter, by looking up the Cessation in Pregnancy Incentives Trial (CIPT) incremental cost (£157) and incremental 6-month quit outcome (0.14). The life-time model resulted in an incremental cost of £17 [95% confidence interval (CI) = -£93, £107] and a gain of 0.04 QALYs (95% CI = -0.058, 0.145), giving an ICER of £482/QALY ($734/QALY). Probabilistic sensitivity analysis indicates uncertainty in these results, particularly regarding relapse after birth. The expected value of perfect information was £30 million (at a willingness to pay of £30 000/QALY), so given current uncertainty, additional research is potentially worthwhile. Financial incentives for smoking cessation in pregnancy are highly cost-effective, with an incremental cost per quality-adjusted life years of £482, which is well below recommended decision thresholds. © 2015 Society for the Study of Addiction.

The cost-effectiveness of etanercept in patients with severe ankylosing spondylitis in the UK.

PubMed

Ara, R M; Reynolds, A V; Conway, P

2007-08-01

To examine the costs and benefits associated with long-term etanercept (ETN) treatment in patients with severe ankylosing spondylitis (AS) in the UK in accordance with the BSR guidelines. A mathematical model was constructed to estimate the costs and benefits associated with ETN plus non-steroidal anti-inflammatory drugs (NSAIDs) compared with NSAIDs alone. Individual patient data from Phase III RCTs was used to inform the proportion and magnitude of initial response to treatment and changes in health-related quality of life. A retrospective costing exercise on patients attending a UK secondary care rheumatology unit was used to inform disease costs. Published evidence on long-term disease progression was extrapolated over a 25-yr horizon. Uncertainty was examined using probabilistic sensitivity analyses. Over a 25-yr horizon, ETN plus NSAIDs gave 1.58 more QALYs at an additional cost of 35,978 pounds when compared with NSAID treatment alone. This equates to a central estimate of 22,700 pounds per QALY. The incremental cost per QALYs using shorter time periods were 27,600 pounds, 23,600 pounds and 22,600 pounds at 2, 5 and 15 yrs, respectively. Using a 25-yr horizon, 93% of results from the probabilistic analyses fall below a threshold of 25,000 pounds per QALY. This study demonstrates the potential cost-effectiveness of ETN plus NSAIDs compared with NSAIDs alone in patients with severe AS treated according to the BSR guidelines in the UK.

Probabilistic estimation of numbers and costs of future landslides in the San Francisco Bay region

USGS Publications Warehouse

Crovelli, R.A.; Coe, J.A.

2009-01-01

We used historical records of damaging landslides triggered by rainstorms and a newly developed Probabilistic Landslide Assessment Cost Estimation System (PLACES) to estimate the numbers and direct costs of future landslides in the 10-county San Francisco Bay region. Historical records of damaging landslides in the region are incomplete. Therefore, our estimates of numbers and costs of future landslides are minimal estimates. The estimated mean annual number of future damaging landslides for the entire 10-county region is about 65. Santa Cruz County has the highest estimated mean annual number of damaging future landslides (about 18), whereas Napa, San Francisco, and Solano Counties have the lowest estimated mean numbers of damaging landslides (about 1 each). The estimated mean annual cost of future landslides in the entire region is about US $14.80 million (year 2000 $). The estimated mean annual cost is highest for San Mateo County ($3.24 million) and lowest for Solano County ($0.18 million). The annual per capita cost for the entire region will be about $2.10. Santa Cruz County will have the highest annual per capita cost at $8.45, whereas San Francisco County will have the lowest per capita cost at $0.31. Normalising costs by dividing by the percentage of land area with slopes equal to or greater than 17% indicates that San Francisco County will have the highest cost per square km ($7,101), whereas Santa Clara County will have the lowest cost per square km ($229). These results indicate that the San Francisco Bay region has one of the highest levels of landslide risk in the United States. Compared with landslide cost estimates from the rest of the world, the risk level in the Bay region seems high, but not exceptionally high.

The application of probabilistic fracture analysis to residual life evaluation of embrittled reactor vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, T.L.; Simonen, F.A.

1992-05-01

Probabilistic fracture mechanics analysis is a major element of comprehensive probabilistic methodology on which current NRC regulatory requirements for pressurized water reactor vessel integrity evaluation are based. Computer codes such as OCA-P and VISA-II perform probabilistic fracture analyses to estimate the increase in vessel failure probability that occurs as the vessel material accumulates radiation damage over the operating life of the vessel. The results of such analyses, when compared with limits of acceptable failure probabilities, provide an estimation of the residual life of a vessel. Such codes can be applied to evaluate the potential benefits of plant-specific mitigating actions designedmore » to reduce the probability of failure of a reactor vessel. 10 refs.« less

The application of probabilistic fracture analysis to residual life evaluation of embrittled reactor vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, T.L.; Simonen, F.A.

1992-01-01

Probabilistic fracture mechanics analysis is a major element of comprehensive probabilistic methodology on which current NRC regulatory requirements for pressurized water reactor vessel integrity evaluation are based. Computer codes such as OCA-P and VISA-II perform probabilistic fracture analyses to estimate the increase in vessel failure probability that occurs as the vessel material accumulates radiation damage over the operating life of the vessel. The results of such analyses, when compared with limits of acceptable failure probabilities, provide an estimation of the residual life of a vessel. Such codes can be applied to evaluate the potential benefits of plant-specific mitigating actions designedmore » to reduce the probability of failure of a reactor vessel. 10 refs.« less

Cost-effectiveness of nivolumab for recurrent or metastatic head and neck cancer☆.

PubMed

Ward, Matthew C; Shah, Chirag; Adelstein, David J; Geiger, Jessica L; Miller, Jacob A; Koyfman, Shlomo A; Singer, Mendel E

2017-11-01

Nivolumab is the first drug to demonstrate a survival benefit for platinum-refractory recurrent or metastatic head and neck cancer. We performed a cost-utility analysis to assess the economic value of nivolumab as compared to alternative standard agents in this context. Using data from the CheckMate 141 trial, we constructed a Markov simulation model from the US payer's perspective to evaluate the cost-effectiveness of nivolumab compared to physician choice of either cetuximab, methotrexate or docetaxel. Alternative strategies considered included: single-agent cetuximab, methotrexate or docetaxel, or first testing for PD-L1 to select for nivolumab. Costs were extracted from Medicare and utilities from the literature and CheckMate. Probabilistic sensitivity analysis (PSA) was used to evaluate parameter uncertainty. $100,000/QALY was the primary threshold for cost-effectiveness. When comparing nivolumab to the standard arm of CheckMate, nivolumab demonstrated an incremental cost-effectiveness ratio (ICER) of $140,672/QALY. When comparing standard therapies, methotrexate was the most cost-effective with similar results for docetaxel. Nivolumab was cost-effective compared to single-agent cetuximab (ICER $89,786/QALY). Treatment selection by PD-L1 immunohistochemistry did not markedly improve the cost-effectiveness of nivolumab. Factors likely to positively impact the cost-effectiveness of nivolumab include better baseline quality-of-life, poor tolerability of standard treatments and/or a lower cost of nivolumab. Nivolumab is preferred to single-agent cetuximab but requires a willingness-to-pay of at least $150,000/QALY to be considered cost-effective when compared to docetaxel or methotrexate. Selection by PD-L1 does not markedly improve the cost-effectiveness of nivolumab. This informs patient selection and clinical care-path development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stapled hemorrhoidopexy, an innovative surgical procedure for hemorrhoidal prolapse: cost-utility analysis.

PubMed

Ribarić, Goran; Kofler, Justus; Jayne, David G

2011-08-15

To undertake full economic evaluation of stapled hemorrhoidopexy (PPH) to establish its cost-effectiveness and investigate whether PPH can become cost-saving compared to conventional excisional hemorrhoidectomy (CH). A cost-utility analysis in hospital and health care system (UK) was undertaken using a probabilistic, cohort-based decision tree to compare the use of PPH with CH. Sensitivity analyses allowed showing outcomes in regard to the variations in clinical practice of PPH procedure. The participants were patients undergoing initial surgical treatment of third and fourth degree hemorrhoids within a 1-year time-horizon. Data on clinical effectiveness were obtained from a systematic review of the literature. Main outcome measures were the cost per procedure at the hospital level, total direct costs from the health care system perspective, quality adjusted life years (QALY) gained and incremental cost per QALY gained. A decrease in operating theater time and hospital stay associated with PPH led to a cost saving compared to CH of GBP 27 (US $43.11, €30.50) per procedure at the hospital level and to an incremental cost of GBP 33 (US $52.68, €37.29) after one year from the societal perspective. Calculation of QALYs induced an incremental QALY of 0.0076 and showed an incremental cost-effective ratio (ICER) of GBP 4316 (US $6890.47, €4878.37). Taking into consideration recent literature on clinical outcomes, PPH becomes cost saving compared to CH for the health care system. PPH is a cost-effective procedure with an ICER of GBP 4136 and it seems that an innovative surgical procedure could be cost saving in routine clinical practice.

Rocket engine system reliability analyses using probabilistic and fuzzy logic techniques

NASA Technical Reports Server (NTRS)

Hardy, Terry L.; Rapp, Douglas C.

1994-01-01

The reliability of rocket engine systems was analyzed by using probabilistic and fuzzy logic techniques. Fault trees were developed for integrated modular engine (IME) and discrete engine systems, and then were used with the two techniques to quantify reliability. The IRRAS (Integrated Reliability and Risk Analysis System) computer code, developed for the U.S. Nuclear Regulatory Commission, was used for the probabilistic analyses, and FUZZYFTA (Fuzzy Fault Tree Analysis), a code developed at NASA Lewis Research Center, was used for the fuzzy logic analyses. Although both techniques provided estimates of the reliability of the IME and discrete systems, probabilistic techniques emphasized uncertainty resulting from randomness in the system whereas fuzzy logic techniques emphasized uncertainty resulting from vagueness in the system. Because uncertainty can have both random and vague components, both techniques were found to be useful tools in the analysis of rocket engine system reliability.

The analysis of the possibility of using 10-minute rainfall series to determine the maximum rainfall amount with 5 minutes duration

NASA Astrophysics Data System (ADS)

Kaźmierczak, Bartosz; Wartalska, Katarzyna; Wdowikowski, Marcin; Kotowski, Andrzej

2017-11-01

Modern scientific research in the area of heavy rainfall analysis regarding to the sewerage design indicates the need to develop and use probabilistic rain models. One of the issues that remains to be resolved is the length of the shortest amount of rain to be analyzed. It is commonly believed that the best time is 5 minutes, while the least rain duration measured by the national services is often 10 or even 15 minutes. Main aim of this paper is to present the difference between probabilistic rainfall models results given from rainfall time series including and excluding 5 minutes rainfall duration. Analysis were made for long-time period from 1961-2010 on polish meteorological station Legnica. To develop best fitted to measurement rainfall data probabilistic model 4 probabilistic distributions were used. Results clearly indicates that models including 5 minutes rainfall duration remains more appropriate to use.

Time Alignment as a Necessary Step in the Analysis of Sleep Probabilistic Curves

NASA Astrophysics Data System (ADS)

Rošt'áková, Zuzana; Rosipal, Roman

2018-02-01

Sleep can be characterised as a dynamic process that has a finite set of sleep stages during the night. The standard Rechtschaffen and Kales sleep model produces discrete representation of sleep and does not take into account its dynamic structure. In contrast, the continuous sleep representation provided by the probabilistic sleep model accounts for the dynamics of the sleep process. However, analysis of the sleep probabilistic curves is problematic when time misalignment is present. In this study, we highlight the necessity of curve synchronisation before further analysis. Original and in time aligned sleep probabilistic curves were transformed into a finite dimensional vector space, and their ability to predict subjects' age or daily measures is evaluated. We conclude that curve alignment significantly improves the prediction of the daily measures, especially in the case of the S2-related sleep states or slow wave sleep.

Probabilistic classifiers with high-dimensional data

PubMed Central

Kim, Kyung In; Simon, Richard

2011-01-01

For medical classification problems, it is often desirable to have a probability associated with each class. Probabilistic classifiers have received relatively little attention for small n large p classification problems despite of their importance in medical decision making. In this paper, we introduce 2 criteria for assessment of probabilistic classifiers: well-calibratedness and refinement and develop corresponding evaluation measures. We evaluated several published high-dimensional probabilistic classifiers and developed 2 extensions of the Bayesian compound covariate classifier. Based on simulation studies and analysis of gene expression microarray data, we found that proper probabilistic classification is more difficult than deterministic classification. It is important to ensure that a probabilistic classifier is well calibrated or at least not “anticonservative” using the methods developed here. We provide this evaluation for several probabilistic classifiers and also evaluate their refinement as a function of sample size under weak and strong signal conditions. We also present a cross-validation method for evaluating the calibration and refinement of any probabilistic classifier on any data set. PMID:21087946

Cost-effectiveness analysis of 30-month vs 12-month dual antiplatelet therapy with clopidogrel and aspirin after drug-eluting stents in patients with acute coronary syndrome.

PubMed

Jiang, Minghuan; You, Joyce H S

2017-10-01

Continuation of dual antiplatelet therapy (DAPT) beyond 1 year reduces late stent thrombosis and ischemic events after drug-eluting stents (DES) but increases risk of bleeding. We hypothesized that extending DAPT from 12 months to 30 months in patients with acute coronary syndrome (ACS) after DES is cost-effective. A lifelong decision-analytic model was designed to simulate 2 antiplatelet strategies in event-free ACS patients who had completed 12-month DAPT after DES: aspirin monotherapy (75-162 mg daily) and continuation of DAPT (clopidogrel 75 mg daily plus aspirin 75-162 mg daily) for 18 months. Clinical event rates, direct medical costs, and quality-adjusted life-years (QALYs) gained were the primary outcomes from the US healthcare provider perspective. Base-case results showed DAPT continuation gained higher QALYs (8.1769 vs 8.1582 QALYs) at lower cost (USD42 982 vs USD44 063). One-way sensitivity analysis found that base-case QALYs were sensitive to odds ratio (OR) of cardiovascular death with DAPT continuation and base-case cost was sensitive to OR of nonfatal stroke with DAPT continuation. DAPT continuation remained cost-effective when the ORs of nonfatal stroke and cardiovascular death were below 1.241 and 1.188, respectively. In probabilistic sensitivity analysis, DAPT continuation was the preferred strategy in 74.75% of 10 000 Monte Carlo simulations at willingness-to-pay threshold of 50 000 USD/QALYs. Continuation of DAPT appears to be cost-effective in ACS patients who were event-free for 12-month DAPT after DES. The cost-effectiveness of DAPT for 30 months was highly subject to the OR of nonfatal stroke and OR of death with DAPT continuation. © 2017 Wiley Periodicals, Inc.

Coronary computed tomography versus exercise testing in patients with stable chest pain: comparative effectiveness and costs.

PubMed

Genders, Tessa S S; Ferket, Bart S; Dedic, Admir; Galema, Tjebbe W; Mollet, Nico R A; de Feyter, Pim J; Fleischmann, Kirsten E; Nieman, Koen; Hunink, M G Myriam

2013-08-20

To determine the comparative effectiveness and costs of a CT-strategy and a stress-electrocardiography-based strategy (standard-of-care; SOC-strategy) for diagnosing coronary artery disease (CAD). A decision analysis was performed based on a well-documented prospective cohort of 471 outpatients with stable chest pain with follow-up combined with best-available evidence from the literature. Outcomes were correct classification of patients as CAD- (no obstructive CAD), CAD+ (obstructive CAD without revascularization) and indication for Revascularization (using a combination reference standard), diagnostic costs, lifetime health care costs, and quality-adjusted life years (QALY). Parameter uncertainty was analyzed using probabilistic sensitivity analysis. For men (and women), diagnostic cost savings were €245 (€252) for the CT-strategy as compared to the SOC-strategy. The CT-strategy classified 82% (88%) of simulated men (women) in the appropriate disease category, whereas 83% (85%) were correctly classified by the SOC-strategy. The long-term cost-effectiveness analysis showed that the SOC-strategy was dominated by the CT-strategy, which was less expensive (-€229 in men, -€444 in women) and more effective (+0.002 QALY in men, +0.005 in women). The CT-strategy was cost-saving (-€231) but also less effective compared to SOC (-0.003 QALY) in men with a pre-test probability of ≥ 70%. The CT-strategy was cost-effective in 100% of simulations, except for men with a pre-test probability ≥ 70% in which case it was 59%. The results suggest that a CT-based strategy is less expensive and equally effective compared to SOC in all women and in men with a pre-test probability <70%. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Cost-effectiveness of Ingenol Mebutate Gel for the Treatment of Actinic Keratosis in Greece.

PubMed

Athanasakis, Kostas; Boubouchairopoulou, Nadia; Tarantilis, Filippos; Tsiantou, Vasiliki; Kontodimas, Stathis; Kyriopoulos, John

2017-05-01

The present study aimed to perform a cost-effectiveness analysis of ingenol mebutate (IM) versus other topical alternatives for the treatment of actinic keratosis (AK). The analysis used a decision tree to calculate the clinical effects and costs of AK first-line treatments, IM (2-3 days), diclofenac 3% (for 8 or 12 weeks), imiquimod 5% (for 4 or 8 weeks), during a 24-month horizon, using discrete intervals of 6 months. A hypothetical cohort of immunocompetent adult patients with clinically confirmed AK on the face and scalp or trunk and extremities was considered. Clinical data on the relative efficacy were obtained from a network meta-analysis. Inputs concerning resource use derived from an expert panel. All costs were calculated from a Greek third-party payer perspective. IM 0.015% and 0.05% were both cost-effective compared with diclofenac and below a willingness-to-pay threshold of €30,000 per quality-adjusted life-year (QALY) (€199 and €167 per QALY, respectively). Comparing IM on the face and scalp AK lesions for 3 days versus imiquimod for 4 weeks resulted in an incremental cost-effectiveness ratio of €10,868 per QALY. IM was dominant during the 8-week imiquimod period. IM use on the trunk and extremities compared with diclofenac (8 or 12 weeks) led to incremental cost-effectiveness ratios estimated at €1584 and €1316 per QALY accordingly. Results remained robust to deterministic and probabilistic sensitivity analyses. From a social insurance perspective in Greece, IM 0.015% and IM 0.05% could be the most cost-effective first-line topical field treatment options in all cases for AK treatment. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Cost-effectiveness analysis comparing epidural, patient-controlled intravenous morphine, and continuous wound infiltration for postoperative pain management after open abdominal surgery.

PubMed

Tilleul, P; Aissou, M; Bocquet, F; Thiriat, N; le Grelle, O; Burke, M J; Hutton, J; Beaussier, M

2012-06-01

Continuous wound infiltration (CWI), i.v. patient-controlled analgesia (i.v.-PCA), and epidural analgesia (EDA) are analgesic techniques commonly used for pain relief after open abdominal surgery. The aim of this study was to evaluate the cost-effectiveness of these techniques. A decision analytic model was developed, including values retrieved from clinical trials and from an observational prospective cohort of 85 patients. Efficacy criteria were based on pain at rest (VAS ≤ 30/100 mm at 24 h). Resource use and costs were evaluated from medical record measurements and published data. Probabilistic sensitivity analysis (PSA) was performed. When taking into account all resources consumed, the CWI arm (€ 6460) is economically dominant when compared with i.v.-PCA (€ 7273) and EDA (€ 7500). The proportion of patients successfully controlled for their postoperative pain management are 77.4%, 53.9%, and 72.9% for CWI, i.v.-PCA, and EDA, respectively, demonstrating the CWI procedure to be both economically and clinically dominant. PSA reported that CWI remains cost saving in 70.4% of cases in comparison with EDA and in 59.2% of cases when compared with PCA. Device-related costs of using CWI for pain management after abdominal laparotomy are partly counterbalanced by a reduction in resource consumption. The cost-effectiveness analysis suggests that CWI is the dominant treatment strategy for managing postoperative pain (i.e. more effective and less costly) in comparison with i.v.-PCA. When compared with EDA, CWI is less costly with almost equivalent efficacy. This economic evaluation may be useful for clinicians to design algorithms for pain management after major abdominal surgery.

Cost-effectiveness analysis of a universal mass vaccination program with a PHiD-CV 2+1 schedule in Malaysia.

PubMed

Wang, Xiao Jun; Saha, Ashwini; Zhang, Xu-Hao

2017-01-01

Currently, two pediatric pneumococcal conjugate vaccines are available in the private market of Malaysia-13-valent pneumococcal conjugate vaccine (PCV13) and pneumococcal polysaccharide and non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV). This study aimed to evaluate the cost-effectiveness of a universal mass vaccination program with a PHiD-CV 2+1 schedule versus no vaccination or with a PCV13 2+1 schedule in Malaysia. A published Markov cohort model was adapted to evaluate the epidemiological and economic consequences of programs with no vaccination, a PHiD-CV 2+1 schedule or a PCV13 2+1 schedule over a 10-year time horizon. Disease cases, deaths, direct medical costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were estimated. Locally published epidemiology and cost data were used whenever possible. Vaccine effectiveness and disutility data were based on the best available published data. All data inputs and assumptions were validated by local clinical and health economics experts. Analyses were conducted from the perspective of the Malaysian government for a birth cohort of 508,774. Costs and QALYs were discounted at 3% per annum. One-way and probabilistic sensitivity analyses were performed. Compared with no vaccination, a PHiD-CV 2+1 program was projected to prevent 1109 invasive pneumococcal disease (IPD), 24,679 pneumonia and 72,940 acute otitis media (AOM) cases and 103 IPD/pneumonia deaths over 10 years, with additional costs and QALYs of United States dollars (USD) 30.9 million and 1084 QALYs, respectively, at an ICER of USD 28,497/QALY. Compared with a PCV13 2+1 program, PHiD-CV 2+1 was projected to result in similar reductions in IPD cases (40 cases more) but significantly fewer AOM cases (30,001 cases less), with cost savings and additional QALYs gained of USD 5.2 million and 116 QALYs, respectively, demonstrating dominance over PCV13. Results were robust to variations in one-way and probabilistic sensitivity analyses. A PHiD-CV 2+1 universal mass vaccination program could substantially reduce pneumococcal disease burden versus no vaccination, and was expected to be cost-effective in Malaysia. A PHiD-CV 2+1 program was also expected to be a dominant choice over a PCV13 2+1 program in Malaysia.

Cost-effectiveness of adding novel or group 5 interventions to a background regimen for the treatment of multidrug-resistant tuberculosis in Germany.

PubMed

Wirth, Daniel; Dass, Ramesh; Hettle, Robert

2017-03-08

Treatment of multidrug-resistant tuberculosis (MDR-TB) is complex, lengthy, and involves a minimum of four drugs termed a background regimen (BR), that have not previously been prescribed or that have proven susceptible to patient sputum culture isolates. In recent years, promising new treatment options have emerged as add-on therapies to a BR. The aim of this study was to evaluate the long-term costs and effectiveness of adding the novel or group 5 interventions bedaquiline, delamanid, and linezolid to a background regimen (BR) of drugs for the treatment of adult patients with pulmonary multidrug-resistant tuberculosis (MDR-TB), within their marketing authorisations, from a German healthcare cost-effectiveness perspective. A cohort-based Markov model was developed to simulate the incremental cost-effectiveness ratio of bedaquiline plus BR, delamanid plus BR, or linezolid plus BR versus BR alone in the treatment of MDR-TB, over a 10-year time horizon. Effectiveness of treatment was evaluated in Quality-Adjusted Life-Years (QALYs) and Life-Years Gained (LYG), using inputs from clinical trials for bedaquiline and delamanid and from a German observational study for linezolid. Cost data were obtained from German Drug Directory costs (€/2015), published literature, and expert opinion. A 3% yearly discount rate was applied. Probabilistic and deterministic sensitivity analyses were conducted. The total discounted costs per-patient were €85,575 for bedaquiline plus BR, €81,079 for delamanid plus BR, and €80,460 for linezolid plus BR, compared with a cost of €60,962 for BR alone. The total discounted QALYs per-patient were 5.95 for bedaquiline plus BR, 5.36 for delamanid plus BR, and 3.91 for linezolid plus BR, compared with 3.68 for BR alone. All interventions were therefore associated with higher QALYs and higher costs than BR alone, with incremental costs per QALY gained of €22,238 for bedaquiline, €38,703 for delamanid, and €87,484 for linezolid, versus BR alone. In a fully incremental analysis, bedaquiline plus BR was the most cost-effective treatment option at thresholds greater than €22,000 per QALY gained. In probabilistic analyses, the probability that bedaquiline plus BR was the most cost-effective treatment strategy at a willingness-to-pay threshold of €30,000 was 54.5%, compared with 22.9% for BR alone, 18.2% for delamanid plus BR, and 4.4% for linezolid. In Germany, the addition of bedaquiline, delamanid, or linezolid to a BR would result in QALY gains over BR alone. Based on this analysis, bedaquiline is likely to be the most cost-effective intervention for the treatment of MDR-TB, when added to a BR regimen at thresholds greater than €22,000 per QALY.

Probabilistic Structural Analysis of SSME Turbopump Blades: Probabilistic Geometry Effects

NASA Technical Reports Server (NTRS)

Nagpal, V. K.

1985-01-01

A probabilistic study was initiated to evaluate the precisions of the geometric and material properties tolerances on the structural response of turbopump blades. To complete this study, a number of important probabilistic variables were identified which are conceived to affect the structural response of the blade. In addition, a methodology was developed to statistically quantify the influence of these probabilistic variables in an optimized way. The identified variables include random geometric and material properties perturbations, different loadings and a probabilistic combination of these loadings. Influences of these probabilistic variables are planned to be quantified by evaluating the blade structural response. Studies of the geometric perturbations were conducted for a flat plate geometry as well as for a space shuttle main engine blade geometry using a special purpose code which uses the finite element approach. Analyses indicate that the variances of the perturbations about given mean values have significant influence on the response.

Lunar Exploration Architecture Level Key Drivers and Sensitivities

NASA Technical Reports Server (NTRS)

Goodliff, Kandyce; Cirillo, William; Earle, Kevin; Reeves, J. D.; Shyface, Hilary; Andraschko, Mark; Merrill, R. Gabe; Stromgren, Chel; Cirillo, Christopher

2009-01-01

Strategic level analysis of the integrated behavior of lunar transportation and lunar surface systems architecture options is performed to assess the benefit, viability, affordability, and robustness of system design choices. This analysis employs both deterministic and probabilistic modeling techniques so that the extent of potential future uncertainties associated with each option are properly characterized. The results of these analyses are summarized in a predefined set of high-level Figures of Merit (FOMs) so as to provide senior NASA Constellation Program (CxP) and Exploration Systems Mission Directorate (ESMD) management with pertinent information to better inform strategic level decision making. The strategic level exploration architecture model is designed to perform analysis at as high a level as possible but still capture those details that have major impacts on system performance. The strategic analysis methodology focuses on integrated performance, affordability, and risk analysis, and captures the linkages and feedbacks between these three areas. Each of these results leads into the determination of the high-level FOMs. This strategic level analysis methodology has been previously applied to Space Shuttle and International Space Station assessments and is now being applied to the development of the Constellation Program point-of-departure lunar architecture. This paper provides an overview of the strategic analysis methodology and the lunar exploration architecture analyses to date. In studying these analysis results, the strategic analysis team has identified and characterized key drivers affecting the integrated architecture behavior. These key drivers include inclusion of a cargo lander, mission rate, mission location, fixed-versus- variable costs/return on investment, and the requirement for probabilistic analysis. Results of sensitivity analysis performed on lunar exploration architecture scenarios are also presented.

Space transportation architecture: Reliability sensitivities

NASA Technical Reports Server (NTRS)

Williams, A. M.

1992-01-01

A sensitivity analysis is given of the benefits and drawbacks associated with a proposed Earth to orbit vehicle architecture. The architecture represents a fleet of six vehicles (two existing, four proposed) that would be responsible for performing various missions as mandated by NASA and the U.S. Air Force. Each vehicle has a prescribed flight rate per year for a period of 31 years. By exposing this fleet of vehicles to a probabilistic environment where the fleet experiences failures, downtimes, setbacks, etc., the analysis involves determining the resiliency and costs associated with the fleet of specific vehicle/subsystem reliabilities. The resources required were actual observed data on the failures and downtimes associated with existing vehicles, data based on engineering judgement for proposed vehicles, and the development of a sensitivity analysis program.

Optimally Stopped Optimization

NASA Astrophysics Data System (ADS)

Vinci, Walter; Lidar, Daniel

We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known, and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time, optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark the performance of a D-Wave 2X quantum annealer and the HFS solver, a specialized classical heuristic algorithm designed for low tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N = 1098 variables, the D-Wave device is between one to two orders of magnitude faster than the HFS solver.

75 FR 18205 - Notice of Peer Review Meeting for the External Peer Review Drafts of Two Documents on Using...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-09

... Role of Risk Analysis in Decision-Making AGENCY: Environmental Protection Agency (EPA). ACTION: Notice... documents entitled, ``Using Probabilistic Methods to Enhance the Role of Risk Analysis in Decision- Making... Probabilistic Methods to Enhance the Role of Risk Analysis in Decision-Making, with Case Study Examples'' and...

ProbCD: enrichment analysis accounting for categorization uncertainty.

PubMed

Vêncio, Ricardo Z N; Shmulevich, Ilya

2007-10-12

As in many other areas of science, systems biology makes extensive use of statistical association and significance estimates in contingency tables, a type of categorical data analysis known in this field as enrichment (also over-representation or enhancement) analysis. In spite of efforts to create probabilistic annotations, especially in the Gene Ontology context, or to deal with uncertainty in high throughput-based datasets, current enrichment methods largely ignore this probabilistic information since they are mainly based on variants of the Fisher Exact Test. We developed an open-source R-based software to deal with probabilistic categorical data analysis, ProbCD, that does not require a static contingency table. The contingency table for the enrichment problem is built using the expectation of a Bernoulli Scheme stochastic process given the categorization probabilities. An on-line interface was created to allow usage by non-programmers and is available at: http://xerad.systemsbiology.net/ProbCD/. We present an analysis framework and software tools to address the issue of uncertainty in categorical data analysis. In particular, concerning the enrichment analysis, ProbCD can accommodate: (i) the stochastic nature of the high-throughput experimental techniques and (ii) probabilistic gene annotation.

Water supply infrastructure planning under multiple uncertainties: A differentiated approach

NASA Astrophysics Data System (ADS)

Fletcher, S.; Strzepek, K.

2017-12-01

Many water planners face increased pressure on water supply systems from increasing demands from population and economic growth in combination with uncertain water supply. Supply uncertainty arises from short-term climate variability and long-term climate change as well as uncertainty in groundwater availability. Social and economic uncertainties - such as sectoral competition for water, food and energy security, urbanization, and environmental protection - compound physical uncertainty. Further, the varying risk aversion of stakeholders and water managers makes it difficult to assess the necessity of expensive infrastructure investments to reduce risk. We categorize these uncertainties on two dimensions: whether they can be updated over time by collecting additional information, and whether the uncertainties can be described probabilistically or are "deep" uncertainties whose likelihood is unknown. Based on this, we apply a decision framework that combines simulation for probabilistic uncertainty, scenario analysis for deep uncertainty, and multi-stage decision analysis for uncertainties that are reduced over time with additional information. In light of these uncertainties and the investment costs of large infrastructure, we propose the assessment of staged, modular infrastructure and information updating as a hedge against risk. We apply this framework to cases in Melbourne, Australia and Riyadh, Saudi Arabia. Melbourne is a surface water system facing uncertain population growth and variable rainfall and runoff. A severe drought from 1997 to 2009 prompted investment in a 150 MCM/y reverse osmosis desalination plan with a capital cost of 3.5 billion. Our analysis shows that flexible design in which a smaller portion of capacity is developed initially with the option to add modular capacity in the future can mitigate uncertainty and reduce the expected lifetime costs by up to 1 billion. In Riyadh, urban water use relies on fossil groundwater aquifers and desalination. Intense withdrawals for urban and agricultural use will lead to lowering of the water table in the aquifer at rapid but uncertain rates due to poor groundwater characterization. We assess the potential for additional groundwater data collection and a flexible infrastructure approach similar to that in Melbourne to mitigate risk.