Predictors and Moderators of Treatment Response in Childhood Anxiety Disorders: Results from the CAMS Trial

PubMed Central

Compton, Scott N.; Peris, Tara S.; Almirall, Daniel; Birmaher, Boris; Sherrill, Joel; Kendall, Phillip C.; March, John S.; Gosch, Elizabeth A.; Ginsburg, Golda S.; Rynn, Moira A.; Piacentini, John C.; McCracken, James T.; Keeton, Courtney P.; Suveg, Cynthia M.; Aschenbrand, Sasha G.; Sakolsky, Dara; Iyengar, Satish; Walkup, John T.; Albano, Anne Marie

2014-01-01

Objective To examine predictors and moderators of treatment outcomes among 488 youth ages 7-17 years (50% female; 74% ≤ 12 years) with DSM-IV diagnoses of separation anxiety disorder, social phobia, or generalized anxiety disorder who were randomly assigned to receive either cognitive behavior therapy (CBT), sertraline (SRT), their combination (COMB), or medication management with pill placebo (PBO) in the Child/Adolescent Anxiety Multimodal Study (CAMS). Method Six classes of predictor and moderator variables (22 variables) were identified from the literature and examined using continuous (Pediatric Anxiety Ratings Scale; PARS) and categorical (Clinical Global Impression Scale-Improvement; CGI-I) outcome measures. Results Three baseline variables predicted better outcomes (independent of treatment condition) on the PARS, including low anxiety severity (as measured by parents and independent evaluators) and caregiver strain. No baseline variables were found to predict week 12 responder status (CGI-I). Participant's principal diagnosis moderated treatment outcomes, but only on the PARS. No baseline variables were found to moderate treatment outcomes on week 12 responder status (CGI-I). Discussion Overall, anxious children responded favorably to CAMS treatments. However, having more severe and impairing anxiety, greater caregiver strain, and a principal diagnosis of social phobia were associated with less favorable outcomes. Clinical implications of these findings are discussed. PMID:24417601

Movement measurements at home for multiple sclerosis: walking speed measured by a novel ambient measurement system.

PubMed

Smith, Victoria Mj; Varsanik, Jonathan S; Walker, Rachel A; Russo, Andrew W; Patel, Kevin R; Gabel, Wendy; Phillips, Glenn A; Kimmel, Zebadiah M; Klawiter, Eric C

2018-01-01

Gait disturbance is a major contributor to clinical disability in multiple sclerosis (MS). A sensor was developed to assess walking speed at home for people with MS using infrared technology in real-time without the use of wearables. To develop continuous in-home outcome measures to assess gait in adults with MS. Movement measurements were collected continuously for 8 months from six people with MS. Average walking speed and peak walking speed were calculated from movement data, then analyzed for variability over time, by room (location), and over the course of the day. In-home continuous gait outcomes and variability were correlated with standard in-clinic gait outcomes. Measured in-home average walking speed of participants ranged from 0.33 m/s to 0.96 m/s and peak walking speed ranged from 0.89 m/s to 1.51 m/s. Mean total within-participant coefficient of variation for daily average walking speed and peak walking speed were 10.75% and 10.93%, respectively. Average walking speed demonstrated a moderately strong correlation with baseline Timed 25-Foot Walk (r s  = 0.714, P  = 0.111). New non-wearable technology provides reliable and continuous in-home assessment of walking speed.

Assessing medication effects in the MTA study using neuropsychological outcomes.

PubMed

Epstein, Jeffery N; Conners, C Keith; Hervey, Aaron S; Tonev, Simon T; Arnold, L Eugene; Abikoff, Howard B; Elliott, Glen; Greenhill, Laurence L; Hechtman, Lily; Hoagwood, Kimberly; Hinshaw, Stephen P; Hoza, Betsy; Jensen, Peter S; March, John S; Newcorn, Jeffrey H; Pelham, William E; Severe, Joanne B; Swanson, James M; Wells, Karen; Vitiello, Benedetto; Wigal, Timothy

2006-05-01

While studies have increasingly investigated deficits in reaction time (RT) and RT variability in children with attention deficit/hyperactivity disorder (ADHD), few studies have examined the effects of stimulant medication on these important neuropsychological outcome measures. 316 children who participated in the Multimodal Treatment Study of Children with ADHD (MTA) completed the Conners' Continuous Performance Test (CPT) at the 24-month assessment point. Outcome measures included standard CPT outcomes (e.g., errors of commission, mean hit reaction time (RT)) and RT indicators derived from an Ex-Gaussian distributional model (i.e., mu, sigma, and tau). Analyses revealed significant effects of medication across all neuropsychological outcome measures. Results on the Ex-Gaussian outcome measures revealed that stimulant medication slows RT and reduces RT variability. This demonstrates the importance of including analytic strategies that can accurately model the actual distributional pattern, including the positive skew. Further, the results of the study relate to several theoretical models of ADHD.

Home healthcare nurse retention and patient outcome model: discussion and model development.

PubMed

Ellenbecker, Carol Hall; Cushman, Margaret

2012-08-01

This paper discusses additions to an empirically tested model of home healthcare nurse retention. An argument is made that the variables of shared decision-making and organizational commitment be added to the model based on the authors' previous research and additional evidence from the literature. Previous research testing the home healthcare nurse retention model established empirical relationships between nurse, agency, and area characteristics to nurse job satisfaction, intent to stay, and retention. Unexplained model variance prompted a new literature search to augment understanding of nurse retention and patient and agency outcomes. Data come from the authors' previous research, and a literature search from 1990 to 2011 on the topics organizational commitment, shared decision-making, nurse retention, patient outcomes and agency performance. The literature provides a rationale for the additional variables of shared decision-making and affective and continuous organizational commitment, linking these variables to nurse job satisfaction, nurse intent to stay, nurse retention and patient outcomes and agency performance. Implications for nursing.  The new variables in the model suggest that all agencies, even those not struggling to retain nurses, should develop interventions to enhance nurse job satisfaction to assure quality patient outcomes. The new nurse retention and patient outcome model increases our understanding of nurse retention. An understanding of the relationship among these variables will guide future research and the development of interventions to create and maintain nursing work environments that contribute to nurse affective agency commitment, nurse retention and quality of patient outcomes. © 2011 Blackwell Publishing Ltd.

Stochastic satisficing account of confidence in uncertain value-based decisions

PubMed Central

Bahrami, Bahador; Keramati, Mehdi

2018-01-01

Every day we make choices under uncertainty; choosing what route to work or which queue in a supermarket to take, for example. It is unclear how outcome variance, e.g. uncertainty about waiting time in a queue, affects decisions and confidence when outcome is stochastic and continuous. How does one evaluate and choose between an option with unreliable but high expected reward, and an option with more certain but lower expected reward? Here we used an experimental design where two choices’ payoffs took continuous values, to examine the effect of outcome variance on decision and confidence. We found that our participants’ probability of choosing the good (high expected reward) option decreased when the good or the bad options’ payoffs were more variable. Their confidence ratings were affected by outcome variability, but only when choosing the good option. Unlike perceptual detection tasks, confidence ratings correlated only weakly with decisions’ time, but correlated with the consistency of trial-by-trial choices. Inspired by the satisficing heuristic, we propose a “stochastic satisficing” (SSAT) model for evaluating options with continuous uncertain outcomes. In this model, options are evaluated by their probability of exceeding an acceptability threshold, and confidence reports scale with the chosen option’s thus-defined satisficing probability. Participants’ decisions were best explained by an expected reward model, while the SSAT model provided the best prediction of decision confidence. We further tested and verified the predictions of this model in a second experiment. Our model and experimental results generalize the models of metacognition from perceptual detection tasks to continuous-value based decisions. Finally, we discuss how the stochastic satisficing account of decision confidence serves psychological and social purposes associated with the evaluation, communication and justification of decision-making. PMID:29621325

CGBayesNets: Conditional Gaussian Bayesian Network Learning and Inference with Mixed Discrete and Continuous Data

PubMed Central

Weiss, Scott T.

2014-01-01

Bayesian Networks (BN) have been a popular predictive modeling formalism in bioinformatics, but their application in modern genomics has been slowed by an inability to cleanly handle domains with mixed discrete and continuous variables. Existing free BN software packages either discretize continuous variables, which can lead to information loss, or do not include inference routines, which makes prediction with the BN impossible. We present CGBayesNets, a BN package focused around prediction of a clinical phenotype from mixed discrete and continuous variables, which fills these gaps. CGBayesNets implements Bayesian likelihood and inference algorithms for the conditional Gaussian Bayesian network (CGBNs) formalism, one appropriate for predicting an outcome of interest from, e.g., multimodal genomic data. We provide four different network learning algorithms, each making a different tradeoff between computational cost and network likelihood. CGBayesNets provides a full suite of functions for model exploration and verification, including cross validation, bootstrapping, and AUC manipulation. We highlight several results obtained previously with CGBayesNets, including predictive models of wood properties from tree genomics, leukemia subtype classification from mixed genomic data, and robust prediction of intensive care unit mortality outcomes from metabolomic profiles. We also provide detailed example analysis on public metabolomic and gene expression datasets. CGBayesNets is implemented in MATLAB and available as MATLAB source code, under an Open Source license and anonymous download at http://www.cgbayesnets.com. PMID:24922310

CGBayesNets: conditional Gaussian Bayesian network learning and inference with mixed discrete and continuous data.

PubMed

McGeachie, Michael J; Chang, Hsun-Hsien; Weiss, Scott T

2014-06-01

Bayesian Networks (BN) have been a popular predictive modeling formalism in bioinformatics, but their application in modern genomics has been slowed by an inability to cleanly handle domains with mixed discrete and continuous variables. Existing free BN software packages either discretize continuous variables, which can lead to information loss, or do not include inference routines, which makes prediction with the BN impossible. We present CGBayesNets, a BN package focused around prediction of a clinical phenotype from mixed discrete and continuous variables, which fills these gaps. CGBayesNets implements Bayesian likelihood and inference algorithms for the conditional Gaussian Bayesian network (CGBNs) formalism, one appropriate for predicting an outcome of interest from, e.g., multimodal genomic data. We provide four different network learning algorithms, each making a different tradeoff between computational cost and network likelihood. CGBayesNets provides a full suite of functions for model exploration and verification, including cross validation, bootstrapping, and AUC manipulation. We highlight several results obtained previously with CGBayesNets, including predictive models of wood properties from tree genomics, leukemia subtype classification from mixed genomic data, and robust prediction of intensive care unit mortality outcomes from metabolomic profiles. We also provide detailed example analysis on public metabolomic and gene expression datasets. CGBayesNets is implemented in MATLAB and available as MATLAB source code, under an Open Source license and anonymous download at http://www.cgbayesnets.com.

Impact of Postoperative Antibiotic Prophylaxis Duration on Surgical Site Infections in Autologous Breast Reconstruction.

PubMed

Drury, Kerry E; Lanier, Steven T; Khavanin, Nima; Hume, Keith M; Gutowski, Karol A; Thornton, Brian P; Hansen, Nora M; Murphy, Robert X; Fine, Neil A; Kim, John Y S

2016-02-01

Although some surgeons prescribe prolonged postoperative antibiotics after autologous breast reconstruction, evidence is lacking to support this practice. We used the Tracking Operations and Outcomes for Plastic Surgeons database to evaluate the association between postoperative antibiotic duration and the rate of surgical site infection (SSI) in autologous breast reconstruction. The intervention of interest for this study was postoperative duration of antibiotic prophylaxis: either discontinued 24 hours after surgery or continued beyond 24 hours. The primary outcome variable of interest for this study was the presence of SSI within 30 days of autologous breast reconstruction. Cohort characteristics and 30-day outcomes were compared using χ² and Fischer exact tests for categorical variables and Student t tests for continuous variables. Multivariate logistic regression was used to control for confounders. A total of 1036 patients met inclusion criteria for our study. Six hundred fifty-nine patients (63.6%) received antibiotics for 24 hours postoperatively, and 377 patients (36.4%) received antibiotics for greater than 24 hours. The rate of SSI did not differ significantly between patients given antibiotics for only 24 hours and those continued on antibiotics beyond the 24-hour postoperative time period (5.01% vs 2.92%, P = 0.109). Furthermore, antibiotic duration was not predictive of SSI in multivariate regression modeling. We did not find a statistically significant difference in the rate of SSI in patients who received 24 hours of postoperative antibiotics compared to those that received antibiotics for greater than 24 hours. These findings held for both purely autologous reconstruction as well as latissimus dorsi reconstruction in conjunction with an implant. Thus, our study does not support continuation of postoperative antibiotics beyond 24 hours after autologous breast reconstruction.

Children who screen positive for autism at 2.5 years and receive early intervention: a prospective naturalistic 2-year outcome study

PubMed Central

Spjut Jansson, Birgitta; Miniscalco, Carmela; Westerlund, Joakim; Kantzer, Anne-Katrin; Fernell, Elisabeth; Gillberg, Christopher

2016-01-01

Background Previous research has stressed the importance of early identification and intervention for children with autism spectrum disorders. Methods Children who had screened positive for autism at the age of 2.5 years in a general population screening and then received a diagnosis of autism spectrum disorder were enrolled in an intervention program provided by Swedish habilitation services. The following interventions were available: a comprehensive intervention based on Applied Behavior Analysis – Intensive Learning (IL) – in two settings, which included home- and preschool-based (IL Regular) and only home-based (IL Modified) and eclectic interventions. Results There was considerable variability in terms of outcome, but intervention group status was not associated with any of the chosen outcome variables. Conclusion The main finding was that the type of intervention was not critical for outcome of adaptive or global functioning. The variability in outcome demonstrates the need for continuous assessments and evaluation of the child’s function and behavior throughout the intervention period. PMID:27621636

The Impact of School Improvement Grants on Achievement: Plans for a National Evaluation Using a Regression Discontinuity Design

ERIC Educational Resources Information Center

Deke, John; Dragoset, Lisa

2015-01-01

Does receipt of School Improvement Grants (SIG) funding to implement a school intervention model have an impact on outcomes for low-performing schools? This study answers this question using a regression discontinuity design (RDD) that exploits cutoff values on the continuous variables used to define SIG eligibility tiers, comparing outcomes in…

Predicting declines in perceived relationship continuity using practice deprivation scores: a longitudinal study in primary care.

PubMed

Levene, Louis S; Baker, Richard; Walker, Nicola; Williams, Christopher; Wilson, Andrew; Bankart, John

2018-06-01

Increased relationship continuity in primary care is associated with better health outcomes, greater patient satisfaction, and fewer hospital admissions. Greater socioeconomic deprivation is associated with lower levels of continuity, as well as poorer health outcomes. To investigate whether deprivation scores predicted variations in the decline over time of patient-perceived relationship continuity of care, after adjustment for practice organisational and population factors. An observational study in 6243 primary care practices with more than one GP, in England, using a longitudinal multilevel linear model, 2012-2017 inclusive. Patient-perceived relationship continuity was calculated using two questions from the GP Patient Survey. The effect of deprivation on the linear slope of continuity over time was modelled, adjusting for nine confounding variables (practice population and organisational factors). Clustering of measurements within general practices was adjusted for by using a random intercepts and random slopes model. Descriptive statistics and univariable analyses were also undertaken. Relationship continuity declined by 27.5% between 2012 and 2017, and at all deprivation levels. Deprivation scores from 2012 did not predict variations in the decline of relationship continuity at practice level, after accounting for the effects of organisational and population confounding variables, which themselves did not predict, or weakly predicted with very small effect sizes, the decline of continuity. Cross-sectionally, continuity and deprivation were negatively correlated within each year. The decline in relationship continuity of care has been marked and widespread. Measures to maximise continuity will need to be feasible for individual practices with diverse population and organisational characteristics. © British Journal of General Practice 2018.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration

PubMed Central

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-01-01

Abstract Background Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. Methods We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Results Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Conclusions Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present. PMID:29088358

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

PubMed

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-04-01

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

A Simulation Study of Categorizing Continuous Exposure Variables Measured with Error in Autism Research: Small Changes with Large Effects.

PubMed

Heavner, Karyn; Burstyn, Igor

2015-08-24

Variation in the odds ratio (OR) resulting from selection of cutoffs for categorizing continuous variables is rarely discussed. We present results for the effect of varying cutoffs used to categorize a mismeasured exposure in a simulated population in the context of autism spectrum disorders research. Simulated cohorts were created with three distinct exposure-outcome curves and three measurement error variances for the exposure. ORs were calculated using logistic regression for 61 cutoffs (mean ± 3 standard deviations) used to dichotomize the observed exposure. ORs were calculated for five categories with a wide range for the cutoffs. For each scenario and cutoff, the OR, sensitivity, and specificity were calculated. The three exposure-outcome relationships had distinctly shaped OR (versus cutoff) curves, but increasing measurement error obscured the shape. At extreme cutoffs, there was non-monotonic oscillation in the ORs that cannot be attributed to "small numbers." Exposure misclassification following categorization of the mismeasured exposure was differential, as predicted by theory. Sensitivity was higher among cases and specificity among controls. Cutoffs chosen for categorizing continuous variables can have profound effects on study results. When measurement error is not too great, the shape of the OR curve may provide insight into the true shape of the exposure-disease relationship.

Cardiorespiratory interaction with continuous positive airway pressure

PubMed Central

Bonafini, Sara; Fava, Cristiano; Steier, Joerg

2018-01-01

The treatment of choice for obstructive sleep apnoea (OSA) is continuous positive airway pressure therapy (CPAP). Since its introduction in clinical practice, CPAP has been used in various clinical conditions with variable and heterogeneous outcomes. In addition to the well-known effects on the upper airway CPAP impacts on intrathoracic pressures, haemodynamics and blood pressure (BP) control. However, short- and long-term effects of CPAP therapy depend on multiple variables which include symptoms, underlying condition, pressure used, treatment acceptance, compliance and usage. CPAP can alter long-term cardiovascular risk in patients with cardiorespiratory conditions. Furthermore, the effect of CPAP on the awake patient differs from the effect on the patients while asleep, and this might contribute to discomfort and removal of the use interface. The purpose of this review is to highlight the physiological impact of CPAP on the cardiorespiratory system, including short-term benefits and long-term outcomes. PMID:29445529

MIMICKING COUNTERFACTUAL OUTCOMES TO ESTIMATE CAUSAL EFFECTS.

PubMed

Lok, Judith J

2017-04-01

In observational studies, treatment may be adapted to covariates at several times without a fixed protocol, in continuous time. Treatment influences covariates, which influence treatment, which influences covariates, and so on. Then even time-dependent Cox-models cannot be used to estimate the net treatment effect. Structural nested models have been applied in this setting. Structural nested models are based on counterfactuals: the outcome a person would have had had treatment been withheld after a certain time. Previous work on continuous-time structural nested models assumes that counterfactuals depend deterministically on observed data, while conjecturing that this assumption can be relaxed. This article proves that one can mimic counterfactuals by constructing random variables, solutions to a differential equation, that have the same distribution as the counterfactuals, even given past observed data. These "mimicking" variables can be used to estimate the parameters of structural nested models without assuming the treatment effect to be deterministic.

Vitamin D levels and their associations with survival and major disease outcomes in a large cohort of patients with chronic graft-vs-host disease

PubMed Central

Katić, Mašenjka; Pirsl, Filip; Steinberg, Seth M.; Dobbin, Marnie; Curtis, Lauren M.; Pulanić, Dražen; Desnica, Lana; Titarenko, Irina; Pavletic, Steven Z.

2016-01-01

Aim To identify the factors associated with vitamin D status in patients with chronic graft-vs-host disease (cGVHD) and evaluate the association between serum vitamin D (25(OH)D) levels and cGVHD characteristics and clinical outcomes defined by the National Institutes of Health (NIH) criteria. Methods 310 cGVHD patients enrolled in the NIH cGVHD natural history study (clinicaltrials.gov: NCT00092235) were analyzed. Univariate analysis and multiple logistic regression were used to determine the associations between various parameters and 25(OH)D levels, dichotomized into categorical variables: ≤20 and >20 ng/mL, and as a continuous parameter. Multiple logistic regression was used to develop a predictive model for low vitamin D. Survival analysis and association between cGVHD outcomes and 25(OH)D as a continuous as well as categorical variable: ≤20 and >20 ng/mL; <50 and ≥50 ng/mL, and among three ordered categories: ≤20, 20-50, and ≥50 ng/mL, was performed. PMID:27374829

Assessment of Scientific Reasoning as an Institutional Outcome

DTIC Science & Technology

2016-04-01

expertise in the outcome domain. Student achievement of the Scientific Reasoning and Principles of Science was assessed in the 2012- 13 academic year by...scientific reasoning assessment. Overall, students were weakest when answering questions related to (a) proportional reasoning , (b) isolation of...variables, and (c) if-then reasoning . These findings are being incorporates into redesign of the core curriculum to enhance continuity among science courses

Extensions of the Johnson-Neyman Technique to Linear Models with Curvilinear Effects: Derivations and Analytical Tools

ERIC Educational Resources Information Center

Miller, Jason W.; Stromeyer, William R.; Schwieterman, Matthew A.

2013-01-01

The past decade has witnessed renewed interest in the use of the Johnson-Neyman (J-N) technique for calculating the regions of significance for the simple slope of a focal predictor on an outcome variable across the range of a second, continuous independent variable. Although tools have been developed to apply this technique to probe 2- and 3-way…

Continuous glucose monitoring to assess the ecologic validity of dietary glycemic index and glycemic load123

PubMed Central

Ebbeling, Cara B; Wadden, Thomas A; Ludwig, David S

2011-01-01

Background: The circumstances under which the glycemic index (GI) and glycemic load (GL) are derived do not reflect real-world eating behavior. Thus, the ecologic validity of these constructs is incompletely known. Objective: This study examined the relation of dietary intake to glycemic response when foods are consumed under free-living conditions. Design: Participants were 26 overweight or obese adults with type 2 diabetes who participated in a randomized trial of lifestyle modification. The current study includes baseline data, before initiation of the intervention. Participants wore a continuous glucose monitor and simultaneously kept a food diary for 3 d. The dietary variables included GI, GL, and intakes of energy, fat, protein, carbohydrate, sugars, and fiber. The glycemic response variables included AUC, mean and SD of continuous glucose monitoring (CGM) values, percentage of CGM values in euglycemic and hyperglycemic ranges, and mean amplitude of glycemic excursions. Relations between daily dietary intake and glycemic outcomes were examined. Results: Data were available from 41 d of monitoring. Partial correlations, controlled for energy intake, indicated that GI or GL was significantly associated with each glycemic response outcome. In multivariate analyses, dietary GI accounted for 10% to 18% of the variance in each glycemic variable, independent of energy and carbohydrate intakes (P < 0.01). Conclusions: The data support the ecologic validity of the GI and GL constructs in free-living obese adults with type 2 diabetes. GI was the strongest and most consistent independent predictor of glycemic stability and variability. PMID:22071699

Cluster analysis and prediction of treatment outcomes for chronic rhinosinusitis.

PubMed

Soler, Zachary M; Hyer, J Madison; Rudmik, Luke; Ramakrishnan, Viswanathan; Smith, Timothy L; Schlosser, Rodney J

2016-04-01

Current clinical classifications of chronic rhinosinusitis (CRS) have weak prognostic utility regarding treatment outcomes. Simplified discriminant analysis based on unsupervised clustering has identified novel phenotypic subgroups of CRS, but prognostic utility is unknown. We sought to determine whether discriminant analysis allows prognostication in patients choosing surgery versus continued medical management. A multi-institutional prospective study of patients with CRS in whom initial medical therapy failed who then self-selected continued medical management or surgical treatment was used to separate patients into 5 clusters based on a previously described discriminant analysis using total Sino-Nasal Outcome Test-22 (SNOT-22) score, age, and missed productivity. Patients completed the SNOT-22 at baseline and for 18 months of follow-up. Baseline demographic and objective measures included olfactory testing, computed tomography, and endoscopy scoring. SNOT-22 outcomes for surgical versus continued medical treatment were compared across clusters. Data were available on 690 patients. Baseline differences in demographics, comorbidities, objective disease measures, and patient-reported outcomes were similar to previous clustering reports. Three of 5 clusters identified by means of discriminant analysis had improved SNOT-22 outcomes with surgical intervention when compared with continued medical management (surgery was a mean of 21.2 points better across these 3 clusters at 6 months, P < .05). These differences were sustained at 18 months of follow-up. Two of 5 clusters had similar outcomes when comparing surgery with continued medical management. A simplified discriminant analysis based on 3 common clinical variables is able to cluster patients and provide prognostic information regarding surgical treatment versus continued medical management in patients with CRS. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Using Electronic Health Record (EHR) “Big Data” to Examine the Influence of Nurse Continuity on a Hospital-Acquired Never Event

PubMed Central

STIFTER, Janet; YAO, Yingwei; LODHI, Muhammad Kamran; LOPEZ, Karen Dunn; KHOKHAR, Ashfaq; WILKIE, Diana J.; KEENAN, Gail M.

2015-01-01

Background There is little research demonstrating the influence of nurse continuity on patient outcomes despite an intuitive belief that continuity of care makes a difference in care outcomes. Objective To examine the influence of nurse continuity (the number of consecutive care days by the same/consistent RN[s]) on the prevention of hospital-acquired pressure ulcers (HAPU). Method A secondary use of data from the Hands on Automated Nursing Data System (HANDS) was performed for this comparative study. The HANDS is a nursing plan of care (POC) “big data” database containing 42,403 episodes documented by 787 nurses, on 9 units, in four hospitals and includes nurse staffing and patient characteristics. Via data mining, we created an analytic dataset of 840 care episodes, 210 with and 630 without HAPUs, matched by nursing unit, patient age, and patient characteristics. Logistic regression analysis determined the influence of nurse continuity and additional nurse-staffing variables on the presence of HAPUs. Results Poor nurse continuity (Continuity Index=.21-.42 [1.0=optimal continuity]) was noted on all nine study units. Nutrition, mobility, perfusion, hydration, and skin problems on admission as well as patient age were associated with HAPUs (p<.001). Controlling for patient characteristics, nurse continuity and the interactions between nurse continuity and other nurse-staffing variables were not significantly associated with HAPU development. Discussion Patient characteristics including nutrition, mobility, and perfusion were associated with HAPUs, but nurse continuity was not. One study implication is that to reduce the incidence of HAPUs the most effective resource utilization might be in the continued development of best practices to address patient characteristics that lead to pressure ulcer vulnerability rather than a focus on nurse staffing. PMID:26325278

Assessment of Program Impact Through First Grade, Volume III: Impact on Parents. An Evaluation of Project Developmental Continuity. Interim Report X.

ERIC Educational Resources Information Center

Morris, Mary; And Others

Third in a series of six, this volume reports findings concerning the impact of Project Developmental Continuity (PDC) on the parents of the evaluation study's cohort of children as well as preliminary findings on the relationship between family characteristics and program outcome variables up to the time the children had completed grade 1. Begun…

Inferior outcomes for black children with high risk acute lymphoblastic leukemia and the impact of socioeconomic variables.

PubMed

Walsh, Alexandra; Chewning, Joseph; Li, Xuelin; Dai, Chen; Whelan, Kimberly; Madan-Swain, Avi; Waterbor, John; Baskin, Monica L; Goldman, Frederick D

2017-02-01

While significant improvements have been made for children with acute lymphoblastic leukemia (ALL) in the United States over the past 20 years, black patients continue to have inferior outcomes. The full impact of socioeconomic variables on outcomes in this minority population is not entirely understood. Disease characteristics, demographic, and socioeconomic status (SES) variables were collected on black (n = 44) and white (n = 178) patients diagnosed at the University of Alabama at Birmingham. Cox proportional hazard regression was used to evaluate the influence of SES and insurance status on survival. As a cohort, 5-year overall survival (OS) was 87% (82-91%), with a median follow-up of 99 months. In univariable analysis, black race was not significantly associated with a higher risk of death or relapse and death. White and black patients with standard-risk leukemia had excellent outcomes, with 97% (91-99%) and 96% (75-99%) 5-year OS, respectively. In contrast, for high-risk disease, white patients had a statistically significant improved 5-year OS rates compared with black patients (79% [68-87%] vs. 52% [28-72%]). Black children were more likely to have public insurance, and, in multivariable analysis, this was associated with a trend toward an improved outcome. Black patients also had poorer census tract-level SES parameters, but these variables were not associated with survival. Our study demonstrates significantly inferior outcomes for black children with high-risk leukemia. These outcome disparities were not related to SES variables, including poverty or private insurance coverage, suggesting the involvement of other factors and highlighting the need for a prospective investigative analysis. © 2016 Wiley Periodicals, Inc.

Online continuing medical education (CME) for GPs: does it work? A systematic review.

PubMed

Thepwongsa, Isaraporn; Kirby, Catherine N; Schattner, Peter; Piterman, Leon

2014-10-01

Numerous studies have assessed the effectiveness of online continuing medical education (CME) designed to improve healthcare professionals' care of patients. The effects of online educational interventions targeted at general practitioners (GP), however, have not been systematically reviewed. A computer search was conducted through seven databases for studies assessing changes in GPs' knowledge and practice, or patient outcomes following an online educational intervention. Eleven studies met the eligibility criteria. Most studies (8/11, 72.7%) found a significant improvement in at least one of the following outcomes: satisfaction, knowledge or practice change. There was little evidence for the impact of online CME on patient outcomes. Variability in study design, characteristics of online and outcome measures limited conclusions on the effects of online CME. Online CME could improve GP satisfaction, knowledge and practices but there are very few well-designed studies that focus on this delivery method of GP education.

Instrumental variables estimation of exposure effects on a time-to-event endpoint using structural cumulative survival models.

PubMed

Martinussen, Torben; Vansteelandt, Stijn; Tchetgen Tchetgen, Eric J; Zucker, David M

2017-12-01

The use of instrumental variables for estimating the effect of an exposure on an outcome is popular in econometrics, and increasingly so in epidemiology. This increasing popularity may be attributed to the natural occurrence of instrumental variables in observational studies that incorporate elements of randomization, either by design or by nature (e.g., random inheritance of genes). Instrumental variables estimation of exposure effects is well established for continuous outcomes and to some extent for binary outcomes. It is, however, largely lacking for time-to-event outcomes because of complications due to censoring and survivorship bias. In this article, we make a novel proposal under a class of structural cumulative survival models which parameterize time-varying effects of a point exposure directly on the scale of the survival function; these models are essentially equivalent with a semi-parametric variant of the instrumental variables additive hazards model. We propose a class of recursive instrumental variable estimators for these exposure effects, and derive their large sample properties along with inferential tools. We examine the performance of the proposed method in simulation studies and illustrate it in a Mendelian randomization study to evaluate the effect of diabetes on mortality using data from the Health and Retirement Study. We further use the proposed method to investigate potential benefit from breast cancer screening on subsequent breast cancer mortality based on the HIP-study. © 2017, The International Biometric Society.

The relationships among nurses' job characteristics and attitudes toward web-based continuing learning.

PubMed

Chiu, Yen-Lin; Tsai, Chin-Chung; Fan Chiang, Chih-Yun

2013-04-01

The purpose of this study was to explore the relationships between job characteristics (job demands, job control and social support) and nurses' attitudes toward web-based continuing learning. A total of 221 in-service nurses from hospitals in Taiwan were surveyed. The Attitudes toward Web-based Continuing Learning Survey (AWCL) was employed as the outcome variables, and the Chinese version Job Characteristic Questionnaire (C-JCQ) was administered to assess the predictors for explaining the nurses' attitudes toward web-based continuing learning. To examine the relationships among these variables, hierarchical regression was conducted. The results of the regression analysis revealed that job control and social support positively associated with nurses' attitudes toward web-based continuing learning. However, the relationship of job demands to such learning was not significant. Moreover, a significant demands×job control interaction was found, but the job demands×social support interaction had no significant relationships with attitudes toward web-based continuing learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficacy of plasma-rich growth factor in the healing of postextraction sockets in patients affected by insulin-dependent diabetes mellitus.

PubMed

Mozzati, Marco; Gallesio, Giorgia; di Romana, Sara; Bergamasco, Laura; Pol, Renato

2014-03-01

To evaluate the efficacy of plasma-rich growth factor (PRGF) in improving socket healing after tooth extraction in diabetic patients. This was a split-mouth study in which each patient also served as the control: the study socket was treated with PRGF, whereas the control socket underwent natural healing. The outcome variables were the Healing Index, residual socket volume, visual analog scale score, postsurgical complications, and outcome of a patient questionnaire. The investigation considered the impact of hyperglycemia, glycated hemoglobin, End Organ Disease Score, and smoking habits. Follow-up included 4 postextraction checkups over a 21-day period. Pairs of correlated continuous variables were analyzed with the Wilcoxon test, independent continuous variables with the Mann-Whitney test, and categorical variables with the χ(2) test or Fisher test. From January 2012 to December 2012, 34 patients affected by insulin-dependent diabetes mellitus underwent contemporary bilateral extractions of homologous teeth. The treatment-versus-control postoperative comparison showed that PRGF resulted in significantly smaller residual socket volumes and better Healing Indices from days 3 to 14. The patients' questionnaire outcomes were unanimously in favor of PRGF treatment. The small sample of patients with glycemia values of at least 240 mg/dL showed worse Healing Index and minor socket decreases. PRGF application after extraction improved the healing process in diabetic patients by accelerating socket closure (epithelialization) and tissue maturation, proving the association between PRGF use and improved wound healing in diabetic patients. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Nasal Jet-CPAP (variable flow) versus Bubble-CPAP in preterm infants with respiratory distress: an open label, randomized controlled trial.

PubMed

Bhatti, A; Khan, J; Murki, S; Sundaram, V; Saini, S S; Kumar, P

2015-11-01

To compare the failure rates between Jet continuous positive airway pressure device (J-CPAP-variable flow) and Bubble continuous positive airway device (B-CPAP) in preterm infants with respiratory distress. Preterm newborns <34 weeks gestation with onset of respiratory distress within 6 h of life were randomized to receive J-CPAP (a variable flow device) or B-CPAP (continuous flow device). A standardized protocol was followed for titration, weaning and removal of CPAP. Pressure was monitored close to the nares in both the devices every 6 hours and settings were adjusted to provide desired CPAP. The primary outcome was CPAP failure rate within 72 h of life. Secondary outcomes were CPAP failure within 7 days of life, need for surfactant post-randomization, time to CPAP failure, duration of CPAP and complications of prematurity. An intention to treat analysis was done. One-hundred seventy neonates were randomized, 80 to J-CPAP and 90 to B-CPAP. CPAP failure rates within 72 h were similar in infants who received J-CPAP and in those who received B-CPAP (29 versus 21%; relative risks 1.4 (0.8 to 2.3), P=0.25). Mean (95% confidence intervals) time to CPAP failure was 59 h (54 to 64) in the Jet CPAP group in comparison with 65 h (62 to 68) in the Bubble CPAP group (log rank P=0.19). All other secondary outcomes were similar between the two groups. In preterm infants with respiratory distress starting within 6 h of life, CPAP failure rates were similar with Jet CPAP and Bubble CPAP.

A randomised controlled trial of flow driver and bubble continuous positive airway pressure in preterm infants in a resource-limited setting.

PubMed

Mazmanyan, P; Mellor, K; Doré, C J; Modi, N

2016-01-01

The variable-flow flow driver (FD; EME) and continuous-flow bubble (Fisher-Paykel) continuous positive airway pressure (CPAP) systems are widely used. As these differ in cost and technical requirements, determining comparative efficacy is important particularly where resources are limited. We performed a randomised, controlled, equivalence trial of CPAP systems. We specified the margin of equivalence as 2 days. We analysed binary variables by logistical regression adjusted for gestation, and log transformed continuous variables by multiple linear regression adjusted for gestation, sex and antenatal steroids. A neonatal unit with no blood gas analyser or surfactant availability and limited X-ray and laboratory facilities Neonates <37 weeks of gestation. We provided CPAP at delivery followed by randomisation to FD or bubble (B). Primary outcome included total days receiving CPAP; secondary outcomes included days receiving CPAP, supplemental oxygen, ventilation, death, pneumothorax and nasal excoriation. We randomised 125 infants (B 66, FD 59). Differences in infant outcomes on B and FD were not statistically significant. The median (range) for CPAP days for survivors was B 0.8 (0.04 to 17.5), FD 0.5 (0.04 to 5.3). B:FD (95% CI) ratios were CPAP days 1.3 (0.9 to 2.1), CPAP plus supplementary oxygen days 1.2 (0.7 to 1.9). B:FD (95% CI) ORs were death 2.3 (0.2 to 28), ventilation 2.1 (0.5 to 9), nasal excoriation 1.2 (0.2 to 8) and pneumothorax 2.4 (0.2 to 26). In a resource-limited setting we found B CPAP equivalent to FD CPAP in the total number of days receiving CPAP within a margin of 2 days. ISRCTN22578364. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Brain Natriuretic Peptide Is a Powerful Predictor of Outcome in Stroke Patients with Atrial Fibrillation

PubMed Central

Maruyama, Kenji; Uchiyama, Shinichiro; Shiga, Tsuyoshi; Iijima, Mutsumi; Ishizuka, Kentaro; Hoshino, Takao; Kitagawa, Kazuo

2017-01-01

Background Since stroke patients with nonvalvular atrial fibrillation (NVAF) have poor outcomes in general, the prediction of outcomes following discharge is of utmost concern for these patients. We previously reported that brain natriuretic peptide (BNP) levels were significantly higher in NVAF patients with larger infarcts, higher modified Rankin Scale (mRS) score, and higher CHADS2 score. In the present study, we evaluated an array of variables, including BNP, in order to determine significant predictors for functional outcome in patients with NVAF after acute ischemic stroke (AIS). Methods A total of 615 consecutive patients with AIS within 48 h of symptom onset, admitted to our hospital between April 2010 and October 2015, were retrospectively searched. Among these patients, we enrolled consecutive patients with NVAF. We evaluated the mRS score 3 months after onset of stroke and investigated associations between mRS score and the following clinical and echocardiographic variables. Categorical variables included male sex, current smoking, alcohol intake, hypertension, diabetes mellitus, dyslipidemia, coronary artery disease, peripheral artery disease, use of antiplatelet drugs, anticoagulants, or tissue plasminogen activator (tPA), and infarct size. Continuous variables included age, systolic blood pressure (SBP), diastolic blood pressure, hemoglobin, creatinine, D-dimer, brain natriuretic peptide (BNP), left atrial diameter, left ventricular ejection fraction (EF), and early mitral inflow velocity/diastolic mitral annular velocity (E/e’). We also analyzed the association of prestroke CHADS2, CHA2DS2-VASc, and R2CHADS2 scores, and National Institutes of Health Stroke Scale (NIHSS) score on admission with mRS score 3 months after the onset of stroke. Patients were classified into 2 groups according to mRS score: an mRS score ≤2 was defined as good outcome, an mRS score ≥3 was defined as poor outcome. To clarify the correlations between categorical or continuous variables and mRS score, uni- and multivariate logistic regression models using the stepwise variable selection method were applied. Results Among 157 patients with NVAF after AIS, 63.7% were male and the mean age was 75.9 years. In univariate regression analysis, poor outcome (mRS score ≥3) was associated with use of tPA, infarct size, age, SBP, BNP, EF, and NIHSS score. In multivariate regression analysis, BNP levels (odds ratio [OR] 6.40; 95% confidence interval [CI] 1.26–32.43; p = 0.0235) and NIHSS score (OR 2.87; 95% CI 1.84–4.47; p < 0.001) were significantly associated with poor outcome (mRS score ≥3) after adjusting for use of tPA, infarct size, age, BNP, EF, and NIHSS score. Conclusions Apart from NIHSS score, BNP was a very useful predictor for long-term outcomes of patients with NVAF after AIS. PMID:28253498

A Lack of Continuity in Education, Training, and Practice Violates the "Do No Harm" Principle.

PubMed

Englander, Robert; Carraccio, Carol

2018-03-01

The paradigm shift to competency-based medical education (CBME) is under way, but incomplete implementation is blunting the potential impact on learning and patient outcomes. The fundamental principles of CBME call for standardizing outcomes addressing population health needs, then allowing time-variable progression to achieving them. Operationalizing CBME principles requires continuity within and across phases of the education, training, and practice continuum. However, the piecemeal origin of the phases of the "continuum" has resulted in a sequence of undergraduate to graduate medical education to practice that may be continuous temporally but bears none of the integration of a true continuum.With these timed interruptions during phase transitions, learning is not reinforced because of a failure to integrate experiences. Brief block rotations for learners and ever-shorter supervisory assignments for faculty preclude the development of relationships. Without these relationships, feedback falls on deaf ears. Block rotations also disrupt learners' relationships with patients. The harms resulting from such a system include decreases in patient satisfaction with their care and learner satisfaction with their work. Learners in this block system also demonstrate an erosion of empathy compared with those in innovative longitudinal training models. In addition, higher patient mortality during intern transitions has been demonstrated.The current medical education system is violating the first principle of medicine: "Do no harm." Full implementation of competency-based, time-variable education and training, with fixed outcomes aligned with population health needs, continuity in learning and relationships, and support from a developmental program of assessment, holds great potential to stop this harm.

Quantitative EEG Metrics Differ Between Outcome Groups and Change Over the First 72 h in Comatose Cardiac Arrest Patients.

PubMed

Wiley, Sara Leingang; Razavi, Babak; Krishnamohan, Prashanth; Mlynash, Michael; Eyngorn, Irina; Meador, Kimford J; Hirsch, Karen G

2018-02-01

Forty to sixty-six percent of patients resuscitated from cardiac arrest remain comatose, and historic outcome predictors are unreliable. Quantitative spectral analysis of continuous electroencephalography (cEEG) may differ between patients with good and poor outcomes. Consecutive patients with post-cardiac arrest hypoxic-ischemic coma undergoing cEEG were enrolled. Spectral analysis was conducted on artifact-free contiguous 5-min cEEG epochs from each hour. Whole band (1-30 Hz), delta (δ, 1-4 Hz), theta (θ, 4-8 Hz), alpha (α, 8-13 Hz), beta (β, 13-30 Hz), α/δ power ratio, percent suppression, and variability were calculated and correlated with outcome. Graphical patterns of quantitative EEG (qEEG) were described and categorized as correlating with outcome. Clinical outcome was dichotomized, with good neurologic outcome being consciousness recovery. Ten subjects with a mean age = 50 yrs (range = 18-65) were analyzed. There were significant differences in total power (3.50 [3.30-4.06] vs. 0.68 [0.52-1.02], p = 0.01), alpha power (1.39 [0.66-1.79] vs 0.27 [0.17-0.48], p < 0.05), delta power (2.78 [2.21-3.01] vs 0.55 [0.38-0.83], p = 0.01), percent suppression (0.66 [0.02-2.42] vs 73.4 [48.0-97.5], p = 0.01), and multiple measures of variability between good and poor outcome patients (all values median [IQR], good vs. poor). qEEG patterns with high or increasing power or large power variability were associated with good outcome (n = 6). Patterns with consistently low or decreasing power or minimal power variability were associated with poor outcome (n = 4). These preliminary results suggest qEEG metrics correlate with outcome. In some patients, qEEG patterns change over the first three days post-arrest.

Venovenous extracorporeal membrane oxygenation for ARDS: outcome analysis of a Croatian referral center for respiratory ECMO.

PubMed

Kutleša, Marko; Novokmet, Anđa; Josipović Mraović, Renata; Baršić, Bruno

2017-07-01

The use of venovenous extracorporeal membrane oxygenation (VV-ECMO) as a rescue therapy in severe acute respiratory distress syndrome (ARDS) has become well established; however, the affirmation of evidence on VV-ECMO application and the analysis of patient outcomes after VV-ECMO treatment for ARDS continues. The aim of the study is to identify variables that affected the outcome of patients treated with VV-ECMO for severe ARDS outside a major ECMO center. The study included adult patients with severe ARDS treated with ECMO at a tertiary care hospital in Zagreb, Croatia between October 2009 and July 2014. Patients were recruited from a prospective database. The study enrolled 40 patients, 20 of whom had H1N1-induced ARDS. The hospital mortality was 38%. The difference in mortality and long-term outcome in H1N1-induced ARDS as compared to non-H1N1-induced ARDS was not significant. Variables associated with mortality included immunosuppression, shock at time of admission, acute renal failure, occurrence of heparin-induced thrombocytopenia antibodies, nosocomial sepsis and duration of ECMO. The results of our study indicate that ECMO use in severe ARDS is feasible with low mortality and identify or assert the variables associated with adverse outcomes.

Prognostic factors of a favorable outcome following a supervised exercise program for soldiers with sub-acute and chronic low back pain.

PubMed

Perron, Marc; Gendron, Chantal; Langevin, Pierre; Leblond, Jean; Roos, Marianne; Roy, Jean-Sébastien

2018-04-02

Low back pain (LBP) encompasses heterogeneous patients unlikely to respond to a unique treatment. Identifying sub-groups of LBP may help to improve treatment outcomes. This is a hypothesis-setting study designed to create a clinical prediction rule (CPR) that will predict favorable outcomes in soldiers with sub-acute and chronic LBP participating in a multi-station exercise program. Military members with LBP participated in a supervised program comprising 7 stations each consisting of exercises of increasing difficulty. Demographic, impairment and disability data were collected at baseline. The modified Oswestry Disability Index (ODI) was administered at baseline and following the 6-week program. An improvement of 50% in the initial ODI score was considered the reference standard to determine a favorable outcome. Univariate associations with favorable outcome were tested using chi-square or paired t-tests. Variables that showed between-group (favorable/unfavorable) differences were entered into a logistic regression after determining the sampling adequacy. Finally, continuous variables were dichotomized and the sensitivity, specificity and positive and negative likelihood ratios were determined for the model and for each variable. A sample of 85 participants was included in analyses. Five variables contributed to prediction of a favorable outcome: no pain in lying down (p = 0.017), no use of antidepressants (p = 0.061), FABQ work score < 22.5 (p = 0.061), fewer than 5 physiotherapy sessions before entering the program (p = 0.144) and less than 6 months' work restriction (p = 0.161). This model yielded a sensitivity of 0.78, specificity of 0.80, LR+ of 3.88, and LR- of 0.28. A 77.5% probability of favorable outcome can be predicted by the presence of more than three of the five variables, while an 80% probability of unfavorable outcome can be expected if only three or fewer variables are present. The use of prognostic factors may guide clinicians in identifying soldiers with LBP most likely to have a favorable outcome. Further validation studies are needed to determine if the variables identified in our study are treatment effect modifiers that can predict success following participation in the multi-station exercise program. ClinicalTrials.gov Identifier: NCT03464877 registered retrospectively on 14 March 2018.

Testing concordance of instrumental variable effects in generalized linear models with application to Mendelian randomization

PubMed Central

Dai, James Y.; Chan, Kwun Chuen Gary; Hsu, Li

2014-01-01

Instrumental variable regression is one way to overcome unmeasured confounding and estimate causal effect in observational studies. Built on structural mean models, there has been considerale work recently developed for consistent estimation of causal relative risk and causal odds ratio. Such models can sometimes suffer from identification issues for weak instruments. This hampered the applicability of Mendelian randomization analysis in genetic epidemiology. When there are multiple genetic variants available as instrumental variables, and causal effect is defined in a generalized linear model in the presence of unmeasured confounders, we propose to test concordance between instrumental variable effects on the intermediate exposure and instrumental variable effects on the disease outcome, as a means to test the causal effect. We show that a class of generalized least squares estimators provide valid and consistent tests of causality. For causal effect of a continuous exposure on a dichotomous outcome in logistic models, the proposed estimators are shown to be asymptotically conservative. When the disease outcome is rare, such estimators are consistent due to the log-linear approximation of the logistic function. Optimality of such estimators relative to the well-known two-stage least squares estimator and the double-logistic structural mean model is further discussed. PMID:24863158

Dose response explorer: an integrated open-source tool for exploring and modelling radiotherapy dose volume outcome relationships

NASA Astrophysics Data System (ADS)

El Naqa, I.; Suneja, G.; Lindsay, P. E.; Hope, A. J.; Alaly, J. R.; Vicic, M.; Bradley, J. D.; Apte, A.; Deasy, J. O.

2006-11-01

Radiotherapy treatment outcome models are a complicated function of treatment, clinical and biological factors. Our objective is to provide clinicians and scientists with an accurate, flexible and user-friendly software tool to explore radiotherapy outcomes data and build statistical tumour control or normal tissue complications models. The software tool, called the dose response explorer system (DREES), is based on Matlab, and uses a named-field structure array data type. DREES/Matlab in combination with another open-source tool (CERR) provides an environment for analysing treatment outcomes. DREES provides many radiotherapy outcome modelling features, including (1) fitting of analytical normal tissue complication probability (NTCP) and tumour control probability (TCP) models, (2) combined modelling of multiple dose-volume variables (e.g., mean dose, max dose, etc) and clinical factors (age, gender, stage, etc) using multi-term regression modelling, (3) manual or automated selection of logistic or actuarial model variables using bootstrap statistical resampling, (4) estimation of uncertainty in model parameters, (5) performance assessment of univariate and multivariate analyses using Spearman's rank correlation and chi-square statistics, boxplots, nomograms, Kaplan-Meier survival plots, and receiver operating characteristics curves, and (6) graphical capabilities to visualize NTCP or TCP prediction versus selected variable models using various plots. DREES provides clinical researchers with a tool customized for radiotherapy outcome modelling. DREES is freely distributed. We expect to continue developing DREES based on user feedback.

Nutrition as an important mediator of the impact of background variables on outcome in middle childhood

PubMed Central

Kitsao-Wekulo, Patricia; Holding, Penny; Taylor, H. Gerry; Abubakar, Amina; Kvalsvig, Jane; Connolly, Kevin

2013-01-01

Adequate nutrition is fundamental to the development of a child's full potential. However, the extent to which malnutrition affects developmental and cognitive outcomes in the midst of co-occurring risk factors remains largely understudied. We sought to establish if the effects of nutritional status varied according to diverse background characteristics as well as to compare the relative strength of the effects of poor nutritional status on language skills, motor abilities, and cognitive functioning at school age. This cross-sectional study was conducted among school-age boys and girls resident in Kilifi District in Kenya. We hypothesized that the effects of area of residence, school attendance, household wealth, age and gender on child outcomes are experienced directly and indirectly through child nutritional status. The use of structural equation modeling (SEM) allowed the disaggregation of the total effect of the explanatory variables into direct effects (effects that go directly from one variable to another) and indirect effects. Each of the models tested for the four child outcomes had a good fit. However, the effects on verbal memory apart from being weaker than for the other outcomes, were not mediated through nutritional status. School attendance was the most influential predictor of nutritional status and child outcomes. The estimated models demonstrated the continued importance of child nutritional status at school-age. PMID:24298246

Effects of Achievement Tendencies and Competitive Outcomes on Performance.

ERIC Educational Resources Information Center

Grove, J. Robert; Pargman, David

A study examined cognitive and behavioral consequences of continuous success or failure in a competitive situation involving 40 undergraduate males. Three performance variables were selected for examination: expectancies for success, amount of self-motivated practice, and performance quality. Subjects were informed that they would be competing…

Exposure and response prevention process predicts treatment outcome in youth with OCD.

PubMed

Kircanski, Katharina; Peris, Tara S

2015-04-01

Recent research on the treatment of adults with anxiety disorders suggests that aspects of the in-session exposure therapy process are relevant to clinical outcomes. However, few comprehensive studies have been conducted with children and adolescents. In the present study, 35 youth diagnosed with primary obsessive-compulsive disorder (OCD; M age = 12.9 years, 49% male, 63% Caucasian) completed 12 sessions of exposure and response prevention (ERP) in one of two treatment conditions as part of a pilot randomized controlled testing of a family focused intervention for OCD. Key exposure process variables, including youth self-reported distress during ERP and the quantity and quality of ERP completed, were computed. These variables were examined as predictors of treatment outcomes assessed at mid-treatment, post-treatment, and three-month follow-up, partialing treatment condition. In general, greater variability of distress during ERP and completing a greater proportion of combined exposures (i.e., exposures targeting more than one OC symptom at once) were predictive of better outcomes. Conversely, greater distress at the end of treatment was generally predictive of poorer outcomes. Finally, several variables, including within- and between-session decreases in distress during ERP, were not consistently predictive of outcomes. Findings signal potentially important facets of exposure for youth with OCD and have implications for treatment. A number of results also parallel recent findings in the adult literature, suggesting that there may be some continuity in exposure processes from child to adult development. Future work should examine additional measures of exposure process, such as psychophysiological arousal during exposure, in youth.

Perioperative Near-Infrared Spectroscopy Monitoring in Neonates With Congenital Heart Disease: Relationship of Cerebral Tissue Oxygenation Index Variability With Neurodevelopmental Outcome.

PubMed

Spaeder, Michael C; Klugman, Darren; Skurow-Todd, Kami; Glass, Penny; Jonas, Richard A; Donofrio, Mary T

2017-03-01

To evaluate the value of perioperative cerebral near-infrared spectroscopy monitoring using variability analysis in the prediction of neurodevelopmental outcomes in neonates undergoing surgery for congenital heart disease. Retrospective cohort study. Urban, academic, tertiary-care children's hospital. Neonates undergoing surgery with cardiopulmonary bypass for congenital heart disease. Perioperative monitoring of continuous cerebral tissue oxygenation index by near-infrared spectroscopy and subsequent neurodevelopmental testing at 6, 15, and 21 months of age. We developed a new measure, cerebral tissue oxygenation index variability, using the root mean of successive squared differences of averaged 1-minute cerebral tissue oxygenation index values for both the intraoperative and first 24-hours postoperative phases of monitoring. There were 62 neonates who underwent cerebral tissue oxygenation index monitoring during surgery for congenital heart disease and 44 underwent subsequent neurodevelopmental testing (12 did not survive until testing and six were lost to follow-up). Among the 44 monitored patients who underwent neurodevelopmental testing, 20 (45%) had abnormal neurodevelopmental indices. Patients with abnormal neurodevelopmental indices had lower postoperative cerebral tissue oxygenation index variability when compared with patients with normal indices (p = 0.01). Adjusting for class of congenital heart disease and duration of deep hypothermic circulatory arrest, lower postoperative cerebral tissue oxygenation index variability was associated with poor neurodevelopmental outcome (p = 0.02). We found reduced postoperative cerebral tissue oxygenation index variability in neonatal survivors of congenital heart disease surgery with poor neurodevelopmental outcomes. We hypothesize that reduced cerebral tissue oxygenation index variability may be a surrogate for impaired cerebral metabolic autoregulation in the immediate postoperative period. Further research is needed to investigate clinical implications of this finding and opportunities for using this measure to drive therapeutic interventions.

Dichotomisation using a distributional approach when the outcome is skewed.

PubMed

Sauzet, Odile; Ofuya, Mercy; Peacock, Janet L

2015-04-24

Dichotomisation of continuous outcomes has been rightly criticised by statisticians because of the loss of information incurred. However to communicate a comparison of risks, dichotomised outcomes may be necessary. Peacock et al. developed a distributional approach to the dichotomisation of normally distributed outcomes allowing the presentation of a comparison of proportions with a measure of precision which reflects the comparison of means. Many common health outcomes are skewed so that the distributional method for the dichotomisation of continuous outcomes may not apply. We present a methodology to obtain dichotomised outcomes for skewed variables illustrated with data from several observational studies. We also report the results of a simulation study which tests the robustness of the method to deviation from normality and assess the validity of the newly developed method. The review showed that the pattern of dichotomisation was varying between outcomes. Birthweight, Blood pressure and BMI can either be transformed to normal so that normal distributional estimates for a comparison of proportions can be obtained or better, the skew-normal method can be used. For gestational age, no satisfactory transformation is available and only the skew-normal method is reliable. The normal distributional method is reliable also when there are small deviations from normality. The distributional method with its applicability for common skewed data allows researchers to provide both continuous and dichotomised estimates without losing information or precision. This will have the effect of providing a practical understanding of the difference in means in terms of proportions.

Intervention Adherence for Research and Practice: Necessity or Triage Outcome?

ERIC Educational Resources Information Center

Barnett, David; Hawkins, Renee; Lentz, F. Edward, Jr.

2011-01-01

Intervention integrity or adherence describes qualities of carrying out an intervention plan and in research is fundamentally linked to experimental validity questions addressed by measurement of independent and dependent variables. Integrity has been well described in conceptual writing but has been a continuing thorny subject in research and…

Patient Characteristics and Variability in Adherence and Competence in Cognitive-Behavioral Therapy for Panic Disorder

ERIC Educational Resources Information Center

Boswell, James F.; Gallagher, Matthew W.; Sauer-Zavala, Shannon E.; Bullis, Jacqueline; Gorman, Jack M.; Shear, M. Katherine; Woods, Scott; Barlow, David H.

2013-01-01

Although associations with outcome have been inconsistent, therapist adherence and competence continues to garner attention, particularly within the context of increasing interest in the dissemination, implementation, and sustainability of evidence-based treatments. To date, research on therapist adherence and competence has focused on average…

Modelling of binary logistic regression for obesity among secondary students in a rural area of Kedah

NASA Astrophysics Data System (ADS)

Kamaruddin, Ainur Amira; Ali, Zalila; Noor, Norlida Mohd.; Baharum, Adam; Ahmad, Wan Muhamad Amir W.

2014-07-01

Logistic regression analysis examines the influence of various factors on a dichotomous outcome by estimating the probability of the event's occurrence. Logistic regression, also called a logit model, is a statistical procedure used to model dichotomous outcomes. In the logit model the log odds of the dichotomous outcome is modeled as a linear combination of the predictor variables. The log odds ratio in logistic regression provides a description of the probabilistic relationship of the variables and the outcome. In conducting logistic regression, selection procedures are used in selecting important predictor variables, diagnostics are used to check that assumptions are valid which include independence of errors, linearity in the logit for continuous variables, absence of multicollinearity, and lack of strongly influential outliers and a test statistic is calculated to determine the aptness of the model. This study used the binary logistic regression model to investigate overweight and obesity among rural secondary school students on the basis of their demographics profile, medical history, diet and lifestyle. The results indicate that overweight and obesity of students are influenced by obesity in family and the interaction between a student's ethnicity and routine meals intake. The odds of a student being overweight and obese are higher for a student having a family history of obesity and for a non-Malay student who frequently takes routine meals as compared to a Malay student.

Year of treatment as independent predictor of relapse-free survival in patients with localized prostate cancer treated with definitive radiotherapy in the PSA era.

PubMed

Kupelian, Patrick; Thames, Howard; Levy, Larry; Horwitz, Eric; Martinez, Alvaro; Michalski, Jeff; Pisansky, Thomas; Sandler, Howard; Shipley, William; Zelefsky, Michael; Zietman, Anthony; Kuban, Deborah

2005-11-01

To study the use of the year of therapy as an independent predictor of outcomes, serving as a proxy for time-related changes in therapy and tumor factors in the treatment of prostate cancer. Accounting for these changes would facilitate the retrospective comparison of outcomes for patients treated in different periods. Nine institutions combined data on 4,537 patients with Stages T1 and T2 adenocarcinoma of the prostate who had a pretherapy prostate-specific antigen (PSA) level and biopsy Gleason score, and who had received > or = 60 Gy external beam radiotherapy without neoadjuvant androgen deprivation or planned adjuvant androgen deprivation. All patients were treated between 1986 and 1995. Two groups were defined: those treated before 1993 (Yr < or = 92) vs. 1993 and after (Yr > or = 93). Patients treated before 1993 had their follow-up truncated to make the follow-up time similar to that for patients treated in 1993 and after. Therefore, the median follow-up time was 6.0 years for both groups (Yr < or = 92 and Yr > or = 93). Two separate biochemical failure endpoints were used. Definition A consisted of the American Society for Therapeutic Radiology Oncology endpoint (three PSA rises backdated, local failure, distant failure, or hormonal therapy). Definition B consisted of PSA level greater than the current nadir plus two, local failure, distant failure, or hormonal therapy administered. Multivariate analyses for factors affecting PSA disease-free survival (PSA-DFS) rates using both endpoints were performed for all cases using the following variables: T stage (T1b, T1c, T2a vs. T2b, T2c), pretreatment PSA (continuous variable), biopsy Gleason score (continuous variable), radiation dose (continuous variable), and year of treatment (continuous variable). The year variable (defined as the current year minus 1960) ranged from 26 to 35. To evaluate the effect of radiation dose, the multivariate analyses were repeated with the 3,897 cases who had received < 72 Gy using the same variables except for radiation dose. For all 4,537 patients, the 5- and 8-year PSA-DFS estimate using definition A (ASTRO consensus definition) was 60% and 55%, respectively. The 8-year PSA-DFS estimate for Yr < 93 vs. Yr > or = 93 was 52% vs. 57%, respectively (p < 0.001). In the subgroup of patients receiving < 72 Gy, the 8-year PSA-DFS estimate for Yr < 93 vs. Yr > or = 93 was 52% and 55%, respectively (p = 0.004). The differences in PSA-DFS rates in the different subgroups were similar when definition B was used. The multivariate analyses for all 4,537 cases with either PSA-DFS definition revealed T stage (p < 0.001), pretherapy PSA level (p < 0.001), Gleason score (p < 0.001), radiation dose (p < 0.001), and year of treatment (p < 0.001) to be independent predictors of outcomes. The multivariate analyses restricted to the 3,897 cases receiving < 72 Gy still revealed year of treatment to be an independent predictor of outcomes (p < 0.001), in addition to T stage (p < 0.001), pretherapy PSA level (p < 0.001), and Gleason score (p < 0.001). Independent of tumor stage, radiation dose, failure definition, and follow-up parameters, the year in which RT was performed was an independent predictor of outcomes. These findings indicate a more favorable presentation of localized prostate cancer in current years that is not necessarily reflected in the patients' PSA levels or Gleason scores. This phenomenon is probably related to a combination of factors, such as screening, increased patient awareness leading to earlier biopsies and earlier diagnosis, more aggressive pretherapy staging, and unrecognized improvements in therapy, but perhaps also to changing tumor biology. Outcomes predictions should be based on contemporaneous series. Alternatively, the year of therapy could be incorporated as a variable in outcomes analyses of localized prostate cancer patients treated in different periods within the PSA era.

Introduction to the use of regression models in epidemiology.

PubMed

Bender, Ralf

2009-01-01

Regression modeling is one of the most important statistical techniques used in analytical epidemiology. By means of regression models the effect of one or several explanatory variables (e.g., exposures, subject characteristics, risk factors) on a response variable such as mortality or cancer can be investigated. From multiple regression models, adjusted effect estimates can be obtained that take the effect of potential confounders into account. Regression methods can be applied in all epidemiologic study designs so that they represent a universal tool for data analysis in epidemiology. Different kinds of regression models have been developed in dependence on the measurement scale of the response variable and the study design. The most important methods are linear regression for continuous outcomes, logistic regression for binary outcomes, Cox regression for time-to-event data, and Poisson regression for frequencies and rates. This chapter provides a nontechnical introduction to these regression models with illustrating examples from cancer research.

Sibling dilution hypothesis: a regression surface analysis.

PubMed

Marjoribanks, K

2001-08-01

This study examined relationships between sibship size (the number of children in a family), birth order, and measures of academic performance, academic self-concept, and educational aspirations at different levels of family educational resources. As part of a national longitudinal study of Australian secondary school students data were collected from 2,530 boys and 2,450 girls in Years 9 and 10. Regression surfaces were constructed from models that included terms to account for linear, interaction, and curvilinear associations among the variables. Analysis suggests the general propositions (a) family educational resources have significant associations with children's school-related outcomes at different levels of sibling variables, the relationships for girls being curvilinear, and (b) sibling variables continue to have small significant associations with affective and cognitive outcomes, after taking into account variations in family educational resources. That is, the investigation provides only partial support for the sibling dilution hypothesis.

Correlation and simple linear regression.

PubMed

Zou, Kelly H; Tuncali, Kemal; Silverman, Stuart G

2003-06-01

In this tutorial article, the concepts of correlation and regression are reviewed and demonstrated. The authors review and compare two correlation coefficients, the Pearson correlation coefficient and the Spearman rho, for measuring linear and nonlinear relationships between two continuous variables. In the case of measuring the linear relationship between a predictor and an outcome variable, simple linear regression analysis is conducted. These statistical concepts are illustrated by using a data set from published literature to assess a computed tomography-guided interventional technique. These statistical methods are important for exploring the relationships between variables and can be applied to many radiologic studies.

Shape of Thyroid Cartilage Influences Outcome of Montgomery Medialization Thyroplasty: A Gender Issue.

PubMed

Desuter, Gauthier; Henrard, Sylvie; Van Lith-Bijl, Julie T; Amory, Avigaëlle; Duprez, Thierry; van Benthem, Peter Paul; Sjögren, Elisabeth

2017-03-01

This study aimed to determine whether the shape of the thyroid cartilage and gender influence voice outcomes after a Montgomery thyroplasty implant system (MTIS). A retrospective cohort study was performed on 20 consecutive patients who underwent MTIS. Voice outcome variables were the relative decrease in Voice Handicap Index (%) and the absolute increase in maximum phonation time (MPT) (in seconds). Material variables were the angle between the thyroid cartilage laminae (α-angle), the size of the prosthesis, and a combination of both (the α-ratio). Continuous variables were analyzed using medians and were compared between groups using the Mann-Whitney U test. Factors associated with the outcome variables were assessed by multivariable linear regression. A Pearson coefficient was calculated between material variables. The absolute increase in MPT between the pre- and postoperative period was significantly different between men and women, with a median absolute increase of 11.0 seconds for men and of 1.3 seconds for women (P < 0.001). A strong inverse correlation between the α-ratio and the absolute increase in MPT is observed in all patients, with a Pearson correlation coefficient R = -0.769 (P < 0.001). No factors were significantly associated with the relative Voice Handicap Index decrease in univariable or multivariable analyses. A better Pearson coefficient between the α-angle and the prosthesis size was found for females (0.8 vs 0.71). The MTIS is a good thyroplasty modality for male patients, but inadequate design of MTIS female implants leads to poor MPT outcomes. This represents a gender issue that needs to be further studied and eventually tackled. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Why we should use simpler models if the data allow this: relevance for ANOVA designs in experimental biology.

PubMed

Lazic, Stanley E

2008-07-21

Analysis of variance (ANOVA) is a common statistical technique in physiological research, and often one or more of the independent/predictor variables such as dose, time, or age, can be treated as a continuous, rather than a categorical variable during analysis - even if subjects were randomly assigned to treatment groups. While this is not common, there are a number of advantages of such an approach, including greater statistical power due to increased precision, a simpler and more informative interpretation of the results, greater parsimony, and transformation of the predictor variable is possible. An example is given from an experiment where rats were randomly assigned to receive either 0, 60, 180, or 240 mg/L of fluoxetine in their drinking water, with performance on the forced swim test as the outcome measure. Dose was treated as either a categorical or continuous variable during analysis, with the latter analysis leading to a more powerful test (p = 0.021 vs. p = 0.159). This will be true in general, and the reasons for this are discussed. There are many advantages to treating variables as continuous numeric variables if the data allow this, and this should be employed more often in experimental biology. Failure to use the optimal analysis runs the risk of missing significant effects or relationships.

Continuous-Variable Instantaneous Quantum Computing is Hard to Sample.

PubMed

Douce, T; Markham, D; Kashefi, E; Diamanti, E; Coudreau, T; Milman, P; van Loock, P; Ferrini, G

2017-02-17

Instantaneous quantum computing is a subuniversal quantum complexity class, whose circuits have proven to be hard to simulate classically in the discrete-variable realm. We extend this proof to the continuous-variable (CV) domain by using squeezed states and homodyne detection, and by exploring the properties of postselected circuits. In order to treat postselection in CVs, we consider finitely resolved homodyne detectors, corresponding to a realistic scheme based on discrete probability distributions of the measurement outcomes. The unavoidable errors stemming from the use of finitely squeezed states are suppressed through a qubit-into-oscillator Gottesman-Kitaev-Preskill encoding of quantum information, which was previously shown to enable fault-tolerant CV quantum computation. Finally, we show that, in order to render postselected computational classes in CVs meaningful, a logarithmic scaling of the squeezing parameter with the circuit size is necessary, translating into a polynomial scaling of the input energy.

Short-term stability of sleep and heart rate variability in good sleepers and patients with insomnia: for some measures, one night is enough.

PubMed

Israel, Benjamin; Buysse, Daniel J; Krafty, Robert T; Begley, Amy; Miewald, Jean; Hall, Martica

2012-09-01

Quantify the short-term stability of multiple indices of sleep and nocturnal physiology in good sleeper controls and primary insomnia patients. Intra-class correlation coefficients (ICC) were used to quantify the short-term stability of study outcomes. Sleep laboratory. Fifty-four adults with primary insomnia (PI) and 22 good sleeper controls (GSC). Visually scored sleep outcomes included indices of sleep duration, continuity, and architecture. Quantitative EEG outcomes included power in the delta, theta, alpha, sigma, and beta bands during NREM sleep. Power spectral analysis was used to estimate high-frequency heart rate variability (HRV) and the ratio of low- to high-frequency HRV power during NREM and REM sleep. With the exception of percent stage 3+4 sleep; visually scored sleep outcomes did not exhibit short-term stability across study nights. Most QEEG outcomes demonstrated short-term stability in both groups. Although power in the beta band was stable in the PI group (ICC = 0.75), it tended to be less stable in GSCs (ICC = 0.55). Both measures of cardiac autonomic tone exhibited short-term stability in GSCs and PIs during NREM and REM sleep. Most QEEG bandwidths and HRV during sleep show high short-term stability in good sleepers and patients with insomnia alike. One night of data is, thus, sufficient to derive reliable estimates of these outcomes in studies focused on group differences or correlates of QEEG and/or HRV. In contrast, one night of data is unlikely to generate reliable estimates of PSG-assessed sleep duration, continuity or architecture, with the exception of slow wave sleep.

Patterns of Exclusionary Discipline by School Typology, Ethnicity, and Their Interaction

ERIC Educational Resources Information Center

Noltemeyer, Amity; Mcloughlin, Caven S.

2010-01-01

Although exclusionary discipline has been linked to a variety of negative student outcomes, it continues to be utilized by schools. This study investigates two critical variables as they relate to exclusionary discipline: School typology (i.e., urban, rural, suburban) and student ethnicity. Using data from 326 Ohio school districts, a MANCOVA…

The Early Risers Preventive Intervention: Testing for Six-year Outcomes and Mediational Processes

ERIC Educational Resources Information Center

Bernat, Debra H.; August, Gerald J.; Hektner, Joel M.; Bloomquist, Michael L.

2007-01-01

We examined effects of the Early Risers "Skills for Success" early-age-targeted prevention program on serious conduct problems following 5 years of continuous intervention and one year of follow-up. We also examined if intervention effects on proximally-targeted variables found after 3 years mediated intervention effects on conduct…

Circumstances, Resources, and Weight Status Outcomes among Middle School Students

ERIC Educational Resources Information Center

Fitzpatrick, Kevin M.; Willis, Don; O'Connor, Gail

2014-01-01

Obesity continues to plague U.S. school-age populations. A number of individual/structural circumstances have been identified as increasing the risk of poor health among children. The article's aim is to examine some of these circumstances and their relationship to students being overweight/obese, while highlighting resource variables as potential…

Early language processing efficiency predicts later receptive vocabulary outcomes in children born preterm.

PubMed

Marchman, Virginia A; Adams, Katherine A; Loi, Elizabeth C; Fernald, Anne; Feldman, Heidi M

2016-01-01

As rates of prematurity continue to rise, identifying which preterm children are at increased risk for learning disabilities is a public health imperative. Identifying continuities between early and later skills in this vulnerable population can also illuminate fundamental neuropsychological processes that support learning in all children. At 18 months adjusted age, we used socioeconomic status (SES), medical variables, parent-reported vocabulary, scores on the Bayley Scales of Infant and Toddler Development (third edition) language composite, and children's lexical processing speed in the looking-while-listening (LWL) task as predictor variables in a sample of 30 preterm children. Receptive vocabulary as measured by the Peabody Picture Vocabulary Test (fourth edition) at 36 months was the outcome. Receptive vocabulary was correlated with SES, but uncorrelated with degree of prematurity or a composite of medical risk. Importantly, lexical processing speed was the strongest predictor of receptive vocabulary (r = -.81), accounting for 30% unique variance. Individual differences in lexical processing efficiency may be able to serve as a marker for information processing skills that are critical for language learning.

Interventions with children and parents to improve physical activity and body mass index: a meta-analysis.

PubMed

Dellert, Jane Cerruti; Johnson, Portia

2014-01-01

Examine the effect of interventions with parents and children on children's physical activity and body mass index (BMI). Computerized searches for intervention studies published between 1990 and 2011 used multiple ProQuest databases, including unpublished dissertations and theses to minimize publication bias. English-language, intervention-testing studies of children, parents, or families with outcomes of physical activity or BMI were retrieved from peer-reviewed journals, dissertations, and theses. Eliminated studies had no control or comparison group; had no continuous outcome variable; had no physical activity/exercise and/or BMI as outcomes; or had incomplete statistics necessary for meta-analysis (means, standard deviations, or confidence intervals). Twenty-one studies met inclusion criteria. Quality criteria were control group, objective outcome variable measure, clarity of variable definitions, and number and reason for subject withdrawal. Meta-analysis on the raw difference of means estimated mean weighted effect size (MWES) assessed dispersion of effects and computed a summary effect. MWES for interventions with parents and children on physical activity (Z = 2.92; confidence interval [CI] = .09 to .48; p = .002) and on BMI for interventions with children alone (Z = -2.10; CI = -.16 to -.01; p = .02) was significant. A significant effect on physical activity but not on BMI was found when interventions included both parents and their children.

Measuring and communicating meaningful outcomes in neonatology: A family perspective.

PubMed

Janvier, Annie; Farlow, Barbara; Baardsnes, Jason; Pearce, Rebecca; Barrington, Keith J

2016-12-01

Medium- and long-term outcomes have been collected and described among survivors of neonatal intensive care units for decades, for a number of purposes: (1) quality control within units, (2) comparisons of outcomes between NICUs, (3) clinical trials (whether an intervention improves outcomes), (4) end-of-life decision-making, (5) to better understand the effects of neonatal conditions and/or interventions on organs and/or long-term health, and finally (6) to better prepare parents for the future. However, the outcomes evaluated have been selected by investigators, based on feasibility, availability, cost, stability, and on what investigators consider to be important. Many of the routinely measured outcomes have major limitations: they may not correlate well with long-term difficulties, they may artificially divide continuous outcomes into dichotomous ones, and may have no clear relationship with quality of life and functioning of children and their families. Several investigations, such as routine term cerebral resonance imaging for preterm infants, have also not yet been shown to improve the outcome of children nor their families. In this article, the most common variables used in neonatology as well as some variables which are rarely measured but may be of equal importance for families are presented. The manner in which these outcomes are communicated to families will be examined, as well as recommendations to optimize communication with parents. Copyright © 2016 Elsevier Inc. All rights reserved.

Influences of personality traits and continuation intentions on physical activity participation within the theory of planned behaviour.

PubMed

Chatzisarantis, Nikos L D; Hagger, Martin S

2008-01-01

Previous research has suggested that the theory of planned behaviour is insufficient in capturing all the antecedents of physical activity participation and that continuation intentions or personality traits may improve the predictive validity of the model. The present study examined the combined effects of continuation intentions and personality traits on health behaviour within the theory of planned behaviour. To examine these effects, 180 university students (N = 180, Male = 87, Female = 93, Age = 19.14 years, SD = 0.94) completed self-report measures of the theory of planned behaviour, personality traits and continuation intentions. After 5 weeks, perceived achievement of behavioural outcomes and actual participation in physical activities were assessed. Results supported discriminant validity between continuation intentions, conscientiousness and extroversion and indicated that perceived achievement of behavioural outcomes and continuation intentions of failure predicted physical activity participation after controlling for personality effects, past behaviour and other variables in the theory of planned behaviour. In addition, results indicated that conscientiousness moderated the effects of continuation intentions of failure on physical activity such that continuation intentions of failure predicted physical activity participation among conscientious and not among less conscientious individuals. These findings suggest that the effects of continuation intentions on health behaviour are contingent on personality characteristics.

Pediatric Ventilator-Associated Infections: The Ventilator-Associated INfection Study.

PubMed

Willson, Douglas F; Hoot, Michelle; Khemani, Robinder; Carrol, Christopher; Kirby, Aileen; Schwarz, Adam; Gedeit, Rainer; Nett, Sholeen T; Erickson, Simon; Flori, Heidi; Hays, Spencer; Hall, Mark

2017-01-01

Suspected ventilator-associated infection is the most common reason for antibiotics in the PICU. We sought to characterize the clinical variables associated with continuing antibiotics after initial evaluation for suspected ventilator-associated infection and to determine whether clinical variables or antibiotic treatment influenced outcomes. Prospective, observational cohort study conducted in 47 PICUs in the United States, Canada, and Australia. Two hundred twenty-nine pediatric patients ventilated more than 48 hours undergoing respiratory secretion cultures were enrolled as "suspected ventilator-associated infection" in a prospective cohort study, those receiving antibiotics of less than or equal to 3 days were categorized as "evaluation only," and greater than 3 days as "treated." Demographics, diagnoses, comorbidities, culture results, and clinical data were compared between evaluation only and treated subjects and between subjects with positive versus negative cultures. PICUs in 47 hospitals in the United States, Canada, and Australia. All patients undergoing respiratory secretion cultures during the 6 study periods. None. Treated subjects differed from evaluation-only subjects only in frequency of positive cultures (79% vs 36%; p < 0.0001). Subjects with positive cultures were more likely to have chronic lung disease, tracheostomy, and shorter PICU stay, but there were no differences in ventilator days or mortality. Outcomes were similar in subjects with positive or negative cultures irrespective of antibiotic treatment. Immunocompromise and higher Pediatric Logistic Organ Dysfunction scores were the only variables associated with mortality in the overall population, but treated subjects with endotracheal tubes had significantly lower mortality. Positive respiratory cultures were the primary determinant of continued antibiotic treatment in children with suspected ventilator-associated infection. Positive cultures were not associated with worse outcomes irrespective of antibiotic treatment although the lower mortality in treated subjects with endotracheal tubes is notable. The necessity of continuing antibiotics for a positive respiratory culture in suspected ventilator-associated infection requires further study.

Use of generalised additive models to categorise continuous variables in clinical prediction

PubMed Central

2013-01-01

Background In medical practice many, essentially continuous, clinical parameters tend to be categorised by physicians for ease of decision-making. Indeed, categorisation is a common practice both in medical research and in the development of clinical prediction rules, particularly where the ensuing models are to be applied in daily clinical practice to support clinicians in the decision-making process. Since the number of categories into which a continuous predictor must be categorised depends partly on the relationship between the predictor and the outcome, the need for more than two categories must be borne in mind. Methods We propose a categorisation methodology for clinical-prediction models, using Generalised Additive Models (GAMs) with P-spline smoothers to determine the relationship between the continuous predictor and the outcome. The proposed method consists of creating at least one average-risk category along with high- and low-risk categories based on the GAM smooth function. We applied this methodology to a prospective cohort of patients with exacerbated chronic obstructive pulmonary disease. The predictors selected were respiratory rate and partial pressure of carbon dioxide in the blood (PCO2), and the response variable was poor evolution. An additive logistic regression model was used to show the relationship between the covariates and the dichotomous response variable. The proposed categorisation was compared to the continuous predictor as the best option, using the AIC and AUC evaluation parameters. The sample was divided into a derivation (60%) and validation (40%) samples. The first was used to obtain the cut points while the second was used to validate the proposed methodology. Results The three-category proposal for the respiratory rate was ≤ 20;(20,24];> 24, for which the following values were obtained: AIC=314.5 and AUC=0.638. The respective values for the continuous predictor were AIC=317.1 and AUC=0.634, with no statistically significant differences being found between the two AUCs (p =0.079). The four-category proposal for PCO2 was ≤ 43;(43,52];(52,65];> 65, for which the following values were obtained: AIC=258.1 and AUC=0.81. No statistically significant differences were found between the AUC of the four-category option and that of the continuous predictor, which yielded an AIC of 250.3 and an AUC of 0.825 (p =0.115). Conclusions Our proposed method provides clinicians with the number and location of cut points for categorising variables, and performs as successfully as the original continuous predictor when it comes to developing clinical prediction rules. PMID:23802742

Autonomic Impairment in Severe Traumatic Brain Injury: A Multimodal Neuromonitoring Study.

PubMed

Sykora, Marek; Czosnyka, Marek; Liu, Xiuyun; Donnelly, Joseph; Nasr, Nathalie; Diedler, Jennifer; Okoroafor, Francois; Hutchinson, Peter; Menon, David; Smielewski, Peter

2016-06-01

Autonomic impairment after acute traumatic brain injury has been associated independently with both increased morbidity and mortality. Links between autonomic impairment and increased intracranial pressure or impaired cerebral autoregulation have been described as well. However, relationships between autonomic impairment, intracranial pressure, impaired cerebral autoregulation, and outcome remain poorly explored. Using continuous measurements of heart rate variability and baroreflex sensitivity we aimed to test whether autonomic markers are associated with functional outcome and mortality independently of intracranial variables. Further, we aimed to evaluate the relationships between autonomic functions, intracranial pressure, and cerebral autoregulation. Retrospective analysis of a prospective database. Neurocritical care unit in a university hospital. Sedated patients with severe traumatic brain injury. Waveforms of intracranial pressure and arterial blood pressure, baseline Glasgow Coma Scale and 6 months Glasgow Outcome Scale were recorded. Baroreflex sensitivity was assessed every 10 seconds using a modified cross-correlational method. Frequency domain analyses of heart rate variability were performed automatically every 10 seconds from a moving 300 seconds of the monitoring time window. Mean values of baroreflex sensitivity, heart rate variability, intracranial pressure, arterial blood pressure, cerebral perfusion pressure, and impaired cerebral autoregulation over the entire monitoring period were calculated for each patient. Two hundred and sixty-two patients with a median age of 36 years entered the analysis. The median admission Glasgow Coma Scale was 6, the median Glasgow Outcome Scale was 3, and the mortality at 6 months was 23%. Baroreflex sensitivity (adjusted odds ratio, 0.9; p = 0.02) and relative power of a high frequency band of heart rate variability (adjusted odds ratio, 1.05; p < 0.001) were individually associated with mortality, independently of age, admission Glasgow Coma Scale, intracranial pressure, pressure reactivity index, or cerebral perfusion pressure. Baroreflex sensitivity showed no correlation with intracranial pressure or cerebral perfusion pressure; the correlation with pressure reactivity index was strong in older patients (age, > 60 yr). The relative power of high frequency correlated significantly with intracranial pressure and cerebral perfusion pressure, but not with pressure reactivity index. The relative power of low frequency correlated significantly with pressure reactivity index. Autonomic impairment, as measured by heart rate variability and baroreflex sensitivity, is significantly associated with increased mortality after traumatic brain injury. These effects, though partially interlinked, seem to be independent of age, trauma severity, intracranial pressure, or autoregulatory status, and thus represent a discrete phenomenon in the pathophysiology of traumatic brain injury. Continuous measurements of heart rate variability and baroreflex sensitivity in the neuromonitoring setting of severe traumatic brain injury may carry novel pathophysiological and predictive information.

Three-part joint modeling methods for complex functional data mixed with zero-and-one-inflated proportions and zero-inflated continuous outcomes with skewness.

PubMed

Li, Haocheng; Staudenmayer, John; Wang, Tianying; Keadle, Sarah Kozey; Carroll, Raymond J

2018-02-20

We take a functional data approach to longitudinal studies with complex bivariate outcomes. This work is motivated by data from a physical activity study that measured 2 responses over time in 5-minute intervals. One response is the proportion of time active in each interval, a continuous proportions with excess zeros and ones. The other response, energy expenditure rate in the interval, is a continuous variable with excess zeros and skewness. This outcome is complex because there are 3 possible activity patterns in each interval (inactive, partially active, and completely active), and those patterns, which are observed, induce both nonrandom and random associations between the responses. More specifically, the inactive pattern requires a zero value in both the proportion for active behavior and the energy expenditure rate; a partially active pattern means that the proportion of activity is strictly between zero and one and that the energy expenditure rate is greater than zero and likely to be moderate, and the completely active pattern means that the proportion of activity is exactly one, and the energy expenditure rate is greater than zero and likely to be higher. To address these challenges, we propose a 3-part functional data joint modeling approach. The first part is a continuation-ratio model to reorder the ordinal valued 3 activity patterns. The second part models the proportions when they are in interval (0,1). The last component specifies the skewed continuous energy expenditure rate with Box-Cox transformations when they are greater than zero. In this 3-part model, the regression structures are specified as smooth curves measured at various time points with random effects that have a correlation structure. The smoothed random curves for each variable are summarized using a few important principal components, and the association of the 3 longitudinal components is modeled through the association of the principal component scores. The difficulties in handling the ordinal and proportional variables are addressed using a quasi-likelihood type approximation. We develop an efficient algorithm to fit the model that also involves the selection of the number of principal components. The method is applied to physical activity data and is evaluated empirically by a simulation study. Copyright © 2017 John Wiley & Sons, Ltd.

Epidemiologic research using probabilistic outcome definitions.

PubMed

Cai, Bing; Hennessy, Sean; Lo Re, Vincent; Small, Dylan S

2015-01-01

Epidemiologic studies using electronic healthcare data often define the presence or absence of binary clinical outcomes by using algorithms with imperfect specificity, sensitivity, and positive predictive value. This results in misclassification and bias in study results. We describe and evaluate a new method called probabilistic outcome definition (POD) that uses logistic regression to estimate the probability of a clinical outcome using multiple potential algorithms and then uses multiple imputation to make valid inferences about the risk ratio or other epidemiologic parameters of interest. We conducted a simulation to evaluate the performance of the POD method with two variables that can predict the true outcome and compared the POD method with the conventional method. The simulation results showed that when the true risk ratio is equal to 1.0 (null), the conventional method based on a binary outcome provides unbiased estimates. However, when the risk ratio is not equal to 1.0, the traditional method, either using one predictive variable or both predictive variables to define the outcome, is biased when the positive predictive value is <100%, and the bias is very severe when the sensitivity or positive predictive value is poor (less than 0.75 in our simulation). In contrast, the POD method provides unbiased estimates of the risk ratio both when this measure of effect is equal to 1.0 and not equal to 1.0. Even when the sensitivity and positive predictive value are low, the POD method continues to provide unbiased estimates of the risk ratio. The POD method provides an improved way to define outcomes in database research. This method has a major advantage over the conventional method in that it provided unbiased estimates of risk ratios and it is easy to use. Copyright © 2014 John Wiley & Sons, Ltd.

Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

PubMed

Yagui, Ana Cristina Zanon; Vale, Luciana Assis Pires Andrade; Haddad, Luciana Branco; Prado, Cristiane; Rossi, Felipe Souza; Deutsch, Alice D Agostini; Rebello, Celso Moura

2011-01-01

To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p < 0.05. There were no differences between the groups with regard to demographic data, CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

Alcohol and drug treatment outcome studies: new methodological review (2005-2010) and comparison with past reviews.

PubMed

Robinson, Sean M; Sobell, Linda Carter; Sobell, Mark B; Arcidiacono, Steven; Tzall, David

2014-01-01

Several methodological reviews of alcohol treatment outcome studies and one review of drug studies have been published over the past 40 years. Although past reviews demonstrated methodological improvements in alcohol studies, they also found continued deficiencies. The current review allows for an updated evaluation of the methodological rigor of alcohol and drug studies and, by utilizing inclusion criteria similar to previous reviews, it allows for a comparative review over time. In addition, this is the first review that compares the methodology of alcohol and drug treatment outcome studies published during the same time period. The methodology for 25 alcohol and 11 drug treatment outcome studies published from 2005 through 2010 that met the review's inclusion criteria was evaluated. The majority of variables evaluated were used in prior reviews. The current review found that more alcohol and drug treatment outcome studies are now using continuous substance use measures and assessing problem severity. Although there have been methodological improvements over time, the current reviews differed little from their most recent past counterpart. Despite this finding, some areas, particularly the continued low reporting of demographic data, needs strengthening. Improvement in the methodological rigor of alcohol and drug treatment outcome studies has occurred over time. The current review found few differences between alcohol and drug study methodologies as well as few differences between the current review and the most recent past alcohol and drug reviews. © 2013 Elsevier Ltd. All rights reserved.

Examining the Error of Mis-Specifying Nonlinear Confounding Effect With Application on Accelerometer-Measured Physical Activity.

PubMed

Lee, Paul H

2017-06-01

Some confounders are nonlinearly associated with dependent variables, but they are often adjusted using a linear term. The purpose of this study was to examine the error of mis-specifying the nonlinear confounding effect. We carried out a simulation study to investigate the effect of adjusting for a nonlinear confounder in the estimation of a causal relationship between the exposure and outcome in 3 ways: using a linear term, binning into 5 equal-size categories, or using a restricted cubic spline of the confounder. Continuous, binary, and survival outcomes were simulated. We examined the confounder across varying measurement error. In addition, we performed a real data analysis examining the 3 strategies to handle the nonlinear effects of accelerometer-measured physical activity in the National Health and Nutrition Examination Survey 2003-2006 data. The mis-specification of a nonlinear confounder had little impact on causal effect estimation for continuous outcomes. For binary and survival outcomes, this mis-specification introduced bias, which could be eliminated using spline adjustment only when there is small measurement error of the confounder. Real data analysis showed that the associations between high blood pressure, high cholesterol, and diabetes and mortality adjusted for physical activity with restricted cubic spline were about 3% to 11% larger than their counterparts adjusted with a linear term. For continuous outcomes, confounders with nonlinear effects can be adjusting with a linear term. Spline adjustment should be used for binary and survival outcomes on confounders with small measurement error.

Secondary outcome analysis for data from an outcome-dependent sampling design.

PubMed

Pan, Yinghao; Cai, Jianwen; Longnecker, Matthew P; Zhou, Haibo

2018-04-22

Outcome-dependent sampling (ODS) scheme is a cost-effective way to conduct a study. For a study with continuous primary outcome, an ODS scheme can be implemented where the expensive exposure is only measured on a simple random sample and supplemental samples selected from 2 tails of the primary outcome variable. With the tremendous cost invested in collecting the primary exposure information, investigators often would like to use the available data to study the relationship between a secondary outcome and the obtained exposure variable. This is referred as secondary analysis. Secondary analysis in ODS designs can be tricky, as the ODS sample is not a random sample from the general population. In this article, we use the inverse probability weighted and augmented inverse probability weighted estimating equations to analyze the secondary outcome for data obtained from the ODS design. We do not make any parametric assumptions on the primary and secondary outcome and only specify the form of the regression mean models, thus allow an arbitrary error distribution. Our approach is robust to second- and higher-order moment misspecification. It also leads to more precise estimates of the parameters by effectively using all the available participants. Through simulation studies, we show that the proposed estimator is consistent and asymptotically normal. Data from the Collaborative Perinatal Project are analyzed to illustrate our method. Copyright © 2018 John Wiley & Sons, Ltd.

Assessing factors related to waist circumference and obesity: application of a latent variable model.

PubMed

Dalvand, Sahar; Koohpayehzadeh, Jalil; Karimlou, Masoud; Asgari, Fereshteh; Rafei, Ali; Seifi, Behjat; Niksima, Seyed Hassan; Bakhshi, Enayatollah

2015-01-01

Because the use of BMI (Body Mass Index) alone as a measure of adiposity has been criticized, in the present study our aim was to fit a latent variable model to simultaneously examine the factors that affect waist circumference (continuous outcome) and obesity (binary outcome) among Iranian adults. Data included 18,990 Iranian individuals aged 20-65 years that are derived from the third National Survey of Noncommunicable Diseases Risk Factors in Iran. Using latent variable model, we estimated the relation of two correlated responses (waist circumference and obesity) with independent variables including age, gender, PR (Place of Residence), PA (physical activity), smoking status, SBP (Systolic Blood Pressure), DBP (Diastolic Blood Pressure), CHOL (cholesterol), FBG (Fasting Blood Glucose), diabetes, and FHD (family history of diabetes). All variables were related to both obesity and waist circumference (WC). Older age, female sex, being an urban resident, physical inactivity, nonsmoking, hypertension, hypercholesterolemia, hyperglycemia, diabetes, and having family history of diabetes were significant risk factors that increased WC and obesity. Findings from this study of Iranian adult settings offer more insights into factors associated with high WC and high prevalence of obesity in this population.

[Clinical research IV. Relevancy of the statistical test chosen].

PubMed

Talavera, Juan O; Rivas-Ruiz, Rodolfo

2011-01-01

When we look at the difference between two therapies or the association of a risk factor or prognostic indicator with its outcome, we need to evaluate the accuracy of the result. This assessment is based on a judgment that uses information about the study design and statistical management of the information. This paper specifically mentions the relevance of the statistical test selected. Statistical tests are chosen mainly from two characteristics: the objective of the study and type of variables. The objective can be divided into three test groups: a) those in which you want to show differences between groups or inside a group before and after a maneuver, b) those that seek to show the relationship (correlation) between variables, and c) those that aim to predict an outcome. The types of variables are divided in two: quantitative (continuous and discontinuous) and qualitative (ordinal and dichotomous). For example, if we seek to demonstrate differences in age (quantitative variable) among patients with systemic lupus erythematosus (SLE) with and without neurological disease (two groups), the appropriate test is the "Student t test for independent samples." But if the comparison is about the frequency of females (binomial variable), then the appropriate statistical test is the χ(2).

Sensitivity subgroup analysis based on single-center vs. multi-center trial status when interpreting meta-analyses pooled estimates: the logical way forward.

PubMed

Alexander, Paul E; Bonner, Ashley J; Agarwal, Arnav; Li, Shelly-Anne; Hariharan, Abishek; Izhar, Zain; Bhatnagar, Neera; Alba, Carolina; Akl, Elie A; Fei, Yutong; Guyatt, Gordon H; Beyene, Joseph

2016-06-01

Prior studies regarding whether single-center trial estimates are larger than multi-center are equivocal. We examined the extent to which single-center trials yield systematically larger effects than multi-center trials. We searched the 119 core clinical journals and the Cochrane Database of Systematic Reviews for meta-analyses (MAs) of randomized controlled trials (RCTs) published during 2012. In this meta-epidemiologic study, for binary variables, we computed the pooled ratio of ORs (RORs), and for continuous outcomes mean difference in standardized mean differences (SMDs), we conducted weighted random-effects meta-regression and random-effects MA modeling. Our primary analyses were restricted to MAs that included at least five RCTs and in which at least 25% of the studies used each of single trial center (SC) and more trial center (MC) designs. We identified 81 MAs for the odds ratio (OR) and 43 for the SMD outcome measures. Based on our analytic plan, our primary analysis (core) is based on 25 MAs/241 RCTs (binary outcome) and 18 MAs/173 RCTs (continuous outcome). Based on the core analysis, we found no difference in magnitude of effect between SC and MC for binary outcomes [RORs: 1.02; 95% confidence interval (CI): 0.83, 1.24; I(2) 20.2%]. Effect sizes were systematically larger for SC than MC for the continuous outcome measure (mean difference in SMDs: -0.13; 95% CI: -0.21, -0.05; I(2) 0%). Our results do not support prior findings of larger effects in SC than MC trials addressing binary outcomes but show a very similar small increase in effect in SC than MC trials addressing continuous outcomes. Authors of systematic reviews would be wise to include all trials irrespective of SC vs. MC design and address SC vs. MC status as a possible explanation of heterogeneity (and consider sensitivity analyses). Copyright © 2015 Elsevier Inc. All rights reserved.

Goal specificity: a proxy measure for improvements in environmental outcomes in collaborative governance.

PubMed

Biddle, Jennifer C; Koontz, Tomas M

2014-12-01

Collaborative governance critics continually call for evidence to support its prevalent use. As is often the case in environmental policy, environmental outcomes occur at a rate incompatible with political agendas. In addition, a multitude of possibly confounding variables makes it difficult to correlate collaborative governance processes with environmental outcomes. The findings of this study offer empirical evidence that collaborative processes have a measurable, beneficial effect on environmental outcomes. Through the use of a unique paired-waterbody design, our dataset reduced the potential for confounding variables to impact our environmental outcome measurements. The results of a path analysis indicate that the output of setting specific pollutant reduction goals is significantly related to watershed partnerships' level of attainment of their environmental improvement goals. The action of setting specific goals (e.g. percentage of load reductions in pollutant levels) is fostered by sustained participation from partnership members throughout the lifecycle of the collaborative. In addition, this study demonstrates the utility of logic modeling for environmental planning and management, and suggests that the process of setting specific pollutant reduction goals is a useful proxy measure for reporting progress towards improvements in environmental outcomes when long-term environmental data are not available. Copyright © 2014 Elsevier Ltd. All rights reserved.

The long-term significance of teacher-rated hyperactivity and reading ability in childhood: findings from two longitudinal studies.

PubMed

McGee, Rob; Prior, Margot; Willams, Sheila; Smart, Diana; Sanson, Anne

2002-11-01

The aims of this study were twofold: first, to examine behavioural and academic outcomes of children with hyperactivity, using data from two longitudinal studies; and second, to examine comparable psychosocial outcomes for children with early reading difficulties. Measures of teacher-rated persistent hyperactivity, and reading ability obtained during early primary school were available for children from the Australian Temperament Project and the Dunedin Multidisciplinary Health and Development Study. Both samples were followed up to assess behavioural and academic outcomes during the adolescent and early adult years. Family background, antisocial behaviour and literacy were controlled in the first set of analyses to examine the influence of early hyperactivity. There were strong linear relationships between early hyperactivity and later adverse outcomes. Adjustment for other childhood variables suggested that early hyperactivity was associated with continuing school difficulties, problems with attention and poor reading in adolescence. Early reading difficulties, after controlling for early hyperactivity, predicted continuing reading problems in high school and leaving school with no qualifications. The findings suggest that there are dual pathways from early inattentive behaviours to later inattention and reading problems, and from early reading difficulties to substantial impairments in later academic outcomes.

Leveraging prognostic baseline variables to gain precision in randomized trials

PubMed Central

Colantuoni, Elizabeth; Rosenblum, Michael

2015-01-01

We focus on estimating the average treatment effect in a randomized trial. If baseline variables are correlated with the outcome, then appropriately adjusting for these variables can improve precision. An example is the analysis of covariance (ANCOVA) estimator, which applies when the outcome is continuous, the quantity of interest is the difference in mean outcomes comparing treatment versus control, and a linear model with only main effects is used. ANCOVA is guaranteed to be at least as precise as the standard unadjusted estimator, asymptotically, under no parametric model assumptions and also is locally semiparametric efficient. Recently, several estimators have been developed that extend these desirable properties to more general settings that allow any real-valued outcome (e.g., binary or count), contrasts other than the difference in mean outcomes (such as the relative risk), and estimators based on a large class of generalized linear models (including logistic regression). To the best of our knowledge, we give the first simulation study in the context of randomized trials that compares these estimators. Furthermore, our simulations are not based on parametric models; instead, our simulations are based on resampling data from completed randomized trials in stroke and HIV in order to assess estimator performance in realistic scenarios. We provide practical guidance on when these estimators are likely to provide substantial precision gains and describe a quick assessment method that allows clinical investigators to determine whether these estimators could be useful in their specific trial contexts. PMID:25872751

Predictive factors in patients with hepatocellular carcinoma receiving sorafenib therapy using time-dependent receiver operating characteristic analysis.

PubMed

Nishikawa, Hiroki; Nishijima, Norihiro; Enomoto, Hirayuki; Sakamoto, Azusa; Nasu, Akihiro; Komekado, Hideyuki; Nishimura, Takashi; Kita, Ryuichi; Kimura, Toru; Iijima, Hiroko; Nishiguchi, Shuhei; Osaki, Yukio

2017-01-01

To investigate variables before sorafenib therapy on the clinical outcomes in hepatocellular carcinoma (HCC) patients receiving sorafenib and to further assess and compare the predictive performance of continuous parameters using time-dependent receiver operating characteristics (ROC) analysis. A total of 225 HCC patients were analyzed. We retrospectively examined factors related to overall survival (OS) and progression free survival (PFS) using univariate and multivariate analyses. Subsequently, we performed time-dependent ROC analysis of continuous parameters which were significant in the multivariate analysis in terms of OS and PFS. Total sum of area under the ROC in all time points (defined as TAAT score) in each case was calculated. Our cohort included 175 male and 50 female patients (median age, 72 years) and included 158 Child-Pugh A and 67 Child-Pugh B patients. The median OS time was 0.68 years, while the median PFS time was 0.24 years. On multivariate analysis, gender, body mass index (BMI), Child-Pugh classification, extrahepatic metastases, tumor burden, aspartate aminotransferase (AST) and alpha-fetoprotein (AFP) were identified as significant predictors of OS and ECOG-performance status, Child-Pugh classification and extrahepatic metastases were identified as significant predictors of PFS. Among three continuous variables (i.e., BMI, AST and AFP), AFP had the highest TAAT score for the entire cohort. In subgroup analyses, AFP had the highest TAAT score except for Child-Pugh B and female among three continuous variables. In continuous variables, AFP could have higher predictive accuracy for survival in HCC patients undergoing sorafenib therapy.

The use of aortic balloon occlusion in traumatic shock: first report from the ABO trauma registry.

PubMed

Sadeghi, M; Nilsson, K F; Larzon, T; Pirouzram, A; Toivola, A; Skoog, P; Idoguchi, K; Kon, Y; Ishida, T; Matsumara, Y; Matsumoto, J; Reva, V; Maszkowski, M; Bersztel, A; Caragounis, E; Falkenberg, M; Handolin, L; Kessel, B; Hebron, D; Coccolini, F; Ansaloni, L; Madurska, M J; Morrison, J J; Hörer, T M

2017-08-11

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique for temporary stabilization of patients with non-compressible torso hemorrhage. This technique has been increasingly used worldwide during the past decade. Despite the good outcomes of translational studies, clinical studies are divided. The aim of this multicenter-international study was to capture REBOA-specific data and outcomes. REBOA practicing centers were invited to join this online register, which was established in September 2014. REBOA cases were reported, both retrospective and prospective. Demographics, injury patterns, hemodynamic variables, REBOA-specific data, complications and 30-days mortality were reported. Ninety-six cases from 6 different countries were reported between 2011 and 2016. Mean age was 52 ± 22 years and 88% of the cases were blunt trauma with a median injury severity score (ISS) of 41 (IQR 29-50). In the majority of the cases, Zone I REBOA was used. Median systolic blood pressure before balloon inflation was 60 mmHg (IQR 40-80), which increased to 100 mmHg (IQR 80-128) after inflation. Continuous occlusion was applied in 52% of the patients, and 48% received non-continuous occlusion. Occlusion time longer than 60 min was reported as 38 and 14% in the non-continuous and continuous groups, respectively. Complications, such as extremity compartment syndrome (n = 3), were only noted in the continuous occlusion group. The 30-day mortality for non-continuous REBOA was 48%, and 64% for continuous occlusion. This observational multicenter study presents results regarding continuous and non-continuous REBOA with favorable outcomes. However, further prospective studies are needed to be able to draw conclusions on morbidity and mortality.

Pressure Ulcers in the United States' Inpatient Population From 2008 to 2012: Results of a Retrospective Nationwide Study.

PubMed

Bauer, Karen; Rock, Kathryn; Nazzal, Munier; Jones, Olivia; Qu, Weikai

2016-11-01

Pressure ulcers are common, increase patient morbidity and mortality, and costly for patients, their families, and the health care system. A retrospective study was conducted to evaluate the impact of pressure ulcers on short-term outcomes in United States inpatient populations and to identify patient characteristics associated with having 1 or more pressure ulcers. The US Nationwide Inpatient Sample (NIS) database was analyzed using the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9 CM) diagnosis codes as the screening tool for all inpatient pressure ulcers recorded from 2008 to 2012. Patient demographics and comorbid conditions, as identified by ICD-9 code, were extracted, along with primary outcomes of length of stay (LOS), total hospital charge (TC), inhospital mortality, and discharge disposition. Continuous variables with normal distribution were expressed in terms of mean and standard deviation. Group comparisons were performed using t-test or ANOVA test. Continuous nonnormal distributed variables such as LOS and TC were expressed in terms of median, and nonparametric tests were used to compare the differences between groups. Categorical data were presented in terms of percentages of the number of cases within each group. Chi-squared tests were used to compare categorical data in different groups. For multivariate analysis, linear regressions (for continuous variable) and logistic regression (for categorical variables) were used to analyze the possible risk factors for the investigated outcomes of LOS, TC, inhospital mortality, and patient disposition. Coefficients were calculated with multivariate regression with all included patients versus patients with pressure ulcers alone. The 5-year average number of admitted patients with at least 1 pressure ulcer was determined to be 670 767 (average overall rate: 1.8%). Statistically significant differences between patients with and without pressure ulcers were observed for median LOS (7 days [mean 11.1 ± 15] compared to 3 days [mean 4.6 ± 6.8]) and median TC ($36 500 [mean $72 000 ± $122 900] compared to $17 200 [mean $32 200 ± $57 500]). The mortality rate in patients with a pressure ulcer was significantly higher than in patients without a pressure ulcer (9.1% versus 1.8%, OR = 5.08, CI: 5.03-5.1, P <0.001). Pressure ulcers were significantly more common in patients who were older or had malnutrition. The results of this study confirm the importance of prevention initiatives to help reduce the negative impact of pressure ulcers on patient outcomes and costs of care.

The intermediate endpoint effect in logistic and probit regression

PubMed Central

MacKinnon, DP; Lockwood, CM; Brown, CH; Wang, W; Hoffman, JM

2010-01-01

Background An intermediate endpoint is hypothesized to be in the middle of the causal sequence relating an independent variable to a dependent variable. The intermediate variable is also called a surrogate or mediating variable and the corresponding effect is called the mediated, surrogate endpoint, or intermediate endpoint effect. Clinical studies are often designed to change an intermediate or surrogate endpoint and through this intermediate change influence the ultimate endpoint. In many intermediate endpoint clinical studies the dependent variable is binary, and logistic or probit regression is used. Purpose The purpose of this study is to describe a limitation of a widely used approach to assessing intermediate endpoint effects and to propose an alternative method, based on products of coefficients, that yields more accurate results. Methods The intermediate endpoint model for a binary outcome is described for a true binary outcome and for a dichotomization of a latent continuous outcome. Plots of true values and a simulation study are used to evaluate the different methods. Results Distorted estimates of the intermediate endpoint effect and incorrect conclusions can result from the application of widely used methods to assess the intermediate endpoint effect. The same problem occurs for the proportion of an effect explained by an intermediate endpoint, which has been suggested as a useful measure for identifying intermediate endpoints. A solution to this problem is given based on the relationship between latent variable modeling and logistic or probit regression. Limitations More complicated intermediate variable models are not addressed in the study, although the methods described in the article can be extended to these more complicated models. Conclusions Researchers are encouraged to use an intermediate endpoint method based on the product of regression coefficients. A common method based on difference in coefficient methods can lead to distorted conclusions regarding the intermediate effect. PMID:17942466

Finding structure in data using multivariate tree boosting

PubMed Central

Miller, Patrick J.; Lubke, Gitta H.; McArtor, Daniel B.; Bergeman, C. S.

2016-01-01

Technology and collaboration enable dramatic increases in the size of psychological and psychiatric data collections, but finding structure in these large data sets with many collected variables is challenging. Decision tree ensembles such as random forests (Strobl, Malley, & Tutz, 2009) are a useful tool for finding structure, but are difficult to interpret with multiple outcome variables which are often of interest in psychology. To find and interpret structure in data sets with multiple outcomes and many predictors (possibly exceeding the sample size), we introduce a multivariate extension to a decision tree ensemble method called gradient boosted regression trees (Friedman, 2001). Our extension, multivariate tree boosting, is a method for nonparametric regression that is useful for identifying important predictors, detecting predictors with nonlinear effects and interactions without specification of such effects, and for identifying predictors that cause two or more outcome variables to covary. We provide the R package ‘mvtboost’ to estimate, tune, and interpret the resulting model, which extends the implementation of univariate boosting in the R package ‘gbm’ (Ridgeway et al., 2015) to continuous, multivariate outcomes. To illustrate the approach, we analyze predictors of psychological well-being (Ryff & Keyes, 1995). Simulations verify that our approach identifies predictors with nonlinear effects and achieves high prediction accuracy, exceeding or matching the performance of (penalized) multivariate multiple regression and multivariate decision trees over a wide range of conditions. PMID:27918183

Mediation analysis when a continuous mediator is measured with error and the outcome follows a generalized linear model

PubMed Central

Valeri, Linda; Lin, Xihong; VanderWeele, Tyler J.

2014-01-01

Mediation analysis is a popular approach to examine the extent to which the effect of an exposure on an outcome is through an intermediate variable (mediator) and the extent to which the effect is direct. When the mediator is mis-measured the validity of mediation analysis can be severely undermined. In this paper we first study the bias of classical, non-differential measurement error on a continuous mediator in the estimation of direct and indirect causal effects in generalized linear models when the outcome is either continuous or discrete and exposure-mediator interaction may be present. Our theoretical results as well as a numerical study demonstrate that in the presence of non-linearities the bias of naive estimators for direct and indirect effects that ignore measurement error can take unintuitive directions. We then develop methods to correct for measurement error. Three correction approaches using method of moments, regression calibration and SIMEX are compared. We apply the proposed method to the Massachusetts General Hospital lung cancer study to evaluate the effect of genetic variants mediated through smoking on lung cancer risk. PMID:25220625

Influence of physician factors on the effectiveness of a continuing medical education intervention.

PubMed

Flores, Sergio; Reyes, Hortensia; Perez-Cuevas, Ricardo

2006-01-01

Continuing medical education (CME) is essential for improving the quality of care in primary health care settings. This study's objective was to determine how the characteristics of family physicians influenced the effectiveness of a multifaceted CME intervention to improve the management of acute respiratory infection (ARI) or type 2 diabetes (DM2). A secondary analysis was conducted based on data from 121 family physicians, who participated in the educational intervention study. The outcome variable was positive change in physician's performance for treatment of ARI or DM2. The exposure variable was multifaceted CME intervention. Independent variables were professional physicians and organizational characteristics. Analysis included log binomial regression modeling. Factors influencing positive change included, for ARI, participation in the CME intervention and medical director interested in that condition and for DM2, participation in the CME intervention, medical director interested in DM2, and being a teacher. Physicians' characteristics and organizational environment influence the effectiveness of educational intervention and are therefore relevant to the implementation of CME strategies.

A prospective, randomized, controlled study comparing Gynemesh, a synthetic mesh, and Pelvicol, a biologic graft, in the surgical treatment of recurrent cystocele.

PubMed

Natale, F; La Penna, C; Padoa, A; Agostini, M; De Simone, E; Cervigni, M

2009-01-01

We compared safety and efficacy of Gynemesh PS and Pelvicol for recurrent cystocele repair. One hundred ninety patients were randomly divided into Gynemesh PS and Pelvicol groups and underwent tension-free cystocele repair. The Chi-square test was used to compare categorical variables, the paired t test for continuous parametric variables, and the Mann-Whitney test for continuous nonparametric variables. Ninety-six Gynemesh PS patients and 94 Pelvicol patients were studied. Mesh erosions occurred in 6.3% of Gynemesh PS patients. No erosions were observed in Pelvicol patients (p = 0.02). Objective cure was 71.9% for Gynemesh PS and 56.4% for Pelvicol (p = 0.06). Subjective cure was the same in both groups except for better sexuality in the Pelvicol group. At 24 months follow-up, only Gynemesh PS patients had mesh erosions. Anatomical outcome was similar in the two groups. Pelvicol gave a better impact on voiding and sexuality.

Proposing a New Conceptual Model and an Exemplar Measure Using Health Information: Technology to Examine the Impact of Relational Nurse Continuity on Hospital-Acquired Pressure Ulcers

PubMed Central

STIFTER, Janet; YAO, Yingwei; LOPEZ, Karen Dunn; KHOKHAR, Ashfaq; WILKIE, Diana J.; KEENAN, Gail M.

2015-01-01

The influence of the staffing variable nurse continuity on patient outcomes has been rarely studied and with inconclusive results. Multiple definitions and an absence of systematic methods for measuring the influence of continuity have resulted in its exclusion from nurse-staffing studies and conceptual models. We present a new conceptual model and an innovative use of health information technology to measure nurse continuity and to demonstrate the potential for bringing the results of big data science back to the bedside. Understanding the power of big data to address critical clinical issues may foster a new direction for nursing administration theory development. PMID:26244480

Outcome of Endodontically Treated Teeth Diagnosed With Cracked Tooth

DTIC Science & Technology

2015-06-01

However, variable symptoms complicate the diagnosis (9). In a study of 32 patients presenting with diffuse longstanding orofacial pain eventually...883-92. 22)Byrnjulsen A, Fristad I, Grevstad T, Hals-Kvinnsland I. Incompletely fractured teeth associated with diffuse longstanding orofacial pain ...cracked tooth is highly associated with discomfort. Patients often describe a momentary, sudden, sharp, lancinating pain that results in continuous tooth

Action Control, Motivated Strategies, and Integrative Motivation as Predictors of Language Learning Affect and the Intention to Continue Learning French

ERIC Educational Resources Information Center

MacIntyre, Peter D.; Blackie, Rebecca A.

2012-01-01

The present study examines the relative ability of variables from three motivational frameworks to predict four non-linguistic outcomes of language learning. The study examines Action Control Theory with its measures of (1) hesitation, (2) volatility and (3) rumination. The study also examined Pintrich's expectancy-value model that uses measures…

Kaizen method for esophagectomy patients: improved quality control, outcomes, and decreased costs.

PubMed

Iannettoni, Mark D; Lynch, William R; Parekh, Kalpaj R; McLaughlin, Kelley A

2011-04-01

The majority of costs associated with esophagectomy are related to the initial 3 days of hospital stay requiring intensive care unit stays, ventilator support, and intraoperative time. Additional costs arise from hospital-based services. The major cost increases are related to complications associated with the procedure. We attempted to define these costs and identify expense management by streamlining care through strict adherence to patient care maps, operative standardization, and rapid discharge planning to reduce variability. Utilizing methods of Kaizen philosophy we evaluated all processes related to the entire experience of esophageal resection. This process has taken over 5 years to achieve, with quality and cost being tracked over this time period. Cost analysis included expenses related to intensive care unit, anesthesia, disposables, and hospital services. Quality improvement measures were related to intraoperative complications, in-hospital complications, and postoperative outcomes. The Institutional Review Board approved the use of anonymous data from standard clinical practice because no additional treatment was planned (observational study). Utilizing a continuous process improvement methodology, a 43% reduction in cost per case has been achieved with a significant increase in contribution margin for esophagectomy. The length of stay has been reduced from 14 days to 5. With intraoperative and postoperative standardization the leak rate has dropped from 12% to less than 3% to no leaks in our current Kaizen modification of care in our last 64 patients. Utilizing lean manufacturing techniques and continuous process evaluation we have attempted to eliminate variability, standardized the phases of care resulting in improved outcomes, decreased length of stay, and improved contribution margins. These Kaizen improvements require continuous interventions, strict adherence to care maps, and input from all levels for quality improvements. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

A stratification approach using logit-based models for confounder adjustment in the study of continuous outcomes.

PubMed

Tan, Chuen Seng; Støer, Nathalie C; Chen, Ying; Andersson, Marielle; Ning, Yilin; Wee, Hwee-Lin; Khoo, Eric Yin Hao; Tai, E-Shyong; Kao, Shih Ling; Reilly, Marie

2017-01-01

The control of confounding is an area of extensive epidemiological research, especially in the field of causal inference for observational studies. Matched cohort and case-control study designs are commonly implemented to control for confounding effects without specifying the functional form of the relationship between the outcome and confounders. This paper extends the commonly used regression models in matched designs for binary and survival outcomes (i.e. conditional logistic and stratified Cox proportional hazards) to studies of continuous outcomes through a novel interpretation and application of logit-based regression models from the econometrics and marketing research literature. We compare the performance of the maximum likelihood estimators using simulated data and propose a heuristic argument for obtaining the residuals for model diagnostics. We illustrate our proposed approach with two real data applications. Our simulation studies demonstrate that our stratification approach is robust to model misspecification and that the distribution of the estimated residuals provides a useful diagnostic when the strata are of moderate size. In our applications to real data, we demonstrate that parity and menopausal status are associated with percent mammographic density, and that the mean level and variability of inpatient blood glucose readings vary between medical and surgical wards within a national tertiary hospital. Our work highlights how the same class of regression models, available in most statistical software, can be used to adjust for confounding in the study of binary, time-to-event and continuous outcomes.

Echocardiographic predictors of adverse outcomes after continuous left ventricular assist device implantation.

PubMed

Topilsky, Yan; Oh, Jae K; Shah, Dipesh K; Boilson, Barry A; Schirger, John A; Kushwaha, Sudhir S; Pereira, Naveen L; Park, Soon J

2011-03-01

The purpose of the study was to identify echocardiographic predictors of adverse outcome in patients implanted with continuous-flow left ventricular assist devices (LVAD). Continuous flow LVAD have become part of the standard of care for the treatment of advanced heart failure. However, knowledge of echocardiographic predictors of outcome after LVAD are lacking. Overall, 83 patients received continuous-flow LVAD (HeartMate II, Thoratec Corporation, Pleasanton, California) from February 2007 to June 2010. The LVAD database, containing various echocardiographic parameters, was examined to analyze their influence on in-hospital mortality, a compound cardiac event (in-hospital mortality or acute right ventricular [RV] dysfunction), and long-term mortality. Eight patients died before discharge (operative mortality 9.6%), and another 15 patients were considered to have acute RV dysfunction immediately after surgery. Patients with relatively small left ventricular end-diastolic diameters (<63 mm) had significantly higher risk for in-hospital mortality (odds ratio [OR]: 0.9; 95% confidence interval [CI]: 0.83 to 0.99; p = 0.04) or occurrence of the compound cardiac event (OR: 0.89; 95% CI: 0.84 to 0.95; p < 0.001). The most significant predictor of outcome was the decreased timing interval between the onset and the cessation of tricuspid regurgitation flow corrected for heart rate (TRDc), a surrogate for early systolic equalization of RV and right atrial pressure. Short TRDc predicted in-hospital mortality (OR: 0.85; 95% CI: 0.74 to 0.97; p = 0.01) and the compound cardiac event (OR: 0.83; 95% CI: 0.74 to 0.91; p < 0.0001). Multivariate analysis based on a logistic regression model demonstrated that the accuracy of predicting the 30-day compound adverse outcome was improved with the addition of echocardiographic variables when added to the commonly used hemodynamic or clinical scores. TRDc predicted long-term survival, with adjusted risk ratios of 0.89 for death from any cause (95% CI: 0.83 to 0.96; p = 0.003) and 0.88 for cardiac-related death (95% CI: 0.77 to 0.98; p = 0.03). The presence of either a relatively small left ventricle (<63 mm) or early systolic equalization of RV and right atrial pressure (short TRDc) demonstrated by echocardiography is associated with increased 30-day morbidity and mortality. Prediction of early adverse outcomes by echocardiographic parameters is additive to laboratory or hemodynamic variables. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Vascular Glucose Sensor Symposium: Continuous Glucose Monitoring Systems (CGMS) for Hospitalized and Ambulatory Patients at Risk for Hyperglycemia, Hypoglycemia, and Glycemic Variability.

PubMed

Joseph, Jeffrey I; Torjman, Marc C; Strasma, Paul J

2015-07-01

Hyperglycemia, hypoglycemia, and glycemic variability have been associated with increased morbidity, mortality, length of stay, and cost in a variety of critical care and non-critical care patient populations in the hospital. The results from prospective randomized clinical trials designed to determine the risks and benefits of intensive insulin therapy and tight glycemic control have been confusing; and at times conflicting. The limitations of point-of-care blood glucose (BG) monitoring in the hospital highlight the great clinical need for an automated real-time continuous glucose monitoring system (CGMS) that can accurately measure the concentration of glucose every few minutes. Automation and standardization of the glucose measurement process have the potential to significantly improve BG control, clinical outcome, safety and cost. © 2015 Diabetes Technology Society.

Medical review licensing outcomes in drivers with visual field loss in Victoria, Australia

PubMed Central

Muir, Carlyn; Charlton, Judith L; Odell, Morris; Keeffe, Jill; Wood, Joanne; Bohensky, Megan; Fildes, Brian; Oxley, Jennifer; Bentley, Sharon; Rizzo, Matthew

2017-01-01

Background Good vision is essential for safe driving and studies have associated visual impairment with an increased crash risk. Currently, there is little information about the medical review of drivers with visual field loss. This study examines the prevalence of visual field loss among drivers referred for medical review in one Australian jurisdiction and investigates factors associated with licence outcome in this group. Methods A random sample of 10,000 (31.25 per cent) medical review cases was extracted for analysis from the Victorian licensing authority. Files were screened for the presence of six visual field-related medical conditions. Data were captured on a range of variables, including referral source, age, gender, health status, crash history and licence outcome. Prevalence analyses were univariate and descriptive. Logistic regression was used to assess factors associated with licence outcomes in the visual field loss group. Results Approximately 1.9 per cent of the 10,000 medical review cases screened had a visual field loss condition identified (n=194). Among the visual field loss group, 57.2 per cent were permitted to continue driving (conditional/unconditional licence). Primary referral sources were the police, self-referrals and general medical practitioners. Key factors associated with licence test outcomes were visual field condition, age group, crash involvement and referral to the Driver Licensing Authority’s Medical Advisors. Those who were younger had a crash involvement triggering referral and those who were referred to the Medical Advisors were more likely to have a positive licensing outcome. Conclusion The evidence base for making licensing decisions is complicated by the variable causes, patterns, progressions and measuring technologies for visual field loss. This study highlighted that the involvement of an expert medical advisory service in Victoria resulted in an increased likelihood that drivers with visual field loss will be allowed to continue driving. Further research is warranted to explore issues relating to severity of field loss and the capacity for compensation. PMID:27530283

Continuity of care in mental health: understanding and measuring a complex phenomenon.

PubMed

Burns, T; Catty, J; White, S; Clement, S; Ellis, G; Jones, I R; Lissouba, P; McLaren, S; Rose, D; Wykes, T

2009-02-01

Continuity of care is considered by patients and clinicians an essential feature of good quality care in long-term disorders, yet there is general agreement that it is a complex concept. Most policies emphasize it and encourage systems to promote it. Despite this, there is no accepted definition or measure against which to test policies or interventions designed to improve continuity. We aimed to operationalize a multi-axial model of continuity of care and to use factor analysis to determine its validity for severe mental illness. A multi-axial model of continuity of care comprising eight facets was operationalized for quantitative data collection from mental health service users using 32 variables. Of these variables, 22 were subsequently entered into a factor analysis as independent components, using data from a clinical population considered to require long-term consistent care. Factor analysis produced seven independent continuity factors accounting for 62.5% of the total variance. These factors, Experience and Relationship, Regularity, Meeting Needs, Consolidation, Managed Transitions, Care Coordination and Supported Living, were close but not identical to the original theoretical model. We confirmed that continuity of care is multi-factorial. Our seven factors are intuitively meaningful and appear to work in mental health. These factors should be used as a starting-point in research into the determinants and outcomes of continuity of care in long-term disorders.

A new model of wheezing severity in young children using the validated ISAAC wheezing module: A latent variable approach with validation in independent cohorts.

PubMed

Brunwasser, Steven M; Gebretsadik, Tebeb; Gold, Diane R; Turi, Kedir N; Stone, Cosby A; Datta, Soma; Gern, James E; Hartert, Tina V

2018-01-01

The International Study of Asthma and Allergies in Children (ISAAC) Wheezing Module is commonly used to characterize pediatric asthma in epidemiological studies, including nearly all airway cohorts participating in the Environmental Influences on Child Health Outcomes (ECHO) consortium. However, there is no consensus model for operationalizing wheezing severity with this instrument in explanatory research studies. Severity is typically measured using coarsely-defined categorical variables, reducing power and potentially underestimating etiological associations. More precise measurement approaches could improve testing of etiological theories of wheezing illness. We evaluated a continuous latent variable model of pediatric wheezing severity based on four ISAAC Wheezing Module items. Analyses included subgroups of children from three independent cohorts whose parents reported past wheezing: infants ages 0-2 in the INSPIRE birth cohort study (Cohort 1; n = 657), 6-7-year-old North American children from Phase One of the ISAAC study (Cohort 2; n = 2,765), and 5-6-year-old children in the EHAAS birth cohort study (Cohort 3; n = 102). Models were estimated using structural equation modeling. In all cohorts, covariance patterns implied by the latent variable model were consistent with the observed data, as indicated by non-significant χ2 goodness of fit tests (no evidence of model misspecification). Cohort 1 analyses showed that the latent factor structure was stable across time points and child sexes. In both cohorts 1 and 3, the latent wheezing severity variable was prospectively associated with wheeze-related clinical outcomes, including physician asthma diagnosis, acute corticosteroid use, and wheeze-related outpatient medical visits when adjusting for confounders. We developed an easily applicable continuous latent variable model of pediatric wheezing severity based on items from the well-validated ISAAC Wheezing Module. This model prospectively associates with asthma morbidity, as demonstrated in two ECHO birth cohort studies, and provides a more statistically powerful method of testing etiologic hypotheses of childhood wheezing illness and asthma.

Interpreting the concordance statistic of a logistic regression model: relation to the variance and odds ratio of a continuous explanatory variable.

PubMed

Austin, Peter C; Steyerberg, Ewout W

2012-06-20

When outcomes are binary, the c-statistic (equivalent to the area under the Receiver Operating Characteristic curve) is a standard measure of the predictive accuracy of a logistic regression model. An analytical expression was derived under the assumption that a continuous explanatory variable follows a normal distribution in those with and without the condition. We then conducted an extensive set of Monte Carlo simulations to examine whether the expressions derived under the assumption of binormality allowed for accurate prediction of the empirical c-statistic when the explanatory variable followed a normal distribution in the combined sample of those with and without the condition. We also examine the accuracy of the predicted c-statistic when the explanatory variable followed a gamma, log-normal or uniform distribution in combined sample of those with and without the condition. Under the assumption of binormality with equality of variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the product of the standard deviation of the normal components (reflecting more heterogeneity) and the log-odds ratio (reflecting larger effects). Under the assumption of binormality with unequal variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the standardized difference of the explanatory variable in those with and without the condition. In our Monte Carlo simulations, we found that these expressions allowed for reasonably accurate prediction of the empirical c-statistic when the distribution of the explanatory variable was normal, gamma, log-normal, and uniform in the entire sample of those with and without the condition. The discriminative ability of a continuous explanatory variable cannot be judged by its odds ratio alone, but always needs to be considered in relation to the heterogeneity of the population.

Reporting and Methodology of Multivariable Analyses in Prognostic Observational Studies Published in 4 Anesthesiology Journals: A Methodological Descriptive Review.

PubMed

Guglielminotti, Jean; Dechartres, Agnès; Mentré, France; Montravers, Philippe; Longrois, Dan; Laouénan, Cedric

2015-10-01

Prognostic research studies in anesthesiology aim to identify risk factors for an outcome (explanatory studies) or calculate the risk of this outcome on the basis of patients' risk factors (predictive studies). Multivariable models express the relationship between predictors and an outcome and are used in both explanatory and predictive studies. Model development demands a strict methodology and a clear reporting to assess its reliability. In this methodological descriptive review, we critically assessed the reporting and methodology of multivariable analysis used in observational prognostic studies published in anesthesiology journals. A systematic search was conducted on Medline through Web of Knowledge, PubMed, and journal websites to identify observational prognostic studies with multivariable analysis published in Anesthesiology, Anesthesia & Analgesia, British Journal of Anaesthesia, and Anaesthesia in 2010 and 2011. Data were extracted by 2 independent readers. First, studies were analyzed with respect to reporting of outcomes, design, size, methods of analysis, model performance (discrimination and calibration), model validation, clinical usefulness, and STROBE (i.e., Strengthening the Reporting of Observational Studies in Epidemiology) checklist. A reporting rate was calculated on the basis of 21 items of the aforementioned points. Second, they were analyzed with respect to some predefined methodological points. Eighty-six studies were included: 87.2% were explanatory and 80.2% investigated a postoperative event. The reporting was fairly good, with a median reporting rate of 79% (75% in explanatory studies and 100% in predictive studies). Six items had a reporting rate <36% (i.e., the 25th percentile), with some of them not identified in the STROBE checklist: blinded evaluation of the outcome (11.9%), reason for sample size (15.1%), handling of missing data (36.0%), assessment of colinearity (17.4%), assessment of interactions (13.9%), and calibration (34.9%). When reported, a few methodological shortcomings were observed, both in explanatory and predictive studies, such as an insufficient number of events of the outcome (44.6%), exclusion of cases with missing data (93.6%), or categorization of continuous variables (65.1%.). The reporting of multivariable analysis was fairly good and could be further improved by checking reporting guidelines and EQUATOR Network website. Limiting the number of candidate variables, including cases with missing data, and not arbitrarily categorizing continuous variables should be encouraged.

Semiparametric methods for estimation of a nonlinear exposure-outcome relationship using instrumental variables with application to Mendelian randomization.

PubMed

Staley, James R; Burgess, Stephen

2017-05-01

Mendelian randomization, the use of genetic variants as instrumental variables (IV), can test for and estimate the causal effect of an exposure on an outcome. Most IV methods assume that the function relating the exposure to the expected value of the outcome (the exposure-outcome relationship) is linear. However, in practice, this assumption may not hold. Indeed, often the primary question of interest is to assess the shape of this relationship. We present two novel IV methods for investigating the shape of the exposure-outcome relationship: a fractional polynomial method and a piecewise linear method. We divide the population into strata using the exposure distribution, and estimate a causal effect, referred to as a localized average causal effect (LACE), in each stratum of population. The fractional polynomial method performs metaregression on these LACE estimates. The piecewise linear method estimates a continuous piecewise linear function, the gradient of which is the LACE estimate in each stratum. Both methods were demonstrated in a simulation study to estimate the true exposure-outcome relationship well, particularly when the relationship was a fractional polynomial (for the fractional polynomial method) or was piecewise linear (for the piecewise linear method). The methods were used to investigate the shape of relationship of body mass index with systolic blood pressure and diastolic blood pressure. © 2017 The Authors Genetic Epidemiology Published by Wiley Periodicals, Inc.

Semiparametric methods for estimation of a nonlinear exposure‐outcome relationship using instrumental variables with application to Mendelian randomization

PubMed Central

Staley, James R.

2017-01-01

ABSTRACT Mendelian randomization, the use of genetic variants as instrumental variables (IV), can test for and estimate the causal effect of an exposure on an outcome. Most IV methods assume that the function relating the exposure to the expected value of the outcome (the exposure‐outcome relationship) is linear. However, in practice, this assumption may not hold. Indeed, often the primary question of interest is to assess the shape of this relationship. We present two novel IV methods for investigating the shape of the exposure‐outcome relationship: a fractional polynomial method and a piecewise linear method. We divide the population into strata using the exposure distribution, and estimate a causal effect, referred to as a localized average causal effect (LACE), in each stratum of population. The fractional polynomial method performs metaregression on these LACE estimates. The piecewise linear method estimates a continuous piecewise linear function, the gradient of which is the LACE estimate in each stratum. Both methods were demonstrated in a simulation study to estimate the true exposure‐outcome relationship well, particularly when the relationship was a fractional polynomial (for the fractional polynomial method) or was piecewise linear (for the piecewise linear method). The methods were used to investigate the shape of relationship of body mass index with systolic blood pressure and diastolic blood pressure. PMID:28317167

The impact of visit-to-visit systolic blood pressure variability on residual renal function and left ventricular hypertrophy in peritoneal dialysis patients

PubMed

Tian, Jun-Ping; Wang, Hong; Tian, Xin-Kui; Du, Feng-He; Wang, Tao

2018-04-30

Background/aim: Blood pressure (BP) variability is more closely associated with adverse outcomes than ‘usual’ BP in the general population. Residual renal function (RRF) and left ventricular hypertrophy (LVH) are thought to be predictors of poor outcome in dialysis patients. However, only a few studies have focused on BP variation and its link to RRF, LVH, and outcome in peritoneal dialysis (PD) patients. Therefore, we aimed to explore the effect of visit-to-visit BP variability on RRF and LVH in continuous ambulatory PD (CAPD) patients. Materials and methods: We performed an observational study that included all prevalent PD patients between 1 February 2006 and 31 January 2007. All patients underwent BP measurements, pulse wave velocity (PWV), cardiac ultrasound, and biochemical examination during the 1-year observation. Patients were divided into the HBPV group (higher BP variability) and LBPV group (lower BP variability) based on the standard deviation of systolic BP (SBP). Results: There were 70 patients recruited for the final analysis. Patients with HBPV had a higher SBP as compared to patients with LBPV at baseline. Renal Kt/V decreased significantly from 0.50 ± 0.49 to 0.32 ± 0.35 (P < 0.01) in HBPV group (but not in the LBPV group) during follow-up. Patients with HBPV also showed a higher left ventricular mass index (LVMI) and PWV than those with LBPV at the end of follow-up. Conclusion: Our study suggests that BP variability may affect RRF in PD patients. PD patients with HBPV had a faster decline in RRF and higher PWV and LVH.

Estimation of Causal Mediation Effects for a Dichotomous Outcome in Multiple-Mediator Models using the Mediation Formula

PubMed Central

Nelson, Suchitra; Albert, Jeffrey M.

2013-01-01

Mediators are intermediate variables in the causal pathway between an exposure and an outcome. Mediation analysis investigates the extent to which exposure effects occur through these variables, thus revealing causal mechanisms. In this paper, we consider the estimation of the mediation effect when the outcome is binary and multiple mediators of different types exist. We give a precise definition of the total mediation effect as well as decomposed mediation effects through individual or sets of mediators using the potential outcomes framework. We formulate a model of joint distribution (probit-normal) using continuous latent variables for any binary mediators to account for correlations among multiple mediators. A mediation formula approach is proposed to estimate the total mediation effect and decomposed mediation effects based on this parametric model. Estimation of mediation effects through individual or subsets of mediators requires an assumption involving the joint distribution of multiple counterfactuals. We conduct a simulation study that demonstrates low bias of mediation effect estimators for two-mediator models with various combinations of mediator types. The results also show that the power to detect a non-zero total mediation effect increases as the correlation coefficient between two mediators increases, while power for individual mediation effects reaches a maximum when the mediators are uncorrelated. We illustrate our approach by applying it to a retrospective cohort study of dental caries in adolescents with low and high socioeconomic status. Sensitivity analysis is performed to assess the robustness of conclusions regarding mediation effects when the assumption of no unmeasured mediator-outcome confounders is violated. PMID:23650048

Estimation of causal mediation effects for a dichotomous outcome in multiple-mediator models using the mediation formula.

PubMed

Wang, Wei; Nelson, Suchitra; Albert, Jeffrey M

2013-10-30

Mediators are intermediate variables in the causal pathway between an exposure and an outcome. Mediation analysis investigates the extent to which exposure effects occur through these variables, thus revealing causal mechanisms. In this paper, we consider the estimation of the mediation effect when the outcome is binary and multiple mediators of different types exist. We give a precise definition of the total mediation effect as well as decomposed mediation effects through individual or sets of mediators using the potential outcomes framework. We formulate a model of joint distribution (probit-normal) using continuous latent variables for any binary mediators to account for correlations among multiple mediators. A mediation formula approach is proposed to estimate the total mediation effect and decomposed mediation effects based on this parametric model. Estimation of mediation effects through individual or subsets of mediators requires an assumption involving the joint distribution of multiple counterfactuals. We conduct a simulation study that demonstrates low bias of mediation effect estimators for two-mediator models with various combinations of mediator types. The results also show that the power to detect a nonzero total mediation effect increases as the correlation coefficient between two mediators increases, whereas power for individual mediation effects reaches a maximum when the mediators are uncorrelated. We illustrate our approach by applying it to a retrospective cohort study of dental caries in adolescents with low and high socioeconomic status. Sensitivity analysis is performed to assess the robustness of conclusions regarding mediation effects when the assumption of no unmeasured mediator-outcome confounders is violated. Copyright © 2013 John Wiley & Sons, Ltd.

Using Concentration Curves to Assess Organization-Specific Relationships between Surgeon Volumes and Outcomes.

PubMed

Kanter, Michael H; Huang, Yii-Chieh; Kally, Zina; Gordon, Margo A; Meltzer, Charles

2018-06-01

A well-documented association exists between higher surgeon volumes and better outcomes for many procedures, but surgeons may be reluctant to change practice patterns without objective, credible, and near real-time data on their performance. In addition, published thresholds for procedure volumes may be biased or perceived as arbitrary; typical reports compare surgeons grouped into discrete procedure volume categories, even though the volume-outcomes relationship is likely continuous. The concentration curves methodology, which has been used to analyze whether health outcomes vary with socioeconomic status, was adapted to explore the association between procedure volume and outcomes as a continuous relationship so that data for all surgeons within a health care organization could be included. Using widely available software and requiring minimal analytic expertise, this approach plots cumulative percentages of two variables of interest against each other and assesses the characteristics of the resulting curve. Organization-specific relationships between surgeon volumes and outcomes were examined for three example types of procedures: uncomplicated hysterectomies, infant circumcisions, and total thyroidectomies. The concentration index was used to assess whether outcomes were equally distributed unrelated to volumes. For all three procedures, the concentration curve methodology identified associations between surgeon procedure volumes and selected outcomes that were specific to the organization. The concentration indices confirmed the higher prevalence of examined outcomes among low-volume surgeons. The curves supported organizational discussions about surgical quality. Concentration curves require minimal resources to identify organization- and procedure-specific relationships between surgeon procedure volumes and outcomes and can support quality improvement. Copyright © 2018 The Joint Commission. Published by Elsevier Inc. All rights reserved.

Regression Discontinuity for Causal Effect Estimation in Epidemiology.

PubMed

Oldenburg, Catherine E; Moscoe, Ellen; Bärnighausen, Till

Regression discontinuity analyses can generate estimates of the causal effects of an exposure when a continuously measured variable is used to assign the exposure to individuals based on a threshold rule. Individuals just above the threshold are expected to be similar in their distribution of measured and unmeasured baseline covariates to individuals just below the threshold, resulting in exchangeability. At the threshold exchangeability is guaranteed if there is random variation in the continuous assignment variable, e.g., due to random measurement error. Under exchangeability, causal effects can be identified at the threshold. The regression discontinuity intention-to-treat (RD-ITT) effect on an outcome can be estimated as the difference in the outcome between individuals just above (or below) versus just below (or above) the threshold. This effect is analogous to the ITT effect in a randomized controlled trial. Instrumental variable methods can be used to estimate the effect of exposure itself utilizing the threshold as the instrument. We review the recent epidemiologic literature reporting regression discontinuity studies and find that while regression discontinuity designs are beginning to be utilized in a variety of applications in epidemiology, they are still relatively rare, and analytic and reporting practices vary. Regression discontinuity has the potential to greatly contribute to the evidence base in epidemiology, in particular on the real-life and long-term effects and side-effects of medical treatments that are provided based on threshold rules - such as treatments for low birth weight, hypertension or diabetes.

Poverty, Pregnancy, and Birth Outcomes: A Study of the Earned Income Tax Credit.

PubMed

Hamad, Rita; Rehkopf, David H

2015-09-01

Economic interventions are increasingly recognised as a mechanism to address perinatal health outcomes among disadvantaged groups. In the US, the earned income tax credit (EITC) is the largest poverty alleviation programme. Little is known about its effects on perinatal health among recipients and their children. We exploit quasi-random variation in the size of EITC payments to examine the effects of income on perinatal health. The study sample includes women surveyed in the 1979 National Longitudinal Survey of Youth (n = 2985) and their children born during 1986-2000 (n = 4683). Outcome variables include utilisation of prenatal and postnatal care, use of alcohol and tobacco during pregnancy, term birth, birthweight, and breast-feeding status. We first examine the health effects of both household income and EITC payment size using multivariable linear regressions. We then employ instrumental variables analysis to estimate the causal effect of income on perinatal health, using EITC payment size as an instrument for household income. We find that EITC payment size is associated with better levels of several indicators of perinatal health. Instrumental variables analysis, however, does not reveal a causal association between household income and these health measures. Our findings suggest that associations between income and perinatal health may be confounded by unobserved characteristics, but that EITC income improves perinatal health. Future studies should continue to explore the impacts of economic interventions on perinatal health outcomes, and investigate how different forms of income transfers may have different impacts. © 2015 John Wiley & Sons Ltd.

Echocardiographic variables after left ventricular assist device implantation associated with adverse outcome.

PubMed

Topilsky, Yan; Hasin, Tal; Oh, Jae K; Borgeson, Daniel D; Boilson, Barry A; Schirger, John A; Clavell, Alfredo L; Frantz, Robert P; Tsutsui, Rayji; Liu, Mingya; Maltais, Simon; Kushwaha, Sudhir S; Pereira, Naveen L; Park, Soon J

2011-11-01

Operative mortality after left ventricular assist device (LVAD) implantation is heavily influenced by patient selection and the technical difficulty of surgery. However, how we treat our patients and LVAD setting may affect the patient outcome beyond this period. We postulated that the presence of echocardiographic variables 1 month after surgery suggesting appropriate degree of LV unloading and an adequate forward flow would be important in determining clinical outcomes after the initial successful LVAD implantation. We retrospectively analyzed various variables in echocardiographic examinations performed 30 days after LVAD implant in 76 consecutive patients receiving continuous flow device for their association with a compound end point (90-day mortality, readmission for heart failure, or New York Heart Association class III or higher at the end of the 90-day period). The echocardiographic associations examined included estimated LVAD flow, with and without native LV contribution, interventricular septal position, the status of aortic valve opening, an estimated left atrial pressure (ELAP), the mitral flow E-wave deceleration time, and the ratio of deceleration time to E-wave velocity (mitral deceleration index [MDI]). Four patients died during the 30- to 90-day period, 6 patients were readmitted for heart failure, and 25 patients were considered to have New York Heart Association class III or higher at the end of the 90-day period. Variables associated with adverse outcome included increased ELAP (odds ratio, 1.30 [1.16-1.48]; P<0.0001), MDI <2 ms/[cm/s] (odds ratio, 4.4 implantation [1.22-18]; P=0.02) and decreased tricuspid lateral annulus velocity (odds ratio, 0.70 implantation [0.48-0.95]; P=0.02). A leftward deviation of interventricular septum was associated with a worse outcome (odds ratio, 3.03 implantation [1.21-13.3]; P=0.01). Mortality and heart failure after LVAD surgery appear to be predominantly determined by echocardiographic evidence of inefficient unloading of the left ventricle and persistence of right ventricular dysfunction. Increased estimated LA pressure and short MDI are associated with worse mid term outcome. Leftward deviation of the septum is associated with worse outcome as well.

Impact of body mass index on outcome in stroke patients treated with intravenous thrombolysis.

PubMed

Gensicke, H; Wicht, A; Bill, O; Zini, A; Costa, P; Kägi, G; Stark, R; Seiffge, D J; Traenka, C; Peters, N; Bonati, L H; Giovannini, G; De Marchis, G M; Poli, L; Polymeris, A; Vanacker, P; Sarikaya, H; Lyrer, P A; Pezzini, A; Vandelli, L; Michel, P; Engelter, S T

2016-12-01

The impact of body mass index (BMI) on outcome in stroke patients treated with intravenous thrombolysis (IVT) was investigated. In a multicentre IVT-register-based observational study, BMI with (i) poor 3-month outcome (i.e. modified Rankin Scale scores 3-6), (ii) death and (iii) symptomatic intracranial haemorrhage (sICH) based on criteria of the ECASS II trial was compared. BMI was used as a continuous and categorical variable distinguishing normal weight (reference group 18.5-24.9 kg/m 2 ) from underweight (<18.5 kg/m 2 ), overweight (25-29.9 kg/m 2 ) and obese (≥30 kg/m 2 ) patients. Univariable and multivariable regression analyses with adjustments for age and stroke severity were done and odds ratios with 95% confidence intervals [OR (95% CI)] were calculated. Of 1798 patients, 730 (40.6%) were normal weight, 55 (3.1%) were underweight, 717 (39.9%) overweight and 295 (16.4%) obese. Poor outcome occurred in 38.1% of normal weight patients and did not differ significantly from underweight (45.5%), overweight (36.1%) and obese (32.5%) patients. The same was true for death (9.5% vs. 14.5%, 9.6% and 7.5%) and sICH (3.9% vs. 5.5%, 4.3%, 2.7%). Neither in univariable nor in multivariable analyses did the risks of poor outcome, death or sICH differ significantly between BMI groups. BMI as a continuous variable was not associated with poor outcome, death or sICH in unadjusted [OR (95% CI) 0.99 (0.97-1.01), 0.98 (0.95-1.02), 0.98 (0.94-1.04)] or adjusted analyses [OR (95% CI) 1.01 (0.98-1.03), 0.99 (0.95-1.05), 1.01 (0.97-1.05)], respectively. In this largest study to date, investigating the impact of BMI in IVT-treated stroke patients, BMI had no prognostic meaning with regard to 3-month functional outcome, death or occurrence of sICH. © 2016 EAN.

Antibiotic Dosing in Continuous Renal Replacement Therapy.

PubMed

Shaw, Alexander R; Mueller, Bruce A

2017-07-01

Appropriate antibiotic dosing is critical to improve outcomes in critically ill patients with sepsis. The addition of continuous renal replacement therapy makes achieving appropriate antibiotic dosing more difficult. The lack of continuous renal replacement therapy standardization results in treatment variability between patients and may influence whether appropriate antibiotic exposure is achieved. The aim of this study was to determine if continuous renal replacement therapy effluent flow rate impacts attaining appropriate antibiotic concentrations when conventional continuous renal replacement therapy antibiotic doses were used. This study used Monte Carlo simulations to evaluate the effect of effluent flow rate variance on pharmacodynamic target attainment for cefepime, ceftazidime, levofloxacin, meropenem, piperacillin, and tazobactam. Published demographic and pharmacokinetic parameters for each antibiotic were used to develop a pharmacokinetic model. Monte Carlo simulations of 5000 patients were evaluated for each antibiotic dosing regimen at the extremes of Kidney Disease: Improving Global Outcomes guidelines recommended effluent flow rates (20 and 35 mL/kg/h). The probability of target attainment was calculated using antibiotic-specific pharmacodynamic targets assessed over the first 72 hours of therapy. Most conventional published antibiotic dosing recommendations, except for levofloxacin, reach acceptable probability of target attainment rates when effluent rates of 20 or 35 mL/kg/h are used. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Validity of the Medical College Admission Test for predicting MD-PhD student outcomes.

PubMed

Bills, James L; VanHouten, Jacob; Grundy, Michelle M; Chalkley, Roger; Dermody, Terence S

2016-03-01

The Medical College Admission Test (MCAT) is a quantitative metric used by MD and MD-PhD programs to evaluate applicants for admission. This study assessed the validity of the MCAT in predicting training performance measures and career outcomes for MD-PhD students at a single institution. The study population consisted of 153 graduates of the Vanderbilt Medical Scientist Training Program (combined MD-PhD program) who matriculated between 1963 and 2003 and completed dual-degree training. This population was divided into three cohorts corresponding to the version of the MCAT taken at the time of application. Multivariable regression (logistic for binary outcomes and linear for continuous outcomes) was used to analyze factors associated with outcome measures. The MCAT score and undergraduate GPA (uGPA) were treated as independent variables; medical and graduate school grades, time-to-PhD defense, USMLE scores, publication number, and career outcome were dependent variables. For cohort 1 (1963-1977), MCAT score was not associated with any assessed outcome, although uGPA was associated with medical school preclinical GPA and graduate school GPA (gsGPA). For cohort 2 (1978-1991), MCAT score was associated with USMLE Step II score and inversely correlated with publication number, and uGPA was associated with preclinical GPA (mspGPA) and clinical GPA (mscGPA). For cohort 3 (1992-2003), the MCAT score was associated with mscGPA, and uGPA was associated with gsGPA. Overall, MCAT score and uGPA were inconsistent or weak predictors of training metrics and career outcomes for this population of MD-PhD students.

An evaluation of internal medicine residency continuity clinic redesign to a 50/50 outpatient-inpatient model.

PubMed

Wieland, Mark L; Halvorsen, Andrew J; Chaudhry, Rajeev; Reed, Darcy A; McDonald, Furman S; Thomas, Kris G

2013-08-01

There have been recent calls for improved internal medicine outpatient training, yet assessment of clinical and educational variables within existing models is lacking. To assess the impact of clinic redesign from a traditional weekly clinic model to a 50/50 outpatient-inpatient model on clinical and educational outcomes. Pre-intervention and post-intervention study intervals, comparing the 2009-2010 and 2010-2011 academic years. Ninety-six residents in a Primary Care Internal Medicine site of a large academic internal medicine residency program who provide care for > 13,000 patients. Continuity clinic redesign from a traditional weekly clinic model to a 50/50 model characterized by 50 % outpatient and 50 % inpatient experiences scheduled in alternating 1 month blocks, with twice weekly continuity clinic during outpatient months and no clinic during inpatient months. 1) Clinical outcomes (panel size, patient visits, adherence with chronic disease and preventive service guidelines, continuity of care, patient satisfaction, and perceived safety/teamwork in clinic); 2) Educational outcomes (attendance at teaching conference, resident and faculty satisfaction, faculty assessment of resident clinic performance, and residents' perceived preparedness for outpatient management). Redesign was associated with increased mean panel size (120 vs. 137.6; p ≤ 0.001), decreased continuity of care (63 % vs. 48 % from provider perspective; 61 % vs. 51 % from patient perspective; p ≤  0.001 for both; team continuity was preserved), decreased missed appointments (12.5 % vs. 10.9 %; p ≤  0.01), improved perceived safety and teamwork (3.6 vs. 4.1 on 5-point scale; p ≤  0.001), improved mean teaching conference attendance (57.1 vs. 64.4; p ≤  0.001), improved resident clinic performance (3.6 vs. 3.9 on 5-point scale; p ≤  0.001), and little change in other outcomes. Although this model requires further study in other settings, these results suggest that a 50/50 model may allow residents to manage more patients while enhancing the climate of teamwork and safety in the continuity clinic, compared to traditional models. Future work should explore ways to preserve continuity of care within this model.

Does external evaluation of laboratories improve patient safety?

PubMed

Noble, Michael A

2007-01-01

Laboratory accreditation and External Quality Assessment (also called proficiency testing) are mainstays of laboratory quality assessment and performance. Both practices are associated with examples of improved laboratory performance. The relationship between laboratory performance and improved patient safety is more difficult to assess because of the many variables that are involved with patient outcome. Despite this difficulty, the argument to continue external evaluation of laboratories is too compelling to consider the alternative.

Is the Prediction of Adolescent Outcomes from Early Child Care Moderated by Later Maternal Sensitivity? Results from the NICHD Study of Early Child Care and Youth Development

ERIC Educational Resources Information Center

Burchinal, Margaret R.; Lowe Vandell, Deborah; Belsky, Jay

2014-01-01

Longitudinal data are used to examine whether effects of early child care are amplified and/or attenuated by later parenting. Analyses tested these interactions using parenting as both a categorical and continuous variable to balance power and flexibility in testing moderation. The most consistent finding was that maternal sensitivity during…

Assessing the performance of the generalized propensity score for estimating the effect of quantitative or continuous exposures on survival or time-to-event outcomes.

PubMed

Austin, Peter C

2018-01-01

Propensity score methods are frequently used to estimate the effects of interventions using observational data. The propensity score was originally developed for use with binary exposures. The generalized propensity score (GPS) is an extension of the propensity score for use with quantitative or continuous exposures (e.g. pack-years of cigarettes smoked, dose of medication, or years of education). We describe how the GPS can be used to estimate the effect of continuous exposures on survival or time-to-event outcomes. To do so we modified the concept of the dose-response function for use with time-to-event outcomes. We used Monte Carlo simulations to examine the performance of different methods of using the GPS to estimate the effect of quantitative exposures on survival or time-to-event outcomes. We examined covariate adjustment using the GPS and weighting using weights based on the inverse of the GPS. The use of methods based on the GPS was compared with the use of conventional G-computation and weighted G-computation. Conventional G-computation resulted in estimates of the dose-response function that displayed the lowest bias and the lowest variability. Amongst the two GPS-based methods, covariate adjustment using the GPS tended to have the better performance. We illustrate the application of these methods by estimating the effect of average neighbourhood income on the probability of survival following hospitalization for an acute myocardial infarction.

Young adult educational and vocational outcomes of children diagnosed with ADHD.

PubMed

Kuriyan, Aparajita B; Pelham, William E; Molina, Brooke S G; Waschbusch, Daniel A; Gnagy, Elizabeth M; Sibley, Margaret H; Babinski, Dara E; Walther, Christine; Cheong, Jeewon; Yu, Jihnhee; Kent, Kristine M

2013-01-01

Decreased success at work and educational attainment by adulthood are of concern for children with ADHD given their widely documented academic difficulties; however there are few studies that have examined this empirically and even fewer that have studied predictors and individual variability of these outcomes. The current study compares young adults with and without a childhood diagnosis of ADHD on educational and occupational outcomes and the predictors of these outcomes. Participants were from the Pittsburgh ADHD Longitudinal Study (PALS), a prospective study with yearly data collection. Significant group differences were found for nearly all variables such that educational and occupational attainment was lower for adults with compared to adults without histories of childhood ADHD. Despite the mean difference, educational functioning was wide-ranging. High school academic achievement significantly predicted enrollment in post-high school education and academic and disciplinary problems mediated the relationship between childhood ADHD and post-high school education. Interestingly, ADHD diagnosis and disciplinary problems negatively predicted occupational status while enrollment in post-high school education was a positive predictor. Job loss was positively predicted by a higher rate of academic problems and diagnosis of ADHD. This study supports the need for interventions that target the child and adolescent predictors of later educational and occupational outcomes in addition to continuing treatment of ADHD in young adulthood targeting developmentally appropriate milestones, such as completing post-high school education and gaining and maintaining stable employment.

Status epilepticus in pregnancy: Etiology, management, and clinical outcomes.

PubMed

Rajiv, Keni Ravish; Radhakrishnan, Ashalatha

2017-11-01

Status epilepticus (SE) in pregnancy carries significant risk to both mother and fetus. There is limited literature available on SE occurring in pregnancy world-over, with majority being from obstetric centers. All women who developed SE related to pregnancy (gestation, labor, or puerperium) between January 2000 and December 2016 were included in the study. Data were collected from our SE registry, maintained, and archived in the institute. The variables influencing the maternal and fetal outcome were compared using Student's t-test for continuous variables and Fisher's exact test for discrete variables. During the 16-year study period, a total of 348 SE events were recorded in 294 patients. Among these, there were 138 women, of which 17 had SE related to pregnancy. The etiology of SE was remote symptomatic in two and acute symptomatic in 15 patients. The various causes detected after initial evaluation for acute symptomatic SE were eclampsia (n=4), posterior reversible encephalopathy syndrome due to various causes other than eclampsia (n=6), cortical venous thrombosis (n=3), subarachnoid hemorrhage (n=1), and NMDA receptor antibody-mediated encephalitis (n=1).13 of 17 women with SE (76%) had good outcome. Majority of the fetuses had good outcomes, i.e., Category 1 (n=9, 57%). Duration of intensive care unit stay (p=0.029) and Status Epilepticus Severity Score (p=0.0324) at admission, were found to be significantly associated with poor outcomes. In any patient presenting with SE occurring in pregnancy, though eclampsia is presumed to be the most common overall cause; it is relevant to consider other etiologies such as posterior reversible encephalopathy syndrome, cortical venous thrombosis, and autoimmune encephalitis especially in cases presenting with refractory SE. Posterior reversible encephalopathy may occur in pregnancy due to diverse etiologies other than eclampsia. Copyright © 2017 Elsevier Inc. All rights reserved.

Access to primary care for socio-economically disadvantaged older people in rural areas: exploring realist theory using structural equation modelling in a linked dataset.

PubMed

Ford, John A; Jones, Andy; Wong, Geoff; Clark, Allan; Porter, Tom; Steel, Nick

2018-06-19

Realist approaches seek to answer questions such as 'how?', 'why?', 'for whom?', 'in what circumstances?' and 'to what extent?' interventions 'work' using context-mechanism-outcome (CMO) configurations. Quantitative methods are not well-established in realist approaches, but structural equation modelling (SEM) may be useful to explore CMO configurations. Our aim was to assess the feasibility and appropriateness of SEM to explore CMO configurations and, if appropriate, make recommendations based on our access to primary care research. Our specific objectives were to map variables from two large population datasets to CMO configurations from our realist review looking at access to primary care, generate latent variables where needed, and use SEM to quantitatively test the CMO configurations. A linked dataset was created by merging individual patient data from the English Longitudinal Study of Ageing and practice data from the GP Patient Survey. Patients registered in rural practices and who were in the highest deprivation tertile were included. Three latent variables were defined using confirmatory factor analysis. SEM was used to explore the nine full CMOs. All models were estimated using robust maximum likelihoods and accounted for clustering at practice level. Ordinal variables were treated as continuous to ensure convergence. We successfully explored our CMO configurations, but analysis was limited because of data availability. Two hundred seventy-six participants were included. We found a statistically significant direct (context to outcome) or indirect effect (context to outcome via mechanism) for two of nine CMOs. The strongest association was between 'ease of getting through to the surgery' and 'being able to get an appointment' with an indirect mediated effect through convenience (proportion of the indirect effect of the total was 21%). Healthcare experience was not directly associated with getting an appointment, but there was a statistically significant indirect effect through convenience (53% mediated effect). Model fit indices showed adequate fit. SEM allowed quantification of CMO configurations and could complement other qualitative and quantitative techniques in realist evaluations to support inferences about strengths of relationships. Future research exploring CMO configurations with SEM should aim to collect, preferably continuous, primary data.

Systematic review and meta-analysis of Spanish studies regarding the association between maternal 25-hydroxyvitamin D levels and perinatal outcomes.

PubMed

Martínez-Domínguez, Samuel J; Tajada, Mauricio; Chedraui, Peter; Pérez-López, Faustino R

2018-05-29

This systematic review and meta-analysis of Spanish studies assessed the association of maternal 25-hydroxyvitamin D [25(OH)D] levels on perinatal outcomes. PubMed, Cochrane Library, Embase, Scielo, Scopus, and Web of Science research databases were searched from inception through December 30 2017 using the terms 'vitamin D', 'pregnancy', and 'Spain'. Studies that compared first or second half of pregnancy normal 25(OH)D (≥30.0 ng/mL) versus insufficient (20.0-29.9 ng/mL) or deficient (<20.0 ng/mL) circulating levels and perinatal outcomes were systematically extracted. Data are presented as pooled odds ratios and their 95% confidence intervals (CIs) for categorical variables or mean differences and CIs for continuous variables. Risk of bias was evaluated with the Newcastle-Ottawa Scale. Five cohort studies met inclusion criteria. The risk of gestational diabetes mellitus, preeclampsia, preterm birth, and small-for-gestational-age infants, and birthweight was not influenced by first half of pregnancy maternal 25(OH)D levels. In addition, second half of pregnancy 25(OH) levels did not affect birthweight. Maternal 25(OH)D levels during pregnancy did not affect studied perinatal outcomes and birthweight.

Motivation as an independent and a dependent variable in medical education: a review of the literature.

PubMed

Kusurkar, R A; Ten Cate, Th J; van Asperen, M; Croiset, G

2011-01-01

Motivation in learning behaviour and education is well-researched in general education, but less in medical education. To answer two research questions, 'How has the literature studied motivation as either an independent or dependent variable? How is motivation useful in predicting and understanding processes and outcomes in medical education?' in the light of the Self-determination Theory (SDT) of motivation. A literature search performed using the PubMed, PsycINFO and ERIC databases resulted in 460 articles. The inclusion criteria were empirical research, specific measurement of motivation and qualitative research studies which had well-designed methodology. Only studies related to medical students/school were included. Findings of 56 articles were included in the review. Motivation as an independent variable appears to affect learning and study behaviour, academic performance, choice of medicine and specialty within medicine and intention to continue medical study. Motivation as a dependent variable appears to be affected by age, gender, ethnicity, socioeconomic status, personality, year of medical curriculum and teacher and peer support, all of which cannot be manipulated by medical educators. Motivation is also affected by factors that can be influenced, among which are, autonomy, competence and relatedness, which have been described as the basic psychological needs important for intrinsic motivation according to SDT. Motivation is an independent variable in medical education influencing important outcomes and is also a dependent variable influenced by autonomy, competence and relatedness. This review finds some evidence in support of the validity of SDT in medical education.

A diabetes-specific enteral formula improves glycemic variability in patients with type 2 diabetes.

PubMed

Alish, Carolyn J; Garvey, W Timothy; Maki, Kevin C; Sacks, Gordon S; Hustead, Deborah S; Hegazi, Refaat A; Mustad, Vikkie A

2010-06-01

Well-controlled studies have demonstrated that inpatient hyperglycemia is an indicator of poor clinical outcomes, but the use of diabetes-specific enteral formulas in hospitalized patients remains a topic of great debate. In two different protocols, postprandial glycemia and insulinemia were measured in 22 subjects with diabetes fed a diabetes-specific or standard formula (protocol 1). Continuous glucose monitoring was used to assess glucose levels in 12 enterally fed patients with diabetes receiving the standard formula followed by the diabetes-specific formula continuously for 5 days each (protocol 2). End points included postprandial glycemia and insulinemia, glycemic variability (mean amplitude of glycemic excursions [MAGE]), mean glucose, and insulin use. In the postprandial response protocol, the diabetes-specific formula resulted in lower positive areas under the postprandial curve (P < 0.001) and peak glucose (P < 0.001) and insulin (P = 0.017) levels. In the protocol using continuous glucose monitoring, glycemic variability (as measured by MAGE) was lower with continuous administration of the diabetes-specific than the standard formula (64.6 +/- 6.8 mg/dL vs. 110.6 +/-15.3 mg/dL, P = 0.003). Also, administration of the diabetes-specific formula resulted in lower mean glucose concentrations during feeding (171.1 +/- 16.1 vs. 202.1 +/- 17.4 mg/dL, P = 0.024) and insulin requirements (7.8 +/- 2.3 vs. 10.9 +/- 3.3 units/day, P = 0.039) than the standard formula. Relative to the standard formula, the diabetes-specific formula reduced postprandial glycemia, mean glucose, glycemic variability, and short-acting insulin requirements. These results suggest potential clinical usefulness of a diabetes-specific enteral formula for minimizing glycemic excursions in hospitalized patients.

Patient characteristics and variability in adherence and competence in cognitive-behavioral therapy for panic disorder.

PubMed

Boswell, James F; Gallagher, Matthew W; Sauer-Zavala, Shannon E; Bullis, Jacqueline; Gorman, Jack M; Shear, M Katherine; Woods, Scott; Barlow, David H

2013-06-01

Although associations with outcome have been inconsistent, therapist adherence and competence continues to garner attention, particularly within the context of increasing interest in the dissemination, implementation, and sustainability of evidence-based treatments. To date, research on therapist adherence and competence has focused on average levels across therapists. With a few exceptions, research has failed to address multiple sources of variability in adherence and competence, identify important factors that might account for variability, or take these sources of variability into account when examining associations with symptom change. (a) statistically demonstrate between- and within-therapist variability in adherence and competence ratings and examine patient characteristics as predictors of this variability and (b) examine the relationship between adherence/competence and symptom change. Randomly selected audiotaped sessions from a randomized controlled trial of cognitive-behavioral therapy for panic disorder were rated for therapist adherence and competence. Patients completed a self-report measure of panic symptom severity prior to each session and the Inventory of Interpersonal Problems-Personality Disorder Scale prior to the start of treatment. Significant between- and within-therapist variability in adherence and competence were observed. Adherence and competence deteriorated significantly over the course of treatment. Higher patient interpersonal aggression was associated with decrements in both adherence and competence. Neither adherence nor competence predicted subsequent panic severity. Variability and "drift" in adherence and competence can be observed in controlled trials. Training and implementation efforts should involve continued consultation over multiple cases in order to account for relevant patient factors and promote sustainability across sessions and patients.

Long-term follow-up of cognitive functions in patients with continuous spike-waves during sleep (CSWS).

PubMed

Maltoni, Lucia; Posar, Annio; Parmeggiani, Antonia

2016-07-01

Continuous spike-waves during sleep (CSWS) are associated with several cognitive, neurological, and psychiatric disorders, which sometimes persist after CSWS disappearance. The purpose of this retrospective study was to investigate the correlation between general (clinical and instrumental) and neuropsychological findings in CSWS, to identify variables that predispose patients to a poorer long-term neuropsychological outcome. Patients with spikes and waves during sleep with a frequency ≥25/min (spikes and waves frequency index - SWFI) were enrolled. There were patients presenting abnormal EEG activity corresponding to the classic CSWS and patients with paroxysmal abnormalities during sleep <85% with SWFI ≥25/min that was defined as excessive spike-waves during sleep (ESWS). Clinical and instrumental features and neuropsychological findings during and after the spike and wave active phase period were considered. A statistical analysis was performed utilizing the Spearman correlation test and multivariate analysis. The study included 61 patients; the mean follow-up (i.e., the period between SWFI ≥25 first recording and last observation) was 7years and 4months. The SWFI correlated inversely with full and performance IQ during CSWS/ESWS. Longer-lasting SWFI ≥25 was related to worse results in verbal IQ and performance IQ after CSWS/ESWS disappearance. Other variables may influence the neuropsychological outcome, like age at SWFI ≥25 first recording, perinatal distress, pathologic neurologic examination, and antiepileptic drug resistance. This confirms that CSWS/ESWS are a complex pathology and that many variables contribute to its outcome. The SWFI value above all during CSWS/ESWS and long-lasting SWFI ≥25 after CSWS/ESWS disappearance are the most significant indexes that appear mostly to determine cognitive evolution. This finding underscores the importance of EEG recordings during sleep in children with a developmental disorder, even if seizures are not reported, as well as the importance of using therapy with an early efficacy. Copyright © 2016 Elsevier Inc. All rights reserved.

How valid are self-reports of illness-related absence? Evidence from a university employee health management program.

PubMed

Jenkins, Kristi Rahrig

2014-08-01

The present study uses a focused approach to compare self-reported versus administratively recorded measures of absences related to health or illness. To date, the few studies that focus on this topic produced mixed results. To help shed light on this issue, the present research has 2 related objectives: (1) examine how highly correlated self-reported and administratively recorded measures of absences related to health or illness might be, and (2) how each measure predicts various aspects of health. Using data from the 2012 StayWell® Health Management health risk appraisal (HRA) and 1 year (2011) of administratively recorded timekeeping data, bivariate analyses for continuous variables and generalized linear modeling for variables with greater than 2 response categories were used. For the multivariate analyses, linear regression models controlling for sex, age, race, income, job status, and campus location were calculated for the continuous outcomes (ie, self-rated health and chronic conditions). Results indicate that self-reported and administratively recorded absences related to health or illness were moderately correlated (correlation coefficient of 0.47). In addition, each measure functioned similarly (in direction and magnitude) to predict health outcomes. Both greater self-reported and recorded illness-related absenteeism was associated with poorer self-rated health and greater numbers of chronic conditions. These results suggest that self-rated illness-related absenteeism may be a reasonable way to assess various program outcomes meaningful to employers, particularly if administratively recorded measures are unavailable or too time consuming or expensive to analyze.

Poverty, Pregnancy, and Birth Outcomes: A Study of the Earned Income Tax Credit

PubMed Central

Rehkopf, David H.

2015-01-01

Background Economic interventions are increasingly recognized as a mechanism to address perinatal health outcomes among disadvantaged groups. In the United States, the earned income tax credit (EITC) is the largest poverty alleviation program. Little is known about its effects on perinatal health among recipients and their children. We exploit quasi-random variation in the size of EITC payments over time to examine the effects of income on perinatal health. Methods The study sample includes women surveyed in the 1979 National Longitudinal Survey of Youth (N=2,985) and their children born during 1986–2000 (N=4,683). Outcome variables include utilization of prenatal and postnatal care, use of alcohol and tobacco during pregnancy, term birth, birthweight, and breast-feeding status. We examine the health effects of both household income and EITC payment size using multivariable linear regressions. We employ instrumental variables analysis to estimate the causal effect of income on perinatal health, using EITC payment size as an instrument for household income. Results We find that household income and EITC payment size are associated with improvements in several indicators of perinatal health. Instrumental variables analysis, however, does not reveal a causal association between household income and these health measures. Conclusions Our findings suggest that associations between income and perinatal health may be confounded by unobserved characteristics, but that EITC income improves perinatal health. Future studies should continue to explore the impacts of economic interventions on perinatal health outcomes, and investigate how different forms of income transfers may have different impacts. PMID:26212041

Genetic variation in alpha2-adrenoreceptors and heart rate recovery after exercise

PubMed Central

Kohli, Utkarsh; Diedrich, André; Kannankeril, Prince J.; Muszkat, Mordechai; Sofowora, Gbenga G.; Hahn, Maureen K.; English, Brett A.; Blakely, Randy D.; Stein, C. Michael

2015-01-01

Heart rate recovery (HRR) after exercise is an independent predictor of adverse cardiovascular outcomes. HRR is mediated by both parasympathetic reactivation and sympathetic withdrawal and is highly heritable. We examined whether common genetic variants in adrenergic and cholinergic receptors and transporters affect HRR. In our study 126 healthy subjects (66 Caucasians, 56 African Americans) performed an 8 min step-wise bicycle exercise test with continuous computerized ECG recordings. We fitted an exponential curve to the postexercise R-R intervals for each subject to calculate the recovery constant (kr) as primary outcome. Secondary outcome was the root mean square residuals averaged over 1 min (RMS1min), a marker of parasympathetic tone. We used multiple linear regressions to determine the effect of functional candidate genetic variants in autonomic pathways (6 ADRA2A, 1 ADRA2B, 4 ADRA2C, 2 ADRB1, 3 ADRB2, 2 NET, 2 CHT, and 1 GRK5) on the outcomes before and after adjustment for potential confounders. Recovery constant was lower (indicating slower HRR) in ADRA2B 301–303 deletion carriers (n = 54, P = 0.01), explaining 3.6% of the interindividual variability in HRR. ADRA2A Asn251Lys, ADRA2C rs13118771, and ADRB1 Ser49Gly genotypes were associated with RMS1min. Genetic variability in adrenergic receptors may be associated with HRR after exercise. However, most of the interindividual variability in HRR remained unexplained by the variants examined. Noncandidate gene-driven approaches to study genetic contributions to HRR in larger cohorts will be of interest. PMID:26058836

Final Report for Dynamic Models for Causal Analysis of Panel Data. Models for Change in Quantitative Variables, Part I Deterministic Models. Part II, Chapter 3.

ERIC Educational Resources Information Center

Hannan, Michael T.

This document is part of a series of chapters described in SO 011 759. Addressing the question of effective models to measure change and the change process, the author suggests that linear structural equation systems may be viewed as steady state outcomes of continuous-change models and have rich sociological grounding. Two interpretations of the…

Long-term outcome and prognostic factors of juvenile dermatomyositis: a multinational, multicenter study of 490 patients.

PubMed

Ravelli, Angelo; Trail, Lucia; Ferrari, Cristina; Ruperto, Nicolino; Pistorio, Angela; Pilkington, Clarissa; Maillard, Susan; Oliveira, Sheila K; Sztajnbok, Flavio; Cuttica, Ruben; Beltramelli, Matilde; Corona, Fabrizia; Katsicas, Maria Martha; Russo, Ricardo; Ferriani, Virginia; Burgos-Vargas, Ruben; Magni-Manzoni, Silvia; Solis-Valleoj, Eunice; Bandeira, Marcia; Zulian, Francesco; Baca, Vicente; Cortis, Elisabetta; Falcini, Fernanda; Alessio, Maria; Alpigiani, Maria Giannina; Gerloni, Valeria; Saad-Magalhaes, Claudia; Podda, Rosanna; Silva, Clovis A; Lepore, Loredana; Felici, Enrico; Rossi, Federica; Sala, Elena; Martini, Alberto

2010-01-15

To investigate the long-term outcome and prognostic factors of juvenile dermatomyositis (DM) through a multinational, multicenter study. Patients consisted of inception cohorts seen between 1980 and 2004 in 27 centers in Europe and Latin America. Predictor variables were sex, continent, ethnicity, onset year, onset age, onset type, onset manifestations, course type, disease duration, and active disease duration. Outcomes were muscle strength/endurance, continued disease activity, cumulative damage, muscle damage, cutaneous damage, calcinosis, lipodystrophy, physical function, and health-related quality of life (HRQOL). A total of 490 patients with a mean disease duration of 7.7 years were included. At the cross-sectional visit, 41.2-52.8% of patients, depending on the instrument used, had reduced muscle strength/endurance, but less than 10% had severe impairment. Persistently active disease was recorded in 41.2-60.5% of the patients, depending on the activity measure used. Sixty-nine percent of the patients had cumulative damage. The frequency of calcinosis and lipodystrophy was 23.6% and 9.7%, respectively. A total of 40.7% of the patients had decreased functional ability, but only 6.5% had major impairment. Only a small fraction had decreased HRQOL. A chronic course, either polycyclic or continuous, consistently predicted a poorer outcome. Mortality rate was 3.1%. This study confirms the marked improvement in functional outcome of juvenile DM when compared with earlier literature. However, many patients had continued disease activity and cumulative damage at followup. A chronic course was the strongest predictor of poor prognosis. These findings highlight the need for treatment strategies that enable a better control of disease activity over time and the reduction of nonreversible damage.

Assessing the performance of the generalized propensity score for estimating the effect of quantitative or continuous exposures on binary outcomes

PubMed Central

2018-01-01

Propensity score methods are increasingly being used to estimate the effects of treatments and exposures when using observational data. The propensity score was initially developed for use with binary exposures. The generalized propensity score (GPS) is an extension of the propensity score for use with quantitative or continuous exposures (eg, dose or quantity of medication, income, or years of education). We used Monte Carlo simulations to examine the performance of different methods of using the GPS to estimate the effect of continuous exposures on binary outcomes. We examined covariate adjustment using the GPS and weighting using weights based on the inverse of the GPS. We examined both the use of ordinary least squares to estimate the propensity function and the use of the covariate balancing propensity score algorithm. The use of methods based on the GPS was compared with the use of G‐computation. All methods resulted in essentially unbiased estimation of the population dose‐response function. However, GPS‐based weighting tended to result in estimates that displayed greater variability and had higher mean squared error when the magnitude of confounding was strong. Of the methods based on the GPS, covariate adjustment using the GPS tended to result in estimates with lower variability and mean squared error when the magnitude of confounding was strong. We illustrate the application of these methods by estimating the effect of average neighborhood income on the probability of death within 1 year of hospitalization for an acute myocardial infarction. PMID:29508424

Assessing the performance of the generalized propensity score for estimating the effect of quantitative or continuous exposures on binary outcomes.

PubMed

Austin, Peter C

2018-05-20

Propensity score methods are increasingly being used to estimate the effects of treatments and exposures when using observational data. The propensity score was initially developed for use with binary exposures. The generalized propensity score (GPS) is an extension of the propensity score for use with quantitative or continuous exposures (eg, dose or quantity of medication, income, or years of education). We used Monte Carlo simulations to examine the performance of different methods of using the GPS to estimate the effect of continuous exposures on binary outcomes. We examined covariate adjustment using the GPS and weighting using weights based on the inverse of the GPS. We examined both the use of ordinary least squares to estimate the propensity function and the use of the covariate balancing propensity score algorithm. The use of methods based on the GPS was compared with the use of G-computation. All methods resulted in essentially unbiased estimation of the population dose-response function. However, GPS-based weighting tended to result in estimates that displayed greater variability and had higher mean squared error when the magnitude of confounding was strong. Of the methods based on the GPS, covariate adjustment using the GPS tended to result in estimates with lower variability and mean squared error when the magnitude of confounding was strong. We illustrate the application of these methods by estimating the effect of average neighborhood income on the probability of death within 1 year of hospitalization for an acute myocardial infarction. © 2018 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

[Near miss outcomes in gambling games].

PubMed

Pecsenye, Zsuzsa; Kurucz, Gyozo

2017-01-01

Games of chance operate with an intermittent reinforcement schedule in which the number of games takes the player to win differ in each turn thus they can not predict when the next positive reinforcement arrives. The near miss outcome (close to winning but actually a losing outcome) can be interpreted as a secondary (built in) reinforcement within variable ratio reinforcement schedule that presumably contribute to the development and maintanance of gambling addiction. The aim of this publication would be to introduce near miss outcomes and to summarize and critically analyze literature connected to this issue.We searched internet datebases using word "near miss" and analyse articles focusing on gambling games. Based on numerous authors' results a near miss rate set at around 30% increases the desire to continue playing among gamblers and players who have no former gambling experience as well. Some studies have demonstrated that this effect might be related to the extent the player has the situation under control during the gambling session. The hypothetical inhibiting effect of a 45% near miss ratio has not yet been proven. Neurobiological researches show middle-cerebral activity during near miss outcomes furthermore similar physiological patterns have been discovered following a near miss and winning outcomes. Regarding the connection between intrapsychic variables (cognitive and personality factors) and near misses there are very few studies. The fact that different authors interpret near miss outcomes differently even when studying the same game leads to problems in interpreting their results. It follows from the foregoing empirical results that near miss outcomes contribute to the development and maintanance of pathological gambling but we have little information on the factors implementing this effect.

Social outcomes in mid- to later adulthood among individuals diagnosed with autism and average nonverbal IQ as children.

PubMed

Howlin, Patricia; Moss, Philippa; Savage, Sarah; Rutter, Michael

2013-06-01

To describe current social functioning in a clinical sample of 60 adults with autism (mean age = 44 years) who were all of average nonverbal IQ (70+) when first diagnosed (mean age = 6.75 years). Outcome measures included standardized diagnostic and cognitive assessments and questionnaires on social functioning. Child and adult variables related to current outcomes were explored. All individuals continued to meet criteria for autism spectrum disorder (ASD) on the Autism Diagnostic Interview-Revised (ADI-R), but severity of autism symptoms declined over time. Nevertheless, only 10 individuals (17%) were rated as having a "good" or "very good" outcome; the majority (60%) were assessed as having "poor" or "very poor" outcomes. The strongest predictor of adult outcome was the Reciprocal Social Interaction domain score on the ADI at diagnostic confirmation. Change over time was further examined in a subgroup (n = 44) previously assessed 20 years ago earlier (mean age = 26 years). Although severity of autism had continued to decrease during the adult period, social outcomes were poorer than in younger adulthood. In this cohort of adults first diagnosed with autism, on average, 37 years previously, social inclusion remains very limited, despite general improvements in autism symptomatology with age. Whether these findings will be replicated in future generations of children with autism, who now have the benefits of earlier diagnosis and wider access to specialist provision, needs to be the focus of further longitudinal research. Copyright © 2013 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Interpreting the concordance statistic of a logistic regression model: relation to the variance and odds ratio of a continuous explanatory variable

PubMed Central

2012-01-01

Background When outcomes are binary, the c-statistic (equivalent to the area under the Receiver Operating Characteristic curve) is a standard measure of the predictive accuracy of a logistic regression model. Methods An analytical expression was derived under the assumption that a continuous explanatory variable follows a normal distribution in those with and without the condition. We then conducted an extensive set of Monte Carlo simulations to examine whether the expressions derived under the assumption of binormality allowed for accurate prediction of the empirical c-statistic when the explanatory variable followed a normal distribution in the combined sample of those with and without the condition. We also examine the accuracy of the predicted c-statistic when the explanatory variable followed a gamma, log-normal or uniform distribution in combined sample of those with and without the condition. Results Under the assumption of binormality with equality of variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the product of the standard deviation of the normal components (reflecting more heterogeneity) and the log-odds ratio (reflecting larger effects). Under the assumption of binormality with unequal variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the standardized difference of the explanatory variable in those with and without the condition. In our Monte Carlo simulations, we found that these expressions allowed for reasonably accurate prediction of the empirical c-statistic when the distribution of the explanatory variable was normal, gamma, log-normal, and uniform in the entire sample of those with and without the condition. Conclusions The discriminative ability of a continuous explanatory variable cannot be judged by its odds ratio alone, but always needs to be considered in relation to the heterogeneity of the population. PMID:22716998

Naltrexone and Cognitive Behavioral Therapy for the Treatment of Alcohol Dependence

PubMed Central

Baros, AM; Latham, PK; Anton, RF

2008-01-01

Background Sex differences in regards to pharmacotherapy for alcoholism is a topic of concern following publications suggesting naltrexone, one of the longest approved treatments of alcoholism, is not as effective in women as in men. This study was conducted by combining two randomized placebo controlled clinical trials utilizing similar methodologies and personnel in which the data was amalgamated to evaluate sex effects in a reasonable sized sample. Methods 211 alcoholics (57 female; 154 male) were randomized to the naltrexone/CBT or placebo/CBT arm of the two clinical trials analyzed. Baseline variables were examined for differences between sex and treatment groups via analysis of variance (ANOVA) for continuous variable or chi-square test for categorical variables. All initial outcome analysis was conducted under an intent-to-treat analysis plan. Effect sizes for naltrexone over placebo were determined by Cohen’s D (d). Results The effect size of naltrexone over placebo for the following outcome variables was similar in men and women (%days abstinent (PDA) d=0.36, %heavy drinking days (PHDD) d=0.36 and total standard drinks (TSD) d=0.36). Only for men were the differences significant secondary to the larger sample size (PDA p=0.03; PHDD p=0.03; TSD p=0.04). There were a few variables (GGT at wk-12 change from baseline to week-12: men d=0.36, p=0.05; women d=0.20, p=0.45 and drinks per drinking day: men d=0.36, p=0.05; women d=0.28, p=0.34) where the naltrexone effect size for men was greater than women. In women, naltrexone tended to increase continuous abstinent days before a first drink (women d-0.46, p=0.09; men d=0.00, p=0.44). Conclusions The effect size of naltrexone over placebo appeared similar in women and men in our hands suggesting the findings of sex differences in naltrexone response might have to do with sample size and/or endpoint drinking variables rather than any inherent pharmacological or biological differences in response. PMID:18336635

Elective neck dissection for primary oral cavity squamous cell carcinoma involving the tongue should include sublevel IIb.

PubMed

Maher, Nigel Gordon; Hoffman, Gary Russell

2014-11-01

The surgical clearance of sublevel IIb lymph nodes, facilitated by neck dissection, increases the risk of postoperative shoulder dysfunction. Our study purpose was to determine the value of including sublevel IIb in elective neck dissections for primary oral cavity squamous cell carcinoma (OCSCC). A retrospective cohort study based on a review of the pathology records accumulated by 1 head and neck surgeon was conducted for 71 patients with clinically node-negative, primary OCSCC treated from 2006 to June 2013. The predictor variables were the oral cavity subsite and tumor clinicopathologic characteristics (ie, perineural, perivascular, and perilymphatic invasion, tumor depth, and T stage). The primary outcome variable was the presence of sublevel IIb metastasis. The secondary outcome variables were the survival and tumor recurrence rates and metastases to any cervical level. Descriptive statistics were calculated for the categorical and continuous variables. A comparison of categorical variables was performed using Fisher's exact test; for continuous variables, t tests or the Mann-Whitney U test were used for 2 groups and analysis of variance or Kruskal-Wallis tests (with Bonferroni's correction) were used for more than 2 groups, depending on the distribution. Disease-specific survival (DSS) analyses were plotted for the predictor variables and patients with sublevel IIb metastasis. Competing risks models were created using the Fine and Gray method (SAS macro %PSHREG) to provide estimates of the crude and adjusted subhazard ratios for DSS for all variables. A total of 71 patients were included in the present study, of whom 69% were male. The greatest proportion of oral cavity subsites was from the tongue and floor of mouth. The overall frequency of sublevel IIb lymphatic metastases at neck dissection was 5.6% of the patient cohort. Sublevel IIb metastases occurred from the primary sites involving the tongue (n = 3) and retromolar trigone (n = 1). The incidence of perilymphatic and perivascular invasion was significantly associated with sublevel IIb lymphatic metastases (P < .02). Sublevel IIb is likely to be an important region to incorporate in elective neck dissections for primary OCSCC involving the tongue. More studies are needed, with greater numbers, to clarify the risk of metastasis to sublevel IIb from oral cavity subsites in primary OCSCC with clinically node-negative necks. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Effects of a Cancer Prevention Advertisement on Beliefs and Knowledge about Cancer Prevention.

PubMed

Kye, Su Yeon; Yoo, Jisu; Lee, Min Hee; Jun, Jae Kwan

2015-01-01

Outcome-expectation beliefs and knowledge may ultimately influence behavior for cancer prevention. The aims of this study were to measure changes in knowledge and beliefs about cancer prevention before and after viewing a television advertisement and identify the factors affecting receptivity to its messages. A one-group pretest-posttest design was used in this study of 1,000 individuals aged 20 to 65 years who were recruited online in November 2014. The outcome variables included cancer prevention beliefs based on the Health Belief Model (five items) and knowledge about risk factors for cancer (seven items). Perceived susceptibility, perceived benefits, and self-efficacy increased significantly and their perceived severity and perceived barriers decreased significantly, after participants viewed the television advertisement. Correct responses to questions about risk factors also increased significantly, except for smoking. The main factors affecting changes in the outcome variables were age, interest in cancer prevention, social network, satisfaction with the ad, and pretest scores. Television advertisements with positive frameworks can be an efficient channel of improving beliefs and knowledge about cancer prevention in a short period. The continuous development of intervention materials that consider the demographics, needs, and satisfaction of the target group will be necessary for future studies.

A survival tree method for the analysis of discrete event times in clinical and epidemiological studies.

PubMed

Schmid, Matthias; Küchenhoff, Helmut; Hoerauf, Achim; Tutz, Gerhard

2016-02-28

Survival trees are a popular alternative to parametric survival modeling when there are interactions between the predictor variables or when the aim is to stratify patients into prognostic subgroups. A limitation of classical survival tree methodology is that most algorithms for tree construction are designed for continuous outcome variables. Hence, classical methods might not be appropriate if failure time data are measured on a discrete time scale (as is often the case in longitudinal studies where data are collected, e.g., quarterly or yearly). To address this issue, we develop a method for discrete survival tree construction. The proposed technique is based on the result that the likelihood of a discrete survival model is equivalent to the likelihood of a regression model for binary outcome data. Hence, we modify tree construction methods for binary outcomes such that they result in optimized partitions for the estimation of discrete hazard functions. By applying the proposed method to data from a randomized trial in patients with filarial lymphedema, we demonstrate how discrete survival trees can be used to identify clinically relevant patient groups with similar survival behavior. Copyright © 2015 John Wiley & Sons, Ltd.

Bilingualism: A Pearl to Overcome Certain Perils of Cochlear Implants

PubMed Central

Humphries, Tom; Kushalnagar, Poorna; Mathur, Gaurav; Napoli, Donna Jo; Padden, Carol; Rathmann, Christian; Smith, Scott

2014-01-01

Cochlear implants (CI) have demonstrated success in improving young deaf children’s speech and low-level speech awareness across a range of auditory functions, but this success is highly variable, and how this success correlates to high-level language development is even more variable. Prevalence on the success rate of CI as an outcome for language development is difficult to obtain because studies vary widely in methodology and variables of interest, and because not all cochlear implant technology (which continues to evolve) is the same. Still, even if the notion of treatment failure is limited narrowly to those who gain no auditory benefit from CI in that they cannot discriminate among ambient noises, the reported treatment failure rate is high enough to call into question the current lack of consideration of alternative approaches to ensure young deaf children’s language development. Recent research has highlighted the risks of delaying language input during critical periods of brain development with concomitant consequences for cognitive and social skills. As a result, we propose that before, during, and after implantation deaf children learn a sign language along with a spoken language to ensure their maximal language development and optimal long-term developmental outcomes. PMID:25419095

Incorporating nonlinearity into mediation analyses.

PubMed

Knafl, George J; Knafl, Kathleen A; Grey, Margaret; Dixon, Jane; Deatrick, Janet A; Gallo, Agatha M

2017-03-21

Mediation is an important issue considered in the behavioral, medical, and social sciences. It addresses situations where the effect of a predictor variable X on an outcome variable Y is explained to some extent by an intervening, mediator variable M. Methods for addressing mediation have been available for some time. While these methods continue to undergo refinement, the relationships underlying mediation are commonly treated as linear in the outcome Y, the predictor X, and the mediator M. These relationships, however, can be nonlinear. Methods are needed for assessing when mediation relationships can be treated as linear and for estimating them when they are nonlinear. Existing adaptive regression methods based on fractional polynomials are extended here to address nonlinearity in mediation relationships, but assuming those relationships are monotonic as would be consistent with theories about directionality of such relationships. Example monotonic mediation analyses are provided assessing linear and monotonic mediation of the effect of family functioning (X) on a child's adaptation (Y) to a chronic condition by the difficulty (M) for the family in managing the child's condition. Example moderated monotonic mediation and simulation analyses are also presented. Adaptive methods provide an effective way to incorporate possibly nonlinear monotonicity into mediation relationships.

Acute lymphoblastic leukemia in adolescents and young adults.

PubMed

Ribera, Josep-Maria; Oriol, Albert

2009-10-01

Today, long-term survival is achieved in more than 80% of children 1 to 10 years old with acute lymphoblastic leukemia (ALL). However, cure rates for adults and adolescents and young adults (AYA) with ALL remain relatively low, at only 40% to 50%. Age is a continuous prognostic variable in ALL, with no single age at which prognosis deteriorates markedly. Within childhood ALL populations, older children have shown inferior outcomes, whereas younger adults have shown superior outcomes among adult ALL patients. The type of treatment (pediatric-based versus adult-based) for AYA has recently been a matter of debate. In this article the biology and treatment of ALL in AYA is reviewed.

Noise and hand-arm vibration exposure in relation to the risk of hearing loss.

PubMed

Pettersson, Hans; Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr

2012-01-01

The aim of this study was to examine the possible association of combined exposure of noise and hand-arm vibration (HAV) and the risk of noise-induced hearing loss. Workers in a heavy engineering industry were part of a dynamic cohort. Of these workers, 189 had HAV exposure, and their age and hearing status were recorded in the same year and were, therefore, included in the analysis. Data on HAV duration and acceleration was gathered through questionnaires, observations, and measurements. All available audiograms were categorized into normal and hearing loss. The first exposure variable included the lifetime HAV exposure. The lifetime HAV exposure was multiplied by the acceleration of HAV for the second and third exposure variable. Logistic regression using the Generalized Estimation Equations method was chosen to analyze the data to account for the repeated measurements. The analysis was performed with both continuous exposure variables and with exposure variables grouped into exposure quartiles with hearing loss as an outcome and age as a covariate. With continuous exposure variables, the odds ratio (OR) with a 95% confidence interval (CI) for hearing loss was equal to or greater than one for all exposure variables. When the exposure variables were grouped into quartiles, the OR with a 95% CI was greater than one at the third and fourth quartile. The results show that working with vibrating machines in an environment with noise exposure increases the risk of hearing loss, supporting an association between exposure to noise and HAV, and the noise-induced hearing loss.

Young Adult Educational and Vocational Outcomes of Children Diagnosed with ADHD

PubMed Central

Kuriyan, Aparajita B.; Pelham, William E.; Molina, Brooke S. G.; Waschbusch, Daniel A.; Gnagy, Elizabeth M.; Sibley, Margaret H.; Babinski, Dara E.; Walther, Christine; Cheong, JeeWon; Yu, Jihnhee; Kent, Kristine M.

2012-01-01

Decreased success at work and educational attainment by adulthood are of concern for children with ADHD given their widely documented academic difficulties; however there are few studies that have examined this empirically and even fewer that have studied predictors and individual variability of these outcomes. The current study compares young adults with and without a childhood diagnosis of ADHD on educational and occupational outcomes and the predictors of these outcomes. Participants were from the Pittsburgh ADHD Longitudinal Study (PALS), a prospective study with yearly data collection. Significant group differences were found for nearly all variables such that educational and occupational attainment was lower for adults with compared to adults without histories of childhood ADHD. Despite the mean difference, educational functioning was wide-ranging. High school academic achievement significantly predicted enrollment in post-high school education and academic and disciplinary problems mediated the relationship between childhood ADHD and post-high school education. Interestingly, ADHD diagnosis and disciplinary problems negatively predicted occupational status while enrollment in post-high school education was a positive predictor. Job loss was positively predicted by a higher rate of academic problems and diagnosis of ADHD. This study supports the need for interventions that target the child and adolescent predictors of later educational and occupational outcomes in addition to continuing treatment of ADHD in young adulthood targeting developmentally appropriate milestones, such as completing post-high school education and gaining and maintaining stable employment. PMID:22752720

Web-based questionnaires to assess perinatal outcome proved to be valid.

PubMed

van Gelder, Marleen M H J; Vorstenbosch, Saskia; Derks, Lineke; Te Winkel, Bernke; van Puijenbroek, Eugène P; Roeleveld, Nel

2017-10-01

The objective of this study was to validate a Web-based questionnaire completed by the mother to assess perinatal outcome used in a prospective cohort study. For 882 women with an estimated date of delivery between February 2012 and February 2015 who participated in the PRegnancy and Infant DEvelopment (PRIDE) Study, we compared data on pregnancy outcome, including mode of delivery, plurality, gestational age, birth weight and length, head circumference, birth defects, and infant sex, from Web-based questionnaires administered to the mothers 2 months after delivery with data from obstetric records. For continuous variables, we calculated intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs), whereas sensitivity and specificity were determined for categorical variables. We observed only very small differences between the two methods of data collection for gestational age (ICC, 0.91; 95% CI, 0.90-0.92), birth weight (ICC, 0.96; 95% CI, 0.95-0.96), birth length (ICC, 0.90; 95% CI, 0.87-0.92), and head circumference (ICC, 0.88; 95% CI, 0.80-0.93). Agreement between the Web-based questionnaire and obstetric records was high as well, with sensitivity ranging between 0.86 (termination of pregnancy) and 1.00 (four outcomes) and specificity between 0.96 (term birth) and 1.00 (nine outcomes). Our study provides evidence that Web-based questionnaires could be considered as a valid complementary or alternative method of data collection. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiology, intervention, and outcome: three critical questions about cerebral tissue oxygen saturation monitoring.

PubMed

Meng, Lingzhong; Gruenbaum, Shaun E; Dai, Feng; Wang, Tianlong

2018-05-01

The balance between cerebral tissue oxygen consumption and supply can be continuously assessed by cerebral tissue oxygen saturation (SctO2) monitor. A construct consisting of three sequential questions, targeting the physiology monitored, the intervention implemented, and the outcomes affected, is proposed to critically appraise this monitor. The impact of the SctO2-guided care on patient outcome was examined through a systematic literature search and meta-analysis. We concluded that the physiology monitored by SctO2 is robust and dynamic, fragile (prone to derangement), and adversely consequential when deranged. The inter-individual variability of SctO2 measurement advocates for an intervention threshold based on a relative, not absolute, change. The intra-individual variability has multiple determinants which is the foundation of intervention. A variety of therapeutic options are available; however, none are 100% efficacious in treating cerebral dys-oxygenation. The therapeutic efficacy likely depends on both an appropriate differential diagnosis and the functional status of the regulatory mechanisms of cerebral blood flow. Meta-analysis based on five randomized controlled trials suggested a reduced incidence of early postoperative cognitive decline after major surgeries (RR= 0.53; 95% CI: 0.33-0.87; I2 =82%; P=0.01). However, its effects on other neurocognitive outcomes remain unclear. These results need to be interpreted with caution due to the high risks of bias. Quality RCTs based on improved intervention protocols and standardized outcome assessment are warranted in the future.

High statistical heterogeneity is more frequent in meta-analysis of continuous than binary outcomes.

PubMed

Alba, Ana C; Alexander, Paul E; Chang, Joanne; MacIsaac, John; DeFry, Samantha; Guyatt, Gordon H

2016-02-01

We compared the distribution of heterogeneity in meta-analyses of binary and continuous outcomes. We searched citations in MEDLINE and Cochrane databases for meta-analyses of randomized trials published in 2012 that reported a measure of heterogeneity of either binary or continuous outcomes. Two reviewers independently performed eligibility screening and data abstraction. We evaluated the distribution of I(2) in meta-analyses of binary and continuous outcomes and explored hypotheses explaining the difference in distributions. After full-text screening, we selected 671 meta-analyses evaluating 557 binary and 352 continuous outcomes. Heterogeneity as assessed by I(2) proved higher in continuous than in binary outcomes: the proportion of continuous and binary outcomes reporting an I(2) of 0% was 34% vs. 52%, respectively, and reporting an I(2) of 60-100% was 39% vs. 14%. In continuous but not binary outcomes, I(2) increased with larger number of studies included in a meta-analysis. Increased precision and sample size do not explain the larger I(2) found in meta-analyses of continuous outcomes with a larger number of studies. Meta-analyses evaluating continuous outcomes showed substantially higher I(2) than meta-analyses of binary outcomes. Results suggest differing standards for interpreting I(2) in continuous vs. binary outcomes may be appropriate. Copyright © 2016 Elsevier Inc. All rights reserved.

[An evaluation of a continuing medical education program for primary care services in the prescription of hypoglycemic agents in diabetes mellitus type 2].

PubMed

Castro-Ríos, Angélica; Reyes-Morales, Hortensia; Pérez-Cuevas, Ricardo

2008-01-01

To evaluate the impact of a continuing medical education program on family doctors to improve prescription of hypoglycemic drugs. An observational study was conducted with two groups of comparison (with-without program) and before-after periods. The unit of analysis was the visit. The period of evaluation comprised six months before and six after implementing the program. The outcome variable was the appropriateness of prescription that was based upon two criteria: appropriate selection and proper indication of the drug. Logistic regression models and the double differences technique were used to analyze the information. Models were adjusted by independent variables related with the patient, the visit and the PCC, the more relevant ones were: sex, obesity, conditions other than diabetes, number of visits in the analyzed period, number of drugs prescribed, size of the PCC and period. the program increases 0.6% the probability of appropriate prescription and 11% the probability of appropriate choice of the hypoglycemic drug in obese patients.

Multiple imputation in the presence of non-normal data.

PubMed

Lee, Katherine J; Carlin, John B

2017-02-20

Multiple imputation (MI) is becoming increasingly popular for handling missing data. Standard approaches for MI assume normality for continuous variables (conditionally on the other variables in the imputation model). However, it is unclear how to impute non-normally distributed continuous variables. Using simulation and a case study, we compared various transformations applied prior to imputation, including a novel non-parametric transformation, to imputation on the raw scale and using predictive mean matching (PMM) when imputing non-normal data. We generated data from a range of non-normal distributions, and set 50% to missing completely at random or missing at random. We then imputed missing values on the raw scale, following a zero-skewness log, Box-Cox or non-parametric transformation and using PMM with both type 1 and 2 matching. We compared inferences regarding the marginal mean of the incomplete variable and the association with a fully observed outcome. We also compared results from these approaches in the analysis of depression and anxiety symptoms in parents of very preterm compared with term-born infants. The results provide novel empirical evidence that the decision regarding how to impute a non-normal variable should be based on the nature of the relationship between the variables of interest. If the relationship is linear in the untransformed scale, transformation can introduce bias irrespective of the transformation used. However, if the relationship is non-linear, it may be important to transform the variable to accurately capture this relationship. A useful alternative is to impute the variable using PMM with type 1 matching. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Climate Change and Human Health Impacts in the United States: An Update on the Results of the U.S. National Assessment

PubMed Central

Ebi, Kristie L.; Mills, David M.; Smith, Joel B.; Grambsch, Anne

2006-01-01

The health sector component of the first U.S. National Assessment, published in 2000, synthesized the anticipated health impacts of climate variability and change for five categories of health outcomes: impacts attributable to temperature, extreme weather events (e.g., storms and floods), air pollution, water- and food-borne diseases, and vector- and rodent-borne diseases. The Health Sector Assessment (HSA) concluded that climate variability and change are likely to increase morbidity and mortality risks for several climate-sensitive health outcomes, with the net impact uncertain. The objective of this study was to update the first HSA based on recent publications that address the potential impacts of climate variability and change in the United States for the five health outcome categories. The literature published since the first HSA supports the initial conclusions, with new data refining quantitative exposure–response relationships for several health end points, particularly for extreme heat events and air pollution. The United States continues to have a very high capacity to plan for and respond to climate change, although relatively little progress has been noted in the literature on implementing adaptive strategies and measures. Large knowledge gaps remain, resulting in a substantial need for additional research to improve our understanding of how weather and climate, both directly and indirectly, can influence human health. Filling these knowledge gaps will help better define the potential health impacts of climate change and identify specific public health adaptations to increase resilience. PMID:16966082

Can adverse maternal and perinatal outcomes be predicted when blood pressure becomes elevated? Secondary analyses from the CHIPS (Control of Hypertension In Pregnancy Study) randomized controlled trial.

PubMed

Magee, Laura A; von Dadelszen, Peter; Singer, Joel; Lee, Terry; Rey, Evelyne; Ross, Susan; Asztalos, Elizabeth; Murphy, Kellie E; Menzies, Jennifer; Sanchez, Johanna; Gafni, Amiram; Gruslin, Andrée; Helewa, Michael; Hutton, Eileen; Lee, Shoo K; Logan, Alexander G; Ganzevoort, Wessel; Welch, Ross; Thornton, Jim G; Moutquin, Jean Marie

2016-07-01

For women with chronic or gestational hypertension in CHIPS (Control of Hypertension In Pregnancy Study, NCT01192412), we aimed to examine whether clinical predictors collected at randomization could predict adverse outcomes. This was a planned, secondary analysis of data from the 987 women in the CHIPS Trial. Logistic regression was used to examine the impact of 19 candidate predictors on the probability of adverse perinatal (pregnancy loss or high level neonatal care for >48 h, or birthweight <10th percentile) or maternal outcomes (severe hypertension, preeclampsia, or delivery at <34 or <37 weeks). A model containing all candidate predictors was used to start the stepwise regression process based on goodness of fit as measured by the Akaike information criterion. For face validity, these variables were forced into the model: treatment group ("less tight" or "tight" control), antihypertensive type at randomization, and blood pressure within 1 week before randomization. Continuous variables were represented continuously or dichotomized based on the smaller p-value in univariate analyses. An area-under-the-receiver-operating-curve (AUC ROC) of ≥0.70 was taken to reflect a potentially useful model. Point estimates for AUC ROC were <0.70 for all but severe hypertension (0.70, 95% CI 0.67-0.74) and delivery at <34 weeks (0.71, 95% CI 0.66-0.75). Therefore, no model warranted further assessment of performance. CHIPS data suggest that when women with chronic hypertension develop an elevated blood pressure in pregnancy, or formerly normotensive women develop new gestational hypertension, maternal and current pregnancy clinical characteristics cannot predict adverse outcomes in the index pregnancy. © 2016 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

Patient satisfaction with psychotropic drugs: sensitivity to change and relationship to clinical status, quality-of-life, compliance and effectiveness of treatment. Results from a nation-wide 6-month prospective study.

PubMed

Gasquet, Isabelle; Tcherny-Lessenot, Stéphanie; Lépine, Jean-Pierre; Falissard, Bruno

2006-12-01

To see if patient satisfaction with psychotropics (PSP) could be used as a patient-oriented outcome variable in the evaluation of PSP drugs in clinical epidemiological studies, relationships between PSP, clinical status, QoL, compliance and the type of antipsychotic were analyzed. Elements of validation of PSP were also assessed. In a 6-month prospective study, 933 schizophrenic outpatients with initiation or change to their antipsychotic treatment were enrolled. Psychiatrists completed five CGI-SCH scales (positive, negative, cognitive, depressive and global), hospitalization, compliance, and prescription variables. Patients completed PSP, EuroQoL scales, sexual function and compliance variables. A satisfactory structural equation model was obtained showing significant relationships PSP/compliance (coef.=0.16), QoL/PSP (coef.=0.37), clinical status/QoL (coef.=0.61), clinical status/compliance (coef.=0.09). Patients receiving olanzapine were more satisfied than patients receiving other atypicals (coef.=012) and had better clinical status than patients treated with typicals (coef.=0.08). Evolution of PSP was related to clinical status, QoL, and continuation of treatment (all P<001). Sensitivity to change of PSP was moderate (effect size=0.2). PSP produced consistent results in relation to validated outcome variables. However, a single-item measure was not sufficiently sensitive to change. Multi-item questionnaires evaluating different dimensions are needed.

Provider continuity in family medicine: does it make a difference for total health care costs?

PubMed

De Maeseneer, Jan M; De Prins, Lutgarde; Gosset, Christiane; Heyerick, Jozef

2003-01-01

International comparisons of health care systems have shown a relationship at the macro level between a well-structured primary health care plan and lower total health care costs. The objective of this study was to assess whether provider continuity with a family physician is related to lower health care costs using the individual patient as the unit of analysis. We undertook a study of a stratified sample of patients (age, sex, region, insurance company) for which 2 cohorts were constructed based on the patients' utilization pattern of family medicine (provider continuity or not). Patient utilization patterns were observed for 2 years. The setting was the Belgian health care system. The participants were 4,134 members of the 2 largest health insurance companies in 2 regions (Aalst and Liège). The main outcome measures were the total health care costs of patients with and without provider continuity with a family physician, controlling for variables known to influence health care utilization (need factors, predisposing factors, enabling factors). Bivariate analyses showed that patients who were visiting the same family physician had a lower total cost for medical care. A multivariate linear regression showed that provider continuity with a family physician was one of the most important explanatory variables related to the total health care cost. Provider continuity with a family physician is related to lower total health care costs. This finding brings evidence to the debate on the importance of structured primary health care (with high continuity for family practice) for a cost-effective health policy.

Resident Participation in Fixation of Intertrochanteric Hip Fractures: Analysis of the NSQIP Database.

PubMed

Neuwirth, Alexander L; Stitzlein, Russell N; Neuwirth, Madalyn G; Kelz, Rachel K; Mehta, Samir

2018-01-17

Future generations of orthopaedic surgeons must continue to be trained in the surgical management of hip fractures. This study assesses the effect of resident participation on outcomes for the treatment of intertrochanteric hip fractures. The National Surgical Quality Improvement Program (NSQIP) database (2010 to 2013) was queried for intertrochanteric hip fractures (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] code 820.21) treated with either extramedullary (Current Procedural Terminology [CPT] code 27244) or intramedullary (CPT code 27245) fixation. Demographic variables, including resident participation, as well as primary (death and serious morbidity) and secondary outcome variables were extracted for analysis. Univariate, propensity score-matched, and multivariate logistic regression analyses were performed to evaluate outcome variables. Data on resident participation were available for 1,764 cases (21.0%). Univariate analyses for all intertrochanteric hip fractures demonstrated no significant difference in 30-day mortality (6.3% versus 7.8%; p = 0.264) or serious morbidity (44.9% versus 43.2%; p = 0.506) between the groups with and without resident participation. Multivariate and propensity score-matched analyses gave similar results. Resident involvement was associated with prolonged operating-room time, length of stay, and time to discharge when a prolonged case was defined as one above the 90th percentile for time parameters. Resident participation was not associated with an increase in morbidity or mortality but was associated with an increase in time-related secondary outcome measures. While attending surgeon supervision is necessary, residents can and should be involved in the care of these patients without concern that resident involvement negatively impacts perioperative morbidity and mortality. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clinical and demographic features of burn injuries in karachi: a six-year experience at the burns centre, civil hospital, Karachi

PubMed Central

Ali, S.A.; Hamiz-ul-Fawwad, S.; Al-Ibran, E.; Ahmed, G.; Saleem, A.; Mustafa, D.; Hussain, M.

2016-01-01

Summary Burn injuries are a leading cause of morbidity and mortality, with 195,000 deaths annually. This study was conducted to identify the demographics of burn victims and the effect of different variables on the outcome of their injuries. 4016 patients admitted to the Burns Centre, Civil Hospital Karachi from January 2006 to December 2011 were retrospectively analyzed. Demographics, burn injury details and their outcome were recorded in a pre-designed questionnaire. Injuries were categorized as: fire, chemical, scald or electrical. To estimate total body surface area (TBSA) burned in adults, the rule of nines was used. For children and infants, the Lund-Browder chart was employed. SPSS v16.0 software was used for analysis. Frequencies and percentages of all variables, and the measure of central tendencies and dispersion for continuous variables were calculated. Cross tabs were used to assess mortality. Mean age was 28.13 years. More than half of the cases (n=2337, 58.2%) were aged between 16-30 years. Labourers, housewives and students were the most commonly affected groups. Burn injuries by flame/fire and electricity were most common. Most cases were accidental, followed by suicide attempts and homicides. Mean percentage of TBSA affected was 35.49%. Mean duration of hospital stay was 16.45 days. 50.6% of the expired cases were females. The mean age of expired patients was 30.07 while for patients who survived it was 27.01 years. The outcome of burn injuries is related to various demographic factors. Female gender, increasing age, burn injuries following suicide attempts and greater surface area involvement predict poor outcome. PMID:27857643

[Definition of low threshold volumes for quality assurance: conceptual and methodological issues involved in the definition and evaluation of thresholds for volume outcome relations in clinical care].

PubMed

Wetzel, Hermann

2006-01-01

In a large number of mostly retrospective association studies, a statistical relationship between volume and quality of health care has been reported. However, the relevance of these results is frequently limited by methodological shortcomings. In this article, criteria for the evidence and definition of thresholds for volume-outcome relations are proposed, e.g. the specification of relevant outcomes for quality indicators, analysis of volume as a continuous variable with an adequate case-mix and risk adjustment, accounting for cluster effects and considering mathematical models for the derivation of cut-off values. Moreover, volume thresholds are regarded as surrogate parameters for the indirect classification of the quality of care, whose diagnostic validity and effectiveness in improving health care quality need to be evaluated in prospective studies.

The Recipient Venule in Supermicrosurgical Lymphaticovenular Anastomosis: Flow Dynamic Classification and Correlation with Surgical Outcomes.

PubMed

Visconti, Giuseppe; Salgarello, Marzia; Hayashi, Akitatsu

2018-05-12

 Venules have been usually neglected in the literature on lymphaticovenular anastomosis (LVA). The aim of this study was to analyze the flow dynamic of recipient venules in LVA and their impact on the surgical outcomes.  Data from 128 patients affected by extremity lymphedema, who underwent LVA, were collected in two institutions from August 2014 to May 2016. Recipient venules were classified according to their flow dynamic into backflow, slack, and outlet (BSO classification). Quantitative (lower extremity lymphedema/upper extremity lymphedema index) and qualitative outcomes (needing of compression garment and compression garment class) were evaluated. Chi-square test or Fisher's exact test was used for categorical variables and independent-samples t -test for continuous variables. The association between lymphatic collector degeneration status (normal, ectasis, contractile, sclerotic type [NECST]) and BSO classification with the outcomes was analyzed by the Mantel-Haenszel test.  On a total of 128 patients, 37 suffered from upper and 91 from lower limb lymphedema. An average number of four LVA were performed for each patient (range: 2-8). A significant association was observed between NECST and BSO categories and the outcomes were evaluated. Patients with contractile and sclerotic collectors had 2.24 times the odd of having poor composite outcome compared with those with normal-to-ectasis collectors ( p  < 0.05). Patients with backflow venules had 3.32 times the odd of having poor composite outcome compared with those without outlet or slack pattern ( p  < 0.05).  The subtype of recipient venule flow dynamic has a significant impact on the surgical outcome of patients undergoing LVA for the treatment of lymphedema, regardless of the lymphatic collector degeneration status. Locating favorable venules in the preoperative mapping might enhance the surgical outcomes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Parents’ Marital Distress, Divorce, and Remarriage: Links with Daughters’ Early Family Formation Transitions

PubMed Central

Amato, Paul R.; Kane, Jennifer B.

2011-01-01

We used data from the Add Health study to estimate the effects of parents’ marital status and relationship distress on daughters’ early family formation transitions. Outcomes included traditional transitions (marriage and marital births) and nontraditional transitions (cohabitation and nonmarital births). Relationship distress among continuously married parents was not related to any outcome. Offspring with single parents and remarried parents had an elevated risk of nonmarital births and nonmarital cohabitation. Offspring with remarried parents with a high-distress relationship had an elevated risk of early marriages and marital births. These results, combined with analyses of mediating variables, provide the strongest support for a modeling perspective, although some support also was found for a perspective based on escape from stress. PMID:21785523

AiRCare: A naturalistic evaluation of the effectiveness of a protracted telephone-based recovery assistance program on continuing care outcomes.

PubMed

Proctor, Steven L; Wainwright, Jaclyn L; Herschman, Philip L; Kopak, Albert M

2017-02-01

Substance use disorder treatments are increasingly being contextualized within a disease management framework. Within this context, there is an identified need to maintain patients in treatment for longer periods of time in order to help them learn how to manage their disease. One way to meet this need is through telephone-based interventions that engage patients, and include more active outreach attempts and involvement of the patient's family. This study sought to evaluate the effectiveness of three formats of an intensive 12-month post-discharge telephone-based case management approach (AiRCare) on adherence to continuing care plans and substance use outcomes. Data were abstracted from electronic medical records for 379 patients (59.9% male) discharged from a residential treatment program located in the southwestern U.S. from 2013 to 2015. Patients were categorized into one of three groups and received telephone contacts based on their self-selection upon admission to residential treatment (i.e., patient only, family only, and both patient and family). Outcome variables included re-engagement and re-admission rates, quality of life, abstinence rates at 6 and 12 months, and compliance with continuing care plans. Favorable short- and long-term outcomes were found for the majority of patients, irrespective of case management group. There appeared to be some value in the addition of family contacts to patient contacts with respect to reducing risk for 12-month re-admission to residential care. These positive but preliminary indications of the effectiveness of AiRCare require replication in a well-powered, randomized controlled trial. Copyright © 2016 Elsevier Inc. All rights reserved.

Practice and transfer of the frequency structures of continuous isometric force.

PubMed

King, Adam C; Newell, Karl M

2014-04-01

The present study examined the learning, retention and transfer of task outcome and the frequency-dependent properties of isometric force output dynamics. During practice participants produced isometric force to a moderately irregular target pattern either under a constant or variable presentation. Immediate and delayed retention tests examined the persistence of practice-induced changes of force output dynamics and transfer tests investigated performance to novel (low and high) irregular target patterns. The results showed that both constant and variable practice conditions exhibited similar reductions in task error but that the frequency-dependent properties were differentially modified across the entire bandwidth (0-12Hz) of force output dynamics as a function of practice. Task outcome exhibited persistent properties on the delayed retention test whereas the retention of faster time scales processes (i.e., 4-12Hz) of force output was mediated as a function of frequency structure. The structure of the force frequency components during early practice and following a rest interval was characterized by an enhanced emphasis on the slow time scales related to perceptual-motor feedback. The findings support the proposition that there are different time scales of learning at the levels of task outcome and the adaptive frequency bandwidths of force output dynamics. Copyright © 2014 Elsevier B.V. All rights reserved.

Coordinating the effects of multiple variables: a skill fundamental to scientific thinking.

PubMed

Kuhn, Deanna; Pease, Maria; Wirkala, Clarice

2009-07-01

The skill of predicting outcomes based on simultaneous effects of multiple factors was examined. Over five sessions, 91 sixth graders engaged this task either individually or in pairs and either preceded or followed by six sessions on the more widely studied inquiry task that requires designing and interpreting experiments to identify individual effects. Final assessment, while indicating a high level of mastery on the inquiry task, showed progress but continuing conceptual challenges on the multivariable prediction task having to do with understanding of variables, variable levels, and consistency of a variable's operation across occasions. Task order had a significant but limited effect, and social collaboration conferred only a temporary benefit that disappeared in a final individual assessment. In a follow-up study, the lack of effect of social collaboration was confirmed, as was that of feedback on incorrect answers. Although fundamental to science, the concept that variables operate jointly and, under equivalent conditions, consistently across occasions is one that children appear to acquire only gradually and, therefore, one that cannot be assumed to be in place.

A comparison of pregnancy outcomes in Ghanaian women with varying dietary diversity: a prospective cohort study protocol

PubMed Central

Saaka, Mahama; Siassi, Fereydoun; Qorbani, Mostafa; Yavari, Parvaneh; Danquah, Ina; Sotoudeh, Gity

2016-01-01

Introduction Poor dietary intake during pregnancy can have negative repercussions on the mother and fetus. This study therefore aims to explore the dietary diversity (DD) of pregnant women and its associations with pregnancy outcomes among women in Northern Ghana. The main outcome variables to be measured are gestational weight gain and birth weight. Methods and analysis A prospective cohort study design will be used and 600 pregnant women in their first trimester will be systematically recruited at health facilities and followed until delivery. In three follow-up visits after recruitment, information on sociodemographic and general characteristics, physical activity (International Physical Activity Questionnaire (IPAQ) short form, dietary intake (24-hour food recall), anthropometry and pregnancy outcomes will be collected. DD will be measured three times using the minimum DD-women (MDD-W) indicator and the mean of the three values overall will be used to determine low (<5 food groups) and high (≥5 food groups) DD. Data will be analysed using SPSS. Comparisons between groups (categorical data) will be made using the χ2 test for proportions, and t-tests and ANOVA will be performed on continuous variables. Regression analysis will be used to identify independent outcome predictors while controlling for possible confounding factors. The results may help to identify differences in DD between healthy and unhealthy pregnancy outcomes. Ethics and dissemination The study protocol has been approved by the ethics committee of Tehran University of Medical Sciences and the ethical review committee of the Tamale Teaching Hospital. Written informed consent will be obtained from all subjects. The results will be published in due course. PMID:27655259

CLINICAL APPLICATIONS OF CRYOTHERAPY AMONG SPORTS PHYSICAL THERAPISTS.

PubMed

Hawkins, Shawn W; Hawkins, Jeremy R

2016-02-01

Therapeutic modalities (TM) are used by sports physical therapists (SPT) but how they are used is unknown. To identify the current clinical use patterns for cryotherapy among SPT. Cross-sectional survey. All members (7283) of the Sports Physical Therapy Section of the APTA were recruited. A scenario-based survey using pre-participation management of an acute or sub-acute ankle sprain was developed. A Select Survey link was distributed via email to participants. Respondents selected a treatment approach based upon options provided. Follow-up questions were asked. The survey was available for two weeks with a follow-up email sent after one week. Question answers were the main outcome measures. Reliability: Cronbach's alpha=>0.9. The SPT response rate = 6.9% (503); responses came from 48 states. Survey results indicated great variability in respondents' approaches to the treatment of an acute and sub-acute ankle sprain. SPT applied cryotherapy with great variability and not always in accordance to the limited research on the TM. Continuing education, application of current research, and additional outcomes based research needs to remain a focus for clinicians. 3.

Gaussification and entanglement distillation of continuous-variable systems: a unifying picture.

PubMed

Campbell, Earl T; Eisert, Jens

2012-01-13

Distillation of entanglement using only Gaussian operations is an important primitive in quantum communication, quantum repeater architectures, and distributed quantum computing. Existing distillation protocols for continuous degrees of freedom are only known to converge to a Gaussian state when measurements yield precisely the vacuum outcome. In sharp contrast, non-Gaussian states can be deterministically converted into Gaussian states while preserving their second moments, albeit by usually reducing their degree of entanglement. In this work-based on a novel instance of a noncommutative central limit theorem-we introduce a picture general enough to encompass the known protocols leading to Gaussian states, and new classes of protocols including multipartite distillation. This gives the experimental option of balancing the merits of success probability against entanglement produced.

ADRB2 and LEPR gene polymorphisms: synergistic effects on the risk of obesity in Japanese.

PubMed

Pereira, Tiago V; Mingroni-Netto, Regina C; Yamada, Yoshiji

2011-07-01

The objective of the present study was to validate a recently reported synergistic effect between variants located in the leptin receptor (LEPR) gene and in the β-2 adrenergic receptor (ADRB2) gene on the risk of overweight/obesity. We studied a middle-aged/elderly sample of 4,193 nondiabetic Japanese subjects stratified according gender (1,911 women and 2,282 men). The LEPR Gln223Arg (rs1137101) variant as well as both ADRB2 Arg16Gly (rs1042713) and Gln27Glu (rs1042714) polymorphisms were analyzed. The primary outcome was the risk of overweight/obesity defined as BMI ≥25 kg/m(2), whereas secondary outcomes included the risk of a BMI ≥27 kg/m(2) and BMI as a continuous variable. None of the studied polymorphisms showed statistically significant individual effects, regardless of the group or phenotype studied. Haplotype analysis also did not disclose any associations of ADRB2 polymorphisms with BMI. However, dimensionality reduction-based models confirmed significant interactions among the investigated variants for BMI as a continuous variable as well as for the risk of obesity defined as BMI ≥27 kg/m(2). All disclosed interactions were found in men only. Our results provide external validation for a male specific ADRB2-LEPR interaction effect on the risk of overweight/obesity, but indicate that effect sizes associated with these interactions may be smaller in the population studied.

Virtual Learning Environment in Continuing Education for Nursing in Oncology: an Experimental Study.

PubMed

das Graças Silva Matsubara, Maria; De Domenico, Edvane Birelo Lopes

2016-12-01

Nurses working in oncology require continuing education and nowadays distance education is a possibility. To compare learning outcomes of the professionals participating in classroom learning versus distance learning; describing the sociodemographic characteristics and digital fluency of participants; comparing learning outcomes with independent variables; assessing the adequacy of educational practices in Virtual Environment Moodle Learning through the constructivist online learning environment survey. An experimental, randomized controlled study; conducted at the A C Camargo Cancer Center, located in São Paulo, SP, Brazil. The study included 97 nurses, with average training of 1 to 2 years. A control group (n = 44) had face to face training and the experiment group (n = 53) had training by distance learning, both with identical program content. The dependent variable was the result of learning, measured by applying a pre-assessment questionnaire and post-intervention for both groups. The sociodemographic and digital fluency data were uniform among the groups. The performance of both groups was statistically significant (p 0.005), and the control group had a greater advantage (40.4 %). Distance education has proven to be an effective alternative for training nurses, especially when they have more complex knowledge, more experience in the area and institutional time. Distance Education may be a possibility for the training of nurses for work in oncology. The association of age, training time and the institution, and the experience in Oncology interfered in the performance of both groups.

A prospective 2-year examination of cognitive and behavioral correlates of provoked vestibulodynia outcomes.

PubMed

Davis, Seth N P; Bergeron, Sophie; Bois, Katy; Sadikaj, Gentiana; Binik, Yitzchak M; Steben, Marc

2015-04-01

Provoked vestibulodynia (PVD) is a common genital pain disorder in women that is associated with sexual dysfunction and lowered sexual satisfaction. A potentially applicable cognitive-behavioral model of chronic pain and disability is the fear-avoidance model (FAM) of pain. The FAM posits that cognitive variables, such as pain catastrophizing, fear, and anxiety lead to avoidance of pain-provoking behaviors (eg, intercourse), resulting in continued pain and disability. Although some of the FAM variables have been shown to be associated with PVD pain and sexuality outcomes, the model as a whole has never been tested in this population. An additional protective factor, pain self-efficacy (SE), is also associated with PVD, but has not been tested within the FAM model. Using a 2-year longitudinal design, we examine (1) whether initial levels (T1) of the independent FAM variables and pain SE were associated with changes in pain, sexual function, and sexual satisfaction over the 2-year time period; (2) the prospective contribution of changes in cognitive-affective (FAM) variables to changes in pain, and sexuality outcomes; and (3) whether these were mediated by behavioral change (avoidance of intercourse). A sample of 222 women with PVD completed self-report measures of FAM variables, SE, pain, sexual function, and sexual satisfaction at time 1 and at a 2-year follow-up. Structural equation modeling with Latent Difference Scores was used to examine changes and to examine mediation between variables. Questionnaires included the Pain Catastrophizing Scale, McGill Pain Questionnaire, Trait Anxiety Inventory, Pain Self-Efficacy Scale, and Global Measure of Sexual Satisfaction, Female Sexual Function Index. Participants who reported higher SE at T1 reported greater declines in pain, greater increases in sexual satisfaction, and greater declines in sexual function over the 2 time points. The overall change model did not support the FAM using negative cognitive-affective variables. Only increases in pain SE were associated with reductions in pain intensity. The relationship between changes in SE and changes in pain was partially mediated through changes in avoidance (more intercourse attempts). The same pattern of results was found for changes in sexual satisfaction as the outcome, and a partial mediation effect was found. There were no significant predictors of changes in sexual function other than T1 SE. Changes in both cognitive and behavioral variables were significantly associated with improved pain and sexual satisfaction outcomes. However, it was the positive changes in SE that better predicted changes in avoidance behavior, pain, and sexual satisfaction. Cognitive-behavior therapy is often focused on changing negative pain-related cognitions to reduce avoidance and pain, but the present results demonstrate the potential importance of bolstering positive self-beliefs as well. Indeed, before engaging in exposure therapies, SE beliefs should be assessed and potentially targeted to improve adherence to exposure strategies.

Risk factors and outcomes of high peritonitis rate in continuous ambulatory peritoneal dialysis patients: A retrospective study.

PubMed

Tian, Yuanshi; Xie, Xishao; Xiang, Shilong; Yang, Xin; Zhang, Xiaohui; Shou, Zhangfei; Chen, Jianghua

2016-12-01

Peritonitis remains a major complication of peritoneal dialysis (PD). A high peritonitis rate (HPR) affects continuous ambulatory peritoneal dialysis (CAPD) patients' technique survival and mortality. Predictors and outcomes of HPR, rather than the first peritonitis episode, were rarely studied in the Chinese population. In this study, we examined the risk factors associated with HPR and its effects on clinical outcomes in CAPD patients.This is a single center, retrospective, observational cohort study. A total of 294 patients who developing at least 1 episode of peritonitis were followed up from March 1st, 2002, to July 31, 2014, in our PD center. Multivariate logistic regression was used to determine the factors associated with HPR, and the Cox proportional hazard model was conducted to assess the effects of HPR on clinical outcomes.During the study period of 2917.5 patient-years, 489 episodes of peritonitis were recorded, and the total peritonitis rate was 0.168 episodes per patient-year. The multivariate analysis showed that factors associated with HPR include a quick occurrence of peritonitis after CAPD initiation (shorter than 12 months), and a low serum albumin level at the start of CAPD. In the Cox proportional hazard model, HPR was a significant predictor of technique failure. There were no differences between HPR and low peritonitis rate (LPR) group for all-cause mortality. However, when the peritonitis rate was considered as a continuous variable, a positive correlation was observed between the peritonitis rate and mortality.We found the quick peritonitis occurrence after CAPD and the low serum albumin level before CAPD were strongly associated with an HPR. Also, our results verified that HPR was positively correlated with technique failure. More importantly, the increase in the peritonitis rate suggested a higher risk of all-cause mortality.These results may help to identify and target patients who are at higher risk of HPR at the start of CAPD and to take interventions to reduce peritonitis incidence and improve clinical outcomes.

Risk factors and outcomes of high peritonitis rate in continuous ambulatory peritoneal dialysis patients

PubMed Central

Tian, Yuanshi; Xie, Xishao; Xiang, Shilong; Yang, Xin; Zhang, Xiaohui; Shou, Zhangfei; Chen, Jianghua

2016-01-01

Abstract Peritonitis remains a major complication of peritoneal dialysis (PD). A high peritonitis rate (HPR) affects continuous ambulatory peritoneal dialysis (CAPD) patients’ technique survival and mortality. Predictors and outcomes of HPR, rather than the first peritonitis episode, were rarely studied in the Chinese population. In this study, we examined the risk factors associated with HPR and its effects on clinical outcomes in CAPD patients. This is a single center, retrospective, observational cohort study. A total of 294 patients who developing at least 1 episode of peritonitis were followed up from March 1st, 2002, to July 31, 2014, in our PD center. Multivariate logistic regression was used to determine the factors associated with HPR, and the Cox proportional hazard model was conducted to assess the effects of HPR on clinical outcomes. During the study period of 2917.5 patient-years, 489 episodes of peritonitis were recorded, and the total peritonitis rate was 0.168 episodes per patient-year. The multivariate analysis showed that factors associated with HPR include a quick occurrence of peritonitis after CAPD initiation (shorter than 12 months), and a low serum albumin level at the start of CAPD. In the Cox proportional hazard model, HPR was a significant predictor of technique failure. There were no differences between HPR and low peritonitis rate (LPR) group for all-cause mortality. However, when the peritonitis rate was considered as a continuous variable, a positive correlation was observed between the peritonitis rate and mortality. We found the quick peritonitis occurrence after CAPD and the low serum albumin level before CAPD were strongly associated with an HPR. Also, our results verified that HPR was positively correlated with technique failure. More importantly, the increase in the peritonitis rate suggested a higher risk of all-cause mortality. These results may help to identify and target patients who are at higher risk of HPR at the start of CAPD and to take interventions to reduce peritonitis incidence and improve clinical outcomes. PMID:27930566

Outcomes of laparoscopic resection of Meckel's diverticulum are equivalent to open laparotomy.

PubMed

Ezekian, Brian; Leraas, Harold J; Englum, Brian R; Gilmore, Brian F; Reed, Christopher; Fitzgerald, Tamara N; Rice, Henry E; Tracy, Elisabeth T

2018-03-15

Meckel's diverticulum (MD) is a common congenital anomaly caused by failure of involution of the omphalomesenteric duct. Enthusiasm for minimally invasive surgery (MIS) in children has burgeoned as technologies have advanced, but the outcomes of laparoscopic resection in comparison to open laparotomy for MD remain poorly defined. We queried a large national database to compare current practice patterns and clinical outcomes between surgical approaches for MD in the pediatric population. The National Surgical Quality Improvement Program-Pediatric (NSQIP-Ped) database was queried for patients undergoing surgical intervention for MD (2011-2014). Patients were stratified by surgical approach. Baseline characteristics, intraoperative variables, and perioperative complications were compared by univariate analysis using Pearson's χ 2 test for categorical variables and Kruskall-Wallis test for continuous variables. Primary outcomes of interest were length of stay (LOS), rate of readmission, and 30-day mortality. Secondary outcomes included operative time, anesthesia time, postoperative complications, and rates of reoperation. A total of 148 cases of MD were identified, of which 73 (49.3%) were initially managed with a laparoscopic approach and 75 (50.7%) were managed with an open approach. We found a high rate of conversion from laparoscopy to an open approach (20/73 or 27.4%). The median age of the laparoscopic group was higher than the open group (8.3 vs. 2.5years, p<0.001). Operative and anesthesia time, LOS, 30-day mortality, post-operative complications, and rates of reoperation and readmission were similar between groups (all p>0.05). Nearly half of all resections for MD in children are now approached laparoscopically. This approach has equivalent outcomes to traditional open laparotomy. More widespread use of a hybrid approach with laparoscopy and exteriorization of the small bowel through an extended port site may facilitate avoiding open laparotomy. Routine conversion to open for palpation of the MD or segmental small bowel resection should be avoided in the absence of compelling intra-operative findings or operative complications. Level III (retrospective comparative study). Copyright © 2018 Elsevier Inc. All rights reserved.

Use of continuous glucose monitoring as an outcome measure in clinical trials.

PubMed

Beck, Roy W; Calhoun, Peter; Kollman, Craig

2012-10-01

Although developed to be a management tool for individuals with diabetes, continuous glucose monitoring (CGM) also has potential value for the assessment of outcomes in clinical studies. We evaluated using CGM as such an outcome measure. Data were analyzed from six previously completed inpatient studies in which both CGM (Freestyle Navigator™ [Abbott Diabetes Care, Alameda, CA] or Guardian(®) [Medtronic, Northridge, CA]) and reference glucose measurements were available. The analyses included 97 days of data from 93 participants with type 1 diabetes (age range, 5-57 years; mean, 18 ± 12 years). Mean glucose levels per day were similar for the CGM and reference measurements (median, 148 mg/dL vs. 143 mg/dL, respectively; P = 0.92), and the correlation of the two was high (r = 0.89). Similarly, most glycemia metrics showed no significant differences comparing CGM and reference values, except that the nadir glucose tended to be slightly lower and peak glucose slightly higher with reference measurements than CGM measurements (respective median, 59 mg/dL vs. 66 mg/dL [P = 0.05] and 262 mg/dL vs. 257 mg/dL [P = 0.003]) and glucose variability as measured with the coefficient of variation was slightly lower with CGM than reference measurements (respective median, 31% vs. 35%; P<0.001). A reasonably high degree of concordance exists when comparing outcomes based on CGM measurements with outcomes based on reference blood glucose measurements. CGM inaccuracy and underestimation of the extremes of hyperglycemia and hypoglycemia can be accounted for in a clinical trial's study design. Thus, in appropriate settings, CGM can be a very meaningful and feasible outcome measure for clinical trials.

Use of Continuous Glucose Monitoring as an Outcome Measure in Clinical Trials

PubMed Central

Calhoun, Peter; Kollman, Craig

2012-01-01

Abstract Objective Although developed to be a management tool for individuals with diabetes, continuous glucose monitoring (CGM) also has potential value for the assessment of outcomes in clinical studies. We evaluated using CGM as such an outcome measure. Research Design and Methods Data were analyzed from six previously completed inpatient studies in which both CGM (Freestyle Navigator™ [Abbott Diabetes Care, Alameda, CA] or Guardian® [Medtronic, Northridge, CA]) and reference glucose measurements were available. The analyses included 97 days of data from 93 participants with type 1 diabetes (age range, 5–57 years; mean, 18±12 years). Results Mean glucose levels per day were similar for the CGM and reference measurements (median, 148 mg/dL vs. 143 mg/dL, respectively; P=0.92), and the correlation of the two was high (r=0.89). Similarly, most glycemia metrics showed no significant differences comparing CGM and reference values, except that the nadir glucose tended to be slightly lower and peak glucose slightly higher with reference measurements than CGM measurements (respective median, 59 mg/dL vs. 66 mg/dL [P=0.05] and 262 mg/dL vs. 257 mg/dL [P=0.003]) and glucose variability as measured with the coefficient of variation was slightly lower with CGM than reference measurements (respective median, 31% vs. 35%; P<0.001). Conclusions A reasonably high degree of concordance exists when comparing outcomes based on CGM measurements with outcomes based on reference blood glucose measurements. CGM inaccuracy and underestimation of the extremes of hyperglycemia and hypoglycemia can be accounted for in a clinical trial's study design. Thus, in appropriate settings, CGM can be a very meaningful and feasible outcome measure for clinical trials. PMID:23013201

Temperature variability during targeted temperature management is not associated with neurological outcomes following cardiac arrest.

PubMed

Nayeri, Arash; Bhatia, Nirmanmoh; Holmes, Benjamin; Borges, Nyal; Armstrong, William; Xu, Meng; Farber-Eger, Eric; Wells, Quinn S; McPherson, John A

2017-06-01

Recent studies on comatose survivors of cardiac arrest undergoing targeted temperature management (TTM) have shown similar outcomes at multiple target temperatures. However, details regarding core temperature variability during TTM and its prognostic implications remain largely unknown. We sought to assess the association between core temperature variability and neurological outcomes in patients undergoing TTM following cardiac arrest. We analyzed a prospectively collected cohort of 242 patients treated with TTM following cardiac arrest at a tertiary care hospital between 2007 and 2014. Core temperature variability was defined as the statistical variance (i.e. standard deviation squared) amongst all core temperature recordings during the maintenance phase of TTM. Poor neurological outcome at hospital discharge, defined as a Cerebral Performance Category (CPC) score>2, was the primary outcome. Death prior to hospital discharge was assessed as the secondary outcome. Multivariable logistic regression was used to examine the association between temperature variability and neurological outcome or death at hospital discharge. A poor neurological outcome was observed in 147 (61%) patients and 136 (56%) patients died prior to hospital discharge. In multivariable logistic regression, increased core temperature variability was not associated with increased odds of poor neurological outcomes (OR 0.38, 95% CI 0.11-1.38, p=0.142) or death (OR 0.43, 95% CI 0.12-1.53, p=0.193) at hospital discharge. In this study, individual core temperature variability during TTM was not associated with poor neurological outcomes or death at hospital discharge. Copyright © 2017 Elsevier Inc. All rights reserved.

Verification of relationships between anthropometric variables among ureteral stents recipients and ureteric lengths: a challenge for Vitruvian-da Vinci theory.

PubMed

Acelam, Philip A

2015-01-01

To determine and verify how anthropometric variables correlate to ureteric lengths and how well statistical models approximate the actual ureteric lengths. In this work, 129 charts of endourological patients (71 females and 58 males) were studied retrospectively. Data were gathered from various research centers from North and South America. Continuous data were studied using descriptive statistics. Anthropometric variables (age, body surface area, body weight, obesity, and stature) were utilized as predictors of ureteric lengths. Linear regressions and correlations were used for studying relationships between the predictors and the outcome variables (ureteric lengths); P-value was set at 0.05. To assess how well statistical models were capable of predicting the actual ureteric lengths, percentages (or ratios of matched to mismatched results) were employed. The results of the study show that anthropometric variables do not correlate well to ureteric lengths. Statistical models can partially estimate ureteric lengths. Out of the five anthropometric variables studied, three of them: body frame, stature, and weight, each with a P<0.0001, were significant. Two of the variables: age (R (2)=0.01; P=0.20) and obesity (R (2)=0.03; P=0.06), were found to be poor estimators of ureteric lengths. None of the predictors reached the expected (match:above:below) ratio of 1:0:0 to qualify as reliable predictors of ureteric lengths. There is not sufficient evidence to conclude that anthropometric variables can reliably predict ureteric lengths. These variables appear to lack adequate specificity as they failed to reach the expected (match:above:below) ratio of 1:0:0. Consequently, selections of ureteral stents continue to remain a challenge. However, height (R (2)=0.68) with the (match:above:below) ratio of 3:3:4 appears suited for use as estimator, but on the basis of decision rule. Additional research is recommended for stent improvements and ureteric length determinations.

Verification of relationships between anthropometric variables among ureteral stents recipients and ureteric lengths: a challenge for Vitruvian-da Vinci theory

PubMed Central

Acelam, Philip A

2015-01-01

Objective To determine and verify how anthropometric variables correlate to ureteric lengths and how well statistical models approximate the actual ureteric lengths. Materials and methods In this work, 129 charts of endourological patients (71 females and 58 males) were studied retrospectively. Data were gathered from various research centers from North and South America. Continuous data were studied using descriptive statistics. Anthropometric variables (age, body surface area, body weight, obesity, and stature) were utilized as predictors of ureteric lengths. Linear regressions and correlations were used for studying relationships between the predictors and the outcome variables (ureteric lengths); P-value was set at 0.05. To assess how well statistical models were capable of predicting the actual ureteric lengths, percentages (or ratios of matched to mismatched results) were employed. Results The results of the study show that anthropometric variables do not correlate well to ureteric lengths. Statistical models can partially estimate ureteric lengths. Out of the five anthropometric variables studied, three of them: body frame, stature, and weight, each with a P<0.0001, were significant. Two of the variables: age (R2=0.01; P=0.20) and obesity (R2=0.03; P=0.06), were found to be poor estimators of ureteric lengths. None of the predictors reached the expected (match:above:below) ratio of 1:0:0 to qualify as reliable predictors of ureteric lengths. Conclusion There is not sufficient evidence to conclude that anthropometric variables can reliably predict ureteric lengths. These variables appear to lack adequate specificity as they failed to reach the expected (match:above:below) ratio of 1:0:0. Consequently, selections of ureteral stents continue to remain a challenge. However, height (R2=0.68) with the (match:above:below) ratio of 3:3:4 appears suited for use as estimator, but on the basis of decision rule. Additional research is recommended for stent improvements and ureteric length determinations. PMID:26317082

Motivational deficits in major depressive disorder: Cross-sectional and longitudinal relationships with functional impairment and subjective well-being.

PubMed

Fervaha, Gagan; Foussias, George; Takeuchi, Hiroyoshi; Agid, Ofer; Remington, Gary

2016-04-01

Many individuals with major depressive disorder present with prominent motivational deficits; however, the effect of these symptoms on functional outcomes in the illness remains unclear. Individuals with major depression who participated in the Sequenced Treatment Alternatives to Relieve Depression study were included in the present investigation (N=1563). Motivational deficits were evaluated using a derived measure from the Hamilton Depression Rating Scale, while functioning was assessed using the Work and Social Adjustment Scale. Subjective outcomes were also evaluated using the Quality of Life Enjoyment and Satisfaction Questionnaire. After treatment with citalopram, over 70% of participants continued to experience some degree of motivational deficits. These deficits were significantly associated with greater functional impairments both globally and in each domain of functioning evaluated. These symptoms were also linked to worse subjective outcomes such as overall life satisfaction and quality of life. Change in the severity of motivational deficits over time was significantly linked with changes in outcome. Motivational deficits continued to demonstrate a significant association with outcomes, even after controlling for potentially confounding variables such as duration of depressive episode and severity of other depressive symptoms. Motivational deficits are significantly linked to the functional impairment present in many people with major depression, just as they are in other psychiatric illnesses such as schizophrenia. A greater understanding of the underlying mechanisms of these motivational deficits in particular, beyond other depressive symptoms, is critical to the development of strategies aimed at enhancing functional recovery and improved subjective well-being. Copyright © 2015 Elsevier Inc. All rights reserved.

Continuous glucose monitoring: A review of the technology and clinical use.

PubMed

Klonoff, David C; Ahn, David; Drincic, Andjela

2017-11-01

Continuous glucose monitoring (CGM) is an increasingly adopted technology for insulin-requiring patients that provides insights into glycemic fluctuations. CGM can assist patients in managing their diabetes with lifestyle and medication adjustments. This article provides an overview of the technical and clinical features of CGM based on a review of articles in PubMed on CGM from 1999 through January 31, 2017. A detailed description is presented of three professional (retrospective), three personal (real-time) continuous glucose monitors, and three sensor integrated pumps (consisting of a sensor and pump that communicate with each other to determine an optimal insulin dose and adjust the delivery of insulin) that are currently available in United States. We have reviewed outpatient CGM outcomes, focusing on hemoglobin A1c (A1C), hypoglycemia, and quality of life. Issues affecting accuracy, detection of glycemic variability, strategies for optimal use, as well as cybersecurity and future directions for sensor design and use are discussed. In conclusion, CGM is an important tool for monitoring diabetes that has been shown to improve outcomes in patients with type 1 diabetes mellitus. Given currently available data and technological developments, we believe that with appropriate patient education, CGM can also be considered for other patient populations. Copyright © 2017 Elsevier B.V. All rights reserved.

A systematic review of statistical methods used to test for reliability of medical instruments measuring continuous variables.

PubMed

Zaki, Rafdzah; Bulgiba, Awang; Nordin, Noorhaire; Azina Ismail, Noor

2013-06-01

Reliability measures precision or the extent to which test results can be replicated. This is the first ever systematic review to identify statistical methods used to measure reliability of equipment measuring continuous variables. This studyalso aims to highlight the inappropriate statistical method used in the reliability analysis and its implication in the medical practice. In 2010, five electronic databases were searched between 2007 and 2009 to look for reliability studies. A total of 5,795 titles were initially identified. Only 282 titles were potentially related, and finally 42 fitted the inclusion criteria. The Intra-class Correlation Coefficient (ICC) is the most popular method with 25 (60%) studies having used this method followed by the comparing means (8 or 19%). Out of 25 studies using the ICC, only 7 (28%) reported the confidence intervals and types of ICC used. Most studies (71%) also tested the agreement of instruments. This study finds that the Intra-class Correlation Coefficient is the most popular method used to assess the reliability of medical instruments measuring continuous outcomes. There are also inappropriate applications and interpretations of statistical methods in some studies. It is important for medical researchers to be aware of this issue, and be able to correctly perform analysis in reliability studies.

The Prevention of Surgical Site Infection in Elective Colon Surgery

PubMed Central

Fry, Donald E.

2013-01-01

Infections at the surgical site continue to occur in as many as 20% of elective colon resection cases. Methods to reduce these infections are inconsistently applied. Surgical site infection (SSI) is the result of multiple interactive variables including the inoculum of bacteria that contaminate the site, the virulence of the contaminating microbes, and the local environment at the surgical site. These variables that promote infection are potentially offset by the effectiveness of the host defense. Reduction in the inoculum of bacteria is achieved by appropriate surgical site preparation, systemic preventive antibiotics, and use of mechanical bowel preparation in conjunction with the oral antibiotic bowel preparation. Intraoperative reduction of hematoma, necrotic tissue, foreign bodies, and tissue dead space will reduce infections. Enhancement of the host may be achieved by perioperative supplemental oxygenation, maintenance of normothermia, and glycemic control. These methods require additional research to identify optimum application. Uniform application of currently understood methods and continued research into new methods to reduce microbial contamination and enhancement of host responsiveness can lead to better outcomes. PMID:24455434

Heralded processes on continuous-variable spaces as quantum maps

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

Ferreyrol, Franck; Spagnolo, Nicolò; Blandino, Rémi

2014-12-04

Heralding processes, which only work when a measurement on a part of the system give the good result, are particularly interesting for continuous-variables. They permit non-Gaussian transformations that are necessary for several continuous-variable quantum information tasks. However if maps and quantum process tomography are commonly used to describe quantum transformations in discrete-variable space, they are much rarer in the continuous-variable domain. Also, no convenient tool for representing maps in a way more adapted to the particularities of continuous variables have yet been explored. In this paper we try to fill this gap by presenting such a tool.

Evolution of association between renal and liver functions while awaiting heart transplant: An application using a bivariate multiphase nonlinear mixed effects model.

PubMed

Rajeswaran, Jeevanantham; Blackstone, Eugene H; Barnard, John

2018-07-01

In many longitudinal follow-up studies, we observe more than one longitudinal outcome. Impaired renal and liver functions are indicators of poor clinical outcomes for patients who are on mechanical circulatory support and awaiting heart transplant. Hence, monitoring organ functions while waiting for heart transplant is an integral part of patient management. Longitudinal measurements of bilirubin can be used as a marker for liver function and glomerular filtration rate for renal function. We derive an approximation to evolution of association between these two organ functions using a bivariate nonlinear mixed effects model for continuous longitudinal measurements, where the two submodels are linked by a common distribution of time-dependent latent variables and a common distribution of measurement errors.

Genetics and Genomics of Acute Neurologic Disorders.

PubMed

Maserati, Megan; Alexander, Sheila A

2018-01-01

Neurologic diseases and injuries are complex and multifactorial, making risk prediction, targeted treatment modalities, and outcome prognostication difficult and elusive. Genetics and genomics have affected clinical practice in many aspects in medicine, particularly cancer treatment. Advancements in knowledge of genetic and genomic variability in neurologic disease and injury are growing rapidly. Although these data are not yet ready for use in clinical practice, research continues to progress and elucidate information that eventually will provide answers to complex neurologic questions and serve as a platform to provide individualized care plans aimed at improving outcomes. This article provides a focused review of relevant literature on genetics, genomics, and common complex neurologic disease and injury likely to be seen in the acute care setting. ©2018 American Association of Critical-Care Nurses.

The effects and interactions of student, teacher, and setting variables on reading outcomes for kindergartners receiving supplemental reading intervention.

PubMed

Hagan-Burke, Shanna; Coyne, Michael D; Kwok, Oi-Man; Simmons, Deborah C; Kim, Minjung; Simmons, Leslie E; Skidmore, Susan T; Hernandez, Caitlin L; McSparran Ruby, Maureen

2013-01-01

This exploratory study examined the influences of student, teacher, and setting characteristics on kindergarteners' early reading outcomes and investigated whether those relations were moderated by type of intervention. Participants included 206 kindergarteners identified as at risk for reading difficulties and randomly assigned to one of two supplemental interventions: (a) an experimental explicit, systematic, code-based program or (b) their schools' typical kindergarten reading intervention. Results from separate multilevel structural equation models indicated that among student variables, entry-level alphabet knowledge was positively associated with phonemic and decoding outcomes in both conditions. Entry-level rapid automatized naming also positively influenced decoding outcomes in both conditions. However, its effect on phonemic outcomes was statistically significant only among children in the typical practice comparison condition. Regarding teacher variables, the quality of instruction was associated with significantly higher decoding outcomes in the typical reading intervention condition but had no statistically significant influence on phonemic outcomes in either condition. Among setting variables, instruction in smaller group sizes was associated with better phonemic outcomes in the comparison condition but had no statistically significant influence on outcomes of children in the intervention group. Mode of delivery (i.e., pullout vs. in class) had no statistically significant influence on either outcome variable.

Variable-Domain Functional Regression for Modeling ICU Data.

PubMed

Gellar, Jonathan E; Colantuoni, Elizabeth; Needham, Dale M; Crainiceanu, Ciprian M

2014-12-01

We introduce a class of scalar-on-function regression models with subject-specific functional predictor domains. The fundamental idea is to consider a bivariate functional parameter that depends both on the functional argument and on the width of the functional predictor domain. Both parametric and nonparametric models are introduced to fit the functional coefficient. The nonparametric model is theoretically and practically invariant to functional support transformation, or support registration. Methods were motivated by and applied to a study of association between daily measures of the Intensive Care Unit (ICU) Sequential Organ Failure Assessment (SOFA) score and two outcomes: in-hospital mortality, and physical impairment at hospital discharge among survivors. Methods are generally applicable to a large number of new studies that record a continuous variables over unequal domains.

Nonparametric Signal Extraction and Measurement Error in the Analysis of Electroencephalographic Activity During Sleep

PubMed Central

Crainiceanu, Ciprian M.; Caffo, Brian S.; Di, Chong-Zhi; Punjabi, Naresh M.

2009-01-01

We introduce methods for signal and associated variability estimation based on hierarchical nonparametric smoothing with application to the Sleep Heart Health Study (SHHS). SHHS is the largest electroencephalographic (EEG) collection of sleep-related data, which contains, at each visit, two quasi-continuous EEG signals for each subject. The signal features extracted from EEG data are then used in second level analyses to investigate the relation between health, behavioral, or biometric outcomes and sleep. Using subject specific signals estimated with known variability in a second level regression becomes a nonstandard measurement error problem. We propose and implement methods that take into account cross-sectional and longitudinal measurement error. The research presented here forms the basis for EEG signal processing for the SHHS. PMID:20057925

Outcomes in knowledge, attitudes and confidence of nursing staff working in nursing and residential care homes following a dementia training programme.

PubMed

Scerri, Anthony; Scerri, Charles

2017-11-08

Dementia training programmes for staff working in long-term care settings have been found to be effective in improving staff outcomes. This study investigated the impact of a dementia training programme for all Maltese nursing staff working in public nursing/residential homes on their knowledge, attitudes and confidence. Additionally, we identified the predictors of these domains before and after the programme. A 14-hour training programme focusing on dementia management, care and policy was developed for all nursing staff working in public nursing and residential homes in Malta. A pretest-posttest design was used to evaluate the participants' knowledge of dementia, attitudes and confidence in working with residents with dementia using validated tools. Demographic variables were measured and compared with each staff domain. The majority of nursing staff attended the training programme with 261 fully completed questionnaires being collected pre-training and 214 post-training. The programme significantly improved nursing staff knowledge, attitudes and confidence. Stepwise regression analysis of each staff domain showed that the strongest predictor in all models at pre-training was the intensity of previous training programmes. Furthermore, staff who attended previous training continued to improve in their attitudes and confidence following programme completion. The study continues to shed further evidence on the impact of dementia training programs on staff outcomes. It also indicated that the intensity of previous participation in dementia training programmes was related to the participants' knowledge, attitudes and confidence and that continual exposure to training had a cumulative effect.

Clinical outcome of continuous facial nerve monitoring during primary parotidectomy.

PubMed

Terrell, J E; Kileny, P R; Yian, C; Esclamado, R M; Bradford, C R; Pillsbury, M S; Wolf, G T

1997-10-01

To assess whether continuous facial nerve monitoring during parotidectomy is associated with a lower incidence of facial nerve paresis or paralysis compared with parotidectomy without monitoring and to assess the cost of such monitoring. A retrospective analysis of outcomes for patients who underwent parotidectomy with or without continuous facial nerve monitoring. University medical center. Fifty-six patients undergoing parotidectomy in whom continuous electromyographic monitoring was used and 61 patients in whom it was not used. (1) The incidence of early and persistent facial nerve paresis or paralysis and (2) the cost associated with facial nerve monitoring. Early, unintentional facial weakness was significantly lower in the group monitored by electromyograpy (43.6%) than in the unmonitored group (62.3%) (P=.04). In the subgroup of patients without comorbid conditions or surgeries, early weakness in the monitored group (33.3%) remained statistically lower than the rate of early weakness in the unmonitored group (57.5%) (P=.03). There was no statistical difference in the final facial nerve function or incidence of permanent nerve injury between the groups or subgroups. After multivariate analysis, nonmonitored status (odds ratio [OR], 3.22), advancing age (OR, 1.47 per 10 years), and longer operative times (OR, 1.3 per hour) were the only significant independent predictive variables significantly associated with early postoperative facial weakness. The incremental cost of facial nerve monitoring was $379. The results suggest that continuous electromyographic monitoring of facial muscle during primary parotidectomy reduces the incidence of short-term postoperative facial paresis. Advantages and disadvantages of this technique need to be considered together with the additional costs in deciding whether routine use of continuous monitoring is a useful, cost-effective adjunct to parotid surgery.

An analysis of the predictors of mortality and morbidity in patients admitted after suicidal hanging to an Indian multidisciplinary Intensive Care Unit

PubMed Central

Renuka, MK; Kalaiselvan, MS; Arunkumar, AS

2017-01-01

Background and Aims: Hanging is a frequently used method to attempt suicide in India. There is a lack of data in the Indian population regarding clinical features and outcomes of suicidal hanging. The purpose of this study was to evaluate the factors affecting mortality and morbidity in patients admitted with suicidal hanging to the Intensive Care Unit (ICU). Methods: A 6-year retrospective study of adult patients admitted to the ICU with suicidal hanging was analysed for demographics, mode of hanging, lead time to emergency room (ER) admission, clinical presentation, Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, admission Glasgow coma scale (GCS) and neurological outcomes. The primary outcome was in-hospital mortality rate. Secondary outcomes were hospital length of stay (LOS), ICU-LOS, time for neurological recovery, organ support and duration of mechanical ventilation. Statistical analysis was performed using the Student's t-test for continuous variables and Chi-square test for categorical variables. Results: We analysed data of 106 patients. The median age was 27 years [Interquartile Range (IQR) (22–34)]. The median lead time to ER admission was 1 h [IQR (0.5–1.4)] with median ICU stay of 3 days [IQR (2–4)]. Vasopressors were administered to 27.4% patients. GCS was ≤7 in 65% patients, and 84.9% patients received mechanical ventilation. Mortality rate was 10.3%. Survivors recovered with normal organ function. Conclusion: Suicidal hanging is associated with significant mortality. Admission GCS, APACHE II and 48 h SOFA score were predictors of poor outcome. PMID:28794524

Real time monitoring of risk-adjusted paediatric cardiac surgery outcomes using variable life-adjusted display: implementation in three UK centres

PubMed Central

Pagel, Christina; Utley, Martin; Crowe, Sonya; Witter, Thomas; Anderson, David; Samson, Ray; McLean, Andrew; Banks, Victoria; Tsang, Victor; Brown, Katherine

2013-01-01

Objective To implement routine in-house monitoring of risk-adjusted 30-day mortality following paediatric cardiac surgery. Design Collaborative monitoring software development and implementation in three specialist centres. Patients and methods Analyses incorporated 2 years of data routinely audited by the National Institute of Cardiac Outcomes Research (NICOR). Exclusion criteria were patients over 16 or undergoing non-cardiac or only catheter procedures. We applied the partial risk adjustment in surgery (PRAiS) risk model for death within 30 days following surgery and generated variable life-adjusted display (VLAD) charts for each centre. These were shared with each clinical team and feedback was sought. Results Participating centres were Great Ormond Street Hospital, Evelina Children's Hospital and The Royal Hospital for Sick Children in Glasgow. Data captured all procedures performed between 1 January 2010 and 31 December 2011. This incorporated 2490 30-day episodes of care, 66 of which were associated with a death within 30 days.The VLAD charts generated for each centre displayed trends in outcomes benchmarked to recent national outcomes. All centres ended the 2-year period within four deaths from what would be expected. The VLAD charts were shared in multidisciplinary meetings and clinical teams reported that they were a useful addition to existing quality assurance initiatives. Each centre is continuing to use the prototype software to monitor their in-house surgical outcomes. Conclusions Timely and routine monitoring of risk-adjusted mortality following paediatric cardiac surgery is feasible. Close liaison with hospital data managers as well as clinicians was crucial to the success of the project. PMID:23564473

Simpson's Paradox, Lord's Paradox, and Suppression Effects are the same phenomenon – the reversal paradox

PubMed Central

Tu, Yu-Kang; Gunnell, David; Gilthorpe, Mark S

2008-01-01

This article discusses three statistical paradoxes that pervade epidemiological research: Simpson's paradox, Lord's paradox, and suppression. These paradoxes have important implications for the interpretation of evidence from observational studies. This article uses hypothetical scenarios to illustrate how the three paradoxes are different manifestations of one phenomenon – the reversal paradox – depending on whether the outcome and explanatory variables are categorical, continuous or a combination of both; this renders the issues and remedies for any one to be similar for all three. Although the three statistical paradoxes occur in different types of variables, they share the same characteristic: the association between two variables can be reversed, diminished, or enhanced when another variable is statistically controlled for. Understanding the concepts and theory behind these paradoxes provides insights into some controversial or contradictory research findings. These paradoxes show that prior knowledge and underlying causal theory play an important role in the statistical modelling of epidemiological data, where incorrect use of statistical models might produce consistent, replicable, yet erroneous results. PMID:18211676

Assessing mediation using marginal structural models in the presence of confounding and moderation

PubMed Central

Coffman, Donna L.; Zhong, Wei

2012-01-01

This paper presents marginal structural models (MSMs) with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW can be used to take confounding into account, but IPW has several advantages. Regression adjustment of even one confounder of the mediator and outcome that has been influenced by treatment results in biased estimates of the direct effect (i.e., the effect of treatment on the outcome that does not go through the mediator). One advantage of IPW is that it can properly adjust for this type of confounding, assuming there are no unmeasured confounders. Further, we illustrate that IPW estimation provides unbiased estimates of all effects when there is a baseline moderator variable that interacts with the treatment, when there is a baseline moderator variable that interacts with the mediator, and when the treatment interacts with the mediator. IPW estimation also provides unbiased estimates of all effects in the presence of non-randomized treatments. In addition, for testing mediation we propose a test of the null hypothesis of no mediation. Finally, we illustrate this approach with an empirical data set in which the mediator is continuous, as is often the case in psychological research. PMID:22905648

Assessing mediation using marginal structural models in the presence of confounding and moderation.

PubMed

Coffman, Donna L; Zhong, Wei

2012-12-01

This article presents marginal structural models with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW can be used to take confounding into account, but IPW has several advantages. Regression adjustment of even one confounder of the mediator and outcome that has been influenced by treatment results in biased estimates of the direct effect (i.e., the effect of treatment on the outcome that does not go through the mediator). One advantage of IPW is that it can properly adjust for this type of confounding, assuming there are no unmeasured confounders. Further, we illustrate that IPW estimation provides unbiased estimates of all effects when there is a baseline moderator variable that interacts with the treatment, when there is a baseline moderator variable that interacts with the mediator, and when the treatment interacts with the mediator. IPW estimation also provides unbiased estimates of all effects in the presence of nonrandomized treatments. In addition, for testing mediation we propose a test of the null hypothesis of no mediation. Finally, we illustrate this approach with an empirical data set in which the mediator is continuous, as is often the case in psychological research. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Incremental change or initial differences? Testing two models of marital deterioration.

PubMed

Lavner, Justin A; Bradbury, Thomas N; Karney, Benjamin R

2012-08-01

Most couples begin marriage intent on maintaining a fulfilling relationship, but some newlyweds soon struggle, and others continue to experience high levels of satisfaction. Do these diverse outcomes result from an incremental process that unfolds over time, as prevailing models suggest, or are they a manifestation of initial differences that are largely evident at the start of the marriage? Using 8 waves of data collected over the first 4 years of marriage (N = 502 spouses, or 251 newlywed marriages), we tested these competing perspectives first by identifying 3 qualitatively distinct relationship satisfaction trajectory groups and then by determining the extent to which spouses in these groups were differentiated on the basis of (a) initial scores and (b) 4-year changes in a set of established predictor variables, including relationship problems, aggression, attributions, stress, and self-esteem. The majority of spouses exhibited high, stable satisfaction over the first 4 years of marriage, whereas declining satisfaction was isolated among couples with relatively low initial satisfaction. Across all predictor variables, initial values afforded stronger discrimination of outcome groups than did rates of change in these variables. Thus, readily measured initial differences are potent antecedents of relationship deterioration, and studies are now needed to clarify the specific ways in which initial indices of risk come to influence changes in spouses' judgments of relationship satisfaction. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Incremental Change or Initial Differences? Testing Two Models of Marital Deterioration

PubMed Central

Lavner, Justin A.; Bradbury, Thomas N.; Karney, Benjamin R.

2012-01-01

Most couples begin marriage intent on maintaining a fulfilling relationship, but some newlyweds soon struggle while others continue to experience high levels of satisfaction. Do these diverse outcomes result from an incremental process that unfolds over time, as prevailing models suggest, or are they a manifestation of initial differences that are largely evident at the start of the marriage? Using eight waves of data collected over the first 4 years of marriage (N = 502 spouses, or 251 newlywed marriages), we tested these competing perspectives first by identifying three qualitatively distinct relationship satisfaction trajectory groups and then by determining the extent to which spouses in these groups were differentiated on the basis of (a) initial scores and (b) 4-year changes in a set of established predictor variables, including relationship problems, aggression, attributions, stress, and self-esteem. The majority of spouses exhibited high, stable satisfaction over the first four years of marriage, whereas declining satisfaction was isolating among couples with relatively low initial satisfaction. Across all predictor variables, initial values afforded stronger discrimination of outcome groups than did rates of change in these variables. Thus, readily-measured initial differences are potent antecedents of relationship deterioration, and studies are now needed to clarify the specific ways in which initial indices of risk come to influence changes in spouses’ judgments of relationship satisfaction. PMID:22709260

Disorganized Symptoms Predicted Worse Functioning Outcome in Schizophrenia Patients with Established Illness.

PubMed

Ortiz, Bruno Bertolucci; Gadelha, Ary; Higuchi, Cinthia Hiroko; Noto, Cristiano; Medeiros, Daiane; Pitta, José Cássio do Nascimento; de Araújo Filho, Gerardo Maria; Hallak, Jaime Eduardo Cecílio; Bressan, Rodrigo Affonseca

Most patients with schizophrenia will have subsequent relapses of the disorder, with continuous impairments in functioning. However, evidence is lacking on how symptoms influence functioning at different phases of the disease. This study aims to investigate the relationship between symptom dimensions and functioning at different phases: acute exacerbation, nonremission and remission. Patients with schizophrenia were grouped into acutely ill (n=89), not remitted (n=89), and remitted (n=69). Three exploratory stepwise linear regression analyses were performed for each phase of schizophrenia, in which the five PANSS factors and demographic variables were entered as the independent variables and the total Global Assessment of Functioning Scale (GAF) score was entered as the dependent variable. An additional exploratory stepwise logistic regression analysis was performed to predict subsequent remission at discharge in the inpatient population. The Disorganized factor was the most significant predictor for acutely ill patients (p<0.001), while the Hostility factor was the most significant for not-remitted patients and the Negative factor was the most significant for remitted patients (p=0.001 and p<0.001, respectively). In the logistic regression, the Disorganized factor score presented a significant negative association with remission (p=0.007). Higher disorganization symptoms showed the greatest impact in functioning at acute phase, and prevented patients from achieving remission, suggesting it may be a marker of symptom severity and worse outcome in schizophrenia.

Comparison between splines and fractional polynomials for multivariable model building with continuous covariates: a simulation study with continuous response.

PubMed

Binder, Harald; Sauerbrei, Willi; Royston, Patrick

2013-06-15

In observational studies, many continuous or categorical covariates may be related to an outcome. Various spline-based procedures or the multivariable fractional polynomial (MFP) procedure can be used to identify important variables and functional forms for continuous covariates. This is the main aim of an explanatory model, as opposed to a model only for prediction. The type of analysis often guides the complexity of the final model. Spline-based procedures and MFP have tuning parameters for choosing the required complexity. To compare model selection approaches, we perform a simulation study in the linear regression context based on a data structure intended to reflect realistic biomedical data. We vary the sample size, variance explained and complexity parameters for model selection. We consider 15 variables. A sample size of 200 (1000) and R(2)  = 0.2 (0.8) is the scenario with the smallest (largest) amount of information. For assessing performance, we consider prediction error, correct and incorrect inclusion of covariates, qualitative measures for judging selected functional forms and further novel criteria. From limited information, a suitable explanatory model cannot be obtained. Prediction performance from all types of models is similar. With a medium amount of information, MFP performs better than splines on several criteria. MFP better recovers simpler functions, whereas splines better recover more complex functions. For a large amount of information and no local structure, MFP and the spline procedures often select similar explanatory models. Copyright © 2012 John Wiley & Sons, Ltd.

Phase Synchronization in Electroencephalographic Recordings Prognosticates Outcome in Paediatric Coma

PubMed Central

Nenadovic, Vera; Perez Velazquez, Jose Luis; Hutchison, James Saunders

2014-01-01

Brain injury from trauma, cardiac arrest or stroke is the most important cause of death and acquired disability in the paediatric population. Due to the lifetime impact of brain injury, there is a need for methods to stratify patient risk and ultimately predict outcome. Early prognosis is fundamental to the implementation of interventions to improve recovery, but no clinical model as yet exists. Healthy physiology is associated with a relative high variability of physiologic signals in organ systems. This was first evaluated in heart rate variability research. Brain variability can be quantified through electroencephalographic (EEG) phase synchrony. We hypothesised that variability in brain signals from EEG recordings would correlate with patient outcome after brain injury. Lower variability in EEG phase synchronization, would be associated with poor patient prognosis. A retrospective study, spanning 10 years (2000–2010) analysed the scalp EEGs of children aged 1 month to 17 years in coma (Glasgow Coma Scale, GCS, <8) admitted to the paediatric critical care unit (PCCU) following brain injury from TBI, cardiac arrest or stroke. Phase synchrony of the EEGs was evaluated using the Hilbert transform and the variability of the phase synchrony calculated. Outcome was evaluated using the 6 point Paediatric Performance Category Score (PCPC) based on chart review at the time of hospital discharge. Outcome was dichotomized to good outcome (PCPC score 1 to 3) and poor outcome (PCPC score 4 to 6). Children who had a poor outcome following brain injury secondary to cardiac arrest, TBI or stroke, had a higher magnitude of synchrony (R index), a lower spatial complexity of the synchrony patterns and a lower temporal variability of the synchrony index values at 15 Hz when compared to those patients with a good outcome. PMID:24752289

Multivariate Bayesian variable selection exploiting dependence structure among outcomes: Application to air pollution effects on DNA methylation.

PubMed

Lee, Kyu Ha; Tadesse, Mahlet G; Baccarelli, Andrea A; Schwartz, Joel; Coull, Brent A

2017-03-01

The analysis of multiple outcomes is becoming increasingly common in modern biomedical studies. It is well-known that joint statistical models for multiple outcomes are more flexible and more powerful than fitting a separate model for each outcome; they yield more powerful tests of exposure or treatment effects by taking into account the dependence among outcomes and pooling evidence across outcomes. It is, however, unlikely that all outcomes are related to the same subset of covariates. Therefore, there is interest in identifying exposures or treatments associated with particular outcomes, which we term outcome-specific variable selection. In this work, we propose a variable selection approach for multivariate normal responses that incorporates not only information on the mean model, but also information on the variance-covariance structure of the outcomes. The approach effectively leverages evidence from all correlated outcomes to estimate the effect of a particular covariate on a given outcome. To implement this strategy, we develop a Bayesian method that builds a multivariate prior for the variable selection indicators based on the variance-covariance of the outcomes. We show via simulation that the proposed variable selection strategy can boost power to detect subtle effects without increasing the probability of false discoveries. We apply the approach to the Normative Aging Study (NAS) epigenetic data and identify a subset of five genes in the asthma pathway for which gene-specific DNA methylations are associated with exposures to either black carbon, a marker of traffic pollution, or sulfate, a marker of particles generated by power plants. © 2016, The International Biometric Society.

Dealing with missing standard deviation and mean values in meta-analysis of continuous outcomes: a systematic review.

PubMed

Weir, Christopher J; Butcher, Isabella; Assi, Valentina; Lewis, Stephanie C; Murray, Gordon D; Langhorne, Peter; Brady, Marian C

2018-03-07

Rigorous, informative meta-analyses rely on availability of appropriate summary statistics or individual participant data. For continuous outcomes, especially those with naturally skewed distributions, summary information on the mean or variability often goes unreported. While full reporting of original trial data is the ideal, we sought to identify methods for handling unreported mean or variability summary statistics in meta-analysis. We undertook two systematic literature reviews to identify methodological approaches used to deal with missing mean or variability summary statistics. Five electronic databases were searched, in addition to the Cochrane Colloquium abstract books and the Cochrane Statistics Methods Group mailing list archive. We also conducted cited reference searching and emailed topic experts to identify recent methodological developments. Details recorded included the description of the method, the information required to implement the method, any underlying assumptions and whether the method could be readily applied in standard statistical software. We provided a summary description of the methods identified, illustrating selected methods in example meta-analysis scenarios. For missing standard deviations (SDs), following screening of 503 articles, fifteen methods were identified in addition to those reported in a previous review. These included Bayesian hierarchical modelling at the meta-analysis level; summary statistic level imputation based on observed SD values from other trials in the meta-analysis; a practical approximation based on the range; and algebraic estimation of the SD based on other summary statistics. Following screening of 1124 articles for methods estimating the mean, one approximate Bayesian computation approach and three papers based on alternative summary statistics were identified. Illustrative meta-analyses showed that when replacing a missing SD the approximation using the range minimised loss of precision and generally performed better than omitting trials. When estimating missing means, a formula using the median, lower quartile and upper quartile performed best in preserving the precision of the meta-analysis findings, although in some scenarios, omitting trials gave superior results. Methods based on summary statistics (minimum, maximum, lower quartile, upper quartile, median) reported in the literature facilitate more comprehensive inclusion of randomised controlled trials with missing mean or variability summary statistics within meta-analyses.

How Does Patient Safety Culture in the Surgical Departments Compare to the Rest of the County Hospitals in Xiaogan City of China?

PubMed Central

Wang, Manli; Tao, Hongbing

2017-01-01

Objectives: Patient safety culture affects patient safety and the performance of hospitals. The Hospital Survey on Patient Safety Culture (HSOPSC) is generally used to assess the safety culture in hospitals and unit levels. However, only a few studies in China have measured surgical settings compared with other units in county hospitals using the HSOPSC. This study aims to assess the strengths and weaknesses of surgical departments compared with all other departments in county hospitals in China with HSOPSC. Design: This research is a cross-sectional study. Methods: In 2015, a Chinese translation of HSOPSC was administered to 1379 staff from sampled departments from 19 county hospitals in Xiaogan City (Hubei Province, China) using a simple random and cluster sampling method. Outcome Measures: The HSOPSC was completed by 1379 participants. The percent positive ratings (PPRs) of 12 dimensions (i.e., teamwork within units, organizational learning and continuous improvement, staffing, non-punitive response to errors, supervisor/ manager expectations and actions promoting patient safety, feedback and communication about errors, communication openness, hospital handoffs and transitions, teamwork across hospital units, hospital management support for patient safety, overall perception of safety, as well as frequency of events reported) and the positive proportion of outcome variables (patient safety grade and number of events reported) between surgical departments and other departments were compared with t-tests and X2 tests, respectively. A multiple regression analysis was conducted, with the outcome dimensions serving as dependent variables and basic characteristics and other dimensions serving as independent variables. Similarly, ordinal logistic regression was used to explore the influencing factors of two categorical outcomes. Results: A total of 56.49% of respondents were from surgical departments. The PPRs for “teamwork within units” and “organizational learning and continuous improvement” were ≥75%, which denoted strengths, and the PPRs for “staffing” and “non-punitive response to errors” were ≤50%, which denoted weaknesses in surgical units and other units. Three dimensions for surgical departments were weaker than those for other departments (p < 0.05). The staff from surgical units reported more events compared with the other units, but only a few respondents in surgical settings evaluated patient safety grade as good/excellent. Four dimensions influenced patient safety grade, and three dimensions influenced event reporting in surgical units. Conclusions: Strategies including recruiting workers, using the reporting system, and building a non-punitive culture should be adopted in the surgical units of county hospitals in China to improve safety culture. Supervisors should also prioritise patient safety. PMID:28954427

Outcome of TVT operations in women with low maximum urethral closure pressure.

PubMed

Moe, Kjartan; Schiøtz, Hjalmar A; Kulseng-Hanssen, Sigurd

2017-06-01

(i) To establish whether low maximal urethral closure pressure (MUCP) is associated with a poorer prognosis after TVT-surgery, and if so to establish an MUCP cut-off value for poor outcome. (ii) To characterize the population with a low MUCP. Retrospective analysis of data from 6,646 women with stress/mixed urinary incontinence included in the Norwegian Female Incontinence Registry. Postoperative subjective (degree of satisfaction), objective (leakage on stress test) and composite cure according to preoperative MUCP were analyzed in unadjusted and adjusted analysis. Preoperative variables were compared between women having a low or normal MUCP. Non-parametric tests were used on continuous variables and χ 2 tests on categorical variables. Logistic regression was used for the adjusted analysis. Level of significance: P < 0.05. An analysis of centiles of preoperative MUCP showed that a cut-off at 20 cm H 2 O did best identify women at risk of not being cured. In unadjusted analysis MUCP ≤20 cm H 2 O (n = 422) was associated with objective (OR: 2.48), subjective (OR: 1.60), and composite failure (OR: 1.95) compared to MUCP >20 cm H 2 O. In adjusted analysis MUCP ≤20 cm H 2 O was associated with neither objective, subjective, nor composite failure. Women with MUCP <20 cm H 2 O were preoperatively significantly older, had larger leakage on stress and 24 h pad test, lower mean voided volume and maximum flow rate and higher stress and urge indices. Women with MUCP ≤20 cm H 2 O have similar objective, subjective, and composite outcomes after TVT-surgery compared to women with MUCP >20 cm H 2 O after adjusting for preoperative variables. Neurourol. Urodynam. 36:1320-1324, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Glucose variability negatively impacts long-term functional outcome in patients with traumatic brain injury.

PubMed

Matsushima, Kazuhide; Peng, Monica; Velasco, Carlos; Schaefer, Eric; Diaz-Arrastia, Ramon; Frankel, Heidi

2012-04-01

Significant glycemic excursions (so-called glucose variability) affect the outcome of generic critically ill patients but has not been well studied in patients with traumatic brain injury (TBI). The purpose of this study was to evaluate the impact of glucose variability on long-term functional outcome of patients with TBI. A noncomputerized tight glucose control protocol was used in our intensivist model surgical intensive care unit. The relationship between the glucose variability and long-term (a median of 6 months after injury) functional outcome defined by extended Glasgow Outcome Scale (GOSE) was analyzed using ordinal logistic regression models. Glucose variability was defined by SD and percentage of excursion (POE) from the preset range glucose level. A total of 109 patients with TBI under tight glucose control had long-term GOSE evaluated. In univariable analysis, there was a significant association between lower GOSE score and higher mean glucose, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL but not POE 80 to 110. After adjusting for possible confounding variables in multivariable ordinal logistic regression models, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL were significantly associated with lower GOSE score. Glucose variability was significantly associated with poorer long-term functional outcome in patients with TBI as measured by the GOSE score. Well-designed protocols to minimize glucose variability may be key in improving long-term functional outcome. Copyright © 2012 Elsevier Inc. All rights reserved.

Continuous-variable quantum homomorphic signature

NASA Astrophysics Data System (ADS)

Li, Ke; Shang, Tao; Liu, Jian-wei

2017-10-01

Quantum cryptography is believed to be unconditionally secure because its security is ensured by physical laws rather than computational complexity. According to spectrum characteristic, quantum information can be classified into two categories, namely discrete variables and continuous variables. Continuous-variable quantum protocols have gained much attention for their ability to transmit more information with lower cost. To verify the identities of different data sources in a quantum network, we propose a continuous-variable quantum homomorphic signature scheme. It is based on continuous-variable entanglement swapping and provides additive and subtractive homomorphism. Security analysis shows the proposed scheme is secure against replay, forgery and repudiation. Even under nonideal conditions, it supports effective verification within a certain verification threshold.

Diagnostic accuracy and receiver-operating characteristics curve analysis in surgical research and decision making.

PubMed

Søreide, Kjetil; Kørner, Hartwig; Søreide, Jon Arne

2011-01-01

In surgical research, the ability to correctly classify one type of condition or specific outcome from another is of great importance for variables influencing clinical decision making. Receiver-operating characteristic (ROC) curve analysis is a useful tool in assessing the diagnostic accuracy of any variable with a continuous spectrum of results. In order to rule a disease state in or out with a given test, the test results are usually binary, with arbitrarily chosen cut-offs for defining disease versus health, or for grading of disease severity. In the postgenomic era, the translation from bench-to-bedside of biomarkers in various tissues and body fluids requires appropriate tools for analysis. In contrast to predetermining a cut-off value to define disease, the advantages of applying ROC analysis include the ability to test diagnostic accuracy across the entire range of variable scores and test outcomes. In addition, ROC analysis can easily examine visual and statistical comparisons across tests or scores. ROC is also favored because it is thought to be independent from the prevalence of the condition under investigation. ROC analysis is used in various surgical settings and across disciplines, including cancer research, biomarker assessment, imaging evaluation, and assessment of risk scores.With appropriate use, ROC curves may help identify the most appropriate cutoff value for clinical and surgical decision making and avoid confounding effects seen with subjective ratings. ROC curve results should always be put in perspective, because a good classifier does not guarantee the expected clinical outcome. In this review, we discuss the fundamental roles, suggested presentation, potential biases, and interpretation of ROC analysis in surgical research.

Study for Promotion of Health in Recycling Lead - Rationale and design.

PubMed

Hara, Azusa; Gu, Yu-Mei; Petit, Thibault; Liu, Yan-Ping; Jacobs, Lotte; Zhang, Zhen-Yu; Yang, Wen-Yi; Jin, Yu; Thijs, Lutgarde; Wei, Fang-Fei; Nawrot, Tim S; Staessen, Jan A

2015-06-01

The level at which low-level lead exposure produces subclinical adverse health effects in adults remains to be established. The Study for Promotion of Health in Recycling Lead (SPHERL) will enroll 500 newly hired workers, whose blood lead during 2 years of follow-up is expected to increase from levels less than 2 μg/dl, as currently observed in the US population, to 20-30 μg/dl. The main outcome variables to be studied are (i) blood pressure (BP) analyzed as a continuous or categorical variable, both cross-sectionally and longitudinally, and using conventional and ambulatory BP measurement; (ii) indexes of glomerular and tubular renal function, (iii) heart rate variability analyzed in the frequency domain as measure of autonomous sympathetic modulation, (iv) peripheral nerve conductivity velocity, (v) neurocognitive performance, and (vi) quality of life. Expected outcomes. Assuming a 10-fold increase in blood lead, SPHERL will have sufficient statistical power to detect over 2 years a steepening of the age-related rise in systolic BP from 1 to 5 mmHg and a doubling of the age-related decline in the estimated glomerular filtration rate from 3.5 to 7.0 ml/min/1.73 m(2). The longitudinal design of our study complies with the temporality principle of the Bradford-Hill criteria for assessing possible causality between outcomes and exposure. SPHERL will attempt to resolve the apparent contradiction between general population studies showing associations between adverse health effects and low lead exposure with blood lead levels below 5 μg/dl and studies conducted in occupational cohorts indicating that adverse effects of lead exposure occur at much higher blood lead levels.

Smoking in pregnancy in West Virginia: does cessation/reduction improve perinatal outcomes?

PubMed

Seybold, Dara J; Broce, Mike; Siegel, Eric; Findley, Joseph; Calhoun, Byron C

2012-01-01

To determine if pregnant women decreasing/quitting tobacco use will have improved fetal outcomes. Retrospective analysis of pregnant smokers from 6/1/2006-12/31/2007 who received prenatal care and delivered at a tertiary medical care center in West Virginia. Variables analyzed included birth certificate data linked to intervention program survey data. Patients were divided into four study groups: <8 cigarettes/day-no reduction, <8 cigarettes/day-reduction, ≥8 cigarettes/day-no reduction, and ≥8 cigarettes/day-reduction. Analysis performed using ANOVA one-way test for continuous variables and Chi-square for categorical variables. Inclusion criteria met by 250 patients. Twelve women (4.8%) quit smoking; 150 (60%) reduced; 27 (10.8%) increased; and 61 (24.4%) had no change. Comparing the four study groups for pre-term births (<37 weeks), 25% percent occurred in ≥8 no reduction group while 10% occurred in ≥8 with reduction group (P = 0.026). The high rate of preterm birth (25%) in the non-reducing group depended on 2 factors: (1) ≥8 cigarettes/day at beginning and (2) no reduction by the end of prenatal care. Finally, there was a statistically significant difference in birth weights between the two groups: ≥8 cigarettes/day with no reduction (2,872.6 g) versus <8 cigarettes/day with reduction (3,212.4 g) (P = 0.028). Smoking reduction/cessation lowered risk of pre-term delivery (<37 weeks) twofold. Encouraging patients who smoke ≥8 cigarettes/day during pregnancy to decrease/quit prior to delivery provides significant clinical benefit by decreasing the likelihood of preterm birth. These findings support tobacco cessation efforts as a means to improve birth outcome.

Predicting change over time in career planning and career exploration for high school students.

PubMed

Creed, Peter A; Patton, Wendy; Prideaux, Lee-Ann

2007-06-01

This study assessed 166 high school students in Grade 8 and again in Grade 10. Four models were tested: (a) whether the T1 predictor variables (career knowledge, indecision, decision-making self efficacy, self-esteem, demographics) predicted the outcome variable (career planning/exploration) at T1; (b) whether the T1 predictor variables predicted the outcome variable at T2; (c) whether the T1 predictor variables predicted change in the outcome variable from T1-T2; and (d) whether changes in the predictor variables from T1-T2 predicted change in the outcome variable from T1-T2. Strong associations (R(2)=34%) were identified for the T1 analysis (confidence, ability and paid work experience were positively associated with career planning/exploration). T1 variables were less useful predictors of career planning/exploration at T2 (R(2)=9%; having more confidence at T1 was associated with more career planning/exploration at T2) and change in career planning/exploration from T1-T2 (R(2)=11%; less confidence and no work experience were associated with change in career planning/exploration from T1-T2). When testing effect of changes in predictor variables predicting changes in outcome variable (R(2)=22%), three important predictors, indecision, work experience and confidence, were identified. Overall, results indicated important roles for self-efficacy and early work experiences in current and future career planning/exploration of high school students.

Delta Scuti Variables

NASA Astrophysics Data System (ADS)

Handler, Gerald

2009-09-01

We review recent research on Delta Scuti stars from an observer's viewpoint. First, some signposts helping to find the way through the Delta Scuti jungle are placed. Then, some problems in studying individual pulsators in the framework of asteroseismology are given before a view on how the study of these variables has benefited (or not) from past and present high-precision asteroseismic space missions is presented. Some possible pitfalls in the analysis of data with a large dynamical range in pulsational amplitudes are pointed out, and a strategy to optimize the outcome of asteroseismic studies of Delta Scuti stars is suggested. We continue with some views on ``hybrid'' pulsators and interesting individual High Amplitude Delta Scuti stars, and then take a look on Delta Scuti stars in stellar systems of several different kinds. Recent results on pre-main sequence Delta Scuti stars are discussed as are questions related to the instability strip of these variables. Finally, some remarkable new theoretical results are highlighted before, instead of a set of classical conclusions, questions to be solved in the future, are raised.

Waist circumference, body mass index, and employment outcomes.

PubMed

Kinge, Jonas Minet

2017-07-01

Body mass index (BMI) is an imperfect measure of body fat. Recent studies provide evidence in favor of replacing BMI with waist circumference (WC). Hence, I investigated whether or not the association between fat mass and employment status vary by anthropometric measures. I used 15 rounds of the Health Survey for England (1998-2013), which has measures of employment status in addition to measured height, weight, and WC. WC and BMI were entered as continuous variables and obesity as binary variables defined using both WC and BMI. I used multivariate models controlling for a set of covariates. The association of WC with employment was of greater magnitude than the association between BMI and employment. I reran the analysis using conventional instrumental variables methods. The IV models showed significant impacts of obesity on employment; however, they were not more pronounced when WC was used to measure obesity, compared to BMI. This means that, in the IV models, the impact of fat mass on employment did not depend on the measure of fat mass.

Intoxication by star fruit (Averrhoa carambola) in 32 uraemic patients: treatment and outcome.

PubMed

Neto, Miguel Moyses; da Costa, José Abrão Cardeal; Garcia-Cairasco, Norberto; Netto, Joaquim Coutinho; Nakagawa, Beatriz; Dantas, Marcio

2003-01-01

Clinical symptoms and outcomes of uraemic patients ingesting star fruit are quite variable and may progress to death. The purpose of the present report was to discuss the neurotoxic effects of star fruit intoxication in uraemic patients and to present the efficacy of different therapeutic approaches. We studied a total of 32 uraemic patients who had ingested star fruit. Before the intoxication episodes, 20 patients were on regular haemodialysis, eight were on peritoneal dialysis and four were not yet undergoing dialysis. Two patients were analysed retrospectively from their charts, 17 were directly monitored by our clinic and 13 were referred by physicians from many areas throughout the country, allowing us to follow their outcome from a distance. Intoxicated patients were given different therapeutic approaches (haemodialysis, peritoneal dialysis and supportive treatment), and their outcomes were analysed. The most common symptoms were persistent and intractable hiccups in 30 patients (93.75%), vomiting in 22 (68.7%), variable degrees of disturbed consciousness (mental confusion, psychomotor agitation) in 21 (65.6%), decreased muscle power, limb numbness, paresis, insomnia and paresthesias in 13 (40.6%) and seizures in seven (21.8%). Patients who were promptly treated with haemodialysis, including those with severe intoxication, recovered without sequelae. Patients with severe intoxication who were not treated or treated with peritoneal dialysis did not survive. Haemodialysis, especially on a daily basis, is the ideal treatment for star fruit intoxication. In severe cases, continuous methods of replacement therapy may provide a superior initial procedure, since rebound effects are a common event. Peritoneal dialysis is of no use as a treatment, especially when consciousness disorders ensue.

Complete versus partial preservation of mitral valve apparatus during mitral valve replacement: meta-analysis and meta-regression of 1535 patients.

PubMed

Sá, Michel Pompeu Barros De Oliveira; Escobar, Rodrigo Renda; Ferraz, Paulo Ernando; Vasconcelos, Frederico Pires; Lima, Ricardo Carvalho

2013-11-01

To determine if there is any real difference between complete preservation (CP) and partial preservation (PP) of the mitral valve apparatus during mitral valve replacement (MVR) in terms of hard outcomes. MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar and reference lists of relevant articles were searched for clinical studies that compared outcomes [30-day mortality, postoperative low cardiac output syndrome (LCOS), 5-year mortality or left ventricle ejection fraction (LVEF) before and after surgery] between MVR-CP vs MVR-PP during MVR until July 2012. The principal summary measures were odds ratios (ORs) with 95% confidence interval (CI)--for categorical variables (30-day mortality, postoperative LCOS, 5-year mortality); difference means and standard error (SE)--for continuous variables (LVEF before and after surgery) and P values (that will be considered statistically significant when <0.05). The ORs were combined across studies using DerSimonian-Laird random effects weighted model. The same procedure was executed for continuous variables, taking into consideration the difference in means. Eight studies (2 randomized and 6 non-randomized) were identified and included a total of 1535 patients (597 for MVR-CP and 938 for MVR-PP). There was no significant difference between MVR-CP or MVR-PP groups in the risk for 30-day mortality (OR 0.870; 95% CI 0.50-1.52; P = 0.63) or postoperative LCOS (OR 0.35; 95% CI 0.11-1.08 and P = 0.07) or 5-year mortality (OR 0.70; 95% CI 0.43-1.14; P = 0.15). Taking into consideration LVEF, neither MVR-CP nor MVR-CP demonstrated a statistically significant improvement in LVEF before and after surgery, and both strategies were not different from each other. No publication bias was observed. We found evidence that argues against any superiority between both techniques of preservation (complete or partial) of mitral valve apparatus during MVR.

Student Self-Reported Learning Outcomes of Field Trips: The pedagogical impact

NASA Astrophysics Data System (ADS)

Lavie Alon, Nirit; Tal, Tali

2015-05-01

In this study, we used the classification and regression trees (CART) method to draw relationships between student self-reported learning outcomes in 26 field trips to natural environments and various characteristics of the field trip that include variables associated with preparation and pedagogy. We wished to examine the extent to which the preparation for the field trip, its connection to the school curriculum, and the pedagogies used, affect students' self-reported outcomes in three domains: cognitive, affective, and behavioral; and the extent the students' socioeconomic group and the guide's affiliation affect students' reported learning outcomes. Given that most of the field trips were guide-centered, the most important variable that affected the three domains of outcomes was the guide's storytelling. Other variables that showed relationships with self-reported outcomes were physical activity and making connections to everyday life-all of which we defined as pedagogical variables. We found no significant differences in student self-reported outcomes with respect to their socioeconomic group and the guide's organizational affiliation.

Improving work environments in health care: test of a theoretical framework.

PubMed

Rathert, Cheryl; Ishqaidef, Ghadir; May, Douglas R

2009-01-01

In light of high levels of staff turnover and variability in the quality of health care, much attention is currently being paid to the health care work environment and how it potentially relates to staff, patient, and organizational outcomes. Although some attention has been paid to staffing variables, more attention must be paid to improving the work environment for patient care. The purpose of this study was to empirically explore a theoretical model linking the work environment in the health care setting and how it might relate to work engagement, organizational commitment, and patient safety. This study also explored how the work environment influences staff psychological safety, which has been show to influence several variables important in health care. Clinical care providers at a large metropolitan hospital were surveyed using a mail methodology. The overall response rate was 42%. This study analyzed perceptions of staff who provided direct care to patients. Using structural equation modeling, we found that different dimensions of the work environment were related to different outcome variables. For example, a climate for continuous quality improvement was positively related to organizational commitment and patient safety, and psychological safety partially mediated these relationships. Patient-centered care was positively related to commitment but negatively related to engagement. Health care managers need to examine how organizational policies and practices are translated into the work environment and how these influence practices on the front lines of care. It appears that care provider perceptions of their work environments may be useful to consider for improvement efforts.

Physiological and behavioral indices of emotion dysregulation as predictors of outcome from cognitive behavioral therapy and acceptance and commitment therapy for anxiety.

PubMed

Davies, Carolyn D; Niles, Andrea N; Pittig, Andre; Arch, Joanna J; Craske, Michelle G

2015-03-01

Identifying for whom and under what conditions a treatment is most effective is an essential step toward personalized medicine. The current study examined pre-treatment physiological and behavioral variables as predictors and moderators of outcome in a randomized clinical trial comparing cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) for anxiety disorders. Sixty individuals with a DSM-IV defined principal anxiety disorder completed 12 sessions of either CBT or ACT. Baseline physiological and behavioral variables were measured prior to entering treatment. Self-reported anxiety symptoms were assessed at pre-treatment, post-treatment, and 6- and 12-month follow-up from baseline. Higher pre-treatment heart rate variability was associated with worse outcome across ACT and CBT. ACT outperformed CBT for individuals with high behavioral avoidance. Subjective anxiety levels during laboratory tasks did not predict or moderate treatment outcome. Due to small sample sizes of each disorder, disorder-specific predictors were not tested. Future research should examine these predictors in larger samples and across other outcome variables. Lower heart rate variability was identified as a prognostic indicator of overall outcome, whereas high behavioral avoidance was identified as a prescriptive indicator of superior outcome from ACT versus CBT. Investigation of pre-treatment physiological and behavioral variables as predictors and moderators of outcome may help guide future treatment-matching efforts. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Role and Impact of Animals with Pediatric Patients.

PubMed

Goddard, Anna Tielsch; Gilmer, Mary Jo

2015-01-01

Animal-facilitated therapy (AFT), more specifically known as animal-assisted therapy (AAT) or "pet therapy," has had an increased presence in the literature with a surge of recent research methodologies exploring this complementary alternative medicine (CAM) intervention. However, limited studies have been conducted in the pediatric population, with many articles anecdotal in nature. A literature review included primary data sources PubMed, PsychINFO, Medline, and CINAHL, and yielded positive and beneficial outcomes to be gained through AAT in the pediatric population. Primary outcome variables of decreased anxiety and pain are the most commonly reported results. Further research studies are indicated to include the effects of AFT with children with different diseases and diagnoses. Exploration of other psychosocial and physical variables, such as self-esteem, would be useful. Interdisciplinary strategies are needed to develop interventions to help reduce patient symptoms and treatment-associated stress, as well as to facilitate healing and wellness beyond traditional medical treatment plans. Complementary therapies are of continued interest to the health care community, especially for pediatric nurses. Effective use of animals to facilitate conversation, lead discussion, or break communication barriers has been demonstrated through both research and anecdotal reports.

Attention deficits after aneurysmal subarachnoid hemorrhage measured using the test of variables of attention.

PubMed

Wallmark, Svante; Lundström, Erik; Wikström, Johan; Ronne-Engström, Elisabeth

2015-05-01

The aim of this pilot study was to assess attention deficits in patients with aneurysmal subarachnoid hemorrhage using the test of variables of attention (TOVA). This is a computer-based continuous performance test providing objective measures of attention. We also compared the TOVA results with the attention and concentration domains of Montgomery Åsberg Depression Rating Scale and Montreal cognitive assessment, 2 examiner-administrated neuropsychological instruments. Nineteen patients with moderate to good recovery (Glasgow outcome scale, 4-5) were assessed using the TOVA, Montgomery Åsberg Depression Rating Scale, and Montreal cognitive assessment. The measurements were done when the patients visited the hospital for a routine magnetic resonance imaging control of the aneurysm. TOVA performance was pathological in 58%. The dominating pattern was a worsening of performance in the second half of the test, commonly a failing to react to correct stimuli. We found no correlation between TOVA and the performance in concentration and attention domains of Montgomery Åsberg Depression Rating Scale and Montreal cognitive assessment. Attention deficits, measured by the TOVA, were common after subarachnoid hemorrhage. This should be further studied to improve outcome. © 2015 American Heart Association, Inc.

Second trimester maternal urine for the diagnosis of trisomy 21 and prediction of poor pregnancy outcomes.

PubMed

Diaz, Sílvia O; Barros, António S; Goodfellow, Brian J; Duarte, Iola F; Galhano, Eulália; Pita, Cristina; Almeida, Maria do Céu; Carreira, Isabel M; Gil, Ana M

2013-06-07

Given the recognized lack of prenatal clinical methods for the early diagnosis of preterm delivery, intrauterine growth restriction, preeclampsia and gestational diabetes mellitus, and the continuing need for optimized diagnosis methods for specific chromosomal disorders (e.g., trisomy 21) and fetal malformations, this work sought specific metabolic signatures of these conditions in second trimester maternal urine, using (1)H Nuclear Magnetic Resonance ((1)H NMR) metabolomics. Several variable importance to the projection (VIP)- and b-coefficient-based variable selection methods were tested, both individually and through their intersection, and the resulting data sets were analyzed by partial least-squares discriminant analysis (PLS-DA) and submitted to Monte Carlo cross validation (MCCV) and permutation tests to evaluate model predictive power. The NMR data subsets produced significantly improved PLS-DA models for all conditions except for pre-premature rupture of membranes. Specific urinary metabolic signatures were unveiled for central nervous system malformations, trisomy 21, preterm delivery, gestational diabetes, intrauterine growth restriction and preeclampsia, and biochemical interpretations were proposed. This work demonstrated, for the first time, the value of maternal urine profiling as a complementary means of prenatal diagnostics and early prediction of several poor pregnancy outcomes.

Violence and Disorder, School Climate, and PBIS: The Relationship among School Climate, Student Outcomes, and the Use of Positive Behavioral Interventions and Supports

ERIC Educational Resources Information Center

Eacho, Thomas Christopher

2013-01-01

The primary purpose of this study was to examine the relationship between school climate and student outcome variables. The secondary purpose was to examine the relationship between the use of Positive Behavioral Interventions and Supports (PBIS) and the same student outcome variables. Variables depicting student perceptions of school climate,…

The Causal Effects of Father Absence

PubMed Central

McLanahan, Sara; Tach, Laura; Schneider, Daniel

2014-01-01

The literature on father absence is frequently criticized for its use of cross-sectional data and methods that fail to take account of possible omitted variable bias and reverse causality. We review studies that have responded to this critique by employing a variety of innovative research designs to identify the causal effect of father absence, including studies using lagged dependent variable models, growth curve models, individual fixed effects models, sibling fixed effects models, natural experiments, and propensity score matching models. Our assessment is that studies using more rigorous designs continue to find negative effects of father absence on offspring well-being, although the magnitude of these effects is smaller than what is found using traditional cross-sectional designs. The evidence is strongest and most consistent for outcomes such as high school graduation, children’s social-emotional adjustment, and adult mental health. PMID:24489431

A trial of scheduled deep brain stimulation for Tourette syndrome: moving away from continuous deep brain stimulation paradigms.

PubMed

Okun, Michael S; Foote, Kelly D; Wu, Samuel S; Ward, Herbert E; Bowers, Dawn; Rodriguez, Ramon L; Malaty, Irene A; Goodman, Wayne K; Gilbert, Donald M; Walker, Harrison C; Mink, Jonathan W; Merritt, Stacy; Morishita, Takashi; Sanchez, Justin C

2013-01-01

To collect the information necessary to design the methods and outcome variables for a larger trial of scheduled deep brain stimulation (DBS) for Tourette syndrome. We performed a small National Institutes of Health-sponsored clinical trials planning study of the safety and preliminary efficacy of implanted DBS in the bilateral centromedian thalamic region. The study used a cranially contained constant-current device and a scheduled, rather than the classic continuous, DBS paradigm. Baseline vs 6-month outcomes were collected and analyzed. In addition, we compared acute scheduled vs acute continuous vs off DBS. A university movement disorders center. Five patients with implanted DBS. A 50% improvement in the Yale Global Tic Severity Scale (YGTSS) total score. RESULTS Participating subjects had a mean age of 34.4 (range, 28-39) years and a mean disease duration of 28.8 years. No significant adverse events or hardware-related issues occurred. Baseline vs 6-month data revealed that reductions in the YGTSS total score did not achieve the prestudy criterion of a 50% improvement in the YGTSS total score on scheduled stimulation settings. However, statistically significant improvements were observed in the YGTSS total score (mean [SD] change, -17.8 [9.4]; P=.01), impairment score (-11.3 [5.0]; P=.007), and motor score (-2.8 [2.2]; P=.045); the Modified Rush Tic Rating Scale Score total score (-5.8 [2.9]; P=.01); and the phonic tic severity score (-2.2 [2.6]; P=.04). Continuous, off, and scheduled stimulation conditions were assessed blindly in an acute experiment at 6 months after implantation. The scores in all 3 conditions showed a trend for improvement. Trends for improvement also occurred with continuous and scheduled conditions performing better than the off condition. Tic suppression was commonly seen at ventral (deep) contacts, and programming settings resulting in tic suppression were commonly associated with a subjective feeling of calmness. This study provides safety and proof of concept that a scheduled DBS approach could improve motor and vocal tics in Tourette syndrome. Refinements in neurostimulator battery life, outcome measure selection, and flexibility in programming settings can be used to enhance outcomes in a future larger study. Scheduled stimulation holds promise as a potential first step for shifting movement and neuropsychiatric disorders toward more responsive neuromodulation approaches. clinicaltrials.gov Identifier: NCT01329198.

The contribution of psychological factors to recovery after mild traumatic brain injury: is cluster analysis a useful approach?

PubMed

Snell, Deborah L; Surgenor, Lois J; Hay-Smith, E Jean C; Williman, Jonathan; Siegert, Richard J

2015-01-01

Outcomes after mild traumatic brain injury (MTBI) vary, with slow or incomplete recovery for a significant minority. This study examines whether groups of cases with shared psychological factors but with different injury outcomes could be identified using cluster analysis. This is a prospective observational study following 147 adults presenting to a hospital-based emergency department or concussion services in Christchurch, New Zealand. This study examined associations between baseline demographic, clinical, psychological variables (distress, injury beliefs and symptom burden) and outcome 6 months later. A two-step approach to cluster analysis was applied (Ward's method to identify clusters, K-means to refine results). Three meaningful clusters emerged (high-adapters, medium-adapters, low-adapters). Baseline cluster-group membership was significantly associated with outcomes over time. High-adapters appeared recovered by 6-weeks and medium-adapters revealed improvements by 6-months. The low-adapters continued to endorse many symptoms, negative recovery expectations and distress, being significantly at risk for poor outcome more than 6-months after injury (OR (good outcome) = 0.12; CI = 0.03-0.53; p < 0.01). Cluster analysis supported the notion that groups could be identified early post-injury based on psychological factors, with group membership associated with differing outcomes over time. Implications for clinical care providers regarding therapy targets and cases that may benefit from different intensities of intervention are discussed.

Prosthetists' perceptions and use of outcome measures in clinical practice: Long-term effects of focused continuing education.

PubMed

Hafner, Brian J; Spaulding, Susan E; Salem, Rana; Morgan, Sara J; Gaunaurd, Ignacio; Gailey, Robert

2017-06-01

Continuing education is intended to facilitate clinicians' skills and knowledge in areas of practice, such as administration and interpretation of outcome measures. To evaluate the long-term effect of continuing education on prosthetists' confidence in administering outcome measures and their perceptions of outcomes measurement in clinical practice. Pretest-posttest survey methods. A total of 66 prosthetists were surveyed before, immediately after, and 2 years after outcomes measurement education and training. Prosthetists were grouped as routine or non-routine outcome measures users, based on experience reported prior to training. On average, prosthetists were just as confident administering measures 1-2 years after continuing education as they were immediately after continuing education. In all, 20% of prosthetists, initially classified as non-routine users, were subsequently classified as routine users at follow-up. Routine and non-routine users' opinions differed on whether outcome measures contributed to efficient patient evaluations (79.3% and 32.4%, respectively). Both routine and non-routine users reported challenges integrating outcome measures into normal clinical routines (20.7% and 45.9%, respectively). Continuing education had a long-term impact on prosthetists' confidence in administering outcome measures and may influence their clinical practices. However, remaining barriers to using standardized measures need to be addressed to keep practitioners current with evolving practice expectations. Clinical relevance Continuing education (CE) had a significant long-term impact on prosthetists' confidence in administering outcome measures and influenced their clinical practices. In all, approximately 20% of prosthetists, who previously were non-routine outcome measure users, became routine users after CE. There remains a need to develop strategies to integrate outcome measurement into routine clinical practice.

Antenatal Maternity Leave and Childbirth Using the First Baby Study: A Propensity Score Analysis.

PubMed

Goodman, Julia M; Guendelman, Sylvia; Kjerulff, Kristen H

Most employed American women work during pregnancy and continue working through the month they deliver. Yet, few studies estimate the relationship between maternity leave taken during pregnancy and maternal health. We evaluate the association of antenatal leave (ANL) uptake with obstetric outcomes, assessing the potential role of protective and adverse selection pathways on this relationship. We sample 1,740 employed women who delivered at term from the First Baby Study, a prospective cohort of nulliparous women in Pennsylvania. We use propensity scores to estimate the relationship between ANL and negative delivery outcomes (labor induction, long labor duration, unplanned cesarean delivery, and self-reported negative birth experience). We estimated propensity scores using a range of employment, health, and sociodemographic variables. One-half of the sampled women worked until the day before or day of delivery. Women who stopped working at least 2 days before delivery experienced 16% more negative delivery outcomes, on average, than women who worked until delivery, driven largely by a 25% higher predicted probability of unplanned cesarean section deliveries. These robust findings hold up to a range of sensitivity analyses and demonstrate selective mechanisms operating in ANL uptake. Our findings suggest that, even after controlling for an extensive set of observable employment, health, and sociodemographic characteristics, women who take ANL continue to differ in unobserved characteristics that lead to negative delivery outcomes. Like most U.S. states, Pennsylvania does not grant paid maternity leave. In a context of limited maternity leave availability, only relatively unhealthy women take ANL. Copyright © 2016 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Outcomes in Patients With Hemophilia and von Willebrand Disease Undergoing Invasive or Surgical Procedures.

PubMed

Chapin, John; Bamme, Jaqueline; Hsu, Fraustina; Christos, Paul; DeSancho, Maria

2017-03-01

Adults with hemophilia A (HA), hemophilia B (HB), and von Willebrand disease (VWD) frequently require surgery and invasive procedures. However, there is variability in perioperative management guidelines. We describe our periprocedural outcomes in this setting. A retrospective chart review from January 2006 to December 2012 of patients with HA, HB, and VWD undergoing surgery or invasive procedures was conducted. Type of procedures, management including the use of continuous factor infusion, and administration of antifibrinolytics were reviewed. Adverse outcomes were defined as acute bleeding (<48 hours), delayed bleeding (≥48 hours), transfusion, inhibitor development, and thrombosis. We identified 59 patients with HA and HB. In all, 24 patients had severe hemophilia and 12 had mild/moderate hemophilia. Twelve patients had inhibitors. There were also 5 female carriers of HA and 6 patients with VWD. There were 34 major surgeries (26 orthopedic, 8 nonorthopedic) and 129 minor surgeries. Continuous infusion was used in 55.9% of major surgeries versus 8.5% of minor surgeries. Antifibrinolytics were administered in 14.7% of major surgeries versus 23.2% of minor surgeries. In all, 4 patients developed acute bleeding and 10 patients developed delayed bleeding. Delayed bleeding occurred in 28.6% of genitourinary procedures and in 16.1% of dental procedures. Five patients acquired an inhibitor and 2 had thrombosis. In conclusion, patients with HA, HB, or VWD had similar rates of adverse outcomes when undergoing minor surgeries or major surgeries. This finding underscores the importance of an interdisciplinary management and procedure-specific guidelines for patients with hemophilia and VWD prior to even minor invasive procedures.

Exemplary Care and Learning Sites: A Model for Achieving Continual Improvement in Care and Learning in the Clinical Setting

PubMed Central

Ogrinc, Greg; Hoffman, Kimberly G.; Stevenson, Katherine M.; Shalaby, Marc; Beard, Albertine S.; Thörne, Karin E.; Coleman, Mary T.; Baum, Karyn D.

2016-01-01

Problem Current models of health care quality improvement do not explicitly describe the role of health professions education. The authors propose the Exemplary Care and Learning Site (ECLS) model as an approach to achieving continual improvement in care and learning in the clinical setting. Approach From 2008–2012, an iterative, interactive process was used to develop the ECLS model and its core elements—patients and families informing process changes; trainees engaging both in care and the improvement of care; leaders knowing, valuing, and practicing improvement; data transforming into useful information; and health professionals competently engaging both in care improvement and teaching about care improvement. In 2012–2013, a three-part feasibility test of the model, including a site self-assessment, an independent review of each site’s ratings, and implementation case stories, was conducted at six clinical teaching sites (in the United States and Sweden). Outcomes Site leaders reported the ECLS model provided a systematic approach toward improving patient (and population) outcomes, system performance, and professional development. Most sites found it challenging to incorporate the patients and families element. The trainee element was strong at four sites. The leadership and data elements were self-assessed as the most fully developed. The health professionals element exhibited the greatest variability across sites. Next Steps The next test of the model should be prospective, linked to clinical and educa tional outcomes, to evaluate whether it helps care delivery teams, educators, and patients and families take action to achieve better patient (and population) outcomes, system performance, and professional development. PMID:26760058

Coping and back problems: analysis of multiple data sources on an entire cross-sectional cohort of Swedish military recruits.

PubMed

Leboeuf-Yde, Charlotte; Larsen, Kristian; Ahlstrand, Ingvar; Volinn, Ernest

2006-05-03

As the literature now stands, a bewildering number and variety of biological, psychological and social factors are, apparently, implicated in back problems. However, if and how these have a direct influence on back problems is not clear. Obesity, for example, has in many studies been shown to be associated with back problems but there is no evidence for a causal link. This could be explained by a dearth of suitably designed studies but also because obesity may be but a proxy for some other, truly explanatory variable. Coping has been linked with, particularly, persistent back problems as well as with health in general. The question is, whether coping could be the explanatory link between, for example, these two variables. A cross-sectional study was undertaken using data from the Swedish Army, consisting of the entire cohort of males (N = 48,502) summoned in 1998 to serve in the military. The purpose of the study was to investigate the relation between five independent variables and two dependent variables ("outcome variables"). The independent variables were two anthropomorphic variables (height and body mass index), two psychological variables (intellectual capacity and coping in relation to stress), and one social variable (type of education). The two outcome variables were back problems and ill health. In particular, we wanted to determine whether controlling for coping would affect the associations between the other four independent variables and the two outcome variables. Data for the analysis come from a battery of standardized examinations, including medical examinations, a test of intellectual capacity, and a test of coping in relation to stress. Each of these examinations was conducted independently of the others. Unadjusted and adjusted odds ratios were calculated for the outcome variables of back problems and ill health. The associations between height, body mass index, intellectual capacity, type of education and the two outcome variables (back problems and ill health) were weak to moderate. Additionally, there were strong associations between coping and the two outcome variables and when controlling for coping the previously noted associations diminished or disappeared, whereas none of the other variables had a large effect on the association between coping and the two outcome variables. Coping emerged as strongly associated with both back problem and ill health and coping had a leveling effect on the associations between the other independent variables and the two outcome variables. This study is noteworthy particularly because the association with coping is so robust. It is a retrospective, cross-sectional study, however, and, as such it raises questions of causality; which - if any - came first, inability to cope or back pain? The results of this study call attention to the need for a prospective study, in which coping is clearly defined. Such a study has been undertaken and will be presented separately. Index terms: back pain, coping, education, height, BMI, intellectual capacity, bio-psycho-social model, epidemiology, cohort, cross-sectional study.

Vocational rehabilitation case manager factors associated with vocational rehabilitation service program outcomes for people with disabilities in Taiwan - an exploratory study.

PubMed

Wang, Yun-Tung; Lin, Yi-Jiun

2017-02-01

Purpose The aim of this study is to explore whether/which vocational rehabilitation case manager (VRCMer) factors were significantly associated with the vocational rehabilitation service (VRS) program outcomes in Taiwan. Method This study used the 2011 VRS Program for People with Disabilities Database in a metropolitan city in Taiwan (N = 466) to do a secondary data analysis using hierarchical logistic regression. Results This study found that the employment rate and stable employment rate created by the 2011 VRS program in a metropolitan city in Taiwan were 48.7% and 42.1%, respectively. For the predictors of employment/stable employment, "occurrences of the services provided by the VRCMer" variable was definitely dominant. In addition, "level of the disability" was the second-ranking predictor, and was significantly negatively correlated with both employment and stable employment outcomes. Conclusions Vocational rehabilitation case manager factors in this study were significantly correlated with VRS program outcomes for people with disabilities in Taiwan after controlling for the clients' socio-demographic variables. The results indicate that greater input by VRCMers for people with disabilities equates to better employment outcomes in metropolitan Taiwan. Implications for Rehabilitation This is the first study to build an inferential statistical model in attempt to explain and predict the association between vocational rehabilitation case manager factors and vocational rehabilitation service program outcomes for people with disabilities in Taiwan. In cases of severe disability, a vocational rehabilitation case manager should seek out more in-kind and in-cash resources, and choose a suitable job coach to cooperate in assisting the client to become employed. Based on the findings, government has to continue implementing opportunities for people with disabilities to attain higher and better quality educational levels, for increasing their employment rate. Vocational rehabilitation case managers should raise the referral rate and cooperation with job coaches as this directly affects the quality of services and clients' employment rate.

A review of covariate selection for non-experimental comparative effectiveness research.

PubMed

Sauer, Brian C; Brookhart, M Alan; Roy, Jason; VanderWeele, Tyler

2013-11-01

This paper addresses strategies for selecting variables for adjustment in non-experimental comparative effectiveness research and uses causal graphs to illustrate the causal network that relates treatment to outcome. Variables in the causal network take on multiple structural forms. Adjustment for a common cause pathway between treatment and outcome can remove confounding, whereas adjustment for other structural types may increase bias. For this reason, variable selection would ideally be based on an understanding of the causal network; however, the true causal network is rarely known. Therefore, we describe more practical variable selection approaches based on background knowledge when the causal structure is only partially known. These approaches include adjustment for all observed pretreatment variables thought to have some connection to the outcome, all known risk factors for the outcome, and all direct causes of the treatment or the outcome. Empirical approaches, such as forward and backward selection and automatic high-dimensional proxy adjustment, are also discussed. As there is a continuum between knowing and not knowing the causal, structural relations of variables, we recommend addressing variable selection in a practical way that involves a combination of background knowledge and empirical selection and that uses high-dimensional approaches. This empirical approach can be used to select from a set of a priori variables based on the researcher's knowledge to be included in the final analysis or to identify additional variables for consideration. This more limited use of empirically derived variables may reduce confounding while simultaneously reducing the risk of including variables that may increase bias. Copyright © 2013 John Wiley & Sons, Ltd.

A Review of Covariate Selection for Nonexperimental Comparative Effectiveness Research

PubMed Central

Sauer, Brian C.; Brookhart, Alan; Roy, Jason; Vanderweele, Tyler

2014-01-01

This paper addresses strategies for selecting variables for adjustment in non-experimental comparative effectiveness research (CER), and uses causal graphs to illustrate the causal network that relates treatment to outcome. Variables in the causal network take on multiple structural forms. Adjustment for on a common cause pathway between treatment and outcome can remove confounding, while adjustment for other structural types may increase bias. For this reason variable selection would ideally be based on an understanding of the causal network; however, the true causal network is rarely know. Therefore, we describe more practical variable selection approaches based on background knowledge when the causal structure is only partially known. These approaches include adjustment for all observed pretreatment variables thought to have some connection to the outcome, all known risk factors for the outcome, and all direct causes of the treatment or the outcome. Empirical approaches, such as forward and backward selection and automatic high-dimensional proxy adjustment, are also discussed. As there is a continuum between knowing and not knowing the causal, structural relations of variables, we recommend addressing variable selection in a practical way that involves a combination of background knowledge and empirical selection and that uses the high-dimensional approaches. This empirical approach can be used to select from a set of a priori variables based on the researcher’s knowledge to be included in the final analysis or to identify additional variables for consideration. This more limited use of empirically-derived variables may reduce confounding while simultaneously reducing the risk of including variables that may increase bias. PMID:24006330

Predicting the In-Hospital Responsiveness to Treatment of Alcoholics. Social Factors as Predictors of Outcome. Brain Damage as a Factor in Treatment Outcome of Chronic Alcoholic Patients.

ERIC Educational Resources Information Center

Mascia, George V.; And Others

The authors attempt to locate predictor variables associated with the outcome of alcoholic treatment programs. Muscia's study focuses on the predictive potential of: (1) response to a GSR conditioning procedure; (2) several personality variables; and (3) age and IQ measures. Nine variables, reflecting diverse perspectives, were selected as a basis…

Interim Report on Heuristics about Inspection Parameters: Updates to Heuristics Resulting from Refinement on Projects

NASA Technical Reports Server (NTRS)

Shull, Forrest; Seaman, Carolyn; Feldman, Raimund; Haingaertner, Ralf; Regardie, Myrna

2008-01-01

In 2008, we have continued analyzing the inspection data in an effort to better understand the applicability and effect of the inspection heuristics on inspection outcomes. Our research goals during this period are: 1. Investigate the effect of anomalies in the dataset (e.g. the very large meeting length values for some inspections) on our results 2. Investigate the effect of the heuristics on other inspection outcome variables (e.g. effort) 3. Investigate whether the recommended ranges can be modified to give inspection planners more flexibility without sacrificing effectiveness 4. Investigate possible refinements or modifications to the heuristics for specific subdomains (partitioned, e.g., by size, domain, or Center) This memo reports our results to date towards addressing these goals. In the next section, the first goal is addressed by describing the types of anomalies we have found in our dataset, how we have addressed them, and the effect of these changes on our previously reported results. In the following section, on "methodology", we describe the analyses we have conducted to address the other three goals and the results of these analyses are described in the "results" section. Finally, we conclude with future plans for continuing our investigation.

Family context and externalizing correlates of childhood animal cruelty in adjudicated delinquents.

PubMed

Walters, Glenn D; Noon, Alexandria

2015-05-01

The purpose of this study was to determine whether childhood animal cruelty is primarily a feature of family context or of externalizing behavior. Twenty measures of family context and proactive (fearlessness) and reactive (disinhibition) externalizing behavior were correlated with the retrospective accounts of childhood animal cruelty provided by 1,354 adjudicated delinquents. A cross-sectional analysis revealed that all 20 family context, proactive externalizing, and reactive externalizing variables correlated significantly with animal cruelty. Prospective analyses showed that when the animal cruelty variable was included in a regression equation with the 10 family context variables (parental arguing and fighting, parental drug use, parental hostility, and parental knowledge and monitoring of offspring behavior) or in a regression equation with the five reactive externalizing variables (interpersonal hostility, secondary psychopathy, weak impulse control, weak suppression of aggression, and short time horizon), it continued to predict future violent and income (property + drug) offending. The animal cruelty variable no longer predicted offending, however, when included in a regression equation with the five proactive externalizing variables (early onset behavioral problems, primary psychopathy, moral disengagement, positive outcome expectancies for crime, and lack of consideration for others). These findings suggest that while animal cruelty correlates with a wide range of family context and externalizing variables, it may serve as a marker of violent and nonviolent offending by virtue of its position on the proactive subdimension of the externalizing spectrum. © The Author(s) 2014.

Continuous Pre-Hospital Data as a Predictor of Outcome Following Major Trauma: A Study Using Improved and Expanded Data, Phase 2

DTIC Science & Technology

2010-03-01

and the data m anagement proce sses and procedures practiced by the SA EMS system were evolving, with changes and im provements in both variables...but limited) new monitor configuration and SA EMS processes a nd procedures adapted to the features of the new monitor. The first of the three... procedures for both the new m onitor and the S A EMS system over the upcom ing year. The two remaining data co llection inte rvals planned f or Phase 2 w ere

Efficiency of coherent-state quantum cryptography in the presence of loss: Influence of realistic error correction

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

Heid, Matthias; Luetkenhaus, Norbert

2006-05-15

We investigate the performance of a continuous-variable quantum key distribution scheme in a practical setting. More specifically, we take a nonideal error reconciliation procedure into account. The quantum channel connecting the two honest parties is assumed to be lossy but noiseless. Secret key rates are given for the case that the measurement outcomes are postselected or a reverse reconciliation scheme is applied. The reverse reconciliation scheme loses its initial advantage in the practical setting. If one combines postselection with reverse reconciliation, however, much of this advantage can be recovered.

Effect of continued treatment with pirfenidone following clinically meaningful declines in forced vital capacity: analysis of data from three phase 3 trials in patients with idiopathic pulmonary fibrosis.

PubMed

Nathan, Steven D; Albera, Carlo; Bradford, Williamson Z; Costabel, Ulrich; du Bois, Roland M; Fagan, Elizabeth A; Fishman, Robert S; Glaspole, Ian; Glassberg, Marilyn K; Glasscock, Kenneth F; King, Talmadge E; Lancaster, Lisa; Lederer, David J; Lin, Zhengning; Pereira, Carlos A; Swigris, Jeffrey J; Valeyre, Dominique; Noble, Paul W; Wells, Athol U

2016-05-01

The assessment of treatment response in idiopathic pulmonary fibrosis (IPF) is complicated by the variable clinical course. We examined the variability in the rate of disease progression and evaluated the effect of continued treatment with pirfenidone in patients who experienced meaningful progression during treatment. The source population included patients enrolled in the ASCEND and CAPACITY trials (N=1247). Pearson's correlation coefficients were used to characterise the relationship between changes in FVC during consecutive 6-month intervals in the placebo population. Outcomes following a ≥10% decline in FVC were evaluated by comparing the proportion of patients in the pirfenidone and placebo groups who experienced a ≥10% decline in FVC or death during the subsequent 6 months. A weak negative correlation was observed between FVC changes during consecutive intervals in the placebo population (coefficient, -0.146, p<0.001), indicating substantial variability. Thirty-four (5.5%) and 68 (10.9%) patients in the pirfenidone and placebo groups, respectively, experienced a ≥10% decline in FVC by month 6. During the subsequent 6 months, fewer patients in the pirfenidone group compared with placebo experienced a ≥10% decline in FVC or death (5.9% vs 27.9%; relative difference, 78.9%). There was one (2.9%) death in the pirfenidone group and 14 (20.6%) deaths in the placebo group (relative difference, 85.7%). Longitudinal FVC data from patients with IPF showed substantial intrasubject variability, underscoring the inability to reliably assess therapeutic response using serial FVC trends. In patients who progressed during treatment, continued treatment with pirfenidone resulted in a lower risk of subsequent FVC decline or death. NCT01366209, NCT00287729, NCT00287716. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Effect of continued treatment with pirfenidone following clinically meaningful declines in forced vital capacity: analysis of data from three phase 3 trials in patients with idiopathic pulmonary fibrosis

PubMed Central

Nathan, Steven D; Albera, Carlo; Bradford, Williamson Z; Costabel, Ulrich; du Bois, Roland M; Fagan, Elizabeth A; Fishman, Robert S; Glaspole, Ian; Glassberg, Marilyn K; King, Talmadge E; Lancaster, Lisa; Lederer, David J; Lin, Zhengning; Pereira, Carlos A; Swigris, Jeffrey J; Valeyre, Dominique; Noble, Paul W; Wells, Athol U

2016-01-01

Background The assessment of treatment response in idiopathic pulmonary fibrosis (IPF) is complicated by the variable clinical course. We examined the variability in the rate of disease progression and evaluated the effect of continued treatment with pirfenidone in patients who experienced meaningful progression during treatment. Methods The source population included patients enrolled in the ASCEND and CAPACITY trials (N=1247). Pearson's correlation coefficients were used to characterise the relationship between changes in FVC during consecutive 6-month intervals in the placebo population. Outcomes following a ≥10% decline in FVC were evaluated by comparing the proportion of patients in the pirfenidone and placebo groups who experienced a ≥10% decline in FVC or death during the subsequent 6 months. Results A weak negative correlation was observed between FVC changes during consecutive intervals in the placebo population (coefficient, −0.146, p<0.001), indicating substantial variability. Thirty-four (5.5%) and 68 (10.9%) patients in the pirfenidone and placebo groups, respectively, experienced a ≥10% decline in FVC by month 6. During the subsequent 6 months, fewer patients in the pirfenidone group compared with placebo experienced a ≥10% decline in FVC or death (5.9% vs 27.9%; relative difference, 78.9%). There was one (2.9%) death in the pirfenidone group and 14 (20.6%) deaths in the placebo group (relative difference, 85.7%). Conclusions Longitudinal FVC data from patients with IPF showed substantial intrasubject variability, underscoring the inability to reliably assess therapeutic response using serial FVC trends. In patients who progressed during treatment, continued treatment with pirfenidone resulted in a lower risk of subsequent FVC decline or death. Trial registration numbers NCT01366209, NCT00287729, NCT00287716. PMID:26968970

Size and consistency of problem-solving consultation outcomes: an empirical analysis.

PubMed

Hurwitz, Jason T; Kratochwill, Thomas R; Serlin, Ronald C

2015-04-01

In this study, we analyzed extant data to evaluate the variability and magnitude of students' behavior change outcomes (academic, social, and behavioral) produced by consultants through problem-solving consultation with teachers. Research questions were twofold: (a) Do consultants produce consistent and sizeable positive student outcomes across their cases as measured through direct and frequent assessment? and (b) What proportion of variability in student outcomes is attributable to consultants? Analyses of extant data collected from problem-solving consultation outcome studies that used single-case, time-series AB designs with multiple participants were analyzed. Four such studies ultimately met the inclusion criteria for the extant data, comprising 124 consultants who worked with 302 school teachers regarding 453 individual students. Consultants constituted the independent variable, while the primary dependent variable was a descriptive effect size based on student behavior change as measured by (a) curriculum-based measures, (b) permanent products, or (c) direct observations. Primary analyses involved visual and statistical evaluation of effect size magnitude and variability observed within and between consultants and studies. Given the nested nature of the data, multilevel analyses were used to assess consultant effects on student outcomes. Results suggest that consultants consistently produced positive effect sizes on average across their cases, but outcomes varied between consultants. Findings also indicated that consultants, teachers, and the corresponding studies accounted for a significant proportion of variability in student outcomes. This investigation advances the use of multilevel and integrative data analyses to evaluate consultation outcomes and extends research on problem-solving consultation, consultant effects, and meta-analysis of case study AB designs. Practical implications for evaluating consultation service delivery in school settings are also discussed. Copyright © 2015 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Enhancement of the security of a practical continuous-variable quantum-key-distribution system by manipulating the intensity of the local oscillator

NASA Astrophysics Data System (ADS)

Ma, Xiang-Chun; Sun, Shi-Hai; Jiang, Mu-Sheng; Gui, Ming; Zhou, Yan-Li; Liang, Lin-Mei

2014-03-01

In a practical continuous-variable quantum-key distribution (CVQKD), the fluctuations of the local oscillator (LO) not only make the normalization of Bob's measurement outcomes difficult, but also can change the signal-to-noise ratio (SNR) of an imperfect balanced homodyne detector (BHD), which may lead the security of a practical system of CVQKD to be compromised severely. In this paper, we propose that the LO intensity can be manipulated by the legitimate parties, i.e., being tuned and stabilized to a required constant value, to eliminate the impact of LO fluctuations and defeat Eve's potential attack on the LO. Moreover, we show that the secret key rate can be increased over a noisy channel, especially the channels of metropolitan QKD networks, by tuning the intensity of LO and thus the SNR of a practical BHD to an optimal value, and we find that, counterintuitively, the requirement on BHD (i.e., high detection efficiency and low electronic noise) can also be reduced in this case. To realize this manipulation, we give a schematic setup which, thus, can be used to enhance the security of a practical CVQKD system.

cit: hypothesis testing software for mediation analysis in genomic applications.

PubMed

Millstein, Joshua; Chen, Gary K; Breton, Carrie V

2016-08-01

The challenges of successfully applying causal inference methods include: (i) satisfying underlying assumptions, (ii) limitations in data/models accommodated by the software and (iii) low power of common multiple testing approaches. The causal inference test (CIT) is based on hypothesis testing rather than estimation, allowing the testable assumptions to be evaluated in the determination of statistical significance. A user-friendly software package provides P-values and optionally permutation-based FDR estimates (q-values) for potential mediators. It can handle single and multiple binary and continuous instrumental variables, binary or continuous outcome variables and adjustment covariates. Also, the permutation-based FDR option provides a non-parametric implementation. Simulation studies demonstrate the validity of the cit package and show a substantial advantage of permutation-based FDR over other common multiple testing strategies. The cit open-source R package is freely available from the CRAN website (https://cran.r-project.org/web/packages/cit/index.html) with embedded C ++ code that utilizes the GNU Scientific Library, also freely available (http://www.gnu.org/software/gsl/). joshua.millstein@usc.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Intercenter Differences in Bronchopulmonary Dysplasia or Death Among Very Low Birth Weight Infants

PubMed Central

Walsh, Michele; Bobashev, Georgiy; Das, Abhik; Levine, Burton; Carlo, Waldemar A.; Higgins, Rosemary D.

2011-01-01

OBJECTIVES: To determine (1) the magnitude of clustering of bronchopulmonary dysplasia (36 weeks) or death (the outcome) across centers of the Eunice Kennedy Shriver National Institute of Child and Human Development National Research Network, (2) the infant-level variables associated with the outcome and estimate their clustering, and (3) the center-specific practices associated with the differences and build predictive models. METHODS: Data on neonates with a birth weight of <1250 g from the cluster-randomized benchmarking trial were used to determine the magnitude of clustering of the outcome according to alternating logistic regression by using pairwise odds ratio and predictive modeling. Clinical variables associated with the outcome were identified by using multivariate analysis. The magnitude of clustering was then evaluated after correction for infant-level variables. Predictive models were developed by using center-specific and infant-level variables for data from 2001 2004 and projected to 2006. RESULTS: In 2001–2004, clustering of bronchopulmonary dysplasia/death was significant (pairwise odds ratio: 1.3; P < .001) and increased in 2006 (pairwise odds ratio: 1.6; overall incidence: 52%; range across centers: 32%–74%); center rates were relatively stable over time. Variables that varied according to center and were associated with increased risk of outcome included lower body temperature at NICU admission, use of prophylactic indomethacin, specific drug therapy on day 1, and lack of endotracheal intubation. Center differences remained significant even after correction for clustered variables. CONCLUSION: Bronchopulmonary dysplasia/death rates demonstrated moderate clustering according to center. Clinical variables associated with the outcome were also clustered. Center differences after correction of clustered variables indicate presence of as-yet unmeasured center variables. PMID:21149431

Mutilating Data and Discarding Variance: The Dangers of Dichotomizing Continuous Variables.

ERIC Educational Resources Information Center

Kroff, Michael W.

This paper reviews issues involved in converting continuous variables to nominal variables to be used in the OVA techniques. The literature dealing with the dangers of dichotomizing continuous variables is reviewed. First, the assumptions invoked by OVA analyses are reviewed in addition to concerns regarding the loss of variance and a reduction in…

Evaluating choices by single neurons in the frontal lobe: outcome value encoded across multiple decision variables

PubMed Central

Kennerley, Steven W.; Wallis, Jonathan D.

2009-01-01

Damage to the frontal lobe can cause severe decision-making impairments. A mechanism that may underlie this is that neurons in the frontal cortex encode many variables that contribute to the valuation of a choice, such as its costs, benefits and probability of success. However, optimal decision-making requires that one considers these variables, not only when faced with the choice, but also when evaluating the outcome of the choice, in order to adapt future behaviour appropriately. To examine the role of the frontal cortex in encoding the value of different choice outcomes, we simultaneously recorded the activity of multiple single neurons in the anterior cingulate cortex (ACC), orbitofrontal cortex (OFC) and lateral prefrontal cortex (LPFC) while subjects evaluated the outcome of choices involving manipulations of probability, payoff and cost. Frontal neurons encoded many of the parameters that enabled the calculation of the value of these variables, including the onset and offset of reward and the amount of work performed, and often encoded the value of outcomes across multiple decision variables. In addition, many neurons encoded both the predicted outcome during the choice phase of the task as well as the experienced outcome in the outcome phase of the task. These patterns of selectivity were more prevalent in ACC relative to OFC and LPFC. These results support a role for the frontal cortex, principally ACC, in selecting between choice alternatives and evaluating the outcome of that selection thereby ensuring that choices are optimal and adaptive. PMID:19453638

Statistical grand rounds: understanding the mechanism: mediation analysis in randomized and nonrandomized studies.

PubMed

Mascha, Edward J; Dalton, Jarrod E; Kurz, Andrea; Saager, Leif

2013-10-01

In comparative clinical studies, a common goal is to assess whether an exposure, or intervention, affects the outcome of interest. However, just as important is to understand the mechanism(s) for how the intervention affects outcome. For example, if preoperative anemia was shown to increase the risk of postoperative complications by 15%, it would be important to quantify how much of that effect was due to patients receiving intraoperative transfusions. Mediation analysis attempts to quantify how much, if any, of the effect of an intervention on outcome goes though prespecified mediator, or "mechanism" variable(s), that is, variables sitting on the causal pathway between exposure and outcome. Effects of an exposure on outcome can thus be divided into direct and indirect, or mediated, effects. Mediation is claimed when 2 conditions are true: the exposure affects the mediator and the mediator (adjusting for the exposure) affects the outcome. Understanding how an intervention affects outcome can validate or invalidate one's original hypothesis and also facilitate further research to modify the responsible factors, and thus improve patient outcome. We discuss the proper design and analysis of studies investigating mediation, including the importance of distinguishing mediator variables from confounding variables, the challenge of identifying potential mediators when the exposure is chronic versus acute, and the requirements for claiming mediation. Simple designs are considered, as well as those containing multiple mediators, multiple outcomes, and mixed data types. Methods are illustrated with data collected by the National Surgical Quality Improvement Project (NSQIP) and utilized in a companion paper which assessed the effects of preoperative anemic status on postoperative outcomes.

Relationship of pharmaceutical promotion to antidepressant switching and adherence: a retrospective cohort study.

PubMed

Hansen, Richard A; Chen, Shih-Yin; Gaynes, Bradley N; Maciejewski, Matthew L

2010-12-01

Patient nonadherence and early discontinuation of antidepressant treatment are common. Pharmaceutical promotion to consumers and physicians may influence this behavior. The objectives of this study were to explore whether promotional spending is related to early antidepressant switching, acute-phase adherence, and continuation-phase adherence. A retrospective cohort study was conducted with national promotional expenditure data merged with medical and prescription claims data from a large national health plan affiliated with i3 Innovus. Included were records for continuously insured adults with major depression who received a new prescription for an antidepressant: 5,010 were in the cohort assessed for switching, 4,457 were in the cohort assessed for acute-phase adherence, and 1,772 were in the cohort assessed for continuation-phase adherence. National promotional efforts were estimated by examining inflation-adjusted spending on direct-to-consumer advertising (DTCA) and physician detailing. Clinical guidelines were used to create proxies for aspects of treatment outcomes, including antidepressant switching and adherence in the acute phase and adherence in the continuation phase. Logistic regression models estimated the association between promotional variables and these outcomes. Patients taking medications that were more highly promoted to physicians were less likely to switch medications (odds ratio [OR]=.61) and were more likely to be adherent during the acute phase of treatment (OR=1.13). DTCA had little effect on switching or antidepressant adherence. Detailing to physicians was associated with lower rates of medication switching and had a positive relationship with patient adherence during early antidepressant treatment. This finding indicates that certain aspects of promotion may have beneficial effects on antidepressant use.

Simulation and qualitative analysis of glucose variability, mean glucose, and hypoglycemia after subcutaneous insulin therapy for stress hyperglycemia.

PubMed

Strilka, Richard J; Stull, Mamie C; Clemens, Michael S; McCaver, Stewart C; Armen, Scott B

2016-01-27

The critically ill can have persistent dysglycemia during the "subacute" recovery phase of their illness because of altered gene expression; it is also not uncommon for these patients to receive continuous enteral nutrition during this time. The optimal short-acting subcutaneous insulin therapy that should be used in this clinical scenario, however, is unknown. Our aim was to conduct a qualitative numerical study of the glucose-insulin dynamics within this patient population to answer the above question. This analysis may help clinicians design a relevant clinical trial. Eight virtual patients with stress hyperglycemia were simulated by means of a mathematical model. Each virtual patient had a different combination of insulin resistance and insulin deficiency that defined their unique stress hyperglycemia state; the rate of gluconeogenesis was also doubled. The patients received 25 injections of subcutaneous regular or Lispro insulin (0-6 U) with 3 rates of continuous nutrition. The main outcome measurements were the change in mean glucose concentration, the change in glucose variability, and hypoglycemic episodes. These end points were interpreted by how the ultradian oscillations of glucose concentration were affected by each insulin preparation. Subcutaneous regular insulin lowered both mean glucose concentrations and glucose variability in a linear fashion. No hypoglycemic episodes were noted. Although subcutaneous Lispro insulin lowered mean glucose concentrations, glucose variability increased in a nonlinear fashion. In patients with high insulin resistance and nutrition at goal, "rebound hyperglycemia" was noted after the insulin analog was rapidly metabolized. When the nutritional source was removed, hypoglycemia tended to occur at higher Lispro insulin doses. Finally, patients with severe insulin resistance seemed the most sensitive to insulin concentration changes. Subcutaneous regular insulin consistently lowered mean glucose concentrations and glucose variability; its linear dose-response curve rendered the preparation better suited for a sliding-scale protocol. The longer duration of action of subcutaneous regular insulin resulted in better glycemic-control metrics for patients who were continuously postprandial. Clinical trials are needed to examine whether these numerical results represent the glucose-insulin dynamics that occur in intensive care units; if present, their clinical effects should be evaluated.

Selection of latent variables for multiple mixed-outcome models

PubMed Central

ZHOU, LING; LIN, HUAZHEN; SONG, XINYUAN; LI, YI

2014-01-01

Latent variable models have been widely used for modeling the dependence structure of multiple outcomes data. However, the formulation of a latent variable model is often unknown a priori, the misspecification will distort the dependence structure and lead to unreliable model inference. Moreover, multiple outcomes with varying types present enormous analytical challenges. In this paper, we present a class of general latent variable models that can accommodate mixed types of outcomes. We propose a novel selection approach that simultaneously selects latent variables and estimates parameters. We show that the proposed estimator is consistent, asymptotically normal and has the oracle property. The practical utility of the methods is confirmed via simulations as well as an application to the analysis of the World Values Survey, a global research project that explores peoples’ values and beliefs and the social and personal characteristics that might influence them. PMID:27642219

Bias and Bias Correction in Multi-Site Instrumental Variables Analysis of Heterogeneous Mediator Effects

ERIC Educational Resources Information Center

Reardon, Sean F.; Unlu, Faith; Zhu, Pei; Bloom, Howard

2013-01-01

We explore the use of instrumental variables (IV) analysis with a multi-site randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, as assumption known in the instrumental variables literature as the…

Electroencephalography Predicts Poor and Good Outcomes After Cardiac Arrest: A Two-Center Study.

PubMed

Rossetti, Andrea O; Tovar Quiroga, Diego F; Juan, Elsa; Novy, Jan; White, Roger D; Ben-Hamouda, Nawfel; Britton, Jeffrey W; Oddo, Mauro; Rabinstein, Alejandro A

2017-07-01

The prognostic role of electroencephalography during and after targeted temperature management in postcardiac arrest patients, relatively to other predictors, is incompletely known. We assessed performances of electroencephalography during and after targeted temperature management toward good and poor outcomes, along with other recognized predictors. Cohort study (April 2009 to March 2016). Two academic hospitals (Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; Mayo Clinic, Rochester, MN). Consecutive comatose adults admitted after cardiac arrest, identified through prospective registries. All patients were managed with targeted temperature management, receiving prespecified standardized clinical, neurophysiologic (particularly, electroencephalography during and after targeted temperature management), and biochemical evaluations. We assessed electroencephalography variables (reactivity, continuity, epileptiform features, and prespecified "benign" or "highly malignant" patterns based on the American Clinical Neurophysiology Society nomenclature) and other clinical, neurophysiologic (somatosensory-evoked potential), and biochemical prognosticators. Good outcome (Cerebral Performance Categories 1 and 2) and mortality predictions at 3 months were calculated. Among 357 patients, early electroencephalography reactivity and continuity and flexor or better motor reaction had greater than 70% positive predictive value for good outcome; reactivity (80.4%; 95% CI, 75.9-84.4%) and motor response (80.1%; 95% CI, 75.6-84.1%) had highest accuracy. Early benign electroencephalography heralded good outcome in 86.2% (95% CI, 79.8-91.1%). False positive rates for mortality were less than 5% for epileptiform or nonreactive early electroencephalography, nonreactive late electroencephalography, absent somatosensory-evoked potential, absent pupillary or corneal reflexes, presence of myoclonus, and neuron-specific enolase greater than 75 µg/L; accuracy was highest for early electroencephalography reactivity (86.6%; 95% CI, 82.6-90.0). Early highly malignant electroencephalography had an false positive rate of 1.5% with accuracy of 85.7% (95% CI, 81.7-89.2%). This study provides class III evidence that electroencephalography reactivity predicts both poor and good outcomes, and motor reaction good outcome after cardiac arrest. Electroencephalography reactivity seems to be the best discriminator between good and poor outcomes. Standardized electroencephalography interpretation seems to predict both conditions during and after targeted temperature management.

Continuously-Variable Positive-Mesh Power Transmission

NASA Technical Reports Server (NTRS)

Johnson, J. L.

1982-01-01

Proposed transmission with continuously-variable speed ratio couples two mechanical trigonometric-function generators. Transmission is expected to handle higher loads than conventional variable-pulley drives; and, unlike variable pulley, positive traction through entire drive train with no reliance on friction to transmit power. Able to vary speed continuously through zero and into reverse. Possible applications in instrumentation where drive-train slippage cannot be tolerated.

Effect of progestin vs. combined oral contraceptive pills on lactation: A double-blind randomized controlled trial

PubMed Central

Espey, Eve; Ogburn, Tony; Leeman, Larry; Singh, Rameet; Schrader, Ronald

2013-01-01

Objective To estimate the effect of progestin-only vs. combined hormonal contraceptive pills on rates of breastfeeding continuation in postpartum women. Secondary outcomes include infant growth parameters, contraceptive method continuation and patient satisfaction with breastfeeding and contraceptive method. Methods In this randomized controlled trial, postpartum breastfeeding women who desired oral contraceptives were assigned to progestin-only vs. combined hormonal contraceptive pills. At two and eight weeks postpartum, participants completed in-person questionnaires that assessed breastfeeding continuation and contraceptive use. Infant growth parameters including weight, length and head circumference were assessed at eight weeks postpartum. Telephone questionnaires assessing breastfeeding, contraceptive continuation and satisfaction were completed at 3-7 weeks and 4 and 6 months. Breastfeeding continuation was compared between groups using Cox proportional hazards regression. Differences in baseline demographic characteristics and in variables between the two intervention groups were compared using chi-square tests, Fisher’s Exact test, or two-sample t-tests as appropriate. Results Breastfeeding continuation rates, contraceptive continuation, and infant growth parameters did not differ between users of progestin-only and combined hormonal contraceptive pills. Infant formula supplementation and maternal perception of inadequate milk supply were associated with decreased rates of breastfeeding in both groups. Conclusions Choice of combined or progestin-only birth control pills administered two weeks postpartum did not adversely affect breastfeeding continuation. PMID:22143258

Moderation and Mediation in Structural Equation Modeling: Applications for Early Intervention Research

ERIC Educational Resources Information Center

Hopwood, Christopher J.

2007-01-01

Second-generation early intervention research typically involves the specification of multivariate relations between interventions, outcomes, and other variables. Moderation and mediation involve variables or sets of variables that influence relations between interventions and outcomes. Following the framework of Baron and Kenny's (1986) seminal…

Collinearity and Causal Diagrams: A Lesson on the Importance of Model Specification.

PubMed

Schisterman, Enrique F; Perkins, Neil J; Mumford, Sunni L; Ahrens, Katherine A; Mitchell, Emily M

2017-01-01

Correlated data are ubiquitous in epidemiologic research, particularly in nutritional and environmental epidemiology where mixtures of factors are often studied. Our objectives are to demonstrate how highly correlated data arise in epidemiologic research and provide guidance, using a directed acyclic graph approach, on how to proceed analytically when faced with highly correlated data. We identified three fundamental structural scenarios in which high correlation between a given variable and the exposure can arise: intermediates, confounders, and colliders. For each of these scenarios, we evaluated the consequences of increasing correlation between the given variable and the exposure on the bias and variance for the total effect of the exposure on the outcome using unadjusted and adjusted models. We derived closed-form solutions for continuous outcomes using linear regression and empirically present our findings for binary outcomes using logistic regression. For models properly specified, total effect estimates remained unbiased even when there was almost perfect correlation between the exposure and a given intermediate, confounder, or collider. In general, as the correlation increased, the variance of the parameter estimate for the exposure in the adjusted models increased, while in the unadjusted models, the variance increased to a lesser extent or decreased. Our findings highlight the importance of considering the causal framework under study when specifying regression models. Strategies that do not take into consideration the causal structure may lead to biased effect estimation for the original question of interest, even under high correlation.

Neighborhood Social Cohesion and Sleep Outcomes in the Native Hawaiian and Pacific Islander National Health Interview Survey.

PubMed

Young, Marielle C; Gerber, Monica W; Ash, Tayla; Horan, Christine M; Taveras, Elsie M

2018-05-16

Native Hawaiians and Pacific Islanders (NHPIs) have the lowest attainment of healthy sleep duration among all racial and ethnic groups in the United States. We examined associations of neighborhood social cohesion with sleep duration and quality. Cross-sectional analysis of 2,464 adults in the NHPI National Health Interview Survey (2014). Neighborhood social cohesion was categorized as a continuous and categorical variable into low (<12), medium (12-14) and high (>15) according to tertiles of the distribution of responses. We used multinomial logistic regression to examine the adjusted odds ratio of short and long sleep duration relative to intermediate sleep duration. We used binary logistic regression for dichotomous sleep quality outcomes. Sleep outcomes were modeled as categorical variables. 40% of the cohort reported short (<7 hours) sleep duration and only 4% reported long (>9 hours) duration. Mean (SE, range) social cohesion score was 12.4 units (0.11, 4-16) and 23% reported low social cohesion. In multivariable models, each 1 SD decrease in neighborhood social cohesion score was associated with higher odds of short sleep duration (OR: 1.14, 95% CI: 1.02, 1.29). Additionally, low social cohesion was associated with increased odds of short sleep duration (OR: 1.53, 95% CI: 1.10, 2.13). No associations between neighborhood social cohesion and having trouble falling or staying asleep and feeling well rested were found. Low neighborhood social cohesion is associated with short sleep duration in NHPIs.

Continuous-variable controlled-Z gate using an atomic ensemble

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

Wang Mingfeng; Jiang Nianquan; Jin Qingli

2011-06-15

The continuous-variable controlled-Z gate is a canonical two-mode gate for universal continuous-variable quantum computation. It is considered as one of the most fundamental continuous-variable quantum gates. Here we present a scheme for realizing continuous-variable controlled-Z gate between two optical beams using an atomic ensemble. The gate is performed by simply sending the two beams propagating in two orthogonal directions twice through a spin-squeezed atomic medium. Its fidelity can run up to one if the input atomic state is infinitely squeezed. Considering the noise effects due to atomic decoherence and light losses, we show that the observed fidelities of the schememore » are still quite high within presently available techniques.« less

Determinants and predictors of outcome in super refractory status epilepticus--a developing country perspective.

PubMed

Jayalakshmi, Sita; Ruikar, Devashish; Vooturi, Sudhindra; Alladi, Suvarna; Sahu, Sambit; Kaul, Subhash; Mohandas, Surath

2014-11-01

Super refractory status epilepticus (SRSE) is a recent entity. There is limited information about the etiology and outcome of SRSE from developing countries. We evaluated determinants and predictors of outcome in patients with convulsive SRSE in Indian population. In this open cohort study, data of patients with convulsive SE admitted in neurointensive care unit (NICU) from 2005 to 2013 was retrospectively analyzed. Regression and survival analysis was done for outcome of patients divided into non refractory SE (NRSE), refractory SE (RSE), and SRSE groups. The primary outcome for analysis was in hospital mortality. Also functional outcome at 6 months was graded according to the Glasgow outcome scale (GOS), and classified as good (GOS 4 and 5) and poor (GOS 1, 2 and 3) outcome groups. Out of 177 patients with SE, 105 (59.3%) had NRSE; 72 (40.7%) had RSE of which 30 (16.9% of 177) were sub-classified as SRSE. SRSE was frequent (39%) in children (p<0.01), elderly (21.7%; p<0.003), and in incident SE (82.1%, p=0.05). Encephalitis was the commonest etiology in RSE (30.9%, p=0.015), SRSE (66.7%, p<0.001) than NRSE (12.3%). Encephalitis (β=8.250 (1.8-37.82); p=0.007) was the determinant of the progression of SE to SRSE. Overall mortality was 19.2%, highest in SRSE (40.0%) followed by RSE (35.7%), both significantly (p<0.001) higher than NRSE (6.7%). Mortality was high in patients with encephalitis than other etiologies (39.1% vs. 12.1%; p=0.001). Acidosis predicted mortality in the entire cohort (β=7.313 (1.6-32.58); p=0.009); however none of the variables predicted mortality in SRSE patients. At 6 months follow up only 33.3% of patients with SRSE were in GOS good outcome group when compared to RSE (33.3% vs. 57.1%; p=0.055), and NRSE (33.3% vs. 79.1%; p<0.0001). SRSE is common in children, elderly, and incident SE. Encephalitis was the determinant of progression of SE to SRSE. None of the variables predicted mortality in SRSE patients. Sixty percent of patients with SRSE survived and one third had good outcome. Therefore one should continue the care inspite of weeks of SE. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of early variables in traumatic brain injury on functional independence measure scores and rehabilitation length of stay and charges.

PubMed

Cowen, T D; Meythaler, J M; DeVivo, M J; Ivie, C S; Lebow, J; Novack, T A

1995-09-01

To determine the relationship between early variables (initial Glasgow Coma Scale [GCS] scores, computed tomography [CT] findings, presence of skeletal trauma, age, length of acute hospitalization) and outcome variables (Functional Independence Measure [FIM] scores, rehabilitation length of stay [LOS], rehabilitation charges) in traumatic brain injury (TBI). Inception cohort. University tertiary care rehabilitation center. 91 patients with TBI. Inpatient rehabilitation. FIM, rehabilitation LOS, and rehabilitation charges. Patients in the severely impaired (GCS = 3 to 7) group showed significantly lower (p = .01) mean admission and discharge motor scores (21.26, 39.83) than patients in the mildly impaired (GCS = 13 to 15) group (38.86, 55.29). Cognitive scores were also significantly lower (p < .01) in the severely impaired group on admission (26.73 vs 54.14) and discharge (42.28 vs 66.48). These findings continued to be statistically significant (p < .01) after regression analysis accounted for the other early variables previously listed. Regression analysis also illustrated that longer acute hospitalization LOS was independently associated with significantly lower admission motor (p < .01) and cognitive (p = .05) scores, and significantly higher (p = .01) rehabilitation charges. Patients with CT findings of intracranial bleed with skull fracture had longer total LOS (70.88 vs 43.08 days; p < .05), rehabilitation LOS (30.01 vs 19.68 days; p < .10), and higher rehabilitation charges ($43,346 vs $25,780; p < .05). Paradoxically, those patients in a motor vehicle crash with an extremity bone fracture had significantly higher (p = .002; p = .04 after regression analysis) FIM cognitive scores on admission (48.30 vs 27.28) and discharge (64.74 vs 45.78) than those without a fracture. Finally, data available on rehabilitation admission were used to predict discharge outcomes. The percentage of explained variance for each outcome variable is as follows: discharge FIM motor score, 69.5%; discharge FIM cognitive score, 71.2%; rehabilitation LOS, 54.1%; rehabilitation charges, 61.1%. The most powerful predictor of LOS and charges was the admission FIM motor score (p < .001), followed by CT findings (p = .02) and age (p = .04). Information readily available on rehabilitation admission, particularly the FIM motor score, may be useful in predicting discharge FIM scores as well as utilization of medical rehabilitation resources. Earlier transfer to rehabilitation may result in higher functional status and lower rehabilitation charges, as well as lower acute hospitalization charges. The presence of extremity fractures encountered during a motor vehicle crash is associated with a more favorable outcome in TBI as evidenced by higher discharge FIM cognitive scores.

Systems approach to managing educational quality in the engineering classroom

NASA Astrophysics Data System (ADS)

Grygoryev, Kostyantyn

Today's competitive environment in post-secondary education requires universities to demonstrate the quality of their programs in order to attract financing, and student and academic talent. Despite significant efforts devoted to improving the quality of higher education, systematic, continuous performance measurement and management still have not reached the level where educational outputs and outcomes are actually produced---the classroom. An engineering classroom is a complex environment in which educational inputs are transformed by educational processes into educational outputs and outcomes. By treating a classroom as a system, one can apply tools such as Structural Equation Modeling, Statistical Process Control, and System Dynamics in order to discover cause-and-effect relationships among the classroom variables, control the classroom processes, and evaluate the effect of changes to the course organization, content, and delivery, on educational processes and outcomes. Quality improvement is best achieved through the continuous, systematic application of efforts and resources. Improving classroom processes and outcomes is an iterative process that starts with identifying opportunities for improvement, designing the action plan, implementing the changes, and evaluating their effects. Once the desired objectives are achieved, the quality improvement cycle may start again. The goal of this research was to improve the educational processes and outcomes in an undergraduate engineering management course taught at the University of Alberta. The author was involved with the course, first, as a teaching assistant, and, then, as a primary instructor. The data collected from the course over four years were used to create, first, a static and, then, a dynamic model of a classroom system. By using model output and qualitative feedback from students, changes to the course organization and content were introduced. These changes led to a lower perceived course workload and increased the students' satisfaction with the instructor, but the students' overall satisfaction with the course did not change significantly, and their attitude toward the course subject actually became more negative. This research brought performance measurement to the level of a classroom, created a dynamic model of the classroom system based on the cause-and-effect relationships discovered by using statistical analysis, and used a systematic, continuous improvement approach to modify the course in order to improve selected educational processes and outcomes.

Capacity shortfalls hinder the performance of marine protected areas globally

NASA Astrophysics Data System (ADS)

Gill, David A.; Mascia, Michael B.; Ahmadia, Gabby N.; Glew, Louise; Lester, Sarah E.; Barnes, Megan; Craigie, Ian; Darling, Emily S.; Free, Christopher M.; Geldmann, Jonas; Holst, Susie; Jensen, Olaf P.; White, Alan T.; Basurto, Xavier; Coad, Lauren; Gates, Ruth D.; Guannel, Greg; Mumby, Peter J.; Thomas, Hannah; Whitmee, Sarah; Woodley, Stephen; Fox, Helen E.

2017-03-01

Marine protected areas (MPAs) are increasingly being used globally to conserve marine resources. However, whether many MPAs are being effectively and equitably managed, and how MPA management influences substantive outcomes remain unknown. We developed a global database of management and fish population data (433 and 218 MPAs, respectively) to assess: MPA management processes; the effects of MPAs on fish populations; and relationships between management processes and ecological effects. Here we report that many MPAs failed to meet thresholds for effective and equitable management processes, with widespread shortfalls in staff and financial resources. Although 71% of MPAs positively influenced fish populations, these conservation impacts were highly variable. Staff and budget capacity were the strongest predictors of conservation impact: MPAs with adequate staff capacity had ecological effects 2.9 times greater than MPAs with inadequate capacity. Thus, continued global expansion of MPAs without adequate investment in human and financial capacity is likely to lead to sub-optimal conservation outcomes.

The middle-range theory of nursing intellectual capital.

PubMed

Covell, Christine L

2008-07-01

This paper is a report of the development of the middle-range theory of nursing intellectual capital. Rising healthcare costs and advances in technology have contributed to the need for better understanding of the influence of nurses' knowledge, skills and experience on patient and organizational outcomes. The middle-range nursing intellectual capital theory was developed using the strategies of concept and theory derivation. The principles of research synthesis were used to provide empirical support for the propositions of the theory. The middle-range nursing intellectual capital theory was derived from intellectual capital theory to make it relevant and applicable to a specific aspect of nursing, continuing professional development. It proposes that the nursing knowledge available in healthcare organizations is influenced by variables within the work environment, and influences patient and organizational outcomes. The middle-range nursing intellectual capital theory should be tested in different healthcare systems and in different settings and countries to determine its effectiveness in guiding research.

Open Versus Endovascular or Hybrid Thoracic Aortic Aneurysm Repair.

PubMed

Clare, Ryan; Jorgensen, Julianne; Brar, Somjot S

2016-10-01

Thoracic aortic aneurysms are associated with significant morbidity and mortality. There are multiple underlying etiologies, including genetic abnormalities, that have important implications in their natural history. The variable histologic, anatomic, and clinical presentations necessitate careful consideration of available treatment options. Surgical repair of these aneurysms has been the mainstay of treatment; however, these approaches can carry a relatively high risk of morbidity and mortality. Endovascular approaches have now become first-line therapy for descending thoracic aneurysms, and with advancements in graft technology, endovascular approaches are being increasingly employed for hybrid repairs of the aortic arch and even the ascending aorta. However, to date, clinical outcomes from randomized trials and long-term follow-up are limited. As technology continues to advance, there is the potential for further integration of surgical and endovascular treatments so that patients have the best opportunity for a favorable outcome.

Risk-adjusted monitoring of survival times

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

Sego, Landon H.; Reynolds, Marion R.; Woodall, William H.

2009-02-26

We consider the monitoring of clinical outcomes, where each patient has a di®erent risk of death prior to undergoing a health care procedure.We propose a risk-adjusted survival time CUSUM chart (RAST CUSUM) for monitoring clinical outcomes where the primary endpoint is a continuous, time-to-event variable that may be right censored. Risk adjustment is accomplished using accelerated failure time regression models. We compare the average run length performance of the RAST CUSUM chart to the risk-adjusted Bernoulli CUSUM chart, using data from cardiac surgeries to motivate the details of the comparison. The comparisons show that the RAST CUSUM chart is moremore » efficient at detecting a sudden decrease in the odds of death than the risk-adjusted Bernoulli CUSUM chart, especially when the fraction of censored observations is not too high. We also discuss the implementation of a prospective monitoring scheme using the RAST CUSUM chart.« less

HIV and HLA Class I: an evolving relationship

PubMed Central

Goulder, Philip J.R.; Walker, Bruce D

2014-01-01

Successful vaccine development for infectious diseases has largely been achieved in settings where natural immunity to the pathogen results in clearance in at least some individuals. HIV presents an additional challenge in that natural clearance of infection does not occur, and the correlates of immune protection are still uncertain. However, partial control of viremia and markedly different outcomes of disease are observed in HIV infected persons. Here we examine the antiviral mechanisms implicated by one variable that has been consistently associated with extremes of outcome, namely HLA class I alleles, and in particular HLA-B, and examine the mechanisms by which this modulation is likely to occur, and the impact of these interactions on evolution of the virus and the host. Studies to date provide evidence for both HLA-dependent and epitope-dependent influences on viral control and viral evolution, and have important implications for the continued quest for an effective HIV vaccine. PMID:22999948

How large must a treatment effect be before it matters to practitioners? An estimation method and demonstration.

PubMed

Miller, William R; Manuel, Jennifer Knapp

2008-09-01

Treatment research is sometimes criticised as lacking in clinical relevance, and one potential source of this friction is a disconnection between statistical significance and what clinicians regard to be a meaningful difference in outcomes. This report demonstrates a novel methodology for estimating what substance abuse practitioners regard to be clinically important differences. To illustrate the estimation method, we surveyed 50 substance abuse treatment providers participating in the National Institute on Drug Abuse (NIDA) Clinical Trials Network. Practitioners identified thresholds for clinically meaningful differences on nine common outcome variables, indicated the size of effect that would justify their learning a new treatment method and estimated current outcomes from their services. Clinicians judged a difference between two treatments to be meaningful if outcomes were improved by about 10 - 12 points on the percentage of patients totally abstaining, arrested for driving while intoxicated, employed or having abnormal liver enzymes. A 5 percentage-point reduction in patient mortality was regarded as clinically significant. On continuous outcome measures (such as percentage of days abstinent or drinks per drinking day), practitioners judged an outcome to be significant when it doubled or halved the base rate. When a new treatment meets such criteria, practitioners were interested in learning it. Effects that are statistically significant in clinical trials may be unimpressive to practitioners. Clinicians' judgements of meaningful differences can inform the powering of clinical trials.

A comparison of confidence interval methods for the intraclass correlation coefficient in community-based cluster randomization trials with a binary outcome.

PubMed

Braschel, Melissa C; Svec, Ivana; Darlington, Gerarda A; Donner, Allan

2016-04-01

Many investigators rely on previously published point estimates of the intraclass correlation coefficient rather than on their associated confidence intervals to determine the required size of a newly planned cluster randomized trial. Although confidence interval methods for the intraclass correlation coefficient that can be applied to community-based trials have been developed for a continuous outcome variable, fewer methods exist for a binary outcome variable. The aim of this study is to evaluate confidence interval methods for the intraclass correlation coefficient applied to binary outcomes in community intervention trials enrolling a small number of large clusters. Existing methods for confidence interval construction are examined and compared to a new ad hoc approach based on dividing clusters into a large number of smaller sub-clusters and subsequently applying existing methods to the resulting data. Monte Carlo simulation is used to assess the width and coverage of confidence intervals for the intraclass correlation coefficient based on Smith's large sample approximation of the standard error of the one-way analysis of variance estimator, an inverted modified Wald test for the Fleiss-Cuzick estimator, and intervals constructed using a bootstrap-t applied to a variance-stabilizing transformation of the intraclass correlation coefficient estimate. In addition, a new approach is applied in which clusters are randomly divided into a large number of smaller sub-clusters with the same methods applied to these data (with the exception of the bootstrap-t interval, which assumes large cluster sizes). These methods are also applied to a cluster randomized trial on adolescent tobacco use for illustration. When applied to a binary outcome variable in a small number of large clusters, existing confidence interval methods for the intraclass correlation coefficient provide poor coverage. However, confidence intervals constructed using the new approach combined with Smith's method provide nominal or close to nominal coverage when the intraclass correlation coefficient is small (<0.05), as is the case in most community intervention trials. This study concludes that when a binary outcome variable is measured in a small number of large clusters, confidence intervals for the intraclass correlation coefficient may be constructed by dividing existing clusters into sub-clusters (e.g. groups of 5) and using Smith's method. The resulting confidence intervals provide nominal or close to nominal coverage across a wide range of parameters when the intraclass correlation coefficient is small (<0.05). Application of this method should provide investigators with a better understanding of the uncertainty associated with a point estimator of the intraclass correlation coefficient used for determining the sample size needed for a newly designed community-based trial. © The Author(s) 2015.

Comparison of Patient Outcomes and Cost of Overlapping Versus Nonoverlapping Spine Surgery.

PubMed

Zygourakis, Corinna C; Sizdahkhani, Saman; Keefe, Malla; Lee, Janelle; Chou, Dean; Mummaneni, Praveen V; Ames, Christopher P

2017-04-01

Overlapping surgery recently has gained significant media attention, but there are limited data on its safety and efficacy. To date, there has been no analysis of overlapping surgery in the field of spine. Our goal was to compare overlapping versus nonoverlapping spine surgery patient outcomes and cost. A retrospective review was undertaken of 2319 spine surgeries (n = 848 overlapping; 1471 nonoverlapping) performed by 3 neurosurgery attendings from 2012 to 2015 at the University of California San Francisco. Collected variables included patient age, sex, insurance, American Society of Anesthesiology score, severity of illness, risk of mortality, procedure type, surgeon, day of surgery, source of transfer, admission type, overlapping versus nonoverlapping surgery (≥1 minute of overlapping procedure time), Medicare-Severity Diagnosis-Related Group, osteotomy, and presence of another attending/fellow/resident. Univariate, then multivariate mixed-effect models were used to evaluate the effect of the collected variables on the following outcomes: procedure time, estimated blood loss, length of stay, discharge status, 30-day mortality, 30-day unplanned readmission, unplanned return to OR, and total hospital cost. Urgent spine cases were more likely to be done in an overlapping fashion (all P < 0.01). After we adjusted for patient demographics, clinical indicators, and procedure characteristics, overlapping surgeries had longer procedure times (estimate = 26.17; P < 0.001) and lower rates of discharge to home (odds ratio 0.65; P < 0.001), but equivalent rates of 30-day mortality, readmission, return to the operating room, estimated blood loss, length of stay, and total hospital cost (all P = ns). Overlapping spine surgery may be performed safely at our institution, although continued monitoring of patient outcomes is necessary. Overlapping surgery does not lead to greater hospital costs. Copyright © 2017 Elsevier Inc. All rights reserved.

The outcomes of the elderly in acute care general surgery.

PubMed

St-Louis, E; Sudarshan, M; Al-Habboubi, M; El-Husseini Hassan, M; Deckelbaum, D L; Razek, T S; Feldman, L S; Khwaja, K

2016-02-01

Elderly patients form a growing subset of the acute care surgery (ACS) population. Older age may be associated with poorer outcomes for some elective procedures, but there are few studies focusing on outcomes for the elderly ACS population. Our objective is to characterize differences in mortality and morbidity for acute care surgery patients >80 years old. A retrospective review of all ACS admissions at a large teaching hospital over 1 year was conducted. Patients were classified into non-elderly (<80 years old) and elderly (≥80 years old). In addition to demographic differences, outcomes including care efficiency, mortality, postoperative complications, and length of stay were studied. Data analysis was completed with the Student's t test for continuous variables and Fisher's exact test for categorical variables using STATA 12 (College Station, TX, USA). We identified 467 non-elderly and 60 elderly patients with a mean age-adjusted Charlson score of 3.2 and 7.2, respectively (p < 0.001) and a mortality risk of 1.9 and 11.7 %, respectively (p < 0.001). The elderly were at risk of longer duration (>4 days) hospital stay (p = 0.05), increased postoperative complications (p = 0.002), admission to the ICU (p = 0.002), and were more likely to receive a non-operative procedure (p = 0.003). No difference was found (p = NS) for patient flow factors such as time to consult general surgery, time to see consult by general surgery, and time to operative management and disposition. Compared to younger patients admitted to an acute care surgery service, patients over 80 years old have a higher risk of complications, are more likely to require ICU admission, and stay longer in the hospital.

Outcome of transarterial treatment of dural arteriovenous fistulas with direct or indirect cortical venous drainage.

PubMed

Mantilla, Daniel; Le Corre, Marine; Cagnazzo, Federico; Gascou, Gregory; Eker, Omer; Machi, Paolo; Riquelme, Carlos; Dargazanli, Cyril; Costalat, Vincent; Bonafe, Alain; Lefevre, Pierre-Henri

2018-01-30

Transarterial Onyx embolization is an effective treatment for patients with intracranial dural arteriovenous fistula (DAVF). A study was performed to determine whether the clinical and radiological outcomes after transarterial Onyx treatment were affected by the type of cortical venous drainage (direct vs indirect) of high-grade DAVF. Between May 2006 and December 2014, demographic data, clinical presentation, angiographic characteristics, and treatment-related outcomes were collected for 54 patients divided into two groups (intracranial DAVF with direct and indirect cortical venous drainage). Continuous variables were compared with the two-tailed t test and categorical variables with the χ 2 test. Statistical significance was set at P<0.05. Fifty-two patients (71% with direct and 29% with indirect cortical venous drainage) underwent Onyx embolization. Immediate complete occlusion after treatment was observed in about 55% of patients without between-group difference. During the long-term follow-up, complete angiographic occlusion was achieved in 83% of patients. Specifically, 15 additional patients (40%) in the direct cortical venous drainage group progressed to complete occlusion, but only one (6%) in the indirect cortical venous drainage group. Overall, the rate of complete occlusion was higher in patients with DAVF with direct cortical venous drainage (92%) than in those with DAVF with indirect cortical venous drainage (62.5%) (P=0.01). The rate of permanent treatment-related complications was 4%, mostly related to ischemic events. Overall, 80.5% of patients had a good neurological outcome (modified Rankin Scale score 0-2). Transarterial Onyx embolization of intracranial high-grade DAVF is safe and effective, particularly for lesions with direct cortical venous drainage. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Stronger steerability criterion for more uncertain continuous-variable systems

NASA Astrophysics Data System (ADS)

Chowdhury, Priyanka; Pramanik, Tanumoy; Majumdar, A. S.

2015-10-01

We derive a fine-grained uncertainty relation for the measurement of two incompatible observables on a single quantum system of continuous variables, and show that continuous-variable systems are more uncertain than discrete-variable systems. Using the derived fine-grained uncertainty relation, we formulate a stronger steering criterion that is able to reveal the steerability of NOON states that has hitherto not been possible using other criteria. We further obtain a monogamy relation for our steering inequality which leads to an, in principle, improved lower bound on the secret key rate of a one-sided device independent quantum key distribution protocol for continuous variables.

Robustness of quantum key distribution with discrete and continuous variables to channel noise

NASA Astrophysics Data System (ADS)

Lasota, Mikołaj; Filip, Radim; Usenko, Vladyslav C.

2017-06-01

We study the robustness of quantum key distribution protocols using discrete or continuous variables to the channel noise. We introduce the model of such noise based on coupling of the signal to a thermal reservoir, typical for continuous-variable quantum key distribution, to the discrete-variable case. Then we perform a comparison of the bounds on the tolerable channel noise between these two kinds of protocols using the same noise parametrization, in the case of implementation which is perfect otherwise. Obtained results show that continuous-variable protocols can exhibit similar robustness to the channel noise when the transmittance of the channel is relatively high. However, for strong loss discrete-variable protocols are superior and can overcome even the infinite-squeezing continuous-variable protocol while using limited nonclassical resources. The requirement on the probability of a single-photon production which would have to be fulfilled by a practical source of photons in order to demonstrate such superiority is feasible thanks to the recent rapid development in this field.

Analysis of SBIR phase I and phase II review results at the National Institutes of Health.

PubMed

Vener, K J; Calkins, B M

1991-09-01

A cohort of phase I and phase II summary statements for the SBIR grant applications was evaluated to determine the strengths and weaknesses in approved and disapproved applications. An analysis of outcome variables (disapproval or unfunded status) was examined with respect to exposure variables (strengths or shortcomings). Logistic regression models were developed for comparisons to measure the predictive value of shortcomings and strengths to the outcomes. Disapproved phase I results were compared with an earlier 1985 study. Although the magnitude of the frequencies of shortcomings was greater in the present study, the relative rankings within shortcoming class were more alike than different. Also, the frequencies of shortcomings were, with one exception, not significantly different in the two studies. Differences in the summary statement review may have accounted for some differences observed between the 1985 data and results of the present study. Comparisons of Approved/Disapproved and Approved-Unfunded/Funded yielded the following observations. For phase I applicants, a lack of a clearly stated, testable hypothesis, a poorly qualified or described investigative team, and inadequate methodological approaches contributed significantly (in that order) to a rating of disapproval. A critical flaw for phase II proposals was failure to accomplish objectives of the phase I study. Methodological issues also dominate the distinctions in both comparison groups. A clear result of the data presented here and that published previously is that SBIR applicants need continuing assistance to improve the chances of their success. These results should serve as a guide to assist NIH staff as they provide information to prospective applicants focusing on key elements of the application. A continuing review of the SBIR program would be helpful to evaluate the quality of the submitted science.

Self-Efficacy and Short-Term Adherence to Continuous Positive Airway Pressure Treatment in Children.

PubMed

Xanthopoulos, Melissa S; Kim, Ji Young; Blechner, Michael; Chang, Ming-Yu; Menello, Mary Kate; Brown, Christina; Matthews, Edward; Weaver, Terri E; Shults, Justine; Marcus, Carole L

2017-07-01

Infants, children, and adolescents are increasingly being prescribed continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnea syndrome (OSAS), yet adherence is often poor. The purpose of this study was to examine the relationship between caregiver and patient-reported health cognitions about CPAP prior to starting CPAP and CPAP adherence at 1 month. We hypothesized that greater caregiver-reported self-efficacy would be positively associated with CPAP adherence in children. We also evaluated patient-reported self-efficacy and caregiver- and patient-reported risk perception and outcome expectations as they related to adherence, as well as how demographic factors influenced these relationships. A pediatric modification of the Self-Efficacy Measure for Sleep Apnea Questionnaire was administered to children and adolescents with OSAS-prescribed CPAP and their caregivers during the clinical CPAP-initiation visit. The primary outcome variable for adherence was the average total minutes of CPAP usage across all days from the date that CPAP was initiated to 31 days later. Unadjusted ordinary least-square regression showed a significant association between caregiver-reported self-efficacy and adherence (p = .007), indicating that mean daily CPAP usage increased by 48.4 minutes when caregiver-reported self-efficacy increased by one point (95% confidence interval 13.4-83.4 minutes). No other caregiver- or patient-reported cognitive health variables were related to CPAP use. This study indicates that caregiver CPAP-specific self-efficacy is an important factor to consider when starting youth on CPAP therapy for OSAS. Employing strategies to improve caregiver self-efficacy, beginning at CPAP initiation, may promote CPAP adherence. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

International Quit and Win 1996: comparative evaluation study in China and Finland

PubMed Central

Sun, S.; Korhonen, T.; Uutela, A.; Korhonen, H.; Puska, P.; Jun, Y.; Chonghua, Y.; Zeyu, G.; Yonghao, W.; Wenqing, X.

2000-01-01

OBJECTIVES—To compare background and process variables, as well as follow up status, of the participants in the International Quit and Win '96 contests of China and Finland, and analyse factors contributing to sustained maintenance.
DESIGN—A standardised 12 month follow up was conducted in both countries with random samples of participants. The sample sizes were 3119 in China and 1448 in Finland, with response rates of 91.2% and 65.2%, respectively.
INTERVENTIONS—The International Quit and Win '96 contest was the second coordinated, multinational smoking cessation campaign targeted at adult daily smokers. Altogether 25 countries participated, including China with 15 000 and Finland with 6000 smokers registered.
MAIN OUTCOME MEASURES—Conservative (considering all non-respondents relapsed) and non-conservative (based on respondents only) estimates were calculated for one month abstinence, 12 month continuous abstinence, and point abstinence at the time point of follow up.
RESULTS—Great differences were found in the background and process variables, as well as in the outcome measures. At one year follow up, the conservative continuous abstinence rates show that the Chinese participants maintained their abstinence better (38%) compared to the Finnish ones (12%). In China women reached higher abstinence rate (50%) than men (36%), whereas in Finland men achieved a better result (14%) than women (9%).
CONCLUSIONS—The Quit and Win contest is a mass smoking cessation method feasible in countries showing great variance in smoking habits and rates. However, in countries with different stages of anti-smoking development, such as China and Finland, different practical implementation strategies may be needed.


Keywords: smoking cessation; Quit and Win; China; Finland PMID:10982574

The effectiveness of exercise for the management of musculoskeletal disorders and injuries of the elbow, forearm, wrist, and hand: a systematic review by the Ontario Protocol for Traffic Injury Management (OPTIMa) collaboration.

PubMed

Menta, Roger; Randhawa, Kristi; Côté, Pierre; Wong, Jessica J; Yu, Hainan; Sutton, Deborah; Varatharajan, Sharanya; Southerst, Danielle; D'Angelo, Kevin; Cox, Jocelyn; Brown, Courtney; Dion, Sarah; Mior, Silvano; Stupar, Maja; Shearer, Heather M; Lindsay, Gail M; Jacobs, Craig; Taylor-Vaisey, Anne

2015-09-01

The purpose of this systematic review was to evaluate the effectiveness of exercise compared to other interventions, placebo/sham intervention, or no intervention in improving self-rated recovery, functional recovery, clinical, and/or administrative outcomes in individuals with musculoskeletal disorders and injuries of the elbow, forearm, wrist, and hand. We searched MEDLINE, EMBASE, CINAHL, PsycINFO, and the Cochrane Central Register of Controlled Trials from 1990 to 2015. Paired reviewers independently screened studies for relevance and assessed the risk of bias using the Scottish Intercollegiate Guidelines Network criteria. We synthesized the evidence using the best evidence synthesis methodology. We identified 5 studies with a low risk of bias. Our review suggests that, for patients with persistent lateral epicondylitis, (1) adding concentric or eccentric strengthening exercises to home stretching exercises provides no additional benefits; (2) a home program of either eccentric or concentric strengthening exercises leads to similar outcomes; (3) home wrist extensor strengthening exercises lead to greater short-term improvements in pain reduction compared to "wait and see"; and (4) clinic-based, supervised exercise may be more beneficial than home exercises with minimal improvements in pain and function. For hand pain of variable duration, supervised progressive strength training added to advice to continue normal physical activity provides no additional benefits. The relative effectiveness of stretching vs strengthening for the wrist extensors remains unknown for the management of persistent lateral epicondylitis. The current evidence shows that the addition of supervised progressive strength training does not provide further benefits over advice to continue normal physical activity for hand pain of variable duration. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Evaluating the learning curve for robot-assisted laparoscopic radical cystectomy.

PubMed

Pruthi, Raj S; Smith, Angela; Wallen, Eric M

2008-11-01

We seek to describe the learning curve of robot-assisted laparoscopic radical cystectomy by evaluating some of the surgical, oncologic, and clinical outcomes in our initial experience with 50 consecutive patients undergoing this novel procedure. Fifty consecutive patients (representing our initial experience with robot-assisted cystectomy) underwent radical cystectomy and urinary diversion from January 2006 to December 2007. Several different metrics were used to evaluate the learning curve of this procedure, including estimated blood loss (EBL), operative (OR) time, pathologic outcomes, and complication rate. We evaluated patients as a continuous variable, divided into five distinct time periods (quintiles), and stratified by first half and second half of robotic experience. EBL was not significantly lower until the third quintile (patients 21-30), after which further significant reductions were not observed. Mean OR time declined between each quintile for the first 30 patients (1-10 v 11-20 v 21-30). No significant declines occurred after the third quintile (21-30). When evaluated as a continuous variable, the statistical cut point at which no further significant reductions were observed was after patient 20 for OR time. No differences were observed with regard to time to flatus, bowel movement, or hospital discharge. Furthermore, complications were not different between the initial 25 patients and the most recent patients. There has been no case of a positive margin, and there was only one inadvertent bladder entry. Lymph node yield has also not significantly changed over time. This report helps to define the learning curve associated with robot-assisted laparoscopic radical cystectomy for bladder cancer. Despite the higher OR times and blood loss that is observed early in the learning curve, no such compromises are observed with regard to these oncologic parameters even early in the experience.

Can Infants Be "Taught" to Attend to a New Physical Variable in an Event Category? The Case of Height in Covering Events

ERIC Educational Resources Information Center

Wang, Su-hua; Baillargeon, Renee

2008-01-01

As they observe or produce events, infants identify variables that help them predict outcomes in each category of events. How do infants identify a new variable? An explanation-based learning (EBL) account suggests three essential steps: (1) observing contrastive outcomes relevant to the variable; (2) discovering the conditions associated with…

Using Propensity Score Methods to Approximate Factorial Experimental Designs to Analyze the Relationship between Two Variables and an Outcome

ERIC Educational Resources Information Center

Dong, Nianbo

2015-01-01

Researchers have become increasingly interested in programs' main and interaction effects of two variables (A and B, e.g., two treatment variables or one treatment variable and one moderator) on outcomes. A challenge for estimating main and interaction effects is to eliminate selection bias across A-by-B groups. I introduce Rubin's causal model to…

Fifty Years of Research in ARDS. Respiratory Mechanics in Acute Respiratory Distress Syndrome.

PubMed

Henderson, William R; Chen, Lu; Amato, Marcelo B P; Brochard, Laurent J

2017-10-01

Acute respiratory distress syndrome is a multifactorial lung injury that continues to be associated with high levels of morbidity and mortality. Mechanical ventilation, although lifesaving, is associated with new iatrogenic injury. Current best practice involves the use of small Vt, low plateau and driving pressures, and high levels of positive end-expiratory pressure. Collectively, these interventions are termed "lung-protective ventilation." Recent investigations suggest that individualized measurements of pulmonary mechanical variables rather than population-based ventilation prescriptions may be used to set the ventilator with the potential to improve outcomes beyond those achieved with standard lung protective ventilation. This review outlines the measurement and application of clinically applicable pulmonary mechanical concepts, such as plateau pressures, driving pressure, transpulmonary pressures, stress index, and measurement of strain. In addition, the concept of the "baby lung" and the utility of dynamic in addition to static measures of pulmonary mechanical variables are discussed.

An opinion-driven behavioral dynamics model for addictive behaviors

NASA Astrophysics Data System (ADS)

Moore, Thomas W.; Finley, Patrick D.; Apelberg, Benjamin J.; Ambrose, Bridget K.; Brodsky, Nancy S.; Brown, Theresa J.; Husten, Corinne; Glass, Robert J.

2015-04-01

We present a model of behavioral dynamics that combines a social network-based opinion dynamics model with behavioral mapping. The behavioral component is discrete and history-dependent to represent situations in which an individual's behavior is initially driven by opinion and later constrained by physiological or psychological conditions that serve to maintain the behavior. Individuals are modeled as nodes in a social network connected by directed edges. Parameter sweeps illustrate model behavior and the effects of individual parameters and parameter interactions on model results. Mapping a continuous opinion variable into a discrete behavioral space induces clustering on directed networks. Clusters provide targets of opportunity for influencing the network state; however, the smaller the network the greater the stochasticity and potential variability in outcomes. This has implications both for behaviors that are influenced by close relationships verses those influenced by societal norms and for the effectiveness of strategies for influencing those behaviors.

Warfarin therapy: in need of improvement after all these years

PubMed Central

Kimmel, Stephen E

2010-01-01

Background Warfarin therapy has been used clinically for over 60 years, yet continues to be problematic because of its narrow therapeutic index and large inter-individual variability in patient response. As a result, warfarin is a leading cause of serious medication-related adverse events, and its efficacy is also suboptimal. Objective To review factors that are responsible for variable response to warfarin, including clinical, environmental, and genetic factors, and to explore some possible approaches to improving warfarin therapy. Results Recent efforts have focused on developing dosing algorithms that included genetic information to try to improve warfarin dosing. These dosing algorithms hold promise, but have not been fully validated or tested in rigorous clinical trials. Perhaps equally importantly, adherence to warfarin is a major problem that should be addressed with innovative and cost-effective interventions. Conclusion Additional research is needed to further test whether interventions can be used to improve warfarin dosing and outcomes. PMID:18345947

The Aristotle Comprehensive Complexity score predicts mortality and morbidity after congenital heart surgery.

PubMed

Bojan, Mirela; Gerelli, Sébastien; Gioanni, Simone; Pouard, Philippe; Vouhé, Pascal

2011-04-01

The Aristotle Comprehensive Complexity (ACC) score has been proposed for complexity adjustment in the analysis of outcome after congenital heart surgery. The score is the sum of the Aristotle Basic Complexity score, largely used but poorly related to mortality and morbidity, and of the Comprehensive Complexity items accounting for comorbidities and procedure-specific and anatomic variability. This study aims to demonstrate the ability of the ACC score to predict 30-day mortality and morbidity assessed by the length of the intensive care unit (ICU) stay. We retrospectively enrolled patients undergoing congenital heart surgery in our institution. We modeled the ACC score as a continuous variable, mortality as a binary variable, and length of ICU stay as a censored variable. For each mortality and morbidity model we performed internal validation by bootstrapping and assessed overall performance by R(2), calibration by the calibration slope, and discrimination by the c index. Among all 1,454 patients enrolled, 30-day mortality rate was 3.4% and median length of ICU stay was 3 days. The ACC score strongly related to mortality, but related to length of ICU stay only during the first postoperative week. For the mortality model, R(2) = 0.24, calibration slope = 0.98, c index = 0.86, and 95% confidence interval was 0.82 to 0.91. For the morbidity model, R(2) = 0.094, calibration slope = 0.94, c index = 0.64, and 95% confidence interval was 0.62 to 0.66. The ACC score predicts 30-day mortality and length of ICU stay during the first postoperative week. The score is an adequate tool for complexity adjustment in the analysis of outcome after congenital heart surgery. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Studies of educational interventions and outcomes in diabetic adults: a meta-analysis revisited.

PubMed

Brown, S A

1990-12-01

This paper reports a follow-up of previous meta-analysis research conducted by the author on the effects of diabetes patient education on patient outcomes. An expanded sample of studies and psychological outcome variables were added to the previously studied variables of patient knowledge, self-care behaviors (compliance and skill performance) and metabolic control. The purpose was to determine: (1) the effects of patient education on specific outcome variables; and (2) the relationships between effects of education and characteristics of the studies and/or subjects. Following an extensive literature search, a total of 82 studies were found which met the inclusion criteria for this analysis; 68% were published and 32% were unpublished. Homogeneity analyses of specific patient outcome variables yielded the following results: knowledge effects ranged from 0.49 to 1.05; self-care behavior effects from 0.17 to 0.57, with insulin injection and weight loss associated with the smallest effect sizes; metabolic control from 0.16 to 0.41; and psychological outcomes 0.27. Mean age of the subjects was negatively correlated with knowledge and cholesterol, indicating that the older the mean age of the subjects, the lower the effects of patient education on these variables. Findings of this meta-analysis on the expanded data set were consistent with the previous meta-analysis and lend support to the effectiveness of diabetes patient education in improving patient outcomes.

Birth Order and health: major issues.

PubMed

Elliott, B A

1992-08-01

Birth Order has been described as a variable with a complex relationship to child and adult outcomes. A review of the medical literature over the past 5 years identified 20 studies that investigated the relationship between Birth Order and a health outcome. Only one of the studies established a relationship between Birth Order and a health outcome: third and fourth-born children have a higher incidence of accidents that result in hospitalization. The other demonstrated relationships are each explained by intervening variables or methodological limitations. Although Birth Order is not a strongly independent explanatory factor in understanding health outcomes, it is an important marker variable. Statistically significant relationships between Birth Order and health outcomes yield insights into the ways a family influences an individual's health.

Robotic-Assisted Knee Arthroplasty: An Overview.

PubMed

van der List, Jelle P; Chawla, Harshvardhan; Pearle, Andrew D

2016-01-01

Unicompartmental knee arthroplasty and total knee arthroplasty are reliable treatment options for osteoarthritis. In order to improve survivorship rates, variables that are intraoperatively controlled by the orthopedic surgeon are being evaluated. These variables include lower leg alignment, soft tissue balance, joint line maintenance, and tibial and femoral component alignment, size, and fixation methods. Since tighter control of these factors is associated with improved outcomes of knee arthroplasty, several computer-assisted surgery systems have been developed. These systems differ in the number and type of variables they control. Robotic-assisted systems control these aforementioned variables and, in addition, aim to improve the surgical precision of the procedure. Robotic-assisted systems are active, semi-active, or passive, depending on how independently the systems perform maneuvers. Reviewing the robotic-assisted knee arthroplasty systems, it becomes clear that these systems can accurately and reliably control the aforementioned variables. Moreover, these systems are more accurate and reliable in controlling these variables when compared to the current gold standard of conventional manual surgery. At present, few studies have assessed the survivorship and functional outcomes of robotic-assisted surgery, and no sufficiently powered studies were identified that compared survivorship or functional outcomes between robotic-assisted and conventional knee arthroplasty. Although preliminary outcomes of robotic-assisted surgery look promising, more studies are necessary to assess if the increased accuracy and reliability in controlling the surgical variables leads to better outcomes of robotic-assisted knee arthroplasty.

Method and apparatus for executing an asynchronous clutch-to-clutch shift in a hybrid transmission

DOEpatents

Demirovic, Besim; Gupta, Pinaki; Kaminsky, Lawrence A.; Naqvi, Ali K.; Heap, Anthony H.; Sah, Jy-Jen F.

2014-08-12

A hybrid transmission includes first and second electric machines. A method for operating the hybrid transmission in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode includes increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode. Upon deactivation of the off-going clutch, torque outputs of the first and second electric machines and the torque of the oncoming clutch are controlled to synchronize the oncoming clutch. Upon synchronization of the oncoming clutch, the torque for the oncoming clutch is increased and the transmission is operated in the target continuously variable mode.

High Variability in Outcome Reporting Patterns in High-Impact ACL Literature.

PubMed

Makhni, Eric C; Padaki, Ajay S; Petridis, Petros D; Steinhaus, Michael E; Ahmad, Christopher S; Cole, Brian J; Bach, Bernard R

2015-09-16

ACL (anterior cruciate ligament) reconstruction is one of the most commonly performed and studied procedures in modern sports medicine. A multitude of objective and subjective patient outcome measures exists; however, nonstandardized reporting patterns of these metrics may create challenges in objectively analyzing pooled results from different studies. The goal of this study was to document the variability in outcome reporting patterns in high-impact orthopaedic studies of ACL reconstruction. All clinical studies pertaining to ACL reconstruction in four high-impact-factor orthopaedic journals over a five-year period were reviewed. Biomechanical, basic science, and imaging studies were excluded, as were studies with fewer than fifty patients, yielding 119 studies for review. Incorporation of various objective and subjective outcomes was noted for each study. Substantial variability in reporting of both objective and subjective measures was noted in the study cohort. Although a majority of studies reported instrumented laxity findings, there was substantial variability in the type and method of laxity reporting. Most other objective outcomes, including range of motion, strength, and complications, were reported in <50% of all studies. Return to pre-injury level of activity was infrequently reported (24% of studies), as were patient satisfaction and pain assessment following surgery (8% and 13%, respectively). Of the patient-reported outcomes, the International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores were most often reported (71%, 63%, and 42%, respectively). Substantial variability in outcome reporting patterns exists among high-impact studies of ACL reconstruction. Such variability may create challenges in interpreting results and pooling them across different studies. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Smoking cessation and outcome after ischemic stroke or TIA.

PubMed

Epstein, Katherine A; Viscoli, Catherine M; Spence, J David; Young, Lawrence H; Inzucchi, Silvio E; Gorman, Mark; Gerstenhaber, Brett; Guarino, Peter D; Dixit, Anand; Furie, Karen L; Kernan, Walter N

2017-10-17

To assess whether smoking cessation after an ischemic stroke or TIA improves outcomes compared to continued smoking. We conducted a prospective observational cohort study of 3,876 nondiabetic men and women enrolled in the Insulin Resistance Intervention After Stroke (IRIS) trial who were randomized to pioglitazone or placebo within 180 days of a qualifying stroke or TIA and followed up for a median of 4.8 years. A tobacco use history was obtained at baseline and updated during annual interviews. The primary outcome, which was not prespecified in the IRIS protocol, was recurrent stroke, myocardial infarction (MI), or death. Cox regression models were used to assess the differences in stroke, MI, and death after 4.8 years, with correction for adjustment variables prespecified in the IRIS trial: age, sex, stroke (vs TIA) as index event, history of stroke, history of hypertension, history of coronary artery disease, and systolic and diastolic blood pressures. At the time of their index event, 1,072 (28%) patients were current smokers. By the time of randomization, 450 (42%) patients had quit smoking. Among quitters, the 5-year risk of stroke, MI, or death was 15.7% compared to 22.6% for patients who continued to smoke (adjusted hazard ratio 0.66, 95% confidence interval 0.48-0.90). Cessation of cigarette smoking after an ischemic stroke or TIA was associated with significant health benefits over 4.8 years in the IRIS trial cohort. © 2017 American Academy of Neurology.

Nursing intellectual capital theory: testing selected propositions.

PubMed

Covell, Christine L; Sidani, Souraya

2013-11-01

To test the selected propositions of the middle-range theory of nursing intellectual capital. The nursing intellectual capital theory conceptualizes nursing knowledge's influence on patient and organizational outcomes. The theory proposes nursing human capital, nurses' knowledge, skills and experience, is related to the quality of patient care and nurse recruitment and retention of an inpatient care unit. Two factors in the work environment, nurse staffing and employer support for nurse continuing professional development, are proposed to influence nursing human capital's association with patient and organizational outcomes. A cross-sectional survey design. The study took place in 2008 in six Canadian acute care hospitals. Financial, human resource and risk data were collected from hospital departments and unit managers. Clearly specified empirical indicators quantified the study variables. The propositions of the theory were tested with data from 91 inpatient care units using structural equation modelling. The propositions associated with the nursing human capital concept were supported. The propositions associated with the employer support for nurse continuing professional development concept were not. The proposition that nurse staffing's influences on patient outcomes was mediated by the nursing human capital of an inpatient unit, was partially supported. Some of the theory's propositions were empirically validated. Additional theoretical work is needed to refine the operationalization and measurement of some of the theory's concepts. Further research with larger samples of data from different geographical settings and types of hospitals is required to determine if the theory can withstand empirical scrutiny. © 2013 Blackwell Publishing Ltd.

Stroke disease management--a framework for comprehensive stroke care.

PubMed

Venketasubramanian, N; Chan, B P L; Lim, E; Hafizah, Noor; Goh, K T; Lew, Y J; Loo, L; Yin, A; Widjaja, L; Loke, W C; Kuick, G; Lee, N L; Ong, B S; Koh, S F; Heng, B H; Cheah, J

2002-07-01

Disease management is an approach to patient care that coordinates medical resources for the patient across the entire healthcare delivery system throughout the lifetime of the patient with the disease. Stroke is suitable for disease management as it is a well-known disease with a high prevalence, high cost, variable practice pattern, poor clinical outcome, and managed by a non-integrated healthcare system. It has measurable and actionable outcomes, with available local expertise and support of the Ministry of Health. Developing the programme requires a multidisciplinary team, baseline data on target populations and healthcare services, identification of core components, collaboration with key stakeholders, development of evidence-based clinical practice guidelines and carepaths, institution of care coordinators, use of information technology and continuous quality improvement to produce an effective plan. Core components include public education, risk factor screening and management, primary care and specialist clinics, acute stroke units, inpatient and outpatient rehabilitation facilities, and supportive community services including medical, nursing, therapy, home help and support groups for patients and carers. The family physician plays a key role. Coordination of services is best done by a network of hospital and community-based care managers, and is enhanced by a coordinating call centre. Continuous quality improvement is required, with audit of processes and outcomes, facilitated by a disease registry. Pitfalls include inappropriate exclusion of deserving patients, misuse, loss of physician and patient independence, over-estimation of benefits, and care fragmentation. Collaboration and cooperative among all parties will help ensure a successful and sustainable programme.

Power calculator for instrumental variable analysis in pharmacoepidemiology

PubMed Central

Walker, Venexia M; Davies, Neil M; Windmeijer, Frank; Burgess, Stephen; Martin, Richard M

2017-01-01

Abstract Background Instrumental variable analysis, for example with physicians’ prescribing preferences as an instrument for medications issued in primary care, is an increasingly popular method in the field of pharmacoepidemiology. Existing power calculators for studies using instrumental variable analysis, such as Mendelian randomization power calculators, do not allow for the structure of research questions in this field. This is because the analysis in pharmacoepidemiology will typically have stronger instruments and detect larger causal effects than in other fields. Consequently, there is a need for dedicated power calculators for pharmacoepidemiological research. Methods and Results The formula for calculating the power of a study using instrumental variable analysis in the context of pharmacoepidemiology is derived before being validated by a simulation study. The formula is applicable for studies using a single binary instrument to analyse the causal effect of a binary exposure on a continuous outcome. An online calculator, as well as packages in both R and Stata, are provided for the implementation of the formula by others. Conclusions The statistical power of instrumental variable analysis in pharmacoepidemiological studies to detect a clinically meaningful treatment effect is an important consideration. Research questions in this field have distinct structures that must be accounted for when calculating power. The formula presented differs from existing instrumental variable power formulae due to its parametrization, which is designed specifically for ease of use by pharmacoepidemiologists. PMID:28575313

Clinical Trials With Large Numbers of Variables: Important Advantages of Canonical Analysis.

PubMed

Cleophas, Ton J

2016-01-01

Canonical analysis assesses the combined effects of a set of predictor variables on a set of outcome variables, but it is little used in clinical trials despite the omnipresence of multiple variables. The aim of this study was to assess the performance of canonical analysis as compared with traditional multivariate methods using multivariate analysis of covariance (MANCOVA). As an example, a simulated data file with 12 gene expression levels and 4 drug efficacy scores was used. The correlation coefficient between the 12 predictor and 4 outcome variables was 0.87 (P = 0.0001) meaning that 76% of the variability in the outcome variables was explained by the 12 covariates. Repeated testing after the removal of 5 unimportant predictor and 1 outcome variable produced virtually the same overall result. The MANCOVA identified identical unimportant variables, but it was unable to provide overall statistics. (1) Canonical analysis is remarkable, because it can handle many more variables than traditional multivariate methods such as MANCOVA can. (2) At the same time, it accounts for the relative importance of the separate variables, their interactions and differences in units. (3) Canonical analysis provides overall statistics of the effects of sets of variables, whereas traditional multivariate methods only provide the statistics of the separate variables. (4) Unlike other methods for combining the effects of multiple variables such as factor analysis/partial least squares, canonical analysis is scientifically entirely rigorous. (5) Limitations include that it is less flexible than factor analysis/partial least squares, because only 2 sets of variables are used and because multiple solutions instead of one is offered. We do hope that this article will stimulate clinical investigators to start using this remarkable method.

Value of intracochlear electrically evoked auditory brainstem response after cochlear implantation in patients with narrow internal auditory canal.

PubMed

Song, Mee Hyun; Bae, Mi Ran; Kim, Hee Nam; Lee, Won-Sang; Yang, Won Sun; Choi, Jae Young

2010-08-01

Cochlear implantation in patients with narrow internal auditory canal (IAC) can result in variable outcomes; however, preoperative evaluations have limitations in accurately predicting outcomes. In this study, we analyzed the outcomes of cochlear implantation in patients with narrow IAC and correlated the intracochlear electrically evoked auditory brainstem response (EABR) findings to postoperative performance to determine the prognostic significance of intracochlear EABR. Retrospective case series at a tertiary hospital. Thirteen profoundly deaf patients with narrow IAC who received cochlear implantation from 2002 to 2008 were included in this study. Postoperative performance was evaluated after at least 12 months of follow-up, and postoperative intracochlear EABR was measured to determine its correlation with outcome. The clinical significance of electrically evoked compound action potential (ECAP) was also analyzed. Patients with narrow IAC showed postoperative auditory performances ranging from CAP 0 to 4 after cochlear implantation. Intracochlear EABR measured postoperatively demonstrated prognostic value in the prediction of long-term outcomes, whereas ECAP measurements failed to show a significant correlation with outcome. Consistent with the advantages of intracochlear EABR over extracochlear EABR, this study demonstrates that intracochlear EABR has prognostic significance in predicting long-term outcomes in patients with narrow IAC. Intracochlear EABR measured either intraoperatively or in the early postoperative period may play an important role in deciding whether to continue with auditory rehabilitation using a cochlear implant or to switch to an auditory brainstem implant so as not to miss the optimal timing for language development.

Peer Educators and Close Friends as Predictors of Male College Students' Willingness to Prevent Rape

ERIC Educational Resources Information Center

Stein, Jerrold L.

2007-01-01

Astin's (1977, 1991, 1993) input-environment-outcome (I-E-O) model provided a conceptual framework for this study which measured 156 male college students' willingness to prevent rape (outcome variable). Predictor variables included personal attitudes (input variable), perceptions of close friends' attitudes toward rape and rape prevention…

A Conceptual Framework for Graduate Teaching Assistant Professional Development Evaluation and Research

PubMed Central

Reeves, Todd D.; Marbach-Ad, Gili; Miller, Kristen R.; Ridgway, Judith; Gardner, Grant E.; Schussler, Elisabeth E.; Wischusen, E. William

2016-01-01

Biology graduate teaching assistants (GTAs) are significant contributors to the educational mission of universities, particularly in introductory courses, yet there is a lack of empirical data on how to best prepare them for their teaching roles. This essay proposes a conceptual framework for biology GTA teaching professional development (TPD) program evaluation and research with three overarching variable categories for consideration: outcome variables, contextual variables, and moderating variables. The framework’s outcome variables go beyond GTA satisfaction and instead position GTA cognition, GTA teaching practice, and undergraduate learning outcomes as the foci of GTA TPD evaluation and research. For each GTA TPD outcome variable, key evaluation questions and example assessment instruments are introduced to demonstrate how the framework can be used to guide GTA TPD evaluation and research plans. A common conceptual framework is also essential to coordinating the collection and synthesis of empirical data on GTA TPD nationally. Thus, the proposed conceptual framework serves as both a guide for conducting GTA TPD evaluation at single institutions and as a means to coordinate research across institutions at a national level. PMID:27193291

Ancilla-driven quantum computation for qudits and continuous variables

NASA Astrophysics Data System (ADS)

Proctor, Timothy; Giulian, Melissa; Korolkova, Natalia; Andersson, Erika; Kendon, Viv

2017-05-01

Although qubits are the leading candidate for the basic elements in a quantum computer, there are also a range of reasons to consider using higher-dimensional qudits or quantum continuous variables (QCVs). In this paper, we use a general "quantum variable" formalism to propose a method of quantum computation in which ancillas are used to mediate gates on a well-isolated "quantum memory" register and which may be applied to the setting of qubits, qudits (for d >2 ), or QCVs. More specifically, we present a model in which universal quantum computation may be implemented on a register using only repeated applications of a single fixed two-body ancilla-register interaction gate, ancillas prepared in a single state, and local measurements of these ancillas. In order to maintain determinism in the computation, adaptive measurements via a classical feed forward of measurement outcomes are used, with the method similar to that in measurement-based quantum computation (MBQC). We show that our model has the same hybrid quantum-classical processing advantages as MBQC, including the power to implement any Clifford circuit in essentially one layer of quantum computation. In some physical settings, high-quality measurements of the ancillas may be highly challenging or not possible, and hence we also present a globally unitary model which replaces the need for measurements of the ancillas with the requirement for ancillas to be prepared in states from a fixed orthonormal basis. Finally, we discuss settings in which these models may be of practical interest.

Econometrics in outcomes research: the use of instrumental variables.

PubMed

Newhouse, J P; McClellan, M

1998-01-01

We describe an econometric technique, instrumental variables, that can be useful in estimating the effectiveness of clinical treatments in situations when a controlled trial has not or cannot be done. This technique relies upon the existence of one or more variables that induce substantial variation in the treatment variable but have no direct effect on the outcome variable of interest. We illustrate the use of the technique with an application to aggressive treatment of acute myocardial infarction in the elderly.

Perioperative outcomes for pediatric neurosurgical procedures: analysis of the National Surgical Quality Improvement Program-Pediatrics.

PubMed

Kuo, Benjamin J; Vissoci, Joao Ricardo N; Egger, Joseph R; Smith, Emily R; Grant, Gerald A; Haglund, Michael M; Rice, Henry E

2017-03-01

OBJECTIVE Existing studies have shown a high overall rate of adverse events (AEs) following pediatric neurosurgical procedures. However, little is known regarding the morbidity of specific procedures or the association with risk factors to help guide quality improvement (QI) initiatives. The goal of this study was to describe the 30-day mortality and AE rates for pediatric neurosurgical procedures by using the American College of Surgeons (ACS) National Surgical Quality Improvement Program-Pediatrics (NSQIP-Peds) database platform. METHODS Data on 9996 pediatric neurosurgical patients were acquired from the 2012-2014 NSQIP-Peds participant user file. Neurosurgical cases were analyzed by the NSQIP-Peds targeted procedure categories, including craniotomy/craniectomy, defect repair, laminectomy, shunts, and implants. The primary outcome measure was 30-day mortality, with secondary outcomes including individual AEs, composite morbidity (all AEs excluding mortality and unplanned reoperation), surgical-site infection, and unplanned reoperation. Univariate analysis was performed between individual AEs and patient characteristics using Fischer's exact test. Associations between individual AEs and continuous variables (duration from admission to operation, work relative value unit, and operation time) were examined using the Student t-test. Patient characteristics and continuous variables associated with any AE by univariate analysis were used to develop category-specific multivariable models through backward stepwise logistic regression. RESULTS The authors analyzed 3383 craniotomy/craniectomy, 242 defect repair, 1811 laminectomy, and 4560 shunt and implant cases and found a composite overall morbidity of 30.2%, 38.8%, 10.2%, and 10.7%, respectively. Unplanned reoperation rates were highest for defect repair (29.8%). The mortality rate ranged from 0.1% to 1.2%. Preoperative ventilator dependence was a significant predictor of any AE for all procedure groups, whereas admission from outside hospital transfer was a significant predictor of any AE for all procedure groups except craniotomy/craniectomy. CONCLUSIONS This analysis of NSQIP-Peds, a large risk-adjusted national data set, confirms low perioperative mortality but high morbidity for pediatric neurosurgical procedures. These data provide a baseline understanding of current expected clinical outcomes for pediatric neurosurgical procedures, identify the need for collecting neurosurgery-specific risk factors and complications, and should support targeted QI programs and clinical management interventions to improve care of children.

Decision Neuroscience: Neuroeconomics

PubMed Central

Smith, David V.; Huettel, Scott A.

2012-01-01

Few aspects of human cognition are more personal than the choices we make. Our decisions – from the mundane to the impossibly complex – continually shape the courses of our lives. In recent years, researchers have applied the tools of neuroscience to understand the mechanisms that underlie decision making, as part of the new discipline of decision neuroscience. A primary goal of this emerging field has been to identify the processes that underlie specific decision variables, including the value of rewards, the uncertainty associated with particular outcomes, and the consequences of social interactions. Recent work suggests potential neural substrates that integrate these variables, potentially reflecting a common neural currency for value, to facilitate value comparisons. Despite the successes of decision neuroscience research for elucidating brain mechanisms, significant challenges remain. These include building new conceptual frameworks for decision making, integrating research findings across disparate techniques and species, and extending results from neuroscience to shape economic theory. To overcome these challenges, future research will likely focus on interpersonal variability in decision making, with the eventual goal of creating biologically plausible models for individual choice. PMID:22754602

Pathology in Continuous Infusion Studies in Rodents and Non-Rodents and ITO (Infusion Technology Organisation)-Recommended Protocol for Tissue Sampling and Terminology for Procedure-Related Lesions

PubMed Central

Weber, Klaus; Mowat, Vasanthi; Hartmann, Elke; Razinger, Tanja; Chevalier, Hans-Jörg; Blumbach, Kai; Green, Owen P.; Kaiser, Stefan; Corney, Stephen; Jackson, Ailsa; Casadesus, Agustin

2011-01-01

Many variables may affect the outcome of continuous infusion studies. The results largely depend on the experience of the laboratory performing these studies, the technical equipment used, the choice of blood vessels and hence the surgical technique as well the quality of pathological evaluation. The latter is of major interest due to the fact that the pathologist is not involved until necropsy in most cases, i.e. not dealing with the complicated surgical or in-life procedures of this study type. The technique of tissue sampling during necropsy and the histology processing procedures may influence the tissues presented for evaluation, hence the pathologist may be a source of misinterpretation. Therefore, ITO proposes a tissue sampling procedure and a standard nomenclature for pathological lesions for all sites and tissues in contact with the port-access and/or catheter system. PMID:22272050

Tracheobronchomegaly associated tracheomalacia: analysis by sleep study.

PubMed

Sundaram, P; Joshi, J M

2004-01-01

Tracheobronchomegaly (TBM) occasionally may progress to extensive tracheomalacia which leads to respiratory failure. Spirometry, dynamic expiratory multidetector computed tomography (CT), bronchoscopy are used to diagnose patients of suspected tracheobronchomalacia. We used the technique of night-time monitoring of respiratory variables to show the presence of respiratory abnormalities during sleep and which was corrected by applying nasal continuous positive airway pressure (CPAP). The study showed the presence of both apnoea and hypopnoeas, which were obstructive in nature with an apnoea-hypopnoea index (AHI) of 11, no snoring and associated oxygen desaturation of 75 per cent. A second overnight study with nasal continuous positive airway pressure at a critical pressure of 8 cm, the AHI decreased to 3 along with no drop in oxygen saturation. This non-invasive technique should be considered as a diagnostic tool in tracheobronchomalacia and to know the outcome of CPAP, surgical or stent therapy in this condition.

Long-distance continuous-variable quantum key distribution by controlling excess noise

NASA Astrophysics Data System (ADS)

Huang, Duan; Huang, Peng; Lin, Dakai; Zeng, Guihua

2016-01-01

Quantum cryptography founded on the laws of physics could revolutionize the way in which communication information is protected. Significant progresses in long-distance quantum key distribution based on discrete variables have led to the secure quantum communication in real-world conditions being available. However, the alternative approach implemented with continuous variables has not yet reached the secure distance beyond 100 km. Here, we overcome the previous range limitation by controlling system excess noise and report such a long distance continuous-variable quantum key distribution experiment. Our result paves the road to the large-scale secure quantum communication with continuous variables and serves as a stepping stone in the quest for quantum network.

Long-distance continuous-variable quantum key distribution by controlling excess noise.

PubMed

Huang, Duan; Huang, Peng; Lin, Dakai; Zeng, Guihua

2016-01-13

Quantum cryptography founded on the laws of physics could revolutionize the way in which communication information is protected. Significant progresses in long-distance quantum key distribution based on discrete variables have led to the secure quantum communication in real-world conditions being available. However, the alternative approach implemented with continuous variables has not yet reached the secure distance beyond 100 km. Here, we overcome the previous range limitation by controlling system excess noise and report such a long distance continuous-variable quantum key distribution experiment. Our result paves the road to the large-scale secure quantum communication with continuous variables and serves as a stepping stone in the quest for quantum network.

Long-distance continuous-variable quantum key distribution by controlling excess noise

PubMed Central

Huang, Duan; Huang, Peng; Lin, Dakai; Zeng, Guihua

2016-01-01

Quantum cryptography founded on the laws of physics could revolutionize the way in which communication information is protected. Significant progresses in long-distance quantum key distribution based on discrete variables have led to the secure quantum communication in real-world conditions being available. However, the alternative approach implemented with continuous variables has not yet reached the secure distance beyond 100 km. Here, we overcome the previous range limitation by controlling system excess noise and report such a long distance continuous-variable quantum key distribution experiment. Our result paves the road to the large-scale secure quantum communication with continuous variables and serves as a stepping stone in the quest for quantum network. PMID:26758727

Continuous tracking of the Australian National Tobacco Campaign: advertising effects on recall, recognition, cognitions, and behaviour.

PubMed

Donovan, R J; Boulter, J; Borland, R; Jalleh, G; Carter, O

2003-09-01

To relate Australian National Tobacco Campaign advertising to outcome measures such as smokers' awareness of and reaction to the campaign, and indicators of interest in smoking cessation. Continuous tracking was used to survey random cross sectional samples of the target audience via telephone interviews. Baseline measures were collected preceding each advertising phase, whereafter subjects were interviewed on a weekly basis for the entire period of each phase. Changes in outcomes could thus be inferred on a weekly basis allowing variations in advertising intensity to be monitored for effect. Three phases were evaluated variously in Melbourne, Sydney, and Adelaide. A total of 9033 subjects aged 18-40 years were interviewed. Age and sex of the sample were evenly distributed. In general, it was found that the greater the media weight, the greater the recall and recognition mediated by the message of the advertisement and the creative execution-advertisements with a clear figure ground executional format appeared more memorable than those without, and health effects advertisements were more memorable than those encouraging calls to a quitline. The relationship between various communication effects and media weight was limited by the confounding of prior activities in two of the phases. Advertisements with clear figure ground executional formats and those illustrating health effects of smoking have high memorability. Future campaigns that are continuously tracked are recommended to systematically vary media weight, flighting schedules, and advertisement type, so as to maximise information about these variables and their interactions.

Patellar denervation with electrocautery in total knee arthroplasty without patellar resurfacing: a meta-analysis.

PubMed

Cheng, Tao; Zhu, Chen; Guo, Yongyuan; Shi, Sifeng; Chen, Desheng; Zhang, Xianlong

2014-11-01

The impact of patellar denervation with electrocautery in total knee arthroplasty (TKA) on post-operative outcomes has been under debate. This study aims to conduct a meta-analysis and systematic review to compare the benefits and risks of circumpatellar electrocautery with those of non-electrocautery in primary TKAs. Comparative and randomized clinical studies were identified by conducting an electronic search of articles dated up to September 2012 in PubMed, EMBASE, Scopus, and the Cochrane databases. Six studies that focus on a total of 849 knees were analysed. A random-effects model was conducted using the inverse-variance method for continuous variables and the Mantel-Haenszel method for dichotomous variables. There was no significant difference in the incidence of anterior knee pain between the electrocautery and non-electrocautery groups. In term of patellar score and Knee Society Score, circumpatellar electrocautery improved clinical outcomes compared with non-electrocautery in TKAs. The statistical differences were in favour of the electrocautery group but have minimal clinical significance. In addition, the overall complications indicate no statistical significance between the two groups. This study shows no strong evidence either for or against electrocautery compared with non-electrocautery in TKAs. Therapeutic study (systematic review and meta-analysis), Level III.

The Use of Linear Instrumental Variables Methods in Health Services Research and Health Economics: A Cautionary Note

PubMed Central

Terza, Joseph V; Bradford, W David; Dismuke, Clara E

2008-01-01

Objective To investigate potential bias in the use of the conventional linear instrumental variables (IV) method for the estimation of causal effects in inherently nonlinear regression settings. Data Sources Smoking Supplement to the 1979 National Health Interview Survey, National Longitudinal Alcohol Epidemiologic Survey, and simulated data. Study Design Potential bias from the use of the linear IV method in nonlinear models is assessed via simulation studies and real world data analyses in two commonly encountered regression setting: (1) models with a nonnegative outcome (e.g., a count) and a continuous endogenous regressor; and (2) models with a binary outcome and a binary endogenous regressor. Principle Findings The simulation analyses show that substantial bias in the estimation of causal effects can result from applying the conventional IV method in inherently nonlinear regression settings. Moreover, the bias is not attenuated as the sample size increases. This point is further illustrated in the survey data analyses in which IV-based estimates of the relevant causal effects diverge substantially from those obtained with appropriate nonlinear estimation methods. Conclusions We offer this research as a cautionary note to those who would opt for the use of linear specifications in inherently nonlinear settings involving endogeneity. PMID:18546544

The Integration of Continuous and Discrete Latent Variable Models: Potential Problems and Promising Opportunities

ERIC Educational Resources Information Center

Bauer, Daniel J.; Curran, Patrick J.

2004-01-01

Structural equation mixture modeling (SEMM) integrates continuous and discrete latent variable models. Drawing on prior research on the relationships between continuous and discrete latent variable models, the authors identify 3 conditions that may lead to the estimation of spurious latent classes in SEMM: misspecification of the structural model,…

Donor Age-Based Analysis of Liver Transplantation Outcomes: Short- and Long-Term Outcomes Are Similar Regardless of Donor Age.

PubMed

Chapman, William C; Vachharajani, Neeta; Collins, Kelly M; Garonzik-Wang, Jackie; Park, Yikyung; Wellen, Jason R; Lin, Yiing; Shenoy, Surendra; Lowell, Jeffrey A; Doyle, M B Majella

2015-07-01

The shortage of donor organs has led to increasing use of extended criteria donors, including older donors. The upper limit of donor age that produces acceptable outcomes continues to be explored. In liver transplantation, with appropriate selection, graft survival and patient outcomes would be comparable regardless of age. We performed a retrospective analysis of 1,036 adult orthotopic liver transplantations (OLT) from a prospectively maintained database performed between January 1, 2000 and December 31, 2013. The study focus group was liver transplantations performed using grafts from older (older than 60 years) deceased donors. Deceased donor liver transplantations done during the same time period using grafts from younger donors (younger than 60 years) were analyzed for comparison. Both groups were further divided based on recipient age (less than 60 years and 60 years or older). Donor age was the primary variable. Recipient variables included were demographics, indication for transplantation, Model for End-Stage Liver Disease (MELD), graft survival, and patient survival. Operative details and postoperative complications were analyzed. Patient demographics and perioperative details were similar between groups. Patient and graft survival rates were similar in the 4 groups. Rates of rejection (p = 0.07), bile leak (p = 0.17), and hepatic artery thrombosis were comparable across all groups (p = 0.84). Hepatitis C virus recurrence was similar across all groups (p = 0.10). Thirty-one young recipients (less than 60 years) received grafts from donors aged 70 or older. Their survival and other complication rates were comparable to those in the young donor to young recipient group. Comparable outcomes in graft and patient survivals were achieved using older donors (60 years or more), regardless of recipient age, without increased rate of complications. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

The influence of age at onset and duration of illness on long-term outcome in patients with obsessive-compulsive disorder: a report from the International College of Obsessive Compulsive Spectrum Disorders (ICOCS).

PubMed

Dell'Osso, Bernardo; Benatti, Beatrice; Buoli, Massimiliano; Altamura, A Carlo; Marazziti, Donatella; Hollander, Eric; Fineberg, Naomi; Stein, Dan J; Pallanti, Stefano; Nicolini, Humberto; Van Ameringen, Michael; Lochner, Christine; Hranov, Georgi; Karamustafalioglu, Oguz; Hranov, Luchezar; Menchon, Jose M; Zohar, Joseph

2013-08-01

Several studies reported a negative effect of early onset and long duration of illness on long-term outcome in psychiatric disorders, including Obsessive-Compulsive Disorder (OCD). OCD is a prevalent, comorbid and disabling condition, associated with reduced quality of life and overall well-being for affected patients and related caregivers. The present multicenter naturalistic study sought to assess the influence of early onset and duration of illness on long-term outcome in a sample of 376 OCD out-patients worldwide, as part of the "International College of Obsessive-Compulsive Spectrum Disorders" (ICOCS) network. Binary logistic regressions were performed with age at the onset and duration of illness, as continuous independent variables, on a series of different outcome dependent variables, including lifetime number of hospitalizations and suicide attempts, poly-therapy and psychiatric comorbidity. Correlations in terms of disability (SDS) were analyzed as well. Results showed that a longer duration of illness (but not earlier age of onset) was associated with hospitalization (odds ratio=1.03, p=0.01), earlier age at onset with CBT (odds ratio=0.94, p<0.001) and both a later age at onset (odds ratio=1.05, p=0.02) and a shorter duration of illness (odds ratio=0.93, p=0.02) with panic disorder comorbidity. In addition, earlier age at onset inversely correlated with higher social disability (r=-0.12, p=0.048) and longer duration of illness directly correlated with higher disability in work, social and family life (r=0.14, p=0.017; r=0.13, p=0.035; r=0.14, p=0.02). The findings from the present large, multicenter study indicate early onset and long duration of illness as overall negative predictors of long-term outcome in OCD. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

Short-term outcomes of community-based adolescent weight management: The Loozit® Study

PubMed Central

2011-01-01

Background The Loozit® Study is a randomised controlled trial investigating extended support in a 24 month community-based weight management program for overweight to moderately obese, but otherwise healthy, 13 to 16 year olds. Methods This pre-post study examines the two month outcomes of the initial Loozit® group intervention received by both study arms. Adolescents (n = 151; 48% male) and their parents separately attended seven weekly group sessions focused on lifestyle modification. At baseline and two months, adolescents' anthropometry, blood pressure, and fasted blood sample were assessed. Primary outcomes were two month changes in body mass index (BMI) z-score and waist-to-height-ratio (WHtR). Secondary outcomes included changes in metabolic profile, self-reported dietary intake/patterns, physical and sedentary activities, psychological characteristics and social status. Changes in outcome measures were assessed using paired samples t-tests for continuous variables or McNemar's test for dichotomous categorical variables. Results Of the 151 adolescents who enrolled, 130 (86%) completed the two month program. Among these 130 adolescents (47% male), there was a statistically significant (P < 0.01) reduction in mean [95% CI] BMI (0.27 kg/m2 [0.41, 0.13]), BMI z-score (0.05 [0.06, 0.03]), WHtR (0.02 [0.03, 0.01]), total cholesterol (0.14 mmol/L [0.24, 0.05]) and low-density lipoprotein cholesterol (0.12 mmol/L [0.21, 0.04]). There were improvements in all psychological measures, the majority of the dietary intake measures, and some physical activities (P < 0.05). Time spent watching TV and participating in non-screen sedentary activities decreased (P < 0.05). Conclusions The Loozit® program may be a promising option for stabilizing overweight and improving various metabolic factors, psychological functioning and lifestyle behaviors in overweight adolescents in a community setting. Trial registration Australian New Zealand Clinical Trials Registry ACTRNO12606000175572 PMID:21303505

Association of chronic kidney disease with abnormal cardiac mechanics and adverse outcomes in patients with heart failure and preserved ejection fraction.

PubMed

Unger, Erin D; Dubin, Ruth F; Deo, Rajat; Daruwalla, Vistasp; Friedman, Julie L; Medina, Crystal; Beussink, Lauren; Freed, Benjamin H; Shah, Sanjiv J

2016-01-01

Chronic kidney disease (CKD) is associated with worse outcomes in heart failure with preserved ejection fraction (HFpEF). Whether this association is due the effect of CKD on intrinsic abnormalities in cardiac function is unknown. We hypothesized that CKD is independently associated with worse cardiac mechanics in HFpEF. We prospectively studied 299 patients enrolled in the Northwestern University HFpEF Program. Using the creatinine-based CKD-Epi equation to calculate estimated glomerular filtration rate (eGFR), study participants were analysed by CKD status (using eGFR <60 mL/min/1.73 m(2) to denote CKD). Indices of cardiac mechanics (longitudinal strain parameters) were measured using speckle-tracking echocardiography. Using multivariable-adjusted linear and Cox regression analyses, we determined the association between CKD and echocardiographic parameters and clinical outcomes (cardiovascular hospitalization or death). Of 299 study participants, 48% had CKD. CKD (dichotomous variable) and reduced eGFR (continuous variable) were both associated with worse cardiac mechanics indices including left atrial (LA) reservoir strain, LV longitudinal strain, and right ventricular free wall strain even after adjusting for potential confounders, including co-morbidities, EF, and volume status. For example, for each 1-SD decrease in eGFR, LA reservoir strain was 3.52% units lower (P < 0.0001) after multivariable adjustment. Reduced eGFR was also associated with worse outcomes [adjusted hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.01-1.61 per 1-SD decrease in eGFR; P = 0.039]. The association was attenuated after adjustment for indices of cardiac mechanics (P = 0.064). In HFpEF, CKD is independently associated with worse cardiac mechanics, which may explain why HFpEF patients with CKD have worse outcomes. NCT01030991. © 2015 The Authors European Journal of Heart Failure © 2015 European Society of Cardiology.

A Pharmacist Telephone Intervention to Identify Adherence Barriers and Improve Adherence Among Nonadherent Patients with Comorbid Hypertension and Diabetes in a Medicare Advantage Plan.

PubMed

Abughosh, Susan M; Wang, Xin; Serna, Omar; Henges, Chris; Masilamani, Santhi; Essien, Ekere James; Chung, Nancy; Fleming, Marc

2016-01-01

Patients with comorbid hypertension (HTN) and diabetes mellitus (DM) are at a high risk of developing macrovascular and microvascular complications of DM. Controlling high blood pressure can greatly reduce these complications. Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) are recommended for patients with both DM and HTN by the American Diabetes Association guidelines, and their benefit and efficacy in reducing macrovascular and microvascular complications of DM have been well documented. Poor adherence, however, remains a significant barrier to achieving full effectiveness and optimal outcomes. To examine the effect of a brief pharmacist telephone intervention in identifying adherence barriers and improving adherence to ACEI/ARB medications among nonadherent patients with comorbid HTN and DM who are enrolled in a Medicare Advantage plan. Cigna-HealthSpring's medical claims data was used to identify patients with HTN and DM diagnoses by using ICD-9-CM codes 401 and 250, and at least 2 fills for ACEIs or ARBs between January 2013 and October 2013. Patients who failed to refill their medication for more than 1 day and had a proportion of days covered (PDC) < 0.8 were considered nonadherent and were contacted by a pharmacist by phone to identify adherence barriers. Two outcome variables were evaluated: The first was adherence to ACEIs/ARBs, defined as PDC during the 6 months following the phone call intervention. The second outcome variable was a categorical outcome of discontinuation versus continuation. Discontinuation was defined as not using ACEIs/ARBs during the 6-month post-intervention period. Patients who disenrolled from the plan in 2014 or were switched to another medication commonly used for treating DM and HTN were excluded from further analysis. Descriptive statistics were conducted to assess the frequency distribution of sample demographic characteristics at baseline. Multiple linear regression was conducted to assess the intervention effect on adherence during the 6 months post-intervention using the first outcome of post-intervention PDC, adjusting for baseline PDC and other covariates. Logistic regression was performed to assess the association between medication discontinuation and other baseline characteristics using the second outcome of discontinuation. Other control variables in the models included demographics (age, sex, language), physician specialty (primary care vs. specialist), health plan (low-income subsidy vs. other), Centers for Medicare & Medicaid risk score, Charlson Comorbidity Index, and number of distinct medications. In total, 186 hypertensive diabetic patients, nonadherent to ACEIs/ARBs (PDC < 0.8), were included in the study. Of the 186 patients, 87 received the pharmacist phone call intervention. Among these patients, forgetfulness (25.29%) and doctor issues, such as having difficulty scheduling appointments (16.79%), were the most commonly reported barriers. After excluding those who switched from ACEIs/ARBs to another medication, 157 patients were included in the logistic regression model. Of those, 131 had continued using ACEIs/ARBs and were included in the linear regression model. The mean (±SD) post-intervention PDC for the intervention group was 0.58 (±0.26) and for the control group 0.29 (±0.17). Intervention was a significant predictor of better adherence in the linear regression model after adjusting all the other baseline covariates (β = 0.3182, 95% CI = 0.19-0.38, P < 0.001). Other covariates were not significantly associated with better adherence. In the logistic regression model (discontinuation: 26 [yes]/131 [no]) for predicting medication discontinuation, patients who received intervention were more likely to continue using ACEIs/ARBs (OR = 3.56, 95% CI = 1.06-11.86), and those with a higher comorbidity index were less likely to continue using them (OR = 0.72, 95% CI = 0.53-0.99). The brief pharmacist telephone intervention resulted in significantly better PDCs during the 6 months following the intervention as well as lower discontinuation rates among a group of nonadherent patients with comorbid HTN and DM. The overall PDC rates in both the intervention and control groups were still lower than the recommended 80%. Improving adherence to clinically meaningful values may require more than a brief pharmacist phone call. Incorporating motivational interviewing techniques with follow-up calls to address adherence barriers may be more influential in forming sustainable behavioral change and enhancing medication adherence.

Robot-assisted partial nephrectomy: continued refinement of outcomes beyond the initial learning curve.

PubMed

Paulucci, David J; Abaza, Ronney; Eun, Daniel D; Hemal, Ashok K; Badani, Ketan K

2017-05-01

To evaluate trends in peri-operative outcomes of 250 consecutive cases beyond the initial learning curve (LC) of robot-assisted partial nephrectomy (RAPN) among multiple surgeons. A multi-institutional database was used to evaluate trends in patient demographics (e.g. age, gender, comorbidities), tumour characteristics (e.g. size, complexity) and peri-operative outcomes (e.g. warm ischaemia time [WIT], operating time, complications, estimated blood loss [EBL], trifecta achievement) in consecutive cases 50-300 (n = 960) from 2008 to 2016 among four experienced surgeons. Trends in outcomes were assessed using multivariable regression models adjusted for demographic and tumour-specific variables. Outcomes for cases 50-99 were compared with those for cases 250-300. In the study period RAPN was increasingly performed in patients with larger tumours (β = 0.001, P = 0.048), hypertension (odds ratio [OR] 1.003; P = 0.008) diabetes (OR 1.003; P = 0.025) and previous abdominal surgery (OR 1.003; P = 0.006). Surgeon experience was associated with more trifecta achievement (OR 1.006; P < 0.001), shorter WIT (β = -0.036, P < 0.001), less EBL (β = -0.154, P = 0.009), fewer blood transfusions (OR 0.989, P = 0.024) and a reduced length of hospital stay (β = -0.002, P = 0.002), but not with operating time (P = 0.243), complications (P = 0.587) or surgical margin status (P = 0.102). Tumour size and WIT in cases 50-99 vs 250-300 were 2.7 vs 3.2 cm (P = 0.001) and 21.4 vs 16.2 min (P < 0.001), respectively. Refinement of RAPN outcomes, concomitant with the treatment of a patient population with larger tumours and more comorbidities, occurs after the initial LC is reached. Although RAPN can consistently be performed safely with acceptable outcomes after a small number of cases, improvement in trifecta achievement, WIT, EBL, blood transfusions and a shorter hospitalization continues to occur up to 300 procedures. © 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.

Admission white blood cell count predicts short-term clinical outcomes in patients with uncomplicated Stanford type B acute aortic dissection.

PubMed

Chen, Zhao-Ran; Huang, Bi; Lu, Hai-Song; Zhao, Zhen-Hua; Hui, Ru-Tai; Yang, Yan-Min; Fan, Xiao-Han

2017-01-01

Inflammation has been shown to be related with acute aortic dissection (AAD). The present study aimed to evaluate the association of white blood cell counts (WBCc) on admission with both in-hospital and long-term all-cause mortality in patients with uncomplicated Stanford type B AAD. From 2008 to 2010, a total of 377 consecutive patients with uncomplicated type B AAD were enrolled and then followed up. Clinical data and WBCc on admission were collected. The primary end points were in-hospital death and long-term all-cause death. The in-hospital death rate was 4.2%, and the long-term all-cause mortality rate was 6.9% during a median follow-up of 18.9 months. WBCc on admission was identified as a risk factor for in-hospital death by univariate Cox regression analysis as both a continuous variable and a categorical variable using a cut off of 11.0 × 10 9 cell/L (all P < 0.05). After adjusting for age, sex and other risk factors, elevated admission WBCc was still a significant predictor for in-hospital death as both a continuous variable [hazard ratio (HR): 1.052, 95% CI: 1.024-1.336, P = 0.002] and a categorical variable using a cut off of 11.0 × 10 9 cell/L (HR: 2.056, 95% CI: 1.673-5.253, P = 0.034). No relationship was observed between WBCc on admission and long-term all-cause death. Our results indicate that elevated WBCc upon admission might be used as a predictor for increased risk of in-hospital death in uncomplicated type B AAD. There might be no predictive value of WBCc for the long-term survival of type B AAD.

Marital Status, Marital Quality, and Heart Rate Variability in the MIDUS Cohort

PubMed Central

Donoho, Carrie J.; Seeman, Teresa E.; Sloan, Richard P.; Crimmins, Eileen M.

2015-01-01

Previous research has shown marital status and marital quality are consistent predictors of health outcomes, including cardiovascular disease and mortality. To better understand the relationship between marital status, marital quality, and cardiovascular health, we examined how marital status and marital quality were associated with an early indicator of deteriorating cardiovascular health, high-frequency heart rate variability (HF-HRV). This study uses data from the National Survey of Midlife in the United States (MIDUS) Biomarker Sub-study (n = 907) to examine differences in HF-HRV by traditional marital status categories (married, divorced, widowed, and never married), as well as further differentiating between the continuously married and remarried. In addition, links were also examined between HF-HRV and changes in marital quality (marital satisfaction, support, strain), among individuals in long-term marriages. No significant differences in HF-HRV were observed between married persons and those widowed, divorced, and never married. However, continuously married individuals had higher HF-HRV than remarried adults. Increases in marital satisfaction and support over 10 years were associated with higher HF-HRV, while increased marital strain over 10 years was associated with lower HFHRV. Higher HF-HRV among the continuously married compared to the remarried suggests previous marital disruptions may have lasting effects on cardiovascular health, or that there may be other differences between the remarried versus those who remain married to the same person. Associations between marital quality and HF-HRV suggest variations in the quality of one’s marriage may affect cardiovascular health. PMID:25844496

Violation of Bell's Inequality Using Continuous Variable Measurements

NASA Astrophysics Data System (ADS)

Thearle, Oliver; Janousek, Jiri; Armstrong, Seiji; Hosseini, Sara; Schünemann Mraz, Melanie; Assad, Syed; Symul, Thomas; James, Matthew R.; Huntington, Elanor; Ralph, Timothy C.; Lam, Ping Koy

2018-01-01

A Bell inequality is a fundamental test to rule out local hidden variable model descriptions of correlations between two physically separated systems. There have been a number of experiments in which a Bell inequality has been violated using discrete-variable systems. We demonstrate a violation of Bell's inequality using continuous variable quadrature measurements. By creating a four-mode entangled state with homodyne detection, we recorded a clear violation with a Bell value of B =2.31 ±0.02 . This opens new possibilities for using continuous variable states for device independent quantum protocols.

Alkaline phosphatase for treatment of sepsis-induced acute kidney injury: a prospective randomized double-blind placebo-controlled trial

PubMed Central

2012-01-01

Introduction To evaluate whether alkaline phosphatase (AP) treatment improves renal function in sepsis-induced acute kidney injury (AKI), a prospective, double-blind, randomized, placebo-controlled study in critically ill patients with severe sepsis or septic shock with evidence of AKI was performed. Methods Thirty-six adult patients with severe sepsis or septic shock according to Systemic Inflammatory Response Syndrome criteria and renal injury defined according to the AKI Network criteria were included. Dialysis intervention was standardized according to Acute Dialysis Quality Initiative consensus. Intravenous infusion of alkaline phosphatase (bolus injection of 67.5 U/kg body weight followed by continuous infusion of 132.5 U/kg/24 h for 48 hours, or placebo) starting within 48 hours of AKI onset and followed up to 28 days post-treatment. The primary outcome variable was progress in renal function variables (endogenous creatinine clearance, requirement and duration of renal replacement therapy, RRT) after 28 days. The secondary outcome variables included changes in circulating inflammatory mediators, urinary excretion of biomarkers of tubular injury, and safety. Results There was a significant (P = 0.02) difference in favor of AP treatment relative to controls for the primary outcome variable. Individual renal parameters showed that endogenous creatinine clearance (baseline to Day 28) was significantly higher in the treated group relative to placebo (from 50 ± 27 to 108 ± 73 mL/minute (mean ± SEM) for the AP group; and from 40 ± 37 to 65 ± 30 mL/minute for placebo; P = 0.01). Reductions in RRT requirement and duration did not reach significance. The results in renal parameters were supported by significantly more pronounced reductions in the systemic markers C-reactive protein, Interleukin-6, LPS-binding protein and in the urinary excretion of Kidney Injury Molecule-1 and Interleukin-18 in AP-treated patients relative to placebo. The Drug Safety Monitoring Board did not raise any issues throughout the trial. Conclusions The improvements in renal function suggest alkaline phosphatase is a promising new treatment for patients with severe sepsis or septic shock with AKI. Trial Registration www.clinicaltrials.gov: NCTNCT00511186 PMID:22269279

Combining clinical variables to optimize prediction of antidepressant treatment outcomes.

PubMed

Iniesta, Raquel; Malki, Karim; Maier, Wolfgang; Rietschel, Marcella; Mors, Ole; Hauser, Joanna; Henigsberg, Neven; Dernovsek, Mojca Zvezdana; Souery, Daniel; Stahl, Daniel; Dobson, Richard; Aitchison, Katherine J; Farmer, Anne; Lewis, Cathryn M; McGuffin, Peter; Uher, Rudolf

2016-07-01

The outcome of treatment with antidepressants varies markedly across people with the same diagnosis. A clinically significant prediction of outcomes could spare the frustration of trial and error approach and improve the outcomes of major depressive disorder through individualized treatment selection. It is likely that a combination of multiple predictors is needed to achieve such prediction. We used elastic net regularized regression to optimize prediction of symptom improvement and remission during treatment with escitalopram or nortriptyline and to identify contributing predictors from a range of demographic and clinical variables in 793 adults with major depressive disorder. A combination of demographic and clinical variables, with strong contributions from symptoms of depressed mood, reduced interest, decreased activity, indecisiveness, pessimism and anxiety significantly predicted treatment outcomes, explaining 5-10% of variance in symptom improvement with escitalopram. Similar combinations of variables predicted remission with area under the curve 0.72, explaining approximately 15% of variance (pseudo R(2)) in who achieves remission, with strong contributions from body mass index, appetite, interest-activity symptom dimension and anxious-somatizing depression subtype. Escitalopram-specific outcome prediction was more accurate than generic outcome prediction, and reached effect sizes that were near or above a previously established benchmark for clinical significance. Outcome prediction on the nortriptyline arm did not significantly differ from chance. These results suggest that easily obtained demographic and clinical variables can predict therapeutic response to escitalopram with clinically meaningful accuracy, suggesting a potential for individualized prescription of this antidepressant drug. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Plant immunity: towards an integrated view of plant-pathogen interactions.

PubMed

Dodds, Peter N; Rathjen, John P

2010-08-01

Plants are engaged in a continuous co-evolutionary struggle for dominance with their pathogens. The outcomes of these interactions are of particular importance to human activities, as they can have dramatic effects on agricultural systems. The recent convergence of molecular studies of plant immunity and pathogen infection strategies is revealing an integrated picture of the plant-pathogen interaction from the perspective of both organisms. Plants have an amazing capacity to recognize pathogens through strategies involving both conserved and variable pathogen elicitors, and pathogens manipulate the defence response through secretion of virulence effector molecules. These insights suggest novel biotechnological approaches to crop protection.

Letter to editor: Blood pressure, hypertension and lead exposure.

PubMed

Yang, Wen-Yi; Staessen, Jan A

2018-02-19

A significant association of office diastolic blood pressure with low-level blood lead exposure was reported in a Brazilian adult population. However, caution should be taken to interpret these results. The multivariable-adjusted association with blood pressure was positive for diastolic blood pressure, but inverse for systolic blood pressure. The association sizes were infinitesimal without clinical relevance. The outcome measures, i.e. blood pressure and the prevalence of hypertension were analysed across categories of the blood lead distribution - not in relation to blood lead as continuous variable. Blood pressure was the average of two oscillometric office readings, whereas ambulatory monitoring is the state-of-the-art.

Civil Commitment for Opioid and Other Substance Use Disorders: Does It Work?

PubMed

Jain, Abhishek; Christopher, Paul; Appelbaum, Paul S

2018-04-01

Many states are turning to civil commitment for substance use disorders as a potential solution to address rising rates of overdose deaths. Civil commitment allows family members or others to seek court-ordered involuntary treatment for a substance-abusing person. In contrast to mandatory treatment ordered by drug courts, civil commitment does not require involvement with the criminal justice system. Although these laws are understandably appealing, statutes and their implementation are highly variable, ethical concerns about deprivation of liberty continue to be raised, and outcome data are limited and often not generalizable. Above all, more studies are needed to determine effectiveness.

CLINICAL outcomes and loss to follow-up among people living with HIV participating in the NAMWEZA intervention in Dar es Salaam, Tanzania: a prospective cohort study.

PubMed

Siril, Hellen N; Kaaya, Sylvia F; Smith Fawzi, Mary Kay; Mtisi, Expeditho; Somba, Magreat; Kilewo, Japheth; Mugusi, Ferdinand; Minja, Anna; Kaale, Anna; Todd, Jim

2017-03-28

Psychosocial factors have been linked with loss to follow-up (LTFU) and clinical outcomes among people living with HIV (PLH), however little is known about the effect of psychosocial support on LTFU among PLH in treatment and care. The purpose of this study was to explore the effect of NAMWEZA ("Yes, together we can") friends' psychosocial support intervention on clinical outcomes and LTFU among PLH. NAMWEZA is based on a novel program using "appreciative inquiry", positive psychology approaches to empower, promote positive attitudes and foster hope. PLH participating in the NAMWEZA intervention in HIV care clinics in Dar es Salaam Tanzania were compared with non-exposed PLH obtained from facilities that routinely collect clinical information and both followed longitudinally for 24 months. Baseline sociodemographic, clinical measures (CD4 cell count, hemoglobin (HGB), weight), and LTFU measures were collected. Chi square, Fisher's exact tests, and t-tests were used to compare the frequencies for categorical variables and the means of continuous variables from the intervention and the comparison groups to identify variables that were significantly different across the two groups. Random effects models were performed to examine the bivariate associations between the intervention status and clinical outcomes. At the end of 24 months of follow-up mean CD4 count and HGB levels increased significantly in both intervention and comparison groups (p = 0.009 and p < 0.0001, respectively). Weight increased significantly only in the intervention group (p = 0.003). Cumulative LTFU was three times higher in the comparison compared to the intervention (p < 0.001) group. Having a low CD4 count, extremes of weight, low HGB, younger age, and male gender were significantly associated with LTFU among the unexposed group, while being on ART for duration of 12 months or more was protective against LTFU in those intervened. Among PLH on ART, exposed or not exposed to NAMWEZA intervention, clinical care outcomes improved over time. LTFU was much higher in the comparison group with factors commonly known to predict LTFU only apparent in the comparison group. NAMWEZA could be a promising peer-facilitated model to reduce LTFU among PLH in care that can be integrated in ART services; however, more research is needed to evaluate its longer term effects.

Discrete-continuous variable structural synthesis using dual methods

NASA Technical Reports Server (NTRS)

Schmit, L. A.; Fleury, C.

1980-01-01

Approximation concepts and dual methods are extended to solve structural synthesis problems involving a mix of discrete and continuous sizing type of design variables. Pure discrete and pure continuous variable problems can be handled as special cases. The basic mathematical programming statement of the structural synthesis problem is converted into a sequence of explicit approximate primal problems of separable form. These problems are solved by constructing continuous explicit dual functions, which are maximized subject to simple nonnegativity constraints on the dual variables. A newly devised gradient projection type of algorithm called DUAL 1, which includes special features for handling dual function gradient discontinuities that arise from the discrete primal variables, is used to find the solution of each dual problem. Computational implementation is accomplished by incorporating the DUAL 1 algorithm into the ACCESS 3 program as a new optimizer option. The power of the method set forth is demonstrated by presenting numerical results for several example problems, including a pure discrete variable treatment of a metallic swept wing and a mixed discrete-continuous variable solution for a thin delta wing with fiber composite skins.

Multiple Measures of Outcome in Assessing a Prison-Based Drug Treatment Program

ERIC Educational Resources Information Center

Prendergast, Michael L.; Hall, Elizabeth A.; Wexler, Harry K.

2003-01-01

Evaluations of prison-based drug treatment programs typically focus on one or two dichotomous outcome variables related to recidivism. In contrast, this paper uses multiple measures of outcomes related to crime and drug use to examine the impact of prison treatment. Crime variables included self-report data of time to first illegal activity,…

Variability in Outcome for Children with an ASD Diagnosis at Age 2

ERIC Educational Resources Information Center

Turner, Lauren M.; Stone, Wendy L.

2007-01-01

Background: Few studies have examined the variability in outcomes of children diagnosed with autism spectrum disorder (ASD) at age 2. Research is needed to understand the children whose symptoms--or diagnoses--change over time. The objectives of this study were to examine the behavioral and diagnostic outcomes of a carefully defined sample of…

Absolute spike frequency as a predictor of surgical outcome in temporal lobe epilepsy.

PubMed

Ngo, Ly; Sperling, Michael R; Skidmore, Christopher; Mintzer, Scott; Nei, Maromi

2017-04-01

Frequent interictal epileptiform abnormalities may correlate with poor prognosis after temporal lobe resection for refractory epilepsy. To date, studies have focused on limited resections such as selective amygdalohippocampectomy and apical temporal lobectomy without hippocampectomy. However, it is unclear whether the frequency of spikes predicts outcome after standard anterior temporal lobectomy. Preoperative scalp video-EEG monitoring data from patients who subsequently underwent anterior temporal lobectomy over a three year period and were followed for at least one year were reviewed for the frequency of interictal epileptiform abnormalities. Surgical outcome for those patients with frequent spikes (>60/h) was compared with those with less frequent spikes. Additionally, spike frequency was evaluated as a continuous variable and correlated with outcome to determine if increased spike frequency correlated with worse outcome, as assessed by modified Engel Class outcome. Forty-seven patients (18 men, 29 women; mean age 40 years at surgery) were included. Forty-six patients had standard anterior temporal lobectomy (24 right, 22 left) and one had a modified left temporal lobectomy. There was no significant difference in seizure outcome between those with frequent (57% Class I) vs. those with less frequent (58% Class I) spikes. Increased spike frequency did not correlate with worse outcome. Greater than 20 complex partial seizures/month and generalized tonic-clonic seizures within one year of surgery correlated with worse outcome. This study suggests that absolute spike frequency does not predict seizure outcome after anterior temporal lobectomy unlike in selective procedures, and should not be used as a prognostic factor in this population. Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Patient-Reported Outcomes of Aesthetics and Satisfaction in Immediate Breast Reconstruction After Nipple-Sparing Mastectomy With Implants and Fat Grafting.

PubMed

Qureshi, Ali A; Odom, Elizabeth B; Parikh, Rajiv P; Myckatyn, Terence M; Tenenbaum, Marissa M

2017-10-01

Direct-to-implant (DTI) and tissue expander/implant (TE/I) reconstructions are the most common implant-based reconstructions after nipple-sparing mastectomy (NSM). However, there are little data beyond complication rates comparing these options. Fat grafting has emerged as an adjunct in NSM reconstructions to improve aesthetic results; however, its impact on patient perceptions of aesthetic outcomes remain unknown. To improve patient-centered care, aesthetic outcomes must be considered from the patients' perspective. To evaluate patient-reported outcomes of aesthetic satisfaction and quality of life in patients undergoing immediate DTI vs TE/I reconstruction after NSM and to assess the role of fat grafting on these outcomes. This is a prospective cohort study comparing NSM patients undergoing DTI or TE/I reconstruction. Patient-reported outcomes were evaluated using the BREAST-Q. Continuous and categorical variables were analyzed using t test and Fisher's exact test, respectively. Fifty-nine patients underwent 113 reconstructions with either DTI (n = 41) or TE/I (n = 18). Mean follow up was 12.1 months. DTI and TE/I patients had comparable satisfaction with outcome, though TE/I patients had significantly larger final implant sizes. TE/I who underwent fat grafting also had significantly higher satisfaction with outcome and psychosocial wellbeing. Patient-reported outcomes are comparable between DTI and TE/I reconstructions after NSM. In order for TE/I patients to achieve a similar level of satisfaction, they may require a larger final implant and additional operations compared to DTI patients. Additionally, fat grafting improves overall satisfaction. TE/I patients may have different aesthetic expectations than DTI patients, emphasizing patient-centered discussions are essential to optimizing outcomes after NSM. 3. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Insecticide treated bednet strategy in rural settings: can we exploit women's decision making power?

PubMed

Tilak, Rina; Tilak, V W; Bhalwar, R

2007-01-01

Use of insecticide treated bednets in prevention of malaria is a widely propagated global strategy, however, its use has been reported to be influenced and limited by many variables especially gender bias. A cross sectional field epidemiological study was conducted in a rural setting with two outcome variables, 'Bednet use'(primary outcome variable) and 'Women's Decision Making Power' which were studied in reference to various predictor variables. Analysis reveals a significant effect on the primary outcome variable 'Bednet use' of the predictor variables- age, occupation, bednet purchase decision, women's decision making power, husband's education and knowledge about malaria and its prevention. The study recommends IEC on treated bednets to be disseminated through TV targeting the elderly women who have better decision making power and mobilizing younger women who were found to prefer bednets for prevention of mosquito bites for optimizing the use of treated bednets in similar settings.

Patterns of Therapist Variability: Therapist Effects and the Contribution of Patient Severity and Risk

ERIC Educational Resources Information Center

Saxon, David; Barkham, Michael

2012-01-01

Objective: To investigate the size of therapist effects using multilevel modeling (MLM), to compare the outcomes of therapists identified as above and below average, and to consider how key variables--in particular patient severity and risk and therapist caseload--contribute to therapist variability and outcomes. Method: We used a large…

Relationships between Admission Variables and Outcome Variables in a Special Education Graduate Program

ERIC Educational Resources Information Center

LaFave, Matthew

2012-01-01

The need for well-prepared special education teachers has made it important to examine how to best select candidates for special education teacher education programs, or at least to determine which, if any, admission variables relate to program outcome measures. This study used archival data from 148 students to investigate the relationships among…

The Impact of Continuous Medicaid Enrollment on Diagnosis, Treatment, and Survival in Six Surgical Cancers

PubMed Central

Dawes, Aaron J; Louie, Rachel; Nguyen, David K; Maggard-Gibbons, Melinda; Parikh, Punam; Ettner, Susan L; Ko, Clifford Y; Zingmond, David S

2014-01-01

Objective To examine the effect of Medicaid enrollment on the diagnosis, treatment, and survival of six surgically relevant cancers among poor and underserved Californians. Data Sources California Cancer Registry (CCR), California's Patient Discharge Database (PDD), and state Medicaid enrollment files between 2002 and 2008. Study Design We linked clinical and administrative records to differentiate patients continuously enrolled in Medicaid from those receiving coverage at the time of their cancer diagnosis. We developed multivariate logistic regression models to predict death within 1 year for each cancer after controlling for sociodemographic and clinical variables. Data Collection/Extraction Methods All incident cases of six cancers (colon, esophageal, lung, pancreas, stomach, and ovarian) were identified from CCR. CCR records were linked to hospitalizations (PDD) and monthly Medicaid enrollment. Principal Findings Continuous enrollment in Medicaid for at least 6 months prior to diagnosis improves survival in three surgically relevant cancers. Discontinuous Medicaid patients have higher stage tumors, undergo fewer definitive operations, and are more likely to die even after risk adjustment. Conclusions Expansion of continuous insurance coverage under the Affordable Care Act is likely to improve both access and clinical outcomes for cancer patients in California. PMID:25256223

Information Processing from Infancy to 11 Years: Continuities and Prediction of IQ

PubMed Central

Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.; Van Rossem, Ronan

2012-01-01

This study provides the first direct evidence of cognitive continuity for multiple specific information processing abilities from infancy and toddlerhood to pre-adolescence, and provides support for the view that infant abilities and form the basis of later childhood abilities. Data from a large sample of children (N = 131) were obtained at five different time points (7, 12, 24, 36 months, and 11 years) for a large battery of tasks representing four cognitive domains (attention, processing speed, memory, and representational competence). Structural equation models of continuity were assessed for each domain, in which it was assumed that infant abilities → toddler abilities → 11-year abilities. Abilities at each age were represented by latent variables, which minimize task-specific variance and measurement error. The model for each domain fit the data. Moreover, abilities from the three age periods predicted global outcome, with infant, toddler, and contemporaneous 11-year measures, respectively, accounting for 12.3%, 18.5%, and 45.2% of the variance in 11-year IQ. These findings strengthen contentions that specific cognitive abilities that can be identified in infancy show long-term continuity and contribute importantly to later cognitive competence. PMID:23162179

Psychotherapy integration under scrutiny: investigating the impact of integrating emotion-focused components into a CBT-based approach: a study protocol of a randomized controlled trial.

PubMed

Babl, Anna; Grosse Holtforth, Martin; Heer, Sara; Lin, Mu; Stähli, Annabarbara; Holstein, Dominique; Belz, Martina; Egenolf, Yvonne; Frischknecht, Eveline; Ramseyer, Fabian; Regli, Daniel; Schmied, Emma; Flückiger, Christoph; Brodbeck, Jeannette; Berger, Thomas; Caspar, Franz

2016-11-24

This currently recruiting randomized controlled trial investigates the effects of integrating components of Emotion-Focused Therapy (EFT) into Psychological Therapy (PT), an integrative form of cognitive-behavioral therapy in a manner that is directly mirroring common integrative practice in the sense of assimilative integration. Aims of the study are to understand how both, an existing therapy approach as well as the elements to be integrated, are affected by the integration and to clarify the role of emotional processing as a mediator of therapy outcome. A total of 130 adults with a diagnosed unipolar depressive, anxiety or adjustment disorder (seeking treatment at a psychotherapy outpatient clinic) are randomized to either treatment as usual (PT) with integrated emotion-focused components (TAU + EFT) or PT (TAU). Primary outcome variables are psychopathology and symptom severity at the end of therapy and at follow up; secondary outcome variables are interpersonal problems, psychological wellbeing, quality of life, attainment of individual therapy goals, and emotional competency. Furthermore, process variables such as the quality of the therapeutic relationship are studied as well as aptitude-treatment interactions. Variables are assessed at baseline, after 8 and 16 sessions, at the end of therapy, after 25 ± 3 sessions, and at 6, 12 and 36 month follow-up. Underlying mechanisms of change are investigated. Statistical analyses will be conducted using the appropriate multilevel approaches, mainly two-level regression and growth analysis. The results of this study will indicate whether the integration of emotion-focused elements into treatment as usual increases the effectiveness of Psychological Therapy. If advantages are found, which may be limited to particular variables or subgroups of patients, recommendations for a systematic integration, and caveats if also disadvantages are detected, can be formulated. On a more abstract level, a cognitive behavioral (represented by PT) and humanistic/experiential (represented by EFT) approach will be integrated. It must be emphasized that mimicking common practice in the development and continued education of psychotherapists, EFT is not integrated as a whole, but only elements of EFT that are considered particularly important, and can be trained in an 8-day training plus supervision of therapies. ClinicalTrials.gov, NCT02822443 , 22 June 2016, retrospectively registered.

Influential input classification in probabilistic multimedia models

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

Maddalena, Randy L.; McKone, Thomas E.; Hsieh, Dennis P.H.

1999-05-01

Monte Carlo analysis is a statistical simulation method that is often used to assess and quantify the outcome variance in complex environmental fate and effects models. Total outcome variance of these models is a function of (1) the uncertainty and/or variability associated with each model input and (2) the sensitivity of the model outcome to changes in the inputs. To propagate variance through a model using Monte Carlo techniques, each variable must be assigned a probability distribution. The validity of these distributions directly influences the accuracy and reliability of the model outcome. To efficiently allocate resources for constructing distributions onemore » should first identify the most influential set of variables in the model. Although existing sensitivity and uncertainty analysis methods can provide a relative ranking of the importance of model inputs, they fail to identify the minimum set of stochastic inputs necessary to sufficiently characterize the outcome variance. In this paper, we describe and demonstrate a novel sensitivity/uncertainty analysis method for assessing the importance of each variable in a multimedia environmental fate model. Our analyses show that for a given scenario, a relatively small number of input variables influence the central tendency of the model and an even smaller set determines the shape of the outcome distribution. For each input, the level of influence depends on the scenario under consideration. This information is useful for developing site specific models and improving our understanding of the processes that have the greatest influence on the variance in outcomes from multimedia models.« less

Predicting Well-being Longitudinally for Mothers Rearing Offspring with Intellectual and Developmental Disabilities

PubMed Central

Grein, Katherine A.; Glidden, Laraine Masters

2014-01-01

Background Well-being outcomes for parents of children with intellectual and developmental disabilities (IDD) may vary from positive to negative at different times and for different measures of well-being. Predicting and explaining this variability has been a major focus of family research for reasons that have both theoretical and applied implications. Methods The current study used data from a 23-year longitudinal investigation of adoptive and birth parents of children with IDD to determine which early child, mother, and family characteristics would predict the variance in maternal outcomes 20 years after their original measurement. Using hierarchical regression analyses, we tested the predictive power of variables measured when children were 7 years old on outcomes of maternal well-being when children were 26 years old. Outcome variables included maternal self-report measures of depression and well–being. Results Final models of well-being accounted for 20% to 34% of variance. For most outcomes, Family Accord and/or the personality variable of Neuroticism (emotional stability/instability) were significant predictors, but some variables demonstrated a different pattern. Conclusions These findings confirm that 1) Characteristics of the child, mother, and family during childhood can predict outcomes of maternal well-being 20 years later; and 2) Different predictor-outcome relationships can vary substantially, highlighting the importance of using multiple measures to gain a more comprehensive understanding of maternal well-being. These results have implications for refining prognoses for parents and for tailoring service delivery to individual child, parent, and family characteristics. PMID:25185956

Implementation of a Cardiogenic Shock Team and Clinical Outcomes (INOVA-SHOCK Registry): Observational and Retrospective Study.

PubMed

Tehrani, Behnam; Truesdell, Alexander; Singh, Ramesh; Murphy, Charles; Saulino, Patricia

2018-06-28

The development and implementation of a Cardiogenic Shock initiative focused on increased disease awareness, early multidisciplinary team activation, rapid initiation of mechanical circulatory support, and hemodynamic-guided management and improvement of outcomes in cardiogenic shock. The objectives of this study are (1) to collect retrospective clinical outcomes for acute decompensated heart failure cardiogenic shock and acute myocardial infarction cardiogenic shock, and compare current versus historical survival rates and clinical outcomes; (2) to evaluate Inova Heart and Vascular Institute site specific outcomes before and after initiation of the Cardiogenic Shock team on January 1, 2017; (3) to compare outcomes related to early implementation of mechanical circulatory support and hemodynamic-guided management versus historical controls; (4) to assess survival to discharge rate in patients receiving intervention from the designated shock team and (5) create a clinical archive of Cardiogenic Shock patient characteristics for future analysis and the support of translational research studies. This is an observational, retrospective, single center study. Retrospective and prospective data will be collected in patients treated at the Inova Heart and Vascular Institute with documented cardiogenic shock as a result of acute decompensated heart failure or acute myocardial infarction. This registry will include data from patients prior to and after the initiation of the multidisciplinary Cardiogenic Shock team on January 1, 2017. Clinical outcomes associated with early multidisciplinary team intervention will be analyzed. In the study group, all patients evaluated for documented cardiogenic shock (acute decompensated heart failure cardiogenic shock, acute myocardial infarction cardiogenic shock) treated at the Inova Heart and Vascular Institute by the Cardiogenic Shock team will be included. An additional historical Inova Heart and Vascular Institute control group will be analyzed as a comparator. Means with standard deviations will be reported for outcomes. For categorical variables, frequencies and percentages will be presented. For continuous variables, the number of subjects, mean, standard deviation, minimum, 25th percentile, median, 75th percentile and maximum will be reported. Reported differences will include standard errors and 95% CI. Preliminary data analysis for the year 2017 has been completed. Compared to a baseline 2016 survival rate of 47.0%, from 2017 to 2018, CS survival rates were increased to 57.9% (58/110) and 81.3% (81/140), respectively (P=.01 for both). Study data will continue to be collected until December 31, 2018. The preliminary results of this study demonstrate that the INOVA SHOCK team approach to the treatment of Cardiogenic Shock with early team activation, rapid initiation of mechanical circulatory support, hemodynamic-guided management, and strict protocol adherence is associated with superior clinical outcomes: survival to discharge and overall survival when compared to 2015 and 2016 outcomes prior to Shock team initiation. What may limit the generalization of these results of this study to other populations are site specific; expertise of the team, strict algorithm adherence based on the INOVA SHOCK protocol, and staff commitment to timely team activation. Retrospective clinical outcomes (acute decompensated heart failure cardiogenic shock, acute myocardial infarction cardiogenic shock) demonstrated an increase in current survival rates when compared to pre-Cardiogenic Shock team initiation, rapid team activation and diagnosis and timely utilization of mechanical circulatory support. ClinicalTrials.gov NCT03378739; https://clinicaltrials.gov/ct2/show/NCT03378739 (Archived by WebCite at http://www.webcitation.org/701vstDGd). ©Behnam Tehrani, Alexander Truesdell, Ramesh Singh, Charles Murphy, Patricia Saulino. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 28.06.2018.

A randomized controlled trial of post-extubation bubble continuous positive airway pressure versus Infant Flow Driver continuous positive airway pressure in preterm infants with respiratory distress syndrome.

PubMed

Gupta, Samir; Sinha, Sunil K; Tin, Win; Donn, Steven M

2009-05-01

To compare the efficacy and safety of bubble continuous positive airway pressure (CPAP) and Infant Flow Driver (IFD) CPAP for the post-extubation management of preterm infants with respiratory distress syndrome (RDS). A total of 140 preterm infants at 24 to 29 weeks' gestation or with a birth weight of 600 to 1500 g who were ventilated at birth for RDS were randomized to receive either IFD CPAP (a variable-flow device) or bubble CPAP (a continuous-flow device). A standardized protocol was used for extubation and CPAP. No crossover was allowed. The primary outcome was successful extubation maintained for at least 72 hours. Secondary outcomes included successful extubation maintained for 7 days, total duration of CPAP support, chronic lung disease, and complications of prematurity. Seventy-one infants were randomized to bubble CPAP, and 69 were randomized to IFD CPAP. Mean gestational age and birth weight were similar in the 2 groups, as were the proportions of infants who achieved successful extubation for 72 hours and for 7 days. However, the median duration of CPAP support was 50% shorter in the infants on bubble CPAP. Moreover, in the subset of infants who were ventilated for less than 14 days, the infants on bubble CPAP had a significantly lower extubation failure rate. There was no difference in the incidence of chronic lung disease or other complications between the 2 study groups. Bubble CPAP is as effective as IFD CPAP in the post-extubation management of infants with RDS; however, in infants ventilated for < or = 14 days, bubble CPAP is associated with a significantly higher rate of successful extubation. Bubble CPAP also is associated with a significantly reduced duration of CPAP support.

Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement.

PubMed

Dupont, Corinne; Occelli, Pauline; Deneux-Tharaux, Catherine; Touzet, Sandrine; Duclos, Antoine; Bouvier-Colle, Marie-Hélène; Rudigoz, René-Charles; Huissoud, Cyril

2014-07-01

Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement To use statistical process control charts to describe trends in the prevalence of severe postpartum haemorrhage after vaginal delivery. This assessment was performed 7 years after we initiated a continuous quality improvement programme that began with regular criteria-based audits Observational descriptive study, in a French maternity unit in the Rhône-Alpes region. Quarterly clinical audit meetings to analyse all cases of severe postpartum haemorrhage after vaginal delivery and provide feedback on quality of care with statistical process control tools. The primary outcomes were the prevalence of severe PPH after vaginal delivery and its quarterly monitoring with a control chart. The secondary outcomes included the global quality of care for women with severe postpartum haemorrhage, including the performance rate of each recommended procedure. Differences in these variables between 2005 and 2012 were tested. From 2005 to 2012, the prevalence of severe postpartum haemorrhage declined significantly, from 1.2% to 0.6% of vaginal deliveries (p<0.001). Since 2010, the quarterly rate of severe PPH has not exceeded the upper control limits, that is, been out of statistical control. The proportion of cases that were managed consistently with the guidelines increased for all of their main components. Implementation of continuous quality improvement efforts began seven years ago and used, among other tools, statistical process control charts. During this period, the prevalence of severe postpartum haemorrhage after vaginal delivery has been reduced by 50%. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Maximum-entropy probability distributions under Lp-norm constraints

NASA Technical Reports Server (NTRS)

Dolinar, S.

1991-01-01

Continuous probability density functions and discrete probability mass functions are tabulated which maximize the differential entropy or absolute entropy, respectively, among all probability distributions with a given L sub p norm (i.e., a given pth absolute moment when p is a finite integer) and unconstrained or constrained value set. Expressions for the maximum entropy are evaluated as functions of the L sub p norm. The most interesting results are obtained and plotted for unconstrained (real valued) continuous random variables and for integer valued discrete random variables. The maximum entropy expressions are obtained in closed form for unconstrained continuous random variables, and in this case there is a simple straight line relationship between the maximum differential entropy and the logarithm of the L sub p norm. Corresponding expressions for arbitrary discrete and constrained continuous random variables are given parametrically; closed form expressions are available only for special cases. However, simpler alternative bounds on the maximum entropy of integer valued discrete random variables are obtained by applying the differential entropy results to continuous random variables which approximate the integer valued random variables in a natural manner. All the results are presented in an integrated framework that includes continuous and discrete random variables, constraints on the permissible value set, and all possible values of p. Understanding such as this is useful in evaluating the performance of data compression schemes.

Continuous Positive Airway Pressure versus Mechanical Ventilation on the Fist Day of Life in Very Low-Birth-Weight Infants

PubMed Central

Flannery, Dustin D.; O’Donnell, Elizabeth; Kornhauser, Mike; Dysart, Kevin; Greenspan, Jay; Aghai, Zubair H.

2017-01-01

Objective The objective of this study was to determine differences in the incidence of bronchopulmonary dysplasia (BPD) or death in very low-birth-weight (VLBW) infants managed successfully on continuous positive airway pressure (CPAP) versus mechanical ventilation on the first day of life (DOL). Study Design This is a retrospective analysis of the Alere neonatal database for infants born between January 2009 and December 2014, weighing ≤ 1,500 g. Baseline demographics, clinical characteristics, and outcomes were compared between the two groups. Multivariate regression analysis was performed to control the variables that differ in bivariate analysis. Results In this study, 4,629 infants (birth weight 1,034 ± 290 g, gestational age 28.1 ± 2.5 weeks) met the inclusion criteria. The successful use of early CPAP was associated with a significant reduction in BPD or death (p < 0.001), as well as days to room air, decreased oxygen use at discharge, lower risk for severe intraventricular hemorrhage, and patent ductus arteriosus requiring surgical ligation (p < 0.001 for all outcomes). Conclusion Successful use of early CPAP on the first DOL in VLBW infants is associated with a reduced risk of BPD or death. PMID:27057767

Prospective monitoring improves outcomes of primary total hip replacement: a cohort study

PubMed Central

Streubel, Philipp N; Pachón, Marcela; Kerguelén, Carlos A; Navas, José; Portocarrero, Julio; Pesantez, Rodrigo F; Zayed, Gamal; Carrillo, Germán; Llinás, Adolfo M

2009-01-01

Background Over the past decade several studies have questioned current standards of patient safety in health care delivery. In response, our institution started a clinical pathway for total hip replacement in 1996. Prospective monitoring with regular feedback sessions to the individuals involved in patient care did however not start until 2003. The present study evaluates the effect of prospective monitoring on outcomes of total hip replacement. Methods Clinical records of patients undergoing primary elective total hip replacement between 1997 and 2004 were reviewed. Data on adverse events as well as adherence to protocols for venous thromboembolism prophylaxis were extracted retrospectively for the period 1997 to 2001 and prospectively from 2003 to 2004. Results were compared and analyzed in order to establish possible improvement in outcomes. Data was analyzed with Chi-square or Fisher's Exact test for categorical variables and Student's t-test for continuous variables. Alpha was set as less than 5% and analysis was performed with Stata 9.0 for Macintosh. Results Two-hundred and eighty-three patients were included from 1997 to 2001, and 62 from 2003 to 2004. Mean age, male to female ratio and initial diagnosis were similar in both groups. At least one adverse event occurred in 45% of patients in 1997–2001 and in 21% in 2003–2004 (p < 0.001). In-hospital hip dislocations occurred in 6% and 0% (p = 0.05), oliguria in 19% and 5% (p = 0.007), SSI and VTE in 3% and 0% (p = 0.37), adverse drug reactions in 11% and 13% (p = 0.66) and non-adherence to VTE prophylaxis protocols in 15% and 2% of cases respectively (p = 0.002). Conclusion Overall rate of adverse events as well as in-hospital hip dislocations, oliguria and non-adherence to VTE prophylaxis protocols were significantly reduced during the second period. We conclude that clinical pathways alone are insufficient to improve patient safety and require prospective monitoring and continuous feedback to health care providers in order to achieve the desired effect. PMID:19366438

Multivariable fractional polynomial interaction to investigate continuous effect modifiers in a meta-analysis on higher versus lower PEEP for patients with ARDS.

PubMed

Kasenda, Benjamin; Sauerbrei, Willi; Royston, Patrick; Mercat, Alain; Slutsky, Arthur S; Cook, Deborah; Guyatt, Gordon H; Brochard, Laurent; Richard, Jean-Christophe M; Stewart, Thomas E; Meade, Maureen; Briel, Matthias

2016-09-08

A recent individual patient data (IPD) meta-analysis suggested that patients with moderate or severe acute respiratory distress syndrome (ARDS) benefit from higher positive end-expiratory pressure (PEEP) ventilation strategies. However, thresholds for continuous variables (eg, hypoxaemia) are often arbitrary and linearity assumptions in regression approaches may not hold; the multivariable fractional polynomial interaction (MFPI) approach can address both problems. The objective of this study was to apply the MFPI approach to investigate interactions between four continuous patient baseline variables and higher versus lower PEEP on clinical outcomes. Pooled data from three randomised trials in intensive care identified by a systematic review. 2299 patients with acute lung injury requiring mechanical ventilation. Higher (N=1136) versus lower PEEP (N=1163) ventilation strategy. Prespecified outcomes included mortality, time to death and time-to-unassisted breathing. We examined the following continuous baseline characteristics as potential effect modifiers using MFPI: PaO2/FiO2 (arterial partial oxygen pressure/ fraction of inspired oxygen), oxygenation index, respiratory system compliance (tidal volume/(inspiratory plateau pressure-PEEP)) and body mass index (BMI). We found that for patients with PaO2/FiO2 below 150 mm Hg, but above 100 mm Hg or an oxygenation index above 12 (moderate ARDS), higher PEEP reduces hospital mortality, but the beneficial effect appears to level off for patients with very severe ARDS. Patients with mild ARDS (PaO2/FiO2 above 200 mm Hg or an oxygenation index below 10) do not seem to benefit from higher PEEP and might even be harmed. For patients with a respiratory system compliance above 40 mL/cm H2O or patients with a BMI above 35 kg/m(2), we found a trend towards reduced mortality with higher PEEP, but there is very weak statistical confidence in these findings. MFPI analyses suggest a nonlinear effect modification of higher PEEP ventilation by PaO2/FiO2 and oxygenation index with reduced mortality for some patients suffering from moderate ARDS. CRD42012003129. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Scaling Factor Variability and Toxicokinetic Outcomes in Children

EPA Science Inventory

Abstract title: Scaling Factor Variability and Toxicokinetic Outcomes in ChildrenBackgroundBiotransformation rates (Vmax) extrapolated from in vitro data are used increasingly in human physiologically based pharmacokinetic (PBPK) models. PBPK models are widely used in human hea...

The role of message framing in promoting MMR vaccination: evidence of a loss-frame advantage.

PubMed

Abhyankar, Purva; O'Connor, Daryl B; Lawton, Rebecca

2008-01-01

This study examined the effects of message framing on intentions to obtain the measles, mumps and rubella (MMR) vaccine for one's child and investigated whether Theory of Planned Behaviour (TPB) and perceived outcome efficacy variables mediate and/or moderate message framing effects. One hundred and forty women read either a loss-framed or gain-framed message and then completed measures assessing their intentions to obtain the MMR vaccine for their child, and TPB and outcome efficacy variables. Exposure to the loss frame increased intentions to obtain the MMR vaccine and influenced perceptions of outcome efficacy. This suggests that outcome efficacy, but not other TPB variables may mediate framing effects within the context of MMR vaccination. Message frame, in addition to TPB variables, significantly predicted unique variance in behavioural intentions. These findings are discussed within the context of Prospect Theory, perceived risk and prevention/detection behaviours.

Variables affecting learning in a simulation experience: a mixed methods study.

PubMed

Beischel, Kelly P

2013-02-01

The primary purpose of this study was to test a hypothesized model describing the direct effects of learning variables on anxiety and cognitive learning outcomes in a high-fidelity simulation (HFS) experience. The secondary purpose was to explain and explore student perceptions concerning the qualities and context of HFS affecting anxiety and learning. This study used a mixed methods quantitative-dominant explanatory design with concurrent qualitative data collection to examine variables affecting learning in undergraduate, beginning nursing students (N = 124). Being ready to learn, having a strong auditory-verbal learning style, and being prepared for simulation directly affected anxiety, whereas learning outcomes were directly affected by having strong auditory-verbal and hands-on learning styles. Anxiety did not quantitatively mediate cognitive learning outcomes as theorized, although students qualitatively reported debilitating levels of anxiety. This study advances nursing education science by providing evidence concerning variables affecting learning outcomes in HFS.

Patient or treatment centre? Where are efforts invested to improve cancer patients' psychosocial outcomes?

PubMed Central

Carey, ML; Clinton-McHarg, T; Sanson-Fisher, RW; Campbell, S; Douglas, HE

2011-01-01

The psychosocial outcomes of cancer patients may be influenced by individual-level, social and treatment centre predictors. This paper aimed to examine the extent to which individual, social and treatment centre variables have been examined as predictors or targets of intervention for psychosocial outcomes of cancer patients. Medline was searched to find studies in which the psychological outcomes of cancer patient were primary variables. Papers published in English between 1999 and 2009 that reported primary data relevant to psychosocial outcomes for cancer patients were included, with 20% randomly selected for further coding. Descriptive studies were coded for inclusion of individual, social or treatment centre variables. Intervention studies were coded to determine if the unit of intervention was the individual patient, social unit or treatment centre. After random sampling, 412 publications meeting the inclusion criteria were identified, 169 were descriptive and 243 interventions. Of the descriptive papers 95.0% included individual predictors, and 5.0% social predictors. None of the descriptive papers examined treatment centre variables as predictors of psychosocial outcomes. Similarly, none of the interventions evaluated the effectiveness of treatment centre interventions for improving psychosocial outcomes. Potential reasons for the overwhelming dominance of individual predictors and individual-focused interventions in psychosocial literature are discussed. PMID:20646035

National Databases for Neurosurgical Outcomes Research: Options, Strengths, and Limitations.

PubMed

Karhade, Aditya V; Larsen, Alexandra M G; Cote, David J; Dubois, Heloise M; Smith, Timothy R

2017-08-05

Quality improvement, value-based care delivery, and personalized patient care depend on robust clinical, financial, and demographic data streams of neurosurgical outcomes. The neurosurgical literature lacks a comprehensive review of large national databases. To assess the strengths and limitations of various resources for outcomes research in neurosurgery. A review of the literature was conducted to identify surgical outcomes studies using national data sets. The databases were assessed for the availability of patient demographics and clinical variables, longitudinal follow-up of patients, strengths, and limitations. The number of unique patients contained within each data set ranged from thousands (Quality Outcomes Database [QOD]) to hundreds of millions (MarketScan). Databases with both clinical and financial data included PearlDiver, Premier Healthcare Database, Vizient Clinical Data Base and Resource Manager, and the National Inpatient Sample. Outcomes collected by databases included patient-reported outcomes (QOD); 30-day morbidity, readmissions, and reoperations (National Surgical Quality Improvement Program); and disease incidence and disease-specific survival (Surveillance, Epidemiology, and End Results-Medicare). The strengths of large databases included large numbers of rare pathologies and multi-institutional nationally representative sampling; the limitations of these databases included variable data veracity, variable data completeness, and missing disease-specific variables. The improvement of existing large national databases and the establishment of new registries will be crucial to the future of neurosurgical outcomes research. Copyright © 2017 by the Congress of Neurological Surgeons

Multivariate outcome prediction in traumatic brain injury with focus on laboratory values.

PubMed

Nelson, David W; Rudehill, Anders; MacCallum, Robert M; Holst, Anders; Wanecek, Michael; Weitzberg, Eddie; Bellander, Bo-Michael

2012-11-20

Traumatic brain injury (TBI) is a major cause of morbidity and mortality. Identifying factors relevant to outcome can provide a better understanding of TBI pathophysiology, in addition to aiding prognostication. Many common laboratory variables have been related to outcome but may not be independent predictors in a multivariate setting. In this study, 757 patients were identified in the Karolinska TBI database who had retrievable early laboratory variables. These were analyzed towards a dichotomized Glasgow Outcome Scale (GOS) with logistic regression and relevance vector machines, a non-linear machine learning method, univariately and controlled for the known important predictors in TBI outcome: age, Glasgow Coma Score (GCS), pupil response, and computed tomography (CT) score. Accuracy was assessed with Nagelkerke's pseudo R². Of the 18 investigated laboratory variables, 15 were found significant (p<0.05) towards outcome in univariate analyses. In contrast, when adjusting for other predictors, few remained significant. Creatinine was found an independent predictor of TBI outcome. Glucose, albumin, and osmolarity levels were also identified as predictors, depending on analysis method. A worse outcome related to increasing osmolarity may warrant further study. Importantly, hemoglobin was not found significant when adjusted for post-resuscitation GCS as opposed to an admission GCS, and timing of GCS can thus have a major impact on conclusions. In total, laboratory variables added an additional 1.3-4.4% to pseudo R².

An exploration of predictors of children's nurses' attitudes, knowledge, confidence and clinical behavioural intentions towards children and young people who self-harm.

PubMed

Carter, Tim; Latif, Asam; Callaghan, Patrick; Manning, Joseph C

2018-03-22

To explore the potential predictors of children's nurses' attitudes, knowledge and confidence towards caring for children and young people admitted to hospital with self-harm. Admissions to paediatric inpatient settings for individuals who have self-harmed are growing. Limited previous research suggests that nurses have mixed attitudes towards people who have self-harmed and potentially lack the confidence to provide effective care. There is a specific paucity of research in this area for children's nurses. A cross-sectional descriptive survey was used to gather data for exploration of variables associated with attitudes, confidence, knowledge and clinical behavioural intentions of 98 registered children's nurses in a single tertiary children's hospital, colocated in a large acute NHS Trust in the UK. Data were collected over a 4 weeks in 2015, using an online survey tool. The predictive effect of several demographic variables was tested on the outcomes of attitudes, knowledge, confidence and behavioural intentions, which were collected using relevant, previously used outcome measures. Increased experience was found to be associated with improved attitudes relating to negativity. Previous training in caring for children who had self-harmed was found to be associated with improved attitudes around perceived effectiveness of their care. Higher academic qualifications and having undertaken previous training on self-harm were each found to be associated with increased knowledge of self-harm, and increased age was associated with reduced knowledge of self-harm. This study provides an initial exploration of variables associated with attitudes, knowledge, confidence and behaviour intentions of registered children's nurses in relation to caring for CYP who have self-harmed. Targeted training on caring for CYP who have self-harmed should be considered as a component of continuing education for registered children's nurses in the UK to improve the experience and outcomes for this patient group. ©2018 The Authors Journal of Clinical Nursing Published by John Wiley & Sons Ltd.

Robotic laparoscopic radical prostatectomy for biopsy Gleason 8 to 10: prediction of favorable pathologic outcome with preoperative parameters.

PubMed

Shikanov, Sergey A; Thong, Alan; Gofrit, Ofer N; Zagaja, Gregory P; Steinberg, Gary D; Shalhav, Arieh L; Zorn, Kevin C

2008-07-01

We sought to evaluate the pathologic results and postoperative outcomes for men undergoing robot-assisted laparoscopic radical prostatectomy (RLRP) for biopsy Gleason score (GS) 8 to 10 disease. Stratification of these patients according to preoperative variables was also performed in an attempt to predict organ-confined cancer. A prospective RLRP database identified all patients with preoperative biopsy GS 8 to 10. Variables, including prostate-specific antigen (PSA), percent positive biopsy cores (%PBC), maximal percentage of cancer in biopsy core (%MCB), clinical stage, pathologic stage, pathologic GS, surgical margins status, lymph node status, time to biochemical recurrence, and recurrence rate, were evaluated. Preoperative variables were treated as continuous and categorical using PSA, %PBC and %MCB cutoffs of 10 ng/mL, 50%, and 30%, respectively. Between February 2003 and September 2007, a total of 1225 RLRPs were performed at the University of Chicago Medical Center. Seventy-two (5.9%) patients had preoperative biopsy GS 8 to 10. Two patients received neoadjuvant hormonal therapy and were excluded. Among 70 patients evaluated, 33 (47%) had organconfined (pT(2)N0) disease. Forty (60.6%) patients had pathologic downgrading to GS

Systematic review of statistically-derived models of immunological response in HIV-infected adults on antiretroviral therapy in Sub-Saharan Africa.

PubMed

Sempa, Joseph B; Ujeneza, Eva L; Nieuwoudt, Martin

2017-01-01

In Sub-Saharan African (SSA) resource limited settings, Cluster of Differentiation 4 (CD4) counts continue to be used for clinical decision making in antiretroviral therapy (ART). Here, HIV-infected people often remain with CD4 counts <350 cells/μL even after 5 years of viral load suppression. Ongoing immunological monitoring is necessary. Due to varying statistical modeling methods comparing immune response to ART across different cohorts is difficult. We systematically review such models and detail the similarities, differences and problems. 'Preferred Reporting Items for Systematic Review and Meta-Analyses' guidelines were used. Only studies of immune-response after ART initiation from SSA in adults were included. Data was extracted from each study and tabulated. Outcomes were categorized into 3 groups: 'slope', 'survival', and 'asymptote' models. Wordclouds were drawn wherein the frequency of variables occurring in the reviewed models is indicated by their size and color. 69 covariates were identified in the final models of 35 studies. Effect sizes of covariates were not directly quantitatively comparable in view of the combination of differing variables and scale transformation methods across models. Wordclouds enabled the identification of qualitative and semi-quantitative covariate sets for each outcome category. Comparison across categories identified sex, baseline age, baseline log viral load, baseline CD4, ART initiation regimen and ART duration as a minimal consensus set. Most models were different with respect to covariates included, variable transformations and scales, model assumptions, modelling strategies and reporting methods, even for the same outcomes. To enable comparison across cohorts, statistical models would benefit from the application of more uniform modelling techniques. Historic efforts have produced results that are anecdotal to individual cohorts only. This study was able to define 'prior' knowledge in the Bayesian sense. Such information has value for prospective modelling efforts.

A score model for the continuous grading of early allograft dysfunction severity.

PubMed

Pareja, Eugenia; Cortes, Miriam; Hervás, David; Mir, José; Valdivieso, Andrés; Castell, José V; Lahoz, Agustín

2015-01-01

Early allograft dysfunction (EAD) dramatically influences graft and patient outcomes. A lack of consensus on an EAD definition hinders comparisons of liver transplant outcomes and management of recipients among and within centers. We sought to develop a model for the quantitative assessment of early allograft function [Model for Early Allograft Function Scoring (MEAF)] after transplantation. A retrospective study including 1026 consecutive liver transplants was performed for MEAF score development. Multivariate data analysis was used to select a small number of postoperative variables that adequately describe EAD. Then, the distribution of these variables was mathematically modeled to assign a score for each actual variable value. A model, based on easily obtainable clinical parameters (ie, alanine aminotransferase, international normalized ratio, and bilirubin) and scoring liver function from 0 to 10, was built. The MEAF score showed a significant association with patient and graft survival at 3-, 6- and 12-month follow-ups. Hepatic steatosis and age for donors; cold/warm ischemia times and postreperfusion syndrome for surgery; and intensive care unit and hospital stays, Model for End-Stage Liver Disease and Child-Pugh scores, body mass index, and fresh frozen plasma transfusions for recipients were factors associated significantly with EAD. The model was satisfactorily validated by its application to an independent set of 200 patients who underwent liver transplantation at a different center. In conclusion, a model for the quantitative assessment of EAD severity has been developed and validated for the first time. The MEAF provides a more accurate graft function assessment than current categorical classifications and may help clinicians to make early enough decisions on retransplantation benefits. Furthermore, the MEAF score is a predictor of recipient and graft survival. The standardization of the criteria used to define EAD may allow reliable comparisons of recipients' treatments and transplant outcomes among and within centers. © 2014 American Association for the Study of Liver Diseases.

The impact of a disease management programme for type 2 diabetes on health-related quality of life: multilevel analysis of a cluster-randomised controlled trial.

PubMed

Panisch, Sigrid; Johansson, Tim; Flamm, Maria; Winkler, Henrike; Weitgasser, Raimund; Sönnichsen, Andreas C

2018-01-01

Type 2 diabetes is a chronic disease associated with poorer health outcomes and decreased health related quality of life (HRQoL). The aim of this analysis was to explore the impact of a disease management programme (DMP) in type 2 diabetes on HRQoL. A multilevel model was used to explain the variation in EQ-VAS. A cluster-randomized controlled trial-analysis of the secondary endpoint HRQoL. Our study population were general practitioners and patients in the province of Salzburg. The DMP "Therapie-Aktiv" was implemented in the intervention group, and controls received usual care. Outcome measure was a change in EQ-VAS after 12 months. For comparison of rates, we used Fisher's Exact test; for continuous variables the independent T test or Welch test were used. In the multilevel modeling, we examined various models, continuously adding variables to explain the variation in the dependent variable, starting with an empty model, including only the random intercept. We analysed random effects parameters in order to disentangle variation of the final EQ-VAS. The EQ-VAS significantly increased within the intervention group (mean difference 2.19, p = 0.005). There was no significant difference in EQ-VAS between groups (mean difference 1.00, p = 0.339). In the intervention group the improvement was more distinct in women (2.46, p = 0.036) compared to men (1.92, p = 0.063). In multilevel modeling, sex, age, family and work circumstances, any macrovascular diabetic complication, duration of diabetes, baseline body mass index and baseline EQ-VAS significantly influence final EQ-VAS, while DMP does not. The final model explains 28.9% (EQ-VAS) of the total variance. Most of the unexplained variance was found on patient-level (95%) and less on GP-level (5%). DMP "Therapie-Aktiv" has no significant impact on final EQ-VAS. The impact of DMPs in type 2 diabetes on HRQoL is still unclear and future programmes should focus on patient specific needs and predictors in order to improve HRQoL. Trial registration Current Controlled trials Ltd., ISRCTN27414162.

Robust discovery of genetic associations incorporating gene-environment interaction and independence.

PubMed

Tchetgen Tchetgen, Eric

2011-03-01

This article considers the detection and evaluation of genetic effects incorporating gene-environment interaction and independence. Whereas ordinary logistic regression cannot exploit the assumption of gene-environment independence, the proposed approach makes explicit use of the independence assumption to improve estimation efficiency. This method, which uses both cases and controls, fits a constrained retrospective regression in which the genetic variant plays the role of the response variable, and the disease indicator and the environmental exposure are the independent variables. The regression model constrains the association of the environmental exposure with the genetic variant among the controls to be null, thus explicitly encoding the gene-environment independence assumption, which yields substantial gain in accuracy in the evaluation of genetic effects. The proposed retrospective regression approach has several advantages. It is easy to implement with standard software, and it readily accounts for multiple environmental exposures of a polytomous or of a continuous nature, while easily incorporating extraneous covariates. Unlike the profile likelihood approach of Chatterjee and Carroll (Biometrika. 2005;92:399-418), the proposed method does not require a model for the association of a polytomous or continuous exposure with the disease outcome, and, therefore, it is agnostic to the functional form of such a model and completely robust to its possible misspecification.

Pediatric anesthesia after APRICOT (Anaesthesia PRactice In Children Observational Trial): who should do it?

PubMed

Habre, Walid

2018-06-01

This review highlights the requirements for harmonization of training, certification and continuous professional development and discusses the implications for anesthesia management of children in Europe. A large prospective cohort study, Anaesthesia PRactice In Children Observational Trial (APRICOT), revealed a high incidence of perioperative severe critical events and a large variability of anesthesia practice across 33 European countries. Relevantly, quality improvement programs have been implemented in North America, which precisely define the requirements to manage anesthesia care for children. These programs, with the introduction of an incident-reporting system at local and national levels, could contribute to the improvement of anesthesia care for children in Europe. The main factors that likely contributed to the APRICOT study results are discussed with the goal of defining clear requirement guidelines for anesthetizing children. Emphasis is placed on the importance of an incident-reporting system that can be used for both competency-based curriculum for postgraduate training as well as for continuous professional development. Variability in training as well as in available resources, equipment and facilities limit the generalization of some of the APRICOT results. Finally, the impact on case outcome of the total number of pediatric cases attended by the anesthesiologist should be taken into consideration along with the level of expertise of the anesthesiologist for complex pediatric anesthesia cases.

A Geometrical Framework for Covariance Matrices of Continuous and Categorical Variables

ERIC Educational Resources Information Center

Vernizzi, Graziano; Nakai, Miki

2015-01-01

It is well known that a categorical random variable can be represented geometrically by a simplex. Accordingly, several measures of association between categorical variables have been proposed and discussed in the literature. Moreover, the standard definitions of covariance and correlation coefficient for continuous random variables have been…

Neutrophil-to-lymphocyte ratio as a predictor of worsening renal function in diabetic patients (3-year follow-up study).

PubMed

Azab, Basem; Daoud, Jacques; Naeem, Fahad Ben; Nasr, Rabih; Ross, Jennifer; Ghimire, Pratima; Siddiqui, Ayesha; Azzi, Nadine; Rihana, Nancy; Abdallah, Marie; Azzi, Nassif; Patel, Parishram; Kleiner, Morton; El-Sayegh, Suzanne

2012-01-01

Previous studies have demonstrated the role of inflammation in diabetic nephropathy (DN). Neutrophil to lymphocyte ratio (NLR) rather than other white cell parameters was found to be a useful inflammatory marker to predict adverse outcomes in medical and surgical conditions. Nevertheless, the value of NLR in predicting DN has not been elucidated. An observational study included 338 diabetic patients, who were followed at our clinic between 2007 and 2009. We arranged our patients into tertiles according to their 2007 NLR. The primary outcome was continuous decrease of GFR >12 mL/min between 2007 and 2009 with the last GFR <60 mL/min. The lowest NLR tertile had fewer patients (2.7%) with primary outcome (i.e., worsening renal function) compared with middle and highest NLR tertiles, which had more patients with primary outcomes (8.7% and 11.5%, respectively) with a significant p-value 0.0164. When other potential confounders were individually analyzed with NLR tertile, the NLR tertiles remained a significant predictor of poor GFR outcome in the presence of other variables (hemoglobin A1C, systolic blood pressure, diastolic blood pressure, age, and congestive heart failure with p-values 0.018, 0.019, 0.017, 0.033, and 0.022, respectively). NLR predicted the worsening of the renal function in diabetic patients. Further studies are needed to confirm this result.

Tutorial in Biostatistics: Instrumental Variable Methods for Causal Inference*

PubMed Central

Baiocchi, Michael; Cheng, Jing; Small, Dylan S.

2014-01-01

A goal of many health studies is to determine the causal effect of a treatment or intervention on health outcomes. Often, it is not ethically or practically possible to conduct a perfectly randomized experiment and instead an observational study must be used. A major challenge to the validity of observational studies is the possibility of unmeasured confounding (i.e., unmeasured ways in which the treatment and control groups differ before treatment administration which also affect the outcome). Instrumental variables analysis is a method for controlling for unmeasured confounding. This type of analysis requires the measurement of a valid instrumental variable, which is a variable that (i) is independent of the unmeasured confounding; (ii) affects the treatment; and (iii) affects the outcome only indirectly through its effect on the treatment. This tutorial discusses the types of causal effects that can be estimated by instrumental variables analysis; the assumptions needed for instrumental variables analysis to provide valid estimates of causal effects and sensitivity analysis for those assumptions; methods of estimation of causal effects using instrumental variables; and sources of instrumental variables in health studies. PMID:24599889

Balance and ambulation improvements in individuals with chronic incomplete spinal cord injury using locomotor training-based rehabilitation.

PubMed

Harkema, Susan J; Schmidt-Read, Mary; Lorenz, Douglas J; Edgerton, V Reggie; Behrman, Andrea L

2012-09-01

To evaluate the effects of intensive locomotor training on balance and ambulatory function at enrollment and discharge during outpatient rehabilitation after incomplete SCI. Prospective observational cohort. Seven outpatient rehabilitation centers from the Christopher and Dana Reeve Foundation NeuroRecovery Network (NRN). Patients (N=196) with American Spinal Injury Association Impairment Scale (AIS) grade C or D SCI who received at least 20 locomotor training treatment sessions in the NRN. Intensive locomotor training, including step training using body-weight support and manual facilitation on a treadmill followed by overground assessment and community integration. Berg Balance Scale; Six-Minute Walk Test; 10-Meter Walk Test. Outcome measures at enrollment showed high variability between patients with AIS grades C and D. Significant improvement from enrollment to final evaluation was observed in balance and walking measures for patients with AIS grades C and D. The magnitude of improvement significantly differed between AIS groups for all measures. Time since SCI was not associated significantly with outcome measures at enrollment, but was related inversely to levels of improvement. Significant variability in baseline values of functional outcome measures is evident after SCI in individuals with AIS grades C and D and significant functional recovery can continue to occur even years after injury when provided with locomotor training. These results indicate that rehabilitation, which provides intensive activity-based therapy, can result in functional improvements in individuals with chronic incomplete SCI. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

National Trends in Demographics and Outcomes Following Cervical Fusion for Cervical Spondylotic Myelopathy

PubMed Central

Vonck, Caroline E.; Tanenbaum, Joseph E.; Smith, Gabriel A.; Benzel, Edward C.; Mroz, Thomas E.; Steinmetz, Michael P.

2017-01-01

Study Design: Retrospective trends analysis. Objectives: Cervical fusion is a common adjunctive surgical modality used in the treatment of cervical spondylotic myelopathy (CSM). The purpose of this study was to quantify national trends in patient demographics, hospital characteristics, and outcomes in the surgical management of CSM. Methods: This was a retrospective study that used the National Inpatient Sample. The sample included all patients over 18 years of age with a diagnosis of CSM who underwent cervical fusion from 2003 to 2013. The outcome measures were in-hospital mortality, length of stay, and hospital charges. Chi-square tests were performed to compare categorical variables. Independent t tests were performed to compare continuous variables. Results: We identified 62 970 patients with CSM who underwent cervical fusion from 2003 to 2013. The number of fusions performed per year in the treatment of CSM increased from 3879 to 8181. The average age of all fusion patients increased from 58.2 to 60.6 years (P < .001). Length of stay did not change significantly from a mean of 3.7 days. In-hospital mortality decreased from 0.6% to 0.3% (P < .01). Hospital charges increased from $49 445 to $92 040 (P < .001). Conclusions: This study showed a dramatic increase in cervical fusions to treat CSM from 2003 to 2013 concomitant with increasing age of the patient population. Despite increases in average age and number of comorbidities, length of stay remained constant and a decrease in mortality was seen across the study period. However, hospital charges increased dramatically.

The Influence of Background Music on Learning in the Light of Different Theoretical Perspectives and the Role of Working Memory Capacity.

PubMed

Lehmann, Janina A M; Seufert, Tina

2017-01-01

This study investigates how background music influences learning with respect to three different theoretical approaches. Both the Mozart effect as well as the arousal-mood-hypothesis indicate that background music can potentially benefit learning outcomes. While the Mozart effect assumes a direct influence of background music on cognitive abilities, the arousal-mood-hypothesis assumes a mediation effect over arousal and mood. However, the seductive detail effect indicates that seductive details such as background music worsen learning. Moreover, as working memory capacity has a crucial influence on learning with seductive details, we also included the learner's working memory capacity as a factor in our study. We tested 81 college students using a between-subject design with half of the sample listening to two pop songs while learning a visual text and the other half learning in silence. We included working memory capacity in the design as a continuous organism variable. Arousal and mood scores before and after learning were collected as potential mediating variables. To measure learning outcomes we tested recall and comprehension. We did not find a mediation effect between background music and arousal or mood on learning outcomes. In addition, for recall performance there were no main effects of background music or working memory capacity, nor an interaction effect of these factors. However, when considering comprehension we did find an interaction between background music and working memory capacity: the higher the learners' working memory capacity, the better they learned with background music. This is in line with the seductive detail assumption.

The Influence of Background Music on Learning in the Light of Different Theoretical Perspectives and the Role of Working Memory Capacity

PubMed Central

Lehmann, Janina A. M.; Seufert, Tina

2017-01-01

This study investigates how background music influences learning with respect to three different theoretical approaches. Both the Mozart effect as well as the arousal-mood-hypothesis indicate that background music can potentially benefit learning outcomes. While the Mozart effect assumes a direct influence of background music on cognitive abilities, the arousal-mood-hypothesis assumes a mediation effect over arousal and mood. However, the seductive detail effect indicates that seductive details such as background music worsen learning. Moreover, as working memory capacity has a crucial influence on learning with seductive details, we also included the learner’s working memory capacity as a factor in our study. We tested 81 college students using a between-subject design with half of the sample listening to two pop songs while learning a visual text and the other half learning in silence. We included working memory capacity in the design as a continuous organism variable. Arousal and mood scores before and after learning were collected as potential mediating variables. To measure learning outcomes we tested recall and comprehension. We did not find a mediation effect between background music and arousal or mood on learning outcomes. In addition, for recall performance there were no main effects of background music or working memory capacity, nor an interaction effect of these factors. However, when considering comprehension we did find an interaction between background music and working memory capacity: the higher the learners’ working memory capacity, the better they learned with background music. This is in line with the seductive detail assumption. PMID:29163283

Isolating the Role of Psychological Dysfunction in Smoking Cessation Failure: Relations of Personality and Psychopathology to Attaining Smoking Cessation Milestones

PubMed Central

Leventhal, Adam M.; Japuntich, Sandra J.; Piper, Megan E.; Jorenby, Douglas E.; Schlam, Tanya R.; Baker, Timothy B.

2012-01-01

Research exploring psychological dysfunction as a predictor of smoking cessation success may be limited by nonoptimal predictor variables (i.e., categorical psychodiagnostic measures vs. continuous personality-based manifestations of dysfunction) and imprecise outcomes (i.e., summative point prevalence abstinence vs. constituent cessation milestone measures). Accordingly, this study evaluated the unique and overlapping relations of broad-spectrum personality traits (positive emotionality, negative emotionality, and constraint) and past-year psychopathology (anxiety, mood, and substance use disorder) to point prevalence abstinence and three smoking cessation milestones: (1) initiating abstinence; (2) first lapse; and (3) transition from lapse to relapse. Participants were daily smokers (N=1365) enrolled in a smoking cessation treatment study. In single predictor regression models, each manifestation of internalizing dysfunction (lower positive emotionality, higher negative emotionality, and anxiety and mood disorder) predicted failure at one or more cessation milestone. In simultaneous predictor models, lower positive and higher negative emotionality significantly predicted failure to achieve milestones after controlling for psychopathology. Psychopathology did not predict any outcome when controlling for personality. Negative emotionality showed the most robust and consistent effects, significantly predicting failure to initiate abstinence, earlier lapse, and lower point prevalence abstinence rates. Substance use disorder and constraint did not predict cessation outcomes, and no single variable predicted lapse-to-relapse transition. These findings suggest that personality-related manifestations of internalizing dysfunction are more accurate markers of affective sources of relapse risk than mood and anxiety disorders. Further, individuals with high trait negative emotionality may require intensive intervention to promote the initiation and early maintenance of abstinence. PMID:22642858

Pediatric Pulmonary Hemorrhage vs. Extrapulmonary Bleeding in the Differential Diagnosis of Hemoptysis.

PubMed

Vaiman, Michael; Klin, Baruch; Rosenfeld, Noa; Abu-Kishk, Ibrahim

2017-01-01

Hemoptysis is an important symptom which causes a major concern, and warrants immediate diagnostic attention. The authors compared a group of patients with pediatric pulmonary hemorrhage with pediatric patients diagnosed with extrapulmonary bleeding focusing on differences in etiology, outcome and differential diagnosis of hemoptysis. We performed the retrospective analysis of medical charts of 134 pediatric patients admitted to the Emergency Department because of pulmonary and extrapulmonary hemorrhage and were diagnosed with suspected hemoptysis or developed hemoptysis (ICD10-CM code R04.2). The cases with pulmonary hemorrhage (Group 1) were compared with cases of extrapulmonary bleeding (Group 2) using the Fisher Exact test or Pearson's χ 2 test for categorical variables. The t-test was used to assess differences between continuous variables of the patients in the two groups. Bloody cough was the presenting symptom in 73.9% of cases. 30 patients had pulmonary hemorrhage (Group 1), while 104 patients had extrapulmonary bleeding (Group 2). The underlying causes of bleeding in Group 2 included epistaxis, inflammatory diseases of nasopharynx and larynx, foreign bodies, gingivitis, and hypertrophy of adenoids. Mortality rate was 10% in Group 1, whereas Group 2 did not have any mortality outcomes during the observation period. Etiologycal factors were significantly different between hemoptysis and extrapulmonary bleeding in children. Our research suggested that pulmonary and extrapulmonary bleeding are two conditions that differ significantly and cannot be unified under one diagnostic code. It is important to differentiate between focal and diffuse cases, and between pulmonary and extrapulmonary hemorrhage due to the diversity of clinical courses and outcomes.

Bias and Bias Correction in Multisite Instrumental Variables Analysis of Heterogeneous Mediator Effects

ERIC Educational Resources Information Center

Reardon, Sean F.; Unlu, Fatih; Zhu, Pei; Bloom, Howard S.

2014-01-01

We explore the use of instrumental variables (IV) analysis with a multisite randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, an assumption known in the IV literature as the exclusion restriction.…

Mixture Factor Analysis for Approximating a Nonnormally Distributed Continuous Latent Factor with Continuous and Dichotomous Observed Variables

ERIC Educational Resources Information Center

Wall, Melanie M.; Guo, Jia; Amemiya, Yasuo

2012-01-01

Mixture factor analysis is examined as a means of flexibly estimating nonnormally distributed continuous latent factors in the presence of both continuous and dichotomous observed variables. A simulation study compares mixture factor analysis with normal maximum likelihood (ML) latent factor modeling. Different results emerge for continuous versus…

Fractal analysis for assessing tumour grade in microscopic images of breast tissue

NASA Astrophysics Data System (ADS)

Tambasco, Mauro; Costello, Meghan; Newcomb, Chris; Magliocco, Anthony M.

2007-03-01

In 2006, breast cancer is expected to continue as the leading form of cancer diagnosed in women, and the second leading cause of cancer mortality in this group. A method that has proven useful for guiding the choice of treatment strategy is the assessment of histological tumor grade. The grading is based upon the mitosis count, nuclear pleomorphism, and tubular formation, and is known to be subject to inter-observer variability. Since cancer grade is one of the most significant predictors of prognosis, errors in grading can affect patient management and outcome. Hence, there is a need to develop a breast cancer-grading tool that is minimally operator dependent to reduce variability associated with the current grading system, and thereby reduce uncertainty that may impact patient outcome. In this work, we explored the potential of a computer-based approach using fractal analysis as a quantitative measure of cancer grade for breast specimens. More specifically, we developed and optimized computational tools to compute the fractal dimension of low- versus high-grade breast sections and found them to be significantly different, 1.3+/-0.10 versus 1.49+/-0.10, respectively (Kolmogorov-Smirnov test, p<0.001). These results indicate that fractal dimension (a measure of morphologic complexity) may be a useful tool for demarcating low- versus high-grade cancer specimens, and has potential as an objective measure of breast cancer grade. Such prognostic value could provide more sensitive and specific information that would reduce inter-observer variability by aiding the pathologist in grading cancers.

Spanking, corporal punishment and negative long-term outcomes: a meta-analytic review of longitudinal studies.

PubMed

Ferguson, Christopher J

2013-02-01

Social scientists continue to debate the impact of spanking and corporal punishment (CP) on negative child outcomes including externalizing and internalizing behavior problems and cognitive performance. Previous meta-analytic reviews have mixed long- and short-term studies and relied on bivariate r, which may inflate effect sizes. The current meta-analysis focused on longitudinal studies, and compared effects using bivariate r and better controlled partial r coefficients controlling for time-1 outcome variables. Consistent with previous findings, results based on bivariate r found small but non-trivial long-term relationships between spanking/CP use and negative outcomes. Spanking and CP correlated .14 and .18 respectively with externalizing problems, .12 and .21 with internalizing problems and -.09 and -.18 with cognitive performance. However, when better controlled partial r coefficients (pr) were examined, results were statistically significant but trivial (at or below pr = .10) for externalizing (.07 for spanking, .08 for CP) and internalizing behaviors (.10 for spanking, insufficient studies for CP) and near the threshold of trivial for cognitive performance (-.11 for CP, insufficient studies for spanking). It is concluded that the impact of spanking and CP on the negative outcomes evaluated here (externalizing, internalizing behaviors and low cognitive performance) are minimal. It is advised that psychologists take a more nuanced approach in discussing the effects of spanking/CP with the general public, consistent with the size as well as the significance of their longitudinal associations with adverse outcomes.

Red cell distribution width does not predict stroke severity or functional outcome.

PubMed

Ntaios, George; Gurer, Ozgur; Faouzi, Mohamed; Aubert, Carole; Michel, Patrik

2012-01-01

Red cell distribution width was recently identified as a predictor of cardiovascular and all-cause mortality in patients with previous stroke. Red cell distribution width is also higher in patients with stroke compared with those without. However, there are no data on the association of red cell distribution width, assessed during the acute phase of ischemic stroke, with stroke severity and functional outcome. In the present study, we sought to investigate this relationship and ascertain the main determinants of red cell distribution width in this population. We used data from the Acute Stroke Registry and Analysis of Lausanne for patients between January 2003 and December 2008. Red cell distribution width was generated at admission by the Sysmex XE-2100 automated cell counter from ethylene diamine tetraacetic acid blood samples stored at room temperature until measurement. An χ(2) -test was performed to compare frequencies of categorical variables between different red cell distribution width quartiles, and one-way analysis of variance for continuous variables. The effect of red cell distribution width on severity and functional outcome was investigated in univariate and multivariate robust regression analysis. Level of significance was set at 95%. There were 1504 patients (72±15·76 years, 43·9% females) included in the analysis. Red cell distribution width was significantly associated to NIHSS (β-value=0·24, P=0·01) and functional outcome (odds ratio=10·73 for poor outcome, P<0·001) at univariate analysis but not multivariate. Prehospital Rankin score (β=0·19, P<0·001), serum creatinine (β=0·008, P<0·001), hemoglobin (β=-0·009, P<0·001), mean platelet volume (β=0·09, P<0·05), age (β=0·02, P<0·001), low ejection fraction (β=0·66, P<0·001) and antihypertensive treatment (β=0·32, P<0·001) were independent determinants of red cell distribution width. Red cell distribution width, assessed during the early phase of acute ischemic stroke, does not predict severity or functional outcome. © 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.

A Risk Prediction Score for Kidney Failure or Mortality in Rhabdomyolysis

PubMed Central

McMahon, Gearoid M.; Zeng, Xiaoxi; Waikar, Sushrut S.

2016-01-01

IMPORTANCE Rhabdomyolysis ranges in severity from asymptomatic elevations in creatine phosphokinase levels to a life-threatening disorder characterized by severe acute kidney injury requiring hemodialysis or continuous renal replacement therapy (RRT). OBJECTIVE To develop a risk prediction tool to identify patients at greatest risk of RRT or in-hospital mortality. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of 2371 patients admitted between January 1, 2000, and March 31, 2011, to 2 large teaching hospitals in Boston, Massachusetts, with creatine phosphokinase levels in excess of 5000 U/L within 3 days of admission. The derivation cohort consisted of 1397 patients from Massachusetts General Hospital, and the validation cohort comprised 974 patients from Brigham and Women’s Hospital. MAIN OUTCOMES AND MEASURES The composite of RRT or in-hospital mortality. RESULTS The causes and outcomes of rhabdomyolysis were similar between the derivation and validation cohorts. In total, the composite outcome occurred in 19.0% of patients (8.0% required RRT and 14.1% died during hospitalization). The highest rates of the composite outcome were from compartment syndrome (41.2%), sepsis (39.3%), and following cardiac arrest (58.5%). The lowest rates were from myositis (1.7%), exercise (3.2%), and seizures (6.0%). The independent predictors of the composite outcome were age, female sex, cause of rhabdomyolysis, and values of initial creatinine, creatine phosphokinase, phosphate, calcium, and bicarbonate. We developed a risk-prediction score from these variables in the derivation cohort and subsequently applied it in the validation cohort. The C statistic for the prediction model was 0.82 (95% CI, 0.80–0.85) in the derivation cohort and 0.83 (0.80–0.86) in the validation cohort. The Hosmer-Lemeshow P values were .14 and .28, respectively. In the validation cohort, among the patients with the lowest risk score (<5), 2.3% died or needed RRT. Among the patients with the highest risk score (>10), 61.2% died or needed RRT. CONCLUSIONS AND RELEVANCE Outcomes from rhabdomyolysis vary widely depending on the clinical context. The risk of RRT or in-hospital mortality in patients with rhabdomyolysis can be estimated using commonly available demographic, clinical, and laboratory variables on admission. PMID:24000014

A comparison of South Asian specific and established BMI thresholds for determining obesity prevalence in pregnancy and predicting pregnancy complications: findings from the Born in Bradford cohort.

PubMed

Bryant, M; Santorelli, G; Lawlor, D A; Farrar, D; Tuffnell, D; Bhopal, R; Wright, J

2014-03-01

To describe how maternal obesity prevalence varies by established international and South Asian specific body mass index (BMI) cut-offs in women of Pakistani origin and investigate whether different BMI thresholds can help to identify women at risk of adverse pregnancy and birth outcomes. Prospective bi-ethnic birth cohort study (the Born in Bradford (BiB) cohort). Bradford, a deprived city in the North of the UK. A total of 8478 South Asian and White British pregnant women participated in the BiB cohort study. Maternal obesity prevalence; prevalence of known obesity-related adverse pregnancy outcomes: mode of birth, hypertensive disorders of pregnancy (HDP), gestational diabetes, macrosomia and pre-term births. Application of South Asian BMI cut-offs increased prevalence of obesity in Pakistani women from 18.8 (95% confidence interval (CI) 17.6-19.9) to 30.9% (95% CI 29.5-32.2). With the exception of pre-term births, there was a positive linear relationship between BMI and prevalence of adverse pregnancy and birth outcomes, across almost the whole BMI distribution. Risk of gestational diabetes and HDP increased more sharply in Pakistani women after a BMI threshold of at least 30 kg m(-2), but there was no evidence of a sharp increase in any risk factors at the new, lower thresholds suggested for use in South Asian women. BMI was a good single predictor of outcomes (area under the receiver operating curve: 0.596-0.685 for different outcomes); prediction was more discriminatory and accurate with BMI as a continuous variable than as a binary variable for any possible cut-off point. Applying the new South Asian threshold to pregnant women would markedly increase those who were referred for monitoring and lifestyle advice. However, our results suggest that lowering the BMI threshold in South Asian women would not improve the predictive ability for identifying those who were at risk of adverse pregnancy outcomes.

Machine learning approach for the outcome prediction of temporal lobe epilepsy surgery.

PubMed

Armañanzas, Rubén; Alonso-Nanclares, Lidia; Defelipe-Oroquieta, Jesús; Kastanauskaite, Asta; de Sola, Rafael G; Defelipe, Javier; Bielza, Concha; Larrañaga, Pedro

2013-01-01

Epilepsy surgery is effective in reducing both the number and frequency of seizures, particularly in temporal lobe epilepsy (TLE). Nevertheless, a significant proportion of these patients continue suffering seizures after surgery. Here we used a machine learning approach to predict the outcome of epilepsy surgery based on supervised classification data mining taking into account not only the common clinical variables, but also pathological and neuropsychological evaluations. We have generated models capable of predicting whether a patient with TLE secondary to hippocampal sclerosis will fully recover from epilepsy or not. The machine learning analysis revealed that outcome could be predicted with an estimated accuracy of almost 90% using some clinical and neuropsychological features. Importantly, not all the features were needed to perform the prediction; some of them proved to be irrelevant to the prognosis. Personality style was found to be one of the key features to predict the outcome. Although we examined relatively few cases, findings were verified across all data, showing that the machine learning approach described in the present study may be a powerful method. Since neuropsychological assessment of epileptic patients is a standard protocol in the pre-surgical evaluation, we propose to include these specific psychological tests and machine learning tools to improve the selection of candidates for epilepsy surgery.

Machine Learning Approach for the Outcome Prediction of Temporal Lobe Epilepsy Surgery

PubMed Central

DeFelipe-Oroquieta, Jesús; Kastanauskaite, Asta; de Sola, Rafael G.; DeFelipe, Javier; Bielza, Concha; Larrañaga, Pedro

2013-01-01

Epilepsy surgery is effective in reducing both the number and frequency of seizures, particularly in temporal lobe epilepsy (TLE). Nevertheless, a significant proportion of these patients continue suffering seizures after surgery. Here we used a machine learning approach to predict the outcome of epilepsy surgery based on supervised classification data mining taking into account not only the common clinical variables, but also pathological and neuropsychological evaluations. We have generated models capable of predicting whether a patient with TLE secondary to hippocampal sclerosis will fully recover from epilepsy or not. The machine learning analysis revealed that outcome could be predicted with an estimated accuracy of almost 90% using some clinical and neuropsychological features. Importantly, not all the features were needed to perform the prediction; some of them proved to be irrelevant to the prognosis. Personality style was found to be one of the key features to predict the outcome. Although we examined relatively few cases, findings were verified across all data, showing that the machine learning approach described in the present study may be a powerful method. Since neuropsychological assessment of epileptic patients is a standard protocol in the pre-surgical evaluation, we propose to include these specific psychological tests and machine learning tools to improve the selection of candidates for epilepsy surgery. PMID:23646148

Attachment in medical care: A review of the interpersonal model in chronic disease management.

PubMed

Jimenez, Xavier F

2017-03-01

Objective Patient-physician interaction is continually examined in an era prioritizing patient-centered approaches, yet elaboration beyond aspects of communication and empathy is lacking. Major chronic conditions would benefit tremendously from understanding interpersonal aspects of patient-physician encounters. This review intends to provide a concise introduction to the interpersonal model of attachment theory and how it informs both the patient-physician interaction and medical outcomes in chronic care. Methods A narrative review of the theoretical, neurobiological, epidemiological, investigational, and clinical literature on attachment theory and its impact on medical outcomes was conducted, utilizing a variety of key words as searched on PubMed database. Studies and reviews included were of a variety of sources, including textbooks and peer-reviewed journals. Reports in languages other than English were excluded. Results Measurable, discrete attachment styles and behavioral patterns correlate with poor medical outcomes, including nonadherence in insecure dismissing attachment and care overutilization in insecure preoccupied attachment. Furthermore, insecure dismissing attachment is associated with significant mortality. These variables can be easily assessed, and their effects are reversible, as evidenced by collaborative care outcome data. Discussion Attachment theory is useful a model with application in clinical and investigational aspects of chronic illness care. Implications and guidelines are explored.

Early Surgical Therapy for Drug-Resistant Temporal Lobe Epilepsy

PubMed Central

Engel, Jerome; McDermott, Michael P.; Wiebe, Samuel; Langfitt, John T.; Stern, John M.; Dewar, Sandra; Sperling, Michael R.; Gardiner, Irenita; Erba, Giuseppe; Fried, Itzhak; Jacobs, Margaret; Vinters, Harry V.; Mintzer, Scott; Kieburtz, Karl

2016-01-01

Context Despite reported success, surgery for pharmacoresistant seizures is often seen as a last resort. Patients are typically referred for surgery after 20 years of seizures, often too late to avoid significant disability and premature death. Objective We sought to determine whether surgery soon after failure of 2 antiepileptic drug (AED) trials is superior to continued medical management in controlling seizures and improving quality of life (QOL). Design, Setting, and Participants The Early Randomized Surgical Epilepsy Trial (ERSET) is a multicenter, controlled, parallel-group clinical trial performed at 16 US epilepsy surgery centers. The 38 participants (18 men and 20 women; aged ≥ 12 years) had mesial temporal lobe epilepsy (MTLE) and disabling seizues for no more than 2 consecutive years following adequate trials of 2 brand-name AEDs. Eligibility for anteromesial temporal resection (AMTR) was based on a standardized presurgical evaluation protocol. Participants were randomized to continued AED treatment or AMTR 2003–2007, and observed for 2 years. Planned enrollment was 200, but the trial was halted prematurely due to slow accrual. Intervention Receipt of continued AED treatment (n=23) or a standardized AMTR plus AED treatment (n = 15). In the medical group, 7 participants underwent AMTR prior to the end of follow-up and 1 participant in the surgical group never received surgery. Main Outcome Measures The primary outcome variable was freedom from disabling seizures during year 2 of follow-up. Secondary outcome variables were health-related QOL (measured primarily by the 2-year change in the Quality of Life in Epilepsy 89 [QOLIE-89] overall T-score), cognitive function, and social adaptation. Results Zero of 23 participants in the medical group and 11 of 15 in the surgical group were seizure free during year 2 of follow-up (odds ratio=∞; 95% CI, 11.8 to ∞;P <.001). In an intention-to-treat analysis, the mean improvement in QOLIE-89 overall T-score was higher in the surgical group than in the medical group but this difference was not statistically significant (12.6 vs 4.0 points; treatment effect = 8.5; 95% CI, −1.0 to 18.1; P =.08). When data obtained after surgery from participants in the medical group were excluded, the effect of surgery on QOL was significant (12.8 vs 2.8 points; treatment effect=9.9; 95% CI, 2.2 to 17.7; P =.01). Memory decline (assessed using the Rey Auditory Verbal Learning Test) occurred in 4 participants (36%) after surgery, consistent with rates seen in the literature; but the sample was too small to permit definitive conclusions about treatment group differences in cognitive outcomes. Adverse events included a transient neurologic deficit attributed to a magnetic resonance imaging–identified postoperative stroke in a participant who had surgery and 3 cases of status epilepticus in the medical group. Conclusions Among patients with newly intractable disabling MTLE, resective surgery plus AED treatment resulted in a lower probability of seizures during year 2 of follow-up than continued AED treatment alone. Given the premature termination of the trial, the results should be interpreted with appropriate caution. PMID:22396514

Neural Network Machine Learning and Dimension Reduction for Data Visualization

NASA Technical Reports Server (NTRS)

Liles, Charles A.

2014-01-01

Neural network machine learning in computer science is a continuously developing field of study. Although neural network models have been developed which can accurately predict a numeric value or nominal classification, a general purpose method for constructing neural network architecture has yet to be developed. Computer scientists are often forced to rely on a trial-and-error process of developing and improving accurate neural network models. In many cases, models are constructed from a large number of input parameters. Understanding which input parameters have the greatest impact on the prediction of the model is often difficult to surmise, especially when the number of input variables is very high. This challenge is often labeled the "curse of dimensionality" in scientific fields. However, techniques exist for reducing the dimensionality of problems to just two dimensions. Once a problem's dimensions have been mapped to two dimensions, it can be easily plotted and understood by humans. The ability to visualize a multi-dimensional dataset can provide a means of identifying which input variables have the highest effect on determining a nominal or numeric output. Identifying these variables can provide a better means of training neural network models; models can be more easily and quickly trained using only input variables which appear to affect the outcome variable. The purpose of this project is to explore varying means of training neural networks and to utilize dimensional reduction for visualizing and understanding complex datasets.

Investigation of continuous effect modifiers in a meta-analysis on higher versus lower PEEP in patients requiring mechanical ventilation--protocol of the ICEM study.

PubMed

Kasenda, Benjamin; Sauerbrei, Willi; Royston, Patrick; Briel, Matthias

2014-05-20

Categorizing an inherently continuous predictor in prognostic analyses raises several critical methodological issues: dependence of the statistical significance on the number and position of the chosen cut-point(s), loss of statistical power, and faulty interpretation of the results if a non-linear association is incorrectly assumed to be linear. This also applies to a therapeutic context where investigators of randomized clinical trials (RCTs) are interested in interactions between treatment assignment and one or more continuous predictors. Our goal is to apply the multivariable fractional polynomial interaction (MFPI) approach to investigate interactions between continuous patient baseline variables and the allocated treatment in an individual patient data meta-analysis of three RCTs (N = 2,299) from the intensive care field. For each study, MFPI will provide a continuous treatment effect function. Functions from each of the three studies will be averaged by a novel meta-analysis approach for functions. We will plot treatment effect functions separately for each study and also the averaged function. The averaged function with a related confidence interval will provide a suitable basis to assess whether a continuous patient characteristic modifies the treatment comparison and may be relevant for clinical decision-making. The compared interventions will be a higher or lower positive end-expiratory pressure (PEEP) ventilation strategy in patients requiring mechanical ventilation. The continuous baseline variables body mass index, PaO2/FiO2, respiratory compliance, and oxygenation index will be the investigated potential effect modifiers. Clinical outcomes for this analysis will be in-hospital mortality, time to death, time to unassisted breathing, and pneumothorax. This project will be the first meta-analysis to combine continuous treatment effect functions derived by the MFPI procedure separately in each of several RCTs. Such an approach requires individual patient data (IPD). They are available from an earlier IPD meta-analysis using different methods for analysis. This new analysis strategy allows assessing whether treatment effects interact with continuous baseline patient characteristics and avoids categorization-based subgroup analyses. These interaction analyses of the present study will be exploratory in nature. However, they may help to foster future research using the MFPI approach to improve interaction analyses of continuous predictors in RCTs and IPD meta-analyses. This study is registered in PROSPERO (CRD42012003129).

CAN INFANTS BE “TAUGHT” TO ATTEND TO A NEW PHYSICAL VARIABLE IN AN EVENT CATEGORY? THE CASE OF HEIGHT IN COVERING EVENTS

PubMed Central

Wang, Su-hua; Baillargeon, Renée

2009-01-01

As they observe or produce events, infants identify variables that help them predict outcomes in each category of events. How do infants identify a new variable? An explanation-based learning (EBL) account suggests three essential steps: (1) observing contrastive outcomes relevant to the variable; (2) discovering the conditions associated with these outcomes; and (3) generating an explanation for the condition-outcome regularity discovered. In Experiments 1–3, 9-month-old infants watched events designed to “teach” them the variable height in covering events. After watching these events, designed in accord with the EBL account, the infants detected a height violation in a covering event, three months earlier than they ordinarily would have. In Experiments 4–6, the “teaching” events were modified to remove one of the EBL steps, and the infants no longer detected the height violation. The present findings thus support the EBL account and help specify the processes by which infants acquire their physical knowledge. PMID:18177635

Predicting well-being longitudinally for mothers rearing offspring with intellectual and developmental disabilities.

PubMed

Grein, K A; Glidden, L M

2015-07-01

Well-being outcomes for parents of children with intellectual and developmental disabilities (IDD) may vary from positive to negative at different times and for different measures of well-being. Predicting and explaining this variability has been a major focus of family research for reasons that have both theoretical and applied implications. The current study used data from a 23-year longitudinal investigation of adoptive and birth parents of children with IDD to determine which early child, mother and family characteristics would predict the variance in maternal outcomes 20 years after their original measurement. Using hierarchical regression analyses, we tested the predictive power of variables measured when children were 7 years old on outcomes of maternal well-being when children were 26 years old. Outcome variables included maternal self-report measures of depression and well-being. Final models of well-being accounted for 20% to 34% of variance. For most outcomes, Family Accord and/or the personality variable of Neuroticism (emotional stability/instability) were significant predictors, but some variables demonstrated a different pattern. These findings confirm that (1) characteristics of the child, mother and family during childhood can predict outcomes of maternal well-being 20 years later; and (2) different predictor-outcome relationships can vary substantially, highlighting the importance of using multiple measures to gain a more comprehensive understanding of maternal well-being. These results have implications for refining prognoses for parents and for tailoring service delivery to individual child, parent and family characteristics. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Genetic instrumental variable regression: Explaining socioeconomic and health outcomes in nonexperimental data

PubMed Central

DiPrete, Thomas A.; Burik, Casper A. P.; Koellinger, Philipp D.

2018-01-01

Identifying causal effects in nonexperimental data is an enduring challenge. One proposed solution that recently gained popularity is the idea to use genes as instrumental variables [i.e., Mendelian randomization (MR)]. However, this approach is problematic because many variables of interest are genetically correlated, which implies the possibility that many genes could affect both the exposure and the outcome directly or via unobserved confounding factors. Thus, pleiotropic effects of genes are themselves a source of bias in nonexperimental data that would also undermine the ability of MR to correct for endogeneity bias from nongenetic sources. Here, we propose an alternative approach, genetic instrumental variable (GIV) regression, that provides estimates for the effect of an exposure on an outcome in the presence of pleiotropy. As a valuable byproduct, GIV regression also provides accurate estimates of the chip heritability of the outcome variable. GIV regression uses polygenic scores (PGSs) for the outcome of interest which can be constructed from genome-wide association study (GWAS) results. By splitting the GWAS sample for the outcome into nonoverlapping subsamples, we obtain multiple indicators of the outcome PGSs that can be used as instruments for each other and, in combination with other methods such as sibling fixed effects, can address endogeneity bias from both pleiotropy and the environment. In two empirical applications, we demonstrate that our approach produces reasonable estimates of the chip heritability of educational attainment (EA) and show that standard regression and MR provide upwardly biased estimates of the effect of body height on EA. PMID:29686100

Genetic instrumental variable regression: Explaining socioeconomic and health outcomes in nonexperimental data.

PubMed

DiPrete, Thomas A; Burik, Casper A P; Koellinger, Philipp D

2018-05-29

Identifying causal effects in nonexperimental data is an enduring challenge. One proposed solution that recently gained popularity is the idea to use genes as instrumental variables [i.e., Mendelian randomization (MR)]. However, this approach is problematic because many variables of interest are genetically correlated, which implies the possibility that many genes could affect both the exposure and the outcome directly or via unobserved confounding factors. Thus, pleiotropic effects of genes are themselves a source of bias in nonexperimental data that would also undermine the ability of MR to correct for endogeneity bias from nongenetic sources. Here, we propose an alternative approach, genetic instrumental variable (GIV) regression, that provides estimates for the effect of an exposure on an outcome in the presence of pleiotropy. As a valuable byproduct, GIV regression also provides accurate estimates of the chip heritability of the outcome variable. GIV regression uses polygenic scores (PGSs) for the outcome of interest which can be constructed from genome-wide association study (GWAS) results. By splitting the GWAS sample for the outcome into nonoverlapping subsamples, we obtain multiple indicators of the outcome PGSs that can be used as instruments for each other and, in combination with other methods such as sibling fixed effects, can address endogeneity bias from both pleiotropy and the environment. In two empirical applications, we demonstrate that our approach produces reasonable estimates of the chip heritability of educational attainment (EA) and show that standard regression and MR provide upwardly biased estimates of the effect of body height on EA. Copyright © 2018 the Author(s). Published by PNAS.

How Robust Is Linear Regression with Dummy Variables?

ERIC Educational Resources Information Center

Blankmeyer, Eric

2006-01-01

Researchers in education and the social sciences make extensive use of linear regression models in which the dependent variable is continuous-valued while the explanatory variables are a combination of continuous-valued regressors and dummy variables. The dummies partition the sample into groups, some of which may contain only a few observations.…

Continuation Power Flow with Variable-Step Variable-Order Nonlinear Predictor

NASA Astrophysics Data System (ADS)

Kojima, Takayuki; Mori, Hiroyuki

This paper proposes a new continuation power flow calculation method for drawing a P-V curve in power systems. The continuation power flow calculation successively evaluates power flow solutions through changing a specified value of the power flow calculation. In recent years, power system operators are quite concerned with voltage instability due to the appearance of deregulated and competitive power markets. The continuation power flow calculation plays an important role to understand the load characteristics in a sense of static voltage instability. In this paper, a new continuation power flow with a variable-step variable-order (VSVO) nonlinear predictor is proposed. The proposed method evaluates optimal predicted points confirming with the feature of P-V curves. The proposed method is successfully applied to IEEE 118-bus and IEEE 300-bus systems.

Quantifying the process and outcomes of person-centered planning.

PubMed

Holburn, S; Jacobson, J W; Vietze, P M; Schwartz, A A; Sersen, E

2000-09-01

Although person-centered planning is a popular approach in the field of developmental disabilities, there has been little systematic assessment of its process and outcomes. To measure person-centered planning, we developed three instruments designed to assess its various aspects. We then constructed variables comprising both a Process and an Outcome Index using a combined rational-empirical method. Test-retest reliability and measures of internal consistency appeared adequate. Variable correlations and factor analysis were generally consistent with our conceptualization and resulting item and variable classifications. Practical implications for intervention integrity, program evaluation, and organizational performance are discussed.

Network Mendelian randomization: using genetic variants as instrumental variables to investigate mediation in causal pathways

PubMed Central

Burgess, Stephen; Daniel, Rhian M; Butterworth, Adam S; Thompson, Simon G

2015-01-01

Background: Mendelian randomization uses genetic variants, assumed to be instrumental variables for a particular exposure, to estimate the causal effect of that exposure on an outcome. If the instrumental variable criteria are satisfied, the resulting estimator is consistent even in the presence of unmeasured confounding and reverse causation. Methods: We extend the Mendelian randomization paradigm to investigate more complex networks of relationships between variables, in particular where some of the effect of an exposure on the outcome may operate through an intermediate variable (a mediator). If instrumental variables for the exposure and mediator are available, direct and indirect effects of the exposure on the outcome can be estimated, for example using either a regression-based method or structural equation models. The direction of effect between the exposure and a possible mediator can also be assessed. Methods are illustrated in an applied example considering causal relationships between body mass index, C-reactive protein and uric acid. Results: These estimators are consistent in the presence of unmeasured confounding if, in addition to the instrumental variable assumptions, the effects of both the exposure on the mediator and the mediator on the outcome are homogeneous across individuals and linear without interactions. Nevertheless, a simulation study demonstrates that even considerable heterogeneity in these effects does not lead to bias in the estimates. Conclusions: These methods can be used to estimate direct and indirect causal effects in a mediation setting, and have potential for the investigation of more complex networks between multiple interrelated exposures and disease outcomes. PMID:25150977

Child involvement, alliance, and therapist flexibility: process variables in cognitive-behavioural therapy for anxiety disorders in childhood.

PubMed

Hudson, Jennifer L; Kendall, Philip C; Chu, Brian C; Gosch, Elizabeth; Martin, Erin; Taylor, Alan; Knight, Ashleigh

2014-01-01

This study examined the relations between treatment process variables and child anxiety outcomes. Independent raters watched/listened to taped therapy sessions of 151 anxiety-disordered (6-14 yr-old; M = 10.71) children (43% boys) and assessed process variables (child alliance, therapist alliance, child involvement, therapist flexibility and therapist functionality) within a manual-based cognitive-behavioural treatment. Latent growth modelling examined three latent variables (intercept, slope, and quadratic) for each process variable. Child age, gender, family income and ethnicity were examined as potential antecedents. Outcome was analyzed using factorially derived clinician, mother, father, child and teacher scores from questionnaire and structured diagnostic interviews at pretreatment, posttreatment and 12-month follow-up. Latent growth models demonstrated a concave quadratic curve for child involvement and therapist flexibility over time. A predominantly linear, downward slope was observed for alliance, and functional flexibility remained consistent over time. Increased alliance, child involvement and therapist flexibility showed some albeit inconsistent, associations with positive treatment outcome. Findings support the notion that maintaining the initial high level of alliance or involvement is important for clinical improvement. There is some support that progressively increasing alliance/involvement also positively impacts on treatment outcome. These findings were not consistent across outcome measurement points or reporters. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Influences and Outcomes of Phonological Awareness: A Study of MA, PA and Auditory Processing in Pre-Readers with a Family Risk of Dyslexia

ERIC Educational Resources Information Center

Law, Jeremy M.; Wouters, Jan; Ghesquière, Pol

2017-01-01

The direct influence of phonological awareness (PA) on reading outcomes has been widely demonstrated, yet PA may also exert indirect influence on reading outcomes through other cognitive variables such as morphological awareness (MA). However, PA's own development is dependent and influenced by many extraneous variables such as auditory…

Components of a Model for Forecasting Future Status of Selected Social Indicators. Department of Education Project on Social Indicators. Technical Report No. 3.

ERIC Educational Resources Information Center

Collazo, Andres; And Others

Since a great number of variables influence future educational outcomes, forecasting possible trends is a complex task. One such model, the cross-impact matrix, has been developed. The use of this matrix in forecasting future values of social indicators of educational outcomes is described. Variables associated with educational outcomes are used…

THE STATISTICAL ANALYSIS OF DISCRETE AND CONTINUOUS OUTCOMES USING DESIRABILITY FUNCTIONS.

EPA Science Inventory

Multiple types of outcomes are sometimes measured on each animal in toxicology dose-response experiments. In this paper we introduce a method of deriving a composite score for a dose-response experiment that combines information from discrete and continuous outcomes through the ...

Removing very low-performing therapists: A simulation of performance-based retention in psychotherapy

PubMed Central

Imel, Zac E.; Sheng, Elisa; Baldwin, Scott A.; Atkins, David C.

2016-01-01

Therapists can impact the likelihood a given patient will benefit from psychotherapy. However, therapists are rarely held accountable for their patients' outcomes. As a result, low performing providers likely continue to practice alongside providers with high response rates. In the current study, we conducted a Monte Carlo simulation to illustrate a thought experiment—what happens to patient outcomes if therapists with the worst outcomes were removed from practice? We drew initial samples of 50 therapists from three simulated populations of 1,000 therapists with a mean patient response rate of 50% and different effect sizes for therapist variability in outcomes. We simulated 30 patient outcomes for each therapist, with outcome defined as response to treatment versus no response. We removed therapists with response rates in the bottom 5% and replaced them with a random sample of therapists from the population. Over 10 years, the difference in responses between the lowest and highest performing therapists was substantial (between 697 and 997 additional responses to treatment). After repeatedly removing the lowest performing providers 40 times (simulating a 10 year time span), response rates increased substantially. The cumulative number of patient responses (i.e., summing the total number of responses across 10 years) increased by 4266, 6404, and 9307 when therapists accounted for 5%, 10%, or 20% of the patient outcome variance, respectively. These findings indicate that performance-based retention of therapists could improve the quality of psychotherapy in health systems by improving the average response rate and decreasing the probability that a patient will be treated by a therapist who has little chance of helping. PMID:26301424

Serum potassium, mortality, and kidney outcomes in the Atherosclerosis Risk in Communities (ARIC) Study

PubMed Central

Chen, Yan; Chang, Alex R.; McAdams DeMarco, Mara A.; Inker, Lesley A.; Matsushita, Kunihiro; Ballew, Shoshana H.; Coresh, Josef; Grams, Morgan E.

2017-01-01

Objectives To investigate the association between serum potassium, mortality, and kidney outcomes in the general population and whether potassium-altering medications modify these associations. Patients and Methods We studied 15,539 adults in the Atherosclerosis Risk in Communities (ARIC) study. Cox proportional hazard regression was used to investigate the association of serum potassium at baseline (1987–1989), evaluated categorically (hypokalemia, <3.5 mmol/L; normokalemia, ≥3.5 and < 5.5 mmol/L; hyperkalemia, ≥5.5 mmol/L) and continuously using linear spline terms (knots at 3.5 and 5.5 mmol/L), with mortality, sudden cardiac death (SCD), incident chronic kidney disease (CKD), and end-stage renal disease (ESRD). The end date of follow up for all outcomes was December 31, 2012. We also evaluated whether classes of potassium-altering medications modified the association between serum potassium and adverse outcomes. Results Overall, 2.7% of the participants had hypokalemia and 2.1% had hyperkalemia. In a fully adjusted model, hyperkalemia was significantly associated with mortality (HR: 1.24; 95% CI: 1.04–1.49) but not SCD, CKD, or ESRD. Hypokalemia as a categorical variable was not associated with any outcome; however, associations of hypokalemia with all-cause mortality and kidney outcomes were observed among those who were not taking potassium-wasting diuretics (all P for interaction <.001). Conclusions Higher values of serum potassium were associated with higher risk of mortality in the general population. Lower levels of potassium were associated with adverse kidney outcomes and mortality among participants not taking potassium-wasting diuretics. PMID:27499535

BIVARIATE MODELLING OF CLUSTERED CONTINUOUS AND ORDERED CATEGORICAL OUTCOMES. (R824757)

EPA Science Inventory

Simultaneous observation of continuous and ordered categorical outcomes for each subject is common in biomedical research but multivariate analysis of the data is complicated by the multiple data types. Here we construct a model for the joint distribution of bivariate continuous ...

Continuing Care and Trauma in Women Offenders’ Substance Use, Psychiatric Status, and Self-Efficacy Outcomes

PubMed Central

Saxena, Preeta; Grella, Christine E.; Messina, Nena P.

2015-01-01

Using secondary data analysis of 3 separate trauma-informed treatment programs for women offenders, we examine outcomes between those who received both prison and community-based substance abuse treatment (i.e., continuing care; n = 85) and those who received either prison or community aftercare treatment (n = 108). We further account for differences in trauma exposure to examine whether continuing care moderates this effect on substance use, psychiatric severity, and self-efficacy outcomes at follow-up. The main effect models of continuing care showed a significant association with high psychiatric status and did not yield significant associations with substance use or self-efficacy. However, the interaction between trauma history and continuing care showed significant effects on all 3 outcomes. Findings support the importance of a continuing care treatment model for women offenders exposed to multiple forms of traumatic events, and provide evidence of the effectiveness of integrating trauma-informed treatment into women’s substance abuse treatment. PMID:26924891

Hydration level is an internal variable for computing motivation to obtain water rewards in monkeys.

PubMed

Minamimoto, Takafumi; Yamada, Hiroshi; Hori, Yukiko; Suhara, Tetsuya

2012-05-01

In the process of motivation to engage in a behavior, valuation of the expected outcome is comprised of not only external variables (i.e., incentives) but also internal variables (i.e., drive). However, the exact neural mechanism that integrates these variables for the computation of motivational value remains unclear. Besides, the signal of physiological needs, which serves as the primary internal variable for this computation, remains to be identified. Concerning fluid rewards, the osmolality level, one of the physiological indices for the level of thirst, may be an internal variable for valuation, since an increase in the osmolality level induces drinking behavior. Here, to examine the relationship between osmolality and the motivational value of a water reward, we repeatedly measured the blood osmolality level, while 2 monkeys continuously performed an instrumental task until they spontaneously stopped. We found that, as the total amount of water earned increased, the osmolality level progressively decreased (i.e., the hydration level increased) in an individual-dependent manner. There was a significant negative correlation between the error rate of the task (the proportion of trials with low motivation) and the osmolality level. We also found that the increase in the error rate with reward accumulation can be well explained by a formula describing the changes in the osmolality level. These results provide a biologically supported computational formula for the motivational value of a water reward that depends on the hydration level, enabling us to identify the neural mechanism that integrates internal and external variables.

Variable reporting of functional outcomes and return to play in superior labrum anterior and posterior tear.

PubMed

Steinhaus, Michael E; Makhni, Eric C; Lieber, Adam C; Kahlenberg, Cynthia A; Gulotta, Lawrence V; Romeo, Anthony A; Verma, Nikhil N

2016-11-01

Outcomes assessments after superior labrum anterior and posterior (SLAP) tear/repair are highly varied, making it difficult to draw comparisons across the literature. This study examined the inconsistency in outcomes reporting in the SLAP tear literature. We hypothesize that there is significant variability in outcomes reporting and that although most studies may report return to play, time to return reporting will be highly variable. The PubMed, Medline, Scopus, and Embase databases were systematically reviewed for studies from January 2000 to December 2014 reporting outcomes after SLAP tear/repair. Two reviewers assessed each study, and those meeting inclusion criteria were examined for pertinent data. Outcomes included objective (range of motion, strength, clinical examinations, and imaging) and subjective (patient-reported outcomes, satisfaction, activities of daily living, and return to play) measures. Of the 56 included studies, 43% documented range of motion, 14% reported strength, and 16% noted postoperative imaging. There was significant variation in use of patient-reported outcomes measures, with the 3 most commonly noted measures reported in 20% to 55% of studies. Return to play was noted in 75% of studies, and 23% reported time to return, with greater rates in elite athletes. Eleven studies (20%) did not report follow-up or noted data with <12 months of follow-up. The SLAP literature is characterized by substantial variability in outcomes reporting, with time to return to play noted in few studies. Efforts to standardize outcomes reporting would facilitate comparisons across the literature and improve our understanding of the prognosis of this injury. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

The relationship between preoperative general mental health and postoperative quality of life in minimally invasive lumbar spine surgery.

PubMed

Asher, Rachel; Mason, Ashley E; Weiner, Joseph; Fessler, Richard G

2015-06-01

In assessing poor lumbar surgery outcomes, researchers continue to investigate psychosocial predictors of patient postoperative quality of life. This is the first study of its kind to investigate this relationship in an exclusively minimally invasive patient sample. To determine the association between preoperative mental health and postoperative patient-centered outcomes in patients undergoing minimally invasive lumbar surgery. In 83 adults undergoing single-level minimally invasive lumbar spine surgery, Pearson correlation and partial correlation analyses were conducted between all demographic and clinical baseline variables and Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and 36-item Short-Form Health Survey Version 2.0 (SF-36v2) scores at 6 to 12 months postoperatively. SF-36v2 mental component summary scores (MCS) were used to assess pre- and postoperative general mental health. Post hoc analysis consisted of Pearson correlations between baseline SF-36v2, ODI, and VAS scores, and an identical set of correlations at outcomes. Preoperative MCS showed no significant association with outcomes VAS, ODI, or physical component summary scores. Baseline disability correlated significantly and more strongly with baseline MCS (P < .001, r = -0.40) than baseline pain levels (VAS back not significant, VAS leg P = .015, r = 0.27). Outcomes disability correlated significantly and more strongly with outcome back and leg pain levels (P < .001, r = 0.60 and 0.66) than outcome MCS (P = .031, r = -0.24). In a patient sample with mental health scores comparable to the population mean, there is no relationship between preoperative general mental health and postoperative patient-centered outcomes. Surgeons should consider the dynamic relationships between patient disability, mental health, and pain levels in assessing quality of life at different time points.

Does the thyroid-stimulating hormone measured concurrently with first trimester biochemical screening tests predict adverse pregnancy outcomes occurring after 20 weeks gestation?

PubMed

Ong, Gregory S Y; Hadlow, Narelle C; Brown, Suzanne J; Lim, Ee Mun; Walsh, John P

2014-12-01

Maternal hypothyroidism in early pregnancy is associated with adverse outcomes, but not consistently across studies. First trimester screening for chromosomal anomalies is routine in many centers and provides an opportunity to test thyroid function. To determine if thyroid function tests performed with first trimester screening predicts adverse pregnancy outcomes. A cohort study of 2411 women in Western Australia with singleton pregnancies attending first trimester screening between 9 and 14 weeks gestation. We evaluated the association between TSH, free T4, free T3, thyroid antibodies, free beta human chorionic gonadotrophin (β-hCG) and pregnancy associated plasma protein A (PAPP-A) with a composite of adverse pregnancy events as the primary outcome. Secondary outcomes included placenta previa, placental abruption, pre-eclampsia, pregnancy loss after 20 weeks gestation, threatened preterm labor, preterm birth, small size for gestational age, neonatal death, and birth defects. TSH exceeded the 97.5th percentile for the first trimester (2.15 mU/L) in 133 (5.5%) women, including 22 (1%) with TSH above the nonpregnant reference range (4 mU/L) and 5 (0.2%) above 10 mU/L. Adverse outcomes occurred in 327 women (15%). TSH and free T4 did not differ significantly between women with or without adverse pregnancy events. On the multivariate analysis, neither maternal TSH >2.15 mU/L nor TSH as a continuous variable predicted primary or secondary outcomes. Testing maternal TSH as part of first trimester screening does not predict adverse pregnancy outcomes. This may be because in the community setting, mainly mild abnormalities in thyroid function are detected.

Consideration of What May Influence Student Outcomes on Alternate Assessment.

ERIC Educational Resources Information Center

Browder, Diane M.; Fallin, Kathy; Davis, Stephanie; Karvonen, Meagan

2003-01-01

This article describes variables that may influence alternate assessment outcomes for students with disabilities and offers recommendations to enhance student achievement. These variables include technical quality, curriculum access, data collection, instructional effectiveness, risk factors, and resources allocated to instruction. Two of four…

Using statistical process control methods to trace small changes in perinatal mortality after a training program in a low-resource setting.

PubMed

Mduma, Estomih R; Ersdal, Hege; Kvaloy, Jan Terje; Svensen, Erling; Mdoe, Paschal; Perlman, Jeffrey; Kidanto, Hussein Lessio; Soreide, Eldar

2018-05-01

To trace and document smaller changes in perinatal survival over time. Prospective observational study, with retrospective analysis. Labor ward and operating theater at Haydom Lutheran Hospital in rural north-central Tanzania. All women giving birth and birth attendants. Helping Babies Breathe (HBB) simulation training on newborn care and resuscitation and some other efforts to improve perinatal outcome. Perinatal survival, including fresh stillbirths and early (24-h) newborn survival. The variable life-adjusted plot and cumulative sum chart revealed a steady improvement in survival over time, after the baseline period. There were some variations throughout the study period, and some of these could be linked to different interventions and events. To our knowledge, this is the first time statistical process control methods have been used to document changes in perinatal mortality over time in a rural Sub-Saharan hospital, showing a steady increase in survival. These methods can be utilized to continuously monitor and describe changes in patient outcomes.

Cumulative Disadvantage and Youth Well-Being: A Multi-Domain Examination with Life Course Implications

PubMed Central

Nurius, Paula S.; Prince, Dana M.; Rocha, Anita

2015-01-01

Purpose The accumulation of disadvantage has been shown to increase psychosocial stressors that impact life course well-being. This study tests for significant differences, based on disadvantage exposure, on youths’ emotional and physical health, as well as family supports, peer assets, and academic success, which hold potential for resilience and amelioration of negative health outcomes. Methods A 12 item cumulative disadvantage summed index derived from surveys of a racially and socioeconomically diverse sample of urban high school seniors (n=9,658) was used to distinguish youth at low, moderate, and high levels. Results Findings supported hypothesized stepped patterns such that as multiple disadvantages accumulate, a concomitant decline is evident across the assessed outcome variables (except positive academic identity). Post-hoc tests indicated a pattern of groups being significantly different from one another. Discussion Overall, results lend support for an additive stress load associated with stacked disadvantage, with implications for continuing trends into adulthood as well as preventive interventions PMID:26617431

Continuous-variable quantum authentication of physical unclonable keys

NASA Astrophysics Data System (ADS)

Nikolopoulos, Georgios M.; Diamanti, Eleni

2017-04-01

We propose a scheme for authentication of physical keys that are materialized by optical multiple-scattering media. The authentication relies on the optical response of the key when probed by randomly selected coherent states of light, and the use of standard wavefront-shaping techniques that direct the scattered photons coherently to a specific target mode at the output. The quadratures of the electromagnetic field of the scattered light at the target mode are analysed using a homodyne detection scheme, and the acceptance or rejection of the key is decided upon the outcomes of the measurements. The proposed scheme can be implemented with current technology and offers collision resistance and robustness against key cloning.

A brief introduction to probability.

PubMed

Di Paola, Gioacchino; Bertani, Alessandro; De Monte, Lavinia; Tuzzolino, Fabio

2018-02-01

The theory of probability has been debated for centuries: back in 1600, French mathematics used the rules of probability to place and win bets. Subsequently, the knowledge of probability has significantly evolved and is now an essential tool for statistics. In this paper, the basic theoretical principles of probability will be reviewed, with the aim of facilitating the comprehension of statistical inference. After a brief general introduction on probability, we will review the concept of the "probability distribution" that is a function providing the probabilities of occurrence of different possible outcomes of a categorical or continuous variable. Specific attention will be focused on normal distribution that is the most relevant distribution applied to statistical analysis.

Pediatric Minor Head Injury 2.0: Moving from Injury Exclusion to Risk Stratification.

PubMed

Homme, James Jim L

2018-05-01

Visits for pediatric minor blunt head trauma continue to increase. Variability exists in clinician evaluation and management of this generally low-risk population. Clinical decision rules identify very low-risk children who can forgo neuroimaging. Observation before imaging decreases neuroimaging rates. Outcome data can be used to risk stratify children into more discrete categories. Decision aids improves knowledge and accuracy of risk perception and facilitates identification of caregiver preferences, allowing for shared decision making. For children in whom imaging is performed and is normal or shows isolated linear skull fractures, deterioration and neurosurgical intervention are rare and hospital admission can be avoided. Copyright © 2018 The Author. Published by Elsevier Inc. All rights reserved.

Variations on an Expectancy-Value Model of Motivation in Science.

PubMed

DeBacker; Nelson

1999-04-01

Relationships among motivational variables from goal theory and expectancy-value theory were investigated in this correlational study of high school students. Self-report surveys of motivation in science were collected during biology classes from 69 males and 80 females. Outcome measures were effort, persistence, and achievement. Gender differences were noted in the pattern of zero-order correlations. Internal motivation variables were related to achievement in males but not females. Regression analyses indicated that the motivation variables explained large proportions of variance in the outcomes. However, the contribution of individual variables differed by gender. Most notable was perceived ability, which contributed significantly to predicting outcome measures for females but not males. Findings suggest that interventions may need to focus on different motivational aspects depending on gender. Copyright 1999 Academic Press.

Artificial Neural Network System to Predict the Postoperative Outcome of Percutaneous Nephrolithotomy.

PubMed

Aminsharifi, Alireza; Irani, Dariush; Pooyesh, Shima; Parvin, Hamid; Dehghani, Sakineh; Yousofi, Khalilolah; Fazel, Ebrahim; Zibaie, Fatemeh

2017-05-01

To construct, train, and apply an artificial neural network (ANN) system for prediction of different outcome variables of percutaneous nephrolithotomy (PCNL). We calculated predictive accuracy, sensitivity, and precision for each outcome variable. During the study period, all adult patients who underwent PCNL at our institute were enrolled in the study. Preoperative and postoperative variables were recorded, and stone-free status was assessed perioperatively with computed tomography scans. MATLAB software was used to design and train the network in a feed forward back-propagation error adjustment scheme. Preoperative and postoperative data from 200 patients (training set) were used to analyze the effect and relative relevance of preoperative values on postoperative parameters. The validated adequately trained ANN was used to predict postoperative outcomes in the subsequent 254 adult patients (test set) whose preoperative values were serially fed into the system. To evaluate system accuracy in predicting each postoperative variable, predicted values were compared with actual outcomes. Two hundred fifty-four patients (155 [61%] males) were considered the test set. Mean stone burden was 6702.86 ± 381.6 mm 3 . Overall stone-free rate was 76.4%. Fifty-four out of 254 patients (21.3%) required ancillary procedures (shockwave lithotripsy 5.9%, transureteral lithotripsy 10.6%, and repeat PCNL 4.7%). The accuracy and sensitivity of the system in predicting different postoperative variables ranged from 81.0% to 98.2%. As a complex nonlinear mathematical model, our ANN system is an interconnected data mining tool, which prospectively analyzes and "learns" the relationships between variables. The accuracy and sensitivity of the system for predicting the stone-free rate, the need for blood transfusion, and post-PCNL ancillary procedures ranged from 81.0% to 98.2%.The stone burden and the stone morphometry were among the most significant preoperative characteristics that affected all postoperative outcome variables and they received the highest relative weight by the ANN system.

Testing Components of a Self-Management Theory in Adolescents With Type 1 Diabetes Mellitus.

PubMed

Verchota, Gwen; Sawin, Kathleen J

The role of self-management in adolescents with type 1 diabetes mellitus is not well understood. The purpose of the research was to examine the relationship of key individual and family self-management theory, context, and process variables on proximal (self-management behaviors) and distal (hemoglobin A1c and diabetes-specific health-related quality of life) outcomes in adolescents with type 1 diabetes. A correlational, cross-sectional study was conducted to identify factors contributing to outcomes in adolescents with Type 1 diabetes and examine potential relationships between context, process, and outcome variables delineated in individual and family self-management theory. Participants were 103 adolescent-parent dyads (adolescents ages 12-17) with Type 1 diabetes from a Midwest, outpatient, diabetes clinic. The dyads completed a self-report survey including instruments intended to measure context, process, and outcome variables from individual and family self-management theory. Using hierarchical multiple regression, context (depressive symptoms) and process (communication) variables explained 37% of the variance in self-management behaviors. Regimen complexity-the only significant predictor-explained 11% of the variance in hemoglobin A1c. Neither process variables nor self-management behaviors were significant. For the diabetes-specific health-related quality of life outcome, context (regimen complexity and depressive symptoms) explained 26% of the variance at step 1; an additional 9% of the variance was explained when process (self-efficacy and communication) variables were added at step 2; and 52% of the variance was explained when self-management behaviors were added at Step 3. In the final model, three variables were significant predictors: depressive symptoms, self-efficacy, and self-management behaviors. The individual and family self-management theory can serve as a cogent theory for understanding key concepts, processes, and outcomes essential to self-management in adolescents and families dealing with Type 1 diabetes mellitus.

Pediatric extracorporeal shock wave lithotripsy: Predicting successful outcomes.

PubMed

McAdams, Sean; Shukla, Aseem R

2010-10-01

Extracorporeal shock wave lithotripsy (ESWL) is currently a first-line procedure of most upper urinary tract stones <2 cm of size because of established success rates, its minimal invasiveness and long-term safety with minimal complications. Given that alternative surgical and endourological options exist for the management of stone disease and that ESWL failure often results in the need for repeat ESWL or secondary procedures, it is highly desirable to identify variables predicting successful outcomes of ESWL in the pediatric population. Despite numerous reports and growing experience, few prospective studies and guidelines for pediatric ESWL have been completed. Variation in the methods by which study parameters are measured and reported can make it difficult to compare individual studies or make definitive recommendations. There is ongoing work and a need for continuing improvement of imaging protocols in children with renal colic, with a current focus on minimizing exposure to ionizing radiation, perhaps utilizing advancements in ultrasound and magnetic resonance imaging. This report provides a review of the current literature evaluating the patient attributes and stone factors that may be predictive of successful ESWL outcomes along with reviewing the role of pre-operative imaging and considerations for patient safety.

Size and distance are perceived independently in an optical tunnel: Evidence for direct perception.

PubMed

Kim, Seokhun; Carello, Claudia; Turvey, Michael T

2016-08-01

The historical but questionable size-distance invariance hypothesis (SDIH) features computation over geometric, oculomotor, and binocular cues and the coupling of percepts-perceived size, S', is mediated by perceived distance, D'. A contemporary non-mediational hypothesis holds that S' and D' are specific to distinct optical variables. We report two experiments with an optical tunnel, an arrangement of alternating black and white concentric rings, that allows systematic manipulation of the optic array at a point of observation while controlling a variety of size and depth cues. Participants viewed targets of different sizes at different distances monocularly, reporting S' and D' via magnitude production. In Experiment 1, the target was either placed in a continuous tunnel (extending 164cm) or in a tunnel that truncated at the target's location. Experiment 2 included a third tunnel, one that was truncated with a flat depiction of the posterior surface structure that would have been visible in the continuous tunnel. In both experiments, S' decreased with D but D' was unaffected by S. Partial correlation analyses showed that the relationship between S' and D' was not significant when the contributions of other variables were removed. Importantly, S' and D' were affected differently by manipulations of the optical tunnel's continuity while computationally obvious visual cues were controlled. These outcomes suggest that D' is not a mediator of S'. Rather S' and D' are independently determined with correlated but different optical bases, results that support the direct model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Health status: does it predict choice in further education?

PubMed Central

Koivusilta, L; Rimpelä, A; Rimpelä, M

1995-01-01

STUDY OBJECTIVE--To study the significance of a young person's health to his or her choice of further education at age 16. DESIGN--A cross sectional population survey SETTING--The whole of Finland. PARTICIPANTS--A representative sample of 2977 Finnish 16 year olds. The response rate was 83%. MEASUREMENTS AND MAIN RESULTS--The three outcome variables reflected successive steps on the way to educational success: school attendance after the completion of compulsory schooling, the type of school, and school achievement for those at school. Continuing their education and choosing upper secondary school were most typical of young people from upper social classes. Female gender and living with both parents increased the probability of choosing to go on to upper secondary school. Over and above these background variables, some health factors had additional explanatory power. Continuing their education, attending upper secondary schools, and good achievement were typical of those who considered their health to be good. Chronically ill adolescents were more likely to continue their education than the healthy ones. CONCLUSIONS--School imposes great demands on young people, thus revealing differences in personal health resources. Adaptation to the norms of a society in which education is highly valued is related to satisfying health status. In a welfare state that offers equal educational opportunities for everyone, however, chronically ill adolescents can add to their resources for coping through schooling. Health related selection thus works differently for various indicators of health and in various kinds of societies. Social class differences in health in the future may be more dependent on personally experienced health problems than on medically diagnosed diseases. PMID:7798039

An opinion-driven behavioral dynamics model for addictive behaviors

DOE PAGES

Moore, Thomas W.; Finley, Patrick D.; Apelberg, Benjamin J.; ...

2015-04-08

We present a model of behavioral dynamics that combines a social network-based opinion dynamics model with behavioral mapping. The behavioral component is discrete and history-dependent to represent situations in which an individual’s behavior is initially driven by opinion and later constrained by physiological or psychological conditions that serve to maintain the behavior. Additionally, individuals are modeled as nodes in a social network connected by directed edges. Parameter sweeps illustrate model behavior and the effects of individual parameters and parameter interactions on model results. Mapping a continuous opinion variable into a discrete behavioral space induces clustering on directed networks. Clusters providemore » targets of opportunity for influencing the network state; however, the smaller the network the greater the stochasticity and potential variability in outcomes. Furthermore, this has implications both for behaviors that are influenced by close relationships verses those influenced by societal norms and for the effectiveness of strategies for influencing those behaviors.« less

Characteristics and Proximal Outcomes of Calls Made to Suicide Crisis Hotlines in California.

PubMed

Ramchand, Rajeev; Jaycox, Lisa; Ebener, Pat; Gilbert, Mary Lou; Barnes-Proby, Dionne; Goutam, Prodyumna

2017-01-01

Suicide hotlines are commonly used to prevent suicides, although centers vary with respect to their management and operations. To describe variability across suicide prevention hotlines. Live monitoring of 241 calls was conducted at 10 suicide prevention hotlines in California. Call centers are similar with respect to caller characteristics and the concerns callers raise during their calls. The proportion of callers at risk for suicide varied from 3 to 57%. Compliance with asking about current suicide risk, past ideation, and past attempts also ranged considerably. Callers to centers that were part of the National Suicide Prevention Lifeline (NSPL) were more likely to experience reduced distress than callers to centers that were not part of the NSPL. Because callers do not generally choose the center or responder that will take their call, it is critical to promote quality across call centers and minimize the variability that currently exists. Accrediting bodies, funders, and crisis centers should require that centers continuously monitor calls to ensure and improve call quality.

A conceptual model for site-level ecology of the giant gartersnake (Thamnophis gigas) in the Sacramento Valley, California

USGS Publications Warehouse

Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.; Hansen, Eric C.; Scherer, Rick D.; Patterson, Laura C.

2015-08-14

Bayesian networks further provide a clear visual display of the model that facilitates understanding among various stakeholders (Marcot and others, 2001; Uusitalo , 2007). Empirical data and expert judgment can be combined, as continuous or categorical variables, to update knowledge about the system (Marcot and others, 2001; Uusitalo , 2007). Importantly, Bayesian network models allow inference from causes to consequences, but also from consequences to causes, so that data can inform the states of nodes (values of different random variables) in either direction (Marcot and others, 2001; Uusitalo , 2007). Because they can incorporate both decision nodes that represent management actions and utility nodes that quantify the costs and benefits of outcomes, Bayesian networks are ideally suited to risk analysis and adaptive management (Nyberg and others, 2006; Howes and others, 2010). Thus, Bayesian network models are useful in situations where empirical data are not available, such as questions concerning the responses of giant gartersnakes to management.

Food Security Under Shifting Economic, Demographic, and Climatic Conditions (Invited)

NASA Astrophysics Data System (ADS)

Naylor, R. L.

2013-12-01

Global demand for food, feed, and fuel will continue to rise in a more populous and affluent world. Meeting this demand in the future will become increasingly challenging with global climate change; when production shocks stemming from climate variability are added to the new mean climate state, food markets could become more volatile. This talk will focus on the interacting market effects of demand and supply for major food commodities, with an eye on climate-related supply trends and shocks. Lessons from historical patterns of climate variability (e.g., ENSO and its global teleconnections) will be used to infer potential food security outcomes in the event of abrupt changes in the mean climate state. Domestic food and trade policy responses to crop output and price volatility in key producing and consuming nations, such as export bans and import tariffs, will be discussed as a potentially major destabilizing force, underscoring the important influence of uncertainty in achieving--or failing to achieve--food security.

Self-efficacy, physical activity, and aerobic fitness in middle school children: examination of a pedometer intervention program.

PubMed

Manley, Dana; Cowan, Patricia; Graff, Carolyn; Perlow, Michael; Rice, Pamela; Richey, Phyllis; Sanchez, Zoila

2014-01-01

Physical activity in children has been associated with a number of health benefits. Unfortunately, physical inactivity continues to increase. The purpose of this study was to examine the relationships among self-efficacy levels, physical activity, aerobic fitness, and body composition (relative body mass index [RBMI]) and to determine whether a school-based pedometer intervention program would improve those variables. The sample consisted of 116 rural 11- to 13-year-old students. Weakly positive correlations between self-efficacy, physical activity, and aerobic fitness and weakly correlated inverse relationships between self-efficacy, physical activity, aerobic fitness and RBMI were found. There was no statistical significance between the intervention and control group when analyzing outcome variables. These findings suggest that those with optimal RBMI levels have higher self-efficacy, physical activity and aerobic fitness levels. Although not statistically significant, the intervention group had greater improvements in mean self-efficacy scores, aerobic fitness levels, and RBMI. © 2014.

Smooth time-dependent receiver operating characteristic curve estimators.

PubMed

Martínez-Camblor, Pablo; Pardo-Fernández, Juan Carlos

2018-03-01

The receiver operating characteristic curve is a popular graphical method often used to study the diagnostic capacity of continuous (bio)markers. When the considered outcome is a time-dependent variable, two main extensions have been proposed: the cumulative/dynamic receiver operating characteristic curve and the incident/dynamic receiver operating characteristic curve. In both cases, the main problem for developing appropriate estimators is the estimation of the joint distribution of the variables time-to-event and marker. As usual, different approximations lead to different estimators. In this article, the authors explore the use of a bivariate kernel density estimator which accounts for censored observations in the sample and produces smooth estimators of the time-dependent receiver operating characteristic curves. The performance of the resulting cumulative/dynamic and incident/dynamic receiver operating characteristic curves is studied by means of Monte Carlo simulations. Additionally, the influence of the choice of the required smoothing parameters is explored. Finally, two real-applications are considered. An R package is also provided as a complement to this article.

Risk-Sensitivity in Sensorimotor Control

PubMed Central

Braun, Daniel A.; Nagengast, Arne J.; Wolpert, Daniel M.

2011-01-01

Recent advances in theoretical neuroscience suggest that motor control can be considered as a continuous decision-making process in which uncertainty plays a key role. Decision-makers can be risk-sensitive with respect to this uncertainty in that they may not only consider the average payoff of an outcome, but also consider the variability of the payoffs. Although such risk-sensitivity is a well-established phenomenon in psychology and economics, it has been much less studied in motor control. In fact, leading theories of motor control, such as optimal feedback control, assume that motor behaviors can be explained as the optimization of a given expected payoff or cost. Here we review evidence that humans exhibit risk-sensitivity in their motor behaviors, thereby demonstrating sensitivity to the variability of “motor costs.” Furthermore, we discuss how risk-sensitivity can be incorporated into optimal feedback control models of motor control. We conclude that risk-sensitivity is an important concept in understanding individual motor behavior under uncertainty. PMID:21283556

Clinical outcomes and frontal plane two-dimensional biomechanics during the 30-second single leg stance test in patients before and after hip abductor tendon reconstructive surgery.

PubMed

Huxtable, Rose E; Ackland, Timothy R; Janes, Gregory C; Ebert, Jay R

2017-07-01

Hip abductor tendon tears are a common cause of Greater Trochanteric Pain Syndrome. Conservative treatments are often ineffective and surgical reconstruction may be recommended. This study investigated the improvement in clinical outcomes and frontal plane two-dimensional biomechanics during a 30-second single leg stance test, in patients undergoing reconstruction. We hypothesized that clinical scores and pertinent biomechanical variables would significantly improve post-surgery, and these outcomes would be significantly correlated. Twenty-one patients with symptomatic tendon tears underwent reconstruction. Patients were evaluated pre-surgery, and at 6 and 12months post-surgery, using patient-reported outcome measures, assessment of hip abductor strength and six-minute walk capacity. Frontal plane, two-dimensional, biomechanical variables including pelvis-on-femur angle, pelvic drop, trunk lean and lateral pelvic shift, were evaluated throughout a 30-second single leg stance test. ANOVA evaluated outcomes over time, while Pearson's correlations investigated associations between clinical scores, pain, functional and biomechanical outcome variables. While clinical and functional measures significantly improved (P<0.05) over time, no significant group differences (P>0.05) were observed in biomechanical variables from pre- to post-surgery. While five patients displayed a positive Trendelenburg sign pre-surgery, only one was positive post-surgery. Clinical outcomes and biomechanical variables during the single leg stance test were not correlated. Despite improvements in clinical and functional measures over time, biomechanical changes during a weight bearing single leg stance test were not significantly different following tendon repair. Follow up beyond 12months may be required, whereby symptomatic relief may precede functional and biomechanical improvement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Resource savings and outcomes associated with outpatient laparoscopic appendectomy for nonperforated appendicitis.

PubMed

Gurien, Lori A; Burford, Jeffrey M; Bonasso, Patrick C; Dassinger, Melvin S

2017-11-01

Postoperative admission for acute appendicitis utilizes health care system resources. We evaluated outcomes and hospital charges for children with nonperforated appendicitis who underwent outpatient laparoscopic appendectomy. A retrospective chart review was performed for patients ≤18years old who underwent laparoscopic appendectomy for acute appendicitis in 2015. Patients were categorized into discharge from postanesthesia care unit (PACU) (outpatient), admission for <24-h, and admission for >24-h. Continuous variables were compared using analysis of variance and categorical variables were compared using chi-square test, with p<0.05 considered significant. Of the 171 patients identified, 63 (37%) were discharged from the PACU, 94 (55%) were admitted <24-h, and 14 (8%) were admitted >24-h. There were no differences in postoperative emergency department/clinic visits, complications, or readmissions. Hospital charges for admission <24-h and >24-h were $1007 and $2237 more per patient than the PACU-discharge group, respectively. Outpatient laparoscopic appendectomies became more common over time, occurring in only 20% of patients with acute appendicitis in the first quarter of the year versus 49% of patients in the last quarter. Outpatient laparoscopic appendectomy for nonperforated appendicitis in children is a safe practice that decreases length of stay and hospital charges. Adoption of an outpatient strategy allows for better standardization of care and can lead to savings in health care resources. III (Treatment: retrospective comparative study). Copyright © 2017 Elsevier Inc. All rights reserved.

The Power of Continuity in Graduate Teacher Education Master's Programmes

ERIC Educational Resources Information Center

Molseed, Timothy R.

2009-01-01

The intentional development of continuity as it applies to programme structure, themes and outcomes is examined for their power in providing a coherent circular connection between the philosophy, operation, assessment and outcomes of a graduate teacher education programme. It is argued that the intentional development of programme continuity will…

Testing quantum contextuality of continuous-variable states

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

McKeown, Gerard; Paternostro, Mauro; Paris, Matteo G. A.

2011-06-15

We investigate the violation of noncontextuality by a class of continuous-variable states, including variations of entangled coherent states and a two-mode continuous superposition of coherent states. We generalize the Kochen-Specker (KS) inequality discussed by Cabello [A. Cabello, Phys. Rev. Lett. 101, 210401 (2008)] by using effective bidimensional observables implemented through physical operations acting on continuous-variable states, in a way similar to an approach to the falsification of Bell-Clauser-Horne-Shimony-Holt inequalities put forward recently. We test for state-independent violation of KS inequalities under variable degrees of state entanglement and mixedness. We then demonstrate theoretically the violation of a KS inequality for anymore » two-mode state by using pseudospin observables and a generalized quasiprobability function.« less

Cutoff Finder: A Comprehensive and Straightforward Web Application Enabling Rapid Biomarker Cutoff Optimization

PubMed Central

Budczies, Jan; Klauschen, Frederick; Sinn, Bruno V.; Győrffy, Balázs; Schmitt, Wolfgang D.; Darb-Esfahani, Silvia; Denkert, Carsten

2012-01-01

Gene or protein expression data are usually represented by metric or at least ordinal variables. In order to translate a continuous variable into a clinical decision, it is necessary to determine a cutoff point and to stratify patients into two groups each requiring a different kind of treatment. Currently, there is no standard method or standard software for biomarker cutoff determination. Therefore, we developed Cutoff Finder, a bundle of optimization and visualization methods for cutoff determination that is accessible online. While one of the methods for cutoff optimization is based solely on the distribution of the marker under investigation, other methods optimize the correlation of the dichotomization with respect to an outcome or survival variable. We illustrate the functionality of Cutoff Finder by the analysis of the gene expression of estrogen receptor (ER) and progesterone receptor (PgR) in breast cancer tissues. This distribution of these important markers is analyzed and correlated with immunohistologically determined ER status and distant metastasis free survival. Cutoff Finder is expected to fill a relevant gap in the available biometric software repertoire and will enable faster optimization of new diagnostic biomarkers. The tool can be accessed at http://molpath.charite.de/cutoff. PMID:23251644

CAN'T MISS--conquer any number task by making important statistics simple. Part 1. Types of variables, mean, median, variance, and standard deviation.

PubMed

Hansen, John P

2003-01-01

Healthcare quality improvement professionals need to understand and use inferential statistics to interpret sample data from their organizations. In quality improvement and healthcare research studies all the data from a population often are not available, so investigators take samples and make inferences about the population by using inferential statistics. This three-part series will give readers an understanding of the concepts of inferential statistics as well as the specific tools for calculating confidence intervals for samples of data. This article, Part 1, presents basic information about data including a classification system that describes the four major types of variables: continuous quantitative variable, discrete quantitative variable, ordinal categorical variable (including the binomial variable), and nominal categorical variable. A histogram is a graph that displays the frequency distribution for a continuous variable. The article also demonstrates how to calculate the mean, median, standard deviation, and variance for a continuous variable.

Dynamic Latent Trait Models with Mixed Hidden Markov Structure for Mixed Longitudinal Outcomes.

PubMed

Zhang, Yue; Berhane, Kiros

2016-01-01

We propose a general Bayesian joint modeling approach to model mixed longitudinal outcomes from the exponential family for taking into account any differential misclassification that may exist among categorical outcomes. Under this framework, outcomes observed without measurement error are related to latent trait variables through generalized linear mixed effect models. The misclassified outcomes are related to the latent class variables, which represent unobserved real states, using mixed hidden Markov models (MHMM). In addition to enabling the estimation of parameters in prevalence, transition and misclassification probabilities, MHMMs capture cluster level heterogeneity. A transition modeling structure allows the latent trait and latent class variables to depend on observed predictors at the same time period and also on latent trait and latent class variables at previous time periods for each individual. Simulation studies are conducted to make comparisons with traditional models in order to illustrate the gains from the proposed approach. The new approach is applied to data from the Southern California Children Health Study (CHS) to jointly model questionnaire based asthma state and multiple lung function measurements in order to gain better insight about the underlying biological mechanism that governs the inter-relationship between asthma state and lung function development.

Maternal physical activity mode and fetal heart outcome.

PubMed

May, Linda E; Suminski, Richard R; Berry, Andrew; Langaker, Michelle D; Gustafson, Kathleen M

2014-07-01

Maternal leisure-time physical activity (LTPA) improves cardiac autonomic function in the fetus. The specific physical activity attributes (e.g., mode) that produce this benefit are not well understood. To determine if more time spent performing non-continuous LTPA during pregnancy is significantly associated with lower fetal heart rate (HR) and increased heart rate variability (HRV). This paper presents a retrospective analysis of previously reported data. Fetal magnetocardiograms (MCG) were recorded from 40 pregnant women at 36-wk gestational age. Metrics of fetal HR and HRV, self-reported min of continuous and non-continuous LTPA performed during the 3-months preceding the 36-wk assessment point and covariates (maternal weight change pre to 36-wk, age, and resting HR and fetal activity state during MCG recordings. Positive correlations were significant (p<0.05) between min of continuous LTPA, the time domain metrics that describe fetal overall HRV, short-term HRV and a frequency domain metric that reflects vagal activity. Time spent in non-continuous LTPA was positively correlated (p<0.05) with two HRV metrics that reflect fetal overall HRV. In the multiple regression analyses, minutes of non-continuous LTPA remained associated with fetal vagal activity (p<0.05) and the relationships between minutes of non-continuous LTPA and fetal overall HRV (p<0.005) persisted. These data suggest non-continuous physical activity provides unique benefits to the fetal autonomic nervous system that may give the fetus an adaptive advantage. Further studies are needed to understand the physiological mechanisms and long-term health effects of physical activity (both non-continuous and continuous) performed during pregnancy to both women and their offspring. Copyright © 2014 Elsevier Ltd. All rights reserved.

Virtual continuity of measurable functions and its applications

NASA Astrophysics Data System (ADS)

Vershik, A. M.; Zatitskii, P. B.; Petrov, F. V.

2014-12-01

A classical theorem of Luzin states that a measurable function of one real variable is `almost' continuous. For measurable functions of several variables the analogous statement (continuity on a product of sets having almost full measure) does not hold in general. The search for a correct analogue of Luzin's theorem leads to a notion of virtually continuous functions of several variables. This apparently new notion implicitly appears in the statements of embedding theorems and trace theorems for Sobolev spaces. In fact it reveals the nature of such theorems as statements about virtual continuity. The authors' results imply that under the conditions of Sobolev theorems there is a well-defined integration of a function with respect to a wide class of singular measures, including measures concentrated on submanifolds. The notion of virtual continuity is also used for the classification of measurable functions of several variables and in some questions on dynamical systems, the theory of polymorphisms, and bistochastic measures. In this paper the necessary definitions and properties of admissible metrics are recalled, several definitions of virtual continuity are given, and some applications are discussed. Bibliography: 24 titles.

Early Breastfeeding Problems Mediate the Negative Association between Maternal Obesity and Exclusive Breastfeeding at 1 and 2 Months Postpartum1–3

PubMed Central

O’Sullivan, Elizabeth J; Perrine, Cria G; Rasmussen, Kathleen M

2015-01-01

Background Compared with normal-weight women, women with obesity experience poorer breastfeeding outcomes. Successful breastfeeding among women with obesity is important for achieving national breastfeeding goals. Objectives The objectives were to determine whether the negative association between obesity and any or exclusive breastfeeding at 1 and 2 mo postpartum is mediated through breastfeeding problems that occur in the first 2 wk postpartum and if this association differs by parity. Methods Mothers (1151 normal-weight and 580 obese) in the Infant Feeding Practices Study II provided information on sociodemographic and psychosocial characteristics, body mass index, and breastfeeding outcomes. At 1 mo postpartum, participants reported the breastfeeding problems they experienced in the first 2 wk postpartum from a predefined list of 17 options. We used factor analysis to condense these problems into 4 explanatory variables; continuous factor scores were computed for use in further analyses. We used maximum likelihood logistic regression to assess mediation of the association between obesity and breastfeeding outcomes through early breastfeeding problems. Results No significant effect of obesity was found on any breastfeeding at 1 or 2 mo. At 1 mo postpartum, for both primiparous and multiparous women, there was a significant direct effect of obesity on exclusive breastfeeding and a significant indirect effect of obesity through early breastfeeding problems related to the explanatory mediating variable “Insufficient Milk” (throughout the remainder of the Abstract, this factor will be denoted by upper case notation). At 2 mo postpartum both the direct effect of obesity and the indirect effect through Insufficient Milk were significant in primiparous women but only the indirect effect remained significant in multiparous women. Conclusions Early problems related to Insufficient Milk may partially explain the association between obesity and poor exclusive breastfeeding outcomes. Women who are obese, particularly those reporting breastfeeding problems that grouped in the Insufficient Milk factor in the early postpartum period, may benefit from additional breastfeeding support. PMID:26290005

Therapeutic effect of erythropoietin in patients with traumatic brain injury: a meta-analysis of randomized controlled trials.

PubMed

Liu, Wen-Chao; Wen, Liang; Xie, Tao; Wang, Hao; Gong, Jiang-Biao; Yang, Xiao-Feng

2017-07-01

OBJECTIVE Erythropoietin (EPO) exerts a neuroprotective effect in animal models of traumatic brain injury (TBI). However, its effectiveness in human patients with TBI is unclear. In this study, the authors conducted the first meta-analysis to assess the effectiveness and safety of EPO in patients with TBI. METHODS In December 2015, a systematic search was performed of PubMed, Web of Science, MEDLINE, Embase, the Cochrane Library databases, and Google Scholar. Only English-language publications of randomized controlled trials (RCTs) using EPO in patients with TBI were selected for analysis. The assessed outcomes included mortality, favorable neurological outcome, hospital stay, and associated adverse effects. Continuous variables were presented as mean difference (MD) with a 95% confidence interval (CI). Dichotomous variables were presented as risk ratio (RR) or risk difference (RD) with a 95% CI. Statistical heterogeneity was examined using both I 2 and chi-square tests. RESULTS Of the 346 studies identified in the search, 5 RCTs involving 915 patients met the inclusion criteria. The overall results demonstrated that EPO significantly reduced mortality (RR 0.69, 95% CI 0.49-0.96, p = 0.03) and shortened the hospitalization time (MD -7.59, 95% CI -9.71 to -5.46, p < 0.0001) for patients with TBI. Pooled results of favorable outcome (RR 1.00, 95% CI 0.88-1.15, p = 0.97) and deep vein thrombosis (DVT; RD 0.00, 95% CI -0.05 to 0.05, p = 1.00) did not show a significant difference. CONCLUSIONS The authors suggested that EPO is beneficial for patients with TBI in terms of reducing mortality and shortening hospitalization time without increasing the risk of DVT. However, its effect on improving favorable neurological outcomes did not reach statistical significance. Therefore, more well-designed RCTs are necessary to ascertain the optimum dosage and time window of EPO treatment for patients with TBI.

Does Increased Body Mass Index Influence Outcomes After Rotator Cuff Repair?

PubMed

Kessler, Katie E; Robbins, Christopher B; Bedi, Asheesh; Carpenter, James E; Gagnier, Joel J; Miller, Bruce S

2018-03-01

To investigate the influence of pre-existing obesity (body mass index [BMI] ≥ 30) on outcomes after rotator cuff repair surgery. We collected data on adult patients who underwent surgical repair for symptomatic full-thickness rotator cuff tears confirmed by imaging between 2012 and 2015. The required follow-up was 3 years. At baseline and 6, 12, 24, and 36 months, the American Shoulder and Elbow Surgeons score, Western Ontario Rotator Cuff index, and visual analog scale pain scores were collected. Complications were assessed by a chart review. Obesity was defined as BMI ≥ 30. Chi-square analysis and Student's t-test examined differences between categorical and continuous variables at baseline. Generalized estimating equations examined the effects of fixed factors on outcome variables longitudinally from baseline to 36 months. Thirty-nine percent of 213 subjects were obese (mean BMI = 29.2; range, 16-48; standard deviation, 5.8). There were no statistically significant differences between obese and nonobese subjects in other baseline characteristics. When controlling for covariates, obese subjects reported no differences in Western Ontario Rotator Cuff, American Shoulder and Elbow Surgeons, or visual analog scale pain scores when compared with nonobese subjects at baseline and over 3 years from surgery. Although obese patients were more likely to have inpatient surgery, there was no difference in the incidence of postoperative complications. Contrary to our hypothesis, obese participants who underwent rotator cuff repair reported no difference in functional outcome or pain scores compared with nonobese participants over 3 years. In addition, obesity was not associated with postoperative complications in this study. However, as we hypothesized, obese participants were more likely than nonobese participants to have repair in the inpatient setting. Level III, retrospective comparative study. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Clinical outcomes of isolated renal failure compared to other forms of organ failure in patients with severe acute pancreatitis.

PubMed

Gougol, Amir; Dugum, Mohannad; Dudekula, Anwar; Greer, Phil; Slivka, Adam; Whitcomb, David C; Yadav, Dhiraj; Papachristou, Georgios I

2017-08-07

To assess differences in clinical outcomes of isolated renal failure (RF) compared to other forms of organ failure (OF) in patients with severe acute pancreatitis (SAP). Using a prospectively maintained database of patients with acute pancreatitis admitted to a tertiary medical center between 2003 and 2016, those with evidence of persistent OF were classified to renal, respiratory, cardiovascular, or multi-organ (2 or more organs). Data regarding demographics, comorbidities, etiology of acute pancreatitis, and clinical outcomes were prospectively recorded. Differences in clinical outcomes after development of isolated RF in comparison to other forms of OF were determined using independent t and Mann-Whitney U tests for continues variables, and χ 2 test for discrete variables. Among 500 patients with acute pancreatitis, 111 patients developed persistent OF: mean age was 54 years, and 75 (67.6%) were male. Forty-three patients had isolated OF: 17 (15.3%) renal, 25 (21.6%) respiratory, and 1 (0.9%) patient with cardiovascular failure. No differences in demographics, etiology of acute pancreatitis, systemic inflammatory response syndrome scores, or development of pancreatic necrosis were seen between patients with isolated RF vs isolated respiratory failure. Patients with isolated RF were less likely to require nutritional support (76.5% vs 96%, P = 0.001), ICU admission (58.8% vs 100%, P = 0.001), and had shorter mean ICU stay (2.4 d vs 15.7 d, P < 0.001), compared to isolated respiratory failure. None of the patients with isolated RF or isolated respiratory failure died. Among patients with SAP per the Revised Atlanta Classification, approximately 15% develop isolated RF. This subgroup seems to have a less protracted clinical course compared to other forms of OF. Isolated RF might be weighed less than isolated respiratory failure in risk predictive modeling of acute pancreatitis.

Contribution of physician assistants/associates to secondary care: a systematic review.

PubMed

Halter, Mary; Wheeler, Carly; Pelone, Ferruccio; Gage, Heather; de Lusignan, Simon; Parle, Jim; Grant, Robert; Gabe, Jonathan; Nice, Laura; Drennan, Vari M

2018-06-19

To appraise and synthesise research on the impact of physician assistants/associates (PA) in secondary care, specifically acute internal medicine, care of the elderly, emergency medicine, trauma and orthopaedics, and mental health. Systematic review. Electronic databases (Medline, Embase, ASSIA, CINAHL, SCOPUS, PsycINFO, Social Policy and Practice, EconLit and Cochrane), reference lists and related articles. Peer-reviewed articles of any study design, published in English, 1995-2017. Blinded parallel processes were used to screen abstracts and full text, data extractions and quality assessments against published guidelines. A narrative synthesis was undertaken. Impact on: patients' experiences and outcomes, service organisation, working practices, other professional groups and costs. 5472 references were identified and 161 read in full; 16 were included-emergency medicine (7), trauma and orthopaedics (6), acute internal medicine (2), mental health (1) and care of the elderly (0). All studies were observational, with variable methodological quality. In emergency medicine and in trauma and orthopaedics, when PAs are added to teams, reduced waiting and process times, lower charges, equivalent readmission rate and good acceptability to staff and patients are reported. Analgesia prescribing, operative complications and mortality outcomes were variable. In internal medicine outcomes of care provided by PAs and doctors were equivalent. PAs have been deployed to increase the capacity of a team, enabling gains in waiting time, throughput, continuity and medical cover. When PAs were compared with medical staff, reassuringly there was little or no negative effect on health outcomes or cost. The difficulty of attributing cause and effect in complex systems where work is organised in teams is highlighted. Further rigorous evaluation is required to address the complexity of the PA role, reporting on more than one setting, and including comparison between PAs and roles for which they are substituting. CRD42016032895. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Outcome Probability versus Magnitude: When Waiting Benefits One at the Cost of the Other

PubMed Central

Young, Michael E.; Webb, Tara L.; Rung, Jillian M.; McCoy, Anthony W.

2014-01-01

Using a continuous impulsivity and risk platform (CIRP) that was constructed using a video game engine, choice was assessed under conditions in which waiting produced a continuously increasing probability of an outcome with a continuously decreasing magnitude (Experiment 1) or a continuously increasing magnitude of an outcome with a continuously decreasing probability (Experiment 2). Performance in both experiments reflected a greater desire for a higher probability even though the corresponding wait times produced substantive decreases in overall performance. These tendencies are considered to principally reflect hyperbolic discounting of probability, power discounting of magnitude, and the mathematical consequences of different response rates. Behavior in the CIRP is compared and contrasted with that in the Balloon Analogue Risk Task (BART). PMID:24892657

Comparison of outcomes and other variables between conference abstracts and subsequent peer-reviewed papers involving pre-harvest or abattoir-level interventions against foodborne pathogens.

PubMed

Snedeker, Kate G; Campbell, Mollie; Totton, Sarah C; Guthrie, Alessia; Sargeant, Jan M

2010-11-01

Accuracy in the reporting of studies in conference abstracts is important because the majority of studies in such abstracts are never further detailed in peer-reviewed publications, and data from such abstracts may be used in systematic reviews. Previous research on interventional studies in human biomedicine indicates that there is no guarantee of consistency between a conference abstract and paper in the reporting of results and other key variables. However, no research has been done to determine if this lack of reporting consistency in abstracts and papers extends to interventional studies in pre-harvest/harvest-level food safety. The goal of this study was to compare outcome results and other key variables between conference abstracts and subsequent peer-reviewed publications describing studies of pre-harvest and abattoir-level interventions against foodborne pathogens, and to determine whether the agreement in the results or key variables was associated with the time to full publication. A systematic search identified 59 conference abstracts with matching peer-reviewed papers (matches), and data on variables including outcome measures and results, pathogens, species, interventions, overall efficacy of intervention, sample size and housing were extracted from both the conference abstracts and the papers. The matching of variables between abstracts and papers was described, and logistic regression used to test for associations between variable matching and time to publication. Sample size was only provided for both abstract and paper in 24 matches; the same sample size was reported in 20 of these matches. Most other variables were reported in the majority of abstracts/papers, and with the exception of outcomes and intervention effect, the reporting of variables was relatively consistent. There was no significant difference in the numbers of authors, with the first author the same in 78.3% of matches. Of 231 outcome measures reported in both abstracts and papers, nearly one third (77% or 32.2%) had different results, with 32 changing direction of effect. More than a quarter of matches involved at least one significant change in outcome result. The overall conclusion on the efficacy of the intervention changed in 10.7% of matches. There was a significant association between increased time to publication and differences in the number of authors, and having fewer outcome measures in the abstract reported in the paper. These results suggest that data from conference abstracts should be considered with caution. Copyright © 2010 Elsevier B.V. All rights reserved.

Sample Size Limits for Estimating Upper Level Mediation Models Using Multilevel SEM

ERIC Educational Resources Information Center

Li, Xin; Beretvas, S. Natasha

2013-01-01

This simulation study investigated use of the multilevel structural equation model (MLSEM) for handling measurement error in both mediator and outcome variables ("M" and "Y") in an upper level multilevel mediation model. Mediation and outcome variable indicators were generated with measurement error. Parameter and standard…

Family, Community, and Educational Outcomes in South Asia

ERIC Educational Resources Information Center

Chudgar, Amita; Shafiq, M. Najeeb

2010-01-01

In this article, we review research on the economics and sociology of education to assess the relationships between family and community variables and children's educational outcomes in South Asia. At the family level, we examine the variables of family socioeconomic status (SES), parental education, family structure, and religion and caste. At…

Culture-Specific Variables That May Affect Employment Outcomes for Mexican-American Youth with Disabilities.

ERIC Educational Resources Information Center

Meier-Kronick, Nancy

This paper reviews variables specific to the Mexican-American culture that might influence work-related behavior and outcomes for youths with disabilities from this population. Areas covered include: parental/family network; cultural view of disability; religious influences; acculturation levels; language issues; education and employment…

Controlled assessment of the efficacy of occlusal stabilization splints on sleep bruxism.

PubMed

van der Zaag, Jacques; Lobbezoo, Frank; Wicks, Darrel J; Visscher, Corine M; Hamburger, Hans L; Naeije, Machiel

2005-01-01

To assess the efficacy of occlusal stabilization splints in the management of sleep bruxism (SB) in a double-blind, parallel, controlled, randomized clinical trial. Twenty-one participants were randomly assigned to an occlusal splint group (n = 11; mean age = 34.2 +/- 13.1 years) or a palatal splint (ie, an acrylic palatal coverage) group (n = 10; mean age = 34.9 +/- 11.2 years). Two polysomnographic recordings that included bilateral masseter electromyographic activity were made: one prior to treatment, the other after a treatment period of 4 weeks. The number of bruxism episodes per hour of sleep (Epi/h), the number of bursts per hour (Bur/h), and the bruxism time index (ie, the percentage of total sleep time spent bruxing) were established as outcome variables at a 10% maximum voluntary contraction threshold level. A general linear model was used to test both the effects between splint groups and within the treatment phase as well as their interaction for each outcome variable. Neither occlusal stabilization splints nor palatal splints had an influence on the SB outcome variables or on the sleep variables measured on a group level. In individual cases, variable outcomes were found: Some patients had an increase (33% to 48% of the cases), while others showed no change (33% to 48%) or a decrease (19% to 29%) in SB outcome variables. The absence of significant group effects of splints in the management of SB indicates that caution is required when splints are indicated, apart from their role in the protection against dental wear. The application of splints should therefore be considered at the individual patient level.

Standardised outcomes in nephrology - Haemodialysis (SONG-HD): study protocol for establishing a core outcome set in haemodialysis.

PubMed

Tong, Allison; Manns, Braden; Hemmelgarn, Brenda; Wheeler, David C; Tugwell, Peter; Winkelmayer, Wolfgang C; van Biesen, Wim; Crowe, Sally; Kerr, Peter G; Polkinghorne, Kevan R; Howard, Kirsten; Pollock, Carol; Hawley, Carmel M; Johnson, David W; McDonald, Stephen P; Gallagher, Martin P; Urquhart-Secord, Rachel; Craig, Jonathan C

2015-08-19

Chronic kidney disease is a significant contributor to mortality and morbidity worldwide, and the number of people who require dialysis or transplantation continues to increase. People on dialysis are 15 times more likely to die than the general population. Dialysis is also costly, intrusive, and time-consuming and imposes an enormous burden on patients and their families. This escalating problem has spurred a proliferation of trials in dialysis, yet health and quality of life remain poor. The reasons for this are complex and varied but are attributable in part to problems in the design and reporting of studies, particularly outcome selection. Problems related to outcomes include use of unvalidated surrogates, outcomes of little or no relevance to patients, highly variable outcome selection limiting comparability across studies, and bias in reporting outcomes. The aim of the Standardised Outcomes in Nephrology-Haemodialysis (SONG-HD) study is to establish a core outcome set for haemodialysis trials, to improve the quality of reporting, and the relevance of trials conducted in people on haemodialysis. SONG-HD is a five-phase project that includes the following: a systematic review to identify outcomes that have been reported in haemodialysis systematic reviews and trials; nominal group technique with patients and caregivers to identify, rank, and describe reasons for their choices; qualitative stakeholder interviews with patients, caregivers, clinicians, researchers, and policy makers to elicit individual values and perspectives on outcomes for haemodialysis trials; a three-round Delphi survey with stakeholder groups to distil and generate a prioritised list of core outcomes; and a consensus workshop to establish a core outcome set for haemodialysis trials. Establishing a core outcome set to be consistently measured and reported in haemodialysis trials will improve the integrity, transparency, usability, and contribution of research relevant to patients requiring haemodialysis; ensure that outcomes of relevance to all stakeholders are consistently reported across trials; and mitigate against outcome reporting bias. Ultimately, patients will be more protected from potential harm, patients and clinicians will be better able to make informed decisions about treatment, and researchers and policy makers will be more able to maximise the value of research to the public.

Body dysmorphic disorder: prevalence and outcomes in an oculofacial plastic surgery practice.

PubMed

Woolley, Austin J; Perry, Julian D

2015-06-01

To determine the prevalence, associated factors, and surgical outcomes of patients with body dysmorphic disorder in an oculofacial surgery practice. Retrospective cross-sectional analysis of a consecutive case series. Participants consisted of a consecutive series of 728 patients who completed the Dysmorphic Concern Questionnaire in an oculofacial surgery practice at The Cole Eye Institute between November 2013 and June 2014. A questionnaire score ≥9 was used as a positive screen for body dysmorphic disorder. Three control patients scoring ≤8 in the same month were randomly selected for each positive-screening patient. Main outcome measures included number of reoperations, surgical complications, and follow-up visits; preoperative and postoperative pain scores; and the technician word count. Categorical variables were analyzed with Pearson χ(2) tests or Fisher exact tests, while continuous variables were analyzed with Wilcoxon rank sum tests or t tests. A total of 728 patients completed the questionnaire and 50 (6.9%) scored 9 or more. Using a confidence interval of 95%, patients in the positive questionnaire screen group were younger (P = .004), had more eyelid surgeries (P = .007), experienced higher rates of complications after surgery (P = .002), reported higher postoperative pain scores (P = .034), required more reoperations (P = .050), and had a higher technician word count compared to the control group (P = .003). The prevalence of body dysmorphic disorder in an oculofacial surgical setting matches reports from other surgical specialties, and is significantly higher than in the general population. Patients screening positively for body dysmorphic disorder tend to have higher postoperative pain scores and more postoperative complications. Copyright © 2015 Elsevier Inc. All rights reserved.

Lowest Glucose Variability and Hypoglycemia Are Observed With the Combination of a GLP-1 Receptor Agonist and Basal Insulin (VARIATION Study).

PubMed

Bajaj, Harpreet S; Venn, Karri; Ye, Chenglin; Patrick, Avril; Kalra, Shivani; Khandwala, Hasnain; Aslam, Nadeem; Twum-Barima, David; Aronson, Ronnie

2017-02-01

There is a dearth of published literature comparing glucose variability (GV) between different insulin regimens in type 2 diabetes. This cohort study compares GV using continuous glucose monitoring (CGM) in patients with well-controlled type 2 diabetes using four common insulin regimens: basal insulin + oral drugs (BO), basal insulin + glucagon-like peptide 1 receptor agonist (GLP-1 RA) (BGLP), premixed insulin (PM), and basal-bolus insulin (BB). Consecutive patients from three endocrinology clinics who met study criteria-type 2 diabetes, age 18 to 80 years, BMI ≤ 45 kg/m 2 , stable insulin regimen for a minimum of 6 months, and stable A1C value ≤7.5% (58 mmol/mol) before study enrollment-underwent 6-day masked CGM. Hypoglycemia was defined as a sensor glucose concentration <70 mg/dL on CGM. A total of 160 patients with comparable baseline characteristics formed four equal insulin regimen cohorts. The daily glucose SD (the primary outcome) was significantly lower in the BGLP cohort versus the BO, PM, and BB cohorts (P = 0.03, P = 0.01, and P < 0.01, respectively), and remained so after adjusting for age, BMI, type 2 diabetes duration, and A1C. Similarly, daily hypoglycemia outcomes on CGM were least for the BGLP cohort. The lowest GV and lowest hypoglycemia were observed in patients using the combination of basal insulin with a GLP-1 RA, supporting the complementary glycemic action of these agents in type 2 diabetes. These observed benefits in GV and hypoglycemia may contribute to the cardiovascular outcome reduction seen with GLP-1 RA therapy and should be investigated further. © 2017 by the American Diabetes Association.

Mexican Americans Receive Less Intensive Stroke Rehabilitation Than Non-Hispanic Whites.

PubMed

Morgenstern, Lewis B; Sais, Emma; Fuentes, Michael; Ifejika, Nneka L; Jiang, Xiaqing; Horn, Susan D; Case, Erin; Lisabeth, Lynda D

2017-06-01

Mexican Americans (MAs) have worse neurological, functional, and cognitive outcomes after stroke. Stroke rehabilitation is important for good outcome. In a population-based study, we sought to determine whether allocation of stroke rehabilitation services differed by ethnicity. Patients with stroke were identified as part of the Brain Attack Surveillance in Corpus Christi (BASIC) project, TX, USA. Cases were validated by physicians using source documentation. Patients were followed prospectively for 3 months after stroke to determine rehabilitation services and transitions. Descriptive statistics were used to depict the study population. Continuous baseline variables were compared using 2 sample t tests or Wilcoxon rank-sum tests by ethnicity. Categorical baseline variables were compared using χ 2 tests. Ethnic comparisons of rehabilitation services were compared using χ 2 tests, Fisher's exact tests, and logistic regression. Seventy-two subjects (50 MA and 22 non-Hispanic white [NHW]) were followed. Mean age, NHW-69 (SD 13), MA-66 (SD 11) years, sex (NHW 55% male, MA 50% male) and median presenting National Institutes of Health Stroke Scale did not differ significantly. There were no ethnic differences among the proportion of patients who were sent home without any rehabilitation services ( P =0.9). Among those who received rehabilitation, NHWs were more likely to get inpatient rehabilitation (73%) compared with MAs (30%), P =0.016. MAs (51%) were much more likely to receive home rehabilitation services compared with NHWs (0%) ( P =0.0017). In this population-based study, MAs were more likely to receive home-based rehabilitation, whereas NHWs were more likely to get inpatient rehabilitation. This disparity may, in part, explain the worse stroke outcome in MAs. © 2017 American Heart Association, Inc.

Evaluation of an intervention to reduce adolescent sitting time during the school day: The 'Stand Up for Health' randomised controlled trial.

PubMed

Parrish, Anne-Maree; Trost, Stewart G; Howard, Steven J; Batterham, Marijka; Cliff, Dylan; Salmon, Jo; Okely, Anthony D

2018-05-22

Adolescents spend large proportions of the school day sitting; potentially increasing their health risks. This study aimed to evaluate the feasibility, acceptability and potential efficacy of a school-based intervention to reduce adolescent sitting time during the school day. Two-arm parallel-group randomised controlled trial. Adolescents (13-16 years) were recruited from four private high schools in New South Wales, Australia. Schools were pair-matched and randomised to treatment or control. Research assistants were blinded to intervention aims and treatment allocation. Intervention initiatives included classroom and outdoor environmental measures to break up and reduce the proportion of adolescent school time spent sitting. Teacher and students surveys assessed intervention feasibility, acceptability and potential efficacy. Proportional sitting time was the primary outcome, measured by activPAL monitors, worn for one week during the school day. Secondary outcomes included body mass index, body fatness, working memory and non-verbal reasoning. Data were analysed using a general linear model for continuous variables and adjusted for clustering. While teachers and students supported the program, process evaluation results indicate aspects of the intervention were not implemented with fidelity. Eighty-eight adolescents (M age =14.7±0.7, 50% male) participated in the trial. Eighty-six had valid data for all variables (43 controls, 43 intervention). There was no significant intervention effect on the primary outcome. There was a significant effect on working memory (adjusted difference ±SD=-0.42±1.37; p=0.048 (Cohen's d)=0.31). These findings contribute to limited research in this area, providing guidance for future interventions in the high school environment. The study was registered with the Australian and New Zealand Clinical Trials Registry (ACTRN 12614001001684). Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Clinical features and prognosis of paraquat poisoning: a review of 41 cases

PubMed Central

Delirrad, Mohammad; Majidi, Mohammad; Boushehri, Behzad

2015-01-01

Purpose: Paraquat is a contact herbicide which is highly toxic to human. Deliberate self-poisoning with paraquat continues to be a major public health concern in many developing countries. This study aimed to evaluate the data on cases of acute paraquat poisoning and to compare different variables between survivors and non-survivors. Methods: In this cross sectional study, medical records of all paraquat intoxicated patients were reviewed at Taleghani hospital of Urmia, Iran, from 2007 to 2013, retrospectively. Demographics, clinical features and laboratory findings were evaluated. The variables compared between survivors and non-survivors were the amount of paraquat ingested, occurrence of vomiting after ingestion, time and place of hospital admission, length of hospital stay, leukocytosis, serum creatinine level and the outcomes. Results: A total of 41 patients were evaluated. The mean ± standard deviation of patients’ age were 31.6±16.9 years. The Length of hospital stay was 5.75±4.6 days. Most poisonings occurred in spring and summer. The in-hospital fatality rate was 46.3%. Statistically significant associations were found between the outcome of patients and the amount ingested (P=0.001), vomiting (P=0.004), early need to intensive cares (P=0.009), leukocytosis (P=0.001), serum creatinine levels (P=0.001), manifestations of acute hepatic (P<0.001) and respiratory failure (P=0.007). Conclusion: Ingestion of more than 30 ml, prompt vomiting, early need to intensive cares, leukocytosis, and multi-organ failures are major determinants for fatal outcome of paraquat poisoning. It may be useful to educate health professionals and the general population about the serious consequences of exposure to paraquat. PMID:26221379

[Psychiatric complications of abortion].

PubMed

Gurpegui, Manuel; Jurado, Dolores

2009-01-01

The psychiatric consequences of induced abortion continue to be the object of controversy. The reactions of women when they became aware of conception are very variable. Pregnancy, whether initially intended or unintended, may provoke stress; and miscarriage may bring about feelings of loss and grief reaction. Therefore, induced abortion, with its emotional implications (of relief, shame and guilt) not surprisingly is a stressful adverse life event. METHODOLOGICAL CONSIDERATIONS: There is agreement among researchers on the need to compare the mental health outcomes (or the psychiatric complications) with appropriate groups, including women with unintended pregnancies ending in live births and women with miscarriages. There is also agreement on the need to control for the potential confounding effects of multiple variables: demographic, contextual, personal development, previous or current traumatic experiences, and mental health prior to the obstetric event. Any psychiatric outcome is multi-factorial in origin and the impact of life events depend on how they are perceived, the psychological defence mechanisms (unconscious to a great extent) and the coping style. The fact of voluntarily aborting has an undeniable ethical dimension in which facts and values are interwoven. No research study has found that induced abortion is associated with a better mental health outcome, although the results of some studies are interpreted as or Some general population studies point out significant associations with alcohol or illegal drug dependence, mood disorders (including depression) and some anxiety disorders. Some of these associations have been confirmed, and nuanced, by longitudinal prospective studies which support causal relationships. With the available data, it is advisable to devote efforts to the mental health care of women who have had an induced abortion. Reasons of the woman's mental health by no means can be invoked, on empirical bases, for inducing an abortion.

High transverse skin incisions may reduce wound complications in obese women having cesarean sections: a pilot study.

PubMed

Walton, Robert B; Shnaekel, Kelsey L; Ounpraseuth, Songthip T; Napolitano, Peter G; Magann, Everett F

2017-11-01

Women having cesarean section have a high risk of wound complications. Our objective was to determine whether high transverse skin incisions are associated with a reduced risk of cesarean wound complications in women with BMI greater than 40. A retrospective cohort study was undertaken of parturients ages 18-45 with BMI greater than 40 having high transverse skin incisions from January 2010 to April 2015 at a tertiary maternity hospital. Temporally matched controls had low transverse skin incisions along with a BMI greater than 40. The primary outcome, wound complication, was defined as any seroma, hematoma, dehiscence, or infection requiring opening and evacuating/debriding the wound. Secondary outcomes included rates of endometritis, number of hospital days, NICU admission, Apgar scores, birth weight, and gestational age at delivery. Analysis of outcomes was performed using two-sample t-test or Wilcoxon rank-sum test for continuous variables and Fisher's exact test for categorical variables. Thirty-two women had high transverse incisions and were temporally matched with 96 controls (low transverse incisions). The mean BMI was 49 for both groups. There was a trend toward reduced wound complications in those having high transverse skin incisions, but this did not reach statistical significance (15.63% versus 27.08%, p = .2379). Those having high transverse skin incisions had lower five minute median Apgar scores (8.0 versus 9.0, p = .0021), but no difference in umbilical artery pH values. The high transverse group also had increased NICU admissions (28.13% versus 5.21%, p = .0011), and early gestational age at delivery (36.8 versus 38.0, p = .0272). High transverse skin incisions may reduce the risk of wound complications in parturients with obesity. A study with more power should be considered.

Patient Characteristics and Outcomes After Hemorrhagic Stroke in Pregnancy.

PubMed

Leffert, Lisa R; Clancy, Caitlin R; Bateman, Brian T; Cox, Margueritte; Schulte, Phillip J; Smith, Eric E; Fonarow, Gregg C; Schwamm, Lee H; Kuklina, Elena V; George, Mary G

2015-10-01

Hospitalizations for pregnancy-related stroke are rare but increasing. Hemorrhagic stroke (HS), ie, subarachnoid hemorrhage and intracerebral hemorrhage, is more common than ischemic stroke in pregnant versus nonpregnant women, reflecting different phenotypes or risk factors. We compared stroke risk factors and outcomes in pregnant versus nonpregnant HS in the Get With The Guidelines-Stroke Registry. Using medical history or International Classification of Diseases-Ninth Revision codes, we identified 330 pregnant and 10 562 nonpregnant female patients aged 18 to 44 years with HS in Get With The Guidelines-Stroke (2008-2014). Differences in patient and care characteristics were compared by χ(2) or Fisher exact test (categorical variables) or Wilcoxon rank-sum (continuous variables) tests. Conditional logistic regression assessed the association of pregnancy with outcomes conditional on categorical age and further adjusted for patient and hospital characteristics. Pregnant versus nonpregnant HS patients were younger with fewer pre-existing stroke risk factors and medications. Pregnant versus nonpregnant subarachnoid hemorrhage patients were less impaired at arrival, and less than half met blood pressure criteria for severe preeclampsia. In-hospital mortality was lower in pregnant versus nonpregnant HS patients: adjusted odds ratios (95% CI) for subarachnoid hemorrhage 0.17 (0.06-0.45) and intracerebral hemorrhage 0.57 (0.34-0.94). Pregnant subarachnoid hemorrhage patients also had a higher likelihood of home discharge (2.60 [1.67-4.06]) and independent ambulation at discharge (2.40 [1.56-3.70]). Pregnant HS patients are younger and have fewer risk factors than their nonpregnant counterparts, and risk-adjusted in-hospital mortality is lower. Our findings suggest possible differences in underlying disease pathophysiology and challenges to identifying at-risk patients. © 2015 American Heart Association, Inc.

Mexican Americans receive less intensive stroke rehabilitation than non Hispanic whites

PubMed Central

Morgenstern, Lewis B.; Sais, Emma; Fuentes, Michael; Ifejika, Nneka L.; Jiang, Xiaqing; Horn, Susan D.; Case, Erin; Lisabeth, Lynda D.

2017-01-01

Background and Purpose Mexican Americans (MAs) have worse neurologic, functional and cognitive outcomes after stroke. Stroke rehabilitation is important for good outcome. In a population-based study, we sought to determine if allocation of stroke rehabilitation services differed by ethnicity. Methods Stroke patients were identified as part of the Brain Attack Surveillance in Corpus Christi (BASIC) project, Texas, USA. Cases were validated by physicians using source documentation. Patients were followed prospectively for three months following stroke to determine rehabilitation services and transitions. Descriptive statistics were used to depict the study population. Continuous baseline variables were compared using two sample t-tests or Wilcoxon rank-sum tests by ethnicity. Categorical baseline variables were compared using chi-squared tests. Ethnic comparisons of rehabilitation services were compared using chi-squared tests, Fisher’s exact tests and logistic regression. Results Seventy-two subjects (50 MA and 22 non-Hispanic white [NHW]) were followed. Mean age, NHW-69 (sd-13), MA-66 (sd-11) years, sex (NHW 55% male, MA 50% male) and median presenting NIHSS did not differ significantly. There were no ethnic differences among the proportion of patients who were sent home without any rehabilitation services (p=0.9). Among those who received rehabilitation NHWs were more likely to get inpatient rehabilitation (73%) compared with MAs (30%), p=0.016. MAs (51%) were much more likely to receive home rehabilitation services compared with NHWs (0%) (p=0.0017). Conclusions In this population-based study, MAs were more likely to receive home-based rehabilitation while NHWs more likely to get inpatient rehabilitation. This disparity may, in part, explain the worse stroke outcome in MAs. PMID:28386042

A Bayesian Theory of Sequential Causal Learning and Abstract Transfer.

PubMed

Lu, Hongjing; Rojas, Randall R; Beckers, Tom; Yuille, Alan L

2016-03-01

Two key research issues in the field of causal learning are how people acquire causal knowledge when observing data that are presented sequentially, and the level of abstraction at which learning takes place. Does sequential causal learning solely involve the acquisition of specific cause-effect links, or do learners also acquire knowledge about abstract causal constraints? Recent empirical studies have revealed that experience with one set of causal cues can dramatically alter subsequent learning and performance with entirely different cues, suggesting that learning involves abstract transfer, and such transfer effects involve sequential presentation of distinct sets of causal cues. It has been demonstrated that pre-training (or even post-training) can modulate classic causal learning phenomena such as forward and backward blocking. To account for these effects, we propose a Bayesian theory of sequential causal learning. The theory assumes that humans are able to consider and use several alternative causal generative models, each instantiating a different causal integration rule. Model selection is used to decide which integration rule to use in a given learning environment in order to infer causal knowledge from sequential data. Detailed computer simulations demonstrate that humans rely on the abstract characteristics of outcome variables (e.g., binary vs. continuous) to select a causal integration rule, which in turn alters causal learning in a variety of blocking and overshadowing paradigms. When the nature of the outcome variable is ambiguous, humans select the model that yields the best fit with the recent environment, and then apply it to subsequent learning tasks. Based on sequential patterns of cue-outcome co-occurrence, the theory can account for a range of phenomena in sequential causal learning, including various blocking effects, primacy effects in some experimental conditions, and apparently abstract transfer of causal knowledge. Copyright © 2015 Cognitive Science Society, Inc.

Efficacy of a novel strategy for poststernotomy deep sternal infection after thoracic aorta replacement using a prosthetic graft.

PubMed

Kuriyama, Motone; Yoshida, Yukitaka; Ninomiya, Hitoshi; Yamamoto, Shin; Sasaguri, Shiro; Akita, Shinsuke; Mitsukawa, Nobuyuki

2018-05-01

Poststernotomy deep sternal wound infections are persistent and occasionally fatal, especially in cases involving prosthetic grafts, because of their complicated structure and virtual impossibility of removal. We aimed to verify the influence of cooperation with plastic surgeons and our novel strategy for treating deep sternal wound infection after aortic replacement on cardiovascular surgery outcomes. Nine hundred eighty-three consecutive patients were divided into two groups: an early group (2012-2013) and a late group (2014-2015). The late group had received cooperatively improved perioperative wound management: our novel strategy of deep sternal infection based on radical debridement and immediate reconstruction decided by reference to severities of the patient's general condition and widespread infection by early intervention of plastic surgeons. The groups were analysed retrospectively. Binary variables were analysed statistically with the Fisher exact test and continuous variables with the Mann-Whitney U test. Inter-group differences were assessed with the chi-square test. Twenty of 390 cases in the early group and 13 of 593 cases in the late group were associated with deep sternal infection. Morbidity rates of deep sternal wound infection and associated mortality rates 1 year after reconstruction surgery were significantly less (p <0.05 for both) in the late group. Intervention by plastic surgeons improved perioperative wound management outcomes. Our treatment strategy for deep sternal wound infection also reduced associated mortality rates. Facilities should consider the early inclusion of plastic surgeons in the treatment of patients undergoing aortic replacement to facilitate better outcomes. Copyright © 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

A Bayesian Semiparametric Latent Variable Model for Mixed Responses

ERIC Educational Resources Information Center

Fahrmeir, Ludwig; Raach, Alexander

2007-01-01

In this paper we introduce a latent variable model (LVM) for mixed ordinal and continuous responses, where covariate effects on the continuous latent variables are modelled through a flexible semiparametric Gaussian regression model. We extend existing LVMs with the usual linear covariate effects by including nonparametric components for nonlinear…

Thyroid Function Variations Within the Reference Range Do Not Affect Quality of Life, Mood, or Cognitive Function in Community-Dwelling Older Men.

PubMed

Samuels, Mary H; Kaimal, Rajani; Waring, Avantika; Fink, Howard A; Yaffe, Kristine; Hoffman, Andrew R; Orwoll, Eric; Bauer, Douglas

2016-09-01

Variations in thyroid function within the laboratory reference range have been associated with a number of clinical outcomes. However, quality of life, mood, and cognitive function have not been extensively studied, and it is not clear whether mild variations in thyroid function have major effects on these neurocognitive outcomes. Data were analyzed from the Osteoporotic Fractures in Men (MrOS) Study, a cohort of community-dwelling men aged 65 years and older in the United States. A total of 539 participants who were not taking thyroid medications and had age-adjusted TSH levels within the reference range underwent detailed testing of quality of life, mood, and cognitive function at baseline. The same quality of life, mood, and cognitive outcomes were measured again in 193 of the men after a mean follow-up of 6 years. Outcomes were analyzed using thyrotropin (TSH) and free thyroxine (FT4) levels as continuous independent variables, adjusting for relevant covariates. At baseline, there were no associations between TSH or FT4 levels and measures of quality of life, mood, or cognition in the 539 euthyroid men. Baseline thyroid function did not predict changes in these outcomes over a mean of 6 years in the 193 men in the longitudinal analysis. Variations in thyroid function within the age-adjusted laboratory reference range are not associated with variations in quality of life, mood, or cognitive function in community-dwelling older men.

Within-Subject Mediation Analysis in AB/BA Crossover Designs.

PubMed

Josephy, Haeike; Vansteelandt, Stijn; Vanderhasselt, Marie-Anne; Loeys, Tom

2015-05-01

Crossover trials are widely used to assess the effect of a reversible exposure on an outcome of interest. To gain further insight into the underlying mechanisms of this effect, researchers may be interested in exploring whether or not it runs through a specific intermediate variable: the mediator. Mediation analysis in crossover designs has received scant attention so far and is mostly confined to the traditional Baron and Kenny approach. We aim to tackle mediation analysis within the counterfactual framework and elucidate the assumptions under which the direct and indirect effects can be identified in AB/BA crossover studies. Notably, we show that both effects are identifiable in certain statistical models, even in the presence of unmeasured time-independent (or upper-level) confounding of the mediator-outcome relation. Employing the mediation formula, we derive expressions for the direct and indirect effects in within-subject designs for continuous outcomes that lend themselves to linear modelling, under a large variety of settings. We discuss an estimation approach based on regressing differences in outcomes on differences in mediators and show how to allow for period effects as well as different types of moderation. The performance of this approach is compared to other existing methods through simulations and is illustrated with data from a neurobehavioural study. Lastly, we demonstrate how a sensitivity analysis can be performed that is able to assess the robustness of both the direct and indirect effect against violation of the "no unmeasured lower-level mediator-outcome confounding" assumption.

Psychological contract breach and outcomes: Combining meta-analysis and structural equation models.

PubMed

Topa Cantisano, Gabriela; Morales Domínguez, J Francisco; Depolo, Marco

2008-08-01

In this study, meta-analytic procedures were used to examine the relationships between psychological contract perceived breach and certain outcome variables, such as organizational commitment, job satisfaction and organizational citizenship behaviours (OCB). Our review of the literature generated 41 independent samples in which perceived breach was used as a predictor of these personal and organizational outcomes. A medium effect size (ES) for desirable outcomes (job satisfaction, organizational commitment, organizational trust, OCB and performance) was obtained (r=-.35). For undesirable outcomes (neglect in role duties and intention to leave), ES were also medium (r=.31). When comparing attitudinal (job satisfaction, organizational commitment, organizational trust) and behavioural outcomes (OCB, neglect in role duties and performance), a stronger ES was found for attitudinal (r=-.24) than for behavioural outcomes (r=-.11). Potential moderator variables were examined, and it was found that they explained only a percentage of variability of primary studies. Structural equation analysis of the pooled meta-analytical correlation matrix indicated that the relationships of perceived breach with satisfaction, OCB, intention to leave and performance are fully mediated by organizational trust and commitment. Results are discussed in order to suggest theoretical and empirical implications.

Improving health care, Part 1: The clinical value compass.

PubMed

Nelson, E C; Mohr, J J; Batalden, P B; Plume, S K

1996-04-01

CLINICAL VALUE COMPASS APPROACH: The clinical Value Compass, named to reflect its similarity in layout to a directional compass, has at its four cardinal points (1) functional status, risk status, and well-being; (2) costs; (3) satisfaction with health care and perceived benefit; and (4) clinical outcomes. To manage and improve the value of health care services, providers will need to measure the value of care for similar patient populations, analyze the internal delivery processes, run tests of changed delivery processes, and determine if these changes lead to better outcomes and lower costs. GETTING STARTED--OUTCOMES AND AIM: In the case example, the team's aim is "to find ways to continually improve the quality and value of care for AMI (acute myocardial infection) patients." VALUE MEASURES--SELECT A SET OF OUTCOME AND COST MEASURES: Four to 12 outcome and cost measures are sufficient to get started. In the case example, the team chose 1 or more measures for each quadrant of the value compass. An operational definition is a clearly specified method explaining how to measure a variable. Measures in the case example were based on information from the medical record, administrative and financial records, and patient reports and ratings at eight weeks postdischarge. Measurement systems that quantify the quality of processes and results of care are often add-ons to routine care delivery. However, the process of measurement should be intertwined with the process of care delivery so that front-line providers are involved in both managing the patient and measuring the process and related outcomes and costs.

An assessment of HIV treatment outcomes among utilizers of semi-mobile clinics in rural Kenya.

PubMed

Gorman, Sara E; Martinez, Jose M; Olson, Jennifer

2015-01-01

HIV/AIDS is a major cause of morbidity and mortality in Africa, and rates of retention in treatment are low. Some research has shown that mobile clinics are effective in connecting people in rural areas with health care. We compared HIV outcomes between HIV-positive patients who chose to access treatment from a regional hospital to those who chose care in one of four semi-mobile clinics closer to where they live. The subjects for this analysis were HIV-positive residents in West Pokot accessing care at one of four semi-mobile sites (Kabichbich, Chepareria, Kacheliba, and Sigor) or at the regional hospital in Kapenguria. We examined four outcome variables between the two groups: (1) retention in HIV treatment, (2) change in CD4 count, (3) adherence to ARVs, and (4) deaths. The patients who chose semi-mobile clinic care were less well educated, poorer, and sicker than those who chose to continue care in the regional hospital. There were no statistically significant differences between the groups in any of the four outcome measures. Although the population of patients attending semi-mobile clinics was on average poorer and sicker than those attending the hospital, their outcomes were similar. Care at the semi-mobile clinics did not result in significantly different outcomes from care in the district hospital. This program showed that semi-mobile clinics are a viable alternative to hospital care for very ill, isolated populations, but further measures must be taken to improve retention and adherence in these settings.

Advances in Statistical Methods for Substance Abuse Prevention Research

PubMed Central

MacKinnon, David P.; Lockwood, Chondra M.

2010-01-01

The paper describes advances in statistical methods for prevention research with a particular focus on substance abuse prevention. Standard analysis methods are extended to the typical research designs and characteristics of the data collected in prevention research. Prevention research often includes longitudinal measurement, clustering of data in units such as schools or clinics, missing data, and categorical as well as continuous outcome variables. Statistical methods to handle these features of prevention data are outlined. Developments in mediation, moderation, and implementation analysis allow for the extraction of more detailed information from a prevention study. Advancements in the interpretation of prevention research results include more widespread calculation of effect size and statistical power, the use of confidence intervals as well as hypothesis testing, detailed causal analysis of research findings, and meta-analysis. The increased availability of statistical software has contributed greatly to the use of new methods in prevention research. It is likely that the Internet will continue to stimulate the development and application of new methods. PMID:12940467

Assessing the Impact of Socioeconomic Variables on Small Area Variations in Suicide Outcomes in England

PubMed Central

Congdon, Peter

2012-01-01

Ecological studies of suicide and self-harm have established the importance of area variables (e.g., deprivation, social fragmentation) in explaining variations in suicide risk. However, there are likely to be unobserved influences on risk, typically spatially clustered, which can be modeled as random effects. Regression impacts may be biased if no account is taken of spatially structured influences on risk. Furthermore a default assumption of linear effects of area variables may also misstate or understate their impact. This paper considers variations in suicide outcomes for small areas across England, and investigates the impact on them of area socio-economic variables, while also investigating potential nonlinearity in their impact and allowing for spatially clustered unobserved factors. The outcomes are self-harm hospitalisations and suicide mortality over 6,781 Middle Level Super Output Areas. PMID:23271304

Assessing the impact of socioeconomic variables on small area variations in suicide outcomes in England.

PubMed

Congdon, Peter

2012-12-27

Ecological studies of suicide and self-harm have established the importance of area variables (e.g., deprivation, social fragmentation) in explaining variations in suicide risk. However, there are likely to be unobserved influences on risk, typically spatially clustered, which can be modeled as random effects. Regression impacts may be biased if no account is taken of spatially structured influences on risk. Furthermore a default assumption of linear effects of area variables may also misstate or understate their impact. This paper considers variations in suicide outcomes for small areas across England, and investigates the impact on them of area socio-economic variables, while also investigating potential nonlinearity in their impact and allowing for spatially clustered unobserved factors. The outcomes are self-harm hospitalisations and suicide mortality over 6,781 Middle Level Super Output Areas.

Generic versus disorder specific cognitive behavior therapy for social anxiety disorder in youth: A randomized controlled trial using internet delivery.

PubMed

Spence, Susan H; Donovan, Caroline L; March, Sonja; Kenardy, Justin A; Hearn, Cate S

2017-03-01

The study examined whether the efficacy of cognitive behavioral treatment for Social Anxiety Disorder for children and adolescents is increased if intervention addresses specific cognitive and behavioral factors linked to the development and maintenance of SAD in young people, over and above the traditional generic CBT approach. Participants were 125 youth, aged 8-17 years, with a primary diagnosis of SAD, who were randomly assigned to generic CBT (CBT-GEN), social anxiety specific CBT (CBT-SAD) or a wait list control (WLC). Intervention was delivered using a therapist-supported online program. After 12-weeks, participants who received treatment (CBT-SAD or CBT-GEN) showed significantly greater reduction in social anxiety and post-event processing, and greater improvement in global functioning than the WLC but there was no significant difference between CBT-SAD and CBT-GEN on any outcome variable at 12-weeks or 6-month follow-up. Despite significant reductions in anxiety, the majority in both treatment conditions continued to meet diagnostic criteria for SAD at 6-month follow-up. Decreases in social anxiety were associated with decreases in post-event processing. Future research should continue to investigate disorder-specific interventions for SAD in young people, drawing on evidence regarding causal or maintaining factors, in order to enhance treatment outcomes for this debilitating condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effectiveness of two rehabilitation strategies provided by nurses for stroke patients in Mexico.

PubMed

Torres-Arreola, Laura del Pilar; Doubova Dubova, Svetlana Vladislavovna; Hernandez, Sergio F; Torres-Valdez, Laura E; Constantino-Casas, Norma P; Garcia-Contreras, Fernando; Torres-Castro, Sara

2009-11-01

Rehabilitation strategies have been developed to improve functional state in stroke patients. The main objective of this study was to evaluate the effectiveness of the early rehabilitation at hospital and its continuity at home provided by nurses, on the functional recovery of basic and social activities in stroke patients compared with conventional care. A randomised clinical trial was carried out in three general hospitals of the Mexican Institute of Social Security (IMSS) in Mexico City between April 2003-May 2004. Stroke patients. Two rehabilitation strategies provided by nurses for stroke patients were compared: physiotherapy plus caregiver education in rehabilitation (strategy 1, S1) vs. education alone (strategy 2, S2). The main outcome variables were the basic (Barthel index) and social (Frenchay activities index) activities of daily living, of each patient. Age, sex, morbidity, stroke symptoms, complications, neurological damage (Canadian Scale), cognitive state (mini-mental state examination questionnaire) and duration of hospitalisation were defined as the control variables. Patients were evaluated at baseline and months one, three and six thereafter. One hundred and ten patients with ischaemic stroke were enrolled and randomised; 59 were assigned to S1 and 51 to S2. Comparison of the outcome variables showed that patients improved significantly over time, but no differences were observed between groups. We observed no significant difference in strategy performance with regard to the basic and instrumental activities of daily living. Participants who received physiotherapy with additional caregiver education benefit no more than those whose caregivers received education alone. Those countries that do not have integral rehabilitation programmes for stroke patients should understand their importance and budget resources for them. Meanwhile, both caregiver education and nurses trained in specific care and physiotherapy are alternatives that benefit these patients.

Risk modeling for ventricular assist device support in post-cardiotomy shock.

PubMed

Alsoufi, Bahaaldin; Rao, Vivek; Tang, Augustine; Maganti, Manjula; Cusimano, Robert

2012-04-01

Post-cardiotomy shock (PCS) has a complex etiology. Although treatment with inotrops and intra-aortic balloon pump (IABP) support improves cardiac performance, end-organ injuries are common and lead to prolonged ICU stay, extended hospitalization and increased mortality. Early consideration of mechanical circulatory support may prevent such complications and improve outcome. Between January 1997 and January 2002, 321 patients required IABP and inotropic support for PCS following coronary artery bypass grafting (CABG) at our institution. Perioperative variables including age, mixed venous saturation (MVO2), inotropic requirements and LV function were analyzed using multivariate statistical methods. All explanatory variables with a univariate p value <0.10 were entered into a stepwise logistic regression model to predict hospital mortality. Odds ratios from significant variables (p < 0.05) in the regression model were used to compose a risk score. Overall hospital mortality was 16%. The independent risk factors for mortality in this population were: MVO2 < 60% (OR = 3.2), milrinone > 0.5 μg/kg/min (OR = 3.2), age > 75 (OR = 2.7), adrenaline > 0.1 μg/kg/min (OR = 1.5). A 15-point risk score was developed based on the regression model. Hospital mortality in patients with a score >6 was 46% (n = 13/28), 3-6 was 31% (n = 9/29) and <3 was 11% (n = 29/264). A significant proportion of patients with PCS continue to face high mortality despite IABP and inotropic support. Advanced age, heavy inotropic dependency and poor oxygen delivery all predicted increased risk for death. Further investigation is needed to assess whether early institution of VAD support could improve outcome in this high-risk group of patients.

Comparative study of the Aristotle Comprehensive Complexity and the Risk Adjustment in Congenital Heart Surgery scores.

PubMed

Bojan, Mirela; Gerelli, Sébastien; Gioanni, Simone; Pouard, Philippe; Vouhé, Pascal

2011-09-01

The Aristotle Comprehensive Complexity (ACC) and the Risk Adjustment in Congenital Heart Surgery (RACHS-1) scores have been proposed for complexity adjustment in the analysis of outcome after congenital heart surgery. Previous studies found RACHS-1 to be a better predictor of outcome than the Aristotle Basic Complexity score. We compared the ability to predict operative mortality and morbidity between ACC, the latest update of the Aristotle method and RACHS-1. Morbidity was assessed by length of intensive care unit stay. We retrospectively enrolled patients undergoing congenital heart surgery. We modeled each score as a continuous variable, mortality as a binary variable, and length of stay as a censored variable. We compared performance between mortality and morbidity models using likelihood ratio tests for nested models and paired concordance statistics. Among all 1,384 patients enrolled, 30-day mortality rate was 3.5% and median length of intensive care unit stay was 3 days. Both scores strongly related to mortality, but ACC made better prediction than RACHS-1; c-indexes 0.87 (0.84, 0.91) vs 0.75 (0.65, 0.82). Both scores related to overall length of stay only during the first postoperative week, but ACC made better predictions than RACHS-1; U statistic=0.22, p<0.001. No significant difference was noted after adjusting RACHS-1 models on age, prematurity, and major extracardiac abnormalities. The ACC was a better predictor of operative mortality and length of intensive care unit stay than RACHS-1. In order to achieve similar performance, regression models including RACHS-1 need to be further adjusted on age, prematurity, and major extracardiac abnormalities. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Posthospitalization home health care use and changes in functional status in a Medicare population.

PubMed

Hadley, J; Rabin, D; Epstein, A; Stein, S; Rimes, C

2000-05-01

The objective of this work was to estimate the effect of Medicare beneficiaries' use of home health care (HHC) for 6 months after hospital discharge on the change in functional status over a 1-year period beginning before hospitalization. Data came from the Medicare Current Beneficiary Survey, which is a nationally representative sample of Medicare beneficiaries, in-person interview data, and Medicare claims for 1991 through 1994 for 2,127 nondisabled, community-dwelling, elderly Medicare beneficiaries who were hospitalized within 6 months of their annual in-person interviews. Econometric estimation with the instrumental variable method was used to correct for observational data bias, ie, the nonrandom allocation of discharged beneficiaries to the use of posthospitalization HHC. The analysis estimates a first-stage model of HHC use from which an instrumental variable estimate is constructed to estimate the effect on change in functional status. The instrumental variable estimates suggest that HHC users experienced greater improvements in functional status than nonusers as measured by the change in a continuous scale based on the number and mix of activities of daily living and instrumental activities of daily living before and after hospitalization. The estimated improvement in functional status could be as large as 13% for a 10% increase in HHC use. In contrast, estimation with the observational data on HHC use implies that HHC users had poorer health outcomes. Adjusting for potential observational data bias is critical to obtaining estimates of the relationship between the use of posthospitalization HHC and the change in health before and after hospitalization. After adjustment, the results suggest that efforts to constrain Medicare's spending for HHC, as required by the Balanced Budget Act of 1997, may lead to poorer health outcomes for some beneficiaries.

Effects of Person-Centered Physical Therapy on Fatigue-Related Variables in Persons With Rheumatoid Arthritis: A Randomized Controlled Trial.

PubMed

Feldthusen, Caroline; Dean, Elizabeth; Forsblad-d'Elia, Helena; Mannerkorpi, Kaisa

2016-01-01

To examine effects of person-centered physical therapy on fatigue and related variables in persons with rheumatoid arthritis (RA). Randomized controlled trial. Hospital outpatient rheumatology clinic. Persons with RA aged 20 to 65 years (N=70): intervention group (n=36) and reference group (n=34). The 12-week intervention, with 6-month follow-up, focused on partnership between participant and physical therapist and tailored health-enhancing physical activity and balancing life activities. The reference group continued with regular activities; both groups received usual health care. Primary outcome was general fatigue (visual analog scale). Secondary outcomes included multidimensional fatigue (Bristol Rheumatoid Arthritis Fatigue Multi-Dimensional Questionnaire) and fatigue-related variables (ie, disease, health, function). At posttest, general fatigue improved more in the intervention group than the reference group (P=.042). Improvement in median general fatigue reached minimal clinically important differences between and within groups at posttest and follow-up. Improvement was also observed for anxiety (P=.0099), and trends toward improvements were observed for most multidimensional aspects of fatigue (P=.023-.048), leg strength/endurance (P=.024), and physical activity (P=.023). Compared with the reference group at follow-up, the intervention group improvement was observed for leg strength/endurance (P=.001), and the trends toward improvements persisted for physical (P=.041) and living-related (P=.031) aspects of fatigue, physical activity (P=.019), anxiety (P=.015), self-rated health (P=.010), and self-efficacy (P=.046). Person-centered physical therapy focused on health-enhancing physical activity and balancing life activities showed significant benefits on fatigue in persons with RA. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Bias, Confounding, and Interaction: Lions and Tigers, and Bears, Oh My!

PubMed

Vetter, Thomas R; Mascha, Edward J

2017-09-01

Epidemiologists seek to make a valid inference about the causal effect between an exposure and a disease in a specific population, using representative sample data from a specific population. Clinical researchers likewise seek to make a valid inference about the association between an intervention and outcome(s) in a specific population, based upon their randomly collected, representative sample data. Both do so by using the available data about the sample variable to make a valid estimate about its corresponding or underlying, but unknown population parameter. Random error in an experiment can be due to the natural, periodic fluctuation or variation in the accuracy or precision of virtually any data sampling technique or health measurement tool or scale. In a clinical research study, random error can be due to not only innate human variability but also purely chance. Systematic error in an experiment arises from an innate flaw in the data sampling technique or measurement instrument. In the clinical research setting, systematic error is more commonly referred to as systematic bias. The most commonly encountered types of bias in anesthesia, perioperative, critical care, and pain medicine research include recall bias, observational bias (Hawthorne effect), attrition bias, misclassification or informational bias, and selection bias. A confounding variable is a factor associated with both the exposure of interest and the outcome of interest. A confounding variable (confounding factor or confounder) is a variable that correlates (positively or negatively) with both the exposure and outcome. Confounding is typically not an issue in a randomized trial because the randomized groups are sufficiently balanced on all potential confounding variables, both observed and nonobserved. However, confounding can be a major problem with any observational (nonrandomized) study. Ignoring confounding in an observational study will often result in a "distorted" or incorrect estimate of the association or treatment effect. Interaction among variables, also known as effect modification, exists when the effect of 1 explanatory variable on the outcome depends on the particular level or value of another explanatory variable. Bias and confounding are common potential explanations for statistically significant associations between exposure and outcome when the true relationship is noncausal. Understanding interactions is vital to proper interpretation of treatment effects. These complex concepts should be consistently and appropriately considered whenever one is not only designing but also analyzing and interpreting data from a randomized trial or observational study.

Integrating Ecosystem Carbon Dynamics into State-and-Transition Simulation Models of Land Use/Land Cover Change

NASA Astrophysics Data System (ADS)

Sleeter, B. M.; Daniel, C.; Frid, L.; Fortin, M. J.

2016-12-01

State-and-transition simulation models (STSMs) provide a general approach for incorporating uncertainty into forecasts of landscape change. Using a Monte Carlo approach, STSMs generate spatially-explicit projections of the state of a landscape based upon probabilistic transitions defined between states. While STSMs are based on the basic principles of Markov chains, they have additional properties that make them applicable to a wide range of questions and types of landscapes. A current limitation of STSMs is that they are only able to track the fate of discrete state variables, such as land use/land cover (LULC) classes. There are some landscape modelling questions, however, for which continuous state variables - for example carbon biomass - are also required. Here we present a new approach for integrating continuous state variables into spatially-explicit STSMs. Specifically we allow any number of continuous state variables to be defined for each spatial cell in our simulations; the value of each continuous variable is then simulated forward in discrete time as a stochastic process based upon defined rates of change between variables. These rates can be defined as a function of the realized states and transitions of each cell in the STSM, thus providing a connection between the continuous variables and the dynamics of the landscape. We demonstrate this new approach by (1) developing a simple IPCC Tier 3 compliant model of ecosystem carbon biomass, where the continuous state variables are defined as terrestrial carbon biomass pools and the rates of change as carbon fluxes between pools, and (2) integrating this carbon model with an existing LULC change model for the state of Hawaii, USA.

A comparison of robotic single-incision and traditional single-incision laparoscopic cholecystectomy.

PubMed

Gustafson, Monica; Lescouflair, Tariq; Kimball, Randall; Daoud, Ibrahim

2016-06-01

Surgeons continually strive to improve technology and patient care. One remarkable demonstration of this is the development of laparoscopic surgery. Once this proved to be a safe and reliable surgical approach, robotics seemed a logical progression of surgical technology. The aim of this project was to evaluate the utility of robotics in the context of single-incision laparoscopic cholecystectomy (SILC). A retrospective review of a prospectively maintained database of robotic single-incision laparoscopic cholecystectomy (RSILC) and traditional SILC performed by a single surgeon at our institution from July 2010 to August 2013 was queried. All consecutive patients undergoing RSILC and SILC during this time period were included. Primary outcomes include conversion rate and operative time. Secondary outcomes include length of stay, duration of narcotic use, time to independent performance of daily activities and cost. Categorical variables were evaluated using Chi-square analysis and continuous variables using t test or Wilcoxon's rank test. Thirty-eight patients underwent RSILC and 44 underwent SILC. BMI was higher in the RSILC group, and the number of patients with prior abdominal surgeries was higher in the SILC group. Otherwise, demographics were similar between the two groups. There was no difference in conversion rate between RSILC and SILC (8 vs 11 %, p = 0.60). Mean operative time for RSILC was significantly greater compared with SILC (98 vs 68 min, p < 0.0001). RSILC was associated with a longer duration of narcotic use (2.3 vs 1.7 days, p = 0.0019) and time to independent performance of daily activities (4 vs 2.3 days, p < 0.0001). Total cost is greater in RSILC ($8961 vs $5379, p < 0.0001). While RSILC can be safely performed, it is associated with longer operative times and greater cost.

Mortality after surgery in Europe: a 7 day cohort study.

PubMed

Pearse, Rupert M; Moreno, Rui P; Bauer, Peter; Pelosi, Paolo; Metnitz, Philipp; Spies, Claudia; Vallet, Benoit; Vincent, Jean-Louis; Hoeft, Andreas; Rhodes, Andrew

2012-09-22

Clinical outcomes after major surgery are poorly described at the national level. Evidence of heterogeneity between hospitals and health-care systems suggests potential to improve care for patients but this potential remains unconfirmed. The European Surgical Outcomes Study was an international study designed to assess outcomes after non-cardiac surgery in Europe. We did this 7 day cohort study between April 4 and April 11, 2011. We collected data describing consecutive patients aged 16 years and older undergoing inpatient non-cardiac surgery in 498 hospitals across 28 European nations. Patients were followed up for a maximum of 60 days. The primary endpoint was in-hospital mortality. Secondary outcome measures were duration of hospital stay and admission to critical care. We used χ(2) and Fisher's exact tests to compare categorical variables and the t test or the Mann-Whitney U test to compare continuous variables. Significance was set at p<0·05. We constructed multilevel logistic regression models to adjust for the differences in mortality rates between countries. We included 46,539 patients, of whom 1855 (4%) died before hospital discharge. 3599 (8%) patients were admitted to critical care after surgery with a median length of stay of 1·2 days (IQR 0·9-3·6). 1358 (73%) patients who died were not admitted to critical care at any stage after surgery. Crude mortality rates varied widely between countries (from 1·2% [95% CI 0·0-3·0] for Iceland to 21·5% [16·9-26·2] for Latvia). After adjustment for confounding variables, important differences remained between countries when compared with the UK, the country with the largest dataset (OR range from 0·44 [95% CI 0·19-1·05; p=0·06] for Finland to 6·92 [2·37-20·27; p=0·0004] for Poland). The mortality rate for patients undergoing inpatient non-cardiac surgery was higher than anticipated. Variations in mortality between countries suggest the need for national and international strategies to improve care for this group of patients. European Society of Intensive Care Medicine, European Society of Anaesthesiology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Masculine role adherence and outcomes among men with traumatic brain injury.

PubMed

Schopp, Laura H; Good, Glenn E; Barker, Katharine B; Mazurek, Micah O; Hathaway, Stefani L

2006-10-01

Traumatic brain injury (TBI) is a significant health problem disproportionately affecting men and is often associated with changes in masculine role functioning in life domains such as vocational functioning, sexual and inter-personal functioning and personal independence. These changes could have serious implications for men's adjustment following injury. The aim of this study was to examine the relations among traditional masculine role adherence, psychosocial adjustment and rehabilitation outcomes in men with TBI. A correlational design was chosen to examine the relations among variables. Spearman correlations and Wilcoxon Rank Sum tests were used to examine relationships between masculine role variables and outcome variables. The study included 33 men with TBI who had been discharged from inpatient rehabilitation within 5 years. Participants completed surveys on traditional masculine gender role adherence and gender role conflict and additional data, including measures of functional outcome, life satisfaction, psychosocial outcomes and earnings, were obtained through the TBI Model System longitudinal data collection system. The results revealed significant associations between masculine role adherence and satisfaction with life, follow-up earnings and FIM change from admission to discharge. In the current study, particular masculine role variables corresponded to different functional and psychological outcomes. Understanding these differences provides new directions for treatment and offers important information about aspects of traditional masculine roles that may enhance or hinder adjustment to injury.

The relationship between happiness and intelligent quotient: the contribution of socio-economic and clinical factors.

PubMed

Ali, A; Ambler, G; Strydom, A; Rai, D; Cooper, C; McManus, S; Weich, S; Meltzer, H; Dein, S; Hassiotis, A

2013-06-01

Happiness and higher intelligent quotient (IQ) are independently related to positive health outcomes. However, there are inconsistent reports about the relationship between IQ and happiness. The aim was to examine the association between IQ and happiness and whether it is mediated by social and clinical factors. Method The authors analysed data from the 2007 Adult Psychiatric Morbidity Survey in England. The participants were adults aged 16 years or over, living in private households in 2007. Data from 6870 participants were included in the study. Happiness was measured using a validated question on a three-point scale. Verbal IQ was estimated using the National Adult Reading Test and both categorical and continuous IQ was analysed. Happiness is significantly associated with IQ. Those in the lowest IQ range (70-99) reported the lowest levels of happiness compared with the highest IQ group (120-129). Mediation analysis using the continuous IQ variable found dependency in activities of daily living, income, health and neurotic symptoms were strong mediators of the relationship, as they reduced the association between happiness and IQ by 50%. Those with lower IQ are less happy than those with higher IQ. Interventions that target modifiable variables such as income (e.g. through enhancing education and employment opportunities) and neurotic symptoms (e.g. through better detection of mental health problems) may improve levels of happiness in the lower IQ groups.

Shared medical appointments for patients with diabetes mellitus: a systematic review.

PubMed

Edelman, David; Gierisch, Jennifer M; McDuffie, Jennifer R; Oddone, Eugene; Williams, John W

2015-01-01

Shared medical appointments (SMAs) are an increasingly used system-redesign strategy for improving access to and quality of chronic illness care. We conducted a systematic review of the existing literature on SMA interventions for patients with diabetes in order to understand their impact on outcomes. MEDLINE, EMBASE, CINAHL, PsycINFO, and Web of Science from January 1996 through April 2012. PubMed search updated June 2013. English-language peer-reviewed publications of randomized controlled trials (RCTs), nonrandomized cluster controlled trials, controlled before-and-after studies, or interrupted time-series designs conducted among adult patients with diabetes. Two independent reviewers used prespecified criteria to screen titles and abstracts for full text review. Two different reviewers abstracted data and rated study quality and strength of evidence. When possible, we used random-effects models to synthesize the effects quantitatively, reporting by a weighted difference of the means when the same scale was used across studies, and a standardized mean difference when the scales differed. We measured heterogeneity in study effects using Forest Plots, Cochran's Q, and I(2), and explored heterogeneity by using subgroup analyses for categorical variables and meta-regression analyses for continuous or discrete variables. Outcomes not suitable to meta-analysis were summarized qualitatively. Twenty-five articles representing 17 unique studies compared SMA interventions with usual care. Among patients with diabetes, SMAs improved hemoglobin A1c (∆ = -0.55 percentage points [95 % CI, -0.11 to -0.99]); improved systolic blood pressure (∆ = -5.2 mmHg [95 % CI, -3.0 to -7.4]); and did not improve LDL cholesterol (∆ = -6.6 mg/dl [95 % CI, 2.8 to -16.1]). Nonbiophysical outcomes, including economic outcomes, were reported too infrequently to meta-analyze, or to draw conclusions from. The A1c result had significant heterogeneity among studies, likely secondary to the heterogeneity among included SMA interventions. Heterogeneity among the components of diabetes SMAs leads to uncertainty about what makes a particular SMA successful. SMA interventions improve biophysical outcomes among patients with diabetes. There was inadequate literature to determine SMA effects on patient experience, utilization, and costs.

Dissociable Effects of Cocaine Dependence on Reward Processes: The Role of Acute Cocaine and Craving.

PubMed

Rose, Emma Jane; Salmeron, Betty Jo; Ross, Thomas J; Waltz, James; Schweitzer, Julie B; Stein, Elliot A

2017-02-01

The relative impact of chronic vs acute cocaine on dependence-related variability in reward processing in cocaine-dependent individuals (CD) is not well understood, despite the relevance of such effects to long-term outcomes. To dissociate these effects, CD (N=15) and healthy controls (HC; N=15) underwent MRI two times while performing a monetary incentive delay task. Both scans were identical across subjects/groups, except that, in a single-blind, counterbalanced design, CD received intravenous cocaine (30 mg/70 kg) before one session (CD+cocaine) and saline in another (CD+saline). Imaging analyses focused on activity related to anticipatory valence (gain/loss), anticipatory magnitude (small/medium/large), and reinforcing outcomes (successful/unsuccessful). Drug condition (cocaine vs saline) and group (HC vs CD+cocaine or CD+saline) did not influence valence-related activity. However, compared with HC, magnitude-related activity for gains was reduced in CD in the left cingulate gyrus post-cocaine and in the left putamen in the abstinence/saline condition. In contrast, magnitude-dependent activity for losses increased in CD vs HC in the right inferior parietal lobe post-cocaine and in the left superior frontal gyrus post-saline. Across outcomes (ie, successful and unsuccessful) activity in the right habenula decreased in CD in the abstinence/saline condition vs acute cocaine and HC. Cocaine-dependent variability in outcome- and loss-magnitude activity correlated negatively with ratings of cocaine craving and positively with how high subjects felt during the scanning session. Collectively, these data suggest dissociable effects of acute cocaine on non-drug reward processes, with cocaine consumption partially ameliorating dependence-related insensitivity to reinforcing outcomes/'liking', but having no discernible effect on dependence-related alterations in incentive salience/'wanting'. The relationship of drug-related affective sequelae to non-drug reward processing suggests that CD experience a general alteration of reward function and may be motivated to continue using cocaine for reasons beyond desired drug-related effects. This may have implications for individual differences in treatment efficacy for approaches that rely on reinforcement strategies (eg, contingency management) and for the long-term success of treatment.

Short- and long-term outcomes following pelvic exenteration for gynae-oncological and colorectal cancers: A 9 year consecutive single-centre cohort study.

PubMed

Katory, Mark; McLean, Ross; Paez, Edgar; Kucukmetin, Ali; Naik, Raj

2017-07-01

Radical pelvic exenteration can be undertaken for locally invasive or recurrent disease in both colorectal and gynaecological malignancies. In the UK this procedure is usually undertaken by the respective surgical specialties who have undergone divergent surgical training. This study describes and compares outcomes between colorectal and gynae-oncological teams following pelvic exenteration for primary and recurrent gynaecological and colorectal cancers in a single-centre multi-disciplinary team. A retrospective review of consecutive pelvic exenteration patients undertaken over a nine-year period in a tertiary referral centre. Analyses comparing short- and long-term morbidity and mortality outcomes were undertaken by chi-square test for categorical variables and Mann-Whitney U for continuous variables. Cumulative survival rates were calculated according to the Kaplan-Meier method and factors associated with recurrence and survival determined using a Cox regression model. Thirty-four exenterations were undertaken; fourteen colorectal and twenty gynae-oncological. Morbidity was seen in 50% of colorectal and 75% of gynae-oncological patients. Recurrence was seen earlier and with greater frequency in the gynaeoncology group (44.4% and median time 11 months) than the colorectal group (21.4%, median time 41 months; p > 0.05). Survival in the gynae-oncology group was also lower than the colorectal group at 1-year (69.6% vs. 92.9%) and 5-years (58.0% vs. 92.9%; p = 0.115). The majority of gynae-oncological mortality occurred within 3-years of surgery, whilst the majority of mortality in the colorectal group was after 5-years. Long-term patient outcome measures, including disease recurrence and 5-year survival, for colorectal exenteration appear better than for gynaeoncology patients, however, no statistical significant difference exists between short-term outcome measures between specialties. This is likely to be caused by different baseline pathologies and disease pattern influencing longer term prognosis but may also be a function of differing surgical thresholds and patient selection bias between specialties. Peri-operative and short-term morbidity appear equivalent despite divergent surgical backgrounds and training. Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

Community-Based Psychosocial Treatment Has an Impact on Social Processing and Functional Outcome in Schizophrenia.

PubMed

Varga, Eszter; Endre, Szilvia; Bugya, Titusz; Tényi, Tamás; Herold, Róbert

2018-01-01

Schizophrenic patients have serious impairments in social cognition, which often persists after significant reduction in clinical symptoms. Community-based psychosocial treatments aim to recover social functioning for mentally ill individuals. Our aim was to examine prospective changes in social cognition and functional outcomes in two groups of schizophrenic patients involved in two forms of community-based psychosocial treatments namely case management (CM) and community-based club (CC) compared to a matched, treatment as usual (TAU) group of patients. We hypothesized that CC and CM groups would exhibit better functional and social cognitive outcomes after a 6-month long psychosocial treatment period. Seventy-five patients participated either in CC, CM or TAU. Both CC and CM took part in community-based psychosocial treatment programs including trainings, such as communication and assertiveness trainings. In addition, CC provided group therapeutic treatments and a continuously available day care where patients had the possibility to participate in various social interactions. All participants were in remission, and on maintenance antipsychotic treatment. Participants were assessed on all study variables at two time points: baseline and after 6 months with a battery of questionnaires that examined affective face perception, affective prosody perception, pragmatic language comprehension and ToM. Our results showed that functional outcomes improved significantly in the CC as well as in the CM groups, in contrast to the TAU group. While analyzing summary scores of social cognition, it was found that only the CC group increased its performance in social cognition. In addition, a significant between-group difference in social cognitive function was found after 6 months between the three groups, with the CC group performing best. When investigating associations between changes in social cognition and changes in functional outcomes during a 6-month long treatment period, we found significant correlations between the two variables both in the CC and in the CM groups. Based on our results, we suggest that a rich interpersonal network and social support have highly beneficial effects on social cognition and we would like to emphasize the necessity of offering community-based psychosocial treatments beside antipsychotic medications as early as possible as a crucial part of the complex therapy of schizophrenia.

Patterned feeding experience for preterm infants: study protocol for a randomized controlled trial.

PubMed

Pickler, Rita H; Wetzel, Paul A; Meinzen-Derr, Jareen; Tubbs-Cooley, Heather L; Moore, Margo

2015-06-04

Neurobehavioral disabilities occur in 5-15% of preterm infants with an estimated 50-70% of very low birth weight preterm infants experiencing later dysfunction, including cognitive, behavioral, and social delays that often persist into adulthood. Factors implicated in poor neurobehavioral and developmental outcomes are hospitalization in the neonatal intensive care unit (NICU) and inconsistent caregiving patterns. Although much underlying brain damage occurs in utero or shortly after birth, neuroprotective strategies can stop lesions from progressing, particularly when these strategies are used during the most sensitive periods of neural plasticity occurring months before term age. The purpose of this randomized trial is to test the effect of a patterned feeding experience on preterm infants' neurobehavioral organization and development, cognitive function, and clinical outcomes. This trial uses an experimental, longitudinal, 2-group design with 120 preterm infants. Infants are enrolled within the first week of life and randomized to an experimental group receiving a patterned feeding experience from the first gavage feeding through discharge or to a control group receiving usual feeding care experience. The intervention involves a continuity of tactile experiences associated with feeding to train and build neuronal networks supportive of normal infant feeding experience. Primary outcomes are neurobehavioral organization as measured by Neurobehavioral Assessment of the Preterm Infant at 3 time points: the transition to oral feedings, NICU discharge, and 2 months corrected age. Secondary aims are cognitive function measured using the Bayley Scales of Infant and Toddler Development, Third Edition at 6 months corrected age, neurobehavioral development (sucking organization, feeding performance, and heart rate variability), and clinical outcomes (length of NICU stay and time to full oral feeding). The potential effects of demographic and biobehavioral factors (perinatal events and conditions of maternal or fetal/newborn origin and immunologic and genetic biomarkers) on the outcome variables will also be considered. Theoretically, the intervention provided at a critical time in neurologic system development and associated with a recurring event (feeding) should enhance neural connections that may be important for later development, particularly language and other cognitive and neurobehavioral organization skills. NCT01577615 11 April 2012.

Inguinal hernia repair: is there a benefit to using the robot?

PubMed

Charles, Eric J; Mehaffey, J Hunter; Tache-Leon, Carlos A; Hallowell, Peter T; Sawyer, Robert G; Yang, Zequan

2018-04-01

The number of robotic surgical procedures performed yearly is constantly rising, due to improved dexterity and visualization capabilities compared with conventional methods. We hypothesized that outcomes after robotic-assisted inguinal hernia repair would not be significantly different from outcomes after laparoscopic or open repair. All patients undergoing inguinal hernia repair between 2012 and 2016 were identified using institutional American College of Surgeons National Surgical Quality Improvement Program data. Demographics; preoperative, intraoperative, and postoperative characteristics; and outcomes were evaluated based on method of repair (Robot, Lap, or Open). Categorical variables were analyzed by Chi-square test and continuous variables using Mann-Whitney U. A total of 510 patients were identified who underwent unilateral inguinal hernia repair (Robot: 13.8% [n = 69], Lap: 48.1% [n = 241], Open: 38.1% [n = 191]). There were no demographic differences between groups other than age (Robot: 52 [39-62], Lap: 57 [45-67], and Open: 56 [48-67] years, p = 0.03). Operative duration was also different (Robot: 105 [76-146] vs. Lap: 81 [61-103] vs. Open: 71 [56-88] min, p < 0.001). There were no operative mortalities and all patients except one were discharged home the same day. Postoperative occurrences (adverse events, readmissions, and death) were similar between groups (Robot: 2.9% [2], Lap: 3.3% [8], Open: 5.2% [10], p = 0.53). Although rare, there was a significant difference in rate of postoperative skin and soft tissue infection (Robot: 2.9% [2] vs. Lap: 0% [0] vs. Open: 0.5% [1], p = 0.02). Cost was significantly different between groups (Robot: $7162 [$5942-8375] vs. Lap: $4527 [$2310-6003] vs. Open: $4264 [$3277-5143], p < 0.001). Outcomes after robotic-assisted inguinal hernia repair were similar to outcomes after laparoscopic or open repair. Longer operative duration during robotic repair may contribute to higher rates of skin and soft tissue infection. Higher cost should be considered, along with surgeon comfort level and patient preference when deciding whether inguinal hernia repair is approached robotically.

Timing matters: change depends on the stage of treatment in cognitive behavioral therapy for panic disorder with agoraphobia.

PubMed

Gloster, Andrew T; Klotsche, Jens; Gerlach, Alexander L; Hamm, Alfons; Ströhle, Andreas; Gauggel, Siegfried; Kircher, Tilo; Alpers, Georg W; Deckert, Jürgen; Wittchen, Hans-Ulrich

2014-02-01

The mechanisms of action underlying treatment are inadequately understood. This study examined 5 variables implicated in the treatment of panic disorder with agoraphobia (PD/AG): catastrophic agoraphobic cognitions, anxiety about bodily sensations, agoraphobic avoidance, anxiety sensitivity, and psychological flexibility. The relative importance of these process variables was examined across treatment phases: (a) psychoeducation/interoceptive exposure, (b) in situ exposure, and (c) generalization/follow-up. Data came from a randomized controlled trial of cognitive behavioral therapy for PD/AG (n = 301). Outcomes were the Panic and Agoraphobia Scale (Bandelow, 1995) and functioning as measured in the Clinical Global Impression scale (Guy, 1976). The effect of process variables on subsequent change in outcome variables was calculated using bivariate latent difference score modeling. Change in panic symptomatology was preceded by catastrophic appraisal and agoraphobic avoidance across all phases of treatment, by anxiety sensitivity during generalization/follow-up, and by psychological flexibility during exposure in situ. Change in functioning was preceded by agoraphobic avoidance and psychological flexibility across all phases of treatment, by fear of bodily symptoms during generalization/follow-up, and by anxiety sensitivity during exposure. The effects of process variables on outcomes differ across treatment phases and outcomes (i.e., symptomatology vs. functioning). Agoraphobic avoidance and psychological flexibility should be investigated and therapeutically targeted in addition to cognitive variables. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Serum Potassium, Mortality, and Kidney Outcomes in the Atherosclerosis Risk in Communities Study.

PubMed

Chen, Yan; Chang, Alex R; McAdams DeMarco, Mara A; Inker, Lesley A; Matsushita, Kunihiro; Ballew, Shoshana H; Coresh, Josef; Grams, Morgan E

2016-10-01

To investigate the association between serum potassium, mortality, and kidney outcomes in the general population and whether potassium-altering medications modify these associations. We studied 15,539 adults in the Atherosclerosis Risk in Communities Study. Cox proportional hazard regression was used to investigate the association of serum potassium at baseline (1987-1989), evaluated categorically (hypokalemia, <3.5 mmol/L; normokalemia, ≥3.5 and <5.5 mmol/L; hyperkalemia, ≥5.5 mmol/L) and continuously using linear spline terms (knots at 3.5 and 5.5 mmol/L), with mortality, sudden cardiac death, incident chronic kidney disease, and end-stage renal disease. The end date of follow-up for all outcomes was December 31, 2012. We also evaluated whether classes of potassium-altering medications modified the association between serum potassium and adverse outcomes. Overall, 413 (2.7%) of the participants had hypokalemia and 321 (2.1%) had hyperkalemia. In a fully adjusted model, hyperkalemia was significantly associated with mortality (hazard ratio, 1.24; 95% CI, 1.04-1.49) but not sudden cardiac death, chronic kidney disease, or end-stage renal disease. Hypokalemia as a categorical variable was not associated with any outcome; however, associations of hypokalemia with all-cause mortality and kidney outcomes were observed among those who were not taking potassium-wasting diuretics (all P for interaction, <.001). Higher values of serum potassium were associated with a higher risk of mortality in the general population. Lower levels of potassium were associated with adverse kidney outcomes and mortality among participants not taking potassium-wasting diuretics. Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Post-treatment Stage of Change Predicts 12-month Outcome of Treatment for Alcohol Problems

PubMed Central

Heather, Nick; McCambridge, Jim

2013-01-01

Aims: To evaluate relationships between clients' self-reported ‘stage of change’ and outcomes after treatment for alcohol problems. Methods: Using data from the ‘United Kingdom Alcohol Treatment Trial’, clients who had received at least one session of treatment and who had complete data (n = 392) entered the analysis. Two continuous measures of drinking behaviour (% days abstinent (PDA) and drinks per drinking day (DDD)) and categorical outcomes at the 12-month follow-up were compared between clients in Pre-action and Action stages of change at either pre- or post-treatment assessment. Multiple and logistic regression analyses examined the relationships between stage of change and treatment outcomes, evaluating the strength of these relationships by controlling for likely confounders. Results: Pre-treatment stage of change did not predict outcome but post-treatment stage of change predicted PDA and DDD at the 12-month follow-up. In unadjusted and adjusted analyses, clients in Action at post-treatment were two to three times more likely to show a favourable categorical outcome, variously defined, than those in Pre-action. There were no differences between clients who had received Motivational Enhancement Therapy and those who had received Social Behaviour and Network Therapy in proportions maintaining or moving towards Action from before to after treatment. Conclusions: These findings confirm previous reports that motivational variables predict outcome of treatment but add that such a relationship is seen for post-treatment stage of change. For therapists, it would seem important to monitor the client's stage of change—which in good clinical practice often occurs in informal ways—and have strategies to deal with low motivation to change whenever it occurs throughout treatment. The findings are also consistent with a ‘common factors’ perspective on effective treatment for alcohol problems. PMID:23408241

Association of low body temperature and poor outcomes in patients admitted with worsening heart failure: a substudy of the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial.

PubMed

Payvar, Saeed; Spertus, John A; Miller, Alan B; Casscells, S Ward; Pang, Peter S; Zannad, Faiez; Swedberg, Karl; Maggioni, Aldo P; Reid, Kimberly J; Gheorghiade, Mihai

2013-12-01

Risk stratification in patients admitted with worsening heart failure (HF) is essential for tailoring therapy and counselling. Risk models are available but rarely used, in part because many require laboratory and imaging results that are not routinely available. Body temperature is associated with prognosis in other illnesses, and we hypothesized that low body temperature would be associated with worse outcomes in patients admitted with worsening HF. The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial was an event-driven, randomized, double-blind, placebo-controlled study of tolvaptan in 4133 patients hospitalized for worsening HF with an EF <40%. Co-primary endpoints were all-cause mortality and cardiovascular (CV) death or HF rehospitalization. Body temperature was measured orally at randomization and entered in analyses both as a continuous variable and categorized into three groups (<36 °C, 36-36.5 °C, and >36.5 °C) using Cox regression models. The composite of CV death or HF rehospitalization occurred in 1544 patients within 1 year. For every 1 °C decrease in body temperature, the risk of adverse outcomes increased by 16% [hazard raio (HR) 1.16, 95% confidence interval (CI) 1.04-1.28], after adjustment for age, gender, race, systolic blood pressure, EF, blood urea nitrogen, and serum sodium. In fully adjusted analysis, the risk of adverse outcomes in the lowest body temperature group (<36 °C) was 51% higher than that of the index group (>36.5 °C) (HR 1.35, 95% CI 1.15-1.58). Low body temperature is an independent marker of poor cardiovascular outcomes in patients admitted with worsening HF and reduced EF.

Future technology in cochlear implants: assessing the benefit.

PubMed

Briggs, Robert J S

2011-05-01

It has been over 50 years since Djourno and Eyries first attempted electric stimulation in a patient with deafness. Over this time, the Cochlear Implant (CI) has become not only remarkably successful, but increasingly complex. Although the basic components of the system still comprise an implanted receiver stimulator and electrode, externally worn speech processor, microphone, control system, and power source, there are now several alternative designs of these components with different attributes that can be variably combined to meet the needs of specific patient groups. Development by the manufacturers has been driven both by these various patient needs, and also by the desire to achieve technological superiority, or at least differentiation, ultimately in pursuit of market share. Assessment of benefit is the responsibility of clinicians. It is incumbent on both industry and clinicians to ensure appropriate, safe, and affordable introduction of new technology. For example, experience with the totally implanted cochlear implant (TIKI) has demonstrated that quality of hearing is the over-riding consideration for CI users. To date, improved hearing outcomes have been achieved by improvements in: speech processing strategies; microphone technology; pre-processing strategies; electrode placement; bilateral implantation; use of a hearing aid in the opposite ear (bimodal stimulation); and the combination of electric and acoustic stimulation in the same ear. The resulting expansion of CI candidacy, with more residual hearing, further improves the outcomes achieved. Largely facilitated by advances in electronic capability and computerization, it can be expected that these improvements will continue. However, marked variability of results still occurs and we cannot assure any individual patient of their outcome. Realistic goals for implementation of new technology include: improved hearing in noise and music perception; effective invisible hearing (no external apparatus); automated fitting; and reduction in outcome variability. This paper provides examples of relevant potential future technologies that can be applied to reach these goals. In the quest for better outcomes, future technology must deliver improved reliability and usability for both clinicians and recipients that does not compromise safety and is affordable. One of the challenges related to the introduction of new technologies is the 'classification' of CI systems and the framework under which sufficient change and increased benefit can be demonstrated to establish a claim of 'new generation CI' and hence increased reimbursement from third-party payers. Significant improvements in hearing outcomes and quality of life associated with CI design changes are difficult to measure, particularly when there is such dramatic benefit from the intervention of cochlear implantation from the individual's perspective. Manufacturers and clinicians need to be objective and undertake appropriate safety studies and long-term and multi-centre clinical trials to ensure that the introduction of new technology is both safe and effective and supported by health systems worldwide.

Quantifying Geographic Variation in Health Care Outcomes in the United States before and after Risk-Adjustment.

PubMed

Rosenberg, Barry L; Kellar, Joshua A; Labno, Anna; Matheson, David H M; Ringel, Michael; VonAchen, Paige; Lesser, Richard I; Li, Yue; Dimick, Justin B; Gawande, Atul A; Larsson, Stefan H; Moses, Hamilton

2016-01-01

Despite numerous studies of geographic variation in healthcare cost and utilization at the local, regional, and state levels across the U.S., a comprehensive characterization of geographic variation in outcomes has not been published. Our objective was to quantify variation in US health outcomes in an all-payer population before and after risk-adjustment. We used information from 16 independent data sources, including 22 million all-payer inpatient admissions from the Healthcare Cost and Utilization Project (which covers regions where 50% of the U.S. population lives) to analyze 24 inpatient mortality, inpatient safety, and prevention outcomes. We compared outcome variation at state, hospital referral region, hospital service area, county, and hospital levels. Risk-adjusted outcomes were calculated after adjusting for population factors, co-morbidities, and health system factors. Even after risk-adjustment, there exists large geographical variation in outcomes. The variation in healthcare outcomes exceeds the well publicized variation in US healthcare costs. On average, we observed a 2.1-fold difference in risk-adjusted mortality outcomes between top- and bottom-decile hospitals. For example, we observed a 2.3-fold difference for risk-adjusted acute myocardial infarction inpatient mortality. On average a 10.2-fold difference in risk-adjusted patient safety outcomes exists between top and bottom-decile hospitals, including an 18.3-fold difference for risk-adjusted Central Venous Catheter Bloodstream Infection rates. A 3.0-fold difference in prevention outcomes exists between top- and bottom-decile counties on average; including a 2.2-fold difference for risk-adjusted congestive heart failure admission rates. The population, co-morbidity, and health system factors accounted for a range of R2 between 18-64% of variability in mortality outcomes, 3-39% of variability in patient safety outcomes, and 22-70% of variability in prevention outcomes. The amount of variability in health outcomes in the U.S. is large even after accounting for differences in population, co-morbidities, and health system factors. These findings suggest that: 1) additional examination of regional and local variation in risk-adjusted outcomes should be a priority; 2) assumptions of uniform hospital quality that underpin rationale for policy choices (such as narrow insurance networks or antitrust enforcement) should be challenged; and 3) there exists substantial opportunity for outcomes improvement in the US healthcare system.

Addressing the identification problem in age-period-cohort analysis: a tutorial on the use of partial least squares and principal components analysis.

PubMed

Tu, Yu-Kang; Krämer, Nicole; Lee, Wen-Chung

2012-07-01

In the analysis of trends in health outcomes, an ongoing issue is how to separate and estimate the effects of age, period, and cohort. As these 3 variables are perfectly collinear by definition, regression coefficients in a general linear model are not unique. In this tutorial, we review why identification is a problem, and how this problem may be tackled using partial least squares and principal components regression analyses. Both methods produce regression coefficients that fulfill the same collinearity constraint as the variables age, period, and cohort. We show that, because the constraint imposed by partial least squares and principal components regression is inherent in the mathematical relation among the 3 variables, this leads to more interpretable results. We use one dataset from a Taiwanese health-screening program to illustrate how to use partial least squares regression to analyze the trends in body heights with 3 continuous variables for age, period, and cohort. We then use another dataset of hepatocellular carcinoma mortality rates for Taiwanese men to illustrate how to use partial least squares regression to analyze tables with aggregated data. We use the second dataset to show the relation between the intrinsic estimator, a recently proposed method for the age-period-cohort analysis, and partial least squares regression. We also show that the inclusion of all indicator variables provides a more consistent approach. R code for our analyses is provided in the eAppendix.

Evaluation of stratification factors and score-scales in clinical trials of treatment of clinical mastitis in dairy cows.

PubMed

Hektoen, L; Ødegaard, S A; Løken, T; Larsen, S

2004-05-01

There is often a need to reduce sample size in clinical trials due to practical limitations and ethical considerations. Better comparability between treatment groups by use of stratification in the design, and use of continuous outcome variables in the evaluation of treatment results, are two methods that can be used in order to achieve this. In this paper the choice of stratification factors in trials of clinical mastitis in dairy cows is investigated, and two score-scales for evaluation of clinical mastitis are introduced. The outcome in 57 dairy cows suffering from clinical mastitis and included in a clinical trial comparing homeopathic treatment, placebo and a standard antibiotic treatment is investigated. The strata of various stratification factors are compared across treatments to determine which other factors influence outcome. The two score scales, measuring acute and chronic mastitis symptoms, respectively, are evaluated on their ability to differentiate between patients classified from clinical criteria as responders or non-responders to treatment. Differences were found between the strata of the factors severity of mastitis, lactation number, previous mastitis this lactation and bacteriological findings. These factors influence outcome of treatment and appear relevant as stratification factors in mastitis trials. Both score scales differentiated between responders and non-responders to treatment and were found useful for evaluation of mastitis and mastitis treatment.

Glycemic control and maternal and fetal outcomes in pregnant women with type 1 diabetes according to the type of basal insulin.

PubMed

Chico, A; Herranz, L; Corcoy, R; Ramírez, O; Goya, M M; Bellart, J; González-Romero, S; Codina, M; Sánchez, P; Cortázar, A; Acosta, D; Picón, M J; Rubio, J A; Megía, A; Sancho, M A; Balsells, M; Solá, E; González, N L; López-López, J

2016-11-01

To examine the potential role of the type of basal insulin on glycemic control and maternal and foetal outcomes in pregnant women with type 1 diabetes (T1DM). Retrospective cohort study of pregnancies attended at 18 Spanish tertiary hospitals. T1DM, singleton pregnancies, delivery between 2002-2010, and use of the same basal and prandial insulin from before pregnancy until delivery. A total of 1534 pregnancies were included. The basal insulin most commonly used was Neutral Protamine Hagedorn (NPH) (51.7%), followed by glargine (23.2%) and continuous subcutaneous insulin infusion (CSII) (21.1%). CSII users had longer diabetes duration. Multiple logistic regression analysis showed that CSII was independently associated with lower doses of insulin, higher glycated haemoglobin (HbA 1c ) in all trimesters, and higher rates of miscarriage, preterm birth and neonatal hypoglycemia. Glargine was related to a higher risk of preterm birth and a small-for-gestational age infant (SGA). The odds ratios (OR) of the associations between insulin type and clinical outcomes (from 0.642 to 4.894) have a relevant magnitude. In this observational study of pregnant women with T1DM, the type of basal insulin was independently associated with metabolic variables and foetal outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Kinetic Risk Factors of Running-Related Injuries in Female Recreational Runners.

PubMed

Napier, Christopher; MacLean, Christopher L; Maurer, Jessica; Taunton, Jack E; Hunt, Michael A

2018-05-30

Our objective was to prospectively investigate the association of kinetic variables with running-related injury (RRI) risk. Seventy-four healthy female recreational runners ran on an instrumented treadmill while 3D kinetic and kinematic data were collected. Kinetic outcomes were vertical impact transient, average vertical loading rate, instantaneous vertical loading rate, active peak, vertical impulse, and peak braking force (PBF). Participants followed a 15-week half-marathon training program. Exposure time (hours of running) was calculated from start of program until onset of injury, loss to follow-up, or end of program. After converting kinetic variables from continuous to ordinal variables based on tertiles, Cox proportional hazard models with competing risks were fit for each variable independently, before analysis in a forward stepwise multivariable model. Sixty-five participants were included in the final analysis, with a 33.8% injury rate. PBF was the only kinetic variable that was a significant predictor of RRI. Runners in the highest tertile (PBF <-0.27 BW) were injured at 5.08 times the rate of those in the middle tertile and 7.98 times the rate of those in the lowest tertile. When analyzed in the multivariable model, no kinetic variables made a significant contribution to predicting injury beyond what had already been accounted for by PBF alone. Findings from this study suggest PBF is associated with a significantly higher injury hazard ratio in female recreational runners and should be considered as a target for gait retraining interventions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Outcomes of endovascular interventions for TASC II B and C femoropopliteal lesions.

PubMed

Baril, Donald T; Marone, Luke K; Kim, Justine; Go, Michael R; Chaer, Rabih A; Rhee, Robert Y

2008-09-01

To evaluate outcomes of endovascular interventions on femoropopliteal occlusive disease and determine predictors of restenosis of Trans Atlantic Inter-Societal Consensus (TASC) II B and C lesions. All patients undergoing endovascular interventions for femoropopliteal occlusive disease between May 2003 and July 2007 were reviewed. Patient demographics, pre- and post-procedure ankle-brachial indices (ABI), and anatomic factors (including categorization by TASC II classification, lesion length, and runoff vessel status) were analyzed. Outcomes evaluated included freedom from restenoses, freedom from re-intervention, overall patency, and assisted-patency. A total of 237 total limbs were treated during the period reviewed. The study group included 108 TASC B and 32 TASC C limbs in 125 patients (mean age 73.1 +/- 10.4 years, male sex: 59%). Seventy-one percent of patients were Rutherford classification 2/3 while the remaining 29% were Rutherford classification 4/5. Mean follow-up period was 12.7 months (range, 1-52 m). Forty-one (41) limbs experienced restenosis or occlusion at a mean time of 8 months (range, 1-24 m). Freedom from restenosis/occlusion was 58.9% at 12 months and 47.9% at 24 months. Predictors of restenosis included a preoperative ABI <0.5 (hazard ratio [HR] 3.05, 95% confidence interval [CI] 1.36-6.86, P = .007) and hypercholesterolemia (HR 2.42, 95% CI 1.11-5.25, P = .025). Lesion length as a continuous variable (per centimeter) also correlated with a higher risk of restenosis (HR 1.06, 95% CI 1.00-1.12, P = .057). The overall assisted-primary and secondary-patency rates were 87% and 94% respectively at 3 years with no significant differences between TASC B and TASC C limbs. Endovascular interventions for TASC II B and C lesions are associated with restenosis/occlusion rates that are at least as good as those of open femoropopliteal bypass surgery from historical, previously published series. Furthermore, overall assisted-patency rates are excellent, although low preoperative ABIs continue to be associated with worse outcomes.

Interval estimation and optimal design for the within-subject coefficient of variation for continuous and binary variables

PubMed Central

Shoukri, Mohamed M; Elkum, Nasser; Walter, Stephen D

2006-01-01

Background In this paper we propose the use of the within-subject coefficient of variation as an index of a measurement's reliability. For continuous variables and based on its maximum likelihood estimation we derive a variance-stabilizing transformation and discuss confidence interval construction within the framework of a one-way random effects model. We investigate sample size requirements for the within-subject coefficient of variation for continuous and binary variables. Methods We investigate the validity of the approximate normal confidence interval by Monte Carlo simulations. In designing a reliability study, a crucial issue is the balance between the number of subjects to be recruited and the number of repeated measurements per subject. We discuss efficiency of estimation and cost considerations for the optimal allocation of the sample resources. The approach is illustrated by an example on Magnetic Resonance Imaging (MRI). We also discuss the issue of sample size estimation for dichotomous responses with two examples. Results For the continuous variable we found that the variance stabilizing transformation improves the asymptotic coverage probabilities on the within-subject coefficient of variation for the continuous variable. The maximum like estimation and sample size estimation based on pre-specified width of confidence interval are novel contribution to the literature for the binary variable. Conclusion Using the sample size formulas, we hope to help clinical epidemiologists and practicing statisticians to efficiently design reliability studies using the within-subject coefficient of variation, whether the variable of interest is continuous or binary. PMID:16686943