Bayesian Model Averaging for Propensity Score Analysis
ERIC Educational Resources Information Center
Kaplan, David; Chen, Jianshen
2013-01-01
The purpose of this study is to explore Bayesian model averaging in the propensity score context. Previous research on Bayesian propensity score analysis does not take into account model uncertainty. In this regard, an internally consistent Bayesian framework for model building and estimation must also account for model uncertainty. The…
Propensity Score Analysis in R: A Software Review
ERIC Educational Resources Information Center
Keller, Bryan; Tipton, Elizabeth
2016-01-01
In this article, we review four software packages for implementing propensity score analysis in R: "Matching, MatchIt, PSAgraphics," and "twang." After briefly discussing essential elements for propensity score analysis, we apply each package to a data set from the Early Childhood Longitudinal Study in order to estimate the…
Bayesian Propensity Score Analysis: Simulation and Case Study
ERIC Educational Resources Information Center
Kaplan, David; Chen, Cassie J. S.
2011-01-01
Propensity score analysis (PSA) has been used in a variety of settings, such as education, epidemiology, and sociology. Most typically, propensity score analysis has been implemented within the conventional frequentist perspective of statistics. This perspective, as is well known, does not account for uncertainty in either the parameters of the…
[Propensity score matching in SPSS].
Huang, Fuqiang; DU, Chunlin; Sun, Menghui; Ning, Bing; Luo, Ying; An, Shengli
2015-11-01
To realize propensity score matching in PS Matching module of SPSS and interpret the analysis results. The R software and plug-in that could link with the corresponding versions of SPSS and propensity score matching package were installed. A PS matching module was added in the SPSS interface, and its use was demonstrated with test data. Score estimation and nearest neighbor matching was achieved with the PS matching module, and the results of qualitative and quantitative statistical description and evaluation were presented in the form of a graph matching. Propensity score matching can be accomplished conveniently using SPSS software.
Leyrat, Clémence; Seaman, Shaun R; White, Ian R; Douglas, Ian; Smeeth, Liam; Kim, Joseph; Resche-Rigon, Matthieu; Carpenter, James R; Williamson, Elizabeth J
2017-01-01
Inverse probability of treatment weighting is a popular propensity score-based approach to estimate marginal treatment effects in observational studies at risk of confounding bias. A major issue when estimating the propensity score is the presence of partially observed covariates. Multiple imputation is a natural approach to handle missing data on covariates: covariates are imputed and a propensity score analysis is performed in each imputed dataset to estimate the treatment effect. The treatment effect estimates from each imputed dataset are then combined to obtain an overall estimate. We call this method MIte. However, an alternative approach has been proposed, in which the propensity scores are combined across the imputed datasets (MIps). Therefore, there are remaining uncertainties about how to implement multiple imputation for propensity score analysis: (a) should we apply Rubin's rules to the inverse probability of treatment weighting treatment effect estimates or to the propensity score estimates themselves? (b) does the outcome have to be included in the imputation model? (c) how should we estimate the variance of the inverse probability of treatment weighting estimator after multiple imputation? We studied the consistency and balancing properties of the MIte and MIps estimators and performed a simulation study to empirically assess their performance for the analysis of a binary outcome. We also compared the performance of these methods to complete case analysis and the missingness pattern approach, which uses a different propensity score model for each pattern of missingness, and a third multiple imputation approach in which the propensity score parameters are combined rather than the propensity scores themselves (MIpar). Under a missing at random mechanism, complete case and missingness pattern analyses were biased in most cases for estimating the marginal treatment effect, whereas multiple imputation approaches were approximately unbiased as long as the
A Bootstrap Procedure of Propensity Score Estimation
ERIC Educational Resources Information Center
Bai, Haiyan
2013-01-01
Propensity score estimation plays a fundamental role in propensity score matching for reducing group selection bias in observational data. To increase the accuracy of propensity score estimation, the author developed a bootstrap propensity score. The commonly used propensity score matching methods: nearest neighbor matching, caliper matching, and…
Propensity Score Analysis: An Alternative Statistical Approach for HRD Researchers
ERIC Educational Resources Information Center
Keiffer, Greggory L.; Lane, Forrest C.
2016-01-01
Purpose: This paper aims to introduce matching in propensity score analysis (PSA) as an alternative statistical approach for researchers looking to make causal inferences using intact groups. Design/methodology/approach: An illustrative example demonstrated the varying results of analysis of variance, analysis of covariance and PSA on a heuristic…
A Two-Step Bayesian Approach for Propensity Score Analysis: Simulations and Case Study
ERIC Educational Resources Information Center
Kaplan, David; Chen, Jianshen
2012-01-01
A two-step Bayesian propensity score approach is introduced that incorporates prior information in the propensity score equation and outcome equation without the problems associated with simultaneous Bayesian propensity score approaches. The corresponding variance estimators are also provided. The two-step Bayesian propensity score is provided for…
Statin use and kidney cancer outcomes: A propensity score analysis.
Nayan, Madhur; Finelli, Antonio; Jewett, Michael A S; Juurlink, David N; Austin, Peter C; Kulkarni, Girish S; Hamilton, Robert J
2016-11-01
Studies evaluating the association between statin use and survival outcomes in renal cell carcinoma have demonstrated conflicting results. Our objective was to evaluate this association in a large clinical cohort by using propensity score methods to reduce confounding from measured covariates. We performed a retrospective review of 893 patients undergoing nephrectomy for unilateral, M0 renal cell carcinoma between 2000 and 2014 at a tertiary academic center. Inverse probability of treatment weights were derived from a propensity score model based on clinical, surgical, and pathological characteristics. We used Cox proportional hazard models to evaluate the association between statin use and disease-free survival, cancer-specific survival, and overall survival in the sample weighted by the inverse probability of treatment weights. A secondary analysis was performed matching statin users 1:1 to statin nonusers on the propensity score. Of the 893 patients, 259 (29%) were on statins at the time of surgery. Median follow-up was 47 months (interquartile range: 20-80). Statin use was not significantly associated with disease-free survival (hazard ratio [HR] = 1.09, 95% CI: 0.65-1.81), cancer-specific survival (HR = 0.90, 95% CI: 0.40-2.01), or overall survival (HR = 0.89, 95% CI: 0.55-1.44). Similar results were observed when using propensity score matching. The present study found no significant association between statin use and kidney cancer outcomes. Population-based studies are needed to further evaluate the role of statins in kidney cancer therapy. Copyright © 2016 Elsevier Inc. All rights reserved.
A Two-Step Bayesian Approach for Propensity Score Analysis: Simulations and Case Study.
Kaplan, David; Chen, Jianshen
2012-07-01
A two-step Bayesian propensity score approach is introduced that incorporates prior information in the propensity score equation and outcome equation without the problems associated with simultaneous Bayesian propensity score approaches. The corresponding variance estimators are also provided. The two-step Bayesian propensity score is provided for three methods of implementation: propensity score stratification, weighting, and optimal full matching. Three simulation studies and one case study are presented to elaborate the proposed two-step Bayesian propensity score approach. Results of the simulation studies reveal that greater precision in the propensity score equation yields better recovery of the frequentist-based treatment effect. A slight advantage is shown for the Bayesian approach in small samples. Results also reveal that greater precision around the wrong treatment effect can lead to seriously distorted results. However, greater precision around the correct treatment effect parameter yields quite good results, with slight improvement seen with greater precision in the propensity score equation. A comparison of coverage rates for the conventional frequentist approach and proposed Bayesian approach is also provided. The case study reveals that credible intervals are wider than frequentist confidence intervals when priors are non-informative.
Methods for Constructing and Assessing Propensity Scores
Garrido, Melissa M; Kelley, Amy S; Paris, Julia; Roza, Katherine; Meier, Diane E; Morrison, R Sean; Aldridge, Melissa D
2014-01-01
Objectives To model the steps involved in preparing for and carrying out propensity score analyses by providing step-by-step guidance and Stata code applied to an empirical dataset. Study Design Guidance, Stata code, and empirical examples are given to illustrate (1) the process of choosing variables to include in the propensity score; (2) balance of propensity score across treatment and comparison groups; (3) balance of covariates across treatment and comparison groups within blocks of the propensity score; (4) choice of matching and weighting strategies; (5) balance of covariates after matching or weighting the sample; and (6) interpretation of treatment effect estimates. Empirical Application We use data from the Palliative Care for Cancer Patients (PC4C) study, a multisite observational study of the effect of inpatient palliative care on patient health outcomes and health services use, to illustrate the development and use of a propensity score. Conclusions Propensity scores are one useful tool for accounting for observed differences between treated and comparison groups. Careful testing of propensity scores is required before using them to estimate treatment effects. PMID:24779867
Myopia and cognitive dysfunction among elderly Chinese adults: a propensity score matching analysis.
Sun, Hong-Peng; Liu, Hu; Xu, Yong; Pan, Chen-Wei
2016-03-01
The association between myopia and cognitive dysfunction among elderly adults was assessed by applying a Propensity Score Matching (PSM) approach. This is a statistical method which allows investigators to estimate causal treatment effects using observational or nonrandomised data. The study was designed as a community-based cross-sectional study based on a Chinese cohort aged 60 years or older in China. Objective refraction was measured using an autorefractor and subjective refraction was used to refine vision, using the results of the objective refraction as the starting point. Myopia was defined as a spherical equivalent value of less than -0.50 dioptre (D) in the right eye. The Abbreviated Mental Test (AMT) was used for cognitive assessment. The propensity scores for myopia were formulated using 13 potential confounders. We matched the propensity scores for subjects with and without myopia within a caliper of 0.01 of logit function of propensity scores. About 4123 elderly adults who successfully completed the AMT were included in this analysis. The odds ratio (OR) of cognitive dysfunction for myopia before matching was 1.98 (95% confidence interval [CI] 1.61, 2.44; p < 0.001). There were significant covariate imbalances between comparison groups and after propensity score matching, covariate imbalance was significantly reduced. After propensity score matching, the OR of cognitive dysfunction was marginally significant and the magnitude of association was reduced (OR: 1.31 95% CI 1.00, 1.71; p = 0.05). Traditional multivariate logistic regression modelling found an OR of 1.52 (95% CI 1.23, 2.06; p < 0.001) after adjusting for the 13 potential confounders. Myopia was associated with a higher prevalence of cognitive dysfunction among elderly Chinese aged 60 years or older in China. The PSM approach may be a useful method to address selection bias in observational studies when randomised trials cannot ethically be conducted. © 2015 The Authors Ophthalmic
Using Propensity Score Analysis for Making Causal Claims in Research Articles
ERIC Educational Resources Information Center
Bai, Haiyan
2011-01-01
The central role of the propensity score analysis (PSA) in observational studies is for causal inference; as such, PSA is often used for making causal claims in research articles. However, there are still some issues for researchers to consider when making claims of causality using PSA results. This summary first briefly reviews PSA, followed by…
Pagès, Pierre-Benoit; Delpy, Jean-Philippe; Orsini, Bastien; Gossot, Dominique; Baste, Jean-Marc; Thomas, Pascal; Dahan, Marcel; Bernard, Alain
2016-04-01
Video-assisted thoracoscopic surgery (VATS) lobectomy has recently become the recommended approach for stage I non-small cell lung cancer. However, these guidelines are not based on any large randomized control trial. Our study used propensity scores and a sensitivity analysis to compare VATS lobectomy with open thoracotomy. From 2005 to 2012, 24,811 patients (95.1%) were operated on by open thoracotomy and 1,278 (4.9%) by VATS. The end points were 30-day postoperative death, postoperative complications, hospital stay, overall survival, and disease-free survival. Two propensity scores analyses were performed: matching and inverse probability of treatment weighting, and one sensitivity analysis to unmask potential hidden bias. A subgroup analysis was performed to compare "high-risk" with "low-risk" patients. Results are reported by odds ratios or hazard ratios and their 95% confidence intervals. Postoperative death was not significantly reduced by VATS whatever the analysis. Concerning postoperative complications, VATS significantly decreased the occurrence of atelectasis and pneumopathy with both analysis methods, but there were no differences in the occurrence of other postoperative complications. VATS did not provide a benefit for high-risk patients. The VATS approach decreased the hospital length of stay from 2.4 days (95% confidence interval, -1.7 to -3 days) to -4.68 days (95% confidence interval, -8.5 to 0.9 days). Overall survival and disease-free survival were not influenced by the surgical approach. The sensitivity analysis showed potential biases. The results must be interpreted carefully because of the differences observed according to the propensity scores method used. A multicenter randomized controlled trial is necessary to limit the biases. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
Austin, Peter C
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 (e.g., active treatment vs. control). The generalized propensity score is an extension of the propensity score for use with quantitative exposures (e.g., dose or quantity of medication, income, years of education). A crucial component of any propensity score analysis is that of balance assessment. This entails assessing the degree to which conditioning on the propensity score (via matching, weighting, or stratification) has balanced measured baseline covariates between exposure groups. Methods for balance assessment have been well described and are frequently implemented when using the propensity score with binary exposures. However, there is a paucity of information on how to assess baseline covariate balance when using the generalized propensity score. We describe how methods based on the standardized difference can be adapted for use with quantitative exposures when using the generalized propensity score. We also describe a method based on assessing the correlation between the quantitative exposure and each covariate in the sample when weighted using generalized propensity score -based weights. We conducted a series of Monte Carlo simulations to evaluate the performance of these methods. We also compared two different methods of estimating the generalized propensity score: ordinary least squared regression and the covariate balancing propensity score method. We illustrate the application of these methods using data on patients hospitalized with a heart attack with the quantitative exposure being creatinine level.
Milner, Allison; Aitken, Zoe; Krnjacki, Lauren; Bentley, Rebecca; Blakely, Tony; LaMontagne, Anthony D; Kavanagh, Anne M
2015-09-01
Equity and fairness at work are associated with a range of organizational and health outcomes. Past research suggests that workers with disabilities experience inequity in the workplace. It is difficult to conclude whether the presence of disability is the reason for perceived unfair treatment due to the possible confounding of effect estimates by other demographic or socioeconomic factors. The data source was the Household, Income, and Labor Dynamics in Australia (HILDA) survey (2001-2012). Propensity for disability was calculated from logistic models including gender, age, education, country of birth, and father's occupational skill level as predictors. We then used nearest neighbor (on propensity score) matched analysis to match workers with disabilities to workers without disability. Results suggest that disability is independently associated with lower fairness of pay after controlling for confounding factors in the propensity score matched analysis; although results do suggest less than half a standard deviation difference, indicating small effects. Similar results were apparent in standard multivariable regression models and alternative propensity score analyses (stratification, covariate adjustment using the propensity score, and inverse probability of treatment weighting). Whilst neither multivariable regression nor propensity scores adjust for unmeasured confounding, and there remains the potential for other biases, similar results for the two methodological approaches to confounder adjustment provide some confidence of an independent association of disability with perceived unfairness of pay. Based on this, we suggest that the disparity in the perceived fairness of pay between people with and without disabilities may be explained by worse treatment of people with disabilities in the workplace.
The performance of different propensity score methods for estimating marginal hazard ratios.
Austin, Peter C
2013-07-20
Propensity score methods are increasingly being used to reduce or minimize the effects of confounding when estimating the effects of treatments, exposures, or interventions when using observational or non-randomized data. Under the assumption of no unmeasured confounders, previous research has shown that propensity score methods allow for unbiased estimation of linear treatment effects (e.g., differences in means or proportions). However, in biomedical research, time-to-event outcomes occur frequently. There is a paucity of research into the performance of different propensity score methods for estimating the effect of treatment on time-to-event outcomes. Furthermore, propensity score methods allow for the estimation of marginal or population-average treatment effects. We conducted an extensive series of Monte Carlo simulations to examine the performance of propensity score matching (1:1 greedy nearest-neighbor matching within propensity score calipers), stratification on the propensity score, inverse probability of treatment weighting (IPTW) using the propensity score, and covariate adjustment using the propensity score to estimate marginal hazard ratios. We found that both propensity score matching and IPTW using the propensity score allow for the estimation of marginal hazard ratios with minimal bias. Of these two approaches, IPTW using the propensity score resulted in estimates with lower mean squared error when estimating the effect of treatment in the treated. Stratification on the propensity score and covariate adjustment using the propensity score result in biased estimation of both marginal and conditional hazard ratios. Applied researchers are encouraged to use propensity score matching and IPTW using the propensity score when estimating the relative effect of treatment on time-to-event outcomes. Copyright © 2012 John Wiley & Sons, Ltd.
Generalizing observational study results: applying propensity score methods to complex surveys.
Dugoff, Eva H; Schuler, Megan; Stuart, Elizabeth A
2014-02-01
To provide a tutorial for using propensity score methods with complex survey data. Simulated data and the 2008 Medical Expenditure Panel Survey. Using simulation, we compared the following methods for estimating the treatment effect: a naïve estimate (ignoring both survey weights and propensity scores), survey weighting, propensity score methods (nearest neighbor matching, weighting, and subclassification), and propensity score methods in combination with survey weighting. Methods are compared in terms of bias and 95 percent confidence interval coverage. In Example 2, we used these methods to estimate the effect on health care spending of having a generalist versus a specialist as a usual source of care. In general, combining a propensity score method and survey weighting is necessary to achieve unbiased treatment effect estimates that are generalizable to the original survey target population. Propensity score methods are an essential tool for addressing confounding in observational studies. Ignoring survey weights may lead to results that are not generalizable to the survey target population. This paper clarifies the appropriate inferences for different propensity score methods and suggests guidelines for selecting an appropriate propensity score method based on a researcher's goal. © Health Research and Educational Trust.
Temporary work and depressive symptoms: a propensity score analysis.
Quesnel-Vallée, Amélie; DeHaney, Suzanne; Ciampi, Antonio
2010-06-01
Recent decades have seen a tremendous increase in the complexity of work arrangements, through job sharing, flexible hours, career breaks, compressed work weeks, shift work, reduced job security, and part-time, contract and temporary work. In this study, we focus on one specific group of workers that arguably most embodies non-standard employment, namely temporary workers, and estimate the effect of this type of employment on depressive symptom severity. Accounting for the possibility of mental health selection into temporary work through propensity score analysis, we isolate the direct effects of temporary work on depressive symptoms with varying lags of time since exposure. We use prospective data from the U.S. National Longitudinal Survey of Youth 1979 (NLSY79), which has followed, longitudinally, from 1979 to the present, a nationally representative cohort of American men and women between 14 and 22 years of age in 1979. Three propensity score models were estimated, to capture the effect of different time lags (immediately following exposure, and 2 and 4 years post exposure) between the period of exposure to the outcome. The only significant effects were found among those who had been exposed to temporary work in the two years preceding the outcome measurement. These workers report 1.803 additional depressive symptoms from having experienced this work status (than if they had not been exposed). Moreover, this difference is both statistically and substantively significant, as it represents a 50% increase from the average level of depressive symptoms in this population. Copyright 2010 Elsevier Ltd. All rights reserved.
Generalizing Observational Study Results: Applying Propensity Score Methods to Complex Surveys
DuGoff, Eva H; Schuler, Megan; Stuart, Elizabeth A
2014-01-01
ObjectiveTo provide a tutorial for using propensity score methods with complex survey data. Data SourcesSimulated data and the 2008 Medical Expenditure Panel Survey. Study DesignUsing simulation, we compared the following methods for estimating the treatment effect: a naïve estimate (ignoring both survey weights and propensity scores), survey weighting, propensity score methods (nearest neighbor matching, weighting, and subclassification), and propensity score methods in combination with survey weighting. Methods are compared in terms of bias and 95 percent confidence interval coverage. In Example 2, we used these methods to estimate the effect on health care spending of having a generalist versus a specialist as a usual source of care. Principal FindingsIn general, combining a propensity score method and survey weighting is necessary to achieve unbiased treatment effect estimates that are generalizable to the original survey target population. ConclusionsPropensity score methods are an essential tool for addressing confounding in observational studies. Ignoring survey weights may lead to results that are not generalizable to the survey target population. This paper clarifies the appropriate inferences for different propensity score methods and suggests guidelines for selecting an appropriate propensity score method based on a researcher’s goal. PMID:23855598
Westreich, Daniel; Lessler, Justin; Funk, Michele Jonsson
2010-01-01
Summary Objective Propensity scores for the analysis of observational data are typically estimated using logistic regression. Our objective in this Review was to assess machine learning alternatives to logistic regression which may accomplish the same goals but with fewer assumptions or greater accuracy. Study Design and Setting We identified alternative methods for propensity score estimation and/or classification from the public health, biostatistics, discrete mathematics, and computer science literature, and evaluated these algorithms for applicability to the problem of propensity score estimation, potential advantages over logistic regression, and ease of use. Results We identified four techniques as alternatives to logistic regression: neural networks, support vector machines, decision trees (CART), and meta-classifiers (in particular, boosting). Conclusion While the assumptions of logistic regression are well understood, those assumptions are frequently ignored. All four alternatives have advantages and disadvantages compared with logistic regression. Boosting (meta-classifiers) and to a lesser extent decision trees (particularly CART) appear to be most promising for use in the context of propensity score analysis, but extensive simulation studies are needed to establish their utility in practice. PMID:20630332
TEMPORARY WORK AND DEPRESSIVE SYMPTOMS: A PROPENSITY SCORE ANALYSIS
Quesnel-Vallée, Amélie; DeHaney, Suzanne; Ciampi, Antonio
2013-01-01
Recent decades have seen a tremendous increase in the complexity of work arrangements, through job sharing, flexible hours, career breaks, compressed work weeks, shift work, reduced job security, and part-time, contract and temporary work. In this study, we focus on one specific group of workers that arguably most embodies nonstandard employment, namely temporary workers, and examine the consequences of this type of employment on depressive symptoms. This study aims to estimate the effect of being a temporary worker on depressive symptom severity. Accounting for the possibility of mental health selection into temporary work through propensity score analysis, we isolate the direct effects of temporary work on depressive symptoms with varying lags of time since exposure. We use prospective data from the U.S. National Longitudinal Survey of Youth 1979 (NLSY79), which has followed, longitudinally, from 1979 to the present, a nationally representative cohort of American men and women between 14 and 22 years of age in 1979. Three propensity score models were estimated, to capture the effect of different time lags (immediately following exposure, and 2 and 4 years post exposure) between the period of exposure to the outcome. The only significant effects were found among those who had been exposed to temporary work in the two years preceding the outcome measurement. These workers report 1.803 (95% CI 0.552; 3.055) additional depressive symptoms from having experienced this work status (than if they had not been exposed). Moreover, this difference is both statistically and substantively significant, as it represents a 50% increase from the average level of depressive symptoms in this population. PMID:20371142
The Propensity Score Analytical Framework: An Overview and Institutional Research Example
ERIC Educational Resources Information Center
Herzog, Serge
2014-01-01
Estimating the effect of campus math tutoring support, this study demonstrates the use of propensity score weighted and matched-data analysis and examines the correspondence with results from parametric regression analysis.
Advanced Issues in Propensity Scores: Longitudinal and Missing Data
ERIC Educational Resources Information Center
Kupzyk, Kevin A.; Beal, Sarah J.
2017-01-01
In order to investigate causality in situations where random assignment is not possible, propensity scores can be used in regression adjustment, stratification, inverse-probability treatment weighting, or matching. The basic concepts behind propensity scores have been extensively described. When data are longitudinal or missing, the estimation and…
Bohn, Justin; Eddings, Wesley; Schneeweiss, Sebastian
2017-03-15
Distributed networks of health-care data sources are increasingly being utilized to conduct pharmacoepidemiologic database studies. Such networks may contain data that are not physically pooled but instead are distributed horizontally (separate patients within each data source) or vertically (separate measures within each data source) in order to preserve patient privacy. While multivariable methods for the analysis of horizontally distributed data are frequently employed, few practical approaches have been put forth to deal with vertically distributed health-care databases. In this paper, we propose 2 propensity score-based approaches to vertically distributed data analysis and test their performance using 5 example studies. We found that these approaches produced point estimates close to what could be achieved without partitioning. We further found a performance benefit (i.e., lower mean squared error) for sequentially passing a propensity score through each data domain (called the "sequential approach") as compared with fitting separate domain-specific propensity scores (called the "parallel approach"). These results were validated in a small simulation study. This proof-of-concept study suggests a new multivariable analysis approach to vertically distributed health-care databases that is practical, preserves patient privacy, and warrants further investigation for use in clinical research applications that rely on health-care databases. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Bateman, Scot T; Borasino, Santiago; Asaro, Lisa A; Cheifetz, Ira M; Diane, Shelley; Wypij, David; Curley, Martha A Q
2016-03-01
The use of high-frequency oscillatory ventilation (HFOV) for acute respiratory failure in children is prevalent despite the lack of efficacy data. To compare the outcomes of patients with acute respiratory failure managed with HFOV within 24-48 hours of endotracheal intubation with those receiving conventional mechanical ventilation (CMV) and/or late HFOV. This is a secondary analysis of data from the RESTORE (Randomized Evaluation of Sedation Titration for Respiratory Failure) study, a prospective cluster randomized clinical trial conducted between 2009 and 2013 in 31 U.S. pediatric intensive care units. Propensity score analysis, including degree of hypoxia in the model, compared the duration of mechanical ventilation and mortality of patients treated with early HFOV matched with those treated with CMV/late HFOV. Among 2,449 subjects enrolled in RESTORE, 353 patients (14%) were ever supported on HFOV, of which 210 (59%) had HFOV initiated within 24-48 hours of intubation. The propensity score model predicting the probability of receiving early HFOV included 1,064 patients (181 early HFOV vs. 883 CMV/late HFOV) with significant hypoxia (oxygenation index ≥ 8). The degree of hypoxia was the most significant contributor to the propensity score model. After adjusting for risk category, early HFOV use was associated with a longer duration of mechanical ventilation (hazard ratio, 0.75; 95% confidence interval, 0.64-0.89; P = 0.001) but not with mortality (odds ratio, 1.28; 95% confidence interval, 0.92-1.79; P = 0.15) compared with CMV/late HFOV. In adjusted models including important oxygenation variables, early HFOV was associated with a longer duration of mechanical ventilation. These analyses make supporting the current approach to HFOV less convincing.
A Review of Propensity-Score Methods and Their Use in Cardiovascular Research.
Deb, Saswata; Austin, Peter C; Tu, Jack V; Ko, Dennis T; Mazer, C David; Kiss, Alex; Fremes, Stephen E
2016-02-01
Observational studies using propensity-score methods have been increasing in the cardiovascular literature because randomized controlled trials are not always feasible or ethical. However, propensity-score methods can be confusing, and the general audience may not fully understand the importance of this technique. The objectives of this review are to describe (1) the fundamentals of propensity score methods, (2) the techniques to assess for propensity-score model adequacy, (3) the 4 major methods for using the propensity score (matching, stratification, covariate adjustment, and inverse probability of treatment weighting [IPTW]) using examples from previously published cardiovascular studies, and (4) the strengths and weaknesses of these 4 techniques. Our review suggests that matching or IPTW using the propensity score have shown to be most effective in reducing bias of the treatment effect. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
Effect of Chronic Diseases on Work Productivity: A Propensity Score Analysis.
Fouad, Ahmed Mahmoud; Waheed, Amani; Gamal, Amira; Amer, Shaimaa Ahmed; Abdellah, Rasha Farouk; Shebl, Fatma Mohamed
2017-05-01
The aim of this study was to evaluate the effect of chronic disease(s) on work productivity. Using the Health & Work Performance Questionnaire, information was collected from 516 workers on chronic disease status and work productivity. Propensity-score matching was performed to identify matched-pairs of workers. In the propensity-score matched sample, workers with chronic diseases were more likely to have increased absenteeism and presenteeism rates, 6.34 and 2.36 times the rates if no chronic diseases, respectively. In addition, they had greater odds for getting negative critical work incidents and less odds for positive incidents than none or balanced status. Multimorbidity showed more significant increase in absenteeism and presenteeism rates, as well as increased odds for excess negative critical work incidents. Chronic disease(s) can significantly reduce work productivity by increasing absenteeism, presenteeism, and net negative critical incidents.
Tian, Yuxi; Schuemie, Martijn J; Suchard, Marc A
2018-06-22
Propensity score adjustment is a popular approach for confounding control in observational studies. Reliable frameworks are needed to determine relative propensity score performance in large-scale studies, and to establish optimal propensity score model selection methods. We detail a propensity score evaluation framework that includes synthetic and real-world data experiments. Our synthetic experimental design extends the 'plasmode' framework and simulates survival data under known effect sizes, and our real-world experiments use a set of negative control outcomes with presumed null effect sizes. In reproductions of two published cohort studies, we compare two propensity score estimation methods that contrast in their model selection approach: L1-regularized regression that conducts a penalized likelihood regression, and the 'high-dimensional propensity score' (hdPS) that employs a univariate covariate screen. We evaluate methods on a range of outcome-dependent and outcome-independent metrics. L1-regularization propensity score methods achieve superior model fit, covariate balance and negative control bias reduction compared with the hdPS. Simulation results are mixed and fluctuate with simulation parameters, revealing a limitation of simulation under the proportional hazards framework. Including regularization with the hdPS reduces commonly reported non-convergence issues but has little effect on propensity score performance. L1-regularization incorporates all covariates simultaneously into the propensity score model and offers propensity score performance superior to the hdPS marginal screen.
Lester L. Yuan,; Amina I. Pollard,; Carlisle, Daren M.
2009-01-01
Analyses of observational data can provide insights into relationships between environmental conditions and biological responses across a broader range of natural conditions than experimental studies, potentially complementing insights gained from experiments. However, observational data must be analyzed carefully to minimize the likelihood that confounding variables bias observed relationships. Propensity scores provide a robust approach for controlling for the effects of measured confounding variables when analyzing observational data. Here, we use propensity scores to estimate changes in mean invertebrate taxon richness in streams that have experienced insecticide concentrations that exceed aquatic life use benchmark concentrations. A simple comparison of richness in sites exposed to elevated insecticides with those that were not exposed suggests that exposed sites had on average 6.8 fewer taxa compared to unexposed sites. The presence of potential confounding variables makes it difficult to assert a causal relationship from this simple comparison. After controlling for confounding factors using propensity scores, the difference in richness between exposed and unexposed sites was reduced to 4.1 taxa, a difference that was still statistically significant. Because the propensity score analysis controlled for the effects of a wide variety of possible confounding variables, we infer that the change in richness observed in the propensity score analysis was likely caused by insecticide exposure.
Yuan, L.L.; Pollard, A.I.; Carlisle, D.M.
2009-01-01
Analyses of observational data can provide insights into relationships between environmental conditions and biological responses across a broader range of natural conditions than experimental studies, potentially complementing insights gained from experiments. However, observational data must be analyzed carefully to minimize the likelihood that confounding variables bias observed relationships. Propensity scores provide a robust approach for controlling for the effects of measured confounding variables when analyzing observational data. Here, we use propensity scores to estimate changes in mean invertebrate taxon richness in streams that have experienced insecticide concentrations that exceed aquatic life use benchmark concentrations. A simple comparison of richness in sites exposed to elevated insecticides with those that were not exposed suggests that exposed sites had on average 6.8 fewer taxa compared to unexposed sites. The presence of potential confounding variables makes it difficult to assert a causal relationship from this simple comparison. After controlling for confounding factors using propensity scores, the difference in richness between exposed and unexposed sites was reduced to 4.1 taxa, a difference that was still statistically significant. Because the propensity score analysis controlled for the effects of a wide variety of possible confounding variables, we infer that the change in richness observed in the propensity score analysis was likely caused by insecticide exposure. ?? 2009 SETAC.
Graphic report of the results from propensity score method analyses.
Shrier, Ian; Pang, Menglan; Platt, Robert W
2017-08-01
To increase transparency in studies reporting propensity scores by using graphical methods that clearly illustrate (1) the number of participant exclusions that occur as a consequence of the analytic strategy and (2) whether treatment effects are constant or heterogeneous across propensity scores. We applied graphical methods to a real-world pharmacoepidemiologic study that evaluated the effect of initiating statin medication on the 1-year all-cause mortality post-myocardial infarction. We propose graphical methods to show the consequences of trimming and matching on the exclusion of participants from the analysis. We also propose the use of meta-analytical forest plots to show the magnitude of effect heterogeneity. A density plot with vertical lines demonstrated the proportion of subjects excluded because of trimming. A frequency plot with horizontal lines demonstrated the proportion of subjects excluded because of matching. An augmented forest plot illustrates the amount of effect heterogeneity present in the data. Our proposed techniques present additional and useful information that helps readers understand the sample that is analyzed with propensity score methods and whether effect heterogeneity is present. Copyright © 2017 Elsevier Inc. All rights reserved.
An evaluation of bias in propensity score-adjusted non-linear regression models.
Wan, Fei; Mitra, Nandita
2018-03-01
Propensity score methods are commonly used to adjust for observed confounding when estimating the conditional treatment effect in observational studies. One popular method, covariate adjustment of the propensity score in a regression model, has been empirically shown to be biased in non-linear models. However, no compelling underlying theoretical reason has been presented. We propose a new framework to investigate bias and consistency of propensity score-adjusted treatment effects in non-linear models that uses a simple geometric approach to forge a link between the consistency of the propensity score estimator and the collapsibility of non-linear models. Under this framework, we demonstrate that adjustment of the propensity score in an outcome model results in the decomposition of observed covariates into the propensity score and a remainder term. Omission of this remainder term from a non-collapsible regression model leads to biased estimates of the conditional odds ratio and conditional hazard ratio, but not for the conditional rate ratio. We further show, via simulation studies, that the bias in these propensity score-adjusted estimators increases with larger treatment effect size, larger covariate effects, and increasing dissimilarity between the coefficients of the covariates in the treatment model versus the outcome model.
Propensity Scores in Pharmacoepidemiology: Beyond the Horizon.
Jackson, John W; Schmid, Ian; Stuart, Elizabeth A
2017-12-01
Propensity score methods have become commonplace in pharmacoepidemiology over the past decade. Their adoption has confronted formidable obstacles that arise from pharmacoepidemiology's reliance on large healthcare databases of considerable heterogeneity and complexity. These include identifying clinically meaningful samples, defining treatment comparisons, and measuring covariates in ways that respect sound epidemiologic study design. Additional complexities involve correctly modeling treatment decisions in the face of variation in healthcare practice, and dealing with missing information and unmeasured confounding. In this review, we examine the application of propensity score methods in pharmacoepidemiology with particular attention to these and other issues, with an eye towards standards of practice, recent methodological advances, and opportunities for future progress. Propensity score methods have matured in ways that can advance comparative effectiveness and safety research in pharmacoepidemiology. These include natural extensions for categorical treatments, matching algorithms that can optimize sample size given design constraints, weighting estimators that asymptotically target matched and overlap samples, and the incorporation of machine learning to aid in covariate selection and model building. These recent and encouraging advances should be further evaluated through simulation and empirical studies, but nonetheless represent a bright path ahead for the observational study of treatment benefits and harms.
Covariate Balance in Bayesian Propensity Score Approaches for Observational Studies
ERIC Educational Resources Information Center
Chen, Jianshen; Kaplan, David
2015-01-01
Bayesian alternatives to frequentist propensity score approaches have recently been proposed. However, few studies have investigated their covariate balancing properties. This article compares a recently developed two-step Bayesian propensity score approach to the frequentist approach with respect to covariate balance. The effects of different…
Ruiz-Bailén, Manuel; Expósito-Ruiz, Manuela; Castillo-Rivera, Ana-María; Rucabado-Aguilar, Luis; Ruiz-García, María Isabel; Ramos-Cuadra, José-Angel; Ruiz-Valverde, Andrés; Gómez-Jiménez, Javier; Benitez-Parejo, José-Luis; Cuñat de la Hoz, José; Abat, Francisco Felices; Valenzuela, Jesús Pérez
2010-05-01
The aim was to evaluate factors associated with the development of heart rupture in a Spanish registry of acute myocardial infarction (AMI) patients. This was a retrospective study of cohorts, including all patients diagnosed with AMI included in the ARIAM Spanish multicenter registry. The study period was from June 1996 to December 2005. The follow-up period was limited to the time of stay in intensive care or coronary care units. Multivariate logistic regression was used to study the factors associated with the development of heart rupture. A propensity score analysis was also performed to determine the involvement of beta blockers, ACE inhibitors, and fibrinolytics in the development of heart rupture. 16,815 AMI patients were included. Heart rupture occurred in 477 (2.8%). Heart rupture was associated with female gender, older age, the absence of previous infarct, and the administration of thrombolysis, while ACE inhibitors and beta blockers acted as protective variables. The propensity score analysis showed that fibrinolysis was a variable associated with heart rupture except in the younger subgroup and in the subgroup with less delay in administration. It was also found that beta blockers and ACE inhibitors are variables providing protection against heart rupture. Heart rupture is associated with older age, female gender, absence of previous infarct, and the administration of thrombolysis, while ACE inhibitors and beta blockers seem to prevent this complication.
A practical guide to propensity score analysis for applied clinical research.
Lee, Jaehoon; Little, Todd D
2017-11-01
Observational studies are often the only viable options in many clinical settings, especially when it is unethical or infeasible to randomly assign participants to different treatment régimes. In such case propensity score (PS) analysis can be applied to accounting for possible selection bias and thereby addressing questions of causal inference. Many PS methods exist, yet few guidelines are available to aid applied researchers in their conduct and evaluation of a PS analysis. In this article we give an overview of available techniques for PS estimation and application, balance diagnostic, treatment effect estimation, and sensitivity assessment, as well as recent advances. We also offer a tutorial that can be used to emulate the steps of PS analysis. Our goal is to provide information that will bring PS analysis within the reach of applied clinical researchers and practitioners. Copyright © 2017 Elsevier Ltd. All rights reserved.
Single Motherhood, Alcohol Dependence, and Smoking During Pregnancy: A Propensity Score Analysis.
Waldron, Mary; Bucholz, Kathleen K; Lian, Min; Lessov-Schlaggar, Christina N; Miller, Ruth Huang; Lynskey, Michael T; Knopik, Valerie S; Madden, Pamela A F; Heath, Andrew C
2017-09-01
Few studies linking single motherhood and maternal smoking during pregnancy consider correlated risk from problem substance use beyond history of smoking and concurrent use of alcohol. In the present study, we used propensity score methods to examine whether the risk of smoking during pregnancy associated with single motherhood is the result of potential confounders, including alcohol dependence. Data were drawn from mothers participating in a birth cohort study of their female like-sex twin offspring (n = 257 African ancestry; n = 1,711 European or other ancestry). We conducted standard logistic regression models predicting smoking during pregnancy from single motherhood at twins' birth, followed by propensity score analyses comparing single-mother and two-parent families stratified by predicted probability of single motherhood. In standard models, single motherhood predicted increased risk of smoking during pregnancy in European ancestry but not African ancestry families. In propensity score analyses, rates of smoking during pregnancy were elevated in single-mother relative to two-parent European ancestry families across much of the spectrum a priori risk of single motherhood. Among African ancestry families, within-strata comparisons of smoking during pregnancy by single-mother status were nonsignificant. These findings highlight single motherhood as a unique risk factor for smoking during pregnancy in European ancestry mothers, over and above alcohol dependence. Additional research is needed to identify risks, beyond single motherhood, associated with smoking during pregnancy in African ancestry mothers.
Can We Train Machine Learning Methods to Outperform the High-dimensional Propensity Score Algorithm?
Karim, Mohammad Ehsanul; Pang, Menglan; Platt, Robert W
2018-03-01
The use of retrospective health care claims datasets is frequently criticized for the lack of complete information on potential confounders. Utilizing patient's health status-related information from claims datasets as surrogates or proxies for mismeasured and unobserved confounders, the high-dimensional propensity score algorithm enables us to reduce bias. Using a previously published cohort study of postmyocardial infarction statin use (1998-2012), we compare the performance of the algorithm with a number of popular machine learning approaches for confounder selection in high-dimensional covariate spaces: random forest, least absolute shrinkage and selection operator, and elastic net. Our results suggest that, when the data analysis is done with epidemiologic principles in mind, machine learning methods perform as well as the high-dimensional propensity score algorithm. Using a plasmode framework that mimicked the empirical data, we also showed that a hybrid of machine learning and high-dimensional propensity score algorithms generally perform slightly better than both in terms of mean squared error, when a bias-based analysis is used.
Hunger and overweight in Canadian school-aged children: A propensity score matching analysis.
Sentenac, Mariane; Gariepy, Geneviève; McKinnon, Britt; Elgar, Frank J
2016-12-27
The last decade saw a higher prevalence of overweight reported among food-insecure families in Canada, but no robust evidence exists on the covariate-adjusted association in children. In this study, we examined the association between hunger and overweight in Canadian students, using a propensity score matching analysis to reduce confounding. This research used data from the 2009/2010 Canadian Health Behaviour in School-aged Children study on a representative national sample of students in Grades 6 through 10. Students self-reported their height and weight and how often they have gone to school or to bed hungry due to a lack of food at home. Multivariate logistic regression modeling was conducted on the total sample (N = 17,694) and on the sample matched on propensity scores (n = 7,788). The overall prevalence of overweight among students was 20.2% with a significant difference between students who reported hunger (24.0%; 95% CI: 22.1-26.0) and students who did not (19.0%; 95% CI: 17.9-20.2). Analysis on the matched sample revealed a significant association between hunger and overweight in children (adjusted odds ratio: 1.30; 95% CI: 1.12-1.50). A substantial number of Canadian students have reported being hungry because of a lack of food at home. These students are at increased risk of overweight, regardless of their social class. Child hunger and household food insecurity exist in Canada and constitute a call for policy action at a national level.
It's all about balance: propensity score matching in the context of complex survey data.
Lenis, David; Nguyen, Trang Quynh; Dong, Nianbo; Stuart, Elizabeth A
2017-12-27
Many research studies aim to draw causal inferences using data from large, nationally representative survey samples, and many of these studies use propensity score matching to make those causal inferences as rigorous as possible given the non-experimental nature of the data. However, very few applied studies are careful about incorporating the survey design with the propensity score analysis, which may mean that the results do not generate population inferences. This may be because few methodological studies examine how to best combine these methods. Furthermore, even fewer of them investigate different non-response mechanisms. This study examines methods for handling survey weights in propensity score matching analyses of survey data under different non-response mechanisms. Our main conclusions are: (i) whether the survey weights are incorporated in the estimation of the propensity score does not impact estimation of the population treatment effect, as long as good population treated-comparison balance is achieved on confounders, (ii) survey weights must be used in the outcome analysis, and (iii) the transferring of survey weights (i.e., assigning the weights of the treated units to the comparison units matched to them) can be beneficial under certain non-response mechanisms. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Yue, Lilly Q
2012-01-01
In the evaluation of medical products, including drugs, biological products, and medical devices, comparative observational studies could play an important role when properly conducted randomized, well-controlled clinical trials are infeasible due to ethical or practical reasons. However, various biases could be introduced at every stage and into every aspect of the observational study, and consequently the interpretation of the resulting statistical inference would be of concern. While there do exist statistical techniques for addressing some of the challenging issues, often based on propensity score methodology, these statistical tools probably have not been as widely employed in prospectively designing observational studies as they should be. There are also times when they are implemented in an unscientific manner, such as performing propensity score model selection for a dataset involving outcome data in the same dataset, so that the integrity of observational study design and the interpretability of outcome analysis results could be compromised. In this paper, regulatory considerations on prospective study design using propensity scores are shared and illustrated with hypothetical examples.
Kato, So; Chikuda, Hirotaka; Ohya, Junichi; Oichi, Takeshi; Matsui, Hiroki; Fushimi, Kiyohide; Takeshita, Katsushi; Tanaka, Sakae; Yasunaga, Hideo
2016-01-01
Although the negative aspects of blood transfusion are increasingly recognized, less is known about transfusion-related risks in spinal surgery. This study was designed to determine whether perioperative allogeneic blood transfusion is associated with increased risk of infectious complications after elective spinal surgery. A retrospective cohort study with propensity score matched analysis was carried out. Data of patients with spinal canal stenosis and spondylolisthesis who underwent elective lumbar surgeries (decompression or fusion) were obtained from the Diagnosis Procedure Combination database, a nationwide administrative inpatient database in Japan. Clinical outcomes included in-hospital death and the occurrence of infectious complications (surgical site infection [SSI], respiratory tract infection, urinary tract infection, and sepsis). Patients' clinical information, including sex, age, type of hospital, preoperative comorbidities, duration of anesthesia, cell saver use, and volume of allogeneic blood transfused, were investigated. Patients transfused with >840 mL (6 units) were excluded. Propensity scores for receiving transfusion were calculated, with one-to-one matching based on estimated propensity scores to adjust for patients' baseline characteristics. The proportions of complications were compared in patients with and without transfusions. This study was funded by grants from the Ministry of Health, Labour and Welfare, Japan. Of the 84,650 patients identified, 5,289 patients (6.1%) received transfusions, with 4,436 (5.2%) receiving up to 840 mL. One-to-one propensity score matching resulted in 4,275 pairs with and without transfusion. Patients transfused were at increased risk of SSI (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.4-2.5; p<.001) and urinary tract infection (OR, 2.5; 95% CI, 1.5-4.2; p<.001) than those not transfused. Allogeneic blood transfusion after elective lumbar surgery was associated with increased risks of SSI and
Propensity Score Matching within Prognostic Strata
ERIC Educational Resources Information Center
Kelcey, Ben
2013-01-01
A central issue in nonexperimental studies is identifying comparable individuals to remove selection bias. One common way to address this selection bias is through propensity score (PS) matching. PS methods use a model of the treatment assignment to reduce the dimensionality of the covariate space and identify comparable individuals. parallel to…
A Step-by-Step Guide to Propensity Score Matching in R
ERIC Educational Resources Information Center
Randolph, Justus J.; Falbe, Kristina; Manuel, Austin Kureethara; Balloun, Joseph L.
2014-01-01
Propensity score matching is a statistical technique in which a treatment case is matched with one or more control cases based on each case's propensity score. This matching can help strengthen causal arguments in quasi-experimental and observational studies by reducing selection bias. In this article we concentrate on how to conduct propensity…
Vercellino, Matteo; Sànchez, Federico Ariel; Boasi, Valentina; Perri, Dino; Tacchi, Chiara; Secco, Gioel Gabrio; Cattunar, Stefano; Pistis, Gianfranco; Mascelli, Giovanni
2017-04-05
European guidelines recommend the use of ticagrelor versus clopidogrel in patients with ST elevation myocardial infarction (STEMI). This recommendation is based on inconclusive results and subanalyses from clinical trials. Few data are available on the effects of ticagrelor in a real-world population. To compare the effects of ticagrelor and clopidogrel in a real-world STEMI population, we conducted a pre-post case-control study examining all patients with STEMI included in the Cardio-STEMI Sanremo registry between February 2011 and June 2013. Cases and controls were defined according to P2Y 12 inhibitors, correcting the bias due to lack of randomization by propensity score analysis. Ticagrelor was introduced in 2012 in both in-hospital and pre-hospital settings independently of this study. Of the 416 patients enrolled in the Cardio-STEMI registry, 401 with a definite diagnosis of STEMI were included in this study. One hundred forty-two patients received ticagrelor and 259 received clopidogrel. Regarding clinical presentation and procedural data, those in the ticagrelor group had lower CRUSADE scores (23 [14-36] vs 27 [18-38]; p = 0.015] but a higher proportion of radial access (33% vs 14%; p < 0.001), percutaneous coronary intervention (PCI; 92% vs 81 %; p = 0.002) and primary PCI ≤ 12 h (82% vs 66%; p = 0.001). The patients in the ticagrelor group had a higher procedural success rate (100% vs. 96%; p = 0.044). There was no difference in Bleeding Academic Research Consortium bleeding and in unadjusted incidence of hospital major adverse cardiovascular events (MACE; cardiac death, myocardial infarction, or stroke) but there was a significant reduction in unadjusted cardiac hospital death in the ticagrelor group (0.7% vs 5.4%; p = 0.024). After correcting for propensity score, hospital death (p = 0.22) and hospital MACE (p = 0.96) did not differ in both groups. The unadjusted survival at 1 year after STEMI was higher in the ticagrelor group (97
Propensity Score Matching: Retrospective Randomization?
Jupiter, Daniel C
Randomized controlled trials are viewed as the optimal study design. In this commentary, we explore the strength of this design and its complexity. We also discuss some situations in which these trials are not possible, or not ethical, or not economical. In such situations, specifically, in retrospective studies, we should make every effort to recapitulate the rigor and strength of the randomized trial. However, we could be faced with an inherent indication bias in such a setting. Thus, we consider the tools available to address that bias. Specifically, we examine matching and introduce and explore a new tool: propensity score matching. This tool allows us to group subjects according to their propensity to be in a particular treatment group and, in so doing, to account for the indication bias. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
ERIC Educational Resources Information Center
Dong, Nianbo; Lipsey, Mark
2014-01-01
When randomized control trials (RCT) are not feasible, researchers seek other methods to make causal inference, e.g., propensity score methods. One of the underlined assumptions for the propensity score methods to obtain unbiased treatment effect estimates is the ignorability assumption, that is, conditional on the propensity score, treatment…
Green, Kerry M.; Stuart, Elizabeth A.
2014-01-01
Objective This study provides guidance on how propensity score methods can be combined with moderation analyses (i.e., effect modification) to examine subgroup differences in potential causal effects in non-experimental studies. As a motivating example, we focus on how depression may affect subsequent substance use differently for men and women. Method Using data from a longitudinal community cohort study (N=952) of urban African Americans with assessments in childhood, adolescence, young adulthood and midlife, we estimate the influence of depression by young adulthood on substance use outcomes in midlife, and whether that influence varies by gender. We illustrate and compare five different techniques for estimating subgroup effects using propensity score methods, including separate propensity score models and matching for men and women, a joint propensity score model for men and women with matching separately and together by gender, and a joint male/female propensity score model that includes theoretically important gender interactions with matching separately and together by gender. Results Analyses showed that estimating separate models for men and women yielded the best balance and, therefore, is a preferred technique when subgroup analyses are of interest, at least in this data. Results also showed substance use consequences of depression but no significant gender differences. Conclusions It is critical to prespecify subgroup effects before the estimation of propensity scores and to check balance within subgroups regardless of the type of propensity score model used. Results also suggest that depression may affect multiple substance use outcomes in midlife for both men and women relatively equally. PMID:24731233
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Neely-Barnes, Susan L.; Graff, J. Carolyn
2011-01-01
This study examined whether siblings of children with disabilities have increased mental health problems, behavioral difficulties, or greater mental health service use as compared to siblings of children without disabilities. Data come from the 2006 National Health Interview Survey. Propensity score matching was used to complete the analysis.…
Austin, Peter C
2007-11-01
I conducted a systematic review of the use of propensity score matching in the cardiovascular surgery literature. I examined the adequacy of reporting and whether appropriate statistical methods were used. I examined 60 articles published in the Annals of Thoracic Surgery, European Journal of Cardio-thoracic Surgery, Journal of Cardiovascular Surgery, and the Journal of Thoracic and Cardiovascular Surgery between January 1, 2004, and December 31, 2006. Thirty-one of the 60 studies did not provide adequate information on how the propensity score-matched pairs were formed. Eleven (18%) of studies did not report on whether matching on the propensity score balanced baseline characteristics between treated and untreated subjects in the matched sample. No studies used appropriate methods to compare baseline characteristics between treated and untreated subjects in the propensity score-matched sample. Eight (13%) of the 60 studies explicitly used statistical methods appropriate for the analysis of matched data when estimating the effect of treatment on the outcomes. Two studies used appropriate methods for some outcomes, but not for all outcomes. Thirty-nine (65%) studies explicitly used statistical methods that were inappropriate for matched-pairs data when estimating the effect of treatment on outcomes. Eleven studies did not report the statistical tests that were used to assess the statistical significance of the treatment effect. Analysis of propensity score-matched samples tended to be poor in the cardiovascular surgery literature. Most statistical analyses ignored the matched nature of the sample. I provide suggestions for improving the reporting and analysis of studies that use propensity score matching.
Drawing causal inferences using propensity scores: a practical guide for community psychologists.
Lanza, Stephanie T; Moore, Julia E; Butera, Nicole M
2013-12-01
Confounding present in observational data impede community psychologists' ability to draw causal inferences. This paper describes propensity score methods as a conceptually straightforward approach to drawing causal inferences from observational data. A step-by-step demonstration of three propensity score methods-weighting, matching, and subclassification-is presented in the context of an empirical examination of the causal effect of preschool experiences (Head Start vs. parental care) on reading development in kindergarten. Although the unadjusted population estimate indicated that children with parental care had substantially higher reading scores than children who attended Head Start, all propensity score adjustments reduce the size of this overall causal effect by more than half. The causal effect was also defined and estimated among children who attended Head Start. Results provide no evidence for improved reading if those children had instead received parental care. We carefully define different causal effects and discuss their respective policy implications, summarize advantages and limitations of each propensity score method, and provide SAS and R syntax so that community psychologists may conduct causal inference in their own research.
Drawing Causal Inferences Using Propensity Scores: A Practical Guide for Community Psychologists
Lanza, Stephanie T.; Moore, Julia E.; Butera, Nicole M.
2014-01-01
Confounding present in observational data impede community psychologists’ ability to draw causal inferences. This paper describes propensity score methods as a conceptually straightforward approach to drawing causal inferences from observational data. A step-by-step demonstration of three propensity score methods – weighting, matching, and subclassification – is presented in the context of an empirical examination of the causal effect of preschool experiences (Head Start vs. parental care) on reading development in kindergarten. Although the unadjusted population estimate indicated that children with parental care had substantially higher reading scores than children who attended Head Start, all propensity score adjustments reduce the size of this overall causal effect by more than half. The causal effect was also defined and estimated among children who attended Head Start. Results provide no evidence for improved reading if those children had instead received parental care. We carefully define different causal effects and discuss their respective policy implications, summarize advantages and limitations of each propensity score method, and provide SAS and R syntax so that community psychologists may conduct causal inference in their own research. PMID:24185755
Sugihara, Masahiro
2010-01-01
In survival analysis, treatment effects are commonly evaluated based on survival curves and hazard ratios as causal treatment effects. In observational studies, these estimates may be biased due to confounding factors. The inverse probability of treatment weighted (IPTW) method based on the propensity score is one of the approaches utilized to adjust for confounding factors between binary treatment groups. As a generalization of this methodology, we developed an exact formula for an IPTW log-rank test based on the generalized propensity score for survival data. This makes it possible to compare the group differences of IPTW Kaplan-Meier estimators of survival curves using an IPTW log-rank test for multi-valued treatments. As causal treatment effects, the hazard ratio can be estimated using the IPTW approach. If the treatments correspond to ordered levels of a treatment, the proposed method can be easily extended to the analysis of treatment effect patterns with contrast statistics. In this paper, the proposed method is illustrated with data from the Kyushu Lipid Intervention Study (KLIS), which investigated the primary preventive effects of pravastatin on coronary heart disease (CHD). The results of the proposed method suggested that pravastatin treatment reduces the risk of CHD and that compliance to pravastatin treatment is important for the prevention of CHD. (c) 2009 John Wiley & Sons, Ltd.
ERIC Educational Resources Information Center
Austin, Peter C.
2011-01-01
The propensity score is the probability of treatment assignment conditional on observed baseline characteristics. The propensity score allows one to design and analyze an observational (nonrandomized) study so that it mimics some of the particular characteristics of a randomized controlled trial. In particular, the propensity score is a balancing…
Propensity Score Estimation with Data Mining Techniques: Alternatives to Logistic Regression
ERIC Educational Resources Information Center
Keller, Bryan S. B.; Kim, Jee-Seon; Steiner, Peter M.
2013-01-01
Propensity score analysis (PSA) is a methodological technique which may correct for selection bias in a quasi-experiment by modeling the selection process using observed covariates. Because logistic regression is well understood by researchers in a variety of fields and easy to implement in a number of popular software packages, it has…
Marital Dissolution and Major Depression in Midlife: A Propensity Score Analysis.
Sbarra, David A; Emery, Robert E; Beam, Christopher R; Ocker, Bailey L
2014-05-01
Marital dissolution is commonly assumed to cause increased depression among adults, but causality can be questioned based on directionality and third variable concerns. The present study improves upon past research by using a propensity score matching algorithm to identify a sub-sample of continuously married participants equivalent in divorce risk to participants who actually experienced separation/divorce between two waves of the nationally representative study, Midlife Development in the United States (MIDUS). After correcting for participants' propensity to separate/divorce, increased rates of depression at the second assessment were observed only among participants who were (a) depressed at the initial assessment, and (b) experienced a separation/divorce. Participants who were not depressed at the initial assessment but who experienced a separation/divorce were not at increased risk for a later major depressive disorder (MDE). Thus, both social selection and social causation contribute to the increased risk for a MDE found among separated/divorced adults.
Komiya, Kosaku; Oka, Hiroaki; Ohama, Minoru; Uchida, Masahiro; Miyajima, Hajime; Iwashita, Tomohiko; Okabe, Eiji; Shuto, Osamu; Matsumoto, Taisuke; Ishii, Hiroshi; Kadota, Jun-Ichi
2016-07-01
The incidence of pneumonia among elderly people is increasing in aged countries, and both pulmonologists and non-pulmonologists treat such patients. The aim of this study was to assess prognostic differences between elderly patients treated by pulmonologists and those treated by non-pulmonologists. This study was a retrospective cohort using a propensity score analysis. Patients 65 years of age or over with pneumonia were consecutively included. The propensity score was estimated based on the patient's background and severity of pneumonia. The difference in 30-day and 90-day mortality depending on the attending physician's specialty was analyzed after adjusting for other variables, including the propensity score. We assessed 68 and 182 patients treated by pulmonologists and non-pulmonologists, respectively. The pulmonologists tended to be in charge of patients with hypoxemia, chronic obstructive pulmonary disease or dementia without aspiration pneumonia or renal dysfunction (area under receiver operating characteristic curve to predict treatment by a pulmonologist according to the propensity score = 0.737, P < 0.001). In the multivariate analysis, white blood count cell (adjusted hazard ratio, 1.000, P = 0.030) and the serum albumin level (0.382, P = 0.001) were associated with 30-day mortality, and a bedridden status (3.000, P = 0.013) and the serum albumin level (0.382, P < 0.001) were associated with 90-day mortality; however, the attending physician's specialty was not associated with these prognoses. The overall prognosis of pneumonia in elderly patients may not necessarily improve, irrespective of treatment by pulmonologists, and host factors seemed to be associated with mortality. © 2014 John Wiley & Sons Ltd.
Stuart, Elizabeth A.; Lee, Brian K.; Leacy, Finbarr P.
2013-01-01
Objective Examining covariate balance is the prescribed method for determining when propensity score methods are successful at reducing bias. This study assessed the performance of various balance measures, including a proposed balance measure based on the prognostic score (also known as the disease-risk score), to determine which balance measures best correlate with bias in the treatment effect estimate. Study Design and Setting The correlations of multiple common balance measures with bias in the treatment effect estimate produced by weighting by the odds, subclassification on the propensity score, and full matching on the propensity score were calculated. Simulated data were used, based on realistic data settings. Settings included both continuous and binary covariates and continuous covariates only. Results The standardized mean difference in prognostic scores, the mean standardized mean difference, and the mean t-statistic all had high correlations with bias in the effect estimate. Overall, prognostic scores displayed the highest correlations of all the balance measures considered. Prognostic score measure performance was generally not affected by model misspecification and performed well under a variety of scenarios. Conclusion Researchers should consider using prognostic score–based balance measures for assessing the performance of propensity score methods for reducing bias in non-experimental studies. PMID:23849158
Kulaylat, Afif N; Rocourt, Dorothy V; Podany, Abigail B; Engbrecht, Brett W; Twilley, Marianne; Santos, Mary C; Cilley, Robert E; Hollenbeak, Christopher S; Dillon, Peter W
2017-05-01
The purpose of this analysis was to assess the burden of Clostridium difficile infection in the hospitalized pediatric surgical population and to characterize its influence on the costs of care. There were 313,664 patients age 1-18 years who underwent a general thoracic or abdominal procedure in the Kids' Inpatient Database during 2003, 2006, 2009, and 2012. Logistic regression was used to model factors associated with the development of C difficile infection. A propensity score-matching analysis was performed to evaluate the influence of C difficile infection on mortality, duration of stay, and costs in similar patient cohorts. Population weights were used to estimate the national excess burden of C difficile infection on these outcomes. The overall prevalence of C difficile infection in the sampled cohort was 0.30%, with an increasing trend of C difficile infection over time in non-children's hospitals (P < .001). C difficile infection was associated with younger age, nonelective procedures, increasing comorbidities, and urban teaching hospital status (P < .001). An estimated 1,438 children developed C difficile infection after operation. After propensity score matching, the mean excess duration of stay and costs attributable to C difficile infection were 5.8 days and $12,801 (P < .001), accounting for 8,295 days spent in the hospital and $18.4 million (2012 USD) in spending annually. C difficile infection is a relatively uncommon but costly complication after pediatric operative procedures. Given the increasing trend of C difficile infection among hospitalized surgical patients, there is substantial opportunity for reduction of inpatient burden and associated costs in this potentially preventable nosocomial infection. Copyright © 2016 Elsevier Inc. All rights reserved.
ERIC Educational Resources Information Center
Stone, Clement A.; Tang, Yun
2013-01-01
Propensity score applications are often used to evaluate educational program impact. However, various options are available to estimate both propensity scores and construct comparison groups. This study used a student achievement dataset with commonly available covariates to compare different propensity scoring estimation methods (logistic…
Westreich, Daniel; Lessler, Justin; Funk, Michele Jonsson
2010-08-01
Propensity scores for the analysis of observational data are typically estimated using logistic regression. Our objective in this review was to assess machine learning alternatives to logistic regression, which may accomplish the same goals but with fewer assumptions or greater accuracy. We identified alternative methods for propensity score estimation and/or classification from the public health, biostatistics, discrete mathematics, and computer science literature, and evaluated these algorithms for applicability to the problem of propensity score estimation, potential advantages over logistic regression, and ease of use. We identified four techniques as alternatives to logistic regression: neural networks, support vector machines, decision trees (classification and regression trees [CART]), and meta-classifiers (in particular, boosting). Although the assumptions of logistic regression are well understood, those assumptions are frequently ignored. All four alternatives have advantages and disadvantages compared with logistic regression. Boosting (meta-classifiers) and, to a lesser extent, decision trees (particularly CART), appear to be most promising for use in the context of propensity score analysis, but extensive simulation studies are needed to establish their utility in practice. Copyright (c) 2010 Elsevier Inc. All rights reserved.
Balancing Treatment and Control Groups in Quasi-Experiments: An Introduction to Propensity Scoring
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Connelly, Brian S.; Sackett, Paul R.; Waters, Shonna D.
2013-01-01
Organizational and applied sciences have long struggled with improving causal inference in quasi-experiments. We introduce organizational researchers to propensity scoring, a statistical technique that has become popular in other applied sciences as a means for improving internal validity. Propensity scoring statistically models how individuals in…
Mertens, Bart J. A.; Jacobs, Wilco C. H.; Brand, Ronald; Peul, Wilco C.
2014-01-01
We consider a re-analysis of the wait-and-see (control) arm of a recent clinical trial on sciatica. While the original randomised trial was designed to evaluate the public policy effect of a conservative wait-and-see approach versus early surgery, we investigate the impact of surgery at the individual patient level in a re-analysis of the wait-and-see group data. Both marginal structural model re-weighted estimates as well as propensity score adjusted analyses are presented. Results indicate that patients with high propensity to receive surgery may have beneficial effects at 2 years from delayed disc surgery. PMID:25353633
Root replacement using stentless valves in the small aortic root: a propensity score analysis.
Kunihara, Takashi; Schmidt, Kathrin; Glombitza, Petra; Dzindzibadze, Vachtang; Lausberg, Henning; Schäfers, Hans-Joachim
2006-10-01
Root replacement using a stentless bioprosthesis may be the optimal approach to avoid patient-prosthesis mismatch in patients with a small aortic root. Primary root replacement, however, is considered to be associated with increased surgical risk. We compared early outcome of full root replacement with a stentless bioprosthesis with that of aortic valve replacement with a stented bioprosthesis using propensity score-matching analysis. Of 231 patients undergoing elective, first-time aortic valve replacement with a small root (< or = 22 mm), 120 patients were selected using propensity score-matching analysis. They underwent either root replacement using a 23-mm stentless bioprosthesis (stentless group, n = 60) or supra-annular aortic valve replacement using a 21-mm stented bioprosthesis (stented group, n = 60). Preoperative characteristics and frequency of concomitant operations were identical. Duration of operation (196 +/- 54 versus 174 +/- 49 minutes), cardiopulmonary bypass (112 +/- 36 versus 91 +/- 33 minutes), and aortic cross-clamping (76 +/- 21 versus 61 +/- 21 minutes) were significantly longer in the stentless group. However, the need for perioperative transfusion and the incidence of postoperative reexploration for bleeding (3% versus 8%) was lower, and ventilation time was shorter. Mean duration of intensive care and hospital stay were also significantly shorter (2.3 +/- 1.7 versus 4.0 +/- 3.9 days, 8.9 +/- 3.1 versus 12.4 +/- 5.7 days). In-hospital mortality was identical (5% each). No independent predictor for in-hospital mortality was identified. Full root replacement using a stentless bioprosthesis does not increase postoperative morbidity or mortality of aortic valve replacement and may be advantageous in patients with a small aortic root.
Linden, Ariel
2017-08-01
When a randomized controlled trial is not feasible, health researchers typically use observational data and rely on statistical methods to adjust for confounding when estimating treatment effects. These methods generally fall into 3 categories: (1) estimators based on a model for the outcome using conventional regression adjustment; (2) weighted estimators based on the propensity score (ie, a model for the treatment assignment); and (3) "doubly robust" (DR) estimators that model both the outcome and propensity score within the same framework. In this paper, we introduce a new DR estimator that utilizes marginal mean weighting through stratification (MMWS) as the basis for weighted adjustment. This estimator may prove more accurate than treatment effect estimators because MMWS has been shown to be more accurate than other models when the propensity score is misspecified. We therefore compare the performance of this new estimator to other commonly used treatment effects estimators. Monte Carlo simulation is used to compare the DR-MMWS estimator to regression adjustment, 2 weighted estimators based on the propensity score and 2 other DR methods. To assess performance under varied conditions, we vary the level of misspecification of the propensity score model as well as misspecify the outcome model. Overall, DR estimators generally outperform methods that model one or the other components (eg, propensity score or outcome). The DR-MMWS estimator outperforms all other estimators when both the propensity score and outcome models are misspecified and performs equally as well as other DR estimators when only the propensity score is misspecified. Health researchers should consider using DR-MMWS as the principal evaluation strategy in observational studies, as this estimator appears to outperform other estimators in its class. © 2017 John Wiley & Sons, Ltd.
Can You Party Your Way to Better Health? A Propensity Score Analysis of Block Parties and Health
Dean, Lorraine T.; Hillier, Amy; Chau-Glendinning, Hang; Subramanian, SV; Williams, David R.; Kawachi, Ichiro
2015-01-01
While other indicators of social capital have been linked to health, the role of block parties on health in Black neighborhoods and on Black residents is understudied. Block parties exhibit several features of bonding social capital and are present in nearly 90% of Philadelphia’s predominantly Black neighborhoods. This analysis investigated: (1) whether or not block parties are an indicator of bonding social capital in Black neighborhoods; (2) the degree to which block parties might be related to self-rated health in the ways that other bonding social indicators are related to health; and (3) whether or not block parties are associated with average self-rated health for Black residents particularly. Using census tract-level indicators of bonding social capital and records of block parties from 2003 to 2008 for 381 Philadelphia neighborhoods (defined by census tracts), an ecological-level propensity score was generated to assess the propensity for a block party, adjusting for population demographics, neighborhood characteristics, neighborhood resources and violent crime. Results indicate that in multivariable regression, block parties were associated with increased bonding social capital in Black neighborhoods; however, the calculation of the average effect of the treatment on the treated (ATT) within each propensity score strata showed no effect of block parties on average self-rated health for Black residents. Block parties may be an indicator of bonding social capital in Philadelphia’s predominantly Black neighborhoods, but this analysis did not show a direct association between block parties and self-rated health for Black residents. Further research should consider what other health outcomes or behaviors block parties may be related to and how interventionists can leverage block parties for health promotion. PMID:26117555
Clinical Outcomes of Root Reimplantation and Bentall Procedure: Propensity Score Matching Analysis.
Lee, Heemoon; Cho, Yang Hyun; Sung, Kiick; Kim, Wook Sung; Park, Kay-Hyun; Jeong, Dong Seop; Park, Pyo Won; Lee, Young Tak
2018-03-26
This study aimed to evaluate the clinical outcomes of aortic root replacement(ARR) surgery:Root reimplantation as valve-sparing root replacement(VSR) and the Bentall procedure. We retrospectively reviewed 216 patients who underwent ARR between 1995 and 2013 at Samsung Medical Center. Patients were divided into two groups, depending on the procedure they underwent: Bentall(n=134) and VSR(n=82). The mean follow-up duration was 100.9±56.4 months. There were 2 early deaths in the Bentall group and none in the VSR group(p=0.53). Early morbidities were not different between the groups. Overall mortality was significantly lower in the VSR group (HR=0.12,p=0.04). Despite the higher reoperation rate in the VSR group(p=0.03), major adverse valve-related events(MAVRE) did not differ between the groups(p=0.28). Bleeding events were significantly higher in the Bentall group during follow-up(10 in Bentall group, 0 in VSR group, p=0.04). here were 6 thromboembolic events only in the Bentall group(p=0.11). We performed a propensity score matching analysis comparing the groups(134 Bentall vs 43 VSR). Matched analysis gave similar results, i.e. HR=0.17 and p=0.10 for overall mortality and HR=1.01 and p=0.99 for MAVRE. Although there was marginal significance in the propensity matched analysis, it is plausible to anticipate a survival benefit with VSR during long-term follow-up. Despite a higher reoperation for aortic valves, VSR can be a viable option in patients who decline life-long anticoagulation, especially the young or the patients in whom anticoagulation is contraindicated. Copyright © 2018. Published by Elsevier Inc.
Linden, Ariel; Adams, John L
2008-10-01
While the randomized controlled trial (RCT) remains the gold-standard study design for evaluating treatment effect, outcomes researchers turn to powerful quasi-experimental designs when only observational studies can be conducted. Within these designs, propensity score matching is one of the most popular to evaluate disease management (DM) programme effectiveness. Given that DM programmes generally have a much smaller number of participants than non-participants in the population, propensity score matching will typically result in all or nearly all participants finding successful matches, while most of the non-participants in the population remain unmatched and thereby excluded from the analysis. By excluding data from the unmatched population, the effect of non-treatment in the remaining population with the disease is not captured. In the present study, we examine changes in hospitalization rates stratified by propensity score quintiles across the entire population allowing us to gain insight as to how well the programme chose its participants, or if the programme could have been effective on those individuals not explicitly targeted for the intervention. These data indicate the presence of regression to the mean, and suggest that the DM programme may be overly limited to only the highest strata when there is evidence of a potential benefit for those in all the lower strata as well.
Yamashina, Takeshi; Fukuhara, Manabu; Maruo, Takanori; Tanke, Gensho; Marui, Saiko; Sada, Ryota; Taki, Mio; Ohara, Yoshiaki; Sakamoto, Azusa; Henmi, Shinichiro; Sawai, Yugo; Saito, Sumio; Nishijima, Norihiro; Nasu, Akihiro; Komekado, Hideyuki; Sekikawa, Akira; Asada, Masanori; Tumura, Takehiko; Kita, Ryuichi; Kimura, Toru; Osaki, Yukio
2017-01-01
Background and study aims Cold snare polypectomy (CSP) for small colorectal polyps has lower incidence of adverse events, especially delayed postpolypectomy bleeding (DPPB). However, few data are available on comparisons of the incidence of DPPB of CSP and hot polypectomy (HP). The aim of this study was to evaluate the incidence of DPPB after CSP and compare it with that of HP. A propensity score model was used as a secondary analysis. Patients and methods This was a retrospective cohort study conducted in a single municipal hospital. We identified 539 patients with colorectal polyps from 2 mm to 11 mm in size who underwent CSP (804 polyps in 330 patients) or HP (530 polyps in 209 patients) between July 2013 and June 2015. Results There were no cases of DPPB in the CSP group. Conversely, DPPB occurred in 4 patients (1.9 %) after HP, resulting in a significant difference between the CSP and HP groups (0.008 % vs 0 %, P = 0.02). Propensity score-matching analysis created 402 matched pairs, yielding a significantly higher DPPB rate in the HP group than CSP group (0.02 % vs 0 %, P = 0.04). However, significantly more patients in the CSP group had unclear horizontal margins that precluded assessment (83 vs 38 cases, P < 0.001). The retrieval failure rate was significantly higher in the CSP group than in the HP group (3 % vs 0.7 %, P = 0.01). Conclusions DPPB was less frequent with CSP than HP, as selected by the propensity score-matching model. Our findings indicate that CSP is recommended polypectomy in daily clinical setting. However, special care should be taken during polyp retrieval and horizontal margin assessment, and these issues could be taken into account in follow-up after CSP. PMID:28670615
Robinson, John W
2012-03-01
Propensity score models are increasingly used in observational comparative effectiveness studies to reduce confounding by covariates that are associated with both a study outcome and treatment choice. Any such potentially confounding covariate will bias estimation of the effect of treatment on the outcome, unless the distribution of that covariate is well-balanced between treatment and control groups. Constructing a subsample of treated and control subjects who are matched on estimated propensity scores is a means of achieving such balance for covariates that are included in the propensity score model. If, during study design, investigators assemble a comprehensive inventory of known and suspected potentially confounding covariates, examination of how well this inventory is covered by the chosen dataset yields an assessment of the extent of bias reduction that is possible by matching on estimated propensity scores. These considerations are explored by examining the designs of three recently published comparative effectiveness studies.
ERIC Educational Resources Information Center
Leow, Christine; Wen, Xiaoli; Korfmacher, Jon
2015-01-01
This article compares regression modeling and propensity score analysis as different types of statistical techniques used in addressing selection bias when estimating the impact of two-year versus one-year Head Start on children's school readiness. The analyses were based on the national Head Start secondary dataset. After controlling for…
Multilevel Propensity Score Matching within and across Schools
ERIC Educational Resources Information Center
Kelcey, Benjamin
2011-01-01
A central issue in nonexperimental studies is the identification of comparable individuals (e.g. students) to remove selection bias. One such increasingly common method to identify comparable individuals and address selection bias is the propensity score (PS). PS methods rely on a model of the treatment assignment to identify comparable…
Impacts of Playing after School on Academic Performance: A Propensity Score Matching Approach
ERIC Educational Resources Information Center
Li, Yajuan; Palma, Marco A.; Xu, Zhicheng Phil
2017-01-01
We present a plausible causal analysis of the impact of playing after school on academic performance and investigate parental support as a potential channel. We exploit the data from the 2011 Trends in International Mathematics and Science Survey to evaluate the effects by using a propensity score matching approach. The results show that playing…
Methamphetamine Users Have Increased Dental Disease: A Propensity Score Analysis.
Shetty, V; Harrell, L; Clague, J; Murphy, D A; Dye, B A; Belin, T R
2016-07-01
Methamphetamine (MA) users are assumed to have a high burden of tooth decay. Less clear is how the distribution and severity of dental caries in MA users differ from the general population. Using a covariate-balancing propensity score strategy, we investigated the differential effects of MA use on dental caries by comparing the patterns of decayed, missing, and filled teeth in a community sample of 571 MA users with a subset of 2,755 demographically similar control individuals selected from a National Health and Nutrition Examination Survey (NHANES) cohort. Recruited over a 2-y period with a stratified sampling protocol, the MA users underwent comprehensive dental examinations by 3 trained and calibrated dentists using NHANES protocols. Propensity scores were estimated with logistic regression based on background characteristics, and a subset of closely matched subjects was stratified into quintiles for comparisons. MA users were twice as likely to have untreated caries (odds ratio [OR] = 2.08; 95% confidence interval [95% CI]: 1.55 to 2.78) and 4 times more likely to have caries experience (OR = 4.06; 95% CI: 2.24 to 7.34) than the control group of NHANES participants. Additionally, MA users were twice as likely to have 2 more decayed, missing, or filled teeth (OR = 2.08; 95% CI: 1.29 to 2.79) than the NHANES participants. The differential involvement of the teeth surfaces in MA users was quite distinctive, with carious surface involvement being highest for the maxillary central incisors, followed by maxillary posterior premolars and molars. Users injecting MA had significantly higher rates of tooth decay compared with noninjectors (P = 0.04). Although MA users experienced decayed and missing dental surfaces more frequently than NHANES participants, NHANES participants had more restored surfaces, especially on molars. The high rates and distinctive patterns of dental caries observed could be used 1) to alert dentists to covert MA use in their patients and 2) as
Olthof, Dominique C; Joosse, Pieter; Bossuyt, Patrick M M; de Rooij, Philippe P; Leenen, Loek P H; Wendt, Klaus W; Bloemers, Frank W; Goslings, J Carel
2016-05-01
Non-operative management (NOM) is the standard of care in hemodynamically stable patients with blunt splenic injury after trauma. Splenic artery embolization (SAE) is reported to increase observation success rate. Studies demonstrating improved splenic salvage rates with SAE primarily compared SAE with historical controls. The aim of this study was to investigate whether SAE improves success rate compared to observation alone in contemporaneous patients with blunt splenic injury. We included adult patients with blunt splenic injury admitted to five Level 1 Trauma Centers between January 2009 and December 2012 and selected for NOM. Successful treatment was defined as splenic salvage and no splenic re-intervention. We calculated propensity scores, expressing the probability of undergoing SAE, using multivariable logistic regression and created five strata based on the quintiles of the propensity score distribution. A weighted relative risk (RR) was calculated across strata to express the chances of success with SAE. Two hundred and six patients were included in the study. Treatment was successful in 180 patients: 134/146 (92 %) patients treated with observation and 48/57 (84 %) patients treated with SAE. The weighted RR for success with SAE was 1.17 (0.94-1.45); for complications, the weighted RR was 0.71 (0.41-1.22). The mean number of transfused blood products was 4.4 (SD 9.9) in the observation group versus 9.1 (SD 17.2) in the SAE group. After correction for confounders with propensity score stratification technique, there was no significant difference between embolization and observation alone with regard to successful treatment in patients with blunt splenic injury after trauma.
Minakata, Kenji; Tanaka, Shiro; Tamura, Nobushige; Yanagi, Shigeki; Ohkawa, Yohei; Okonogi, Shuichi; Kaneko, Tatsuo; Usui, Akihiko; Abe, Tomonobu; Shimamoto, Mitsuomi; Takahara, Yoshiharu; Yamanaka, Kazuo; Yaku, Hitoshi; Sakata, Ryuzo
2017-07-25
The aim of this study was to assess the long-term outcomes of aortic valve replacement (AVR) with either mechanical or bioprosthetic valves according to age at operation.Methods and Results:A total of 1,002 patients (527 mechanical valves and 475 bioprosthetic valves) undergoing first-time AVR were categorized according to age at operation: group Y, age <60 years; group M, age 60-69 years; and group O, age ≥70 years). Outcomes were compared on propensity score analysis (adjusted for 28 variables). Hazard ratio (HR) was calculated using the Cox regression model with adjustment for propensity score with bioprosthetic valve as a reference (HR=1). There were no significant differences in overall mortality between mechanical and bioprosthetic valves for all age groups. Valve-related mortality was significantly higher for mechanical valves in group O (HR, 2.53; P=0.02). Reoperation rate was significantly lower for mechanical valves in group Y (HR, 0.16; P<0.01) and group M (no events for mechanical valves). Although the rate of thromboembolic events was higher in mechanical valves in group Y (no events for tissue valves) and group M (HR, 9.05; P=0.03), there were no significant differences in bleeding events between all age groups. The type of prosthetic valve used in AVR does not significantly influence overall mortality.
Austin, Peter C
2008-09-01
Propensity-score matching is frequently used in the cardiology literature. Recent systematic reviews have found that this method is, in general, poorly implemented in the medical literature. The study objective was to examine the quality of the implementation of propensity-score matching in the general cardiology literature. A total of 44 articles published in the American Heart Journal, the American Journal of Cardiology, Circulation, the European Heart Journal, Heart, the International Journal of Cardiology, and the Journal of the American College of Cardiology between January 1, 2004, and December 31, 2006, were examined. Twenty of the 44 studies did not provide adequate information on how the propensity-score-matched pairs were formed. Fourteen studies did not report whether matching on the propensity score balanced baseline characteristics between treated and untreated subjects in the matched sample. Only 4 studies explicitly used statistical methods appropriate for matched studies to compare baseline characteristics between treated and untreated subjects. Only 11 (25%) of the 44 studies explicitly used statistical methods appropriate for the analysis of matched data when estimating the effect of treatment on the outcomes. Only 2 studies described the matching method used, assessed balance in baseline covariates by appropriate methods, and used appropriate statistical methods to estimate the treatment effect and its significance. Application of propensity-score matching was poor in the cardiology literature. Suggestions for improving the reporting and analysis of studies that use propensity-score matching are provided.
Saito, Hirokazu; Kadono, Yoshihiro; Kamikawa, Kentaro; Urata, Atsushi; Imamura, Haruo; Matsushita, Ikuo; Kakuma, Tatsuyuki; Tada, Shuji
2018-02-15
Objective Single-stage endoscopic stone removal for choledocholithiasis is an advantageous approach because it is associated with a shorter hospital stay; however, few studies have reported the incidence of complications related to this procedure in detail. The aim of this study was to examine the incidence of complications and efficacy of this procedure. Methods This retrospective study investigated the incidence of complications in 345 patients with naive papilla who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis at three institutions between April 2014 and March 2016 by a propensity score analysis. The efficacy of single-stage endoscopic stone removal was assessed based on a hospital stay of within 7 days and the number of ERCP attempts. Results Among 114 patients who underwent single-stage endoscopic stone removal, 15 patients (13.2%) experienced complications. Among the remaining 231 patients in the two-stage endoscopic stone removal group, complications were observed in 17 patients (7.4%). The propensity score analysis, which was adjusted for confounding factors, revealed that single-stage endoscopic stone removal was not a significant risk factor for complications (p=0.52). In patients in whom >10 min was required for deep cannulation, single-stage endoscopic stone removal was not a significant risk factor for complications in the propensity score analysis (p=0.37). In the single-stage group, the proportion of patients with a hospital stay of within 7 days was significantly higher and the number of ERCP attempts was significantly lower in comparison to the two-stage group (p <0.0001 and <0.0001, respectively). Conclusion Single-stage endoscopic stone removal did not increase the incidence of complications associated with ERCP and was effective for reducing the hospital stay and the number of ERCP attempts.
Saito, Hirokazu; Kadono, Yoshihiro; Kamikawa, Kentaro; Urata, Atsushi; Imamura, Haruo; Matsushita, Ikuo; Kakuma, Tatsuyuki; Tada, Shuji
2017-01-01
Objective Single-stage endoscopic stone removal for choledocholithiasis is an advantageous approach because it is associated with a shorter hospital stay; however, few studies have reported the incidence of complications related to this procedure in detail. The aim of this study was to examine the incidence of complications and efficacy of this procedure. Methods This retrospective study investigated the incidence of complications in 345 patients with naive papilla who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis at three institutions between April 2014 and March 2016 by a propensity score analysis. The efficacy of single-stage endoscopic stone removal was assessed based on a hospital stay of within 7 days and the number of ERCP attempts. Results Among 114 patients who underwent single-stage endoscopic stone removal, 15 patients (13.2%) experienced complications. Among the remaining 231 patients in the two-stage endoscopic stone removal group, complications were observed in 17 patients (7.4%). The propensity score analysis, which was adjusted for confounding factors, revealed that single-stage endoscopic stone removal was not a significant risk factor for complications (p=0.52). In patients in whom >10 min was required for deep cannulation, single-stage endoscopic stone removal was not a significant risk factor for complications in the propensity score analysis (p=0.37). In the single-stage group, the proportion of patients with a hospital stay of within 7 days was significantly higher and the number of ERCP attempts was significantly lower in comparison to the two-stage group (p <0.0001 and <0.0001, respectively). Conclusion Single-stage endoscopic stone removal did not increase the incidence of complications associated with ERCP and was effective for reducing the hospital stay and the number of ERCP attempts. PMID:29151506
Ward, Jeffrey T; Krohn, Marvin D; Gibson, Chris L
2014-02-01
This study uses a life course framework to investigate how police contacts may serve as a potential turning point in a violent crime trajectory. Drawing on the central ideas from deterrence and labeling theories, we determine whether individuals on different violent offending trajectories increase or decrease their offending following a police contact. Analyzing nine waves of data from the Rochester Youth Development Study, an integrated propensity score matching and latent class growth model was used. First, three violent trajectory groups emerged including high offenders, non-offenders, and low offenders. Second, after accounting for selection bias using propensity score matching procedures, experiencing a police contact increased the likelihood of future violent offending for the entire sample and for those who were on a low violent-offending trajectory specifically. These findings are interpreted as partial support for labeling theory. Limitations of the study and directions for future research are discussed.
Martínez-Ramos, D; Escrig-Sos, J; Miralles-Tena, J M; Rivadulla-Serrano, M I; Daroca-José, J M; Salvador Sanchís, J L
2008-07-01
surgeon influence on colorectal cancer surgery outcomes has been repeatedly studied in the scientific literature, but conclusions have been contradictory. Here we study whether surgeon specialization is a determinant factor for outcome in these patients. The importance of propensity scores (PS) in surgical research is also studied. a retrospective study was performed and medical records were reviewed for 236 patients who were intervened for colon cancer in Castellon General Hospital (Spain). Cases were divided into two groups (specialist and non-specialist surgeons), and both 5-year surveillance and disease free survival were compared. Comparisons were first made with no adjustments, and then subsequently using PS analysis. the initial (non-adjusted) analysis was clearly favourable for the specialist surgeon group (5-year surveillance, 64.3 vs. 79.3%, p = 0.028). After adjusting for PS no statistical significance was obtained. surgeon specialization had no significant impact on patient outcome after colon cancer surgery. Propensity score analysis is an important tool in the analysis of surgical non-randomized studies, particularly when events under scrutiny are rare.
Giordano, Salvatore; Schaverien, Mark; Garvey, Patrick B; Baumann, Donald P; Liu, Jun; Butler, Charles E
2017-06-01
We hypothesized that elderly patients (≥65 years) experience worse outcomes following abdominal wall reconstruction (AWR) for hernia or oncologic resection. We included all consecutive patients who underwent complex AWR using acellular dermal matrix (ADM) between 2005 and 2015. Propensity score analysis was performed for risk adjustment in multivariable analysis and for one-to-one matching. The primary outcome was hernia recurrence; the secondary outcomes included surgical site occurrence (SSO) and bulging. Mean follow-up for the 511 patients was 31.4 months; 184 (36%) patients were elderly. The elderly and non-elderly groups had similar rates of hernia recurrence (7.6% vs 10.1%, respectively; p = 0.43) and SSO (24.5% vs 23.5%, respectively; p = 0.82). Bulging occurred significantly more often in elderly patients (6.5% vs 2.8%, respectively; p = 0.04). After adjustment through the propensity score, which included 130 pairs, these results persisted. Contrary to our hypothesis, elderly patients did not have worse outcomes in AWR with ADM. Surgeons should not deny elderly patients AWR solely because of their age. Copyright © 2016 Elsevier Inc. All rights reserved.
Andersen, Lars W; Kurth, Tobias; Chase, Maureen; Berg, Katherine M; Cocchi, Michael N; Callaway, Clifton
2016-01-01
Objectives To evaluate whether patients who experience cardiac arrest in hospital receive epinephrine (adrenaline) within the two minutes after the first defibrillation (contrary to American Heart Association guidelines) and to evaluate the association between early administration of epinephrine and outcomes in this population. Design Prospective observational cohort study. Setting Analysis of data from the Get With The Guidelines-Resuscitation registry, which includes data from more than 300 hospitals in the United States. Participants Adults in hospital who experienced cardiac arrest with an initial shockable rhythm, including patients who had a first defibrillation within two minutes of the cardiac arrest and who remained in a shockable rhythm after defibrillation. Intervention Epinephrine given within two minutes after the first defibrillation. Main outcome measures Survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and survival to hospital discharge with a good functional outcome. A propensity score was calculated for the receipt of epinephrine within two minutes after the first defibrillation, based on multiple characteristics of patients, events, and hospitals. Patients who received epinephrine at either zero, one, or two minutes after the first defibrillation were then matched on the propensity score with patients who were “at risk” of receiving epinephrine within the same minute but who did not receive it. Results 2978patients were matched on the propensity score, and the groups were well balanced. 1510 (51%) patients received epinephrine within two minutes after the first defibrillation, which is contrary to current American Heart Association guidelines. Epinephrine given within the first two minutes after the first defibrillation was associated with decreased odds of survival in the propensity score matched analysis (odds ratio 0.70, 95% confidence interval 0.59 to 0.82; P<0.001). Early epinephrine
ERIC Educational Resources Information Center
Okurut, Jeje Moses
2018-01-01
The impact of automatic promotion practice on students dropping out of Uganda's primary education was assessed using propensity score in difference in differences analysis technique. The analysis strategy was instrumental in addressing the selection bias problem, as well as biases arising from common trends over time, and permanent latent…
Amar, David; Zhang, Hao; Pedoto, Alessia; Desiderio, Dawn P; Shi, Weiji; Tan, Kay See
2017-07-01
Protective lung ventilation (PLV) during one-lung ventilation (OLV) for thoracic surgery is frequently recommended to reduce pulmonary complications. However, limited outcome data exist on whether PLV use during OLV is associated with less clinically relevant pulmonary morbidity after lung resection. Intraoperative data were prospectively collected in 1080 patients undergoing pulmonary resection with OLV, intentional crystalloid restriction, and mechanical ventilation to maintain inspiratory peak airway pressure <30 cm H2O. Other ventilator settings and all aspects of anesthetic management were at the discretion of the anesthesia care team. We defined PLV and non-PLV as <8 or ≥8 mL/kg (predicted body weight) mean tidal volume. The primary outcome was the occurrence of pneumonia and/or acute respiratory distress syndrome (ARDS). Propensity score matching was used to generate PLV and non-PLV groups with comparable characteristics. Associations between outcomes and PLV status were analyzed by exact logistic regression, with matching as cluster in the anatomic and nonanatomic lung resection cohorts. In the propensity score-matched analysis, the incidence of pneumonia and/or ARDS among patients who had an anatomic lung resection was 9/172 (5.2%) in the non-PLV compared to the PLV group 7/172 (4.1%; odds ratio, 1.29; 95% confidence interval, 0.48-3.45, P= .62). The incidence of pneumonia and/or ARDS in patients who underwent nonanatomic resection was 3/118 (2.5%) in the non-PLV compared to the PLV group, 1/118 (0.9%; odds ratio, 3.00; 95% confidence interval, 0.31-28.84, P= .34). In this prospective observational study, we found no differences in the incidence of pneumonia and/or ARDS between patients undergoing lung resection with tidal volumes <8 or ≥8 mL/kg. Our data suggest that when fluid restriction and peak airway pressures are limited, the clinical impact of PLV in this patient population is small. Future randomized trials are needed to better understand the
Mohney, Nathaniel; Williamson, Craig A; Rothman, Edward; Ball, Ron; Sheehan, Kyle M; Pandey, Aditya S; Fletcher, Jeffrey J; Jacobs, Teresa L; Thompson, B Gregory; Rajajee, Venkatakrishna
2018-01-01
An inflammatory response occurs after aneurysmal subarachnoid hemorrhage (aSAH) and predicts poor outcomes. Glucocorticoids suppress inflammation and promote fluid retention. Dexamethasone is often administered after aSAH for postoperative cerebral edema and refractory headache. Our objective was to examine the impact of dexamethasone use on functional outcomes and delayed cerebral ischemia (DCI) after aSAH. Patients with aSAH admitted between 2010 and 2015 were included; the data source was a single-center subarachnoid hemorrhage registry. The intervention of interest was a dexamethasone taper used <7 days from ictus. The primary outcome was poor discharge functional outcome, with a modified Rankin Scale score >3. Other outcomes included DCI and infection. A propensity score for use of dexamethasone was calculated using a logistic regression model that included potential predictors of dexamethasone use and outcome. The impact of dexamethasone on outcomes of interest was calculated and the propensity score was controlled for. A total of 440 patients with subarachnoid hemorrhage were admitted during the study period and 309 met eligibility criteria. Dexamethasone was administered in 101 patients (33%). A total of 127 patients (41%) had a discharge modified Rankin Scale score >3, 105 (34%) developed DCI, and 94 (30%) developed an infection. After propensity score analysis, dexamethasone use was associated with a significant reduction in poor functional outcomes (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.19-0.66) but showed no significant association with DCI (OR, 0.93; 95% CI, 0.53-1.64) or infection (OR, 0.60; 95% CI, 0.34-1.06). Dexamethasone use after aSAH was associated with a reduction in poor functional outcomes at discharge but not DCI, controlling for predictors of dexamethasone use. Copyright © 2017 Elsevier Inc. All rights reserved.
The use of propensity scores to assess the generalizability of results from randomized trials
Stuart, Elizabeth A.; Cole, Stephen R.; Bradshaw, Catherine P.; Leaf, Philip J.
2014-01-01
Randomized trials remain the most accepted design for estimating the effects of interventions, but they do not necessarily answer a question of primary interest: Will the program be effective in a target population in which it may be implemented? In other words, are the results generalizable? There has been very little statistical research on how to assess the generalizability, or “external validity,” of randomized trials. We propose the use of propensity-score-based metrics to quantify the similarity of the participants in a randomized trial and a target population. In this setting the propensity score model predicts participation in the randomized trial, given a set of covariates. The resulting propensity scores are used first to quantify the difference between the trial participants and the target population, and then to match, subclassify, or weight the control group outcomes to the population, assessing how well the propensity score-adjusted outcomes track the outcomes actually observed in the population. These metrics can serve as a first step in assessing the generalizability of results from randomized trials to target populations. This paper lays out these ideas, discusses the assumptions underlying the approach, and illustrates the metrics using data on the evaluation of a schoolwide prevention program called Positive Behavioral Interventions and Supports. PMID:24926156
Retamar, Pilar; Portillo, María M.; López-Prieto, María Dolores; Rodríguez-López, Fernando; de Cueto, Marina; García, María V.; Gómez, María J.; del Arco, Alfonso; Muñoz, Angel; Sánchez-Porto, Antonio; Torres-Tortosa, Manuel; Martín-Aspas, Andrés; Arroyo, Ascensión; García-Figueras, Carolina; Acosta, Federico; Corzo, Juan E.; León-Ruiz, Laura; Escobar-Lara, Trinidad
2012-01-01
The impact of the adequacy of empirical therapy on outcome for patients with bloodstream infections (BSI) is key for determining whether adequate empirical coverage should be prioritized over other, more conservative approaches. Recent systematic reviews outlined the need for new studies in the field, using improved methodologies. We assessed the impact of inadequate empirical treatment on the mortality of patients with BSI in the present-day context, incorporating recent methodological recommendations. A prospective multicenter cohort including all BSI episodes in adult patients was performed in 15 hospitals in Andalucía, Spain, over a 2-month period in 2006 to 2007. The main outcome variables were 14- and 30-day mortality. Adjusted analyses were performed by multivariate analysis and propensity score-based matching. Eight hundred one episodes were included. Inadequate empirical therapy was administered in 199 (24.8%) episodes; mortality at days 14 and 30 was 18.55% and 22.6%, respectively. After controlling for age, Charlson index, Pitt score, neutropenia, source, etiology, and presentation with severe sepsis or shock, inadequate empirical treatment was associated with increased mortality at days 14 and 30 (odds ratios [ORs], 2.12 and 1.56; 95% confidence intervals [95% CI], 1.34 to 3.34 and 1.01 to 2.40, respectively). The adjusted ORs after a propensity score-based matched analysis were 3.03 and 1.70 (95% CI, 1.60 to 5.74 and 0.98 to 2.98, respectively). In conclusion, inadequate empirical therapy is independently associated with increased mortality in patients with BSI. Programs to improve the quality of empirical therapy in patients with suspicion of BSI and optimization of definitive therapy should be implemented. PMID:22005999
An Introduction to Propensity Scores: What, When, and How
ERIC Educational Resources Information Center
Beal, Sarah J.; Kupzyk, Kevin A.
2014-01-01
The use of propensity scores as a method to promote causality in studies that cannot use random assignment has increased dramatically since its original publication in 1983. While the utility of these approaches is important, the concepts underlying their use are complex. The purpose of this article is to provide a basic tutorial for conducting…
The Use of Propensity Scores as a Matching Strategy
ERIC Educational Resources Information Center
John, Lindsay; Wright, Robin; Duku, Eric K.; Willms, J. Douglas
2008-01-01
Objectives: This study reports on the concept and method of linear propensity scores used to obtain a comparison group from the National Longitudinal Survey of Children and Youth to assess the effects of a longitudinal, structured arts program for Canadian youth (aged 9 to 15 years) from low-income, multicultural communities. Method: This study…
Palmer, Joshua D; Schneider, Charles J; Hockstein, Neil; Hanlon, Alexandra L; Silberg, Jordan; Strasser, Jon; Mauer, Elizabeth A; Dzeda, Michael; Witt, Robert; Raben, Adam
2018-03-01
The objective of this study was to investigate the safety, tolerability and preliminary efficacy of radiotherapy plus cetuximab in high risk CSCC patients. Patients with high-risk CSCC diagnosed between 2006 and 2013 were analyzed. Patients were divided into two groups: radiotherapy alone versus radiotherapy plus cetuximab. Among 68 patients meeting study criteria, we identified 29 treated with cetuximab plus RT and 39 with RT alone. Primary analysis examined disease-free and overall survival, freedom from local and distant recurrence in the propensity score matched cohort. Propensity score analysis was performed with weighted factors including: Charlson Comorbidity Index score, age. KPS, primary location, T and N stage, recurrent status, margin status, LVSI, PNI and grade. Toxicity was assessed using the CTCAE v4.0. Median follow-up for living patients was 30 months. Patients in the cetuximab group were more likely to have advanced N stage, positive margins and recurrent disease. After propensity score matching the groups were well balanced. Six patients experienced ≥ grade 3 acute toxicity in the cetuximab group. The 1-year, 2-year and 5-year progression free survival (PFS) for patients in the cetuximab group were 86%, 72% and 66%, respectively. The 1-year, 2-year and 5-year overall survival (OS) for patients in the cetuximab group was 98%, 80% and 80%, respectively. Although limited by small numbers, the combination of cetuximab and radiotherapy in CSCC appears well tolerated there were more long-term survivors and less distant metastasis in the cetuximab group. These promising finding warrant further studies. Copyright © 2018 Elsevier Ltd. All rights reserved.
Kim, Jin Sug; Kim, Weon; Park, Ji Yoon; Woo, Jong Shin; Lee, Tae Won; Ihm, Chun Gyoo; Kim, Yang Gyun; Moon, Ju-Young; Lee, Sang Ho; Jeong, Myung Ho; Jeong, Kyung Hwan
2017-01-01
Lipid lowering therapy is widely used for the prevention of cardiovascular complications after acute myocardial infarction (AMI). However, some studies show that this benefit is uncertain in patients with renal dysfunction, and the role of statins is based on the severity of renal dysfunction. In this study, we investigated the impact of statin therapy on major adverse cardiac events (MACEs) and all-cause mortality in patients with advanced renal dysfunction undergoing percutaneous coronary intervention (PCI) after AMI. This study was based on the Korea Acute Myocardial Infarction Registry database. We included 861 patients with advanced renal dysfunction from among 33,205 patients who underwent PCI after AMI between November 2005 and July 2012. Patients were divided into two groups: a statin group (n = 537) and a no-statin group (n = 324). We investigated the 12-month MACEs (cardiac death, myocardial infarction, repeated PCI or coronary artery bypass grafting) and all-cause mortality of each group. Subsequently, a propensity score-matched analysis was performed. In the total population studied, no significant differences were observed between the two groups with respect to the rate of recurrent MI, repeated PCI, coronary artery bypass grafting (CABG), or all-cause mortality. However, the cardiac death rate was significantly lower in the statin group (p = 0.009). Propensity score-matched analysis yielded 274 pairs demonstrating, results similar to those obtained from the total population. However, there was no significant difference in the cardiac death rate in the propensity score-matched population (p = 0.103). Cox-regression analysis revealed only left ventricular ejection fraction to be an independent predictor of 12-month MACEs (Hazard ratio [HR] of 0.979, 95% confidence interval [CI], 0962-0.996, p = 0.018). Statin therapy was not significantly associated with a reduction in the 12-month MACEs or all-cause mortality in patients with advanced renal dysfunction
Propensity score matching of the gymnastics for diabetes mellitus using logistic regression
NASA Astrophysics Data System (ADS)
Otok, Bambang Widjanarko; Aisyah, Amalia; Purhadi, Andari, Shofi
2017-12-01
Diabetes Mellitus (DM) is a group of metabolic diseases with characteristics shows an abnormal blood glucose level occurring due to pancreatic insulin deficiency, decreased insulin effectiveness or both. The report from the ministry of health shows that DMs prevalence data of East Java province is 2.1%, while the DMs prevalence of Indonesia is only 1,5%. Given the high cases of DM in East Java, it needs the preventive action to control factors causing the complication of DM. This study aims to determine the combination factors causing the complication of DM to reduce the bias by confounding variables using Propensity Score Matching (PSM) with the method of propensity score estimation is binary logistic regression. The data used in this study is the medical record from As-Shafa clinic consisting of 6 covariates and health complication as response variable. The result of PSM analysis showed that there are 22 of 126 DMs patients attending gymnastics paired with patients who didnt attend to diabetes gymnastics. The Average Treatment of Treated (ATT) estimation results showed that the more patients who didnt attend to gymnastics, the more likely the risk for the patients having DMs complications.
Sheu, Tommy; Heymach, John V; Swisher, Stephen G; Rao, Ganesh; Weinberg, Jeffrey S; Mehran, Reza; McAleer, Mary Frances; Liao, Zhongxing; Aloia, Thomas A; Gomez, Daniel R
2014-11-15
To retrospectively analyze factors influencing survival in patients with non-small cell lung cancer presenting with ≤3 synchronous metastatic lesions. We identified 90 patients presenting between 1998 and 2012 with non-small cell lung cancer and ≤3 metastatic lesions who had received at least 2 cycles of chemotherapy followed by surgery or radiation therapy before disease progression. The median number of chemotherapy cycles before comprehensive local therapy (CLT) (including concurrent chemoradiation as first-line therapy) was 6. Factors potentially affecting overall (OS) or progression-free survival (PFS) were evaluated with Cox proportional hazards regression. Propensity score matching was used to assess the efficacy of CLT. Median follow-up time was 46.6 months. Benefits in OS (27.1 vs 13.1 months) and PFS (11.3 months vs 8.0 months) were found with CLT, and the differences were statistically significant when propensity score matching was used (P ≤ .01). On adjusted analysis, CLT had a statistically significant benefit in terms of OS (hazard ratio, 0.37; 95% confidence interval, 0.20-0.70; P ≤ .01) but not PFS (P=.10). In an adjusted subgroup analysis of patients receiving CLT, favorable performance status (hazard ratio, 0.43; 95% confidence interval, 0.22-0.84; P=.01) was found to predict improved OS. Comprehensive local therapy was associated with improved OS in an adjusted analysis and seemed to favorably influence OS and PFS when factors such as N status, number of metastatic lesions, and disease sites were controlled for with propensity score-matched analysis. Patients with favorable performance status had improved outcomes with CLT. Ultimately, prospective, randomized trials are needed to provide definitive evidence as to the optimal treatment approach for this patient population. Copyright © 2014 Elsevier Inc. All rights reserved.
Nirula, Ram; Millar, D; Greene, Tom; McFadden, Molly; Shah, Lubdha; Scalea, Thomas M; Stein, Deborah M; Magnotti, Louis J; Jurkovich, Gregory J; Vercruysse, Gary; Demetriades, Demetrios; Scherer, Lynette A; Peitzman, Andrew; Sperry, Jason; Beauchamp, Kathryn; Bell, Scott; Feiz-Erfan, Iman; O'Neill, Patrick; Coimbra, Raul
2014-04-01
Moderate/severe traumatic brain injury (TBI) management involves minimizing cerebral edema to maintain brain oxygen delivery. While medical therapy (MT) consisting of diuresis, hyperosmolar therapy, ventriculostomy, and barbiturate coma is the standard of care, decompressive craniectomy (DC) for refractory intracranial hypertension (ICH) has gained renewed interest. Since TBI treatment guidelines consider DC a second-tier intervention after MT failure, we sought to determine if early DC (<48 hours) was associated with improved survival in patients with refractory ICH. Eleven Level 1 trauma centers provided clinical data and head computed tomographic scans for patients with a Glasgow Coma Scale (GCS) score of 13 or less and radiographic evidence of TBI excluding deaths within 48 hours. Computed tomographic scans were graded according to the Marshall classification. A propensity score to receive DC (regardless of whether DC was performed) was calculated for each patient based on patient characteristics, physiology, injury severity, GCS, severity of intracranial injury, and treatment center. Patients who actually received a DC were matched to patients with similar propensity scores who received MT for analysis. Outcomes were compared between early (<48 hours of injury) primary or secondary DC and matched controls and then between early primary DC only and matched controls. There were 2,602 patients who met the inclusion criteria ,of whom 264 (10.1%) received DC (either primary or secondary to another cranial procedure) and 109 (5%) had a DC that was primary. Variables associated with performing a DC included sex, race, intracranial pressure monitor placement, in-house trauma attending, traumatic subarachnoid hemorrhage, midline shift, and basal cistern compression. There was no survival benefit with early primary DC compared with the controls (relative risk, 1.07; 95% confidence interval, 0.67-1.73; p = 0.77), and resource use was higher. Early DC does not seem to
Wan, Xin; Xie, Xiangcheng; Gendoo, Yasser; Chen, Xin; Ji, Xiaobing; Cao, Changchun
2016-02-17
Systemic inflammation is involved in the development of acute kidney injury (AKI) after cardiac surgery with cardiopulmonary bypass (CPB). Ulinastatin, a urinary trypsin inhibitor (UTI), possesses a variety of anti-inflammatory effects. Therefore, we hypothesized that the administration of ulinastatin would reduce the occurrence of AKI in patients undergoing cardiac surgery with CPB. A retrospective propensity score matched analysis was used to evaluate the effect of ulinastatin on the development of AKI in patients undergoing first documented cardiac surgery with CPB between January 2008 and December 2012 in our hospital. Multiple logistic regression models were also employed to identify the association between UTI administration and development of AKI. A total of 2072 patients who underwent cardiac surgery with CPB met the inclusion criteria. Before propensity score matching, variables such as age, baseline creatinine, CPB duration, red blood cells transfused, and hematocrit were statistically different between the ulinastatin (UTI) group and the control group. On the basis of propensity scores, 409 UTI patients were successfully matched to the 409 patients from among those 1663 patients without UTI administration. After propensity score matching, no statistically significant differences in the baseline characteristics were found between the UTI group and the control group. The propensity score matched cohort analysis revealed that AKI and the need for renal replacement therapy occurred more frequently in the control group than in the UTI group (40.83% vs. 30.32%, P = 0.002; 2.44% vs. 0.49%, P = 0.02, respectively). However, there were no significant differences in mortality, length of intensive care unit stay, and length of hospital stay between the UTI group and the control group. Using multivariate logistic regression analysis, we found ulinastatin played a protective role in the development of AKI after cardiac surgery (odds ratio 0.71, 95% confidence
Andersen, Lars W; Kurth, Tobias; Chase, Maureen; Berg, Katherine M; Cocchi, Michael N; Callaway, Clifton; Donnino, Michael W
2016-04-06
To evaluate whether patients who experience cardiac arrest in hospital receive epinephrine (adrenaline) within the two minutes after the first defibrillation (contrary to American Heart Association guidelines) and to evaluate the association between early administration of epinephrine and outcomes in this population. Prospective observational cohort study. Analysis of data from the Get With The Guidelines-Resuscitation registry, which includes data from more than 300 hospitals in the United States. Adults in hospital who experienced cardiac arrest with an initial shockable rhythm, including patients who had a first defibrillation within two minutes of the cardiac arrest and who remained in a shockable rhythm after defibrillation. Epinephrine given within two minutes after the first defibrillation. Survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and survival to hospital discharge with a good functional outcome. A propensity score was calculated for the receipt of epinephrine within two minutes after the first defibrillation, based on multiple characteristics of patients, events, and hospitals. Patients who received epinephrine at either zero, one, or two minutes after the first defibrillation were then matched on the propensity score with patients who were "at risk" of receiving epinephrine within the same minute but who did not receive it. 2978 patients were matched on the propensity score, and the groups were well balanced. 1510 (51%) patients received epinephrine within two minutes after the first defibrillation, which is contrary to current American Heart Association guidelines. Epinephrine given within the first two minutes after the first defibrillation was associated with decreased odds of survival in the propensity score matched analysis (odds ratio 0.70, 95% confidence interval 0.59 to 0.82; P<0.001). Early epinephrine administration was also associated with a decreased odds of return of spontaneous circulation
Nissen, Jette Lindbjerg; Skov, Robert; Knudsen, Jenny Dahl; Ostergaard, Christian; Schønheyder, Henrik Carl; Frimodt-Møller, Niels; Benfield, Thomas
2013-08-01
Penicillin-susceptible Staphylococcus aureus isolates account for a fifth of cases of S. aureus bacteraemia (SAB) in Denmark, but little is known about treatment outcomes with penicillins or other antimicrobials. Here we compare penicillin, dicloxacillin and cefuroxime as definitive treatments in relation to 30 day mortality. A retrospective chart review of 588 penicillin-susceptible S. aureus cases at five centres from January 1995 to December 2010. Data on demographics, antimicrobial treatment, clinical signs and symptoms, and mortality at day 30 were collected. Hazard ratios (HRs) with 95% CIs associated with mortality were modelled using propensity-score-adjusted Cox proportional hazards regression analysis. Propensity-score-matched case-control studies were carried out. Definitive therapy with cefuroxime was associated with an increased risk of 30 day mortality compared with penicillin (adjusted HR 2.54, 95% CI 1.49-4.32). Other variables that were statistically significantly associated with 30 day mortality included increasing age, disease severity and a primary respiratory focus. Osteomyelitis/arthritis was associated with a lower risk of death than were other secondary manifestations. Propensity-score-matched case-control studies confirmed an increased risk of 30 day mortality: cefuroxime treatment (39%) versus penicillin treatment (20%), P = 0.037; and cefuroxime treatment (38%) versus dicloxacillin treatment (10%), P = 0.004. Definitive therapy for penicillin-susceptible SAB with cefuroxime was associated with a significantly higher mortality than was seen with therapy with penicillin or dicloxacillin.
Werth, Jilynn M; Nickerson, Amanda B; Aloe, Ariel M; Swearer, Susan M
2015-08-01
This study investigated how bystanders, who have and have not been bullied, perceive their social and emotional maladjustment depending on the form of bullying (physical or verbal) they witness. Using propensity score matching, equivalent groups of 270 victimized and 270 non-victimized bystander groups were created based on middle school students' responses on the Bully Survey-Student Version (BYS-S; Swearer, 2001). Victimized bystanders experienced higher social maladjustment than non-victimized bystanders. Path analysis results suggest that social and emotional maladjustment as a bystander is related not only to social-emotional maladjustment as victim, but to gender and the form of bullying witnessed. The way in which bystanders are influenced by their personal victimization may be a critical factor in predicting, understanding, and increasing active bystander intervention. Copyright © 2015 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.
Role of breastfeeding in childhood cognitive development: a propensity score matching analysis.
Boutwell, Brian B; Beaver, Kevin M; Barnes, James C
2012-09-01
To examine whether the association between breastfeeding and childhood cognitive development is direct or whether the association is spurious owing to confounding variables. The current study conducted a propensity score matching (PSM) analysis using data from the Early Childhood Longitudinal Study, Birth Cohort. The results of PSM models revealed that prior to matching, the association between breastfeeding and cognitive functioning was significant (mean difference = 3.20, t-value = 7.86, 95% confidence interval (CI) = 2.40-4.00, P ≤ 0.05). After controlling for a range of confounding factors, the mean difference was reduced by 40% (mean difference = 1.92, t-value = 3.75, 95% CI = 0.92-2.93, P ≤ 0.05); however, significant differences remained between groups. The results produced in the current study provide tentative evidence that breastfeeding may have an influence on the development of cognitive abilities in children. Additional research is necessary, however, in order to further evaluate the causal impact and exact developmental pathway of breastfeeding on childhood cognitive growth. © 2012 The Authors. Journal of Paediatrics and Child Health © 2012 Paediatrics and Child Health Division (Royal Australasian College of Physicians).
Iwata, Hisashi; Shirahashi, Koyo; Yamamoto, Hirotaka; Marui, Tsutomu; Matsumoto, Shinsuke; Mizuno, Yoshimasa; Matsumoto, Mitsuyoshi; Mitta, Shohei; Miyamoto, Yusaku; Komuro, Hiroyasu
2016-04-01
Video-assisted thoracoscopic surgery (VATS) lobectomy is classified into hybrid VATS (direct and video vision) and thoracoscopic VATS (video vision only). In this study, the outcomes of hybrid VATS and thoracoscopic VATS for clinical stage I lung cancer were compared using a propensity score-matching analysis. Hybrid and thoracoscopic VATS were performed in 178 and 76 patients, respectively. Propensity scores were calculated using logistic regression analysis and matched within a score of ±0.03 for age, sex, size of tumour, Charlson comorbidity index, preoperative therapy, percent vital capacity, forced expiratory volume in 1 s, clinical stage, pathological stage and histology. In the non-matched analysis, the results for hybrid and thoracoscopic VATS, respectively, were as follows: mean age, 69 ± 9 and 66 ± 10 years (P = 0.04); tumour size, 24 ± 10 and 20 ± 7 mm (P < 0.01); 2-deoxy-2 [F-18]fluorodeoxyglucose positron emission tomography SUV, 5.6 ± 4.4 and 3.6 ± 3.2 (P < 0.01); clinical stage (IA/IB), 130/48 and 69/7 (P < 0.01); pathological stage (IA/IB/IIA and IIB/IIIA and IIIB), 89/56/15/18 and 57/14/2/3 (P < 0.01); postoperative complications, 66 (37.1%) and 16 (21.1%; P = 0.01); respiratory complications, 32 (18.0%) and 6 (7.9%; P = 0.04); 5-year overall survival (OS), 77.0 and 88.8% (log-rank P = 0.045); and 5-year disease-free survival (DFS), 67.2 and 81.1% (log-rank P = 0.02). In 66 matched cases, the results for hybrid and thoracoscopic VATS, respectively, were as follows: mean operative time, 245 ± 96 and 285 ± 85 min (P = 0.01); blood loss, 95 ± 100 and 86 ± 123 ml (P = 0.67); mean duration of drainage, 3.6 ± 2.7 and 3.2 ± 2.2 days (P = 0.37); postoperative complications, 21 (31.8%) and 14 (21.2%; P = 0.17); respiratory complications, 11 (16.7%) and 5 (7.6%; P = 0.11); 5-year OS, 72.5 and 86.0% (log-rank P = 0.25); and 5-year DFS, 68.4 and 77.2% (log-rank P = 0.17). In this single-institution, propensity score-matched study, hybrid VATS
Thoracic irrigation prevents retained hemothorax: A prospective propensity scored analysis.
Kugler, Nathan W; Carver, Thomas W; Milia, David; Paul, Jasmeet S
2017-12-01
Thoracic trauma resulting in hemothorax (HTx) is typically managed with thoracostomy tube (TT) placement; however, up to 20% of patients develop retained HTx which may necessitate further intervention for definitive management. Although optimal management of retained HTx has been extensively researched, little is known about prevention of this complication. We hypothesized that thoracic irrigation at the time of TT placement would significantly decrease the rate of retained HTx necessitating secondary intervention. A prospective, comparative study of patients with traumatic HTx who underwent bedside TT placement was conducted. The control group consisted of patients who underwent standard TT placement, whereas the irrigation group underwent standard TT placement with immediate irrigation using 1 L of warmed sterile 0.9% saline. Patients who underwent emergency thoracotomy, those with TTs removed within 24 hours, or those who died within 30 days of discharge were excluded. The primary end point was secondary intervention defined by additional TT placement or operative management for retained HTx. A propensity-matched analysis was performed with scores estimated using a logistic regression model based on age, sex, mechanism of injury, Abbreviated Injury Scale chest score, and TT size. In over a 30-month period, a total of 296 patients underwent TT placement for the management of traumatic HTx. Patients were predominantly male (79.6%) at a median age of 40 years and were evenly split between blunt (48.8%) and penetrating (51.2%) mechanisms. Sixty (20%) patients underwent thoracic irrigation at time of initial TT placement. The secondary intervention rate was significantly lower within the study group (5.6% vs. 21.8%; OR, 0.16; p < 0.001). No significant differences in TT duration, ventilator days, or length of stay were noted between the irrigation and control cohort. Thoracic irrigation at the time of initial TT placement for traumatic HTx significantly reduced the
Mericli, Alexander F; Garvey, Patrick B; Giordano, Salvatore; Liu, Jun; Baumann, Donald P; Butler, Charles E
2017-03-01
The optimal strategy for abdominal wall reconstruction in the presence of a stomal-site hernia is unclear. We hypothesized that the rate of ventral hernia recurrence in patients undergoing a combined ventral hernia repair and stomal-site herniorraphy would not differ clinically from the ventral hernia recurrence rate in patients undergoing an isolated ventral hernia repair. We also hypothesized that bridged ventral hernia repairs result in worse outcomes compared with reinforced repairs, regardless of stomal hernia. We retrospectively reviewed prospectively collected data from consecutive abdominal wall reconstructions performed with acellular dermal matrix (ADM) at a single center between 2000 and 2015. We compared patients who underwent a ventral hernia repair alone (AWR) and those who underwent both a ventral hernia repair and ostomy-associated herniorraphy (AWR+O). We conducted a propensity score matched analysis to compare the outcomes between the 2 groups. Multivariable Cox proportional hazards and logistic regression models were used to study associations between potential predictive or protective reconstructive strategies and surgical outcomes. We included 499 patients (median follow-up 27.2 months; interquartile range [IQR] 12.4 to 46.6 months), 118 AWR+O and 381 AWR. After propensity score matching, 91 pairs were obtained. Ventral hernia recurrence was not statistically associated with ostomy-associated herniorraphy (adjusted hazard ratio [HR] 0.7; 95% CI 0.3 to 1.5; p = 0.34). However, the AWR+O group experienced a significantly higher percentage of surgical site occurrences (34.1%) than the AWR group (18.7%; adjusted odds ratio 2.3; 95% CI 1.4 to 3.7; p < 0.001). In the AWR group, there were significantly fewer ventral hernia recurrences when the repair was reinforced compared with bridged (5.3% vs 38.5%; p < 0.001). There was no statistically significant difference in ventral hernia recurrence between the AWR and AWR+O groups. Bridging was associated
Ecochard-Dugelay, Emmanuelle; Beliah, Muriel; Boisson, Caroline; Perreaux, Francis; de Laveaucoupet, Jocelyne; Labrune, Philippe; Epaud, Ralph; Ducou-Lepointe, Hubert; Bouyer, Jean; Gajdos, Vincent
2014-01-01
Management of acute respiratory tract infection varies substantially despite this being a condition frequently encountered in pediatric emergency departments. Previous studies have suggested that the use of antibiotics was higher when chest radiography was performed. However none of these analyses had considered the inherent indication bias of observational studies. The aim of this work was to assess the relationship between performing chest radiography and prescribing antibiotics using a propensity score analysis to address the indication bias due to non-random radiography assignment. We conducted a prospective study of 697 children younger than 2 years of age who presented during the winter months of 2006-2007 for suspicion of respiratory tract infection at the Pediatric Emergency Department of an urban general hospital in France (Paris suburb). We first determined the individual propensity score (probability of having a chest radiography according to baseline characteristics). Then we assessed the relation between radiography and antibiotic prescription using two methods: adjustment and matching on the propensity score. We found that performing a chest radiography lead to more frequent antibiotic prescription that may be expressed as OR = 2.3, CI [1.3-4.1], or as an increased use of antibiotics of 18.6% [0.08-0.29] in the group undergoing chest radiography. Chest radiography has a significant impact on the management of infants admitted for suspicion of respiratory tract infection in a pediatric emergency department and may lead to unnecessary administration of antibiotics.
De Angelis, Carmine; Di Maio, Massimo; Crispo, Anna; Giuliano, Mario; Schettini, Francesco; Bonotto, Marta; Gerratana, Lorenzo; Iacono, Donatella; Cinausero, Marika; Riccardi, Ferdinando; Ciancia, Giuseppe; De Laurentiis, Michelino; Puglisi, Fabio; De Placido, Sabino; Arpino, Grazia
2017-01-01
The benefit of adding chemotherapy (CT) to adjuvant hormone therapy (HT) in stage IA luminal-like HER2-negative breast cancer (BC) is unclear. We retrospectively evaluated predictive factors and clinical outcome of 1,222 patients from 4 oncologic centers. Three hundred and eighty patients received CT and HT (CT-cohort) and 842 received HT alone (HT-cohort). Disease-free survival (DFS) and overall survival (OS) were evaluated with univariate and multivariate analyses. We also applied the propensity score methodology. Compared with the HT-cohort, patients in the CT-cohort were more likely to be younger, have larger tumors of a higher histological grade that were Ki67-positive, and lower estrogen and progesterone receptor expression. At univariate analysis, a higher histological grade and Ki67 were significantly associated to a lower DFS. At multivariable analysis, only histological grade was predictive of DFS. The CT-cohort had a worse outcome than the HT-cohort in terms of DFS and OS, but differences disappeared when matched according to propensity score. In summary, patients with stage IA luminal-like BC had an excellent prognosis, however relapse and mortality were higher in the CT-cohort than in the HT-cohort. Longer use of adjuvant HT or other therapeutic strategies may be needed to improve outcome. PMID:29348868
A Propensity Score Matching Analysis of the Effects of Special Education Services.
Morgan, Paul L; Frisco, Michelle; Farkas, George; Hibel, Jacob
2010-02-01
We sought to quantify the effectiveness of special education services as naturally delivered in U.S. schools. Specifically, we examined whether children receiving special education services displayed (a) greater reading or mathematics skills, (b) more frequent learning-related behaviors, or (c) less frequent externalizing or internalizing problem behaviors than closely matched peers not receiving such services. To do so, we used propensity score matching techniques to analyze data from the Early Childhood Longitudinal-Study Kindergarten Cohort, 1998-1999, a large scale, nationally representative sample of U.S. schoolchildren. Collectively, results indicate that receipt of special education services has either a negative or statistically non-significant impact on children's learning or behavior. However, special education services do yield a small, positive effect on children's learning-related behaviors.
Suh, Chong Hyun; Choi, Young Jun; Lee, Jong Jin; Shim, Woo Hyun; Baek, Jung Hwan; Chung, Han Cheol; Shong, Young Kee; Song, Dong Eun; Sung, Tae Yon; Lee, Jeong Hyun
2017-10-01
This study used a propensity score analysis to assess the roles of core-needle biopsy (CNB) and fine-needle aspiration (FNA) in the evaluation of thyroid incidentalomas detected on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT). The study population was obtained from a historical cohort who underwent 18 F-FDG PET/CT between October 2008 and September 2015. Patients were included who underwent ultrasound-guided CNB or FNA for incidental focal uptake of 18 F-FDG in the thyroid gland on PET/CT. The primary study outcomes included the inconclusive result rates in the CNB and FNA groups. The secondary outcome measures included the non-diagnostic result rate and the diagnostic performance for neoplasms. Multivariate analysis, propensity score matching, and inverse probability weighting were conducted. A total of 1360 nodules from 1338 patients were included in this study: 859 nodules from 850 patients underwent FNA, and 501 nodules from 488 patients underwent CNB. Compared to FNA, CNB demonstrated a significantly lower inconclusive result rate in the pooled cohort (23.8% vs. 35.4%; p < 0.001), propensity score-matched cohorts (22.9% vs. 36.6%; p < 0.001), and with inverse probability weighting (22.4% vs. 35.2%; p < 0.001). Non-diagnostic result rates were also significantly lower in CNB than in FNA. The diagnostic performance of the two groups in the pooled and matched cohorts was similar, with no significant differences found. The significantly lower inconclusive result rates in CNB than in FNA were consistent within the propensity score-matched cohorts. Therefore, CNB appears to be a promising diagnostic tool for patients with thyroid incidentalomas detected on 18 F-FDG PET/CT.
Tein, Jenn-Yun; Mazza, Gina L; Gunn, Heather J; Kim, Hanjoe; Stuart, Elizabeth A; Sandler, Irwin N; Wolchik, Sharlene A
2018-06-01
We used a multigroup propensity score approach to evaluate a randomized effectiveness trial of the New Beginnings Program (NBP), an intervention targeting divorced or separated families. Two features of effectiveness trials, high nonattendance rates and inclusion of an active control, make program effects harder to detect. To estimate program effects based on actual intervention participation, we created a synthetic inactive control comprised of nonattenders and assessed the impact of attending the NBP or active control relative to no intervention (inactive control). We estimated propensity scores using generalized boosted models and applied inverse probability of treatment weighting for the comparisons. Relative to the inactive control, NBP strengthened parenting quality as well as reduced child exposure to interparental conflict, parent psychological distress, and child internalizing problems. Some effects were moderated by parent gender, parent ethnicity, or child age. On the other hand, the effects of active versus inactive control were minimal for parenting and in the unexpected direction for child internalizing problems. Findings from the propensity score approach complement and enhance the interpretation of findings from the intention-to-treat approach.
Senn, Stephen; Graf, Erika; Caputo, Angelika
2007-12-30
Stratifying and matching by the propensity score are increasingly popular approaches to deal with confounding in medical studies investigating effects of a treatment or exposure. A more traditional alternative technique is the direct adjustment for confounding in regression models. This paper discusses fundamental differences between the two approaches, with a focus on linear regression and propensity score stratification, and identifies points to be considered for an adequate comparison. The treatment estimators are examined for unbiasedness and efficiency. This is illustrated in an application to real data and supplemented by an investigation on properties of the estimators for a range of underlying linear models. We demonstrate that in specific circumstances the propensity score estimator is identical to the effect estimated from a full linear model, even if it is built on coarser covariate strata than the linear model. As a consequence the coarsening property of the propensity score-adjustment for a one-dimensional confounder instead of a high-dimensional covariate-may be viewed as a way to implement a pre-specified, richly parametrized linear model. We conclude that the propensity score estimator inherits the potential for overfitting and that care should be taken to restrict covariates to those relevant for outcome. Copyright (c) 2007 John Wiley & Sons, Ltd.
Using Propensity Scores to Reduce Selection Bias in Mathematics Education Research
ERIC Educational Resources Information Center
Graham, Suzanne E.
2010-01-01
Selection bias is a problem for mathematics education researchers interested in using observational rather than experimental data to make causal inferences about the effects of different instructional methods in mathematics on student outcomes. Propensity score methods represent 1 approach to dealing with such selection bias. This article…
Fernández-Ruiz, Mario; Aguado, José María; Almirante, Benito; Lora-Pablos, David; Padilla, Belén; Puig-Asensio, Mireia; Montejo, Miguel; García-Rodríguez, Julio; Pemán, Javier; Ruiz Pérez de Pipaón, Maite; Cuenca-Estrella, Manuel
2014-05-01
Concerns have arisen regarding the optimal antifungal regimen for Candida parapsilosis bloodstream infection (BSI) in view of its reduced susceptibility to echinocandins. The Prospective Population Study on Candidemia in Spain (CANDIPOP) is a prospective multicenter, population-based surveillance program on Candida BSI conducted through a 12-month period in 29 Spanish hospitals. Clinical isolates were identified by DNA sequencing, and antifungal susceptibility testing was performed by the European Committee on Antimicrobial Susceptibility Testing methodology. Predictors for clinical failure (all-cause mortality between days 3 to 30, or persistent candidemia for ≥72 hours after initiation of therapy) in episodes of C. parapsilosis species complex BSI were assessed by logistic regression analysis. We further analyzed the impact of echinocandin-based regimen as the initial antifungal therapy (within the first 72 hours) by using a propensity score approach. Among 752 episodes of Candida BSI identified, 200 (26.6%) were due to C. parapsilosis species complex. We finally analyzed 194 episodes occurring in 190 patients. Clinical failure occurred in 58 of 177 (32.8%) of evaluable episodes. Orotracheal intubation (adjusted odds ratio [AOR], 2.81; P = .018) and septic shock (AOR, 2.91; P = .081) emerged as risk factors for clinical failure, whereas early central venous catheter removal was protective (AOR, 0.43; P = .040). Neither univariate nor multivariate analysis revealed that the initial use of an echinocandin-based regimen had any impact on the risk of clinical failure. Incorporation of the propensity score into the model did not change this finding. The initial use of an echinocandin-based regimen does not seem to negatively influence outcome in C. parapsilosis BSI.
A Propensity Score Matching Analysis of the Effects of Special Education Services
Morgan, Paul L.; Frisco, Michelle; Farkas, George; Hibel, Jacob
2013-01-01
We sought to quantify the effectiveness of special education services as naturally delivered in U.S. schools. Specifically, we examined whether children receiving special education services displayed (a) greater reading or mathematics skills, (b) more frequent learning-related behaviors, or (c) less frequent externalizing or internalizing problem behaviors than closely matched peers not receiving such services. To do so, we used propensity score matching techniques to analyze data from the Early Childhood Longitudinal—Study Kindergarten Cohort, 1998–1999, a large scale, nationally representative sample of U.S. schoolchildren. Collectively, results indicate that receipt of special education services has either a negative or statistically non-significant impact on children’s learning or behavior. However, special education services do yield a small, positive effect on children’s learning-related behaviors. PMID:23606759
A comparison of 12 algorithms for matching on the propensity score.
Austin, Peter C
2014-03-15
Propensity-score matching is increasingly being used to reduce the confounding that can occur in observational studies examining the effects of treatments or interventions on outcomes. We used Monte Carlo simulations to examine the following algorithms for forming matched pairs of treated and untreated subjects: optimal matching, greedy nearest neighbor matching without replacement, and greedy nearest neighbor matching without replacement within specified caliper widths. For each of the latter two algorithms, we examined four different sub-algorithms defined by the order in which treated subjects were selected for matching to an untreated subject: lowest to highest propensity score, highest to lowest propensity score, best match first, and random order. We also examined matching with replacement. We found that (i) nearest neighbor matching induced the same balance in baseline covariates as did optimal matching; (ii) when at least some of the covariates were continuous, caliper matching tended to induce balance on baseline covariates that was at least as good as the other algorithms; (iii) caliper matching tended to result in estimates of treatment effect with less bias compared with optimal and nearest neighbor matching; (iv) optimal and nearest neighbor matching resulted in estimates of treatment effect with negligibly less variability than did caliper matching; (v) caliper matching had amongst the best performance when assessed using mean squared error; (vi) the order in which treated subjects were selected for matching had at most a modest effect on estimation; and (vii) matching with replacement did not have superior performance compared with caliper matching without replacement. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.
A comparison of 12 algorithms for matching on the propensity score
Austin, Peter C
2014-01-01
Propensity-score matching is increasingly being used to reduce the confounding that can occur in observational studies examining the effects of treatments or interventions on outcomes. We used Monte Carlo simulations to examine the following algorithms for forming matched pairs of treated and untreated subjects: optimal matching, greedy nearest neighbor matching without replacement, and greedy nearest neighbor matching without replacement within specified caliper widths. For each of the latter two algorithms, we examined four different sub-algorithms defined by the order in which treated subjects were selected for matching to an untreated subject: lowest to highest propensity score, highest to lowest propensity score, best match first, and random order. We also examined matching with replacement. We found that (i) nearest neighbor matching induced the same balance in baseline covariates as did optimal matching; (ii) when at least some of the covariates were continuous, caliper matching tended to induce balance on baseline covariates that was at least as good as the other algorithms; (iii) caliper matching tended to result in estimates of treatment effect with less bias compared with optimal and nearest neighbor matching; (iv) optimal and nearest neighbor matching resulted in estimates of treatment effect with negligibly less variability than did caliper matching; (v) caliper matching had amongst the best performance when assessed using mean squared error; (vi) the order in which treated subjects were selected for matching had at most a modest effect on estimation; and (vii) matching with replacement did not have superior performance compared with caliper matching without replacement. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd. PMID:24123228
Fallah, Aria; Weil, Alexander G; Juraschka, Kyle; Ibrahim, George M; Wang, Anthony C; Crevier, Louis; Tseng, Chi-Hong; Kulkarni, Abhaya V; Ragheb, John; Bhatia, Sanjiv
2017-12-01
OBJECTIVE Combined endoscopic third ventriculostomy (ETC) and choroid plexus cauterization (CPC)-ETV/CPC- is being investigated to increase the rate of shunt independence in infants with hydrocephalus. The degree of CPC necessary to achieve improved rates of shunt independence is currently unknown. METHODS Using data from a single-center, retrospective, observational cohort study involving patients who underwent ETV/CPC for treatment of infantile hydrocephalus, comparative statistical analyses were performed to detect a difference in need for subsequent CSF diversion procedure in patients undergoing partial CPC (describes unilateral CPC or bilateral CPC that only extended from the foramen of Monro [FM] to the atrium on one side) or subtotal CPC (describes CPC extending from the FM to the posterior temporal horn bilaterally) using a rigid neuroendoscope. Propensity scores for extent of CPC were calculated using age and etiology. Propensity scores were used to perform 1) case-matching comparisons and 2) Cox multivariable regression, adjusting for propensity score in the unmatched cohort. Cox multivariable regression adjusting for age and etiology, but not propensity score was also performed as a third statistical technique. RESULTS Eighty-four patients who underwent ETV/CPC had sufficient data to be included in the analysis. Subtotal CPC was performed in 58 patients (69%) and partial CPC in 26 (31%). The ETV/CPC success rates at 6 and 12 months, respectively, were 49% and 41% for patients undergoing subtotal CPC and 35% and 31% for those undergoing partial CPC. Cox multivariate regression in a 48-patient cohort case-matched by propensity score demonstrated no added effect of increased extent of CPC on ETV/CPC survival (HR 0.868, 95% CI 0.422-1.789, p = 0.702). Cox multivariate regression including all patients, with adjustment for propensity score, demonstrated no effect of extent of CPC on ETV/CPC survival (HR 0.845, 95% CI 0.462-1.548, p = 0.586). Cox multivariate
Shimizu, Fumitaka; Muto, Satoru; Taguri, Masataka; Ieda, Takeshi; Tsujimura, Akira; Sakamoto, Yoshiro; Fujita, Kazuhiko; Okegawa, Takatsugu; Yamaguchi, Raizo; Horie, Shigeo
2017-05-01
To evaluate the clinical benefit of adjuvant platinum-based chemotherapy after radical cystectomy for muscle-invasive bladder cancer in routine clinical practice. The present observational study was carried out to compare the effectiveness of adjuvant chemotherapy versus observation post-radical cystectomy in patients with clinically muscle-invasive bladder cancer. Cancer-specific survival and overall survival between the adjuvant chemotherapy group and radical cystectomy alone group were compared using Kaplan-Meier method and log-rank test. After adjusting for background factors using propensity score weighting, differences in cancer-specific survival and overall survival between these two groups were compared. Subgroup analyses by the pathological characteristics were carried out. In total, 322 patients were included in the present study. Of these, 23% received adjuvant chemotherapy post-radical cystectomy. Clinicopathological characteristics showed that patients in the adjuvant chemotherapy group were pathologically more advanced and were at higher risk than the radical cystectomy alone group. In the unadjusted population, although it is not significant, the adjuvant chemotherapy group had lower overall survival (3-year overall survival; 61.5% vs 73.6%, HR 1.33, P = 0.243, log-rank test, adjuvant chemotherapy vs radical cystectomy alone). In the weighted propensity score analysis, although it is not significant, the adjuvant chemotherapy group were superior to radical cystectomy alone groups (overall survival: HR 0.65, 95% CI 0.39-1.09, P = 0.099, log-rank test, adjuvant chemotherapy vs radical cystectomy alone). Subgroup analyses showed that adjuvant chemotherapy significantly reduced the hazard ratio of overall survival and cancer-specific survival in the ≥pT3, pN+, ly+ and v+ subgroups. Platinum-based adjuvant chemotherapy might be associated with increased cancer-specific survival and overall survival in patients with high-risk invasive bladder cancer.
2013-01-01
Background The impact of minimized extracorporeal circulation (MECC) for emergency revascularization remains controversial. Methods A total of 348 patients underwent emergency CABG with MECC (n=146) or conventional extracorporeal circulation (CECC; n=175) between January 2005 and December 2010. Using propensity score matching after binary logistic regression, 100 patients, who underwent CABG with MECC could be matched with 100 patients, who underwent CABG with CECC. Primary outcome was 30-day mortality. Results Unadjusted 30-day mortality was 14.8% in patients with CECC and 6.9% in those with MECC (mean difference −7.9%; p=0.03). The adjusted mean difference (average treatment effect of the treated, ATT) after matching was −1.0% (95% CI −8.6 to 7.6; p=1.0). Intensive care unit stay (adjusted mean difference 1.0; 95% CI −0.2 to 3.2; p=0.70) and hospital stay (adjusted mean difference 1.0; 95% CI −2.0 to 3.6; p=0.40) did not show significant differences between both groups. The adjusted mean difference for postoperative low cardiac output syndrome was −1.1% (95% CI −7.3 to 7.1; p=0.83) without significant differences between CECC and MECC. Postoperative mechanical ventilation time, drain loss, postoperative rethoracotomy, postoperative neurological events, new onset renal replacement therapy and respiratory failure also had insignificant average treatment effects of the treated. In addition, all average treatment effects (ATEs) did not significantly differ between both groups. Conclusion Using propensity score estimation and matching, we did not observe significant differences in terms of survival and further outcomes in patients who undergo emergency CABG with CECC or MECC, but our results call for further analysis. PMID:23547910
Adragão, Pedro Pulido; Cavaco, Diogo; Ferreira, António Miguel; Costa, Francisco Moscoso; Parreira, Leonor; Carmo, Pedro; Morgado, Francisco Bello; Santos, Katya Reis; Santos, Pedro Galvão; Carvalho, Maria Salomé; Durazzo, Anai; Marques, Hugo; Gonçalves, Pedro Araújo; Raposo, Luís; Mendes, Miguel
2016-03-01
Whether or not the potential advantages of using a magnetic navigation system (MNS) translate into improved outcomes in patients undergoing atrial fibrillation (AF) ablation is a question that remains unanswered. In this observational registry study, we used propensity-score matching to compare the outcomes of patients with symptomatic drug-refractory AF who underwent catheter ablation using MNS with the outcomes of those who underwent catheter ablation using conventional manual navigation. Among 1,035 eligible patients, 287 patients in each group had similar propensity scores and were included in the analysis. The primary efficacy outcome was the rate of AF relapse after a 3-month blanking period. At a mean follow-up of 2.6 ± 1.5 years, AF ablation with MNS was associated with a similar risk of AF relapse as compared with manual navigation (18.4% per year and 22.3% per year, respectively; hazard ratio 0.81, 95% CI 0.63-1.05; P = 0.108). Major complications occurred in two patients (0.7%) using MNS, and in six patients (2.1%) undergoing manually navigated ablation (P = 0.286). Fluoroscopy times were 21 ± 10 minutes in the manual navigation group, and 12 ± 9 minutes in the MNS group (P < 0.001), whereas total procedure times were 152 ± 52 minutes and 213 ± 58 minutes, respectively (P < 0.001). In this propensity-score matched comparison, magnetic navigation and conventional manual AF ablations seem to have similar relapse rates and a similar risk of complications. AF ablations with magnetic navigation take longer to perform but expose patients to significantly shorter fluoroscopy times. © 2015 Wiley Periodicals, Inc.
Using Propensity Score Matching to Test the Community College Penalty Assumption
ERIC Educational Resources Information Center
Dietrich, Cecile C.; Lichtenberger, Eric J.
2015-01-01
Research studies have been ambivalent about whether enrolling in community college makes completing a bachelor's degree less likely than directly enrolling in a four-year institution. This study uses propensity score matching with a posttreatment adjustment to determine the treatment effect associated with taking the community college to four-year…
Understanding Foster Youth Outcomes: Is Propensity Scoring Better than Traditional Methods?
ERIC Educational Resources Information Center
Berzin, Stephanie Cosner
2010-01-01
Objectives: This study seeks to examine the relationship between foster care and outcomes using multiple comparison methods to account for factors that put foster youth at risk independent of care. Methods: Using the National Longitudinal Survey of Youth 1997, matching, propensity scoring, and comparisons to the general population are used to…
Stuart, Elizabeth A.; Huskamp, Haiden A.; Duckworth, Kenneth; Simmons, Jeffrey; Song, Zirui; Chernew, Michael; Barry, Colleen L.
2014-01-01
Difference-in-difference (DD) methods are a common strategy for evaluating the effects of policies or programs that are instituted at a particular point in time, such as the implementation of a new law. The DD method compares changes over time in a group unaffected by the policy intervention to the changes over time in a group affected by the policy intervention, and attributes the “difference-in-differences” to the effect of the policy. DD methods provide unbiased effect estimates if the trend over time would have been the same between the intervention and comparison groups in the absence of the intervention. However, a concern with DD models is that the program and intervention groups may differ in ways that would affect their trends over time, or their compositions may change over time. Propensity score methods are commonly used to handle this type of confounding in other non-experimental studies, but the particular considerations when using them in the context of a DD model have not been well investigated. In this paper, we describe the use of propensity scores in conjunction with DD models, in particular investigating a propensity score weighting strategy that weights the four groups (defined by time and intervention status) to be balanced on a set of characteristics. We discuss the conceptual issues associated with this approach, including the need for caution when selecting variables to include in the propensity score model, particularly given the multiple time point nature of the analysis. We illustrate the ideas and method with an application estimating the effects of a new payment and delivery system innovation (an accountable care organization model called the “Alternative Quality Contract” (AQC) implemented by Blue Cross Blue Shield of Massachusetts) on health plan enrollee out-of-pocket mental health service expenditures. We find no evidence that the AQC affected out-of-pocket mental health service expenditures of enrollees. PMID:25530705
Frenette, Anne Julie; Bouchard, Josée; Bernier, Pascaline; Charbonneau, Annie; Nguyen, Long Thanh; Rioux, Jean-Philippe; Troyanov, Stéphan; Williamson, David R
2014-11-14
The risk of acute kidney injury (AKI) with the use of albumin-containing fluids compared to starches in the surgical intensive care setting remains uncertain. We evaluated the adjusted risk of AKI associated with colloids following cardiac surgery. We performed a retrospective cohort study of patients undergoing on-pump cardiac surgery in a tertiary care center from 2008 to 2010. We assessed crystalloid and colloid administration until 36 hours after surgery. AKI was defined by the RIFLE (risk, injury, failure, loss and end-stage kidney disease) risk and Acute Kidney Injury Network (AKIN) stage 1 serum creatinine criterion within 96 hours after surgery. Our cohort included 984 patients with a baseline glomerular filtration rate of 72 ± 19 ml/min/1.73 m(2). Twenty-three percent had a reduced left ventricular ejection fraction (LVEF), thirty-one percent were diabetics and twenty-three percent underwent heart valve surgery. The incidence of AKI was 5.3% based on RIFLE risk and 12.0% based on the AKIN criterion. AKI was associated with a reduced LVEF, diuretic use, anemia, heart valve surgery, duration of extracorporeal circulation, hemodynamic instability and the use of albumin, pentastarch 10% and transfusions. There was an important dose-dependent AKI risk associated with the administration of albumin, which also paralleled a higher prevalence of concomitant risk factors for AKI. To address any indication bias, we derived a propensity score predicting the likelihood to receive albumin and matched 141 cases to 141 controls with a similar risk profile. In this analysis, albumin was associated with an increased AKI risk (RIFLE risk: 12% versus 5%, P = 0.03; AKIN stage 1: 28% versus 13%, P = 0.002). We repeated this methodology in patients without postoperative hemodynamic instability and still identified an association between the use of albumin and AKI. Albumin administration was associated with a dose-dependent risk of AKI and remained significant using a propensity
Austin, Peter C; Schuster, Tibor
2016-10-01
Observational studies are increasingly being used to estimate the effect of treatments, interventions and exposures on outcomes that can occur over time. Historically, the hazard ratio, which is a relative measure of effect, has been reported. However, medical decision making is best informed when both relative and absolute measures of effect are reported. When outcomes are time-to-event in nature, the effect of treatment can also be quantified as the change in mean or median survival time due to treatment and the absolute reduction in the probability of the occurrence of an event within a specified duration of follow-up. We describe how three different propensity score methods, propensity score matching, stratification on the propensity score and inverse probability of treatment weighting using the propensity score, can be used to estimate absolute measures of treatment effect on survival outcomes. These methods are all based on estimating marginal survival functions under treatment and lack of treatment. We then conducted an extensive series of Monte Carlo simulations to compare the relative performance of these methods for estimating the absolute effects of treatment on survival outcomes. We found that stratification on the propensity score resulted in the greatest bias. Caliper matching on the propensity score and a method based on earlier work by Cole and Hernán tended to have the best performance for estimating absolute effects of treatment on survival outcomes. When the prevalence of treatment was less extreme, then inverse probability of treatment weighting-based methods tended to perform better than matching-based methods. © The Author(s) 2014.
Spertus, Jacob V; Normand, Sharon-Lise T
2018-04-23
High-dimensional data provide many potential confounders that may bolster the plausibility of the ignorability assumption in causal inference problems. Propensity score methods are powerful causal inference tools, which are popular in health care research and are particularly useful for high-dimensional data. Recent interest has surrounded a Bayesian treatment of propensity scores in order to flexibly model the treatment assignment mechanism and summarize posterior quantities while incorporating variance from the treatment model. We discuss methods for Bayesian propensity score analysis of binary treatments, focusing on modern methods for high-dimensional Bayesian regression and the propagation of uncertainty. We introduce a novel and simple estimator for the average treatment effect that capitalizes on conjugacy of the beta and binomial distributions. Through simulations, we show the utility of horseshoe priors and Bayesian additive regression trees paired with our new estimator, while demonstrating the importance of including variance from the treatment regression model. An application to cardiac stent data with almost 500 confounders and 9000 patients illustrates approaches and facilitates comparison with existing alternatives. As measured by a falsifiability endpoint, we improved confounder adjustment compared with past observational research of the same problem. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Austin, Peter C
2014-03-30
Propensity score methods are increasingly being used to estimate causal treatment effects in observational studies. In medical and epidemiological studies, outcomes are frequently time-to-event in nature. Propensity-score methods are often applied incorrectly when estimating the effect of treatment on time-to-event outcomes. This article describes how two different propensity score methods (matching and inverse probability of treatment weighting) can be used to estimate the measures of effect that are frequently reported in randomized controlled trials: (i) marginal survival curves, which describe survival in the population if all subjects were treated or if all subjects were untreated; and (ii) marginal hazard ratios. The use of these propensity score methods allows one to replicate the measures of effect that are commonly reported in randomized controlled trials with time-to-event outcomes: both absolute and relative reductions in the probability of an event occurring can be determined. We also provide guidance on variable selection for the propensity score model, highlight methods for assessing the balance of baseline covariates between treated and untreated subjects, and describe the implementation of a sensitivity analysis to assess the effect of unmeasured confounding variables on the estimated treatment effect when outcomes are time-to-event in nature. The methods in the paper are illustrated by estimating the effect of discharge statin prescribing on the risk of death in a sample of patients hospitalized with acute myocardial infarction. In this tutorial article, we describe and illustrate all the steps necessary to conduct a comprehensive analysis of the effect of treatment on time-to-event outcomes. © 2013 The authors. Statistics in Medicine published by John Wiley & Sons, Ltd.
Applying Propensity Score Methods in Medical Research: Pitfalls and Prospects
Luo, Zhehui; Gardiner, Joseph C.; Bradley, Cathy J.
2012-01-01
The authors review experimental and nonexperimental causal inference methods, focusing on assumptions for the validity of instrumental variables and propensity score (PS) methods. They provide guidance in four areas for the analysis and reporting of PS methods in medical research and selectively evaluate mainstream medical journal articles from 2000 to 2005 in the four areas, namely, examination of balance, overlapping support description, use of estimated PS for evaluation of treatment effect, and sensitivity analyses. In spite of the many pitfalls, when appropriately evaluated and applied, PS methods can be powerful tools in assessing average treatment effects in observational studies. Appropriate PS applications can create experimental conditions using observational data when randomized controlled trials are not feasible and, thus, lead researchers to an efficient estimator of the average treatment effect. PMID:20442340
Crown, William H
2014-02-01
This paper examines the use of propensity score matching in economic analyses of observational data. Several excellent papers have previously reviewed practical aspects of propensity score estimation and other aspects of the propensity score literature. The purpose of this paper is to compare the conceptual foundation of propensity score models with alternative estimators of treatment effects. References are provided to empirical comparisons among methods that have appeared in the literature. These comparisons are available for a subset of the methods considered in this paper. However, in some cases, no pairwise comparisons of particular methods are yet available, and there are no examples of comparisons across all of the methods surveyed here. Irrespective of the availability of empirical comparisons, the goal of this paper is to provide some intuition about the relative merits of alternative estimators in health economic evaluations where nonlinearity, sample size, availability of pre/post data, heterogeneity, and missing variables can have important implications for choice of methodology. Also considered is the potential combination of propensity score matching with alternative methods such as differences-in-differences and decomposition methods that have not yet appeared in the empirical literature.
Wellner, Ulrich Friedrich; Lapshyn, Hryhoriy; Bartsch, Detlef K; Mintziras, Ioannis; Hopt, Ulrich Theodor; Wittel, Uwe; Krämling, Hans-Jörg; Preissinger-Heinzel, Hubert; Anthuber, Matthias; Geissler, Bernd; Köninger, Jörg; Feilhauer, Katharina; Hommann, Merten; Peter, Luisa; Nüssler, Natascha C; Klier, Thomas; Mansmann, Ulrich; Keck, Tobias
2017-02-01
The aim of this study was to assess intraoperative, postoperative, and oncologic outcome in patients undergoing laparoscopic distal pancreatectomy (LDP) versus open distal pancreatectomy (ODP) for benign and malignant lesions of the pancreas. Data from patients undergoing distal pancreatic resection were extracted from the StuDoQ|Pancreas registry of the German Society for General and Visceral Surgery. After propensity score case matching, groups of LDP and ODP were compared regarding demography, comorbidities, operative details, histopathology, and perioperative outcome. At the time of data extraction, the StuDoQ|Pancreas registry included over 3000 pancreatic resections from over 50 surgical departments in Germany. Data from 353 patients undergoing ODP (n = 254) or LDP (n = 99) from September 2013 to February 2016 at 29 institutions were included in the analysis. Baseline data showed a strong selection bias in LDP patients, which disappeared after 1:1 propensity score matching. A comparison of the matched groups disclosed a significantly longer operation time, higher rate of spleen preservation, more grade A pancreatic fistula, shorter hospital stay, and increased readmissions for LDP. In the small group of patients operated for pancreatic cancer, a lower lymph node yield with a lower lymph node ratio was apparent in LDP. LDP needed more time but potential advantages include increased spleen preservation and shorter hospital stay, as well as a trend for less transfusion, ventilation, and mortality. LDP for pancreatic cancer was performed rarely and will need critical evaluation in the future. Data from a prospective randomized registry trial is needed to confirm these results.
Antenatal Maternity Leave and Childbirth Using the First Baby Study: A Propensity Score Analysis.
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.
Mollon, Lea; Bhattacharjee, Sandipan
2017-12-04
Little is known regarding the health-related quality of life among myocardial infarction (MI) survivors in the United States. The purpose of this population-based study was to identify differences in health-related quality of life domains between MI survivors and propensity score matched controls. This retrospective, cross-sectional matched case-control study examined differences in health-related quality of life (HRQoL) among MI survivors of myocardial infarction compared to propensity score matched controls using data from the 2015 Behavioral Risk Factor Surveillance System (BRFSS) survey. Propensity scores were generated via logistic regression for MI survivors and controls based on gender, race/ethnicity, age, body mass index (BMI), smoking status, and comorbidities. Chi-square tests were used to compare differences between MI survivors to controls for demographic variables. A multivariate analysis of HRQoL domains estimated odds ratios. Life satisfaction, sleep quality, and activity limitations were estimated using binary logistic regression. Social support, perceived general health, perceived physical health, and perceived mental health were estimated using multinomial logistic regression. Significance was set at p < 0.05. The final sample consisted of 16,729 MI survivors matched to 50,187 controls (n = 66,916). Survivors were approximately 2.7 times more likely to report fair/poor general health compared to control (AOR = 2.72, 95% CI: 2.43-3.05) and 1.5 times more likely to report limitations to daily activities (AOR = 1.46, 95% CI: 1.34-1.59). Survivors were more likely to report poor physical health >15 days in the month (AOR = 1.63, 95% CI: 1.46-1.83) and poor mental health >15 days in the month (AOR = 1.25, 95% CI: 1.07-1.46) compared to matched controls. There was no difference in survivors compared to controls in level of emotional support (rarely/never: AOR = 0.75, 95% CI: 0.48-1.18; sometimes: AOR = 0.73, 95% CI: 0
Kim, Chang Woo; Cho, Min Soo; Baek, Se Jin; Hur, Hyuk; Min, Byung Soh; Kang, Jeonghyun; Baik, Seung Hyuk; Lee, Kang Young; Kim, Nam Kyu
2015-03-01
The aim of this study was to investigate oncologic outcomes, as well as perioperative and pathologic outcomes, of single-incision laparoscopic anterior resection (SILAR) compared with conventional laparoscopic anterior resection (CLAR) for sigmoid colon cancer using propensity-score matching analysis. From July 2009 through April 2012, a total of 407 patients underwent laparoscopic anterior resection for sigmoid colon cancer. Data on short- and long-term outcomes were collected prospectively and reviewed. Propensity-score matching was applied at a ratio of 1:2 comparing the SILAR (n = 60) and CLAR (n = 120) groups. There was no difference in operation time, estimated blood loss, time to soft diet, and length of hospital stay; however, the SILAR group showed less pain on postoperative day 2 (mean 2.6 vs. 3.6; p = 0.000) and shorter length of incision (3.3 vs. 7.7 cm; p = 0.000) compared with the CLAR group. Morbidity, mortality, and pathologic outcomes were similar in both groups. The 3-year overall survival rates were 94.5 versus 97.1% (p = 0.223), and disease-free survival rates were 89.5 versus 87.4% (p = 0.751) in the SILAR and CLAR groups, respectively. The long-term oncologic outcomes, as well as short-term outcomes, of SILAR are comparable with those of CLAR. Although SILAR might have some technical difficulties, it appears to be a safe and feasible option, with better cosmetic results.
Hou, Ting; Sun, Yidi; Li, Junyi; Liu, Chenglin; Wang, Zhen; Li, Yixue; Lu, Yuan
2017-01-01
Most patients with early stage endometrial endometrioid adenocarcinoma (EEAC) are treated with hysterectomy and bilateral oophorectomy. But this surgical menopause leads to long-term sequelae for premenopausal women, especially for young women of childbearing age. This population-based study was to evaluate the safety of ovarian preservation in young women with stage I EEAC. Patients of age 50 or younger with stage I EEAC were explored from the Surveillance, Epidemiology and End Results program database during 2004 to 2013. Propensity score matching was used to randomize the data set and reduce the selection biases of doctors. Univariate analysis and multivariate cox proportional hazards model were utilized to estimate the safety of ovarian preservation. A total of 7183 patients were identified, and ovarian preservation was performed in 863 (12 %) patients. Compared with women treated with oophorectomy, patients with ovarian preservation significantly tend to be younger at diagnosis (P-value < 0.001) and more likely diagnosed as stage IA EEAC, to have better differentiated tumor tissues and smaller tumors, as well as less likely to undergo radiation and lymphadenectomy. 863 patients treated with oophorectomy were selected by propensity score matching. After propensity score matching, the differences of all characteristics between ovarian preservation and oophorectomy were not significant and potential confounders in the two groups decreased. In univariate analysis of matched population, ovarian preservation had no effect on overall (P-value=0.928) and cancer-specific (P-value=0.390) mortality. In propensityadjusted multivariate analysis, ovarian preservation was not significantly associated with overall (HR=0.69, 95%CI=0.41-1.68, P-value=0.611) and cancer-specific (HR=1.65, 95%CI=0.54-5.06, Pvalue= 0.379) survival. Ovarian preservation is safe for young women with stage I EEAC, which is not significantly associated with overall and cancer-specific mortality
Zhang, Zhongheng; Chen, Kun; Ni, Hongying
2015-01-01
Observational studies have linked hypocalcemia with adverse clinical outcome in critically ill patients. However, calcium supplementation has never been formally investigated for its beneficial effect in critically ill patients. To investigate whether calcium supplementation can improve 28-day survival in adult critically ill patients. Secondary analysis of a large clinical database consisting over 30,000 critical ill patients was performed. Multivariable analysis was performed to examine the independent association of calcium supplementation and 28-day morality. Furthermore, propensity score matching technique was employed to investigate the role of calcium supplementation in improving survival. none. Primary outcome was the 28-day mortality. 90-day mortality was used as secondary outcome. A total of 32,551 adult patients, including 28,062 survivors and 4489 non-survivors (28-day mortality rate: 13.8 %) were included. Calcium supplementation was independently associated with improved 28-day mortality after adjusting for confounding variables (hazard ratio: 0.51; 95 % CI 0.47-0.56). Propensity score matching was performed and the after-matching cohort showed well balanced covariates. The results showed that calcium supplementation was associated with improved 28- and 90-day mortality (p < 0.05 for both Log-rank test). In adult critically ill patients, calcium supplementation during their ICU stay improved 28-day survival. This finding supports the use of calcium supplementation in critically ill patients.
Sasidharan, Lekshmi; Donnell, Eric T
2014-10-01
Accurate estimation of the expected number of crashes at different severity levels for entities with and without countermeasures plays a vital role in selecting countermeasures in the framework of the safety management process. The current practice is to use the American Association of State Highway and Transportation Officials' Highway Safety Manual crash prediction algorithms, which combine safety performance functions and crash modification factors, to estimate the effects of safety countermeasures on different highway and street facility types. Many of these crash prediction algorithms are based solely on crash frequency, or assume that severity outcomes are unchanged when planning for, or implementing, safety countermeasures. Failing to account for the uncertainty associated with crash severity outcomes, and assuming crash severity distributions remain unchanged in safety performance evaluations, limits the utility of the Highway Safety Manual crash prediction algorithms in assessing the effect of safety countermeasures on crash severity. This study demonstrates the application of a propensity scores-potential outcomes framework to estimate the probability distribution for the occurrence of different crash severity levels by accounting for the uncertainties associated with them. The probability of fatal and severe injury crash occurrence at lighted and unlighted intersections is estimated in this paper using data from Minnesota. The results show that the expected probability of occurrence of fatal and severe injury crashes at a lighted intersection was 1 in 35 crashes and the estimated risk ratio indicates that the respective probabilities at an unlighted intersection was 1.14 times higher compared to lighted intersections. The results from the potential outcomes-propensity scores framework are compared to results obtained from traditional binary logit models, without application of propensity scores matching. Traditional binary logit analysis suggests that
Uchida, Mitsuo; Morita, Hiroshi
2018-06-01
Although long work hours have been associated with various physical health problems, studies of their association with mental health have yielded inconsistent results, due to differences in study settings, study outcome and/or unmeasured background factors. In this study, we used a propensity score method to evaluate the association between work hours and depressive state. A total of 467 Japanese white-collar workers were surveyed and divided into long and regular work hour groups according to overtime work records. Propensity score matching was performed based on 32 individual background and workplace factors, yielding 74 pairs of propensity-matched subjects. CES-D score, an indicator of depressive state, did not differ significantly among the two groups (p=0.203). However, work motivation, work control, social support and emotional stability correlated with CES-D score. These findings suggest that work control and social support factors are more associated with depressive state than control of work hours. These results also suggest that it is possible to use propensity score matching to evaluate the association between work hours and mental health in occupational study settings. Further studies, in larger populations, are required to determine the association between work hours and mental health parameters.
Choo, Min Soo; Jeong, Chang Wook; Song, Cheryn; Jeon, Hwang Gyun; Seo, Seong Il; Hong, Sung Kyu; Byun, Seok-Soo; Chung, Jin Soo; Hong, Sung-Hoo; Hwang, Eu Chang; Kim, Hyeon Hoe; Kwak, Cheol
2017-10-01
We evaluated the clinicopathologic characteristics and prognosis of Xp11.2 translocation (Xp11.2t) renal cell carcinoma (RCC) from a multicenter study and compare them with clear-cell RCC using a propensity score matching analysis. Between 2004 and 2013, 8384 consecutive patients from 7 institutions who were diagnosed with RCC were reviewed, and the pathologically confirmed Xp11.2t cases were enrolled. The oncological outcomes of Xp11.2t were compared with those of clear-cell RCC by selecting matched cases using 1:3 propensity score matching methods in a precollected clear-cell RCC data set from our hospital. The patients were divided into 2 subgroups on the basis of age of onset, either before (early) or after (late) 45 years old. Xp11.2t was found in 61 cases, corresponding to 0.72% of RCC cases for the 10 years. The mean age was 38.2 ± 19.4 years, and the mean tumor size was 6.2 ± 3.9 cm. The Xp11.2t cases were at more advanced stages and showed tendencies to involve lymph nodes at diagnosis. After the matching, there were no significant differences in recurrence-free and overall survival compared with clear-cell RCC. The age of incidence for Xp11.2t had a bimodal distribution, which was most common in the 30s and smaller peak in the 60s. Xp11.2t corresponded to a significantly worse prognosis for overall survival in late onset (after 45 years) subgroup (P = .038; hazard ratio, 3.199; 95% confidence interval, 1.065-9.609). This neoplasm has more aggressive clinicopathologic features at diagnosis. In older patients with onset age > 45 years, Xp11.2t showed a significantly worse prognosis than clear-cell RCC. Copyright © 2017 Elsevier Inc. All rights reserved.
Drabik, Anna; Büscher, Guido; Thomas, Karsten; Graf, Christian; Müller, Dirk; Stock, Stephanie
2012-08-01
This study aimed to assess the impact of a nationwide German diabetes mellitus disease management program (DMP) on survival time and costs in comparison to routine care. The authors conducted a retrospective observational cohort study using routine administration data from Germany's largest sickness fund to identify insured suffering from diabetes in 2002. A total of 95,443 insured with type 2 diabetes mellitus who were born before January 1, 1962 met the defined inclusion criteria, resulting in 19,888 pairs of DMP participants and nonparticipants matched for socioeconomic and health status using propensity score matching methods. This is the first time propensity score matching has been used to evaluate a survival benefit of DMPs. In the time frame analyzed (3 years), mean survival time for the DMP group was 1045 days vs. 985 days for the routine care group (P<0.001). Mean daily hospital and total costs (including DMP administration and medical costs) were lower for the DMP group in the case of deceased insureds (92€ vs. 139€ and 122€ vs. 169€, respectively) as well as for censored observations (6€ vs. 7€ and 12.9€ vs. 13.4€, respectively). Mean daily drug costs were slightly lower for deceased insured in the DMP group (difference 0.6€), while no identifiable difference was found for censored observations. In this study, insured who were enrolled in a DMP for diabetes mellitus in the German Statutory Health Insurance showed a significant benefit in survival time. They also incurred lower costs compared to propensity score matched insured in routine care.
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
Ensing, Sabine; Abu-Hanna, Ameen; Roseboom, Tessa J; Repping, Sjoerd; van der Veen, Fulco; Mol, Ben Willem J; Ravelli, Anita C J
2015-08-01
To study risk of birth asphyxia and related morbidity among term singletons born after medically assisted reproduction (MAR). Population cohort study. Not applicable. A total of 1,953,932 term singleton pregnancies selected from a national registry for 1999-2011. None. Primary outcome Apgar score <4; secondary outcomes Apgar score <7, intrauterine fetal death, perinatal mortality, congenital anomalies, small for gestational age, asphyxia related morbidity, and cesarean delivery. The risks of birth asphyxia and related morbidity were calculated in women who conceived either through MAR or spontaneously (SC), with a subgroup analysis for in vitro fertilization (IVF). An additional propensity score matching analysis was performed with matching on multiple maternal baseline covariates (maternal age, ethnicity, socioeconomic status, parity, year of birth, and preexistent diseases). Each MAR pregnancy was matched to three SC controls. Relative to SC, the MAR singletons had an increased risk of adverse neonatal outcomes including Apgar score <4 (adjusted odds ratio [OR] 1.29; 95% CI, 1.14-1.46) and intrauterine fetal death (adjusted OR 1.61; 95% CI, 1.35-1.91). After propensity score matching, the risk of an Apgar score <4 was comparable between MAR and SC singletons (OR 0.99; 95% CI, 0.87-1.14). Cesarean delivery for both fetal distress and nonprogressive labor occurred more among MAR pregnancies compared with SC pregnancies. Term singletons conceived after MAR have an increased risk of morbidity related to birth asphyxia. Because this is mainly due to maternal characteristics, obstetric caregivers should be aware that the increased rates of cesareans reflect the behavior of women and physicians rather than increased perinatal complications. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
Giordano, Salvatore; Garvey, Patrick B; Baumann, Donald P; Liu, Jun; Butler, Charles E
2017-03-01
Prior abdominal wall radiotherapy (XRT) adversely affects wound healing, but data are limited on how prior XRT may affect abdominal wall reconstruction (AWR) outcomes. The purpose of this study was to determine whether prior abdominal wall radiotherapy is associated with a higher incidence of complications following AWR for a hernia or oncologic resection defect. We performed a retrospective study of consecutive patients who underwent complex AWR using acellular dermal matrix (ADM) at a single center. We compared outcomes between patients who underwent prior XRT that directly involved the abdominal wall and those who did not receive XRT. Propensity score match-paired and multivariate analyses were performed. A total of 511 patients (130 [25.4 %] with prior XRT; 381 [74.6 %] without prior XRT) underwent AWR with ADM for repair of a complex hernia or oncologic resection defect. Mean follow-up was 31.4 months, mean XRT dose was 48.9 Gy, and mean time between XRT and reconstruction was 19.2 months. XRT AWR patients underwent more flap reconstructions (14.6 vs. 5.0 %, P < 0.001) but fewer component separations (61.5 vs. 71.4 %; P = 0.036) than non-XRT AWR patients. The two groups had similar rates of hernia recurrence (8.5 vs. 9.4 %; P = 0.737) and surgical site occurrence (25.4 vs. 23.4 %; P = 0.640). In the propensity score-matched subgroups, there were no differences in hernia recurrence, surgical site occurrence, and wound healing complication rates. Prior XRT does not adversely affect outcomes in AWR. However, surgeons should be aware of the higher likelihood of needing a soft tissue flap reconstruction for soft tissue replacement when performing AWR after XRT.
Burden, Anne; Roche, Nicolas; Miglio, Cristiana; Hillyer, Elizabeth V; Postma, Dirkje S; Herings, Ron Mc; Overbeek, Jetty A; Khalid, Javaria Mona; van Eickels, Daniela; Price, David B
2017-01-01
Cohort matching and regression modeling are used in observational studies to control for confounding factors when estimating treatment effects. Our objective was to evaluate exact matching and propensity score methods by applying them in a 1-year pre-post historical database study to investigate asthma-related outcomes by treatment. We drew on longitudinal medical record data in the PHARMO database for asthma patients prescribed the treatments to be compared (ciclesonide and fine-particle inhaled corticosteroid [ICS]). Propensity score methods that we evaluated were propensity score matching (PSM) using two different algorithms, the inverse probability of treatment weighting (IPTW), covariate adjustment using the propensity score, and propensity score stratification. We defined balance, using standardized differences, as differences of <10% between cohorts. Of 4064 eligible patients, 1382 (34%) were prescribed ciclesonide and 2682 (66%) fine-particle ICS. The IPTW and propensity score-based methods retained more patients (96%-100%) than exact matching (90%); exact matching selected less severe patients. Standardized differences were >10% for four variables in the exact-matched dataset and <10% for both PSM algorithms and the weighted pseudo-dataset used in the IPTW method. With all methods, ciclesonide was associated with better 1-year asthma-related outcomes, at one-third the prescribed dose, than fine-particle ICS; results varied slightly by method, but direction and statistical significance remained the same. We found that each method has its particular strengths, and we recommend at least two methods be applied for each matched cohort study to evaluate the robustness of the findings. Balance diagnostics should be applied with all methods to check the balance of confounders between treatment cohorts. If exact matching is used, the calculation of a propensity score could be useful to identify variables that require balancing, thereby informing the choice of
Burden, Anne; Roche, Nicolas; Miglio, Cristiana; Hillyer, Elizabeth V; Postma, Dirkje S; Herings, Ron MC; Overbeek, Jetty A; Khalid, Javaria Mona; van Eickels, Daniela; Price, David B
2017-01-01
Background Cohort matching and regression modeling are used in observational studies to control for confounding factors when estimating treatment effects. Our objective was to evaluate exact matching and propensity score methods by applying them in a 1-year pre–post historical database study to investigate asthma-related outcomes by treatment. Methods We drew on longitudinal medical record data in the PHARMO database for asthma patients prescribed the treatments to be compared (ciclesonide and fine-particle inhaled corticosteroid [ICS]). Propensity score methods that we evaluated were propensity score matching (PSM) using two different algorithms, the inverse probability of treatment weighting (IPTW), covariate adjustment using the propensity score, and propensity score stratification. We defined balance, using standardized differences, as differences of <10% between cohorts. Results Of 4064 eligible patients, 1382 (34%) were prescribed ciclesonide and 2682 (66%) fine-particle ICS. The IPTW and propensity score-based methods retained more patients (96%–100%) than exact matching (90%); exact matching selected less severe patients. Standardized differences were >10% for four variables in the exact-matched dataset and <10% for both PSM algorithms and the weighted pseudo-dataset used in the IPTW method. With all methods, ciclesonide was associated with better 1-year asthma-related outcomes, at one-third the prescribed dose, than fine-particle ICS; results varied slightly by method, but direction and statistical significance remained the same. Conclusion We found that each method has its particular strengths, and we recommend at least two methods be applied for each matched cohort study to evaluate the robustness of the findings. Balance diagnostics should be applied with all methods to check the balance of confounders between treatment cohorts. If exact matching is used, the calculation of a propensity score could be useful to identify variables that require
Isogai, Toshiaki; Yasunaga, Hideo; Matsui, Hiroki; Tanaka, Hiroyuki; Horiguchi, Hiromasa; Fushimi, Kiyohide
2015-05-01
Fulminant myocarditis (FM) is a rare but life-threatening disease. Intravenous immunoglobulin (IVIG) is not recommended for acute or chronic myocarditis in Western nations owing to the lack of rigorous evidence, but it is widely used in other countries, including Japan. This nationwide retrospective cohort study focused on evaluating the effect of IVIG in FM patients. Using the Diagnosis Procedure Combination database in Japan, we identified 603 FM patients aged ≥16 years who received mechanical circulatory support within 7 days after admission. We performed propensity score analyses to compare the in-hospital mortality and total costs between IVIG users (n = 220; 36.5%) and nonusers (n = 383; 63.5%). Among propensity score-matched patients (164 pairs), there was no significant difference in in-hospital mortality between IVIG users and nonusers (36.6% vs 37.2%; P = .909). A multivariable logistic regression analysis showed no significant association between IVIG use and in-hospital mortality (adjusted odds ratio 0.91; 95% confidence interval 0.52 to 1.58; P = .733). The median total costs were significantly higher for IVIG users than for nonusers (US $44,226 vs $33,280; P < .001). IVIG for FM was not significantly associated with a decrease in in-hospital mortality. Copyright © 2015 Elsevier Inc. All rights reserved.
ERIC Educational Resources Information Center
Vaughan, Angela L.; Lalonde, Trent L.; Jenkins-Guarnieri, Michael A.
2014-01-01
Many researchers assessing the efficacy of educational programs face challenges due to issues with non-randomization and the likelihood of dependence between nested subjects. The purpose of the study was to demonstrate a rigorous research methodology using a hierarchical propensity score matching method that can be utilized in contexts where…
Applications of Small Area Estimation to Generalization with Subclassification by Propensity Scores
ERIC Educational Resources Information Center
Chan, Wendy
2018-01-01
Policymakers have grown increasingly interested in how experimental results may generalize to a larger population. However, recently developed propensity score-based methods are limited by small sample sizes, where the experimental study is generalized to a population that is at least 20 times larger. This is particularly problematic for methods…
Do, Mai P; Kincaid, D Lawrence
2006-01-01
Shabuj Chaya is a weekly television drama broadcast during a 13-week period in Bangladesh in 2000. It used an entertainment-education format to increase health knowledge and to promote visits to health clinic and modern contraceptive use. The purpose of this article is to demonstrate how a relatively new statistical technique, propensity score matching in conjunction with structural equation modeling, can be used to obtain an unbiased estimate of changes in health outcomes that can be attributed to exposure to the drama. The analysis is conducted with data from an after-only, cross-sectional survey of 4,492 men and women from the intended audience. The results from propensity score matching approximate what would be expected from a randomized control group design.
Soutome, Sakiko; Yanamoto, Souichi; Funahara, Madoka; Hasegawa, Takumi; Komori, Takahide; Yamada, Shin-Ichi; Kurita, Hiroshi; Yamauchi, Chika; Shibuya, Yasuyuki; Kojima, Yuka; Nakahara, Hirokazu; Oho, Takahiko; Umeda, Masahiro
2017-08-01
The aim of this study was to investigate the effectiveness of oral care in prevention of postoperative pneumonia associated with esophageal cancer surgery.Postoperative pneumonia is a severe adverse event associated with esophageal cancer surgery. It is thought to be caused by aspiration of oropharyngeal fluid containing pathogens. However, the relationship between oral health status and postoperative pneumonia has not been well investigated.This study included 539 patients with esophageal cancer undergoing surgery at 1 of 7 university hospitals. While 306 patients received perioperative oral care, 233 did not. Various clinical factors as well as occurrence of postoperative pneumonia were retrospectively evaluated. Propensity-score matching was performed to minimize selection biases associated with comparison of retrospective data between the oral care and control groups. Factors related to postoperative pneumonia were analyzed by logistic regression analysis.Of the original 539 patients, 103 (19.1%) experienced postoperative pneumonia. The results of multivariate analysis of the 420 propensity score-matched patients revealed longer operation time, postoperative dysphagia, and lack of oral care intervention to be significantly correlated with postoperative pneumonia.The present findings demonstrate that perioperative oral care can reduce the risk of postoperative pneumonia in patients undergoing esophageal cancer surgery.
ERIC Educational Resources Information Center
McCaffrey, Daniel F.; Ridgeway, Greg; Morral, Andrew R.
2004-01-01
Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate…
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.
Self-reported hand washing behaviors and foodborne illness: a propensity score matching approach.
Ali, Mir M; Verrill, Linda; Zhang, Yuanting
2014-03-01
Hand washing is a simple and effective but easily overlooked way to reduce cross-contamination and the transmission of foodborne pathogens. In this study, we used the propensity score matching methodology to account for potential selection bias to explore our hypothesis that always washing hands before food preparation tasks is associated with a reduction in the probability of reported foodborne illness. Propensity score matching can simulate random assignment to a condition so that pretreatment observable differences between a treatment group and a control group are homogenous on all the covariates except the treatment variable. Using the U.S. Food and Drug Administration's 2010 Food Safety Survey, we estimated the effect of self-reported hand washing behavior on the probability of self-reported foodborne illness. Our results indicate that reported washing of hands with soap always before food preparation leads to a reduction in the probability of reported foodborne illness.
Staffa, Steven J; Zurakowski, David
2018-01-09
In clinical research, the gold standard level of evidence is the randomized controlled trial (RCT). The availability of nonrandomized retrospective data is growing; however, a primary concern of analyzing such data is comparability of the treatment groups with respect to confounding variables. Propensity score matching (PSM) aims to equate treatment groups with respect to measured baseline covariates to achieve a comparison with reduced selection bias. It is a valuable statistical methodology that mimics the RCT, and it may create an "apples to apples" comparison while reducing bias due to confounding. PSM can improve the quality of anesthesia research and broaden the range of research opportunities. PSM is not necessarily a magic bullet for poor-quality data, but rather may allow the researcher to achieve balanced treatment groups similar to a RCT when high-quality observational data are available. PSM may be more appealing than the common approach of including confounders in a regression model because it allows for a more intuitive analysis of a treatment effect between 2 comparable groups.We present 5 steps that anesthesiologists can use to successfully implement PSM in their research with an example from the 2015 Pediatric National Surgical Quality Improvement Program: a validated, annually updated surgery and anesthesia pediatric database. The first step of PSM is to identify its feasibility with regard to the data at hand and ensure availability of data on any potential confounders. The second step is to obtain the set of propensity scores from a logistic regression model with treatment group as the outcome and the balancing factors as predictors. The third step is to match patients in the 2 treatment groups with similar propensity scores, balancing all factors. The fourth step is to assess the success of the matching with balance diagnostics, graphically or analytically. The fifth step is to apply appropriate statistical methodology using the propensity
Perlas, Anahi; Chan, Vincent W S; Beattie, Scott
2016-10-01
This propensity score-matched cohort study evaluates the effect of anesthetic technique on a 30-day mortality after total hip or knee arthroplasty. All patients who had hip or knee arthroplasty between January 1, 2003, and December 31, 2014, were evaluated. The principal exposure was spinal versus general anesthesia. The primary outcome was 30-day mortality. Secondary outcomes were (1) perioperative myocardial infarction; (2) a composite of major adverse cardiac events that includes cardiac arrest, myocardial infarction, or newly diagnosed arrhythmia; (3) pulmonary embolism; (4) major blood loss; (5) hospital length of stay; and (6) operating room procedure time. A propensity score-matched-pair analysis was performed using a nonparsimonious logistic regression model of regional anesthetic use. We identified 10,868 patients, of whom 8,553 had spinal anesthesia and 2,315 had general anesthesia. Ninety-two percent (n = 2,135) of the patients who had general anesthesia were matched to similar patients who did not have general anesthesia. In the matched cohort, the 30-day mortality rate was 0.19% (n = 4) in the spinal anesthesia group and 0.8% (n = 17) in the general anesthesia group (risk ratio, 0.42; 95% CI, 0.21 to 0.83; P = 0.0045). Spinal anesthesia was also associated with a shorter hospital length of stay (5.7 vs. 6.6 days; P < 0.001). The results of this observational, propensity score-matched cohort study suggest a strong association between spinal anesthesia and lower 30-day mortality, as well as a shorter hospital length of stay, after elective joint replacement surgery.
Ambrogi, Vincenzo; Mineo, Tommaso Claudio
2017-02-01
To demonstrate the effectiveness of a comprehensive program of rehabilitation therapy in patients undergoing thymectomy for myasthenia gravis (MG). From 2005 to 2010, 46 consecutive patients affected by MG underwent a rehabilitation program both before and after thymectomy. We matched each patient with a "control patient" who underwent thymectomy within the period 1999 to 2004 with no preoperative rehabilitation, who had the closest propensity score matching. All patients but 2 were able to complete the intended program. Eighteen patients (41%) experienced mild fatigue (>25 at MG quantitative score). Propensity score selected a group of 17 patients for the matching process. The group of patients who underwent the rehabilitation program showed significant preoperative improvement associated with a reduced operative risk, a decreased early postoperative morbidity, a lower rate of postoperative intensive care unit needed (12% vs 35%; P = 0.01) and a shorter hospital stay (3 vs 5 days; P = 0.04). After the expected perioperative decline, all major myasthenic outcomes demonstrated a significant faster recovery at 3 months. Complete stable remission did not reveal significant differences. Exercise is not necessarily a contraindication in MG, and rehabilitation can be safely performed before and after thymectomy, reducing operative risks and decreasing recovery time. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCMECME OBJECTIVES: Upon completion of this article, the reader should be able to do the following: (1) appreciate the benefits of physical therapy in individuals with myasthenia gravis; (2) describe the benefits of physical therapy on postoperative morbidity in myasthenia gravis patients who undergo thymectomy; and (3) incorporate appropriate rehabilitation into the treatment plan of patient with myasthenia gravis. AdvancedACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation
Fortún, Jesús; Muriel, Alfonso; Martín-Dávila, Pilar; Montejo, Miguel; Len, Oscar; Torre-Cisneros, Julian; Carratalá, Jordi; Muñoz, Patricia; Fariñas, Carmen; Moreno, Asunción; Fresco, Gema; Goikoetxea, Josune; Gavaldá, Joan; Pozo, Juan Carlos; Bodro, Marta; Vena, Antonio; Casafont, Fernando; Cervera, Carlos; Silva, José Tiago; Aguado, José M
2016-04-01
Targeted prophylaxis has proven to be an efficient strategy in liver transplantation recipients (LTRs). The aim of this study was to compare the effectiveness and safety of caspofungin with that of fluconazole in high-risk (HR) LTRs. Caspofungin and fluconazole were compared in a multicenter, retrospective, cohort study in HR-LTRs in Spain. Outcomes were assessed at 180 days after transplantation. A propensity score approach was applied. During the study period (2005-2012), we analyzed 195 HR-LTRs from 9 hospitals. By type of prophylaxis, 97 patients received caspofungin and 98 received fluconazole. Of a total of 17 (8.7%) global invasive fungal infections (IFIs), breakthrough IFIs accounted for 11 (5.6%) and invasive aspergillosis (IA) accounted for 6 (3.1%). By univariate analysis, no differences were observed in the prevention of global IFIs. However, caspofungin was associated with a significant reduction in the rate of breakthrough IFIs (2.1% versus 9.2%, P = 0.04). In patients requiring dialysis (n = 62), caspofungin significantly reduced the frequency of breakthrough IFIs (P = 0.03). The propensity score analysis confirmed a significant reduction in the frequency of IA in patients receiving caspofungin (absolute risk reduction, 0.06; 95% confidence interval [CI], 0.001-0.11; P = 0.044). Linear regression analysis revealed a significant decrease in blood alanine aminotransferase levels and a significant increase in bilirubin levels after administration of caspofungin. Caspofungin and fluconazole have similar efficacy for the prevention of global IFIs in HR-LTRs in this observational, multicenter cohort study. However, caspofungin was associated with a significant reduction of breakthrough IFIs and, after adjusting for confounders, caspofungin was associated with a lower rate of IA. This benefit is probably more favorable in patients on dialysis. Caspofungin is safe in HR-LTRs, although bilirubin levels may be increased. © 2015 American
Propensity score analysis of recurrence for neutrophil-to-lymphocyte ratio in colorectal cancer.
Balde, Alpha I; Fang, Suzhen; He, Linyun; Cai, Zhai; Han, Shuai; Wang, Weiwei; Li, Zhou; Kang, Liang
2017-11-01
The perioperative serum neutrophil-to-lymphocyte ratio (NLR) has been proposed to predict adverse prognosis in colorectal cancer (CRC). However, its interpretation remains unclear. The present study aimed to clarify the prognostic value of NLR in predicting survival among CRC patients. A single-centre, retrospective, propensity score-matched study of adenocarcinoma patients who underwent D3 lymphadenectomy via laparoscopic or open surgery between 2010 and 2016 was conducted. A cutoff of 3.5 was used based on the receiver operating characteristic curve. To overcome selection biases, we performed a 1:1 match using six covariates. The high-preoperative NLR group had a higher recurrence rate than the low group (P < 0.001). Univariate analysis showed that increased NLR (P < 0.001), N1 (P = 0.016), and N2 (P < 0.001) were associated with worse recurrence-free survival (RFS). Multivariate analysis showed that N2 (hazard ratio [HR], 2.492; P = 0.008) was an adverse prognostic factor for RFS. Univariate analysis for overall survival (OS) revealed that high perioperative NLR (P = 0.001), N1 (P = 0.01), N2 (P < 0.001), and distant metastasis (P < 0.001) were adverse prognostic factors. Subsequent multivariate analysis showed that M1 (HR, 3.973; P < 0.001) and N2 (HR, 2.381; P = 0.013) were highly adverse factors for OS. Clinical assessments performed during a 21.14 (±16.20)-mo follow-up revealed that OS (P = 0.001) and RFS (P < 0.001) were worse in the high-perioperative group than in the low group between the matched groups. An elevated preoperative NLR is a strong predictor of worse RFS and OS in CRC patients. Copyright © 2017 Elsevier Inc. All rights reserved.
Leidner, Andrew J.
2014-01-01
This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household's decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research. PMID:25349622
Kulkarni, Girish S; Hermanns, Thomas; Wei, Yanliang; Bhindi, Bimal; Satkunasivam, Raj; Athanasopoulos, Paul; Bostrom, Peter J; Kuk, Cynthia; Li, Kathy; Templeton, Arnoud J; Sridhar, Srikala S; van der Kwast, Theodorus H; Chung, Peter; Bristow, Robert G; Milosevic, Michael; Warde, Padraig; Fleshner, Neil E; Jewett, Michael A S; Bashir, Shaheena; Zlotta, Alexandre R
2017-07-10
Purpose Multidisciplinary management improves complex treatment decision making in cancer care, but its impact for bladder cancer (BC) has not been documented. Although radical cystectomy (RC) currently is viewed as the standard of care for muscle-invasive bladder cancer (MIBC), radiotherapy-based, bladder-sparing trimodal therapy (TMT) that combines transurethral resection of bladder tumor, chemotherapy for radiation sensitization, and external beam radiotherapy has emerged as a valid treatment option. In the absence of randomized studies, this study compared the oncologic outcomes between patients treated with RC or TMT by using a propensity score matched-cohort analysis. Methods Data from patients treated in a multidisciplinary bladder cancer clinic (MDBCC) from 2008 to 2013 were reviewed retrospectively. Those who received TMT for MIBC were identified and matched (for sex, cT and cN stage, Eastern Cooperative Oncology Group status, Charlson comorbidity score, treatment date, age, carcinoma in situ status, and hydronephrosis) with propensity scores to patients who underwent RC. Overall survival and disease-specific survival (DSS) were assessed with Cox proportional hazards modeling and a competing risk analysis, respectively. Results A total of 112 patients with MIBC were included after matching (56 who had been treated with TMT, and 56 who underwent RC). The median age was 68.0 years, and 29.5% had stage cT3/cT4 disease. At a median follow-up of 4.51 years, there were 20 deaths (35.7%) in the RC group (13 as a result of BC) and 22 deaths (39.3%) in the TMT group (13 as a result of BC). The 5-year DSS rate was 73.2% and 76.6% in the RC and TMT groups, respectively ( P = .49). Salvage cystectomy was performed in 6 (10.7%) of 56 patients who received TMT. Conclusion In the setting of a MDBCC, TMT yielded survival outcomes similar to those of matched patients who underwent RC. Appropriately selected patients with MIBC should be offered the opportunity to discuss
J Cerqueira, Rui; Melo, Renata; Moreira, Soraia; A Saraiva, Francisca; Andrade, Marta; Salgueiro, Elson; Almeida, Jorge; J Amorim, Mário; Pinho, Paulo; Lourenço, André; F Leite-Moreira, Adelino
2017-01-01
To compare stentless Freedom Solo and stented Trifecta aortic bioprostheses regarding hemodynamic profile, left ventricular mass regression, early and late postoperative outcomes and survival. Longitudinal cohort study of consecutive patients undergoing aortic valve replacement (from 2009 to 2016) with either Freedom Solo or Trifecta at one centre. Local databases and national records were queried. Postoperative echocardiography (3-6 months) was obtained for hemodynamic profile (mean transprosthetic gradient and effective orifice area) and left ventricle mass determination. After propensity score matching (21 covariates), Kaplan-Meier analysis and cumulative incidence analysis were performed for survival and combined outcome of structural valve deterioration and endocarditis, respectively. Hemodynamics and left ventricle mass regression were assessed by a mixed- -effects model including propensity score as a covariate. From a total sample of 397 Freedom Solo and 525 Trifecta patients with a median follow-up time of 4.0 (2.2- 6.0) and 2.4 (1.4-3.7) years, respectively, a matched sample of 329 pairs was obtained. Well-balanced matched groups showed no difference in survival (hazard ratio=1.04, 95% confidence interval=0.69-1.56) or cumulative hazards of combined outcome (subhazard ratio=0.54, 95% confidence interval=0.21-1.39). Although Trifecta showed improved hemodynamic profile compared to Freedom Solo, no differences were found in left ventricle mass regression. Trifecta has a slightly improved hemodynamic profile compared to Freedom Solo but this does not translate into differences in the extent of mass regression, postoperative outcomes or survival, which were good and comparable for both bioprostheses. Long-term follow-up is needed for comparisons with older models of bioprostheses.
Mauriello, Claudio; Chouillard, Elie; d'alessandro, Antonio; Marte, Gianpaolo; Papadimitriou, Argyri; Chahine, Elias; Kassir, Radwan
2018-04-16
Evaluate the efficacy of single-port sleeve gastrectomy (SPSG) and then compare it to a less-invasive sleeve approach (three-port) (3PSG) according to a propensity score (PS) matching analysis. We analyzed all patients who underwent SG through a three-port or a single-port laparoscopic approach. After 2 years, the follow-up was completed in 84% patients treated with 3PSG and 95% patients of the SPSG group. Excess weight loss (EWL) was comparable for the first year of follow-up within the two groups except for the controls at 3 months in which the SPSG group showed a higher EWL (p = 0.0243). We demonstrated the efficacy of SPSG in bariatric surgery even compared to another, less invasive, laparoscopic SG approach (three-port).
Chiu, Maria; Rezai, Mohammad-Reza; Maclagan, Laura C; Austin, Peter C; Shah, Baiju R; Redelmeier, Donald A; Tu, Jack V
2016-06-01
The impact of moving to a neighborhood more conducive to utilitarian walking on the risk of incident hypertension is uncertain. Our study aimed to examine the effect of moving to a highly walkable neighborhood on the risk of incident hypertension. A population-based propensity-score matched cohort study design was used based on the Ontario population from the Canadian Community Health Survey (2001-2010). Participants were adults ≥ 20 years of age who moved from a low-walkability neighborhood (defined as any neighborhood with a Walk Score < 90) to either a high- (Walk Score ≥ 90) or another low-walkability neighborhood. The incidence of hypertension was assessed by linking the cohort to administrative health databases using a validated algorithm. Propensity-score matched Cox proportional hazard models were used. Annual health examination was used as a control event. Among the 1,057 propensity-score matched pairs there was a significantly lower risk of incident hypertension in the low to high vs. the low to low-walkability groups [hazard ratio = 0.46; 95% CI, 0.26, 0.81, p < 0.01]. The crude hypertension incidence rates were 18.0 per 1,000 person-years (95% CI: 11.6, 24.8) among the low- to low-walkability movers compared with 8.6 per 1,000 person-years (95% CI: 5.3, 12.7) among the low- to high-walkability movers (p < 0.001). There were no significant differences in the hazard of annual health examination between the two mover groups. Moving to a highly walkable neighborhood was associated with a significantly lower risk of incident hypertension. Future research should assess whether specific attributes of walkable neighborhoods (e.g., amenities, density, land-use mix) may be driving this relationship. Chiu M, Rezai MR, Maclagan LC, Austin PC, Shah BR, Redelmeier DA, Tu JV. 2016. Moving to a highly walkable neighborhood and incidence of hypertension: a propensity-score matched cohort study. Environ Health Perspect 124:754-760; http://dx.doi.org/10.1289/ehp
2012-01-01
Background Impact of minimized extracorporeal circulation (MECC) for coronary surgery on mortality remains controversial and gender significantly influence outcome. Methods We analyzed 3,139 male patients undergoing elective coronary surgery between 01/2004 and 05/2009. Using propensity score matching after binary logistic regression, 1,005 patients (from 1,119 patients) undergoing surgery with MECC could be matched with 1,005 patients (from 2,020 patients) undergoing surgery with conventional extracorporeal circulation (CECC). Primary outcome was 30-day mortality. Results Unadjusted 30-day mortality was 2.7% in patients with CECC and 0.8% in those with MECC (mean difference -1.9%; p < 0.001). The adjusted mean difference (average treatment effect of the treated) after matching was -1.5% (95% confidence interval (CI) -2.6 to -0.4; p = 0.006). Postoperative hospital stay was shorter in patients operated with minimized systems (adjusted mean difference -0.8 days; 95% CI -1.46 to -0.09; p = 0.03) and incidence of postoperative neurocognitive dysfunction was also lower (adjusted mean difference -1.3%; 95% CI -2.2 to -0.4; p = 0.001). Chest tube drainage (adjusted mean difference +22 mL; 95% CI -47 to 91; p = 0.5) and risk for acute kidney injury, kidney injury and failure according to RIFLE criteria (adjusted mean difference -1.0%; 95% CI -2.5 to 0.6; p = 0.24) proved to be insignificant between both groups. Apart from reduced 30-day mortality, however, average treatment effects for intensive care unit stay, postoperative hospital stay, chest tube drainage and kidney injury did not significantly differ. Conclusion Using propensity score analysis, we observed an association between MECC and reduced 30-day mortality in men, but our results call for further analysis. PMID:22424497
Mak, Kwok-Kei; Kim, Dae-Hwan; Leigh, J Paul
2015-01-01
Few population-based studies have used an econometric approach to understand the association between two cancer risk factors, obesity and stress. This study investigated sociodemographic differences in the association between obesity and stress among Korean adults (6,546 men and 8,473 women). Data were drawn from the Korean National Health and Nutrition Examination Survey for 2008, 2009, and 2010. Ordered logistic regression models and propensity score matching methods were used to examine the associations between obesity and stress, stratified by gender and age groups. In women, the stress level of the obese group was found to be 27.6% higher than the nonobese group in the ordered logistic regression; the obesity effect on stress was statistically significant in the propensity score-matched analysis. Corresponding evidence for the effect of obesity on stress was lacking among men. Participants who were young, well-educated, and working were more likely to report stress. In Korea, obesity causes stress in women but not in men. Young women are susceptible to a disproportionate level of stress. More cancer prevention programs targeting young and obese women are encouraged in developed Asian countries.
Zhang, Zhongheng; Ni, Hongying; Xu, Xiao
2014-08-01
Propensity score (PS) analysis has been increasingly used in critical care medicine; however, its validation has not been systematically investigated. The present study aimed to compare effect sizes in PS-based observational studies vs. randomized controlled trials (RCTs) (or meta-analysis of RCTs). Critical care observational studies using PS were systematically searched in PubMed from inception to April 2013. Identified PS-based studies were matched to one or more RCTs in terms of population, intervention, comparison, and outcome. The effect sizes of experimental treatments were compared for PS-based studies vs. RCTs (or meta-analysis of RCTs) with sign test. Furthermore, ratio of odds ratio (ROR) was calculated from the interaction term of treatment × study type in a logistic regression model. A ROR < 1 indicates greater benefit for experimental treatment in RCTs compared with PS-based studies. RORs of each comparison were pooled by using meta-analytic approach with random-effects model. A total of 20 PS-based studies were identified and matched to RCTs. Twelve of the 20 comparisons showed greater beneficial effect for experimental treatment in RCTs than that in PS-based studies (sign test P = 0.503). The difference was statistically significant in four comparisons. ROR can be calculated from 13 comparisons, of which four showed significantly greater beneficial effect for experimental treatment in RCTs. The pooled ROR was 0.71 (95% CI: 0.63, 0.79; P = 0.002), suggesting that RCTs (or meta-analysis of RCTs) were more likely to report beneficial effect for the experimental treatment than PS-based studies. The result remained unchanged in sensitivity analysis and meta-regression. In critical care literature, PS-based observational study is likely to report less beneficial effect of experimental treatment compared with RCTs (or meta-analysis of RCTs). Copyright © 2014 Elsevier Inc. All rights reserved.
Ratti, Francesca; Catena, Marco; Di Palo, Saverio; Staudacher, Carlo; Aldrighetti, Luca
2016-11-01
Thanks to widespread diffusion of minimally invasive approach in the setting of both colorectal and hepatic surgeries, the interest in combined resections for colorectal cancer and synchronous liver metastases (SCLM) by totally laparoscopic approach (TLA) has increased. Aim of this study was to compare outcome of combined resections for SCLM performed by TLA or by open approach, in a propensity-score-based study. All 25 patients undergoing combined TLA for SCLM at San Raffaele Hospital in Milano were compared in a case-matched analysis with 25 out of 91 patients undergoing totally open approach (TOA group). Groups were matched with 1:2 ratio using propensity scores based on covariates representing disease severity. Main endpoints were postoperative morbidity and long-term outcome. The Modified Accordion Severity Grading System was used to quantify complications. The groups resulted comparable in terms of patients and disease characteristics. The TLA group, as compared to the TOA group, had lower blood loss (350 vs 600 mL), shorter postoperative stay (9 vs 12 days), lower postoperative morbidity index (0.14 vs 0.20) and severity score for complicated patients (0.60 vs 0.85). Colonic anastomosis leakage had the highest fractional complication burden in both groups. In spite of comparable long-term overall survival, the TLA group had better recurrence-free survival. TLA for combined resections is feasible, and its indications can be widened to encompass a larger population of patients, provided its benefits in terms of reduced overall risk and severity of complications, rapid functional recovery and favorable long-term outcomes.
Hoshino, Masato; Omura, Nobuo; Yano, Fumiaki; Tsuboi, Kazuto; Yamamoto, Se Ryung; Akimoto, Shunsuke; Masuda, Takahiro; Kashiwagi, Hideyuki; Yanaga, Katsuhiko
2018-02-01
In the present study, we examined how the body mass index (BMI) affected the outcomes of laparoscopic fundoplication for GERD in patients, whose backgrounds were matched in a propensity score-matched analysis. We divided the patients into two groups (BMI <25 kg/m 2 and BMI ≥25 kg/m 2 ). The following background information was matched for the propensity score-matched analysis: sex, age, degree of esophageal hiatal hernia, acid exposure time, and degree of reflux esophagitis. In total, 105 subjects were extracted in each group. The surgical outcomes and postoperative outcomes of patients with BMI <25 kg/m 2 (Group A) and those with BMI ≥25 kg/m 2 (Group B) were compared and examined. There were no differences in the surgical procedure, intraoperative complications, or estimated blood loss (p = 0.876, p = 0.516, p = 0.438, respectively); however, the operative time was significantly prolonged in Group B (p = 0.003). The rate of postoperative recurrence in Group A was 17% (15/87 patients), while that in Group B was 11% (12/91 patients), and did not differ to a statistically significant extent (p = 0.533). Although the operative time for GERD in obese patients was prolonged in comparison with non-obese patients, there was no difference in the rate of postoperative recurrence.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Akinwande, Olaguoke K., E-mail: gokeakin@gmail.com; Philips, Prejesh, E-mail: prejesh.philips@louisville.edu; Duras, Petr, E-mail: durasp@seznam.cz
2015-04-15
PurposeTo compare the feasibility, safety, and efficacy with small and large irinotecan drug-eluting beads (DEBIRI) for treating hepatic colorectal metastases.MethodsUsing our prospectively maintained, multi-center, intra-arterial therapy registry, we identified 196 patients treated with a combination of large beads (100–300 to 500–700 μm) and patients treated with a combination of small beads (70–150 to 100–300 μm). To minimize selection bias, a propensity score analysis was performed to compare both groups.ResultsUnadjusted analysis consisted of 196 and 30 patients treated with large and small beads, respectively. The adjusted analysis consisted of 19 patients each. Unadjusted analysis showed decreased all-grade (p = <0.001) and high-grade adverse effects (p = 0.02)more » in the small bead group, with a persisting trend toward decreased overall side effects in the adjusted analysis favoring small beads (p = 0.09) The adjusted analysis showed the percentage dose delivered (delivered dose/intended dose) was significantly greater in the small bead group compared to the large bead group (96 vs 79 %; p = 0.005). There were also a lower percentage of treatments terminating in complete stasis in the adjusted analysis (0.0035). Adjusted analysis also showed increased objective response rate (ORR) at 12 months (p = 0.04), with a corresponding trend also seen in the unadjusted analysis (0.09).ConclusionSmaller beads result in increased dose delivery probably due to less propensity to reach complete stasis. It may also lead to more durable long-term efficacy. Smaller beads also demonstrate similarly low toxicity compared to large-sized beads with a trend toward less toxicity.« less
Pingault, Jean Baptiste; Côté, Sylvana M; Petitclerc, Amélie; Vitaro, Frank; Tremblay, Richard E
2015-01-01
Parental educational expectations have been associated with children's educational attainment in a number of long-term longitudinal studies, but whether this relationship is causal has long been debated. The aims of this prospective study were twofold: 1) test whether low maternal educational expectations contributed to failure to graduate from high school; and 2) compare the results obtained using different strategies for accounting for confounding variables (i.e. multivariate regression and propensity score matching). The study sample included 1,279 participants from the Quebec Longitudinal Study of Kindergarten Children. Maternal educational expectations were assessed when the participants were aged 12 years. High school graduation—measuring educational attainment—was determined through the Quebec Ministry of Education when the participants were aged 22-23 years. Findings show that when using the most common statistical approach (i.e. multivariate regressions to adjust for a restricted set of potential confounders) the contribution of low maternal educational expectations to failure to graduate from high school was statistically significant. However, when using propensity score matching, the contribution of maternal expectations was reduced and remained statistically significant only for males. The results of this study are consistent with the possibility that the contribution of parental expectations to educational attainment is overestimated in the available literature. This may be explained by the use of a restricted range of potential confounding variables as well as the dearth of studies using appropriate statistical techniques and study designs in order to minimize confounding. Each of these techniques and designs, including propensity score matching, has its strengths and limitations: A more comprehensive understanding of the causal role of parental expectations will stem from a convergence of findings from studies using different techniques and
Best (but oft-forgotten) practices: propensity score methods in clinical nutrition research.
Ali, M Sanni; Groenwold, Rolf Hh; Klungel, Olaf H
2016-08-01
In observational studies, treatment assignment is a nonrandom process and treatment groups may not be comparable in their baseline characteristics, a phenomenon known as confounding. Propensity score (PS) methods can be used to achieve comparability of treated and nontreated groups in terms of their observed covariates and, as such, control for confounding in estimating treatment effects. In this article, we provide a step-by-step guidance on how to use PS methods. For illustrative purposes, we used simulated data based on an observational study of the relation between oral nutritional supplementation and hospital length of stay. We focused on the key aspects of PS analysis, including covariate selection, PS estimation, covariate balance assessment, treatment effect estimation, and reporting. PS matching, stratification, covariate adjustment, and weighting are discussed. R codes and example data are provided to show the different steps in a PS analysis. © 2016 American Society for Nutrition.
Combining Propensity Score Methods and Complex Survey Data to Estimate Population Treatment Effects
ERIC Educational Resources Information Center
Stuart, Elizabeth A.; Dong, Nianbo; Lenis, David
2016-01-01
Complex surveys are often used to estimate causal effects regarding the effects of interventions or exposures of interest. Propensity scores (Rosenbaum & Rubin, 1983) have emerged as one popular and effective tool for causal inference in non-experimental studies, as they can help ensure that groups being compared are similar with respect to a…
Selection and Socialization Effects in Early Adolescent Alcohol Use: A Propensity Score Analysis
Scalco, Matthew D.; Trucco, Elisa M.; Coffman, Donna L.; Colder, Craig R.
2015-01-01
The robust correlation between peer and adolescent alcohol use (AU) has been taken as evidence for both socialization and selection processes in the etiology of adolescent AU. Accumulating evidence from studies using a diverse range of methodological and statistical approaches suggests that both processes are involved. A major challenge in testing whether peer AU predicts an adolescent's drinking (socialization) or whether an adolescent's drinking predicts peer AU (selection) is the myriad of potentially confounding factors that might lead to an overestimation of socialization and selection effects. After creating AU transition groups based on peer and adolescent AU across two waves (N = 765; age = 10-15; 53% female), we test whether transitions into AU by adolescents and peers predict later peer and adolescent AU respectively, using (1) propensity score analysis to balance transition groups on 26 potential confounds, (2) a longitudinal design with three waves to establish temporal precedence, and (3) both adolescent (target) and peer self-report of peer AU to disentangle effects attributable to shared reporter bias. Both selection and socialization were supported using both peer self-report of AU and adolescent-report of peer AU. Although cross-sectional analyses suggested peer self-reported models were associated with smaller effects than perceived peer AU, longitudinal analyses suggest a similar sized effect across reporter of peer AU for both selection and socialization. The implications of these findings for the etiology and treatment of adolescent AU are discussed. PMID:25601099
McLawhorn, Alexander S; Fu, Michael C; Schairer, William W; Sculco, Peter K; MacLean, Catherine H; Padgett, Douglas E
2017-09-01
Discharge destination, either home or skilled care facility, after total knee arthroplasty (TKA) may be associated with significant variation in postacute care outcomes. The purpose of this study was to characterize the 30-day postdischarge outcomes after primary TKA relative to discharge destination. All primary unilateral TKAs performed for osteoarthritis from 2011-2014 were identified in the National Surgical Quality Improvement Program database. Propensity scores based on predischarge characteristics were used to adjust for selection bias in discharge destination. Propensity-adjusted multivariable logistic regressions were used to examine associations between discharge destination and postdischarge complications. Among 101,256 primary TKAs identified, 70,628 were discharged home and 30,628 to skilled care facilities. Patients discharged to facilities were more frequently were female, older, higher body mass index class, higher Charlson comorbidity index and American Society of Anesthesiologists scores, had predischarge complications, received general anesthesia, and classified as nonindependent preoperatively. Propensity adjustment accounted for this selection bias. Patients discharged to skilled care facilities after TKA had higher odds of any major complication (odds ratio = 1.25; 95% confidence interval, 1.13-1.37) and readmission (odds ratio = 1.81; 95% confidence interval, 1.50-2.18). Skilled care was associated with increased odds for respiratory, septic, thromboembolic, and urinary complications. Associations with death, cardiac, and wound complications were not significant. After controlling for predischarge characteristics, discharge to skilled care facilities vs home after primary TKA is associated with higher odds of numerous complications and unplanned readmission. These results support coordination of care pathways to facilitate home discharge after hospitalization for TKA whenever possible. Copyright © 2017 Elsevier Inc. All rights reserved.
2014-01-01
Background We estimate the effect of antibiotics given in the intrapartum period on early-onset neonatal sepsis in Dhaka, Bangladesh using propensity score techniques. Methods We followed 600 mother-newborn pairs as part of a cohort study at a maternity center in Dhaka. Some pregnant women received one dose of intravenous antibiotics during labor based on clinician discretion. Newborns were followed over the first seven days of life for early-onset neonatal sepsis defined by a modified version of the World Health Organization Young Infants Integrated Management of Childhood Illnesses criteria. Using propensity scores we matched women who received antibiotics with similar women who did not. A final logistic regression model predicting sepsis was run in the matched sample controlling for additional potential confounders. Results Of the 600 mother-newborn pairs, 48 mothers (8.0%) received antibiotics during the intrapartum period. Seventy-seven newborns (12.8%) were classified with early-onset neonatal sepsis. Antibiotics appeared to be protective (odds ratio 0.381, 95% confidence interval 0.115–1.258), however this was not statistically significant. The results were similar after adjusting for prematurity, wealth status, and maternal colonization status (odds ratio 0.361, 95% confidence interval 0.106–1.225). Conclusions Antibiotics administered during the intrapartum period may reduce the risk of early-onset neonatal sepsis in high neonatal mortality settings like Dhaka. PMID:24742087
Molina, J; Sued, M; Valdora, M
2018-06-05
Generalized linear models are often assumed to fit propensity scores, which are used to compute inverse probability weighted (IPW) estimators. To derive the asymptotic properties of IPW estimators, the propensity score is supposed to be bounded away from zero. This condition is known in the literature as strict positivity (or positivity assumption), and, in practice, when it does not hold, IPW estimators are very unstable and have a large variability. Although strict positivity is often assumed, it is not upheld when some of the covariates are unbounded. In real data sets, a data-generating process that violates the positivity assumption may lead to wrong inference because of the inaccuracy in the estimations. In this work, we attempt to conciliate between the strict positivity condition and the theory of generalized linear models by incorporating an extra parameter, which results in an explicit lower bound for the propensity score. An additional parameter is added to fulfil the overlap assumption in the causal framework. Copyright © 2018 John Wiley & Sons, Ltd.
Hendryx, Michael; Luo, Juhua
2015-01-01
Previous research on public health consequences of mountaintop removal (MTR) coal mining has been limited by the observational nature of the data. The current study used propensity scores, a method designed to overcome this limitation, to draw more confident causal inferences about mining effects on respiratory health using non-experimental data. These data come from a health survey of 682 adults residing in two rural areas of Virginia, USA characterized by the presence or absence of MTR mining. Persons with a history of occupational exposure as coal miners were excluded. Nine covariates including age, sex, current and former smoking, overweight, obesity, high school education, college education, and exposure to coal as a home-heating source were selected to estimate propensity scores. Propensity scores were tested for balance and then used as weights to create quasi-experimental exposed and unexposed groups. Results indicated that persons in the mountaintop mining group had significantly (p < 0.0001) elevated prevalence of respiratory symptoms and chronic obstructive pulmonary disease. The results suggest that impaired respiratory health results from exposure to MTR environments and not from other risks.
Chen, Shuaishuai; Yan, Haixi; Du, Juping; Li, Jun; Shen, Bo; Ying, Haijian; Zhang, Ying; Chen, Shiyong
2018-07-01
Nutrition and coagulation play important roles in cancer progression. This study was aimed to investigate the value of the albumin/fibrinogen ratio (AFR) in non-small cell lung cancer (NSCLC) patients, through a propensity score matching (PSM) method. We retrospectively analyzed 529 NSCLC patients underwent surgical resection from 2010 to 2015. PSM was used to eliminate possible biases. A Cox proportional hazards regression model was performed to evaluate the prognostic value of AFR in NSCLC. The optimal value was 9.67 for the AFR by ROC (receiver operating characteristic) curve. The AFR was statistically significantly associated with age, sex, smoking history, histological subtype, tumor size, pathological stage and adjuvant therapy (p < 0.05). Multivariate analysis indicated that the pathological stage and pre-resection AFR were independent prognostic factors for patients with NSCLC. Additionally, elevated AFR indicated a better outcome, and patients with higher AFR had lower risk for overall death (OS) (HR 0.512, 95% CI 0.316-0.829, p = 0.006) as well as disease-free death (DFS) (HR 0.561, 95% CI 0.399-0.787, p = 0.001). The propensity score model identified 120 patients from each group that were balanced for age, sex, smoking history, histological subtype, tumor size, stage distribution and adjuvant therapy. In multivariable regression analysis of PSM groups, the result indicated that the AFR was predictive for OS (HR 0.392, 95% CI 0.225-0.683, p < 0.001) and DFS (HR 0.526, 95% CI 0.344-0.805, p = 0.003). Pre-resection AFR can be considered as an independent prognostic factor in NSCLC patients, and higher AFR may enhance OS and DFS of NSCLC patients. Copyright © 2018 Elsevier B.V. All rights reserved.
Stukel, Thérèse A.; Fisher, Elliott S; Wennberg, David E.; Alter, David A.; Gottlieb, Daniel J.; Vermeulen, Marian J.
2007-01-01
Context Comparisons of outcomes between patients treated and untreated in observational studies may be biased due to differences in patient prognosis between groups, often because of unobserved treatment selection biases. Objective To compare 4 analytic methods for removing the effects of selection bias in observational studies: multivariable model risk adjustment, propensity score risk adjustment, propensity-based matching, and instrumental variable analysis. Design, Setting, and Patients A national cohort of 122 124 patients who were elderly (aged 65–84 years), receiving Medicare, and hospitalized with acute myocardial infarction (AMI) in 1994–1995, and who were eligible for cardiac catheterization. Baseline chart reviews were taken from the Cooperative Cardiovascular Project and linked to Medicare health administrative data to provide a rich set of prognostic variables. Patients were followed up for 7 years through December 31, 2001, to assess the association between long-term survival and cardiac catheterization within 30 days of hospital admission. Main Outcome Measure Risk-adjusted relative mortality rate using each of the analytic methods. Results Patients who received cardiac catheterization (n=73 238) were younger and had lower AMI severity than those who did not. After adjustment for prognostic factors by using standard statistical risk-adjustment methods, cardiac catheterization was associated with a 50% relative decrease in mortality (for multivariable model risk adjustment: adjusted relative risk [RR], 0.51; 95% confidence interval [CI], 0.50–0.52; for propensity score risk adjustment: adjusted RR, 0.54; 95% CI, 0.53–0.55; and for propensity-based matching: adjusted RR, 0.54; 95% CI, 0.52–0.56). Using regional catheterization rate as an instrument, instrumental variable analysis showed a 16% relative decrease in mortality (adjusted RR, 0.84; 95% CI, 0.79–0.90). The survival benefits of routine invasive care from randomized clinical trials
Song, Minju; Kang, Minji; Kang, Dae Ryong; Jung, Hoi In; Kim, Euiseong
2018-05-01
The purpose of this retrospective clinical study was to evaluate the effect of lesion types related to endodontic microsurgery on the clinical outcome. Patients who underwent endodontic microsurgery between March 2001 and March 2014 with a postoperative follow-up period of at least 1 year were included in the study. Survival analyses were conducted to compare the clinical outcomes between isolated endodontic lesion group (endo group) and endodontic-periodontal combined lesion group (endo-perio group) and to evaluate other clinical variables. To reduce the effect of selection bias in this study, the estimated propensity scores were used to match the cases of the endo group with those of the endo-perio group. Among the 414 eligible cases, the 83 cases in the endo-perio group were matched to 166 out of the 331 cases in the endo group based on propensity score matching (PSM). The cumulated success rates of the endo and endo-perio groups were 87.3 and 72.3%, respectively. The median success period of the endo-perio group was 12 years (95% CI: 5.507, 18.498). Lesion type was found to be significant according to both Log-rank test (P = 0.002) and Cox proportional hazard regression analysis (P = 0.001). Among the other clinical variables, sex (female or male), age, and tooth type (anterior, premolar, or molar) were determined to be significant in Cox regression analysis (P < 0.05). Endodontic-periodontal combined lesions had a negative effect on the clinical outcome based on an analysis that utilized PSM, a useful statistical matching method for observational studies. Lesion type is a significant predictor of the outcome of endodontic microsurgery.
2012-01-01
Introduction Endotracheal intubation in the ICU is associated with a high incidence of complications. Etomidate use is debated in septic shock because it increases the risk of critical illness-related corticosteroid insufficiency, which may impact outcome. We hypothesized that hydrocortisone, administered in all septic shock cases in our ICU, may counteract some negative effects of etomidate. The aim of our study was to compare septic shock patients who received etomidate versus another induction drug both for short-term safety and for long-term outcomes. Methods A single-center observational study was carried out in septic shock patients, treated with hydrocortisone and intubated within the first 48 hours of septic shock. Co-primary end points were life-threatening complications incidence occurring within the first hour after intubation and mortality during the ICU stay. Statistical analyses included unmatched and matched cohorts using a propensity score analysis. P < 0.05 was considered significant. Results Sixty patients in the etomidate cohort and 42 patients in the non-etomidate cohort were included. Critical illness-related corticosteroid insufficiency was 79% in the etomidate cohort and 52% in the non-etomidate cohort (P = 0.01). After intubation, life-threatening complications occurred in 36% of the patients whatever the cohort. After adjustment with propensity score analysis, etomidate was a protective factor for death in the ICU both in unmatched (hazard ratio, 0.33 (0.15 to 0.75); P < 0.01)) and matched cohorts (hazard ratio, 0.33 (0.112 to 0.988); P = 0.04). Conclusion In septic shock patients treated with hydrocortisone, etomidate did not decrease life-threatening complications following intubation, but when associated with hydrocortisone it also did not impair outcome. PMID:23171852
Levofloxacin versus azithromycin for treating legionella pneumonia: a propensity score analysis.
Garcia-Vidal, C; Sanchez-Rodriguez, I; Simonetti, A F; Burgos, J; Viasus, D; Martin, M T; Falco, V; Carratalà, J
2017-09-01
Concerns have arisen regarding the equivalence of levofloxacin and some macrolides for treating community-acquired legionella pneumonia (LP). We aimed to compare the outcomes of current patients with LP treated with levofloxacin, azithromycin and clarithromycin. Observational retrospective multicentre study of consecutive patients with LP requiring hospitalization (2000-2014) conducted in two hospitals. The primary outcome assessed was 30-day mortality. To control for confounding, therapy was assessed by multivariate analysis. We documented 446 patients with LP, of which 175 were treated with levofloxacin, 177 with azithromycin and 58 with clarithromycin. No significant differences in time to defervescence (2 (interquartile range (IQR) 1-4) versus 2 (IQR 1-3) days; p 0.453), time to achieve clinical stability (3 (2-5) versus 3 (2-5) days; p 0.486), length of intravenous therapy (3 (2-5.25) versus 4 (3-6) days; p 0.058) and length of hospital stay (7 (5-10) versus 6 (5-9) days; p 0.088) were found between patients treated with levofloxacin and those treated with azithromycin. Patients treated with clarithromycin had longer intravenous antibiotic treatment (3 (2-5.25) versus 5 (3-6.25) days; p 0.002) and longer hospital stay (7 (5-10) versus 9 (7-14) days; p 0.043) compared with those treated with levofloxacin. The overall mortality was 4.3% (19 patients). Neither univariate nor multivariate analysis showed a significant association of levofloxacin versus azithromycin on mortality (4 (2.3%) versus 9 (5.1%) deaths; p 0.164). The results did not change after incorporation of the propensity score into the models. In our study, no significant differences in most outcomes were found between patients treated with levofloxacin and those treated with azithromycin. Due to the small number of deaths, results regarding mortality should be interpreted with caution. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All
The effects of breastfeeding on childhood BMI: a propensity score matching approach.
Gibson, Laura A; Hernández Alava, Mónica; Kelly, Michael P; Campbell, Michael J
2017-12-01
Many studies have found a statistical association between breastfeeding and childhood adiposity. This paper investigates whether breastfeeding has an effect on subsequent childhood body mass index (BMI) using propensity scores to account for confounding. We use data from the Millennium Cohort Study, a nationally representative UK cohort survey, which contains detailed information on infant feeding and childhood BMI. Propensity score matching is used to investigate the mean BMI in children breastfed exclusively and partially for different durations of time. We find statistically significant influences of breastfeeding on childhood BMI, particularly in older children, when breastfeeding is prolonged and exclusive. At 7 years, children who were exclusively breastfed for 16 weeks had a BMI 0.28 kg/m2 (95% confidence interval 0.07 to 0.49) lower than those who were never breastfed, a 2% reduction from the mean BMI of 16.6 kg/m2. For this young cohort, even small effects of breastfeeding on BMI could be important. In order to reduce BMI, breastfeeding should be encouraged as part of wider lifestyle intervention. This evidence could help to inform public health bodies when creating public health guidelines and recommendations. © The Author 2016. Published by Oxford University Press on behalf of Faculty of Public Health.
Shin, Ju-Young; Choi, Nam-Kyong; Lee, Joongyub; Park, Mi-Ju; Lee, Shin Haeng; Park, Byung-Joo
2015-08-01
With an increase in antipsychotic use in the elderly, the safety profile of antipsychotics has been emphasized. Strong concerns have been raised about whether the risk of ischemic stroke differs between risperidone and haloperidol. This study compared the risk of ischemic stroke between elderly patients taking risperidone and haloperidol. We conducted a retrospective cohort study using the Korea Health Insurance Review and Assessment Service database, applying a propensity-matched analysis. The cohort consisted of elderly patients who were newly prescribed haloperidol or risperidone between January 1, 2006 and December 31, 2009. Patients with prior cerebrovascular diseases (ICD-10, I60-I69), transient ischemic attack (ICD-10, G45), or cerebral tumors (ICD-10, C31) during 365 days prior to the initiation date were excluded. The study subjects were selected by propensity score matching. The outcome was defined as the first hospitalization for ischemic stroke (ICD-10, I63). Cox regression models were used to estimate the hazard ratio (HR) and 95% confidence intervals (95% CI) for ischemic stroke with haloperidol compared with risperidone use. A total of 14,103 patients were included in the propensity-matched cohort for each drug. Overall, the incidence rate was higher for haloperidol users compared to the risperidone users (6.43 per 1000 person-years vs. 2.88 per 1000 person-years). A substantially increased risk was observed in haloperidol users (adjusted HR = 2.02, 95% CI, 1.12-3.62). The evidence showed that haloperidol should be prescribed in the elderly with caution. © The Author(s) 2015.
Pingault, Jean Baptiste; Côté, Sylvana M.; Petitclerc, Amélie; Vitaro, Frank; Tremblay, Richard E.
2015-01-01
Background Parental educational expectations have been associated with children’s educational attainment in a number of long-term longitudinal studies, but whether this relationship is causal has long been debated. The aims of this prospective study were twofold: 1) test whether low maternal educational expectations contributed to failure to graduate from high school; and 2) compare the results obtained using different strategies for accounting for confounding variables (i.e. multivariate regression and propensity score matching). Methodology/Principal Findings The study sample included 1,279 participants from the Quebec Longitudinal Study of Kindergarten Children. Maternal educational expectations were assessed when the participants were aged 12 years. High school graduation – measuring educational attainment – was determined through the Quebec Ministry of Education when the participants were aged 22–23 years. Findings show that when using the most common statistical approach (i.e. multivariate regressions to adjust for a restricted set of potential confounders) the contribution of low maternal educational expectations to failure to graduate from high school was statistically significant. However, when using propensity score matching, the contribution of maternal expectations was reduced and remained statistically significant only for males. Conclusions/Significance The results of this study are consistent with the possibility that the contribution of parental expectations to educational attainment is overestimated in the available literature. This may be explained by the use of a restricted range of potential confounding variables as well as the dearth of studies using appropriate statistical techniques and study designs in order to minimize confounding. Each of these techniques and designs, including propensity score matching, has its strengths and limitations: A more comprehensive understanding of the causal role of parental expectations will stem from
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smith, Graham D.; Pickles, Tom; Crook, Juanita
2015-03-01
Purpose: To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. Methods and Materials: Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2)more » intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups. Results: Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500). Conclusions: Propensity score matched analysis showed that BT
Smith, Graham D; Pickles, Tom; Crook, Juanita; Martin, Andre-Guy; Vigneault, Eric; Cury, Fabio L; Morris, Jim; Catton, Charles; Lukka, Himu; Warner, Andrew; Yang, Ying; Rodrigues, George
2015-03-01
To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2) intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups. Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500). Propensity score matched analysis showed that BT options led to statistically significant improvements in bFFS in
Al-Mazrou, Ahmed M; Baser, Onur; Kiran, Ravi P
2018-06-01
The study aims to evaluate the clinical and financial outcomes of the use of robotic when compared to laparoscopic colorectal surgery and any changes in these over time. From the Premier Perspective database, patients who underwent elective laparoscopic and robotic colorectal resections from 2012 to 2014 were included. Laparoscopic colorectal resections were propensity score matched to robotic cases for patient, disease, procedure, surgeon specialty, and hospital type and volume. The two groups were compared for conversion, hospital stay, 30-day post-discharge readmission, mortality, and complications. Direct, cumulative, and total (including 30-day post-discharge) costs were evaluated. Clinical and financial outcomes were also separately assessed for each of the included years. Of 36,701 patients, 32,783 (89.3%) had laparoscopic colorectal resection and 3918 (10.7%) had robotic colorectal resection; 4438 procedures (2219 in each group) were propensity score matched. For the entire period, conversion to open approach (4.7 vs. 3.7%, p = 0.1) and hospital stay (mean days [SD] 6 [5.3] vs. 5 [4.6], p = 0.2) were comparable between robotic and laparoscopic procedures. Surgical and medical complications were also the same for the two groups. However, the robotic approach was associated with lower readmission (6.3 vs. 4.8%, p = 0.04). Wound or abdominal infection (4.7 vs. 2.3%, p = 0.01) and respiratory complications (7.4 vs. 4.7%, p = 0.02) were significantly lower for the robotic group in the final year of inclusion, 2014. Direct, cumulative, and total (including 30-day post-discharge) costs were significantly higher for robotic surgery. The difference in costs between the two approaches reduced over time (direct cost difference: 2012, $2698 vs. 2013, $2235 vs. 2014, $1402). Robotic colorectal surgery can be performed with comparable clinical outcomes to laparoscopy. With greater use of the technology, some further recovery benefits may be evident
2012-01-01
Background Existing methods for predicting protein solubility on overexpression in Escherichia coli advance performance by using ensemble classifiers such as two-stage support vector machine (SVM) based classifiers and a number of feature types such as physicochemical properties, amino acid and dipeptide composition, accompanied with feature selection. It is desirable to develop a simple and easily interpretable method for predicting protein solubility, compared to existing complex SVM-based methods. Results This study proposes a novel scoring card method (SCM) by using dipeptide composition only to estimate solubility scores of sequences for predicting protein solubility. SCM calculates the propensities of 400 individual dipeptides to be soluble using statistic discrimination between soluble and insoluble proteins of a training data set. Consequently, the propensity scores of all dipeptides are further optimized using an intelligent genetic algorithm. The solubility score of a sequence is determined by the weighted sum of all propensity scores and dipeptide composition. To evaluate SCM by performance comparisons, four data sets with different sizes and variation degrees of experimental conditions were used. The results show that the simple method SCM with interpretable propensities of dipeptides has promising performance, compared with existing SVM-based ensemble methods with a number of feature types. Furthermore, the propensities of dipeptides and solubility scores of sequences can provide insights to protein solubility. For example, the analysis of dipeptide scores shows high propensity of α-helix structure and thermophilic proteins to be soluble. Conclusions The propensities of individual dipeptides to be soluble are varied for proteins under altered experimental conditions. For accurately predicting protein solubility using SCM, it is better to customize the score card of dipeptide propensities by using a training data set under the same specified
Double propensity-score adjustment: A solution to design bias or bias due to incomplete matching.
Austin, Peter C
2017-02-01
Propensity-score matching is frequently used to reduce the effects of confounding when using observational data to estimate the effects of treatments. Matching allows one to estimate the average effect of treatment in the treated. Rosenbaum and Rubin coined the term "bias due to incomplete matching" to describe the bias that can occur when some treated subjects are excluded from the matched sample because no appropriate control subject was available. The presence of incomplete matching raises important questions around the generalizability of estimated treatment effects to the entire population of treated subjects. We describe an analytic solution to address the bias due to incomplete matching. Our method is based on using optimal or nearest neighbor matching, rather than caliper matching (which frequently results in the exclusion of some treated subjects). Within the sample matched on the propensity score, covariate adjustment using the propensity score is then employed to impute missing potential outcomes under lack of treatment for each treated subject. Using Monte Carlo simulations, we found that the proposed method resulted in estimates of treatment effect that were essentially unbiased. This method resulted in decreased bias compared to caliper matching alone and compared to either optimal matching or nearest neighbor matching alone. Caliper matching alone resulted in design bias or bias due to incomplete matching, while optimal matching or nearest neighbor matching alone resulted in bias due to residual confounding. The proposed method also tended to result in estimates with decreased mean squared error compared to when caliper matching was used.
Double propensity-score adjustment: A solution to design bias or bias due to incomplete matching
2016-01-01
Propensity-score matching is frequently used to reduce the effects of confounding when using observational data to estimate the effects of treatments. Matching allows one to estimate the average effect of treatment in the treated. Rosenbaum and Rubin coined the term “bias due to incomplete matching” to describe the bias that can occur when some treated subjects are excluded from the matched sample because no appropriate control subject was available. The presence of incomplete matching raises important questions around the generalizability of estimated treatment effects to the entire population of treated subjects. We describe an analytic solution to address the bias due to incomplete matching. Our method is based on using optimal or nearest neighbor matching, rather than caliper matching (which frequently results in the exclusion of some treated subjects). Within the sample matched on the propensity score, covariate adjustment using the propensity score is then employed to impute missing potential outcomes under lack of treatment for each treated subject. Using Monte Carlo simulations, we found that the proposed method resulted in estimates of treatment effect that were essentially unbiased. This method resulted in decreased bias compared to caliper matching alone and compared to either optimal matching or nearest neighbor matching alone. Caliper matching alone resulted in design bias or bias due to incomplete matching, while optimal matching or nearest neighbor matching alone resulted in bias due to residual confounding. The proposed method also tended to result in estimates with decreased mean squared error compared to when caliper matching was used. PMID:25038071
Okamoto, Miwako; Ishigami, Hideaki; Tokimoto, Kumiko; Matsuoka, Megumi; Tango, Ryoko
2013-08-01
The purpose of this study is to evaluate the effectiveness of a single session intervention designed to reduce emotional distress in first-time mothers. We held a parenting class for first-time mothers who had given birth at a university hospital in Tokyo, Japan. The program of the class consists of lectures on infant care and group discussion, which is a common form of intervention in Japan. The effectiveness of intervention is assessed according to differences in emotional distress experienced by class participants and nonparticipants, and analyzed by the use of a propensity score method to avoid self-selection bias. In order to be more confident about our results, we employ several variations of this method. Results from statistical analysis show that although the effectiveness of the intervention was limited, it was able to alleviate subjects' loss of self-confidence as mothers. Because this outcome shows a good degree of consistency across methods, it can be considered robust. Moreover, it is roughly consistent with previous studies. Effectiveness can probably be increased by developing a program that improves upon the intervention.
Ahrar, Judy U; Gupta, Sanjay; Ensor, Joe E; Mahvash, Armeen; Sabir, Sharjeel H; Steele, Joseph R; McRae, Stephen E; Avritscher, Rony; Huang, Steven Y; Odisio, Bruno C; Murthy, Ravi; Ahrar, Kamran; Wallace, Michael J; Tam, Alda L
2017-02-01
To evaluate the use of a self-expanding tract sealant device (BioSentry™) on the rates of pneumothorax and chest tube insertion after percutaneous lung biopsy. In this retrospective study, we compared 318 patients who received BioSentry™ during percutaneous lung biopsy (treated group) with 1956 patients who did not (control group). Patient-, lesion-, and procedure-specific variables, and pneumothorax and chest tube insertion rates were recorded. To adjust for potential selection bias, patients in the treated group were matched 1:1 to patients in the control group using propensity score matching based on the above-mentioned variables. Patients were considered a match if the absolute difference in their propensity scores was ≤equal to 0.02. Before matching, the pneumothorax and chest tube rates were 24.5 and 13.1% in the control group, and 21.1 and 8.5% in the treated group, respectively. Using propensity scores, a match was found for 317 patients in the treatment group. Chi-square contingency matched pair analysis showed the treated group had significantly lower pneumothorax (20.8 vs. 32.8%; p = 0.001) and chest tube (8.2 vs. 20.8%; p < 0.0001) rates compared to the control group. Sub-analysis including only faculty who had >30 cases of both treatment and control cases demonstrated similar findings: the treated group had significantly lower pneumothorax (17.6 vs. 30.2%; p = 0.002) and chest tube (7.2 vs. 18%; p = 0.001) rates. The self-expanding tract sealant device significantly reduced the pneumothorax rate, and more importantly, the chest tube placement rate after percutaneous lung biopsy.
ERIC Educational Resources Information Center
Steiner, Peter M.; Cook, Thomas D.; Shadish, William R.
2011-01-01
The effect of unreliability of measurement on propensity score (PS) adjusted treatment effects has not been previously studied. The authors report on a study simulating different degrees of unreliability in the multiple covariates that were used to estimate the PS. The simulation uses the same data as two prior studies. Shadish, Clark, and Steiner…
ERIC Educational Resources Information Center
Tanner-Smith, Emily E.; Lipsey, Mark W.
2014-01-01
There are many situations where random assignment of participants to treatment and comparison conditions may be unethical or impractical. This article provides an overview of propensity score techniques that can be used for estimating treatment effects in nonrandomized quasi-experimental studies. After reviewing the logic of propensity score…
Obsuth, Ingrid; Murray, Aja Louise; Malti, Tina; Sulger, Philippe; Ribeaud, Denis; Eisner, Manuel
2017-08-01
Previous research suggests a link between the quality of teacher-student relationships and the students' behavioral outcomes; however, the observational nature of past studies makes it difficult to attribute a causal role to the quality of these relationships. In the current study, therefore, we used a propensity score analysis approach to evaluate whether students who were matched on their propensity to experience a given level of relationship quality but differed on their actual relationship quality diverged on their concurrent and subsequent problem and prosocial behavior. Student/self, teacher, and parent- (only waves 1-3) reported data from 8 waves of the Zurich Project on the Social Development of Children and Youths (z-proso), a longitudinal study of Swiss youth among a culturally diverse sample of 7- to 15-year-olds were utilized. The initial sample included 1483 (49.4 % female) students for whom information relevant for this study was available. The sample represented families from around 80 different countries, from across all the continents; with approximately 42 % of the female primary caregivers having been born in Switzerland. Following successful matching, we found that students who reported better relationships with their teachers and whose teachers reported better relationships with them evidenced fewer problem behaviors concurrently and up to 4 years later. There was also evidence for an analogous effect in predicting prosocial behavior. The implications of these findings are discussed in relation to prevention and intervention practices.
Zhang, Lin; Yang, JinKui; Li, LanTing; Liu, DongDong; Xie, XiaoPing; Dong, Peng; Lin, Yong
2018-06-11
Reducing the fluctuation of blood pressure has recently been recognized as a potential target for improving management of hypertension to prevent cardiovascular events, particularly for strokes. Some randomized controlled trials demonstrated that amlodipine can effectively reduce blood pressure as a well-established, long-acting calcium channel blocker (CCB). However, few data are available for amlodipine on blood pressure variability (BPV) in China in a real-world setting. This study aimed to assess the effect of amlodipine versus other CCB antihypertensive agents on BPV. A retrospective propensity score-matched analysis was conducted, which retrieved the encounter data from 5582 hypertensive inpatients (with a median age of 69, female percentage of 48%, diastolic blood pressure ≥40 and <150 mmHg; systolic blood pressure (SBP) ≥70 mmHg and <260 mmHg), who had taken at least one antihypertensive agent and completed at least three SBP measurements during the visit. International Classification of Diseases was used to identify the hypertensive patients. BPV was calculated with standard deviation (SD) and coefficient of variation (CV) of SBP during a single inpatient visit. The Propensity Score Matching was used to balance the cohort of patients prescribed amlodipine or other CCBs. A series of appropriate statistical tests were applied to the propensity score-matched samples to examine the different effects on BPV. Additionally, the hypertensive patients with comorbidity such as coronary artery disease, diabetes mellitus, myocardial infarction, heart failure and chronic kidney disease were analyzed. For the hypertensive patients (n = 1756, for each cohort), patients prescribed amlodipine showed lower BPV than patients prescribed other CCBs (12.90 vs 13.76 mmHg, p < 0.05 [SD] and 9.47 vs 10.06, p < 0.05 [CV]). For the hypertensive patients with comorbidity (n = 1080, for each cohort), patients prescribed amlodipine had lower BPV than patients prescribed
Giordano, Salvatore; Garvey, Patrick B; Baumann, Donald P; Liu, Jun; Butler, Charles E
2017-02-01
Previous studies suggest that bridged mesh repair for abdominal wall reconstruction may result in worse outcomes than mesh-reinforced, primary fascial closure, particularly when acellular dermal matrix is used. We compared our outcomes of bridged versus reinforced repair using ADM in abdominal wall reconstruction procedures. This retrospective study included 535 consecutive patients at our cancer center who underwent abdominal wall reconstruction either for an incisional hernia or for abdominal wall defects left after excision of malignancies involving the abdominal wall with underlay mesh. A total of 484 (90%) patients underwent mesh-reinforced abdominal wall reconstruction and 51 (10%) underwent bridged repair abdominal wall reconstruction. Acellular dermal matrix was used, respectively, in 98% of bridged and 96% of reinforced repairs. We compared outcomes between these 2 groups using propensity score analysis for risk-adjustment in multivariate analysis and for 1-to-1 matching. Bridged repairs had a greater hernia recurrence rate (33.3% vs 6.2%, P < .001), a greater overall complication rate (59% vs 30%, P = .001), and worse freedom from hernia recurrence (log-rank P <.001) than reinforced repairs. Bridged repairs also had a greater rate of wound dehiscence (26% vs 14%, P = .034) and mesh exposure (10% vs 1%, P = .003) than mesh-reinforced abdominal wall reconstruction. When the treatment method was adjusted for propensity score in the propensity-score-matched pairs (n = 100), we found that the rates of hernia recurrence (32% vs 6%, P = .002), overall complications (32% vs 6%, P = .002), and freedom from hernia recurrence (68% vs 32%, P = .001) rates were worse after bridged repair. We did not observe differences in wound healing and mesh complications between the 2 groups. In our population of primarily cancer patients at MD Anderson Cancer Center bridged repair for abdominal wall reconstruction is associated with worse outcomes than mesh
Stuart, Beth L; Grebel, Louise En; Butler, Christopher C; Hood, Kerenza; Verheij, Theo J M; Little, Paul
2017-09-01
Although randomised controlled trials (RCTs) are considered 'gold standard' evidence, they are not always feasible or appropriate, and may represent a select population. Observational studies provide a useful alternative to enhance applicability, but results can be biased due to confounding. To explore the utility of propensity scores for causal inference in an observational study. Comparison of the effect of amoxicillin on key outcomes in an international RCT and observational study of lower respiratory tract infections. Propensity scores were calculated and applied as probability weights in the analyses. The adjusted results were compared with the effects reported in the RCT. Groups were well balanced in the RCT but significantly imbalanced in the observational study, with evidence of confounding by indication: patients receiving antibiotics tended to be older and more unwell at baseline consultation. In the trial duration of symptoms (hazard ratio 1.06, 95% CI = 0.96 to 1.18) and symptom severity (-0.07, 95% CI = -0.15 to 0.007) did not differ between groups. Weighting by propensity score in the observational study resulted in very similar estimates of effect: duration of symptoms (hazard ratio 1.06, 95% CI = 0.80 to 1.40) and difference for symptom severity (-0.07, 95% CI = -0.34 to 0.20). The observational study, after conditioning on propensity score, echoed the trial results. Provided that detailed information is available on potential sources of confounding, effects of interventions can probably be assessed reasonably well in observational datasets, allowing them to be more directly compared with the results of RCTs. © British Journal of General Practice 2017.
Ji, Mi Seon; Jeong, Myung Ho; Ahn, Young Keun; Kim, Sang Hyung; Kim, Young Jo; Chae, Shung Chull; Hong, Taek Jong; Seong, In Whan; Chae, Jei Keon; Kim, Chong Jin; Cho, Myeong Chan; Rha, Seung-Woon; Bae, Jang Ho; Seung, Ki Bae; Park, Seung Jung
2016-12-15
It is unclear whether simvastatin-ezetimibe could be an alternative therapy to high-intensity statin therapy in high-risk patients. The aim of this study was to compare the clinical outcomes of simvastatin-ezetimibe and high-intensity statin therapy in patients with acute myocardial infarction (AMI), and especially in those with high-risk factor. A total of 3520 AMI patients in the KAMIR (Korea Acute Myocardial Infarction Registry) were classified into simvastatin-ezetimibe group (n=1249) and high-intensity statin group (n=2271). Multivariate analysis and propensity-score matching analysis were performed. The primary endpoint was major adverse cardiac events (MACE) at 12-months follow-up. In overall AMI patients, MACE occurred in 116 patients (9.3%) in simvastatin-ezetimibe group and 116 patients (5.1%) in high-intensity statin group. The difference in MACE between groups was driven by repeat revascularization (5.9% vs. 2.2%). After propensity matching analysis, simvastatin-ezetimibe was associated with a higher incidence of MACE than high-intensity statin therapy (adjusted hazard ratio: 3.090, 95% confidence interval: 1.715 to 5.566, p<0.001). However, in patients with high-risk factors, such as diabetes, old age, or heart failure, simvastatin-ezetimibe had similar incidence of MACE compared with high-intensity statin therapy in further adjusted analysis. In overall AMI patients, high-intensity statin therapy had better clinical outcomes than simvastatin-ezetimibe. However, in patients with high-risk factor, simvastatin-ezetimibe had comparable clinical outcomes to high-intensity statin therapy. Therefore, simvastatin-ezetimibe could be used as an alternative to high-intensity statin therapy in such patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Varas, Javier; Ramos, Rosa; Aljama, Pedro; Pérez-García, Rafael; Moreso, Francesc; Pinedo, Miguel; Ignacio Merello, José; Stuard, Stefano; Canaud, Bernard; Martín-Malo, Alejandro
2018-01-01
Intravenous iron management is common in the haemodialysis population. However, the safest dosing strategy remains uncertain, in terms of the risk of hospitalization and mortality. We aimed to determine the effects of cumulative monthly iron doses on mortality and hospitalization. This multicentre observational retrospective propensity-matched score study included 1679 incident haemodialysis patients. We measured baseline demographic variables, haemodialysis clinical parameters and laboratory analytical values. We compared outcomes among quartiles of cumulative iron dose (mg/kg/month). We implemented propensity-score matching (PSM) to reduce confounding due to indication. In the PSM cohort (330 patients), we compared outcomes between groups that received cumulative iron doses above and below 5.66 mg/kg/month. Kaplan-Meier analyses showed that the high iron dose group had significantly worse survival than the low iron dose group. A univariate analysis indicated that the monthly iron dose could significantly predict mortality. However, a multivariate regression did not confirm that finding. The multivariate regression analysis revealed that iron doses >5.58 mg/kg/month were not associated with elevated mortality risk, but they were associated with elevated risks of all-cause and cardiovascular-related hospitalizations. These results were ratified in the PSM population. Intravenous iron administration is advisable for maintaining haemoglobin levels in patients that receive haemodialysis. Our data suggested that large monthly iron doses, adjusted for body weight, were associated with more hospitalizations, but not with mortality or infection-related hospitalizations. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.
ERIC Educational Resources Information Center
Grzywacz, Joseph G.; Daniel, Stephanie S.; Tucker, Jenna; Walls, Jill; Leerkes, Esther
2011-01-01
Data from the National Institute for Child Health and Human Development Study of Early Child Care (Phase I) and propensity score techniques were used to determine whether working full time in a nonstandard schedule job during the child's first year predicted parenting practices over 3 years. Results indicated that women who worked full time in a…
Bidwell, L. Cinnamon; Palmer, Rohan H.C.; Brick, Leslie; Madden, Pamela A.F.; Heath, Andrew C.; Knopik, Valerie S.
2016-01-01
When examining the effects of prenatal exposure to maternal smoking during pregnancy (MSDP) on later offspring substance use, it is critical to consider familial environments confounded with MSDP. The purpose of this study was to examine the effect of MSDP on offspring's initial reactions to cigarettes and alcohol, which are indicators of future substance-use related problems. We tested these effects using two propensity score approaches (1) by controlling for confounding using the MSDP propensity score and 2) examining effects of MSDP across the MSDP risk distribution by grouping individuals into quantiles based on their MSDP propensity score. This study used data from 829 unrelated mothers with a reported lifetime history of smoking to determine the propensity for smoking only during their first trimester (MSDP-E) or throughout their entire pregnancy (MSDP-T). Propensity score analyses focused on the offspring (N=1616 female twins) of a large subset of these mothers. We examined the effects of levels of MSDP-E/T on offspring initial reactions to their first experiences with alcohol and cigarettes, across the distribution of liability for MSDP-E/T. MSDP-E/T emerged as significant predictors of offspring reactions to alcohol and cigarettes, but the effects were confounded by the familial liability for MSDP. Further, the unique MSDP effects that emerged were not uniform across the MSDP familial risk distribution. Our findings underscore the importance of properly accounting for correlated familial risk factors when examining the effects of MSDP on substance related outcomes. PMID:27098899
Jayot, Aude; Nyangoh Timoh, Krystel; Bendifallah, Sofiane; Ballester, Marcos; Darai, Emile
Our primary endpoint was to compare the intra- and postoperative complications, whereas secondary endpoints were the occurrence of voiding dysfunction and evaluation of the quality or life of segmental and discoid resection in patients with colorectal endometriosis. Retrospective study (Canadian Task Force classification II-2). Tenon University Hospital in Paris. Thirty-one 31 patients who underwent a conservative surgery and 31 patients who underwent. The 2 groups were compared using propensity score matching (PSM) analysis, with a median follow-up of 247 days (8.2 months). Discoid colorectal resection was associated with a shorter operating time (155 vs 180 minutes, p = .03) and hospital stay (7 vs 8 days, p = .002) than segmental colorectal resection; however, a similar intra- and postoperative complication rate was found. A higher rate of postoperative voiding dysfunction was observed in the segmental resection group (19% vs 45%, p = .03) as well as duration of voiding dysfunction requiring bladder self-catheterization longer than 30 days (0 vs 22%, p = .005). Our PSM analysis suggests the advantages of discoid resection because it results in a similar surgical complication rate to segmental resection but with advantages in operating time, hospital stay, and voiding dysfunction. Copyright © 2017 American Association of Gynecologic Laparoscopists. Published by Elsevier Inc. All rights reserved.
Statistical primer: propensity score matching and its alternatives.
Benedetto, Umberto; Head, Stuart J; Angelini, Gianni D; Blackstone, Eugene H
2018-06-01
Propensity score (PS) methods offer certain advantages over more traditional regression methods to control for confounding by indication in observational studies. Although multivariable regression models adjust for confounders by modelling the relationship between covariates and outcome, the PS methods estimate the treatment effect by modelling the relationship between confounders and treatment assignment. Therefore, methods based on the PS are not limited by the number of events, and their use may be warranted when the number of confounders is large, or the number of outcomes is small. The PS is the probability for a subject to receive a treatment conditional on a set of baseline characteristics (confounders). The PS is commonly estimated using logistic regression, and it is used to match patients with similar distribution of confounders so that difference in outcomes gives unbiased estimate of treatment effect. This review summarizes basic concepts of the PS matching and provides guidance in implementing matching and other methods based on the PS, such as stratification, weighting and covariate adjustment.
Grove, Erik L; Hansen, Peter Riis; Olesen, Jonas B; Ahlehoff, Ole; Selmer, Christian; Lindhardsen, Jesper; Madsen, Jan Kyst; Køber, Lars; Torp-Pedersen, Christian; Gislason, Gunnar H
2011-01-01
Objective To examine the effect of proton pump inhibitors on adverse cardiovascular events in aspirin treated patients with first time myocardial infarction. Design Retrospective nationwide propensity score matched study based on administrative data. Setting All hospitals in Denmark. Participants All aspirin treated patients surviving 30 days after a first myocardial infarction from 1997 to 2006, with follow-up for one year. Patients treated with clopidogrel were excluded. Main outcome measures The risk of the combined end point of cardiovascular death, myocardial infarction, or stroke associated with use of proton pump inhibitors was analysed using Kaplan-Meier analysis, Cox proportional hazard models, and propensity score matched Cox proportional hazard models. Results 3366 of 19 925 (16.9%) aspirin treated patients experienced recurrent myocardial infarction, stroke, or cardiovascular death. The hazard ratio for the combined end point in patients receiving proton pump inhibitors based on the time dependent Cox proportional hazard model was 1.46 (1.33 to 1.61; P<0.001) and for the propensity score matched model based on 8318 patients it was 1.61 (1.45 to 1.79; P<0.001). A sensitivity analysis showed no increase in risk related to use of H2 receptor blockers (1.04, 0.79 to 1.38; P=0.78). Conclusion In aspirin treated patients with first time myocardial infarction, treatment with proton pump inhibitors was associated with an increased risk of adverse cardiovascular events. PMID:21562004
Girardi, Daniel M; de Lima, Mariana A; Pereira, Gabriel C B; Negrão, Marcelo V; López, Rossana V M; Capareli, Fernanda C; Sabbaga, Jorge; Hoff, Paulo Marcelo G
2018-04-03
Treatment of localized gastric cancer (LGC) consists of surgical resection followed by adjuvant treatment. Both chemoradiation (CRT) and chemotherapy (CT) regimens have shown benefit in survival outcomes versus observation. However, there are few data comparing these approaches. This study included consecutive patients with LGC treated at Instituto do Cancer do Estado de Sao Paulo (ICESP) from 2012 to 2015. CRT was based on the INT-0116 regimen and CT consisted of a platinum and fluoropyrimidine doublet. Treatment choice was based on physician preference. Toxicity was evaluated for every cycle. Overall survival (OS) analysis was performed by Kaplan-Meier. A propensity score-matched analysis was performed to minimize selection bias. A total of 309 patients were evaluated, 227 in CRT group and 82 in CT group. The most prevalent grade 3/4 toxicities in CRT and CT groups were: nausea/vomiting (9.25 vs 4.9%), fatigue (9.3% vs 2.4%), mucositis (4.4% vs 1.2%), neutropenia (37.8% vs 20.9%), febrile neutropenia (3.9% vs 0%), anemia (4.3% vs 6.1%), thrombocytopenia (2.6% vs 4.9%), neuropathy (0 vs 2.4%) and hand-foot syndrome (0.4% vs 2.4%). Two grade 5 toxicities (febrile neutropenia and anemia) occurred in CRT group. There was no difference in the pattern of recurrence. After a median follow-up of 23.5 months (CRT) and 20.6 months (CT), there was no difference in OS between groups. CT and CRT present similar efficacy and tolerability as adjuvant treatment for LGC.
ERIC Educational Resources Information Center
Kretschmann, Julia; Vock, Miriam; Lüdtke, Oliver
2014-01-01
Using German data, we examined the effects of one specific type of acceleration--grade skipping--on academic performance. Prior research on the effects of acceleration has suffered from methodological restrictions, especially due to a lack of appropriate comparison groups and a priori measurements. For this reason, propensity score matching was…
Using Propensity Scores for Estimating Causal Effects: A Study in the Development of Moral Reasoning
ERIC Educational Resources Information Center
Grunwald, Heidi E.; Mayhew, Matthew J.
2008-01-01
The purpose of this study was to illustrate the use of propensity scores for creating comparison groups, partially controlling for pretreatment course selection bias, and estimating the treatment effects of selected courses on the development of moral reasoning in undergraduate students. Specifically, we used a sample of convenience for comparing…
Sabashnikov, Anton; Heinen, Stephanie; Deppe, Antje Christin; Zeriouh, Mohamed; Weymann, Alexander; Slottosch, Ingo; Eghbalzadeh, Kaveh; Popov, Aron-Frederik; Liakopoulos, Oliver; Rahmanian, Parwis B; Madershahian, Navid; Kroener, Axel; Choi, Yeong-Hoon; Kuhn-Régnier, Ferdinand; Simon, André R; Wahlers, Thorsten; Wippermann, Jens
2017-05-01
Previous research suggests that female gender is associated with increased mortality rates after surgery for Stanford A acute aortic dissection (AAD). However, women with AAD usually present with different clinical symptoms that may bias outcomes. Moreover, there is a lack of long-term results regarding overall mortality and freedom from major cerebrovascular events. We analysed the impact of gender on long-term outcomes after surgery for Stanford A AAD by comparing genders with similar risk profiles using propensity score matching. A total of 240 patients operated for Stanford A AAD were included in this study. To control for selection bias and other confounders, propensity score matching was applied to gender groups. After propensity score matching, the gender groups were well balanced in terms of risk profiles. There were no statistically significant differences regarding duration of cardiopulmonary bypass ( P = 0.165) and duration of aortic cross-clamp time ( P = 0.111). Female patients received less fresh frozen plasma ( P = 0.021), had shorter stays in the intensive care unit ( P = 0.031), lower incidence of temporary neurological dysfunction ( P < 0.001) and lower incidence of dialysis ( P = 0.008). There were no significant differences regarding intraoperative mortality ( P = 1.000), 30-day mortality ( P = 0.271), long-term overall cumulative survival ( P = 0.954) and long-term freedom from cerebrovascular events ( P = 0.235) with up to a 9-year follow-up. Considering patients with similar risk profiles, female gender per se is not associated with worse long-term survival and freedom from stroke after surgical aortic repair. Moreover, female patients might even benefit from a smoother early postoperative course and lower incidence of early postoperative complications. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights
Lee, Jun Ho; Lee, Sung Won
2016-07-01
A recent study investigated the role of testosterone (T) in chronic prostatitis or chronic pelvic pain syndrome (CP/CPPS). However, only a small amount of data is available to date, and the results are inconsistent. To evaluate the relation between total T (TT) and CP/CPPS. We conducted a propensity-matched study by identifying men with a TT level lower than 3.5 ng/mL among 8,336 men in their 40s and 50s. A control group of men with a TT level of at least 3.5 ng/mL matched for age, metabolic syndrome, and body mass index at a 5:1 ratio was selected for comparison. Using the same cohort and methods, another case group (TT < 3.0 ng/mL) and control group (TT ≥ 3.0 ng/mL) were selected. The National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) was administered. A χ(2) test, a t-test and logistic regression analyses were used to evaluate the relation between TT and prostatitis-like symptoms. Association of TT with NIH-CPSI score. After propensity score matching, 948 cases (TT < 3.5 ng/mL) and 4,740 controls (TT ≥ 3.5 ng/mL) were included. The ratio of mild and moderate to severe prostatitis-like symptoms was higher in the case group than in the control group (24.0% vs 27.4%, P = .001). The ratio of moderate to severe prostatitis-like symptoms also was higher in the case group than in the control group (6.2% vs 9.2%, P = .028). The pain domain of the NIH-CPSI, quality of life, and total NIH-CPSI scores also were higher in the case group. Ratios of severe lower urinary tract symptoms (12.6% vs 15.1%, P = .044) to maximal flow rate no higher than 10 mL/sec (3.8% vs 5.3%, P = .044) and postvoid residual urine volume of at least 100 mL (4.0% vs 5.6%, P = .035), which suggest high pressure in the prostate urethra, were higher in the case group. After adjusting for voided volume during uroflowmetry and total prostate volume, the relations of a TT level lower than 3.5 ng/mL to a maximal flow rate no higher than 10 mL/sec (odds ratio = 1.402, 95
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ahrar, Judy U., E-mail: judy.ahrar@mdanderson.org; Gupta, Sanjay; Ensor, Joe E.
PurposeTo evaluate the use of a self-expanding tract sealant device (BioSentry™) on the rates of pneumothorax and chest tube insertion after percutaneous lung biopsy.Materials and MethodsIn this retrospective study, we compared 318 patients who received BioSentry™ during percutaneous lung biopsy (treated group) with 1956 patients who did not (control group). Patient-, lesion-, and procedure-specific variables, and pneumothorax and chest tube insertion rates were recorded. To adjust for potential selection bias, patients in the treated group were matched 1:1 to patients in the control group using propensity score matching based on the above-mentioned variables. Patients were considered a match if themore » absolute difference in their propensity scores was ≤equal to 0.02.ResultsBefore matching, the pneumothorax and chest tube rates were 24.5 and 13.1% in the control group, and 21.1 and 8.5% in the treated group, respectively. Using propensity scores, a match was found for 317 patients in the treatment group. Chi-square contingency matched pair analysis showed the treated group had significantly lower pneumothorax (20.8 vs. 32.8%; p = 0.001) and chest tube (8.2 vs. 20.8%; p < 0.0001) rates compared to the control group. Sub-analysis including only faculty who had >30 cases of both treatment and control cases demonstrated similar findings: the treated group had significantly lower pneumothorax (17.6 vs. 30.2%; p = 0.002) and chest tube (7.2 vs. 18%; p = 0.001) rates.ConclusionsThe self-expanding tract sealant device significantly reduced the pneumothorax rate, and more importantly, the chest tube placement rate after percutaneous lung biopsy.« less
Shi, Lu
2010-01-01
There is controversy over to what degree banning sugar-sweetened beverage (SSB) sales at schools could decrease the SSB intake. This paper uses the adolescent sample of 2005 California Health Interview Survey to estimate the association between the availability of SSB from school vending machines and the amount of SSB consumption. Propensity score stratification and kernel-based propensity score matching are used to address the selection bias issue in cross-sectional data. Propensity score stratification shows that adolescents who had access to SSB through their school vending machines consumed 0.170 more drinks of SSB than those who did not (P < .05). Kernel-based propensity score matching shows the SSB consumption difference to be 0.158 on the prior day (P < .05). This paper strengthens the evidence for the association between SSB availability via school vending machines and the actual SSB consumption, while future studies are needed to explore changes in other beverages after SSB becomes less available. PMID:20976298
Shi, Lu
2010-01-01
There is controversy over to what degree banning sugar-sweetened beverage (SSB) sales at schools could decrease the SSB intake. This paper uses the adolescent sample of 2005 California Health Interview Survey to estimate the association between the availability of SSB from school vending machines and the amount of SSB consumption. Propensity score stratification and kernel-based propensity score matching are used to address the selection bias issue in cross-sectional data. Propensity score stratification shows that adolescents who had access to SSB through their school vending machines consumed 0.170 more drinks of SSB than those who did not (P < .05). Kernel-based propensity score matching shows the SSB consumption difference to be 0.158 on the prior day (P < .05). This paper strengthens the evidence for the association between SSB availability via school vending machines and the actual SSB consumption, while future studies are needed to explore changes in other beverages after SSB becomes less available.
ERIC Educational Resources Information Center
Zhou, Xiang; Xie, Yu
2016-01-01
Since the seminal introduction of the propensity score (PS) by Rosenbaum and Rubin, PS-based methods have been widely used for drawing causal inferences in the behavioral and social sciences. However, the PS approach depends on the ignorability assumption: there are no unobserved confounders once observed covariates are taken into account. For…
Tachibana, Hidekazu; Takagi, Toshio; Kondo, Tsunenori; Ishida, Hideki; Tanabe, Kazunari
2018-04-01
To compare surgical outcomes, including renal function and the preserved renal parenchymal volume, between robot-assisted laparoscopic partial nephrectomy and laparoscopic partial nephrectomy using propensity score-matched analyses. In total, 253 patients, with a normal contralateral kidney, who underwent laparoscopic partial nephrectomy (n = 131) or robot-assisted laparoscopic partial nephrectomy (n = 122) with renal arterial clamping between 2010 and 2015, were included. Patients' background and tumor factors were adjusted by propensity score matching. Surgical outcomes, including postoperative renal function, complications, warm ischemia time and preserved renal parenchymal volume, evaluated by volumetric analysis, were compared between the surgical procedures. After matching, 64 patients were assigned to each group. The mean age was 56-57 years, and the mean tumor size was 22 mm. Approximately 50% of patients had low complexity tumors (RENAL nephrometry score 4-7). The incidence rate of acute kidney failure was significantly lower in the robot-assisted laparoscopic partial nephrectomy (11%) than laparoscopic partial nephrectomy (23%) group (P = 0.049), and warm ischemia time shorter in the robot-assisted laparoscopic partial nephrectomy (17 min) than laparoscopic partial nephrectomy (25 min) group (P < 0.0001). The preservation rate of renal function, measured by the estimated glomerular filtration rate, at 6 months post-surgery was 96% for robot-assisted laparoscopic partial nephrectomy and 90% for laparoscopic partial nephrectomy (P < 0.0001). The preserved renal parenchymal volume was higher for robot-assisted laparoscopic partial nephrectomy (89%) than laparoscopic partial nephrectomy (77%; P < 0.0001). The rate of perioperative complications, surgical margin status and length of hospital stay were equivalent for both techniques. Robot-assisted laparoscopic partial nephrectomy allows to achieve better preservation of renal function and parenchymal volume
Do family dinners reduce the risk for early adolescent substance use? A propensity score analysis.
Hoffmann, John P; Warnick, Elizabeth
2013-01-01
The risks of early adolescent substance use on health and well-being are well documented. In recent years, several experts have claimed that a simple preventive measure for these behaviors is for families to share evening meals. In this study, we use data from the 1997 National Longitudinal Study of Youth (n = 5,419) to estimate propensity score models designed to match on a set of covariates and predict early adolescent substance use frequency and initiation. The results indicate that family dinners are not generally associated with alcohol or cigarette use or with drug use initiation. However, a continuous measure of family dinners is modestly associated with marijuana frequency, thus suggesting a potential causal impact. These results show that family dinners may help prevent one form of substance use in the short term but do not generally affect substance use initiation or alcohol and cigarette use.
Effect of dextran-70 on outcome in severe sepsis; a propensity-score matching study.
Bentzer, Peter; Broman, Marcus; Kander, Thomas
2017-07-06
Albumin may be beneficial in patients with septic shock but availability is limited and cost is high. The objective of the present study was to investigate if the use of dextran-70 in addition to albumin and crystalloids influences organ failure or mortality in patients with severe sepsis or septic shock. Patients with severe sepsis or septic shock (n = 778) admitted to a university hospital intensive care unit (ICU) between 2007 and 2015 that received dextran-70 during resuscitation were propensity score matched to controls at a 1 to 1 ratio. Outcomes were highest acute kidney injury network (AKIN) score the first 10 days in the ICU, use of renal replacement therapy, days alive and free of organ support the first 28 days after admission to ICU, mortality and events of severe bleeding. Outcomes were assessed using paired hypothesis testing. Propensity score matching resulted in two groups of patients with 245 patients in each group. The dextran group received a median volume of 1483 ml (interquartile range, 1000-2000 ml) of dextran-70 during the ICU stay. Highest AKIN score did not differ between the control- and dextran groups (1 (0-3) versus 2 (0-3), p = 0.06). Incidence of renal replacement therapy in the control- and dextran groups was similar (19% versus 22%, p = 0.42, absolute risk reduction -2.9% [95% CI: -9.9 to 4.2]). Days alive and free of renal replacement, vasopressors and mechanical ventilation did not differ between the control- and dextran groups. The 180-day mortality was 50.2% in the control group and 41.6% in the dextran group (p = 0.046, absolute risk reduction 8.6% [-0.2 to 17.4]). Fraction of patients experiencing a severe bleeding in the first 10 days in the ICU did not differ between the control and dextran groups (14% versus 18%, p = 0.21). There is a paucity of high quality data regarding effects of dextran solutions on outcome in sepsis. In the present study, propensity score matching was used in attempt to reduce bias. No
Vohra, Nasreen A; Brinkley, Jason; Kachare, Swapnil; Muzaffar, Mahvish
2018-03-02
Primary tumor resection (PTR) in metastatic breast cancer is not a standard treatment modality, and its impact on survival is conflicting. The primary objective of this study was to analyze impact of PTR on survival in metastatic patients with breast cancer. A retrospective study of metastatic patients with breast cancer was conducted using the 1988-2011 Surveillance, Epidemiology, and End Results (SEER) data base. Cox proportional hazards regression models were used to evaluate the relationship between PTR and survival and to adjust for the heterogeneity between the groups, and a propensity score-matched analysis was also performed. A total of 29 916 patients with metastatic breast cancer were included in the study, and 15 129 (51%) of patients underwent primary tumor resection, and 14 787 (49%) patients did not undergo surgery. Overall, decreasing trend in PTR for metastatic breast cancer in last decades was noted. Primary tumor resection was associated with a longer median OS (34 vs 18 months). In a propensity score-matched analysis, prognosis was also more favorable in the resected group (P = .0017). Primary tumor resection in metastatic breast cancer was associated with survival improvement, and the improvement persisted in propensity-matched analysis. © 2018 Wiley Periodicals, Inc.
Capogrosso, Paolo; Barret, Eric; Sanchez-Salas, Rafael; Nunes-Silva, Igor; Rozet, François; Galiano, Marc; Ventimiglia, Eugenio; Briganti, Alberto; Salonia, Andrea; Montorsi, Francesco; Cathelineau, Xavier
2018-01-01
To assess outcomes of whole gland high-intensity focused ultrasound (HIFU) as compared with minimally-invasive radical prostatectomy (MIRP) in elderly patients. Patients aged ≥70 years with, cT1-cT2 disease, biopsy Gleason score (GS) 3 + 3 or 3 + 4 and preoperative PSA ≤10 ng/mL were submitted to either whole-gland HIFU or MIRP. Propensity-score matching analysis was performed to ensure the baseline equivalence of groups. Follow-up visits were routinely performed assessing PSA and urinary function according to the International Continence Score (ICS) and the International Prostatic Symptoms Score (IPSS) questionnaires. Estimated rates of salvage-treatment free survival (SFS) overall-survival (OS), cancer-specific survival (CSS) and metastasis-free survival (MTS) were assessed and compared. Overall, 84 (33.3%) and 168 (66.7%) patients were treated with HIFU and MIRP, respectively. MIRP was associated with a 5-yrs SFS of 93.4% compared to 74.8% for HIFU (p < 0.01). The two groups did not differ in terms of OS and MTS. No cancer-related deaths were registered. Patients treated with HIFU showed better short-term (6-mos) continence outcomes [mean-ICS: 1.7 vs. 4.8; p = 0.005] but higher IPSS mean scores at 12-mos assessment. A comparable rate of patients experiencing post-treatment Clavien-Dindo grade ≥III complications was observed within the two groups. Whole-gland HIFU is a feasible treatment in elderly men with low-to intermediate-risk PCa and could be considered for patients either unfit for surgery, or willing a non-invasive treatment with a low morbidity burden, although a non-negligible risk of requiring subsequent treatment for recurrence should be expected. Copyright © 2017 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.
Agarwal, Prateek; Abdullah, Kalil G; Ramayya, Ashwin G; Nayak, Nikhil R; Lucas, Timothy H
2017-06-29
Reversal of therapeutic anticoagulation prior to emergency neurosurgical procedures is required in the setting of intracranial hemorrhage. Multifactor prothrombin complex concentrate (PCC) promises rapid efficacy but may increase the probability of thrombotic complications compared to fresh frozen plasma (FFP). To compare the rate of thrombotic complications in patients treated with PCC or FFP to reverse therapeutic anticoagulation prior to emergency neurosurgical procedures in the setting of intracranial hemorrhage at a level I trauma center. Sixty-three consecutive patients on warfarin therapy presenting with intracranial hemorrhage who received anticoagulation reversal prior to emergency neurosurgical procedures were retrospectively identified between 2007 and 2016. They were divided into 2 cohorts based on reversal agent, either PCC (n = 28) or FFP (n = 35). The thrombotic complications rates within 72 h of reversal were compared using the χ 2 test. A multivariate propensity score matching analysis was used to limit the threat to interval validity from selection bias arising from differences in demographics, laboratory values, history, and clinical status. Thrombotic complications were uncommon in this neurosurgical population, occurring in 1.59% (1/63) of treated patients. There was no significant difference in the thrombotic complication rate between groups, 3.57% (1/28; PCC group) vs 0% (0/35; FFP group). Propensity score matching analysis validated this finding after controlling for any selection bias. In this limited sample, thrombotic complication rates were similar between use of PCC and FFP for anticoagulation reversal in the management of intracranial hemorrhage prior to emergency neurosurgical procedures. Copyright © 2017 by the Congress of Neurological Surgeons
Nakamura, Koshi; Watanabe, Makoto; Okuda, Nagako; Yoshita, Katsushi; Kabayama, Mai; Torii, Sayuki; Kuribayashi, Toru; Itai, Kazuyoshi; Kamide, Kei; Miura, Katsuyuki; Okayama, Akira
2018-04-01
We investigated whether 2 types of personalized health guidance (repeated and single counseling) in the Japanese nationwide cardiovascular prevention system promoted smoking cessation among smokers. The study included 47,745 Japanese smokers aged 40 to 74 years classified into 2 personalized health guidance schemes. After a 1-year follow-up, we compared the rates of smoking cessation between individuals who had received counseling ("supported") and those who had not received counseling ("unsupported"). Using propensity score matching analysis, we estimated the average treatment effect (ATE) of each approach on smoking cessation after balancing out the characteristics between the supported and unsupported groups. The propensity score regression model included age, medical insurance type, weight gain since the age of 20 years, exercise, eating habits, alcohol intake, quality of sleep, readiness to modify lifestyle, willingness to receive support, and body mass index. In the repeated counseling scheme, the age-adjusted rates of smoking cessation in the supported and unsupported groups were 8.8% and 6.3% for males, and 9.8% and 9.1% for females respectively. In the single counseling scheme, the corresponding rates were 8.4% and 7.3% for supported and unsupported males, and 11.0% and 11.7% for supported and unsupported females respectively. The ATE of repeated counseling was +2.64% (95% confidence interval: +1.51% to +3.77%) for males and +3.11% (-1.85% to +8.07%) for females. The ATE of single counseling was +0.61% (-1.17% to +2.38%) for males and -1.06% (-5.96% to +3.85%) for females. In the Japanese cardiovascular prevention system, repeated counseling may promote smoking cessation among male smokers.
Power, Robert A; Cohen-Woods, Sarah; Ng, Mandy Y; Butler, Amy W; Craddock, Nick; Korszun, Ania; Jones, Lisa; Jones, Ian; Gill, Michael; Rice, John P; Maier, Wolfgang; Zobel, Astrid; Mors, Ole; Placentino, Anna; Rietschel, Marcella; Aitchison, Katherine J; Tozzi, Federica; Muglia, Pierandrea; Breen, Gerome; Farmer, Anne E; McGuffin, Peter; Lewis, Cathryn M; Uher, Rudolf
2013-09-01
Stressful life events are an established trigger for depression and may contribute to the heterogeneity within genome-wide association analyses. With depression cases showing an excess of exposure to stressful events compared to controls, there is difficulty in distinguishing between "true" cases and a "normal" response to a stressful environment. This potential contamination of cases, and that from genetically at risk controls that have not yet experienced environmental triggers for onset, may reduce the power of studies to detect causal variants. In the RADIANT sample of 3,690 European individuals, we used propensity score matching to pair cases and controls on exposure to stressful life events. In 805 case-control pairs matched on stressful life event, we tested the influence of 457,670 common genetic variants on the propensity to depression under comparable level of adversity with a sign test. While this analysis produced no significant findings after genome-wide correction for multiple testing, we outline a novel methodology and perspective for providing environmental context in genetic studies. We recommend contextualizing depression by incorporating environmental exposure into genome-wide analyses as a complementary approach to testing gene-environment interactions. Possible explanations for negative findings include a lack of statistical power due to small sample size and conditional effects, resulting from the low rate of adequate matching. Our findings underscore the importance of collecting information on environmental risk factors in studies of depression and other complex phenotypes, so that sufficient sample sizes are available to investigate their effect in genome-wide association analysis. Copyright © 2013 Wiley Periodicals, Inc.
The impacts of speed cameras on road accidents: an application of propensity score matching methods.
Li, Haojie; Graham, Daniel J; Majumdar, Arnab
2013-11-01
This paper aims to evaluate the impacts of speed limit enforcement cameras on reducing road accidents in the UK by accounting for both confounding factors and the selection of proper reference groups. The propensity score matching (PSM) method is employed to do this. A naïve before and after approach and the empirical Bayes (EB) method are compared with the PSM method. A total of 771 sites and 4787 sites for the treatment and the potential reference groups respectively are observed for a period of 9 years in England. Both the PSM and the EB methods show similar results that there are significant reductions in the number of accidents of all severities at speed camera sites. It is suggested that the propensity score can be used as the criteria for selecting the reference group in before-after control studies. Speed cameras were found to be most effective in reducing accidents up to 200 meters from camera sites and no evidence of accident migration was found. Copyright © 2013 Elsevier Ltd. All rights reserved.
ERIC Educational Resources Information Center
Diaz, Juan Jose; Handa, Sudhanshu
2006-01-01
Not all policy questions can be addressed by social experiments. Nonexperimental evaluation methods provide an alternative to experimental designs but their results depend on untestable assumptions. This paper presents evidence on the reliability of propensity score matching (PSM), which estimates treatment effects under the assumption of…
Hanson, Summer E; Meaike, Jesse D; Selber, Jesse C; Liu, Jun; Li, Liang; Hassid, Victor J; Baumann, Donald P; Butler, Charles E; Garvey, Patrick B
2018-05-01
Although multiple acellular dermal matrix sources exist, it is unclear how its processing impacts complication rates. The authors compared complications between two preparations of human cadaveric acellular dermal matrix (freeze dried and ready-to-use) in immediate tissue expander breast reconstruction to analyze the effect of processing on complications. The authors retrospectively reviewed all alloplastic breast reconstructions with freeze-dried or ready-to-use human acellular dermal matrices between 2006 and 2016. The primary outcome measure was surgical-site occurrence defined as seroma, skin dehiscence, surgical-site infection, or reconstruction failure. The two groups were compared before and after propensity score matching. The authors included 988 reconstructions (freeze-dried, 53.8 percent; ready-to-use, 46.2 percent). Analysis of 384 propensity score-matched pairs demonstrated a slightly higher rate of surgical-site occurrence (21.4 percent versus 16.7 percent; p = 0.10) and surgical-site infection (9.6 percent versus 7.8 percent; p = 0.13) in the freeze-dried group than in the ready-to-use group, but the difference was not significant. However, failure was significantly higher for the freeze-dried versus ready-to-use group (7.8 percent versus 4.4 percent; p = 0.050). This is the largest study comparing the outcomes of alloplastic breast reconstruction using human acellular dermal matrix materials prepared by different methods. The authors demonstrated higher early complications with aseptic, freeze-dried matrix than with sterile ready-to-use matrix; reconstructive failure was the only outcome to achieve statistical significance. The authors conclude that acellular dermal matrix preparation has an independent impact on patient outcomes in their comparison of one company's product. Therapeutic, III.
Takamori, Shinkichi; Tagawa, Tetsuzo; Toyokawa, Gouji; Ueo, Hiroki; Shimokawa, Mototsugu; Kinoshita, Fumihiko; Matsubara, Taichi; Kozuma, Yuka; Haratake, Naoki; Akamine, Takaki; Katsura, Masakazu; Takada, Kazuki; Hirai, Fumihiko; Shoji, Fumihiro; Okamoto, Tatsuro; Oda, Yoshinao; Maehara, Yoshihiko
2018-05-29
The aim of this study was to elucidate the relationship between family-associated factors and the postoperative prognosis in patients with nonsmall cell lung cancer (NSCLC). Additionally, we investigated whether having children was associated with the postoperative maintenance of the nutritional status. We selected 438 NSCLC patients who had undergone curative lung resection between 2004 and 2011 at Kyushu University (Fukuoka, Japan), whose family-associated factors were available. Nutritional indices, including the prognostic nutritional index (PNI), were used to estimate the change in the nutritional status for 1 year after surgery. A propensity score analysis was conducted after adjusting the following variables: sex, age, smoking history, performance status, pathological stage, and histological type. Three hundred patients (68.5%) had both children and partners. Forty-nine patients (11.2%) only had children, and 56 (12.8%) patients only had a partner. Thirty-three patients (7.5%) did not have a partner or children. The overall survival (OS) and disease-free survival (DFS) of the partner-present and partner-absent patients did not differ to a statistically significant extent (P = .862 and P = .712, respectively). However, childless patients showed significantly shorter OS and DFS in comparison with patients with children (P = .005 and P = .002, respectively). The postoperative exacerbation of PNI was significantly greater in childless patients than in patients with children (P = .003). These results remained after propensity score matching. Childless patients had a significantly poorer postoperative prognosis than those with children. Surgeons caring for childless NSCLC patients should be aware of the poorer postoperative outcomes in this population. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.
Broering, Dieter C; Elsheikh, Yasser; Shagrani, Mohammed; Abaalkhail, Faisal; Troisi, Roberto I
2018-02-28
Left lateral sectionectomy for donor hepatectomy is a well-established alternative to deceased donor pediatric liver transplantation. However, very little is available on the laparoscopic approach (L-LLS). With the aim to assess safety, reproducibility under proctorship and outcomes following LDLT in children, a comparative single center series using the propensity score matching (PSM) to evaluate open (O-LLS) vs. L-LLS was carried out in a relatively short time period in a high volume pediatric transplant center. A retrospective, observational, single-center, propensity score matched study was conducted on 220 consecutive living donor hepatectomies from January 2011 to April 2017. The variables considered for PSM were: year of operation, recipient age, indication for transplant, recipient weight, donor gender, donor age and donor body mass index. After matching, 72 O-LLS were fit to be compared with 72 L-LLS. Operative time and warm ischemia time were significantly longer in L-LLS whereas blood loss and overall donor complication rates were significantly lower. Postoperative day 1 and 4 pain scores were significantly less in the L-LLS group (p=0.015 and 0.003, respectively). The length of hospital stay was significantly shorter in L-LLS (4.6 vs 4.1 days) (p=0.014). Overall donor biliary complications were 9(12.5%) and 1(1.3%), respectively for O-LLS and L-LLS (p=0.022). Vascular complications occurred in 3(4.2%) children without graft loss in the laparoscopic group. The 1-3 and 5-year overall patient survival were 98.5%, 90.9% and 90.9% in the O-LLS group and in the L-LLS group 94.3%, 92.7% and 86.8% (p=0.280). Laparoscopic left lateral sectionectomy for donor hepatectomy is a safe and reproducible technique yielding better donors' perioperative outcomes respect to the conventional approach with similar recipients' outcomes. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.
Suzuki, Sho; Gotoda, Takuji; Kobayashi, Yoshiyuki; Kono, Shin; Iwatsuka, Kunio; Yagi-Kuwata, Naoko; Kusano, Chika; Fukuzawa, Masakatsu; Moriyasu, Fuminori
2016-02-01
Although endoscopic submucosal dissection (ESD) is a significant advancement in therapeutic endoscopy, it is a complicated technique and requires considerable expertise. In this exploratory study, we evaluated the efficacy of a simple traction method that uses dental floss and a hemoclip (DFC) and was developed to overcome the technical difficulties of ESD. In total, 238 early gastric cancers treated by ESD between May 2012 and December 2014 at Tokyo Medical University were retrospectively reviewed. Lesions treated by conventional ESD (n = 185) and by ESD with DFC (ESD-DFC) (n = 53) were compared. Multivariable analyses and propensity score matching were used to compensate for the differences in age, sex, resected specimen size, lesion location, lesion position, presence of ulceration, and operator level. The procedure time, rate of en bloc and complete resection, and rates of adverse events were evaluated between the 2 groups. Propensity score matching analysis created 43 matched pairs. Adjusted comparisons between ESD-DFC and conventional ESD showed similar treatment outcomes (en bloc resection rate: 97.7% vs 100%, P = .315; complete resection rate: 90.7% vs 95.3%, P = .397; perforation during ESD rate: 2.3% vs 2.3%, P = 1.000; post-ESD bleeding rate: 4.7% vs 4.7%, P = 1.000) but a significantly shorter procedure time for ESD-DFC (82.2 ± 79.5 minutes vs 118.2 ± 71.6 minutes, P = .002). ESD-DFC facilitated rapid ESD with good visualization and traction while ensuring high curability and safety. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.
Kim, Joo Yeong; Shin, Sang Do; Ro, Young Sun; Song, Kyoung Jun; Lee, Eui Jung; Park, Chang Bae; Hwang, Seung Sik
2013-08-01
This study aimed to determine whether active post-resuscitation care (APRC) was associated with improved out-of-hospital cardiac arrest (OHCA) outcomes on a nationwide level. We used a national OHCA cohort database consisting of hospital and ambulance data. We included all survivors of OHCA, excluding patients with non-cardiac etiology, younger than 15 years, and with unknown outcomes, from (2008 to 2010). The APRC was defined when the OHCA patients received mild therapeutic hypothermia (MTH) or active cardiac care (ACC), such as intravenous thrombolysis, percutaneous coronary intervention, coronary artery bypass surgery, and pacemaker/implantable cardioverter defibrillator insertion, as well as routine intensive care; patients receiving conservative post-resuscitation care (CPRC) served as the other group. The primary and secondary outcomes were survival to discharge and a good neurological outcome (cerebral performance category [CPC] 1-2), respectively. We extracted propensity-matched samples to control for selection bias. A multivariable logistic regression analysis was used to compare the APRC and CPRC groups adjusting for potential risks to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). Of total 64,155 patients, 4557 survived to admission and were included in the final analysis. Out of these patients, 1599 (35.1%) cases survived to discharge, and 499 (11.0%) cases were discharged with good neurological recoveries. Overall, 695 cases (15.3%) received any APRC, including MTH (n=377, 8.3%) and ACC (370, 8.1%). The outcomes was better in the APRC group than in the CPRC group for survival to discharge (58.7% vs. 30.8%, p<0.001) and good neurological outcome (27.2% vs. 8.0%, p<0.001), respectively. In the total cohort, the adjusted ORs of the APRC group compared to those the CPRC group were 2.15 (95% CI 1.78-2.59) for survival to discharge and 2.54 (95% CI 1.98-3.27) for a good neurological outcome. In the propensity score
Hsu, Hui-Min; Chou, Kuei-Ru; Lin, Kuan-Chia; Chen, Kuan-Yu; Su, Shu-Fang; Chung, Min-Huey
2015-10-01
We evaluated the effects of cognitive behavioral therapy for insomnia (CBT-I) in inpatients with a diagnosis of depression and comorbid insomnia. This study used a prospective, parallel-group design. The experimental group received CBT-I for no more than 90 min once weekly for 6 weeks and the control group only have health education manuals for insomnia. The following questionnaires were administered at baseline: the Hamilton Rating Scale for Depression (HAM-D), Dysfunctional Beliefs and Attitudes about Sleep (DBAS), Presleep Arousal Scale (PSAS), Sleep Hygiene Practice (SHP), and Pittsburgh Sleep Quality Index. The questionnaires were readministered after the completion of the 6-wk CBT-I intervention and 1 month following the completion of CBT-I, to determine the effects of the CBT-I intervention over time. The analysis of Generalized Estimation Equations was identified the difference between the experimental group and the control group by controlling for the variables in BZD dose and propensity score of gender, age, and the scores for the DBAS-16, PSAS, SHPS, and HAM-D. Consequently, the significant difference in the PSQI scores was observed at the 1-month follow-up assessment however, no significant intergroup difference in the PSQI scores was found at the completion of the CBT-I intervention between two groups. As a conclusion, we found that overall sleep quality significantly improved in patients who received CBT-I after we controlled for the BZD dose and propensity score, which suggests that CBT-I may represent a useful clinical strategy for improving sleep quality in patients with depression and comorbid insomnia. Copyright © 2015 Elsevier Ltd. All rights reserved.
Tumlinson, Samuel E; Sass, Daniel A; Cano, Stephanie M
2014-03-01
While experimental designs are regarded as the gold standard for establishing causal relationships, such designs are usually impractical owing to common methodological limitations. The objective of this article is to illustrate how propensity score matching (PSM) and using propensity scores (PS) as a covariate are viable alternatives to reduce estimation error when experimental designs cannot be implemented. To mimic common pediatric research practices, data from 140 simulated participants were used to resemble an experimental and nonexperimental design that assessed the effect of treatment status on participant weight loss for diabetes. Pretreatment participant characteristics (age, gender, physical activity, etc.) were then used to generate PS for use in the various statistical approaches. Results demonstrate how PSM and using the PS as a covariate can be used to reduce estimation error and improve statistical inferences. References for issues related to the implementation of these procedures are provided to assist researchers.
Arpino, Bruno; Cannas, Massimo
2016-05-30
This article focuses on the implementation of propensity score matching for clustered data. Different approaches to reduce bias due to cluster-level confounders are considered and compared using Monte Carlo simulations. We investigated methods that exploit the clustered structure of the data in two ways: in the estimation of the propensity score model (through the inclusion of fixed or random effects) or in the implementation of the matching algorithm. In addition to a pure within-cluster matching, we also assessed the performance of a new approach, 'preferential' within-cluster matching. This approach first searches for control units to be matched to treated units within the same cluster. If matching is not possible within-cluster, then the algorithm searches in other clusters. All considered approaches successfully reduced the bias due to the omission of a cluster-level confounder. The preferential within-cluster matching approach, combining the advantages of within-cluster and between-cluster matching, showed a relatively good performance both in the presence of big and small clusters, and it was often the best method. An important advantage of this approach is that it reduces the number of unmatched units as compared with a pure within-cluster matching. We applied these methods to the estimation of the effect of caesarean section on the Apgar score using birth register data. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Tada, Toshifumi; Kumada, Takashi; Toyoda, Hidenori; Kiriyama, Seiki; Tanikawa, Makoto; Hisanaga, Yasuhiro; Kanamori, Akira; Kitabatake, Shusuke; Yama, Tsuyoki
2015-09-01
It has been reported that the branched-chain amino acid (BCAA) to tyrosine ratio (BTR) is a useful indicator of liver function and BCAA therapy is associated with a decreased incidence of hepatocellular carcinoma (HCC). However, there has not been sufficient research on the relationship between BTR and the effects of BCAA therapy after initial treatment of HCC. We investigated the impact of BTR and BCAA therapy on survival in patients with HCC. A total of 315 patients with HCC who were treated (n = 66) or not treated (n = 249) with BCAA were enrolled; of these, 66 were selected from each group using propensity score matching. Survival from liver-related mortality was analyzed. In patients who did not receive BCAA therapy (n = 249), multivariate analysis for factors associated with survival indicated that low BTR (≤ 4.4) was independently associated with poor prognosis in patients with HCC (hazard ratio, 1.880; 95% confidence interval, 1.125-3.143; P = 0.016). In addition, among patients selected by propensity score matching (n = 132), multivariate analysis indicated that BCAA therapy was independently associated with good prognosis in patients with HCC (hazard ratio, 0.524; 95% confidence interval, 0.282-0.973; P = 0.041). BTR was not significantly associated with survival. Intervention involving BCAA therapy improved survival in patients with HCC versus untreated controls, regardless of BTR. In addition, low BTR was associated with poor prognosis in patients who did not receive BCAA therapy. © 2015 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.
de'Angelis, Nicola; Abdalla, Solafah; Bianchi, Giorgio; Memeo, Riccardo; Charpy, Cecile; Petrucciani, Niccolo; Sobhani, Iradj; Brunetti, Francesco
2018-05-31
Minimally invasive surgery in elderly patients with colorectal cancer remains controversial. The study aimed to compare the operative, postoperative, and oncologic outcomes of robotic (robotic colorectal resection surgery [RCRS]) versus laparoscopic colorectal resection surgery (LCRS) in elderly patients with colorectal cancer. Propensity score matching (PSM) was used to compare patients aged 70 years and more undergoing elective RCRS or LCRS for colorectal cancer between 2010 and 2017. Overall, 160 patients underwent elective curative LCRS (n = 102) or RCRS (n = 58) for colorectal cancer. Before PSM, the mean preoperative Charlson score and the tumor size were significantly lower in the robotic group. After matching, 43 RCRSs were compared with 43 LCRSs. The RCRS group showed longer operative times (300.6 versus 214.5 min, P = .03) compared with LCRS, but all other operative variables were comparable between the two groups. No differences were found for postoperative morbidity, mortality, time to flatus, return to regular diet, and length of hospital stay. R0 resection was obtained in 95.3% of procedures. The overall and disease-free survival rates at 1, 2, and 3 years were similar between RCRS and LCRS patients. The presence of more than one comorbidity before surgery was significantly associated with the incidence of postoperative complications. In patients aged 70 years or more, robotic colorectal surgery showed operative and oncologic outcomes similar to those obtained by laparoscopy, despite longer operative times. Randomized trials are awaited to reliably assess the clinical and oncological noninferiority and the costs/benefits ratio of robotic colorectal surgery in elderly populations.
Assini-Meytin, Luciana C; Green, Kerry M
2015-05-01
The aim of this study was to improve understanding of long-term socioeconomic consequences of teen parenting for men and women. Analysis is based on the Woodlawn Study, a longitudinal study of an African-American cohort from a socially disadvantaged community in Chicago; data were collected at childhood (N = 1,242), adolescence (N = 705), young adulthood (age 32 years, N = 952), and midlife (age 42 years, N = 833). This analysis focused on the 1,050 individuals with data on teen parenting. We used propensity score matching to account for differences in background characteristics between teenage parents and their peers and used multiple imputation to account for differential attrition. The regression models after propensity score matching showed that at the age of 32 years, in comparison to nonteen mothers, teenage mothers were more likely to be unemployed, live in poverty, depend on welfare, and have earned a GED or completed high school compared to finishing college. At the age of 32 years, teen fathers were more likely to be without a job than nonteen fathers. At the age of 42 years, the effect of teen parenting for women remained statistically significant for education and income. There were no significant associations between teen parenting and outcomes for men at the age of 42 years. Socioeconomic consequences of teenage parenting among African-Americans from disadvantaged background seem to be primarily concentrated in women and persist throughout adulthood. In addition to promoting the delay of parenting after the teenage years, it is critical to provide programs at early stages in the life course to mitigate the negative socioeconomic consequences of teenage motherhood as effects for women are broad. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.
Wilhelm, Alexander; Galata, Christian; Beutner, Ulrich; Schmied, Bruno M; Warschkow, Rene; Steffen, Thomas; Brunner, Walter; Post, Stefan; Marti, Lukas
2018-03-01
This study assessed the influence of tumor localization of small bowel adenocarcinoma on survival after surgical resection. Patients with resected small bowel adenocarcinoma, ACJJ stage I-III, were identified from the Surveillance, Epidemiology, and End Results database from 2004 to 2013. The impact of tumor localization on overall and cancer-specific survival was assessed using Cox proportional hazard regression models with and without risk-adjustment and propensity score methods. Adenocarcinoma was localized to the duodenum in 549 of 1025 patients (53.6%). There was no time trend for duodenal localization (P = 0.514). The 5-year cancer-specific survival rate was 48.2% (95%CI: 43.3-53.7%) for patients with duodenal carcinoma and 66.6% (95%CI: 61.6-72.1%) for patients with cancer located in the jejunum or ileum. Duodenal localization was associated with worse overall and cancer-specific survival in univariable (HR = 1.73; HR = 1.81, respectively; both P < 0.001), multivariable (HR = 1.52; HR = 1.65; both P < 0.001), and propensity score-adjusted analyses (HR = 1.33, P = 0.012; HR = 1.50, P = 0.002). Furthermore, young age, retrieval of more than 12 regional lymph nodes, less advanced stage, and married matrimonial status were positive, independent prognostic factors. Duodenal localization is an independent risk factor for poor survival after resection of adenocarcinoma. © 2017 Wiley Periodicals, Inc.
Bisleri, Gianluigi; Giroletti, Laura; Hrapkowicz, Tomasz; Bertuletti, Martina; Zembala, Marian; Arieti, Mario; Muneretto, Claudio
2016-10-01
Despite the popularity of less invasive approaches for conduits procurement in coronary artery bypass graft surgery, concerns have been raised about the potential detrimental effects of the endoscopic technique when compared with the conventional "open" technique. Among 470 patients undergoing coronary surgery with the use of a radial artery conduit, a propensity score analysis was performed among those patients assigned either to an open technique (n = 82) or to an endoscopic approach (n = 82). Endoscopic harvesting was performed with a nonsealed system. The primary endpoint was cardiac-related mortality, and secondary endpoint was survival free from major cardiac and cerebrovascular adverse events. Moreover, hand and forearm sensory discomfort and forearm wound healing were also assessed. No conversion to the open technique occurred in patients undergoing endoscopic harvesting. No patients in either group showed hand ischemia; wound infection occurred only in the open group (open 7.3% versus endoscopic 0%, p = 0.007). Wound healing (Hollander scale) was considerably better in the endoscopic group (open 3.3, endoscopic 4.7; p < 0.001) as well as paresthesia at the latest follow-up (open 19.5% versus endoscopic 3.6%, p < 0.001). Pain (visual analog scale score) was significantly reduced with the endoscopic technique (open 3.2, endoscopic 1.2; p = 0.003). At 5 years of follow-up, freedom from cardiac-related mortality (open 96.3% ± 2.1% versus endoscopic 98.1% ± 1.8%; p = 0.448) as well as survival free from major cardiac and cerebrovascular adverse events (open 93.9% ± 2.6% versus endoscopic 93% ± 3.4%; p = 0.996) were similar among the groups. Endoscopic radial artery harvesting allows for incremental benefits in the short term in terms of improved cosmesis and reduced wound and neurologic complications, without yielding detrimental effects in terms of graft-related events at 5 years of follow-up. Copyright © 2016 The Society of Thoracic Surgeons
NASA Astrophysics Data System (ADS)
Hudson, P.; Botzen, W. J. W.; Kreibich, H.; Bubeck, P.; Aerts, J. C. J. H.
2014-01-01
The employment of damage mitigation measures by individuals is an important component of integrated flood risk management. In order to promote efficient damage mitigation measures, accurate estimates of their damage mitigation potential are required. That is, for correctly assessing the damage mitigation measures' effectiveness from survey data, one needs to control for sources of bias. A biased estimate can occur if risk characteristics differ between individuals who have, or have not, implemented mitigation measures. This study removed this bias by applying an econometric evaluation technique called Propensity Score Matching to a survey of German households along along two major rivers major rivers that were flooded in 2002, 2005 and 2006. The application of this method detected substantial overestimates of mitigation measures' effectiveness if bias is not controlled for, ranging from nearly € 1700 to € 15 000 per measure. Bias-corrected effectiveness estimates of several mitigation measures show that these measures are still very effective since they prevent between € 6700-14 000 of flood damage. This study concludes with four main recommendations regarding how to better apply Propensity Score Matching in future studies, and makes several policy recommendations.
NASA Astrophysics Data System (ADS)
Hudson, P.; Botzen, W. J. W.; Kreibich, H.; Bubeck, P.; Aerts, J. C. J. H.
2014-07-01
The employment of damage mitigation measures (DMMs) by individuals is an important component of integrated flood risk management. In order to promote efficient damage mitigation measures, accurate estimates of their damage mitigation potential are required. That is, for correctly assessing the damage mitigation measures' effectiveness from survey data, one needs to control for sources of bias. A biased estimate can occur if risk characteristics differ between individuals who have, or have not, implemented mitigation measures. This study removed this bias by applying an econometric evaluation technique called propensity score matching (PSM) to a survey of German households along three major rivers that were flooded in 2002, 2005, and 2006. The application of this method detected substantial overestimates of mitigation measures' effectiveness if bias is not controlled for, ranging from nearly EUR 1700 to 15 000 per measure. Bias-corrected effectiveness estimates of several mitigation measures show that these measures are still very effective since they prevent between EUR 6700 and 14 000 of flood damage per flood event. This study concludes with four main recommendations regarding how to better apply propensity score matching in future studies, and makes several policy recommendations.
Propensity score method: a non-parametric technique to reduce model dependence
2017-01-01
Propensity score analysis (PSA) is a powerful technique that it balances pretreatment covariates, making the causal effect inference from observational data as reliable as possible. The use of PSA in medical literature has increased exponentially in recent years, and the trend continue to rise. The article introduces rationales behind PSA, followed by illustrating how to perform PSA in R with MatchIt package. There are a variety of methods available for PS matching such as nearest neighbors, full matching, exact matching and genetic matching. The task can be easily done by simply assigning a string value to the method argument in the matchit() function. The generic summary() and plot() functions can be applied to an object of class matchit to check covariate balance after matching. Furthermore, there is a useful package PSAgraphics that contains several graphical functions to check covariate balance between treatment groups across strata. If covariate balance is not achieved, one can modify model specifications or use other techniques such as random forest and recursive partitioning to better represent the underlying structure between pretreatment covariates and treatment assignment. The process can be repeated until the desirable covariate balance is achieved. PMID:28164092
Marui, Akira; Kimura, Takeshi; Tanaka, Shiro; Furukawa, Yutaka; Kita, Toru; Sakata, Ryuzo
2012-01-01
Although there have been several studies that compared the efficacy of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), the impact of off-pump CABG (OPCAB) has not been well elucidated. The objective of the present study was to compare the outcomes after PCI, on-pump CABG (ONCAB), and OPCAB in patients with multivessel and/or left main disease. Among the 9877 patients undergoing first PCI using bare-metal stents or CABG who were enrolled in the CREDO-Kyoto Registry, 6327 patients with multivessel and/or left main disease were enrolled into the present study (67.9±9.8 years old). Among them, 3877 patients received PCI, 1388 ONCAB, and 1069 OPCAB. Median follow-up was 3.5 years. Comparing PCI with all CABG (ONCAB and OPCAB), propensity-score-adjusted all-cause mortality after PCI was higher than that CABG (hazard ratio (95% confidence interval): 1.37 (1.15-1.63), p<0.01). The incidence of stroke was lower after PCI than that after CABG (0.75 (0.59-0.96), p=0.02). CABG was associated with better survival outcomes than PCI in the elderly (interaction p=0.04). Comparing OPCAB with PCI or ONCAB, propensity-score-adjusted all-cause mortality after PCI was higher than that after OPCAB (1.50 (1.20-1.86), p<0.01). Adjusted mortality was similar between ONCAB and OPCAB (1.18 (0.93-1.51), p=0.33). The incidence of stroke after OPCAB was similar to that after PCI (0.98 (0.71-1.34), p>0.99), but incidence of stroke after ONCAB was higher than that after OPCAB (1.59 (1.16-2.18), p<0.01). In patients with multivessel and/or left main disease, CABG, particularly OPCAB, is associated with better survival outcomes than PCI using bare-metal stents. Survival outcomes are similar between ONCAB and OPCAB.
Marui, Akira; Kimura, Takeshi; Tanaka, Shiro; Furukawa, Yutaka; Kita, Toru; Sakata, Ryuzo
2012-01-01
OBJECTIVE Although there have been several studies that compared the efficacy of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), the impact of off-pump CABG (OPCAB) has not been well elucidated. The objective of the present study was to compare the outcomes after PCI, on-pump CABG (ONCAB), and OPCAB in patients with multivessel and/or left main disease. METHODS Among the 9877 patients undergoing first PCI using bare-metal stents or CABG who were enrolled in the CREDO-Kyoto Registry, 6327 patients with multivessel and/or left main disease were enrolled into the present study (67.9 ± 9.8 years old). Among them, 3877 patients received PCI, 1388 ONCAB, and 1069 OPCAB. Median follow-up was 3.5 years. RESULTS Comparing PCI with all CABG (ONCAB and OPCAB), propensity-score-adjusted all-cause mortality after PCI was higher than that CABG (hazard ratio (95% confidence interval): 1.37 (1.15–1.63), p < 0.01). The incidence of stroke was lower after PCI than that after CABG (0.75 (0.59–0.96), p = 0.02). CABG was associated with better survival outcomes than PCI in the elderly (interaction p = 0.04). Comparing OPCAB with PCI or ONCAB, propensity-score-adjusted all-cause mortality after PCI was higher than that after OPCAB (1.50 (1.20–1.86), p < 0.01). Adjusted mortality was similar between ONCAB and OPCAB (1.18 (0.93–1.51), p = 0.33). The incidence of stroke after OPCAB was similar to that after PCI (0.98 (0.71–1.34), p > 0.99), but incidence of stroke after ONCAB was higher than that after OPCAB (1.59 (1.16–2.18), p < 0.01). CONCLUSIONS In patients with multivessel and/or left main disease, CABG, particularly OPCAB, is associated with better survival outcomes than PCI using bare-metal stents. Survival outcomes are similar between ONCAB and OPCAB. PMID:21676626
Liu, Ning; Vigod, Simone N; Farrugia, M Michèle; Urquia, Marcelo L; Ray, Joel G
2018-06-08
A woman's risk of venous thromboembolism during pregnancy is estimated to be two-to-six times higher than her risk when she is not pregnant. Such risk estimates are largely based on pregnancies that result in delivery of a newborn baby; no estimates exist for the risk of venous thromboembolism after induced abortion, another common pregnancy outcome. To fill this knowledge gap, we aimed to assess the risk of venous thromboembolism in women whose first pregnancy ended with induced abortion. We did this propensity score-matched cohort study using data from the universal health-care system of Ontario, Canada. We included primigravid women who had an induced abortion between Jan 1, 2003, and Dec 31, 2015, and used a propensity score to match them to primigravid women who had a livebirth (1:1) or nulligravid women who were not pregnant on the procedure date of their matched counterpart and who did not conceive within 1 year afterwards (5:1). We excluded from our analysis women younger than 15 years or older than 49 years and individuals who had missing or invalid information about their sex, area of residence, residential income, or world region of origin. The primary outcome was risk of any venous thromboembolism within 42 days of the index date (defined as the date of an induced abortion, delivery date for livebirth, or for non-pregnant women the induced abortion date of their matched counterpart). We compared the rate of venous thromboembolism in primigravid women who had an induced abortion with the rate of venous thromboembolism in propensity-score-matched non-pregnant women and propensity-score-matched primigravid women whose pregnancy ended with a livebirth. We generated hazard ratios (HRs) of 42-day risk of venous thromboembolism after induced abortion using Cox proportional hazard models. We identified 194 086 eligible women whose first pregnancy ended with induced abortion, of whom 176 001 (90·7%) could be matched with women whose first pregnancy ended in
Kok, Victor C; Zhang, Han-Wei; Lin, Chin-Teng; Huang, Shih-Chung; Wu, Ming-Feng
2018-06-18
We hypothesized that hypertensive patients harbor a higher risk of urinary bladder (UB) cancer. We performed a population-based cohort study on adults using a National Health Insurance Research Database (NHIRD) dataset. Hypertension and comparison non-hypertensive (COMP) groups comprising 39,618 patients each were propensity score-matched by age, sex, index date, and medical comorbidities. The outcome was incident UB cancer validated using procedure codes. We constructed multivariable Cox models to derive adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Cumulative incidence was compared using a log-rank test. During a total follow-up duration of 380,525 and 372,020 person-years in the hypertension and COMP groups, 248 and 186 patients developed UB cancer, respectively, representing a 32% increase in the risk (aHR, 1.32; 95% CI, 1.09-1.60). Hypertensive women harbored a significantly increased risk of UB cancer (aHR, 1.55; 95% CI, 1.12-2.13) compared with non-hypertensive women, whereas men with hypertension had a statistically non-significant increased risk (aHR, 1.22; 95% CI, 0.96-1.55). The sensitivity analysis demonstrated that the increased risk was sustained throughout different follow-up durations for the entire cohort; a statistical increase in the risk was also noted among hypertensive men. This nationwide population-based propensity score-matched cohort study supports a positive association between hypertension and subsequent UB cancer development.
Beaudoin, Christopher E; Chen, Hongliang; Agha, Sohail
2016-01-01
Rapid population growth in Pakistan poses major risks, including those pertinent to public health. In the context of family planning in Pakistan, the current study evaluates the Touch condom media campaign and its effects on condom-related awareness, attitudes, behavioral intention, and behavior. This evaluation relies on 3 waves of panel survey data from men married to women ages 15-49 living in urban and rural areas in Pakistan (N = 1,012): Wave 1 was March 15 to April 7, 2009; Wave 2 was August 10 to August 24, 2009; and Wave 3 was May 1 to June 13, 2010. Analysis of variance provided evidence of improvements in 10 of 11 condom-related outcomes from Wave 1 to Wave 2 and Wave 3. In addition, there was no evidence of outcome decay 1 year after the conclusion of campaign advertising dissemination. To help compensate for violating the assumption of random assignment, propensity score modeling offered evidence of the beneficial effects of confirmed Touch ad recall on each of the 11 outcomes in at least 1 of 3 time-lagged scenarios. By using these different time-lagged scenarios (i.e., from Wave 1 to Wave 2, from Wave 1 to Wave 3, and from Wave 2 to Wave 3), propensity score modeling permitted insights into how the campaign had time-variant effects on the different types of condom-related outcomes, including carryover effects of the media campaign.
Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching.
Kostanyan, Tigran; Shazly, Tarek; Kaplowitz, Kevin B; Wang, Steven Z; Kola, Sushma; Brown, Eric N; Loewen, Nils A
2017-12-01
To apply propensity score matching to compare Baerveldt glaucoma drainage implant (BGI) to Trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggests that AIT can produce results similar to BGI which is traditionally reserved for more severe glaucoma. BGI and AIT patients with at least 1 year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), number of glaucoma medications, and a Glaucoma Index (GI) score. GI reflected glaucoma severity based on visual field, the number of preoperative medications, and preoperative IOP. Score matching used a genetic algorithm consisting of age, gender, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients with neovascular glaucoma, with prior glaucoma surgery, or without a close match were excluded. Of 353 patients, 30 AIT patients were matched to 29 BGI patients. Baseline characteristics including, IOP, the number of glaucoma medications, type of glaucoma, the degree of VF loss and GI were not significantly different between AIT and BGI. BGI had a preoperative IOP of 21.6 ± 6.3 mmHg compared to 21.5 ± 7.4 for AIT on 2.8 ± 1.1 medications and 2.5 ± 2.3 respectively. At 30 months, the mean IOP was 15.0 ± 3.9 mmHg for AIT versus 15.0 ± 5.7 mmHg for BGI (p > 0.05), while the number of drops was 1.5 ± 1.3 for AIT (change: p = 0.001) versus 2.4 ± 1.2 for BGI (change: p = 0.17; AIT vs BGI: 0.007). Success, defined as IOP < 21 mmHg, < 20% reduction and no reoperation, was achieved at 1 year in 56% of AIT versus 55% of BGI (p > 0.05) and 50% versus 52% at 2.5 years. A propensity score matched comparison of AIT and BGI demonstrated a similar IOP reduction through 1 year. AIT required fewer medications.
Capodanno, Davide; Caggegi, Anna; Capranzano, Piera; Cincotta, Glauco; Miano, Marco; Barrano, Gionbattista; Monaco, Sergio; Calvo, Francesco; Tamburino, Corrado
2011-06-01
The aim of this study is to verify the study hypothesis of the EXCEL trial by comparing percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) in an EXCEL-like population of patients. The upcoming EXCEL trial will test the hypothesis that left main patients with SYNTAX score ≤ 32 experience similar rates of 3-year death, myocardial infarction (MI), or cerebrovascular accidents (CVA) following revascularization by PCI or CABG. We compared the 3-year rates of death/MI/CVA and death/MI/CVA/target vessel revascularization (MACCE) in 556 patients with left main disease and SYNTAX score ≤ 32 undergoing PCI (n = 285) or CABG (n = 271). To account for confounders, outcome parameters underwent extensive statistical adjustment. The unadjusted incidence of death/MI/CVA was similar between PCI and CABG (12.7% vs. 8.4%, P = 0.892), while MACCE were higher in the PCI group compared to the CABG group (27.0% vs. 11.8%, P < 0.001). After propensity score matching, PCI was not associated with a significant increase in the rate of death/MI/CVA (11.8% vs. 10.7%, P = 0.948), while MACCE were more frequently noted among patients treated with PCI (28.8% vs. 14.1%, P = 0.002). Adjustment by means of SYNTAX score and EUROSCORE, covariates with and without propensity score, and propensity score alone did not change significantly these findings. In an EXCEL-like cohort of patients with left main disease, there seems to be a clinical equipoise between PCI and CABG in terms of death/MI/CVA. However, even in patients with SYNTAX score ≤ 32, CABG is superior to PCI when target vessel revascularization is included in the combined endpoint. Copyright © 2011 Wiley-Liss, Inc.
ERIC Educational Resources Information Center
Harder, Valerie S.; Stuart, Elizabeth A.; Anthony, James C.
2010-01-01
There is considerable interest in using propensity score (PS) statistical techniques to address questions of causal inference in psychological research. Many PS techniques exist, yet few guidelines are available to aid applied researchers in their understanding, use, and evaluation. In this study, the authors give an overview of available…
Heinrich, Sebastian; Ackermann, Andreas; Prottengeier, Johannes; Castellanos, Ixchel; Schmidt, Joachim; Schüttler, Jürgen
2015-12-01
Former analyses reported an increased rate of poor direct laryngoscopy view in cardiac surgery patients; however, these findings frequently could be attributed to confounding patient characteristics. In most of the reported cardiac surgery cohorts, the rate of well-known risk factors for poor direct laryngoscopy view such as male sex, obesity, or older age, were increased compared with the control groups. Especially in the ongoing debate on anesthesia staff qualification for cardiac interventions outside the operating room a detailed and stratified risk analysis seems necessary. Retrospective, anonymous, propensity score-based, matched-pair analysis. Single-center study in a university hospital. No active participants. Retrospective, anonymous chart analysis. The anesthesia records of patients undergoing cardiac surgery in a period of 6 consecutive years were analyzed retrospectively. The results were compared with those of a control group of patients who underwent general surgery. Poor laryngoscopic view was defined as Cormack and Lehane classification grade 3 or 4. The records of 21,561 general anesthesia procedures were reviewed for the study. The incidence of poor direct laryngoscopic views in patients scheduled for cardiac surgery was significantly increased compared with those of the general surgery cohort (7% v 4.2%). Using propensity score-based matched-pair analysis, equal subgroups were generated of each surgical department, with 2,946 patients showing identical demographic characteristics. After stratifying for demographic characteristics, the rate of poor direct laryngoscopy view remained statistically significantly higher in the cardiac surgery group (7.5% v 5.7%). Even with stratification for demographic risk factors, cardiac surgery patients showed a significantly higher rate of poor direct laryngoscopic view compared with general surgery patients. These results should be taken into account for human resource management and distribution of difficult
Büchs, Milena; Schnepf, Sylke V.
2017-01-01
Consumption surveys often record zero purchases of a good because of a short observation window. Measures of distribution are then precluded and only mean consumption rates can be inferred. We show that Propensity Score Matching can be applied to recover the distribution of consumption rates. We demonstrate the method using the UK National Travel Survey, in which c.40% of motorist households purchase no fuel. Estimated consumption rates are plausible judging by households’ annual mileages, and highly skewed. We apply the same approach to estimate CO2 emissions and outcomes of a carbon cap or tax. Reliance on means apparently distorts analysis of such policies because of skewness of the underlying distributions. The regressiveness of a simple tax or cap is overstated, and redistributive features of a revenue-neutral policy are understated. PMID:29020029
Li, Xiao-Long; Guo, Wei-Xing; Hong, Xiao-Dong; Yang, Liang; Wang, Kang; Shi, Jie; Li, Nan; Wu, Meng-Chao; Cheng, Shu-Qun
2016-10-01
The survival outcome of patients with unresectable hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) who received transarterial chemoembolization (TACE) combined with radiotherapy (RT) remains unclear. A total of 112 and 735 HCC patients with PVTT undergoing TACE combined with RT and TACE alone, respectively, were evaluated. One hundred and eight pairs of matched patients were selected from each treatment arm by using a propensity score matching (PSM) analysis. Of the whole study population, TACE combined with RT showed significant survival benefits compared with TACE in all patients (median survival, 11.0 vs 4.8 months; P < 0.001), especially in patients with PVTT involving the right/left portal vein (median survival, 12.5 vs 5.2 months; P < 0.001) and main portal vein trunk (median survival, 8.9 vs 4.3 months; P < 0.001). After one-to-one PSM, 108 pairs of matched patients were selected for further analysis. In the propensity model, the median survival time was 10.9 versus 4.1 months (P < 0.001) in all patients, 12.5 versus 4.4 months (P = 0.002) in patients with PVTT involving the right/left portal vein and 8.9 versus 4.0 months (P < 0.001) in patients with PVTT involving the main portal vein trunk. The treatment, maximum lesion diameter and main trunk PVTT were the independent prognostic factors for survival at uni- and multivariate analysis. TACE combined with RT provides a significantly better survival outcome than TACE for unresectable HCC patients with PVTT, especially for patients with PVTT involving the right/left portal vein or main trunk. © 2016 The Japan Society of Hepatology.
Bethge, M; Streibelt, M
2015-12-01
To analyze if one- and 2-year vocational retraining programs achieve similar effects on employment. Analyses were performed with longitudinal administrative data. We included persons aged 18-59 years, who started their retraining between January and June 2005. One- and 2-year program participants were matched by propensity scores. The matched groups were balanced regarding all baseline scores (one-year program: n=514; 2-year program: n=514). 4 and 5 years after start of the vocational retraining program, annual income, the duration of welfare benefits and the risk of a disability pension were comparable in both groups. However, the accumulative income between 2005 and 2009 was 9 294 Euro higher (95% CI: 3 656-14 932 Euro) in one-year retraining participants. Moreover, participants of one-year programs received less welfare benefits. The development of a vocational rehabilitation strategy needs to consider the accumulative advantage of one-year programs. © Georg Thieme Verlag KG Stuttgart · New York.
ERIC Educational Resources Information Center
Wen, Xiaoli; Leow, Christine; Hahs-Vaughn, Debbie L.; Korfmacher, Jon; Marcus, Sue M.
2012-01-01
Using data from a nationally representative sample, this study examined Head Start children's school outcome differences by the end of Kindergarten between children who attended Head Start program for two years and the ones who attended for one year. Propensity scores were used to match children who experienced different durations of the program…
Kasten, Kevin R; Celio, Adam C; Trakimas, Lauren; Manwaring, Mark L; Spaniolas, Konstantinos
2018-02-01
Surgical trainee association with operative outcomes is controversial. Studies are conflicting, possibly due to insufficient control of confounding variables such as operative time, case complexity, and heterogeneous patient populations. As operative complications worsen long-term outcomes in oncologic patients, understanding effect of trainee involvement during laparoscopic colectomy for cancer is of utmost importance. Here, we hypothesized that resident involvement was associated with worsened 30-day mortality and 30-day overall morbidity in this patient population. Patients undergoing laparoscopic colectomy for oncologic diagnosis from 2005 to 2012 were assessed using the American College of Surgeons National Surgical Quality Improvement Program dataset. Propensity score matching accounted for demographics, comorbidities, case complexity, and operative time. Attending only cases were compared to junior, middle, chief resident, and fellow level cohorts to assess primary outcomes of 30-day mortality and 30-day overall morbidity. A total of 13,211 patients met inclusion criteria, with 4075 (30.8%) cases lacking trainee involvement and 9136 (69.2%) involving a trainee. Following propensity matching, junior (PGY 1-2) and middle level (PGY 3-4) resident involvement was not associated with worsened outcomes. Chief (PGY 5) resident involvement was associated with worsened 30-day overall morbidity (15.5 vs. 18.6%, p = 0.01). Fellow (PGY > 5) involvement was associated with worsened 30-day overall morbidity (16.0 vs. 21.0%, p < 0.001), serious morbidity (9.3 vs. 13.5%, p < 0.001), minor morbidity (9.8 vs. 13.1%, p = 0.002), and surgical site infection (7.9 vs. 10.5%, p = 0.006). No differences were seen in 30-day mortality for any resident level. Following propensity-matched analysis of cancer patients undergoing laparoscopic colectomy, chief residents, and fellows were associated with worsened operative outcomes compared to attending along cases, while junior
Trygstad, Troy K; Christensen, Dale B; Wegner, Steve E; Sullivan, Rob; Garmise, Jennifer M
2009-09-01
The high cost and undesirable consequences of polypharmacy are well-recognized problems among elderly long-term care (LTC) residents. Despite the implementation of the 1987 Omnibus Budget Reconciliation Act, which requires pharmacist review of drug regimens in this setting, medical and drug costs for LTC residents have continued to increase. This study evaluates the North Carolina Long-Term Care Polypharmacy Initiative, a large-scale medication therapy management program (MTMP) that combined drug utilization review activities with drug regimen review techniques. This was a prospective records-based study that used a difference-in-difference model with both historical and nonintervention group controls. To ensure equivalence among subjects, propensity scoring was used to match study subjects from participating LTC facilities with comparison subjects from nonparticipating facilities. Residents with interventions were grouped for analysis by intervention type-retrospective only, prospective only, or dual type (residents with both prospective and retrospective interventions)-and by intervention stage-review, recommendation, and drug change-plus an all-inclusive "all types" grouping that aggregated groups by intervention type, for a total of 10 total cohorts. In the overall population of 5255 study subjects identified, a US $21.63 per member per month drug-cost savings was observed. Although only 1 of 10 cohorts had a change in the number of drug fills, substantial reductions in 2 of 5 types of drug alerts were observed in all 10 cohorts. A reduction in the relative risk for hospitalization (0.84 [95% CI, 0.71-1.00]) was observed in the cohort of residents receiving a retrospective review. This Initiative suggests that an MTMP can be quickly launched in a large number of LTC facility residents to produce monetary drug-cost savings and improved health outcomes. Additionally, the evaluation of this program illustrates the utility of using propensity scoring techniques to
ERIC Educational Resources Information Center
Stuart, Elizabeth A.; Warkentien, Siri; Jo, Booil
2011-01-01
The purpose of the current project is to explore the use of propensity scores to estimate the effects of interventions within randomized control trials, accounting for varying levels of implementation or fidelity. This work extends that of Jo and Stuart (2009) to settings with multiple or continuous measures of implementation. Rather than focus…
Borad, N P; Merchant, A M
2017-12-01
Although studies have implicated smoking as a positive predictor of post-operative outcomes in inguinal hernia repair, its impact on ventral hernia repair (VHR) is not as clear. This study aims to fill this gap by investigating the impact of smoking on developing adverse 30-day post-operative outcomes in VHR. Patients undergoing VHR between 2005 and 2014 were extracted from the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by smoking status and compared for significant differences in baseline characteristics. Logistic regression modeled the impact of smoking on the primary outcome variable of 30-day mortality and the secondary outcome variables of 30-day overall, cardiac, respiratory, or wound morbidity. To evaluate the influence of smoking in comparable groups undergoing VHR, a propensity score matched analysis was performed. Out of 169,458 patients identified, 32,973 (19.5%) were classified as current smokers. Smokers and non/ex-smokers differed significantly in multiple pre-operative baseline characteristics. Unmatched univariate analyses revealed smoking status as a positive predictor of every post-operative outcome. These findings were validated with propensity score matching analyses, which found current smokers have an increased likelihood of 30-day mortality (OR 1.42), overall morbidity (OR 1.39), wound (OR 1.40), respiratory (OR 1.14), or cardiac morbidity (OR 1.88) compared to non/ex-smokers (p < 0.05 for all). Smoking is a modifiable risk factor with a detrimental impact on outcomes in patients undergoing ventral hernia repair. Delaying VHR and promoting smoking cessation prior to surgery may help reduce the odds of adverse 30-day post-operative outcomes.
Matsue, Yuya; Shiraishi, Atsushi; Kagiyama, Nobuyuki; Yoshida, Kazuki; Kume, Teruyoshi; Okura, Hiroyuki; Suzuki, Makoto; Matsumura, Akihiko; Yoshida, Kiyoshi; Hashimoto, Yuji
2016-12-01
Although intravenous diuretics have been mainstay drugs in patients with acute heart failure (AHF), they have been suggested to have some deleterious effects on prognosis. We postulated that renal function may modify their deleterious effects in AHF patients. The study population consisted of 1094 AHF patients from three hospitals. Renal dysfunction (RD) was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m 2 on admission, and the cohort was divided into a high-dose furosemide (≥100 mg/48 h) and low-dose furosemide group according to the amount of intravenous furosemide used within 48 h from admission. In the whole cohort, in-hospital mortality rate was higher in the high-dose furosemide group than the low-dose furosemide group (12.5 vs. 6.6 %, respectively, P = 0.001). However, this difference in the in-hospital mortality rates was significant only in the RD subgroup (15.6 vs. 7.0 %, respectively, P < 0.001), and not in the non-RD subgroup (2.5 vs. 5.9 %, respectively, P = 0.384). Propensity score-matched analysis was performed to evaluate the impact of high-dose furosemide on prognosis. After propensity score matching, high-dose furosemide was not associated with in-hospital mortality (OR 1.25, 95 % CI 0.73-2.16, P = 0.408). However, there was a qualitative difference in OR for in-hospital mortality between AHF with RD (OR 1.77, 95 % CI 0.96-3.28, P = 0.068) and without RD (OR 0.23, 95 % CI 0.05-1.10, P = 0.064), and there was a significant interaction between eGFR and prognostic impact of high-dose furosemide (P for OR interaction = 0.013). An inverse relationship was observed between eGFR and OR for in-hospital death in the group treated with high-dose furosemide (decreasing OR with better eGFR). The deleterious effect of diuretics was significantly modified with renal function in AHF. This association may be one reason for poorer prognosis of AHF patients complicated with renal impairment.
Evaluating uses of data mining techniques in propensity score estimation: a simulation study.
Setoguchi, Soko; Schneeweiss, Sebastian; Brookhart, M Alan; Glynn, Robert J; Cook, E Francis
2008-06-01
In propensity score modeling, it is a standard practice to optimize the prediction of exposure status based on the covariate information. In a simulation study, we examined in what situations analyses based on various types of exposure propensity score (EPS) models using data mining techniques such as recursive partitioning (RP) and neural networks (NN) produce unbiased and/or efficient results. We simulated data for a hypothetical cohort study (n = 2000) with a binary exposure/outcome and 10 binary/continuous covariates with seven scenarios differing by non-linear and/or non-additive associations between exposure and covariates. EPS models used logistic regression (LR) (all possible main effects), RP1 (without pruning), RP2 (with pruning), and NN. We calculated c-statistics (C), standard errors (SE), and bias of exposure-effect estimates from outcome models for the PS-matched dataset. Data mining techniques yielded higher C than LR (mean: NN, 0.86; RPI, 0.79; RP2, 0.72; and LR, 0.76). SE tended to be greater in models with higher C. Overall bias was small for each strategy, although NN estimates tended to be the least biased. C was not correlated with the magnitude of bias (correlation coefficient [COR] = -0.3, p = 0.1) but increased SE (COR = 0.7, p < 0.001). Effect estimates from EPS models by simple LR were generally robust. NN models generally provided the least numerically biased estimates. C was not associated with the magnitude of bias but was with the increased SE.
Nguyen, Tri-Long; Collins, Gary S; Spence, Jessica; Daurès, Jean-Pierre; Devereaux, P J; Landais, Paul; Le Manach, Yannick
2017-04-28
Double-adjustment can be used to remove confounding if imbalance exists after propensity score (PS) matching. However, it is not always possible to include all covariates in adjustment. We aimed to find the optimal imbalance threshold for entering covariates into regression. We conducted a series of Monte Carlo simulations on virtual populations of 5,000 subjects. We performed PS 1:1 nearest-neighbor matching on each sample. We calculated standardized mean differences across groups to detect any remaining imbalance in the matched samples. We examined 25 thresholds (from 0.01 to 0.25, stepwise 0.01) for considering residual imbalance. The treatment effect was estimated using logistic regression that contained only those covariates considered to be unbalanced by these thresholds. We showed that regression adjustment could dramatically remove residual confounding bias when it included all of the covariates with a standardized difference greater than 0.10. The additional benefit was negligible when we also adjusted for covariates with less imbalance. We found that the mean squared error of the estimates was minimized under the same conditions. If covariate balance is not achieved, we recommend reiterating PS modeling until standardized differences below 0.10 are achieved on most covariates. In case of remaining imbalance, a double adjustment might be worth considering.
Dong, Nianbo; Lipsey, Mark W
2017-01-01
It is unclear whether propensity score analysis (PSA) based on pretest and demographic covariates will meet the ignorability assumption for replicating the results of randomized experiments. This study applies within-study comparisons to assess whether pre-Kindergarten (pre-K) treatment effects on achievement outcomes estimated using PSA based on a pretest and demographic covariates can approximate those found in a randomized experiment. Data-Four studies with samples of pre-K children each provided data on two math achievement outcome measures with baseline pretests and child demographic variables that included race, gender, age, language spoken at home, and mother's highest education. Research Design and Data Analysis-A randomized study of a pre-K math curriculum provided benchmark estimates of effects on achievement measures. Comparison samples from other pre-K studies were then substituted for the original randomized control and the effects were reestimated using PSA. The correspondence was evaluated using multiple criteria. The effect estimates using PSA were in the same direction as the benchmark estimates, had similar but not identical statistical significance, and did not differ from the benchmarks at statistically significant levels. However, the magnitude of the effect sizes differed and displayed both absolute and relative bias larger than required to show statistical equivalence with formal tests, but those results were not definitive because of the limited statistical power. We conclude that treatment effect estimates based on a single pretest and demographic covariates in PSA correspond to those from a randomized experiment on the most general criteria for equivalence.
Yao, Xiaoxin I; Wang, Xiaofei; Speicher, Paul J; Hwang, E Shelley; Cheng, Perry; Harpole, David H; Berry, Mark F; Schrag, Deborah; Pang, Herbert H
2017-08-01
: Propensity score (PS) analysis is increasingly being used in observational studies, especially in some cancer studies where random assignment is not feasible. This systematic review evaluates the use and reporting quality of PS analysis in oncology studies. : We searched PubMed to identify the use of PS methods in cancer studies (CS) and cancer surgical studies (CSS) in major medical, cancer, and surgical journals over time and critically evaluated 33 CS published in top medical and cancer journals in 2014 and 2015 and 306 CSS published up to November 26, 2015, without earlier date limits. The quality of reporting in PS analysis was evaluated. It was also compared over time and among journals with differing impact factors. All statistical tests were two-sided. More than 50% of the publications with PS analysis from the past decade occurred within the past two years. Of the studies critically evaluated, a considerable proportion did not clearly provide the variables used to estimate PS (CS 12.1%, CSS 8.8%), incorrectly included non baseline variables (CS 3.4%, CSS 9.3%), neglected the comparison of baseline characteristics (CS 21.9%, CSS 15.6%), or did not report the matching algorithm utilized (CS 19.0%, CSS 36.1%). In CSS, the reporting of the matching algorithm improved in 2014 and 2015 ( P = .04), and the reporting of variables used to estimate PS was better in top surgery journals ( P = .008). However, there were no statistically significant differences for the inclusion of non baseline variables and reporting of comparability of baseline characteristics. The use of PS in cancer studies has dramatically increased recently, but there is substantial room for improvement in the quality of reporting even in top journals. Herein we have proposed reporting guidelines for PS analyses that are broadly applicable to different areas of medical research that will allow better evaluation and comparison across studies applying this approach. © The Author 2017
Barth, Richard P; Greeson, Johanna K P; Guo, Shenyang; Green, Rebecca L; Hurley, Sarah; Sisson, Jocelyn
2007-10-01
This study compares outcomes for behaviorally troubled children receiving intensive in-home therapy (IIHT) and those receiving residential care (RC). Propensity score matching is used to identify matched pairs of youth (n = 786) with equivalent propensity for IIHT. The majority of pretreatment differences between the IIHT and RC groups are eliminated following matching. Logistic regression is then conducted on outcome differences at 1 year postdischarge. Results show that IIHT recipients had a greater tendency (.615) toward living with family, making progress in school, not experiencing trouble with the law, and placement stability compared with RC youth (.558; p < .10). This suggests that IIHT is at least as effective for achieving positive outcomes. Given IIHT's reduced restrictiveness and cost, intensive in-home services should be the preferred treatment over RC in most cases.
Chiu, Kuan M; Chen, Robert J; Lin, Tzu Y; Chen, Jer S; Huang, Jin H; Huang, Chun Y; Chu, Shu H
2016-02-01
Limited real-world data existed for mini-parasternotomy approach with good sample size in Asian cohorts and most previous studies were eclipsed by case heterogeneity. The goal of this study was to compare safety and quality outcomes of cardiac non-coronary valve operations by mini-parasternotomy and full sternotomy approaches on risk-adjusted basis. METHODS From our hospital database, we retrieved the cases of non-coronary valve operations from 1 January 2005 to 31 December 2012, including re-do, emergent, and combined procedures. Estimated EuroScore-II and propensity score for choosing mini-parasternotomy were adjusted for in the regression models on hospital mortality, complications (pneumonia, stroke, sepsis, etc.), and quality parameters (length of stay, ICU time, ventilator time, etc.). Non-complicated cases, defined as survival to discharge, ventilator use not over one week, and intensive care unit stay not over two weeks, were used for quality parameters. There were 283 mini-parasternotomy and 177 full sternotomy cases. EuroScore-II differed significantly (medians 2.1 vs. 4.7, P<0.001). Propensity scores for choosing mini-parasternotomy were higher with lower EuroScore-II (OR=0.91 per 1%, P<0.001), aortic regurgitation (OR=2.3, P=0.005), and aortic non-mitral valve disease (OR=3.9, P<0.001). Adjusted for propensity score and EuroScore-II, mini-parasternotomy group had less pneumonia (OR=0.32, P=0.043), less sepsis (OR=0.31, P=0.045), and shorter non-complicated length of stay (coefficient=-7.2 (day), P<0.001) than full sternotomy group, whereas Kaplan-Meier survival, non-complicated ICU time, non-complicated ventilator time, and 30-day mortality did not differ significantly. The propensity-adjusted analysis demonstrated encouraging safety and quality outcomes for mini-parasternotomy valve operation in carefully selected patients.
Cuervo, Guillermo; Garcia-Vidal, Carolina; Puig-Asensio, Mireia; Vena, Antonio; Meije, Yolanda; Fernández-Ruiz, Mario; González-Barberá, Eva; Blanco-Vidal, María José; Manzur, Adriana; Cardozo, Celia; Gudiol, Carlota; Montejo, José Miguel; Pemán, Javier; Ayats, Josefina; Aguado, Jose María; Muñoz, Patricia; Marco, Francesc; Almirante, Benito; Carratalà, Jordi
2017-05-15
Whether echinocandins could be used to treat candidemia of a urinary tract source (CUTS) is unknown. We aimed to provide current epidemiological information of CUTS and to compare echinocandin to fluconazole treatment on CUTS outcomes. A multicenter study of adult patients with candidemia was conducted in 9 hospitals. CUTS was defined as a candidemia with concomitant candiduria by the same organism associated with significant urological comorbidity. The primary outcome assessed was clinical failure (defined by 7-day mortality or persistent candidemia) in patients treated with either an echinocandin or fluconazole. A propensity score was calculated and then entered into a regression model. Of 2176 episodes of candidemia, 128 were CUTS (5.88%). Most CUTS cases were caused by Candida albicans (52.7%), followed by Candida glabrata (25.6%) and Candida tropicalis (16.3%). Clinical failure occurred in 7 patients (20%) treated with an echinocandin and in 15 (17.1%) treated with fluconazole (P = .730). Acute renal failure (adjusted odds ratio [AOR], 3.01; 95% confidence interval [CI], 1.01-8.91; P = .047) was the only independent factor associated with clinical failure, whereas early urinary tract drainage procedures (surgical, percutaneous, or endoscopic) were identified as protective (AOR, 0.08; 95% CI, .02-.31; P < .001). Neither univariate nor multivariate analysis showed that echinocandin therapy altered the risk of clinical failure. Initial echinocandin therapy was not associated with clinical failure in patients with CUTS. Notably, acute renal failure predicted worse outcomes and performing an early urologic procedure was a protective measure. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com
Lonjon, Guillaume; Porcher, Raphael; Ergina, Patrick; Fouet, Mathilde; Boutron, Isabelle
2017-05-01
To describe the evolution of the use and reporting of propensity score (PS) analysis in observational studies assessing a surgical procedure. Assessing surgery in randomized controlled trials raises several challenges. Observational studies with PS analysis are a robust alternative for comparative effectiveness research. In this methodological systematic review, we identified all PubMed reports of observational studies with PS analysis that evaluated a surgical procedure and described the evolution of their use over time. Then, we selected a sample of articles published from August 2013 to July 2014 and systematically appraised the quality of reporting and potential bias of the PS analysis used. We selected 652 reports of observational studies with PS analysis. The publications increased over time, from 1 report in 1987 to 198 in 2013. Among the 129 reports assessed, 20% (n = 24) did not detail the covariates included in the PS and 77% (n = 100) did not report a justification for including these covariates in the PS. The rate of missing data for potential covariates was reported in 9% of articles. When a crossover by conversion was possible, only 14% of reports (n = 12) mentioned this issue. For matched analysis, 10% of articles reported all 4 key elements that allow for reproducibility of a PS-matched analysis (matching ratio, method to choose the nearest neighbors, replacement and method for statistical analysis). Observational studies with PS analysis in surgery are increasing in frequency, but specific methodological issues and weaknesses in reporting exist.
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.
Stürmer, Til; Joshi, Manisha; Glynn, Robert J.; Avorn, Jerry; Rothman, Kenneth J.; Schneeweiss, Sebastian
2006-01-01
Objective Propensity score analyses attempt to control for confounding in non-experimental studies by adjusting for the likelihood that a given patient is exposed. Such analyses have been proposed to address confounding by indication, but there is little empirical evidence that they achieve better control than conventional multivariate outcome modeling. Study design and methods Using PubMed and Science Citation Index, we assessed the use of propensity scores over time and critically evaluated studies published through 2003. Results Use of propensity scores increased from a total of 8 papers before 1998 to 71 in 2003. Most of the 177 published studies abstracted assessed medications (N=60) or surgical interventions (N=51), mainly in cardiology and cardiac surgery (N=90). Whether PS methods or conventional outcome models were used to control for confounding had little effect on results in those studies in which such comparison was possible. Only 9 out of 69 studies (13%) had an effect estimate that differed by more than 20% from that obtained with a conventional outcome model in all PS analyses presented. Conclusions Publication of results based on propensity score methods has increased dramatically, but there is little evidence that these methods yield substantially different estimates compared with conventional multivariable methods. PMID:16632131
Liao, Xing; Xie, Yan-ming
2014-10-01
The impact of evidence-based medicine and clinical epidemiology on clinical research has contributed to the development of Chinese medicine in modern times over the past two decades. Many concepts and methods of modern science and technology are emerging in Chinese medicine research, resulting in constant progress. Systematic reviews, randomized controlled trials and other advanced mathematic approaches and statistical analysis methods have brought reform to Chinese medicine. In this new era, Chinese medicine researchers have many opportunities and challenges. On the one hand, Chinese medicine researchers need to dedicate themselves to providing enough evidence to the world through rigorous studies, whilst on the other hand, they also need to keep up with the speed of modern medicine research. For example, recently, real world study, comparative effectiveness research, propensity score techniques and registry study have emerged. This article aims to inspire Chinese medicine researchers to explore new areas by introducing these new ideas and new techniques.
Tam, Vernissia; Luketich, James D; Winger, Daniel G; Sarkaria, Inderpal S; Levy, Ryan M; Christie, Neil A; Awais, Omar; Shende, Manisha R; Nason, Katie S
2017-01-01
Patients undergoing non-elective paraesophageal hernia repair (PEHR) have worse perioperative outcomes. Because they are usually older and sicker, however, these patients may be more prone to adverse events, independent of surgical urgency. Our study aimed to determine whether non-elective PEHR is associated with differential postoperative outcome compared to elective repair, using propensity-score weighting. We abstracted data for patients undergoing PEHR (n = 924; non-elective n = 171 (19 %); 1997-2010). Using boosted regression, we generated a propensity-weighted dataset. Odds of 30-day/in-hospital mortality and major complications after non-elective surgery were determined. Patients undergoing non-elective repair were significantly older, had more adverse prognostic factors, and significantly more major complications (38 versus 18 %; p < 0.001) and death (8 versus 1 %; p < 0.001). After propensity weighting, median absolute percentage bias across 28 propensity-score variables improved from 19 % (significant imbalance) to 5.6 % (well-balanced). After adjusting propensity-weighted data for age and comorbidity score, odds of major complications were still nearly two times greater (OR 1.67, CI 1.07-2.61) and mortality nearly three times greater (OR 2.74, CI 0.93-8.1) than for elective repair. Even after balancing significant differences in baseline characteristics, non-elective PEHR was associated with worse outcomes than elective repair. Symptomatic patients should be referred for elective repair by experienced surgeons.
Bevilacqua, Elisa; Jani, Jacques C; Letourneau, Alexandra; Duiella, Silvia F; Kleinfinger, Pascale; Lohmann, Laurence; Resta, Serena; Cos Sanchez, Teresa; Fils, Jean-François; Mirra, Marilyn; Benachi, Alexandra; Costa, Jean-Marc
2018-06-13
To evaluate the failure rate and performance of cell-free DNA (cfDNA) testing, mainly in terms of detection rates for trisomy 21, performed by 2 laboratories using different analytical methods. cfDNA testing was performed on 2,870 pregnancies with the HarmonyTM Prenatal Test using the targeted digital analysis of selected regions (DANSR) method, and on 2,635 pregnancies with the "Cerba test" using the genome-wide massively parallel sequencing (GW-MPS) method, with available outcomes. Propensity score analysis was used to match patients between the 2 groups. A comparison of the detection rates for trisomy 21 between the 2 laboratories was made. In all, 2,811 patients in the Harmony group and 2,530 patients in the Cerba group had no trisomy 21, 18, or 13. Postmatched comparisons of the patient characteristics indicated a higher no-result rate in the Harmony group (1.30%) than in the Cerba group (0.75%; p = 0.039). All 41 cases of trisomy 21 in the Harmony group and 93 cases in the Cerba group were detected. Both methods of cfDNA testing showed low no-result rates and a comparable performance in detecting trisomy 21; yet GW-MPS had a slightly lower no-result rate than the DANSR method. © 2018 S. Karger AG, Basel.
Zhang, Hui; Wang, Yang; Jiang, Zhu-Ming; Kondrup, Jens; Fang, Hai; Andrews, Martha; Nolan, Marie T; Mu, Shao-Yu; Zhang, Jun; Yu, Kang; Lu, Qian; Kang, Wei-Ming
2017-05-01
There is a lack of evidence regarding the economic effects of nutrition support in patients at nutritional risk. The aim of this study was to perform a cost-effectiveness analysis by comparing an adequate nutrition support cohort with a no-support cohort. A prospective observational study was performed in the surgical and medical gastroenterology wards. We identified patients at nutritional risk and the provision of nutrition support by the staff, unaware of the risk status, was recorded. Cost data were obtained from each patient's statement of accounts, and effectiveness was measured by the rate of infectious complication. To control for potential confounding variables, the propensity score method with matching was carried out. The incremental cost-effectiveness ratio was calculated based on the matched population. We screened 3791 patients, and 440 were recruited for the analysis. Patients in the nutrition support cohort had a lower incidence of infectious complications than those in the no-support cohort (9.1 versus 18.1%; P = 0.007). This result was similar in the 149 propensity matched pairs (9.4 versus 24.2%; P < 0.001). The median hospital length of stay was significantly reduced among the matched nutrition support patients (13 versus 15 d; P < 0.001). The total costs were similar among the matched pairs (US $6219 versus $6161). The incremental cost-effectiveness analysis suggested that nutrition support cost US $392 per patient prevented from having infectious complications. Nutrition support was associated with fewer infectious complications and shorter length of stay in patients at nutritional risk. The incremental cost-effectiveness ratio indicated that nutrition support had not increased costs significantly. Copyright © 2016 Elsevier Inc. All rights reserved.
Taking the Missing Propensity Into Account When Estimating Competence Scores
Pohl, Steffi; Carstensen, Claus H.
2014-01-01
When competence tests are administered, subjects frequently omit items. These missing responses pose a threat to correctly estimating the proficiency level. Newer model-based approaches aim to take nonignorable missing data processes into account by incorporating a latent missing propensity into the measurement model. Two assumptions are typically made when using these models: (1) The missing propensity is unidimensional and (2) the missing propensity and the ability are bivariate normally distributed. These assumptions may, however, be violated in real data sets and could, thus, pose a threat to the validity of this approach. The present study focuses on modeling competencies in various domains, using data from a school sample (N = 15,396) and an adult sample (N = 7,256) from the National Educational Panel Study. Our interest was to investigate whether violations of unidimensionality and the normal distribution assumption severely affect the performance of the model-based approach in terms of differences in ability estimates. We propose a model with a competence dimension, a unidimensional missing propensity and a distributional assumption more flexible than a multivariate normal. Using this model for ability estimation results in different ability estimates compared with a model ignoring missing responses. Implications for ability estimation in large-scale assessments are discussed. PMID:29795844
Polinski, Jennifer M.; Schneeweiss, Sebastian; Glynn, Robert J.; Lii, Joyce; Rassen, Jeremy
2012-01-01
Purpose Under Medicare Part D, patient characteristics influence plan choice, which in turn influences Part D coverage gap entry. We compared pre-defined propensity score (PS) and high-dimensional propensity score (hdPS) approaches to address such ‘confounding by health system use’ in assessing whether coverage gap entry is associated with cardiovascular events or death. Methods We followed 243,079 Medicare patients aged 65+ with linked prescription, medical, and plan-specific data in 2005–2007. Patients reached the coverage gap and were followed until an event or year’s end. Exposed patients were responsible for drug costs in the gap; unexposed patients (patients with non-Part D drug insurance and Part D patients receiving a low-income subsidy (LIS)) received financial assistance. Exposed patients were 1:1 PS- or hdPS-matched to unexposed patients. The PS model included 52 predefined covariates; the hdPS model added 400 empirically identified covariates. Hazard ratios for death and any of five cardiovascular outcomes were compared. In sensitivity analyses, we explored residual confounding using only LIS patients in the unexposed group. Results In unadjusted analyses, exposed patients had no greater hazard of death (HR=1.00; 95% CI, 0.84–1.20) or other outcomes. PS- (HR=1.29;0.99–1.66) and hdPS- (HR=1.11;0.86–1.42) matched analyses showed elevated but non-significant hazards of death. In sensitivity analyses, the PS analysis showed a protective effect (HR=0.78;0.61–0.98), while the hdPS analysis (HR=1.06;0.82–1.37) confirmed the main hdPS findings. Conclusion Although the PS-matched analysis suggested elevated though non-significant hazards of death among patients with no financial assistance during the gap, the hdPS analysis produced lower estimates that were stable across sensitivity analyses. PMID:22552984
Chiu, K M; Chen, R J; Lin, T Y; Chen, J S; Huang, J H; Huang, C Y; Chu, S H
2014-03-26
Limited realworld data existed for miniparasternotomy approach with good sample size in Asian cohorts and most previous studies were eclipsed by case heterogeneity. The goal of this study was to compare safety and quality outcomes of cardiac noncoronary valve operations by miniparasternotomy and full sternotomy approaches on riskadjusted basis. From our hospital database, we retrieved the cases of non-coronary valve operations from 1 January 2005 to 31 December 2012, including re-do, emergent, and combined procedures. Estimated EuroScore-II and propensity score for choosing mini-parasternotomy were adjusted for in the regression models on hospital mortality, complications (pneumonia, stroke, sepsis, etc.), and quality parameters (length of stay, ICU time, ventilator time, etc.). Non-complicated cases, defined as survival to discharge, ventilator use not over one week, and intensive care unit stay not over two weeks, were used for quality parameters. There were 283 miniparasternotomy and 177 full sternotomy cases. EuroScore-II differed significantly (medians 2.1 vs. 4.7, p<0.001). Propensity scores for choosing miniparasternotomy were higher with lower EuroScore-II (OR=0.91 per 1%, p<0.001), aortic regurgitation (OR=2.3, p=0.005), and aortic non-mitral valve disease (OR=3.9, p<0.001). Adjusted for propensity score and EuroScore-II, mini-parasternotomy group had less pneumonia (OR=0.32, p=0.043), less sepsis (OR=0.31, p=0.045), and shorter non-complicated length of stay (coefficient=7.2 (day), p<0.001) than full sternotomy group, whereas Kaplan-Meier survival, non-complicated ICU time, non-complicated ventilator time, and 30-day mortality did not differ significantly. The propensity-adjusted analysis demonstrated encouraging safety and quality outcomes for mini-parasternotomy valve operation in carefully selected patients.
ERIC Educational Resources Information Center
Thomas, Ally S.; Bonner, Sarah M.; Everson, Howard T.
2014-01-01
Recently, the authors have been exploring the use of propensity score methods for developing evidence of program impact. Specifically, they have been developing evidence (after one year of implementation) of the effects of the Math Science Partnership in New York City ("MSPinNYC2") on high school students' achievement--both in terms of…
Lewin, Joel W.; O'Rourke, Nicholas A.; Chiow, Adrian K.H.; Bryant, Richard; Martin, Ian; Nathanson, Leslie K.; Cavallucci, David J.
2015-01-01
Background This study compares long-term outcomes between intention-to-treat laparoscopic and open approaches to colorectal liver metastases (CLM), using inverse probability of treatment weighting (IPTW) based on propensity scores to control for selection bias. Method Patients undergoing liver resection for CLM by 5 surgeons at 3 institutions from 2000 to early 2014 were analysed. IPTW based on propensity scores were generated and used to assess the marginal treatment effect of the laparoscopic approach via a weighted Cox proportional hazards model. Results A total of 298 operations were performed in 256 patients. 7 patients with planned two-stage resections were excluded leaving 284 operations in 249 patients for analysis. After IPTW, the population was well balanced. With a median follow up of 36 months, 5-year overall survival (OS) and recurrence-free survival (RFS) for the cohort were 59% and 38%. 146 laparoscopic procedures were performed in 140 patients, with weighted 5-year OS and RFS of 54% and 36% respectively. In the open group, 138 procedures were performed in 122 patients, with a weighted 5-year OS and RFS of 63% and 38% respectively. There was no significant difference between the two groups in terms of OS or RFS. Conclusion In the Brisbane experience, after accounting for bias in treatment assignment, long term survival after LLR for CLM is equivalent to outcomes in open surgery. PMID:26902138
Wu, Chueh-Hung; Chen, Li-Sheng; Yen, Ming-Fang; Chiu, Yueh-Hsia; Fann, Ching-Yuan; Chen, Hsiu-Hsi; Pan, Shin-Liang
2014-01-01
Previous studies on the association between tuberculosis and the risk of developing ischemic stroke have generated inconsistent results. We therefore performed a population-based, propensity score-matched longitudinal follow-up study to investigate whether contracting non-central nervous system (CNS) tuberculosis leads to an increased risk of ischemic stroke. We used a logistic regression model that includes age, sex, pre-existing comorbidities and socioeconomic status as covariates to compute the propensity score. A total of 5804 persons with at least three ambulatory visits in 2001 with the principal diagnosis of non-CNS tuberculosis were enrolled in the tuberculosis group. The non-tuberculosis group consisted of 5804, propensity score-matched subjects without tuberculosis. The three-year ischemic stroke-free survival rates for these 2 groups were estimated using the Kaplan-Meier method. The stratified Cox proportional hazards regression was used to estimate the effect of tuberculosis on the occurrence of ischemic stroke. During three-year follow-up, 176 subjects in the tuberculosis group (3.0%) and 207 in the non-tuberculosis group (3.6%) had ischemic stroke. The hazard ratio for developing ischemic stroke in the tuberculosis group was 0.92 compared to the non-tuberculosis group (95% confidence interval: 0.73-1.14, P = 0.4299). Non-CNS tuberculosis does not increase the risk of subsequent ischemic stroke.
Zhao, Huaqing; Rebbeck, Timothy R; Mitra, Nandita
2009-12-01
Confounding due to population stratification (PS) arises when differences in both allele and disease frequencies exist in a population of mixed racial/ethnic subpopulations. Genomic control, structured association, principal components analysis (PCA), and multidimensional scaling (MDS) approaches have been proposed to address this bias using genetic markers. However, confounding due to PS can also be due to non-genetic factors. Propensity scores are widely used to address confounding in observational studies but have not been adapted to deal with PS in genetic association studies. We propose a genomic propensity score (GPS) approach to correct for bias due to PS that considers both genetic and non-genetic factors. We compare the GPS method with PCA and MDS using simulation studies. Our results show that GPS can adequately adjust and consistently correct for bias due to PS. Under no/mild, moderate, and severe PS, GPS yielded estimated with bias close to 0 (mean=-0.0044, standard error=0.0087). Under moderate or severe PS, the GPS method consistently outperforms the PCA method in terms of bias, coverage probability (CP), and type I error. Under moderate PS, the GPS method consistently outperforms the MDS method in terms of CP. PCA maintains relatively high power compared to both MDS and GPS methods under the simulated situations. GPS and MDS are comparable in terms of statistical properties such as bias, type I error, and power. The GPS method provides a novel and robust tool for obtaining less-biased estimates of genetic associations that can consider both genetic and non-genetic factors. 2009 Wiley-Liss, Inc.
Krishna, Somashekar G; Rawal, Varun; Durkin, Claire; Modi, Rohan M; Hinton, Alice; Cruz-Monserrate, Zobeida; Conwell, Darwin L; Hussan, Hisham
2018-06-21
There is a lack of population studies evaluating the impact of bariatric surgery (BRS) on all-cause inpatient mortality. We sought to determine the impact of prior BRS on all-cause mortality and healthcare utilization in hospitalized patients. We analyzed the National Inpatient Sample database from 2007 to 2013. Participants were adult (≥ 18 years) inpatients admitted with a diagnosis of morbid obesity or a history of BRS. Propensity score-matched analyses were performed to compare mortality and healthcare resource utilization (hospital length of stay and cost). There were 9,044,103 patient admissions with morbid obesity and 1,066,779 with prior BRS. A propensity score-matched cohort analysis demonstrated that prior BRS was associated with decreased mortality (OR = 0.58; 95% CI [0.54, 0.63]), shorter length of stay (0.59 days; P < 0.001), and lower hospital costs ($2152; P < 0.001) compared to morbid obesity. A subgroup of propensity score-matched analysis among patients with high-risk of mortality (leading ten causes of mortality in morbid obesity) revealed a consistently significant reduction in odds of mortality for patients with prior BRS (OR = 0.82; 95% CI [0.72, 0.92]). Hospitalized patients with a history of BRS have lower all-cause mortality and healthcare resource utilization compared to those who are morbidly obese. These observations support the continued application of BRS as an effective and resource-conscious treatment for morbid obesity.
Sahota, Shawn; Lovecchio, Francis; Harold, Ryan E; Beal, Matthew D; Manning, David W
2018-01-01
Total joint arthroplasty (TJA) is a highly successful treatment, but is burdensome to the national healthcare budget. National quality initiatives seek to reduce costly complications. Smoking's role in perioperative complication after TJA is less well known. This study aims to identify smoking's independent contribution to the risk of short-term complication after TJA. All patients undergoing primary TJA between 2011 and 2012 were selected from the American College of Surgeon's National Surgical Quality Improvement Program's database. Outcomes of interest included rates of readmission, reoperation, mortality, surgical complications, and medical complications. To eliminate confounders between smokers and nonsmokers, a propensity score was used to generate a 1:1 match between groups. A total of 1251 smokers undergoing TJA met inclusion criteria. Smokers in the combined total hip and knee arthroplasty cohort had higher 30-day readmission (4.8% vs 3.2%, P = .041), were more likely to have a surgical complication (odds ratio 1.84, 95% confidence interval 1.21-2.80), and had a higher rate of deep surgical site infection (SSI) (1.1% vs 0.2%, P = .007). Analysis of total hip arthroplasty only revealed that smokers had higher rates of deep SSI (1.3% vs 0.2%, P = .038) and higher readmission rate (4.3% vs 2.2%, P = .034). Analysis of total knee arthroplasty only revealed greater surgical complications (2.8% vs 1.2%, P = .048) and superficial SSI (1.8% vs 0.2%, P = .002) in smokers. Smoking in TJA is associated with higher rates of SSI, surgical complications, and readmission. Copyright © 2017 Elsevier Inc. All rights reserved.
Lee, O H; Choi, G J; Kang, H; Baek, C W; Jung, Y H; Woo, Y C; Oh, J; Park, Y H
2017-01-01
Sugammadex is a new agent that reverses neuromuscular blockade by aminosteroid neuromuscular blocker. This retrospective study compared the effects of sugammadex on post-operative nausea and vomiting (PONV) with those of a pyridostigmine-glycopyrrolate mixture. We reviewed the electronic medical records of 7179 patients who had received fentanyl-based, intravenous, patient-controlled analgesia (IV-PCA) at Chung-Ang University Hospital between January 1, 2010 and December 31, 2015. We categorized the patients into two groups on the basis of the type of reversal agent to neuromuscular blockade that was used: a traditional reversal agent (pyridostigmine-glycopyrrolate mixture; Group R; n = 7059) and sugammadex (Group S; n = 120). The propensity score matching method was then used to select 408 subjects in Group R and 115 subjects in Group S; on the basis of their covariates, these subjects were then matched with a counterpart in the other group. After propensity score matching, the two groups were well balanced with respect to all baseline covariates. In Group S, the numeric rating scale of nausea on day 0, as well as the number of patients who vomited on day 0, was lower than that in group R. Furthermore, Group S used fewer rescue antiemetics on day 0 and had a higher complete response on day 0. Sugammadex might be more beneficial for PONV compared to pyridostigmine-glycopyrrolate mixture for patients who have received opioid-based IV-PCA. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.
Kim, O-S; Kim, M S; Lee, J E; Jung, H
2016-12-01
The prevalence of night-eating syndrome (NES) and depression is increasing worldwide. Although nurses, in particular, are exposed to work in an environment of irregular eating, shift work, and stressful settings, limited research exist. In fact, the prevalence of NES among Korean nurses has never been reported. The aim of this study was to determine the prevalence of NES as well as the association between NES and severity of self-reported depressive symptoms among South Korean female nurses. The Korea Nurses' Health Study, following the protocols of the Nurses' Health Study led by the Harvard University, collected data on Korean female nurses. Survey responses from 3617 participants were included, and 404 responses were analyzed in this cross-sectional study using propensity score matching. Descriptive, Spearman's and Cramer's correlations, propensity score matching, and multivariable ordinal logistic regression were conducted as statistical analysis. The prevalence of both NES and self-reported depressive symptoms among Korean female nurses were higher compared with nurses in prior studies. Nurses with NES were 1.65 times more likely to have greater severity of depressive symptoms than those without NES (95% confidence interval [1.19-2.10], odds ratio = 1.65) after adjusting for covariates including sociodemographic characteristics, health behavioural factors, and shift work. This study suggests significant association between NES and the severity of self-reported depressive symptoms among Korean female nurses after adjusting for covariates. Policy makers and hospital managers need to develop strategies to reduce depression and NES among nurses for enhancement of nurses' mental and physical health as well as for improvement of care quality. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
Facciorusso, Antonio; Di Maso, Marianna; Antonino, Matteo; Del Prete, Valentina; Panella, Carmine; Barone, Michele; Muscatiello, Nicola
2015-08-01
EMR is the standard of care for the resection of large polyps. To compare the efficacy and safety profile of submucosal polidocanol injection with epinephrine-saline solution injection for colon polypectomy with a diathermic snare. After 1-to-1 propensity score caliper matching, comparison of submucosal epinephrine injection was performed with polidocanol injection. Endoscopic suite at the University of Foggia between 2005 and 2014. Of 711 patients who underwent endoscopic resection of colon sessile polyps 20 mm or larger, 612 were analyzed after matching. Submucosal epinephrine injection in 306 patients and polidocanol injection in 306 patients. Univariate and multivariate logistic regression models aimed at identifying independent predictors of postpolypectomy bleeding (PPB). The 2 groups presented similar baseline clinical parameters and lesion characteristics. All patients had a single polyp 20 mm or larger; the median size was 32 mm (interquartile range [IQR], 25-38) in the polidocanol group and 32 (IQR, 24-38) in the epinephrine group (P=.7). Polidocanol was more effective in preventing both immediate and delayed PPB (P<.001 and P=.003, respectively), and its efficacy was confirmed in almost all of the subgroups, regardless of polyp size and histology. Postprocedure perforation was observed in 2 patients (0.3%), both in the epinephrine group (P=.49). The 2 groups did not differ in the number of snare resections of lesions or the procedure duration (P=.24 and .6, respectively). Absence of randomization. The submucosal injection of polidocanol for colon EMR is effective and significantly lowers the PPB rate. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.
TAP score: torsion angle propensity normalization applied to local protein structure evaluation
Tosatto, Silvio CE; Battistutta, Roberto
2007-01-01
Background Experimentally determined protein structures may contain errors and require validation. Conformational criteria based on the Ramachandran plot are mainly used to distinguish between distorted and adequately refined models. While the readily available criteria are sufficient to detect totally wrong structures, establishing the more subtle differences between plausible structures remains more challenging. Results A new criterion, called TAP score, measuring local sequence to structure fitness based on torsion angle propensities normalized against the global minimum and maximum is introduced. It is shown to be more accurate than previous methods at estimating the validity of a protein model in terms of commonly used experimental quality parameters on two test sets representing the full PDB database and a subset of obsolete PDB structures. Highly selective TAP thresholds are derived to recognize over 90% of the top experimental structures in the absence of experimental information. Both a web server and an executable version of the TAP score are available at . Conclusion A novel procedure for energy normalization (TAP) has significantly improved the possibility to recognize the best experimental structures. It will allow the user to more reliably isolate problematic structures in the context of automated experimental structure determination. PMID:17504537
Lewin, Joel W; O'Rourke, Nicholas A; Chiow, Adrian K H; Bryant, Richard; Martin, Ian; Nathanson, Leslie K; Cavallucci, David J
2016-02-01
This study compares long-term outcomes between intention-to-treat laparoscopic and open approaches to colorectal liver metastases (CLM), using inverse probability of treatment weighting (IPTW) based on propensity scores to control for selection bias. Patients undergoing liver resection for CLM by 5 surgeons at 3 institutions from 2000 to early 2014 were analysed. IPTW based on propensity scores were generated and used to assess the marginal treatment effect of the laparoscopic approach via a weighted Cox proportional hazards model. A total of 298 operations were performed in 256 patients. 7 patients with planned two-stage resections were excluded leaving 284 operations in 249 patients for analysis. After IPTW, the population was well balanced. With a median follow up of 36 months, 5-year overall survival (OS) and recurrence-free survival (RFS) for the cohort were 59% and 38%. 146 laparoscopic procedures were performed in 140 patients, with weighted 5-year OS and RFS of 54% and 36% respectively. In the open group, 138 procedures were performed in 122 patients, with a weighted 5-year OS and RFS of 63% and 38% respectively. There was no significant difference between the two groups in terms of OS or RFS. In the Brisbane experience, after accounting for bias in treatment assignment, long term survival after LLR for CLM is equivalent to outcomes in open surgery. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.
Xu, Ronghui; Hou, Jue; Chambers, Christina D
2018-06-01
Our work was motivated by small cohort studies on the risk of birth defects in infants born to pregnant women exposed to medications. We controlled for confounding using propensity scores (PS). The extremely rare events setting renders the matching or stratification infeasible. In addition, the PS itself may be formed via different approaches to select confounders from a relatively long list of potential confounders. We carried out simulation experiments to compare different combinations of approaches: IPW or regression adjustment, with 1) including all potential confounders without selection, 2) selection based on univariate association between the candidate variable and the outcome, 3) selection based on change in effects (CIE). The simulation showed that IPW without selection leads to extremely large variances in the estimated odds ratio, which help to explain the empirical data analysis results that we had observed. Copyright © 2018 Elsevier Inc. All rights reserved.
Rau, Cheng-Shyuan; Wu, Shao-Chun; Kuo, Pao-Jen; Chen, Yi-Chun; Chien, Peng-Chen; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua
2017-09-11
Background: Polytrauma patients are expected to have a higher risk of mortality than that obtained by the summation of expected mortality owing to their individual injuries. This study was designed to investigate the outcome of patients with polytrauma, which was defined using the new Berlin definition, as cases with an Abbreviated Injury Scale (AIS) ≥ 3 for two or more different body regions and one or more additional variables from five physiologic parameters (hypotension [systolic blood pressure ≤ 90 mmHg], unconsciousness [Glasgow Coma Scale score ≤ 8], acidosis [base excess ≤ -6.0], coagulopathy [partial thromboplastin time ≥ 40 s or international normalized ratio ≥ 1.4], and age [≥70 years]). Methods: We retrieved detailed data on 369 polytrauma patients and 1260 non-polytrauma patients with an overall Injury Severity Score (ISS) ≥ 18 who were hospitalized between 1 January 2009 and 31 December 2015 for the treatment of all traumatic injuries, from the Trauma Registry System at a level I trauma center. Patients with burn injury or incomplete registered data were excluded. Categorical data were compared with two-sided Fisher exact or Pearson chi-square tests. The unpaired Student t -test and the Mann-Whitney U -test was used to analyze normally distributed continuous data and non-normally distributed data, respectively. Propensity-score matched cohort in a 1:1 ratio was allocated using the NCSS software with logistic regression to evaluate the effect of polytrauma on patient outcomes. Results: The polytrauma patients had a significantly higher ISS than non-polytrauma patients (median (interquartile range Q1-Q3), 29 (22-36) vs. 24 (20-25), respectively; p < 0.001). Polytrauma patients had a 1.9-fold higher odds of mortality than non-polytrauma patients (95% CI 1.38-2.49; p < 0.001). Compared to non-polytrauma patients, polytrauma patients had a substantially longer hospital length of stay (LOS). In addition, a higher proportion of polytrauma
Elstad, Jon Ivar; Pedersen, Axel West
2012-01-01
Studies have revealed that relative poverty is associated with ill health, but the interpretations of this correlation vary. This article asks whether relative poverty among Norwegian adolescents is causally related to poor subjective health, i.e., self-reported somatic and mental symptoms. Data consist of interview responses from a sample of adolescents (N = 510) and their parents, combined with register data on the family’s economic situation. Relatively poor adolescents had significantly worse subjective health than non-poor adolescents. Relatively poor adolescents also experienced many other social disadvantages, such as parental unemployment and parental ill health. Comparisons between the relatively poor and the non-poor adolescents, using propensity score matching, indicated a negative impact of relative poverty on the subjective health among those adolescents who lived in families with relatively few economic resources. The results suggest that there is a causal component in the association between relative poverty and the symptom burden of disadvantaged adolescents. Relative poverty is only one of many determinants of adolescents’ subjective health, but its role should be acknowledged when policies for promoting adolescent health are designed. PMID:23249858
Kanda, Mitsuro; Oba, Koji; Aoyama, Toru; Kashiwabara, Kosuke; Mayanagi, Shuhei; Maeda, Hiromichi; Honda, Michitaka; Hamada, Chikuma; Sadahiro, Sotaro; Sakamoto, Junichi; Saji, Shigetoyo; Yoshikawa, Takaki
2018-04-01
Although colorectal cancer comprises several histological subtypes, the influences of histological subtypes on disease progression and treatment responses remain controversial. We sought to evaluate the prognostic relevance of mucinous and poorly differentiated histological subtypes of colorectal cancer by the propensity score weighting analysis of prospectively collected data from multi-institute phase III trials. Independent patient data analysis of a pooled database from 3 phase III trials was performed. An integrated database of 3 multicenter prospective clinical trials (the Japanese Foundation for Multidisciplinary Treatment of Cancer 7, 15, and 33) was the source of study data. Surgery alone or postoperative adjuvant chemotherapy was offered in patients with resectable colorectal cancer. To balance essential variables more strictly for the comparison analyses, propensity score weighting was conducted with the use of a multinomial logistic regression model. We evaluated the clinical signatures of mucinous and poorly differentiated subtypes with regard to postoperative survival, recurrence, and chemosensitivity. Of 5489 patients, 136 (2.5%) and 155 (2.8%) were pathologically diagnosed with poorly differentiated and mucinous subtypes. The poorly differentiated subtypes were associated with a poorer prognosis than the "others" group (HR, 1.69; 95% CI, 1.00-2.87; p = 0.051), particularly in the patient subgroup of adjuvant chemotherapy (HR, 2.16). Although the mucinous subtype had a marginal prognostic impact among patients with stage I to III colorectal cancer (HR, 1.33; 95% CI, 0.90-1.96), it was found to be an independent prognostic factor in the subpopulation of patients with stage II disease, being associated with a higher prevalence of peritoneal recurrence. The treatment regimens of postoperative chemotherapy are now somewhat outdated. Both mucinous and poorly differentiated subtypes have distinct clinical characteristics. Patients with the mucinous subtype
Adams, N; Tudehope, D; Gibbons, K S; Flenady, V
2018-01-01
To examine whether disparities in stillbirth, and neonatal and perinatal mortality rates, between public and private hospitals are the result of differences in population characteristics and/or clinical practices. Retrospective cohort study. A metropolitan tertiary centre encompassing public and private hospitals. Women accessed care from either a private obstetrician or from public models of care - predominantly midwife-led care or care shared between midwives, general practitioners, and obstetricians. A total of 131 436 births during 1998-2013: 69 037 public and 62 399 private. Propensity score matching was used to select equal-sized public and private cohorts with similar characteristics. Logistic regression analysis was then used to explore the impact of public-private differences in the use of assisted reproductive technologies, plurality, major congenital anomalies, birth method, and gestational age. Stillbirth, and neonatal and perinatal mortality rates. After controlling for maternal and pregnancy factors, perinatal mortality rates were higher in the public than in the private cohort (adjusted odds ratio, aOR 1.53; 95% confidence interval, 95% CI 1.29-1.80; stillbirth aOR 1.56, 95% CI 1.26-1.94; neonatal death aOR 1.48, 95% CI 1.15-1.89). These disparities reduced by 15.7, 20.5, and 19.6%, respectively, after adjusting for major congenital anomalies, birth method, and gestational age. Perinatal mortality occurred more often among public than private births, and this disparity was not explained by population differences. Differences in clinical practices seem to be partly responsible. The impact of differences in clinical practices on maternal and neonatal morbidity was not examined. Further research is required. Private obstetrician-led care: more obstetric intervention and earlier births reduce perinatal mortality. Background Babies born in Australian public hospitals tend to die more often than those born in private hospitals. Our aim was to determine
Eeren, Hester V; Goossens, Lucas M A; Scholte, Ron H J; Busschbach, Jan J V; van der Rijken, Rachel E A
2018-01-09
Multisystemic Therapy (MST) and Functional Family Therapy (FFT) have overlapping target populations and treatment goals. In this study, these interventions were compared on their effectiveness using a quasi-experimental design. Between October, 2009 and June, 2014, outcome data were collected from 697 adolescents (mean age 15.3 (SD 1.48), 61.9% male) assigned to either MST or FFT (422 MST; 275 FFT). Data were gathered during Routine Outcome Monitoring. The primary outcome was externalizing problem behavior (Child Behavior Checklist and Youth Self Report). Secondary outcomes were the proportion of adolescents living at home, engaged in school or work, and who lacked police contact during treatment. Because of the non-random assignment, a propensity score method was used to control for observed pre-treatment differences. Because the risk-need-responsivity (RNR) model guided treatment assignment, effectiveness was also estimated in youth with and without a court order as an indicator of their risk level. Looking at the whole sample, no difference in effect was found with regard to externalizing problems. For adolescents without a court order, effects on externalizing problems were larger after MST. Because many more adolescents with a court order were assigned to MST compared to FFT, the propensity score method could not balance the treatment groups in this subsample. In conclusion, few differences between MST and FFT were found. In line with the RNR model, higher risk adolescents were assigned to the more intensive treatment, namely MST. In the group with lower risk adolescents, this more intensive treatment was more effective in reducing externalizing problems.
Wang, Xia; Arima, Hisatomi; Yang, Jie; Zhang, Shihong; Wu, Guojun; Woodward, Mark; Muñoz-Venturelli, Paula; Lavados, Pablo M; Stapf, Christian; Robinson, Thompson; Heeley, Emma; Delcourt, Candice; Lindley, Richard I; Parsons, Mark; Chalmers, John; Anderson, Craig S
2015-10-01
Mannitol is often used to reduce cerebral edema in acute intracerebral hemorrhage but without strong supporting evidence of benefit. We aimed to determine the impact of mannitol on outcome among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2). INTERACT2 was an international, open, blinded end point, randomized controlled trial of 2839 patients with spontaneous intracerebral hemorrhage (<6 hours) and elevated systolic blood pressure allocated to intensive (target systolic blood pressure, <140 mm Hg within 1 hour) or guideline-recommended (target systolic blood pressure, <180 mm Hg) blood pressure-lowering treatment. Propensity score and multivariable analyses were performed to investigate the relationship between mannitol treatment (within 7 days) and poor outcome, defined by death or major disability on the modified Rankin Scale score (3-6) at 90 days. There was no significant difference in poor outcome between mannitol (n=1533) and nonmannitol (n=993) groups: propensity score-matched odds ratio of 0.90 (95% confidence interval, 0.75-1.09; P=0.30) and multivariable odds ratio of 0.87 (95% confidence interval, 0.71-1.07; P=0.18). Although a better outcome was suggested in patients with larger (≥15 mL) than those with smaller (<15 mL) baseline hematomas who received mannitol (odds ratio, 0.52 [95% confidence interval, 0.35-0.78] versus odds ratio, 0.91 [95% confidence interval, 0.72-1.15]; P homogeneity<0.03 in propensity score analyses), the association was not consistent in analyses across other cutoff points (≥10 and ≥20 mL) and for differing grades of neurological severity. Mannitol was not associated with excess serious adverse events. Mannitol seems safe but might not improve outcome in patients with acute intracerebral hemorrhage. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00716079. © 2015 American Heart Association, Inc.
ERIC Educational Resources Information Center
Marts, Jennifer Leigh
2016-01-01
Service-learning has roots deep in higher education. Community colleges and service-learning have an organic relationship as they both strive to represent and support their local communities. This study implemented propensity score matching to study the impact of service-learning on student outcomes for community college students. Much of the…
Chang, Xiaofeng; Zhang, Fan; Liu, Tieshi; Wang, Wei; Guo, Hongqian
2017-06-01
To investigate the role of neutrophil-to-lymphocyte ratio as a prognostic indicator in patients with localized clear cell renal cell carcinoma treated with radiofrequency ablation. We retrospectively analyzed data from patients with renal cell carcinoma who underwent radiofrequency ablation from 2006 to 2013. The Kaplan-Meier method was used to generate the survival curves according to different categories of neutrophil-to-lymphocyte ratio. Relationships between preoperative neutrophil-to-lymphocyte ratio or the change of neutrophil-to-lymphocyte ratio and survival were evaluated with multivariable Cox proportional hazards regression analysis. A propensity score matching analysis was carried out to avoid confounding bias. A total of 185 patients were included in present study. When stratified by preoperative neutrophil-to-lymphocyte ratio cutoff value of 2.79, 5-year recurrence-free survival, 5-year disease-free survival, and 5-year overall survival rates of neutrophil-to-lymphocyte ratio <2.79 versus ≥2.79 were 100, 98.5, and 99.2% versus 80.5, 72.6, and 90.6%, respectively (P < 0.001, P < 0.001, P = 0.003). In terms of propensity score matching analysis, 5-year recurrence-free survival, 5-year disease-free survival, and 5-year overall survival rates of neutrophil-to-lymphocyte ratio <2.79 versus ≥2.79 were 100, 97.9, and 100% versus 82.3, 73.4, and 89.4%, respectively (P = 0.003, P = 0.001, P = 0.022). When combining preoperative neutrophil-to-lymphocyte ratio with the change of neutrophil-to-lymphocyte ratio, patients with both preoperative neutrophil-to-lymphocyte ratio ≥2.79 and the change of neutrophil-to-lymphocyte ratio ≥0.40 had the worst disease-free survival. Results of multivariable analysis showed that preoperative neutrophil-to-lymphocyte ratio and the change of neutrophil-to-lymphocyte ratio correlated with cancer relapse remarkably. High preoperative neutrophil-to-lymphocyte ratio and elevated postoperative neutrophil
Umbrello, Michele; Mistraletti, Giovanni; Corbella, Davide; Cigada, Marco; Salini, Silvia; Morabito, Alberto; Iapichino, Gaetano
2012-12-01
Within the evidence-based medicine paradigm, randomized controlled trials represent the "gold standard" to produce reliable evidence. Indeed, planning and implementing randomized controlled trials in critical care medicine presents limitations because of intrinsic and structural problems. As a consequence, observational studies still occur frequently. In these cases, propensity score (PS) (probability of receiving a treatment conditional on observed covariates) is an increasingly used technique to adjust the results. Few studies addressed the specific issue of a PS correction of repeated-measures designs. Three techniques for correcting the analysis of nonrandomized designs (matching, stratification, regression adjustment) are presented in a tutorial form and applied to a real case study: the comparison between intravenous and enteral sedative therapy in the intensive care unit setting. After showing the results before and after the use of PS, we suggest that such a tool allows to partially overcoming the bias associated with the observational nature of the study. It permits to correct the estimates for any observed covariate, while unobserved confounders cannot be controlled for. Propensity score represents a useful additional tool to estimate the effects of treatments in nonrandomized studies. In the case study, an enteral sedation approach was equally effective to an intravenous regime, allowing for a lower level of sedation and spare of resources. Copyright © 2012 Elsevier Inc. All rights reserved.
He, Hua; McDermott, Michael P.
2012-01-01
Sensitivity and specificity are common measures of the accuracy of a diagnostic test. The usual estimators of these quantities are unbiased if data on the diagnostic test result and the true disease status are obtained from all subjects in an appropriately selected sample. In some studies, verification of the true disease status is performed only for a subset of subjects, possibly depending on the result of the diagnostic test and other characteristics of the subjects. Estimators of sensitivity and specificity based on this subset of subjects are typically biased; this is known as verification bias. Methods have been proposed to correct verification bias under the assumption that the missing data on disease status are missing at random (MAR), that is, the probability of missingness depends on the true (missing) disease status only through the test result and observed covariate information. When some of the covariates are continuous, or the number of covariates is relatively large, the existing methods require parametric models for the probability of disease or the probability of verification (given the test result and covariates), and hence are subject to model misspecification. We propose a new method for correcting verification bias based on the propensity score, defined as the predicted probability of verification given the test result and observed covariates. This is estimated separately for those with positive and negative test results. The new method classifies the verified sample into several subsamples that have homogeneous propensity scores and allows correction for verification bias. Simulation studies demonstrate that the new estimators are more robust to model misspecification than existing methods, but still perform well when the models for the probability of disease and probability of verification are correctly specified. PMID:21856650
Sullivan, Amanda L; Field, Samuel
2013-04-01
The purpose of this study was to examine the average treatment effect of preschool special education services on children's kindergarten academic skills. Using data from a nationally representative sample of United States children who participated in the Early Childhood Longitudinal Study-Birth Cohort, we examined the effectiveness of preschool special education services by comparing reading and math outcomes for children who received special education services at preschool-age to a propensity-score-weighted sample of children who did not receive these services. Results indicated that the receipt of these special education services had a statistically significant moderate negative effect on children's kindergarten skills in both reading (d=-0.21) and mathematics (d=-0.29). These findings have implications for the implementation and evaluation of services for young children experiencing developmental delays or disabilities. Copyright © 2012 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.
Kim, Yeon-Jin; Jang, Hye Min; Lee, Youngjo; Lee, Donghwan; Kim, Dai-Jin
2018-04-25
The associations of Internet addiction (IA) and smartphone addiction (SA) with mental health problems have been widely studied. We investigated the effects of IA and SA on depression and anxiety while adjusting for sociodemographic variables. In this study, 4854 participants completed a cross-sectional web-based survey including socio-demographic items, the Korean Scale for Internet Addiction, the Smartphone Addiction Proneness Scale, and the subscales of the Symptom Checklist 90 Items-Revised. The participants were classified into IA, SA, and normal use (NU) groups. To reduce sampling bias, we applied the propensity score matching method based on genetics matching. The IA group showed an increased risk of depression (relative risk 1.207; p < 0.001) and anxiety (relative risk 1.264; p < 0.001) compared to NUs. The SA group also showed an increased risk of depression (relative risk 1.337; p < 0.001) and anxiety (relative risk 1.402; p < 0.001) compared to NCs. These findings show that both, IA and SA, exerted significant effects on depression and anxiety. Moreover, our findings showed that SA has a stronger relationship with depression and anxiety, stronger than IA, and emphasized the need for prevention and management policy of the excessive smartphone use.
Rau, Cheng-Shyuan; Wu, Shao-Chun; Kuo, Pao-Jen; Chen, Yi-Chun; Chien, Peng-Chen; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua
2017-01-01
Background: Polytrauma patients are expected to have a higher risk of mortality than that obtained by the summation of expected mortality owing to their individual injuries. This study was designed to investigate the outcome of patients with polytrauma, which was defined using the new Berlin definition, as cases with an Abbreviated Injury Scale (AIS) ≥ 3 for two or more different body regions and one or more additional variables from five physiologic parameters (hypotension [systolic blood pressure ≤ 90 mmHg], unconsciousness [Glasgow Coma Scale score ≤ 8], acidosis [base excess ≤ −6.0], coagulopathy [partial thromboplastin time ≥ 40 s or international normalized ratio ≥ 1.4], and age [≥70 years]). Methods: We retrieved detailed data on 369 polytrauma patients and 1260 non-polytrauma patients with an overall Injury Severity Score (ISS) ≥ 18 who were hospitalized between 1 January 2009 and 31 December 2015 for the treatment of all traumatic injuries, from the Trauma Registry System at a level I trauma center. Patients with burn injury or incomplete registered data were excluded. Categorical data were compared with two-sided Fisher exact or Pearson chi-square tests. The unpaired Student t-test and the Mann–Whitney U-test was used to analyze normally distributed continuous data and non-normally distributed data, respectively. Propensity-score matched cohort in a 1:1 ratio was allocated using the NCSS software with logistic regression to evaluate the effect of polytrauma on patient outcomes. Results: The polytrauma patients had a significantly higher ISS than non-polytrauma patients (median (interquartile range Q1–Q3), 29 (22–36) vs. 24 (20–25), respectively; p < 0.001). Polytrauma patients had a 1.9-fold higher odds of mortality than non-polytrauma patients (95% CI 1.38–2.49; p < 0.001). Compared to non-polytrauma patients, polytrauma patients had a substantially longer hospital length of stay (LOS). In addition, a higher proportion of
Koo, Kyo Chul; Park, Sang Un; Jang, Ho Sung; Hong, Chang-Hee
2015-11-01
The purpose of this study was to determine the efficacy and safety of tubeless percutaneous nephrolithotomy (PNL) using a non-absorbable hemostatic sealant (Quikclot(®)) as an adjunct compared to nephrostomy tube placement in patients exhibiting significant parenchymal bleeding following PNL. We identified 113 PNL cases performed between May 2011 and October 2014. For patients with insignificant parenchymal bleeding following stone removal, defined as a clear visualization of the surgical field at full irrigation of the nephroscope, tubeless PNL was performed. For patients with significant parenchymal bleeding, we introduced the tubeless Quikclot(®) technique as of September 2013 and have performed it ever since. Formerly, nephrostomy placement PNL was performed. In this study, 40 Quikclot(®) applied PNL cases were matched with an equal number of nephrostomy placement cases by propensity scoring based on body mass index, stone size, and Guy's stone score. The mean postoperative drop in hematocrit was comparative between the Quikclot(®) group and the nephrostomy group on both postoperative days 1 (p = 0.459) and 2 (p = 0.325). Quikclot(®) application was associated with lower VAS scores throughout the postoperative period, lower cumulative analgesic requirement (p = 0.025), and with shorter hospitalization (p = 0.002). Complication rates were comparable with no need for blood transfusions in any patients. Tubeless Quikclot(®) PNL was safe and provided effective hemostasis of significant parenchymal bleeding. By avoiding nephrostomy placement, we were able to reduce postoperative pain, analgesic requirements, and hospitalization. Application of Quikclot(®) may be considered prior to nephrostomy placement in patients with significant parenchymal bleeding.
Koie, Takuya; Mitsuzuka, Koji; Yoneyama, Takahiro; Narita, Shintaro; Kawamura, Sadafumi; Kaiho, Yasuhiro; Tsuchiya, Norihiko; Tochigi, Tatsuo; Habuchi, Tomonori; Arai, Yoichi; Ohyama, Chikara; Yoneyama, Tohru; Tobisawa, Yuki
2015-10-01
The optimal treatment for high-risk prostate cancer (Pca) remains to be established. We previously reported favorable biochemical recurrence-free survival (BRFS) in high-risk Pca patients treated with a neoadjuvant therapy comprising a luteinizing-hormone-releasing hormone (LHRH) agonist plus low dose estramustine phosphate (EMP) (LHRH+EMP) followed by radical prostatectomy (RP). In the present study, we used a retrospective design via propensity score matching to elucidate the clinical benefit of neoadjuvant LHRH+EMP for high-risk Pca. The Michinoku Urological Cancer Study Group database contained data for 1,268 consecutive Pca patients treated with RP alone at 4 institutions between April 2000 and March 2011 (RP alone group). In the RP alone group, we identified 386 high-risk Pca patients. The neoadjuvant LHRH+EMP group included 274 patients with high-risk Pca treated between September 2005 and November 2013 at Hirosaki University. Neoadjuvant LHRH+EMP therapy included LHRH and EMP administration at a dose of 280 mg/day for 6 months before RP. The outcome measures were overall survival (OS) and BRFS. The propensity score-matched analysis indicated 210 matched pairs from both groups. The 5-year BRFS rates were 90.4 and 65.8 % for the neoadjuvant LHRH+EMP and RP alone groups, respectively (P < 0.0001). The 5-year OS rates were 100 and 96.1 % for the neoadjuvant LHRH+EMP and RP alone groups, respectively (P = 0.110). Although the present study was not randomized, neoadjuvant LHRH+EMP therapy followed by RP appeared to reduce the risk of biochemical recurrence. A prospective randomized study is warranted to determine the clinical implications of the neoadjuvant therapy described here.
Yan, Shi; Wang, Xing; Wang, Yaqi; Lv, Chao; Wang, Yuzhao; Wang, Jia; Yang, Yue; Wu, Nan
2017-12-01
Postoperative pleural drainage markedly influences the length of hospital stay and the financial costs of medical care. The safety of chest tube clamping before removal has been documented. This study aims to determine if intermittent chest tube clamping shortens the duration of chest tube drainage and hospital stay after lung cancer surgery. We retrospectively analyzed 285 consecutive patients with operable lung cancer treated using lobectomy and systematic mediastinal lymphadenectomy. The chest tube management protocol in our institution was changed in January 2014, and thus, 222 patients (clamping group) were managed with intermittent chest tube clamping, while 63 patients (control group) were managed with a traditional protocol. Propensity score matching at a 1:1 ratio was applied to balance variables potentially affecting the duration of chest tube drainage. Analyses were performed to compare drainage duration and postoperative hospital stay between the two groups in the matched cohort. Multivariate logistic regression analyses were performed to predict the factors associated with chest tube drainage duration. The rates of thoracocentesis after chest tube removal were similar between the clamping and control groups in the whole cohort (0.5% vs. 1.6%, P=0.386). The rates of pyrexia were also comparable in the two groups (2.3% vs. 3.2%, P=0.685). After propensity score matching, 61 cases remained in each group. Both chest tube drainage duration (3.9 vs. 4.8 days, P=0.001) and postoperative stay (5.7 vs. 6.4 days, P=0.025) were significantly shorter in the clamping group than in the control group. Factors significantly associated with shorter chest tube drainage duration were female sex, chest tube clamping, left lobectomy, and video-assisted thoracoscopic surgery (VATS) (P<0.05). Intermittent postoperative chest tube clamping may decrease the duration of chest tube drainage and postoperative hospital stay while maintaining patient safety.
Kinouchi, Kaori; Ohashi, Kazutomo
2018-01-01
The purpose of this study was to evaluate the efficacy of a smartphone-based reminder system in promoting pelvic floor muscle training (PFMT) to help postpartum women manage urinary incontinence (UI). Forty-nine and 212 postpartum women in the intervention and control groups, respectively, received PFMT guidance using a leaflet and verbal instruction as the standard care at an obstetrics clinic in Japan. Women in the intervention group also received PFMT support using the smartphone-based reminder system between January and August 2014. For analysis, they were compared with historical controls between February 2011 and January 2012, who did not receive such support and were chosen by propensity score matching. The outcomes examined were PFMT adherence and UI prevalence. The former consisted of implementation rate (i.e., the percentage of women who reported performing PFMT during the intervention period), training intensity (i.e., the number of pelvic floor muscle contractions (PFMCs) per day), and training frequency (i.e., the number of days PFMT was performed per week); the latter consisted of self-reported UI prevalence at baseline and at the end of the eight-week intervention period. Propensity score matching resulted in 58 postpartum women ( n = 29 per group). The intervention group exhibited better PFMT adherence than the control group, in terms of PFMT implementation rate (69 vs. 31%, p = 0.008), median training intensity (15 vs. 1 PFMC reps/day, p = 0.006), and training frequency (7 vs. 3 days/week, p < 0.001). UI prevalence was not different between the groups at baseline, but was significantly reduced in the intervention group at eight weeks (0 vs. 24%, p = 0.004). Our smartphone-based reminder system appears promising in enhancing PFMT adherence and managing postpartum UI in postpartum women. By enhancing PFMT adherence and improving women's ability to manage the condition, the reminder system could improve the health-related quality of
Kim, Yong Gil; Graham, David Y; Jang, Byung Ik
2012-01-01
Clostridium difficile has been increasingly diagnosed in hospitalized patients. An association between proton pump inhibitors (PPIs) use and Clostridium difficile-associated disease (CDAD) and between recurrent CDAD has been suggested. The aim of this study is to investigate whether PPI use is associated with the development of recurrent CDAD. This was a retrospective case-control study of patients with CDAD at Yeungnam University Medical Center, seen from January 2004 to December 2008. C. difficile infection was diagnosed by the presence of C. difficile toxin in the stool. Those with recurrent disease were matched with nonrecurrent controls using multivariate matched sampling methods that incorporated the propensity score. Recurrent CDAD developed in 28 (14.1%) of the 198 patients with diarrhea and positive C. difficile stool toxin assays. Multivariate analysis of the total population of recurrent versus nonrecurrent CDAD revealed that additional use of non-C. difficile antimicrobial therapy (concomitant with the treatment or after or both), poor response to therapy with metronidazole or vancomycin, and recent gastrointestinal surgery were risk factors for recurrent CDAD. We were able to match 21 recurrent CDAD subjects with 21 without recurrent CDAD. Among the matched patients only PPI use was associated with recurrent CDAD (ie, 47.6% vs. 4.8%, P=0.004 for recurrent vs. nonrecurrent CDAD, respectively). Among the matched patient groups, only PPI therapy was associated with recurrent CDAD. Prospective studies are needed to clarify whether avoidance of PPIs or specific cotherapies will reduce the incidence of recurrent C. difficile-associated diarrhea.
Teacher-child relationships and academic achievement: a multilevel propensity score model approach.
McCormick, Meghan P; O'Connor, Erin E; Cappella, Elise; McClowry, Sandee G
2013-10-01
A robust body of research finds positive cross-sectional and longitudinal associations between teacher-child relationships and children's academic achievement in elementary school. Estimating the causal effect of teacher-child relationships on children's academic achievement, however, is challenged by selection bias at the individual and school level. To address these issues, we used two multilevel propensity score matching approaches to estimate the effect of high-quality teacher-child relationships in kindergarten on math and reading achievement during children's transition to first grade. Multi-informant data were collected on 324 low-income, Black and Hispanic students, and 112 kindergarten and first-grade teachers. Results revealed significant effects of high-quality teacher-child relationships in kindergarten on math achievement in first grade. No significant effects of teacher-child relationships were detected for reading achievement. Implications for intervention development and public policy are discussed. Copyright © 2013 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.
Park, Jun Chul; Kim, Yeong Jin; Kim, Eun Hye; Lee, Jinae; Yang, Hyun Su; Kim, Eun Hwa; Hahn, Kyu Yeon; Shin, Sung Kwan; Lee, Sang Kil; Lee, Yong Chan
2018-02-07
Recently, the application of hemostatic powder to the bleeding site has been used to treat active upper gastrointestinal bleeding (UGIB). We aimed to assess the effectiveness of the polysaccharide hemostatic powder (PHP) in patients with non-variceal UGIB. We reviewed prospectively collected 40 patients with UGIB treated with PHP therapy between April 2016 and January 2017 (PHP group) and 303 patients with UGIB treated with conventional therapy between April 2012 and October 2014 (conventional therapy group). We compared the rate of successful hemostasis and the rebleeding between the two groups after as well as before propensity score matching using the Glasgow-Blatchford score and Forrest classification. Thirty patients treated with the PHP and 60 patients treated with conventional therapy were included in the matched groups. Baseline patient characteristics including comorbidities, vital signs, and bleeding scores were similar in the matched groups. The rate of immediate hemostasis and 7-day and 30-day rebleeding were also similar in the two groups before and after matching. In the subgroup analysis, no significant differences in immediate hemostasis or rebleeding rate were noted between PHP in monotherapy and PHP combined with a conventional hemostatic method. At 30 days after the therapy, there were no significant PHP-related complications or mortality. Given its safety, the PHP proved feasible for endoscopic treatment of UGIB, having similar effectiveness as that of conventional therapy. The PHP may become a promising hemostatic method for non-variceal UGIB. © 2018 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.
Balancing Score Adjusted Targeted Minimum Loss-based Estimation
Lendle, Samuel David; Fireman, Bruce; van der Laan, Mark J.
2015-01-01
Adjusting for a balancing score is sufficient for bias reduction when estimating causal effects including the average treatment effect and effect among the treated. Estimators that adjust for the propensity score in a nonparametric way, such as matching on an estimate of the propensity score, can be consistent when the estimated propensity score is not consistent for the true propensity score but converges to some other balancing score. We call this property the balancing score property, and discuss a class of estimators that have this property. We introduce a targeted minimum loss-based estimator (TMLE) for a treatment-specific mean with the balancing score property that is additionally locally efficient and doubly robust. We investigate the new estimator’s performance relative to other estimators, including another TMLE, a propensity score matching estimator, an inverse probability of treatment weighted estimator, and a regression-based estimator in simulation studies. PMID:26561539
ERIC Educational Resources Information Center
Arikan, Serkan; van de Vijver, Fons J. R.; Yagmur, Kutlay
2018-01-01
We examined Differential Item Functioning (DIF) and the size of cross-cultural performance differences in the Programme for International Student Assessment (PISA) 2012 mathematics data before and after application of propensity score matching. The mathematics performance of Indonesian, Turkish, Australian, and Dutch students on released items was…
Lu, Chien-Hsing; Chang, Yen-Hou; Lee, Wai-Hou; Chang, Yi; Peng, Chia-Wen; Chuang, Chi-Mu
2016-01-01
The superiority of frontline intraperitoneal (IP) over intravenous (IV) chemotherapy is well established in the treatment of epithelial ovarian cancer. However, the role of IP chemotherapy in the second-line setting has rarely been investigated. Consecutive patients diagnosed with recurrent epithelial, tubal and peritoneal cancers between January 2000 and December 2012 were recruited using a propensity score-matching technique to adjust relevant risk factors. In total, 310 patients were included in the final analysis (94 for platinum-refractory/resistant disease and 216 for platinum-sensitive disease). IP chemotherapy demonstrated significantly longer median progression-free survival than IV chemotherapy (4.9 vs. 2.4 months, p < 0.001, for platinum-refractory/resistant disease, and 9.8 vs. 6.9 months, p < 0.001, for platinum-sensitive disease). Second-line IP chemotherapy confers longer progression-free survival than IV chemotherapy. Large-scale clinical trials should be conducted to validate the true efficacy. © 2016 S. Karger AG, Basel.
Ruzek, Erik; Burchinal, Margaret; Farkas, George; Duncan, Greg J
2014-01-01
Over half of the toddlers in the U.S. experience routine nonparental care, but much less is known about early care than about preschool care. This study analyzed 2-year-old child care and child outcome data from the nationally representative ECLS-B sample of children born in 2001. At two-years of age, 51% of children experienced exclusive parental care, 18% relative care, 15% family child care, and 16% center care. More children in nonparental care were in medium quality care (61%) than in high quality (26%) or low quality (13%) care. Low-income children were more likely than non-low income children to be cared for by their parents and, when in care, were more often in lower quality care. The impact of toddler care quality on cognitive skills was estimated using propensity score adjustments to account for potential selection confounds due to family and child characteristics. Children's cognitive scores were higher in high or medium quality care than in low quality care, but no evidence emerged suggesting that poverty moderated the quality effects. Nevertheless, this suggests that increasing the proportion of low-income children in high quality care could reduce the achievement gap because low-income children are very unlikely to experience high quality care.
Ruzek, Erik; Burchinal, Margaret; Farkas, George; Duncan, Greg J.
2013-01-01
Over half of the toddlers in the U.S. experience routine nonparental care, but much less is known about early care than about preschool care. This study analyzed 2-year-old child care and child outcome data from the nationally representative ECLS-B sample of children born in 2001. At two-years of age, 51% of children experienced exclusive parental care, 18% relative care, 15% family child care, and 16% center care. More children in nonparental care were in medium quality care (61%) than in high quality (26%) or low quality (13%) care. Low-income children were more likely than non-low income children to be cared for by their parents and, when in care, were more often in lower quality care. The impact of toddler care quality on cognitive skills was estimated using propensity score adjustments to account for potential selection confounds due to family and child characteristics. Children’s cognitive scores were higher in high or medium quality care than in low quality care, but no evidence emerged suggesting that poverty moderated the quality effects. Nevertheless, this suggests that increasing the proportion of low-income children in high quality care could reduce the achievement gap because low-income children are very unlikely to experience high quality care. PMID:24347815
Suissa, Samy; Moodie, Erica E M; Dell'Aniello, Sophie
2017-04-01
Studies of the real-world comparative effectiveness of drugs conducted using computerized healthcare databases typically involve an incident new-user cohort design for head-to-head comparisons between two medications, using exclusively treatment-naïve patients. However, the desired contrast often involves one new drug compared with an older drug, of which many users of the new drug may have switched from, seriously restricting the scope of incident new-user studies. We introduce prevalent new-user cohort designs for head-to-head comparative drug effect studies, where incident new users are scarce. We define time-based and prescription-based exposure sets to compute time-conditional propensity scores of initiating the newer drug and to identify matched subjects receiving the comparator drug. We illustrate this approach using data from the UK's Clinical Practice Research Datalink to evaluate whether the newer glucagon-like peptide-1 receptor agonists (GLP-1 analogs) used to treat type 2 diabetes increase the risk of heart failure, in comparison with the older similarly indicated sulfonylureas. Of the 170 031 users of antidiabetic agents from 2000 onwards, 79 682 used sulfonylureas (first use 2000), while 6196 used GLP-1 analogs (first use 2007), 75% of which had previously used a sulfonylurea. After matching each GLP-1 analog user to a sulfonylurea user on the time-conditional propensity scores from prescription-based exposure sets, the hazard ratio of heart failure with GLP-1 use was 0.73 (95%CI: 0.57-0.93). The proposed prevalent new-user cohort design for comparative drug effects studies allows the use of all or most patients exposed to the newer drug, thus permitting a more comprehensive assessment of a new drug's safety. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Tashiro, Jun; Perez, Eduardo A; Sola, Juan E
2016-03-01
To evaluate outcomes after surgical ligation (SL) of patent ductus arteriosus (PDA) in premature, extremely low birth weight (ELBW) infants. Optimal management of PDA in this specialized population remains undefined. Currently, surgical therapy is largely reserved for infants failing medical management. To date, a large-scale, risk-matched population-based study has not been performed to evaluate differences in mortality and resource utilization. Data on identified premature (<37 weeks) and ELBW (<1000 g) infants with PDA (International Classification of Diseases, 9th revision, Clinical Modification, 747.0) and respiratory distress (769) were obtained from Kids' Inpatient Database (2003-2009). Overall, 12,470 cases were identified, with 3008 undergoing SL. Propensity score-matched analysis of 1620 SL versus 1584 non-SL found reduced mortality (15% vs 26%) and more routine disposition (48% vs 41%) for SL (P < 0.001). SL had longer length of stay and higher total cost (P < 0.001). On multivariate analysis, SL mortality predictors were necrotizing enterocolitis (NEC; surgical odds ratio, 5.95; medical odds ratio, 4.42) and sepsis (3.43) (P < 0.006). Length of stay increased with bronchopulmonary dysplasia (BPD; 1.77), whereas total cost increased with surgical NEC (1.82) and sepsis (1.26) (P < 0.04). Non-SL mortality predictors were NEC (surgical, 76.3; medical, 6.17), sepsis (2.66), and intraventricular hemorrhage (1.97) (P < 0.005). Length of stay increased with BPD (2.92) and NEC (surgical, 2.04; medical, 1.28) (P < 0.03). Total cost increased with surgical NEC (2.06), medical NEC (1.57), sepsis (1.43), and BPD (1.30) (P < 0.001). Propensity score-matched analysis demonstrates reduced mortality in premature/ELBW infants with SL for PDA. NEC and sepsis are predictors of mortality and resource utilization.
Hamady, Zaed Z R; Lodge, J Peter A; Welsh, Fenella K; Toogood, Giles J; White, Alan; John, Timothy; Rees, Myrddin
2014-03-01
To investigate the influence of clear surgical resection margin width on disease recurrence rate after intentionally curative resection of colorectal liver metastases. There is consensus that a histological positive resection margin is a predictor of disease recurrence after resection of colorectal liver metastases. The dispute, however, over the width of cancer-free resection margin required is ongoing. Analysis of observational prospectively collected data for 2715 patients who underwent primary resection of colorectal liver metastases from 2 major hepatobiliary units in the United Kingdom. Histological cancer-free resection margin was classified as positive (if cancer cells present at less than 1 mm from the resection margin) or negative (if the distance between the cancer and the margin is 1 mm or more). The negative margin was further classified according to the distance from the tumor in millimeters. Predictors of disease-free survival were analyzed in univariate and multivariate analyses. A case-match analysis by a propensity score method was undertaken to reduce bias. A 1-mm cancer-free resection margin was sufficient to achieve 33% 5-year overall disease-free survival. Extra margin width did not add disease-free survival advantage (P > 0.05). After the propensity case-match analysis, there is no statistical difference in disease-free survival between patients with negative narrow and wider margin clearance [hazard ratio (HR) 1.0; 95% (confidence interval) CI: 0.9-1.2; P = 0.579 at 5-mm cutoff and HR 1.1; 95% CI: 0.96-1.3; P = 0.149 at 10-mm cutoff]. Patients with extrahepatic disease and positive lymph node primary tumor did not have disease-free survival advantage despite surgical margin clearance (9 months for <1-mm vs 12 months for ≥1-mm margin clearance; P = 0.062). One-mm cancer-free resection margin achieved in patients with colorectal liver metastases should now be considered the standard of care.
Mishra-Kalyani, Pallavi S.; Johnson, Brent A.; Glass, Jonathan D.; Long, Qi
2016-01-01
Clinical disease registries offer a rich collection of valuable patient information but also pose challenges that require special care and attention in statistical analyses. The goal of this paper is to propose a statistical framework that allows for estimating the effect of surgical insertion of a percutaneous endogastrostomy (PEG) tube for patients living with amyotrophic lateral sclerosis (ALS) using data from a clinical registry. Although all ALS patients are informed about PEG, only some patients agree to the procedure which, leads to the potential for selection bias. Assessing the effect of PEG is further complicated by the aggressively fatal disease, such that time to death competes directly with both the opportunity to receive PEG and clinical outcome measurements. Our proposed methodology handles the “censoring by death” phenomenon through principal stratification and selection bias for PEG treatment through generalized propensity scores. We develop a fully Bayesian modeling approach to estimate the survivor average causal effect (SACE) of PEG on BMI, a surrogate outcome measure of nutrition and quality of life. The use of propensity score methods within the principal stratification framework demonstrates a significant and positive effect of PEG treatment, particularly when time of treatment is included in the treatment definition. PMID:27640365
NASA Astrophysics Data System (ADS)
Mishra-Kalyani, Pallavi S.; Johnson, Brent A.; Glass, Jonathan D.; Long, Qi
2016-09-01
Clinical disease registries offer a rich collection of valuable patient information but also pose challenges that require special care and attention in statistical analyses. The goal of this paper is to propose a statistical framework that allows for estimating the effect of surgical insertion of a percutaneous endogastrostomy (PEG) tube for patients living with amyotrophic lateral sclerosis (ALS) using data from a clinical registry. Although all ALS patients are informed about PEG, only some patients agree to the procedure which, leads to the potential for selection bias. Assessing the effect of PEG is further complicated by the aggressively fatal disease, such that time to death competes directly with both the opportunity to receive PEG and clinical outcome measurements. Our proposed methodology handles the “censoring by death” phenomenon through principal stratification and selection bias for PEG treatment through generalized propensity scores. We develop a fully Bayesian modeling approach to estimate the survivor average causal effect (SACE) of PEG on BMI, a surrogate outcome measure of nutrition and quality of life. The use of propensity score methods within the principal stratification framework demonstrates a significant and positive effect of PEG treatment, particularly when time of treatment is included in the treatment definition.
Leyrat, Clémence; Caille, Agnès; Foucher, Yohann; Giraudeau, Bruno
2016-01-22
Despite randomization, baseline imbalance and confounding bias may occur in cluster randomized trials (CRTs). Covariate imbalance may jeopardize the validity of statistical inferences if they occur on prognostic factors. Thus, the diagnosis of a such imbalance is essential to adjust statistical analysis if required. We developed a tool based on the c-statistic of the propensity score (PS) model to detect global baseline covariate imbalance in CRTs and assess the risk of confounding bias. We performed a simulation study to assess the performance of the proposed tool and applied this method to analyze the data from 2 published CRTs. The proposed method had good performance for large sample sizes (n =500 per arm) and when the number of unbalanced covariates was not too small as compared with the total number of baseline covariates (≥40% of unbalanced covariates). We also provide a strategy for pre selection of the covariates needed to be included in the PS model to enhance imbalance detection. The proposed tool could be useful in deciding whether covariate adjustment is required before performing statistical analyses of CRTs.
Wood, Jonathan S; Donnell, Eric T; Porter, Richard J
2015-02-01
A variety of different study designs and analysis methods have been used to evaluate the performance of traffic safety countermeasures. The most common study designs and methods include observational before-after studies using the empirical Bayes method and cross-sectional studies using regression models. The propensity scores-potential outcomes framework has recently been proposed as an alternative traffic safety countermeasure evaluation method to address the challenges associated with selection biases that can be part of cross-sectional studies. Crash modification factors derived from the application of all three methods have not yet been compared. This paper compares the results of retrospective, observational evaluations of a traffic safety countermeasure using both before-after and cross-sectional study designs. The paper describes the strengths and limitations of each method, focusing primarily on how each addresses site selection bias, which is a common issue in observational safety studies. The Safety Edge paving technique, which seeks to mitigate crashes related to roadway departure events, is the countermeasure used in the present study to compare the alternative evaluation methods. The results indicated that all three methods yielded results that were consistent with each other and with previous research. The empirical Bayes results had the smallest standard errors. It is concluded that the propensity scores with potential outcomes framework is a viable alternative analysis method to the empirical Bayes before-after study. It should be considered whenever a before-after study is not possible or practical. Copyright © 2014 Elsevier Ltd. All rights reserved.
Cole, Tyler; Veeravagu, Anand; Zhang, Michael; Azad, Tej D; Desai, Atman; Ratliff, John K
2015-07-01
Retrospective 2:1 propensity score-matched analysis on a national longitudinal database between 2006 and 2010. To compare rates of adverse events, revisions procedure rates, and payment differences in anterior cervical fusion procedures compared with posterior laminectomy and fusion procedures with at least 3 levels of instrumentation. The comparative benefits of anterior versus posterior approach to multilevel degenerative cervical disease remain controversial. Recent systematic reviews have reached conflicting conclusions. We demonstrate the comparative economic and clinical outcomes of anterior and posterior approaches for multilevel cervical degenerative disk disease. We identified 13,662 patients in a national billing claims database who underwent anterior or posterior cervical fusion procedures with 3 or more levels of instrumentation. Cohorts were balanced using 2:1 propensity score matching and outcomes were compared using bivariate analysis. With the exception of dysphagia (6.4% in anterior and 1.4% in posterior), overall 30-day complication rates were lower in the anterior approach group. The rate of any complication excluding dysphagia with anterior approaches was 12.3%, significantly lower (P < 0.0001) than that of posterior approaches, 17.8%. Anterior approaches resulted in lower hospital ($18,346 vs. $23,638) and total payments ($28,963 vs. $33,526). Patients receiving an anterior surgical approach demonstrated significantly lower rate of 30-day readmission (5.1% vs. 9.9%, P < 0.0001), were less likely to require revision surgery (12.8% vs. 18.1%, P < 0.0001), and had a shorter length of stay by 1.5 nights (P < 0.0001). Anterior approaches in the surgical management of multilevel degenerative cervical disease provide clinical advantages over posterior approaches, including lower overall complication rates, revision procedure rates, and decreased length of stay. Anterior approach procedures are also associated with decreased overall payments. These
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lin, Steven H., E-mail: SHLin@mdanderson.org; Wang Lu; Myles, Bevan
2012-12-01
Purpose: Although 3-dimensional conformal radiotherapy (3D-CRT) is the worldwide standard for the treatment of esophageal cancer, intensity modulated radiotherapy (IMRT) improves dose conformality and reduces the radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared with 3D-CRT. Methods and Materials: An analysis was performed of 676 nonrandomized patients (3D-CRT, n=413; IMRT, n=263) with stage Ib-IVa (American Joint Committee on Cancer 2002) esophageal cancers treated with chemoradiotherapy at a single institution from 1998-2008. An inverse probability of treatment weighting and inclusion of propensity score (treatment probability) as amore » covariate were used to compare overall survival time, interval to local failure, and interval to distant metastasis, while accounting for the effects of other clinically relevant covariates. The propensity scores were estimated using logistic regression analysis. Results: A fitted multivariate inverse probability weighted-adjusted Cox model showed that the overall survival time was significantly associated with several well-known prognostic factors, along with the treatment modality (IMRT vs 3D-CRT, hazard ratio 0.72, P<.001). Compared with IMRT, 3D-CRT patients had a significantly greater risk of dying (72.6% vs 52.9%, inverse probability of treatment weighting, log-rank test, P<.0001) and of locoregional recurrence (P=.0038). No difference was seen in cancer-specific mortality (Gray's test, P=.86) or distant metastasis (P=.99) between the 2 groups. An increased cumulative incidence of cardiac death was seen in the 3D-CRT group (P=.049), but most deaths were undocumented (5-year estimate, 11.7% in 3D-CRT vs 5.4% in IMRT group, Gray's test, P=.0029). Conclusions: Overall survival, locoregional control, and noncancer-related death were significantly better after IMRT than after 3D-CRT. Although these results need
Coyte, P C; Young, W; Croxford, R
2000-11-01
We estimated the impact of alternative discharge strategies, following joint replacement (JR) surgery, on acute care readmission rates and the total cost of a continuum of care. Following surgery, patients were discharged to one of four destinations. Propensity scores were used to adjust costs and outcomes for potential bias in the assignment of discharge destinations. We demonstrated that the use of rehabilitation hospitals may lower readmission rates, but at a prohibitive incremental cost of each saved readmission, that patients discharged with home care had longer acute care stays than other patients, that the provision of home care services increased health system costs, and that acute care readmission rates were greatest among patients discharged with home care. Our study should be seen as one important stepping stone towards a full economic evaluation of the continuum of care for patients.
Collins, Rebecca L.; Martino, Steven C.; Elliott, Marc N.; Miu, Angela
2013-01-01
Adolescent sexual health is a substantial problem in the U.S., and two recent studies have linked adolescent sexual behavior and/or outcomes to youths' exposure to sex in the media. Both studies had longitudinal survey designs and used covariate-adjusted regression analysis. Steinberg and Monahan (2010) reanalyzed data from one of these studies (Brown et al., 2006) using a propensity-score approach, arguing that this method better addresses the possibility of unobserved confounders. Based on their reanalysis, which found no relationship between media exposure and sexual behavior, they concluded that “Adolescents' Exposure to Sexy Media Does Not Hasten the Initiation of Sexual Intercourse.” We subject data from the second study (Collins et al., 2004; Chandra et al., 2008) to reanalysis using a propensity-score approach. We find only modest reductions in two of the three previously documented associations, and no reduction in the third. Based on these findings, we conclude that there is an association between exposure to sex in the media and adolescent sexual outcomes. While the evidence does not prove causality, it is sufficient to advise caution among parents, develop interventions for youth, and work with media producers and distributors to reduce youth exposure to sexual content. PMID:24839301
Shiraishi, Nariaki; Suzuki, Yusuke; Matsumoto, Daisuke; Jeong, Seungwon; Sugiyama, Motoya; Kondo, Katsunori
2017-03-01
To investigate whether self-exercise programs for patients after stroke contribute to improved activities of daily living (ADL) at hospital discharge. Retrospective, observational, propensity score (PS)-matched case-control study. General hospitals. Participants included patients after stroke (N=1560) hospitalized between January 3, 2006, and December 26, 2012, satisfying the following criteria: (1) data on age, sex, duration from stroke to hospital admission, length of stay, FIM score, modified Rankin Scale (mRS) score, Glasgow Coma Scale score, Japan Stroke Scale score, and self-exercise program participation were available; and (2) admitted within 7 days after stroke onset, length of stay was between 7 and 60 days, prestroke mRS score was ≤2, and not discharged because of FIM or mRS exacerbation. A total of 780 PS-matched pairs were selected for each of the self-exercise program and no-self-exercise program groups. Self-exercise program participation. At discharge, FIM motor score, FIM cognitive score, FIM motor score gain (discharge value - admission value), FIM motor score gain rate (gain/length of stay), a binary variable divided by the median FIM motor score gain rate (high efficiency or no-high efficiency), and mRS score. Patients were classified into a self-exercise program (n=780) or a no-self-exercise program (n=780) group. After matching, there were no significant between-group differences, except motor system variables. The receiver operating characteristic curve for PS had an area under the curve value of .71 with a 95% confidence interval of .68 to .73, and the model was believed to have a relatively favorable fit. A logistic regression analysis of PS-matched pairs suggested that the self-exercise program was effective, with an overall odds ratio for ADL (high efficiency or no-high efficiency) of 2.2 (95% confidence ratio, 1.75-2.70). SEPs may contribute to improving ADL. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by
Perreas, Konstantinos; Samanidis, George; Thanopoulos, Apostolis; Georgiopoulos, Georgios; Antoniou, Theofani; Khoury, Mazen; Michalis, Alkiviadis; Bairaktaris, Andreas
2016-01-01
Over the years, numerous options have been proposed for surgical management of ascending aorta and aortic arch pathology in an attempt to minimize postoperative morbidity and probability of death. We present a propensity score-matching analysis of 259 patients from a single unit who were operated on under deep hypothermic arrest with retrograde cerebral perfusion (DHCA/RCP) or moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion (via common carotid artery) (MHCA/ACP). Between 2006 and 2014 a total of 259 consecutive patients underwent ascending aorta and hemiarch correction under HCA. DHCA/RCP and MHCA/ACP were performed on 207 and 52 patients, respectively. Baseline patient characteristics accounted for in the propensity matching were age, sex, acute aortic dissection, emergency operation, re-operation, preoperative hemodynamic instability, preoperative kidney injury, and CA time. After propensity scoring 40 pairs (80 patients) were successfully matched (p = 0.732). Outcomes were defined as the incidence of postoperative neurologic complications, 30-day mortality, and all-cause midterm mortality. Surgical procedure that involved the MHCA/ACP technique was associated with 76.5% decreased risk (risk ratio, 0.235; 95% CI, 0.079 to 0.699) of postoperative neurologic complications (p = 0.009). In addition to MHCA/ACP in surgical procedure for acute aortic dissection a relevant trend was established for 30-day mortality (risk ratio, 0.333; 95% CI, 0.09 to 1.23). For midterm all-cause mortality, MHCA/ACP modestly decreased the number of deaths (p = 0.0456) in comparison with the DHCA/RCP technique. MHCA/ACP in aortic arch surgical procedure is associated with a decreased risk of all types of neurologic complications and a trend toward decreased 30-day and midterm mortality in comparison with DHCA/RCP. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
Vinsard, Daniela Guerrero; Kandel, Pujan; Mejia Perez, Lady Katherine; Bingham, Russell L.; Lennon, Ryan J.; Woodward, Timothy A.; Gomez, Victoria; Raimondo, Massimo; Bouras, Ernest P.; Wallace, Michael B.
2018-01-01
Background and study aims Risk factors for colorectal adenoma recurrence after endoscopic mucosal resection (EMR) have been well documented. We assessed the efficacy of the newer 190 colonoscope versus the standard 180 colonoscope for complete resection of lateral spreading lesions. Patients and methods A single-center, retrospective study of patients who underwent EMR with Olympus 180 or 190 colonoscopes from January 1, 2010 to September 30, 2016. We included patients with lesions ≥ 20 mm and surveillance colonoscopy (SC1) after index EMR. A propensity score approach with inverse probability weighting was used to control for potential confounders. A secondary aim was to identify risk factors for recurrence and assess the applicability of the Sydney EMR recurrence tool (SERT) by grading each lesion of our cohort and analyzing associations with recurrence. Results Two hundred ninety-one lesions met inclusion criteria for the study. Odds ratio (OR) for recurrence with the 190 colonoscope was 1.06 ( P = .85). Adenoma size ( P = .02) and use of argon plasma coagulation (APC; P < .001) were risk factors for recurrence. Lesions with SERT scores > 0 had a higher recurrence risk during follow-up (32 % vs 21 %; OR 1.71; P = .05). Lesions with SERT scores = 0 reached a plateau for recurrence at 12 and 18 months in Kaplan-Meier curves. Conclusions The use of 190 colonoscopes did not measurably affect adenoma recurrence at SC1. Recurrence was associated with adenoma size, complementary APC for resection, and SERT scores > 0. Lesions with SERT scores = 0 that remain negative for recurrence at 18 months may return to routine surveillance. PMID:29423433
Takagi, Toshio; Kondo, Tsunenori; Tachibana, Hidekazu; Iizuka, Junpei; Omae, Kenji; Kobayashi, Hirohito; Yoshida, Kazuhiko; Tanabe, Kazunari
2017-07-01
To compare surgical outcomes between robot-assisted laparoscopic partial nephrectomy and open partial nephrectomy in patients with chronic kidney disease. Of 550 patients who underwent partial nephrectomy between 2012 and 2015, 163 patients with T1-2 renal tumors who had an estimated glomerular filtration rate between 30 and 60 mL/min/1.73 m 2 , and underwent robot-assisted laparoscopic partial nephrectomy or open partial nephrectomy were retrospectively analyzed. To minimize selection bias between the two surgical methods, patient variables were adjusted by 1:1 propensity score matching. The present study included 75 patients undergoing robot-assisted laparoscopic partial nephrectomy and 88 undergoing open partial nephrectomy. After propensity score matching, 40 patients were included in each operative group. The mean preoperative estimated glomerular filtration rate was 49 mL/min/1.73 m 2 . The mean ischemia time was 21 min in robot-assisted laparoscopic partial nephrectomy (warm ischemia) and 35 min in open partial nephrectomy (cold ischemia). Preservation of the estimated glomerular filtration rate 3-6 months postoperatively was not significantly different between robot-assisted laparoscopic partial nephrectomy and open partial nephrectomy (92% vs 91%, P = 0.9348). Estimated blood loss was significantly lower in the robot-assisted laparoscopic partial nephrectomy group than in the open partial nephrectomy group (104 vs 185 mL, P = 0.0025). The postoperative length of hospital stay was shorter in the robot-assisted laparoscopic partial nephrectomy group than in the open partial nephrectomy group (P < 0.0001). The prevalence of Clavien-Dindo grade 3 complications and a negative surgical margin status were not significantly different between the two groups. In our experience, robot-assisted laparoscopic partial nephrectomy and open partial nephrectomy provide similar outcomes in terms of functional preservation and perioperative complications among patients with
Monlezun, Dominique J.; Leong, Benjamin; Joo, Esther; Birkhead, Andrew G.; Sarris, Leah; Harlan, Timothy S.
2015-01-01
Background. Physicians are inadequately equipped to respond to the global obesity and nutrition-associated chronic disease epidemics. We investigated superiority of simulation-based medical education with deliberate practice (SBME-DP) hands-on cooking and nutrition elective in a medical school-based teaching kitchen versus traditional clinical education for medical students. Materials and Methods. A 59-question panel survey was distributed to an entire medical school twice annually from September 2012 to May 2014. Student diet and attitudes and competencies (DACs) counseling patients on nutrition were compared using conditional multivariate logistic regression, propensity score-weighted, and longitudinal panel analyses. Inverse-variance weighted meta-analysis (IVWM) was used for planned subgroup analysis by year and treatment estimates across the three methods. Results. Of the available 954 students, 65.72% (n = 627) unique students were followed to produce 963 responses. 11.32% (n = 109) of responses were from 84 subjects who participated in the elective. SBME-DP versus traditional education significantly improved fruit and vegetable diet (OR = 1.38, 95% CI: 1.07–1.79, p = 0.013) and attitudes (OR = 1.81, 95% CI: 1.40–2.35, p < 0.001) and competencies (OR = 1.72, 95% CI: 1.54–1.92, p < 0.001). Conclusions. This study reports for the first time superiority longitudinally for SBME-DP style nutrition education for medical students which has since expanded to 13 schools. PMID:26435851
Tam, Vernissia; Luketich, James D; Winger, Daniel G; Sarkaria, Inderpal S; Levy, Ryan M; Christie, Neil A; Awais, Omar; Shende, Manisha R; Nason, Katie S
2016-11-01
Postoperative infection increases cancer recurrence and worsens survival in colorectal cancer, but the relationship for esophagogastric adenocarcinoma after esophagectomy is not well defined. We aimed to determine whether recurrence and survival after minimally invasive esophagectomy for esophagogastric adenocarcinoma were influenced by postoperative infection using propensity-matched analysis. We abstracted data for 810 patients (1997-2010) and defined exposure as at least 1 in-hospital or 30-day infectious complication (n = 206 [25%]). Using 29 pretreatment/intraoperative variables, patients were propensity-score matched (caliper = 0.05). Time to cancer recurrence and survival (Kaplan-Meier curves and the Breslow test), and associated factors (Cox regression with shared frailty) were assessed. After propensity matching (n = 167 pairs), median bias across propensity-score variables was reduced from 12.9% (p < 0.001) to 4.4% (p = 1.000). Postoperative infection was not associated with rate (n = 60 versus 63; McNemar p = 0.736) or time to recurrence in those in whom disease recurred (median, 10.7 versus 11.1 months; Wilcoxon signed-rank p = 0.455) but was associated with shorter overall survival (n = 124 versus 102 deaths; median, 26 versus 41 months; Breslow p = 0.002). After adjusting for age, body mass index, neoadjuvant therapy, sex, comorbidity score, positive resection margins, pathologic stage, R0 resection, and recurrence, postoperative infection was associated with a 44% greater hazard for death (hazard ratio, 1.44; 95% confidence interval, 1.10-1.89). In patients with esophagogastric adenocarcinoma, infections after esophagectomy were not associated with an increased rate or earlier time to recurrence when baseline characteristics associated with infection risk were balanced using propensity-score matching. Despite this, overall survival was shorter in patients with infectious complications. After adjusting for other important survival predictors
Risk of brain herniation after craniotomy with lumbar spinal drainage: a propensity score analysis.
Motoyama, Yasushi; Nakajima, Tsukasa; Takamura, Yoshiaki; Nakazawa, Tsutomu; Wajima, Daisuke; Takeshima, Yasuhiro; Matsuda, Ryosuke; Tamura, Kentaro; Yamada, Shuichi; Yokota, Hiroshi; Nakagawa, Ichiro; Nishimura, Fumihiko; Park, Young-Su; Nakamura, Mitsutoshi; Nakase, Hiroyuki
2018-06-08
OBJECTIVE Lumbar spinal drainage (LSD) during neurosurgery can have an important effect by facilitating a smooth procedure when needed. However, LSD is quite invasive, and the pathology of brain herniation associated with LSD has become known recently. The objective of this study was to determine the risk of postoperative brain herniation after craniotomy with LSD in neurosurgery overall. METHODS Included were 239 patients who underwent craniotomy with LSD for various types of neurological diseases between January 2007 and December 2016. The authors performed propensity score matching to establish a proper control group taken from among 1424 patients who underwent craniotomy and met the inclusion criteria during the same period. The incidences of postoperative brain herniation between the patients who underwent craniotomy with LSD (group A, n = 239) and the matched patients who underwent craniotomy without LSD (group B, n = 239) were compared. RESULTS Brain herniation was observed in 24 patients in group A and 8 patients in group B (OR 3.21, 95% CI 1.36-8.46, p = 0.005), but the rate of favorable outcomes was higher in group A (OR 1.79, 95% CI 1.18-2.76, p = 0.005). Of the 24 patients, 18 had uncal herniation, 5 had central herniation, and 1 had uncal and subfalcine herniation; 8 patients with other than subarachnoid hemorrhage were included. Significant differences in the rates of deep approach (OR 5.12, 95% CI 1.8-14.5, p = 0.002) and temporal craniotomy (OR 10.2, 95% CI 2.3-44.8, p = 0.002) were found between the 2 subgroups (those with and those without herniation) in group A. In 5 patients, brain herniation proceeded even after external decompression (ED). Cox regression analysis revealed that the risk of brain herniation related to LSD increased with ED (hazard ratio 3.326, 95% CI 1.491-7.422, p < 0.001). Among all 1424 patients, ED resulted in progression or deterioration of brain herniation more frequently in those who underwent LSD than it did in those who
Use of disease risk scores in pharmacoepidemiologic studies.
Arbogast, Patrick G; Ray, Wayne A
2009-02-01
Automated databases are increasingly used in pharmacoepidemiologic studies. These databases include records of prescribed medications and encounters with medical care providers from which one can construct very detailed surrogate measures for both drug exposure and covariates that are potential confounders. Often it is possible to track day-by-day changes in these variables. However, while this information is often critical for study success, its volume can pose challenges for statistical analysis. One common approach is the use of propensity scores. An alternative approach is to construct a disease risk score. This is analogous to the propensity score in that it calculates a summary measure from the covariates. However, the disease risk score estimates the probability or rate of disease occurrence conditional on being unexposed. The association between exposure and disease is then estimated adjusting for the disease risk score in place of the individual covariates. This review describes the use of disease risk scores in pharmacoepidemiologic studies, and includes a brief discussion of their history, a more detailed description of their construction and use, a summary of simulation studies comparing their performance vis-á-vis traditional models, a comparison of their utility with that of propensity scores, and some further topics for future research.
Clerkin, Kevin J; Topkara, Veli K; Mancini, Donna M; Yuzefpolskaya, Melana; Demmer, Ryan T; Dizon, Jose M; Takeda, Koji; Takayama, Hiroo; Naka, Yoshifumi; Colombo, Paolo C; Garan, A Reshad
2017-06-01
Implantable cardioverter defibrillators (ICDs) provide a significant mortality benefit for appropriately selected patients with advanced heart failure. ICDs are associated with a mortality benefit when used in patients with a pulsatile left ventricular assist device (LVAD). It is unclear whether patients with a continuous-flow LVAD (CF-LVAD) derive the same benefit. We sought to determine if the presence of an ICD provided a mortality benefit during CF-LVAD support as a bridge to transplantation. Patients were identified in the United Network for Organ Sharing (UNOS) registry who underwent LVAD implantation as bridge to transplantation between May 2004 and April 2014, with follow-up through June 2014. Primary outcome was freedom from death while on CF-LVAD support with adjustment for complications requiring UNOS listing status upgrade. Secondary end-points included freedom from delisting while on CF-LVAD support and incidence of transplantation. The study cohort comprised 2,990 patients, and propensity score matching identified 1,012 patients with similar propensity scores. There was no difference in survival during device support between patients with and without an ICD (hazard ratio [HR] = 1.20; 95% confidence interval [CI], 0.66-2.17; p = 0.55). Adjusting for device complications requiring a UNOS listing status upgrade had minimal influence (HR = 1.11; 95% CI, 0.60-2.05; p = 0.74). There was no increased risk of delisting owing to being too sick for patients with an ICD (HR = 1.08; 95% CI, 0.63-1.86; p = 0.78). Likewise, the probability of transplantation was similar (HR = 1.05; 95% CI, 0.87-1.27; p = 0.62). Among patients bridged to transplantation with a CF-LVAD, the presence of an ICD did not reduce mortality. Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
Clerkin, Kevin J.; Topkara, Veli K.; Mancini, Donna M.; Yuzefpolskaya, Melana; Demmer, Ryan T.; Dizon, Jose M.; Takeda, Koji; Takayama, Hiroo; Naka, Yoshifumi; Colombo, Paolo C.; Garan, A. Reshad
2016-01-01
Background Implantable cardioverter defibrillators (ICD) provide a significant mortality benefit for appropriately selected patients with advanced heart failure. ICDs are associated with a mortality benefit when used in patients with a pulsatile left ventricular assist device (LVAD). However it is unclear whether patients with a continuous flow LVAD (CF-LVAD) derive the same benefit. This study sought to determine if the presence of an ICD provided a mortality benefit during CFLVAD support as a bridge to transplantation. Methods Patients were identified in the United Network for Organ Sharing (UNOS) registry that underwent LVAD implantation as bridge to transplantation from May 2004 and April 2014, with follow-up through June 2014. The primary outcome was freedom from death while on CF-LVAD support with adjustment for complications requiring UNOS listing status upgrade. Secondary endpoints included freedom from delisting while on CF-LVAD support and incidence of transplantation. Results 2,990 patients composed the study cohort and propensity score matching identified 1,012 patients with similar propensity scores. There was no difference in survival during device support between patients with and without an ICD (Hazard Ratio [HR] 1.20, 95% Confidence Interval [CI] 0.66-2.17, p=0.55). Adjusting for device complications requiring a UNOS listing status upgrade had minimal influence (HR 1.11, 95% CI 0.60-2.05, p=0.74). There was no increased risk of delisting due to being too sick for those with an ICD (HR 1.08, 95% CI 0.63-1.86, p=0.78). Likewise, the probability of transplantation was similar (HR 1.05, 95% CI 0.87-1.27, p=0.62). Conclusions Among patients bridged to transplantation with a CF-LVAD, the presence of an ICD did not reduce mortality. PMID:28089072
Jang, Mi-Ok; Jang, Hee-Chang; Kim, Uh Jin; Ahn, Joon Hwan; Kang, Seung-Ji; Jung, Sook-In; Shin, Hee-Young
2014-01-01
There are no well-matched, controlled studies comparing azithromycin with doxycycline for the treatment of complicated scrub typhus. A retrospective propensity score-matched case-control study was performed for patients who presented with complicated scrub typhus and were treated with doxycycline or azithromycin between 2001 and 2011. Data on comorbidities, clinical manifestations, laboratory studies, treatments, and outcomes were extracted for analysis. The clinical characteristics and outcomes of the azithromycin-treated group (n = 73) were compared to those of the doxycycline-treated group (n = 108). Of 181 patients, 73 from each group were matched by propensity scores. There were no significant differences in baseline characteristics between the matched groups. The treatment success and survival rates were not significantly different (89% [65/73 patients] versus 96% [70/73 patients] and 96% [70/73 patients] versus 96% [70/73 patients], respectively [P > 0.05]). No difference was observed in the time to defervescence or length of hospital stay between the two groups (P > 0.05). In complicated scrub typhus patients (n = 181), multivariate analysis showed that only APACHE II score was an independent risk factor for mortality (95% confidence interval, 1.11 to 1.56; P < 0.001). Our data suggest that outcomes of azithromycin therapy are comparable to those of doxycycline therapy in patients with complicated scrub typhus. PMID:24366734
Esaki, Mitsuru; Suzuki, Sho; Hayashi, Yasuyo; Yokoyama, Azusa; Abe, Shuichi; Hosokawa, Taizo; Ogino, Haruei; Akiho, Hirotada; Ihara, Eikichi; Ogawa, Yoshihiro
2018-02-27
Endoscopic submucosal dissection (ESD) is a standard treatment for early gastric cancer. A new multi-functional ESD device was developed to achieve complete ESD with a single device. A metal plate attached to its distal sheath achieves better hemostasis during the procedure than the other needle-knife device, Flush Knife BT®, that has been conventionally used. The aim of this study was to compare the technical outcomes of ESD for early gastric cancer using the Splash M-Knife® with those using the Flush Knife BT. We conducted a retrospective review of the case records of 149 patients with early gastric cancer treated with ESD using the needle-type ESD knives between January 2012 and August 2016 at Kitakyushu Municipal Medical Center. Lesions treated with ESD using the Splash M-knife (ESD-M) and the Flush Knife BT (ESD-F) were compared. Multivariate analyses and propensity score matching were used to compensate for the differences in age, gender, underlying disease, antithrombotic drug use, lesion location, lesion position, macroscopic type, tumor size, presence of ulceration, operator level and types of electrosurgical unit used. The primary endpoint was the requirement to use hemostatic forceps in the two groups. The secondary endpoints of procedure time, en bloc and complete resection rates, and adverse events rates were evaluated for the two groups. There were 73 patients in the ESD-M group, and 76 patients in the ESD-F group. Propensity score matching analysis created 45 matched pairs. Adjusted comparisons between the two groups showed a significantly lower usage rate of hemostatic forceps in the ESD-M group than in the ESD-F group (6.7% vs 84.4%, p < 0.001). Treatment outcomes showed an en bloc resection rate of 100% in both groups; complete resection rate of 95.6% vs 100%, p = 0.49; median procedure time of 74.0 min vs 71.0 min, p = 0.90; post-procedure bleeding of 2.2% vs 2.2%, p = 1, in the ESD-M and ESD-F groups, respectively. There were
Cerqueira, Rui J; Raimundo, Renata; Moreira, Soraia; Saraiva, Francisca A; Andrade, Marta; Salgueiro, Elson; Almeida, Jorge; Amorim, Mário Jorge; Pinho, Paulo; Lourenço, André P; Leite-Moreira, Adelino
2018-01-16
The goal of this study was to compare the stentless Freedom Solo® (FS) and the stented Trifecta® (TF) aortic bioprostheses with regard to haemodynamic profile, left ventricular mass regression and early and late postoperative outcomes and survival. A longitudinal cohort study of consecutive patients undergoing aortic valve replacement (2009-16) with either the FS or TF at 1 centre was performed. Local databases and national records were queried. Prosthesis haemodynamics and left ventricular dimensions were obtained from postoperative echocardiograms. After propensity score matching (21 covariates), the Kaplan-Meier and competing risk analyses were performed for survival and the combined outcome of structural valve deterioration and endocarditis, respectively. Haemodynamics and mass regression were assessed by a mixed-effects model including propensity score as a covariate. From a total sample of 397 patients with the FS and 525 TF bioprostheses with a median follow-up time of 4.0 (2.2-6.0) and 2.4 (1.4-3.7) years, respectively, a matched sample of 329 pairs was obtained. Matched groups showed no differences in survival (hazard ratio = 1.04, 95% confidence interval = 0.69-1.56) or cumulative hazards of combined outcome (subdistribution hazard ratio = 0.54, 95% confidence interval = 0.21-1.39). Although the TF showed an improved haemodynamic profile, no difference was found in mass regression. Patients with TF bioprostheses had higher rates of prolonged mechanical ventilation, whereas patients with the FS bioprosthesis showed higher rates of thrombocytopenia. The TF showed an improved haemodynamic profile compared to the FS, but this did not translate into further reverse remodelling. Postoperative outcomes and survival rates were comparable for both bioprostheses. Long-term follow-up is needed for comparisons with classical bioprosthesis models. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for
Chalikias, George; Tziakas, Dimitrios; Chizzolini, Carlo; Ribi, Camillo; Trendelenburg, Marten; Eisenberger, Ute; Hauser, Thomas; Pasch, Andreas; Huynh-Do, Uyen; Arampatzis, Spyridon
2018-01-01
Background Systemic lupus erythematosus (SLE) is associated with severe cardiovascular complications. The T50 score is a novel functional blood test quantifying calcification propensity in serum. High calcification propensity (or low T50) is a strong and independent determinant of all-cause mortality in various patient populations. Methods A total of 168 patients with ≥ 4 American College of Rheumatology (ACR) diagnostic criteria from the Swiss Systemic lupus erythematosus Cohort Study (SSCS) were included in this analysis. Serum calcification propensity was assessed using time-resolved nephelometry. Results The cohort mainly consisted of female (85%), middle-aged (43±14 years) Caucasians (77%). The major determinants of T50 levels included hemoglobin, serum creatinine and serum protein levels explaining 43% of the variation at baseline. Integrating disease activity (SELENA-SLEDAI) into this multivariate model revealed a significant association between disease activity and T50 levels. In a subgroup analysis considering only patients with active disease (SELENA-SLEDAI score ≥4) we found a negative association between T50 and SELENA-SLEDAI score at baseline (Spearman’s rho -0.233, P = 0.02). Conclusions Disease activity and T50 are closely associated. Moreover, T50 levels identify a subgroup of SLE patients with ongoing systemic inflammation as mirrored by increased disease activity. T50 could be a promising biomarker reflecting SLE disease activity and might offer an earlier detection tool for high-risk patients. PMID:29364894
Miyazaki, Takuro; Yamazaki, Takuya; Nakamura, Daisuke; Sato, Shuntaro; Yamasaki, Naoya; Tsuchiya, Tomoshi; Matsumoto, Keitaro; Kamohara, Ryotaro; Hatachi, Go; Nagayasu, Takeshi
2017-12-01
The aim of this study was to compare the outcomes of surgery and stereotactic body radiotherapy (SBRT) for elderly clinical stage I non-small cell lung cancer (NSCLC) patients. Patients ≥80 years of age with clinical stage I NSCLC between August 2008 and December 2014 were treated either surgery or SBRT. Propensity score matching was performed to reduce bias in various clinicopathological factors. Surgery was performed in 57 cases and SBRT in 41 cases. In the surgery group, the operations included 34 lobectomies and 23 sublobar resections. In the SBRT group, 27 cases were given 48 Gy in 4 fractions, and 14 were given 60 Gy in 10 fractions. Similar characteristics were identified in age (82 years), gender (male:female ratio 2:1), tumor size (2.2 cm), carcinoembryonic antigen (3.6 ng/ml), Charlson comorbidity index (1), Glasgow prognostic scale (0), and forced expiratory volume in 1 s (1.7 L) after matching. Before matching, the 5-year overall survival (OS) in surgery (68.3%) was significantly better than that in SBRT (47.4%, p = 0.02), and the 5-year disease-specific survival (DSS) (94.1%, 78.2%, p = 0.17) was not significantly different between the groups. The difference in the 5-year OS became non-significant between the matched pairs (57.0%, 49.1%, p = 0.56). The outcomes of surgery and SBRT for elderly patients with the early stage NSCLC were roughly the same.
López-Cortés, L E; Almirante, B; Cuenca-Estrella, M; Garnacho-Montero, J; Padilla, B; Puig-Asensio, M; Ruiz-Camps, I; Rodríguez-Baño, J
2016-08-01
We compared the clinical efficacy of fluconazole and echinocandins in the treatment of candidemia in real practice. The CANDIPOP study is a prospective, population-based cohort study on candidemia carried out between May 2010 and April 2011 in 29 Spanish hospitals. Using strict inclusion criteria, we separately compared the impact of empirical and targeted therapy with fluconazole or echinocandins on 30-day mortality. Cox regression, including a propensity score (PS) for receiving echinocandins, stratified analysis on the PS quartiles and PS-based matched analyses, were performed. The empirical and targeted therapy cohorts comprised 316 and 421 cases, respectively; 30-day mortality was 18.7% with fluconazole and 33.9% with echinocandins (p 0.02) in the empirical therapy group and 19.8% with fluconazole and 27.7% with echinocandins (p 0.06) in the targeted therapy group. Multivariate Cox regression analysis including PS showed that empirical therapy with fluconazole was associated with better prognosis (adjusted hazard ratio 0.38; 95% confidence interval 0.17-0.81; p 0.01); no differences were found within each PS quartile or in cases matched according to PS. Targeted therapy with fluconazole did not show a significant association with mortality in the Cox regression analysis (adjusted hazard ratio 0.77; 95% confidence interval 0.41-1.46; p 0.63), in the PS quartiles or in PS-matched cases. The results were similar among patients with severe sepsis and septic shock. Empirical or targeted treatment with fluconazole was not associated with increased 30-day mortality compared to echinocandins among adults with candidemia. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Clemens, Tom; Popham, Frank; Boyle, Paul
2015-02-01
There is a strong association between unemployment and mortality, but whether this relationship is causal remains debated. This study utilizes population-level administrative data from Scotland within a propensity score framework to explore whether the association between unemployment and mortality may be causal. The study examined a sample of working men and women aged 25-54 in 1991. Subsequent employment status in 2001 was observed (in work or unemployed) and the relative all-cause mortality risk of unemployment between 2001 and 2010 was estimated. To account for potential selection into unemployment of those in poor health, a propensity score matching approach was used. Matching variables were observed prior to unemployment and included health status up to the year of unemployment (hospital admissions and self-reported limiting long-term illness), as well as measures of socioeconomic position. Unemployment was associated with a significant all-cause mortality risk relative to employment for men (hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.33-2.55). This effect was robust to controlling for prior health and sociodemographic characteristics. Effects for women were smaller and statistically insignificant (HR 1.51; 95% CI 0.68-3.37). For men, the findings support the notion that the often-observed association between unemployment and mortality may contain a significant causal component; although for women, there is less support for this conclusion. However, female employment status, as recorded in the census, is more complex than for men and may have served to underestimate any mortality effect of unemployment. Future work should examine this issue further. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
Mojtabai, Ramin; Graff Zivin, Joshua
2003-01-01
Objective To assess the effectiveness and cost-effectiveness of four treatment modalities for substance abuse. Data Sources The study used data from the Services Research Outcomes Study (SROS), a survey of 3,047 clients in a random sample of 99 drug treatment facilities across the United States. Detailed sociodemographic, substance use, and clinical data were abstracted from treatment records. Substance abuse outcome and treatment history following discharge from index facilities were assessed using a comprehensive interview with 1,799 of these individuals five years after discharge. Treatment success was defined in two ways: as abstinence and as any reduction in substance use. Study Design Effectiveness and cost-effectiveness of four modalities were compared: inpatient, residential, outpatient detox/methadone, and outpatient drug-free. Clients were stratified based on propensity scores and analyses were conducted within these strata. Sensitivity analyses examined the impact of future substance abuse treatment on effectiveness and cost-effectiveness estimates. Principal Findings Treatment of substance disorders appears to be cost-effective compared to other health interventions. The cost per successfully treated abstinent case in the least costly modality, the outpatient drug-free programs, was $6,300 (95 percent confidence intervals: $5,200–$7,900) in 1990 dollars. There were only minor differences between various modalities of treatment with regard to effectiveness. However, modalities varied considerably with regard to cost-effectiveness. Outpatient drug-free programs were the most cost-effective. There was little evidence that relative effectiveness or cost-effectiveness of programs varied according to factors that were associated with selection into different programs. Conclusions Substance disorders can be treated most cost-effectively in outpatient drug-free settings. Savings from transitioning to the most cost-effective treatment modality may free
Szekér, Szabolcs; Vathy-Fogarassy, Ágnes
2018-01-01
Logistic regression based propensity score matching is a widely used method in case-control studies to select the individuals of the control group. This method creates a suitable control group if all factors affecting the output variable are known. However, if relevant latent variables exist as well, which are not taken into account during the calculations, the quality of the control group is uncertain. In this paper, we present a statistics-based research in which we try to determine the relationship between the accuracy of the logistic regression model and the uncertainty of the dependent variable of the control group defined by propensity score matching. Our analyses show that there is a linear correlation between the fit of the logistic regression model and the uncertainty of the output variable. In certain cases, a latent binary explanatory variable can result in a relative error of up to 70% in the prediction of the outcome variable. The observed phenomenon calls the attention of analysts to an important point, which must be taken into account when deducting conclusions.
Lee, Chung-Hsun; Hsieh, Chih-Chia; Hong, Ming-Yuan; Hung, Yuan-Pin; Ko, Wen-Chien; Lee, Ching-Chi
2017-05-01
In this study, the therapeutic efficacy of third-generation cephalosporins (3GCs) was compared with that of broader-spectrum β-lactams (BSBLs) [fourth-generation cephalosporins (4GCs) and carbapenems] as empirical therapy in adults with community-onset monomicrobial Enterobacteriaceae bacteraemia. Compared with those in the 3GC group (n = 477), a significantly higher proportion of patients in the BSBL group (n = 141) had initial presentation with severe sepsis or septic shock, critical illness (Pitt bacteraemia score ≥4) at bacteraemia onset and fatal co-morbidities (McCabe classification). For propensity score matching, 318 of the 477 patients in the 3GC group were matched with 106 patients in the BSBL group with the closest propensity scores on the basis of five independent predictors of 28-day mortality. After appropriate matching, no significant differences were observed in major baseline characteristics between the 3GC and BSBL groups in terms of causative micro-organism, bacteraemia severity, major source of bacteraemia, major co-morbidities and severity of co-morbidity. Consequently, the early clinical failure rate (12.9% vs. 12.3%; P = 0.87), bacteraemia severity (Pitt bacteraemia score ≥4; 4.6% vs. 8.2%; P = 0.17) at Day 3, and 3-day (3.8% vs. 7.5%; P = 0.11) and 28-day (13.2% vs. 17.0%; P = 0.33) crude mortality rates between the two groups were similar. These data suggest that the efficacy of 3GCs is similar to that of 4GCs or carbapenems when used as empirical antimicrobial therapy for community-onset Enterobacteriaceae bacteraemia. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.
Wu, Li-Rong; Zhu, Huan-Feng; Xu, Jianhua; Jiang, Xue-Song; Yin, Li; Jiang, Ning; Zong, Dan; Wang, Fei-Jiang; Huang, Sheng-Fu; Bian, Xiu-Hua; Wu, Jian-Feng; Song, Dan; Guo, Wen-Jie; Liu, Ju-Ying; He, Xia
2018-01-01
Background : This study aimed to compare concurrent chemoradiotherapy (CCRT) plus cetuximab (C) with CCRT alone in locoregionally advanced nasopharyngeal carcinoma(NPC). Methods : A total of 682 locoregionally advanced NPC patients who had undergone chemoradiotherapy with or without cetuximab were included. Propensity score-matching method was used to match patients. Progression-free survival (PFS), overall survival (OS), locoregional relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) were compared between the two treatment arms. Results : After matching, 225 patients were identified for the analysis. Compared to CCRT, CCRT plus C was associated with significantly improved 3-year PFS (83.7% vs 71.9%, P = 0.036), LRFS (98.6% vs 90.2%, P = 0.034) but not OS (91.4% vs 85.4%, P = 0.117). Among patients with T4 and/or N3 category, CCRT plus C significantly prolonged 3-year PFS (81.0% vs 61.4%, P = 0.022) and increased 3-year OS (88.0% vs 77.9%, P = 0.086). No significant differences were observed between CCRT plus C and CCRT alone groups with regard to 3-year PFS, OS, LRFS and DMFS rates in stage III patients. Acute oral and oropharyngeal mucositis during radiotherapy were more common in the CCRT plus C than that in CCRT, but late toxicities were comparable. Conclusions: This study reveals that patients with locoregionally advanced NPC could benefit from the addition of cetuximab to CCRT, and this therapeutic gain mainly originated from T4 and/or N3 subgroup although suffering more acute moderate to severe toxicities.
Sabashnikov, Anton; Patil, Nikhil P; Popov, Aron-Frederik; Soresi, Simona; Zych, Bartlomiej; Weymann, Alexander; Mohite, Prashant N; García Sáez, Diana; Zeriouh, Mohamed; Wahlers, Thorsten; Choi, Yeong-Hoon; Wippermann, Jens; Wittwer, Thorsten; De Robertis, Fabio; Bahrami, Toufan; Amrani, Mohamed; Simon, André R
2016-01-01
Due to organ shortage in lung transplantation (LTx), donation after circulatory death (DCD) has been implemented in several countries, contributing to an increasing number of organs transplanted. We sought to assess long-term outcomes after LTx with organs procured following circulatory death in comparison with those obtained from donors after brain death (DBD). Between January 2007 and November 2013, 302 LTxs were performed in our institution, whereby 60 (19.9%) organs were retrieved from DCD donors. We performed propensity score matching (DCD:DBD = 1:2) based on preoperative donor and recipient factors that were significantly different in univariate analysis. After propensity matching, there were no statistically significant differences between the groups in terms of demographics and preoperative donor and recipient characteristics. There were no significant differences regarding intraoperative variables and total ischaemic time. Patients from the DCD group had significantly higher incidence of primary graft dysfunction grade 3 at the end of the procedure (P = 0.014), and significantly lower pO2/FiO2 ratio during the first 24 h after the procedure (P = 0.018). There was a trend towards higher incidence of the need for postoperative extracorporeal life support in the DCD group. Other postoperative characteristics were comparable. While the overall cumulative survival was not significantly different, the DCD group had significantly poorer results in terms of bronchiolitis obliterans syndrome (BOS)-free survival in the long-term follow-up. Long-term results after LTx with organs procured following DCD are in general comparable with those obtained after DBD LTx. However, patients transplanted using organs from DCD donors have a predisposition for development of BOS in the longer follow-up. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
Tanaka, Marenao; Yamashita, Tomohisa; Koyama, Masayuki; Moniwa, Norihito; Ohno, Kohei; Mitsumata, Kaneto; Itoh, Takahito; Furuhashi, Masato; Ohnishi, Hirofumi; Yoshida, Hideaki; Tsuchihashi, Kazufumi; Miura, Tetsuji
2016-06-01
It is controversial whether treatment with an angiotensin II receptor blocker (ARB) or a calcium channel blocker (CCB) improves prognosis of hemodialysis (HD) patients. This study was designed as a multicenter prospective cohort study. HD patients (n = 1071) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data, kidney transplantation or retraction of consent during the follow-up period (n = 204) were excluded, and 867 patients contributed to analysis of mortality. Propensity score (PS) for use of ARB and that for CCB was calculated using a multiple logistic regression model. ARB and CCB were prescribed in 45.6 and 54.7 % of patients at enrollment. During the 3-year follow-up period, all-cause mortality and cardiovascular mortality rates were 18.8 and 5.1 %, respectively. Kaplan-Meier curves showed that all-cause and cardiovascular mortality rates were lower in the ARB group than in the non-ARB group, though the mortality rates were similar in the CCB group and non-CCB group. In PS-stratified Cox regression analysis, ARB treatment was associated with 34 and 45 % reduction of all-cause death and cardiovascular death, respectively. In PS matching analysis, ARB treatment was associated with a significant reduction (46 % reduction) in the risk of all-cause death. A significant impact of CCB treatment on all-cause or cardiovascular mortality was not detected in PS analysis. The use of an ARB, but not a CCB, is associated with reduced all-cause and cardiovascular mortalities in patients on HD.
Using ecological propensity score to adjust for missing confounders in small area studies.
Wang, Yingbo; Pirani, Monica; Hansell, Anna L; Richardson, Sylvia; Blangiardo, Marta
2017-11-09
Small area ecological studies are commonly used in epidemiology to assess the impact of area level risk factors on health outcomes when data are only available in an aggregated form. However, the resulting estimates are often biased due to unmeasured confounders, which typically are not available from the standard administrative registries used for these studies. Extra information on confounders can be provided through external data sets such as surveys or cohorts, where the data are available at the individual level rather than at the area level; however, such data typically lack the geographical coverage of administrative registries. We develop a framework of analysis which combines ecological and individual level data from different sources to provide an adjusted estimate of area level risk factors which is less biased. Our method (i) summarizes all available individual level confounders into an area level scalar variable, which we call ecological propensity score (EPS), (ii) implements a hierarchical structured approach to impute the values of EPS whenever they are missing, and (iii) includes the estimated and imputed EPS into the ecological regression linking the risk factors to the health outcome. Through a simulation study, we show that integrating individual level data into small area analyses via EPS is a promising method to reduce the bias intrinsic in ecological studies due to unmeasured confounders; we also apply the method to a real case study to evaluate the effect of air pollution on coronary heart disease hospital admissions in Greater London. © The Author 2017. Published by Oxford University Press.
Hill, Benjamin Mako; Shaw, Aaron
2013-01-01
Opt-in surveys are the most widespread method used to study participation in online communities, but produce biased results in the absence of adjustments for non-response. A 2008 survey conducted by the Wikimedia Foundation and United Nations University at Maastricht is the source of a frequently cited statistic that less than 13% of Wikipedia contributors are female. However, the same study suggested that only 39.9% of Wikipedia readers in the US were female - a finding contradicted by a representative survey of American adults by the Pew Research Center conducted less than two months later. Combining these two datasets through an application and extension of a propensity score estimation technique used to model survey non-response bias, we construct revised estimates, contingent on explicit assumptions, for several of the Wikimedia Foundation and United Nations University at Maastricht claims about Wikipedia editors. We estimate that the proportion of female US adult editors was 27.5% higher than the original study reported (22.7%, versus 17.8%), and that the total proportion of female editors was 26.8% higher (16.1%, versus 12.7%).
Wang, Shengfei; Huang, Yangle; Xie, Juntao; Zhuge, Lingdun; Shao, Longlong; Xiang, Jiaqing; Zhang, Yawei; Sun, Yihua; Hu, Hong; Chen, Sufeng; Lerut, Toni; Luketich, James D; Zhang, Jie; Chen, Haiquan
2018-03-01
Although endoscopic resection (ER) may be sufficient treatment for early-stage esophageal cancer, additional treatment is recommended when there is a high risk of cancer recurrence. It is unclear whether delaying esophagectomy by performing and assessing the success of ER affects outcomes as compared with immediate esophagectomy without ER. Additionally, long-term survival after sequential ER and esophagectomy required further investigation. Between 2011 and 2015, 48 patients with stage T1 esophageal cancer underwent esophagectomy after ER with curative intent at our institution. Two-to-one propensity score methods were used to identify 96 matched-control patients who were treated with esophagectomy only using baseline patient, tumor characteristics and surgical approach. Time from initial evaluation to esophagectomy, relapse-free survival, overall survival, and postoperative complications were compared between the propensity-matched groups. In the ER + esophagectomy group, the time from initial evaluation to esophagectomy was significantly longer than in the esophagectomy only group (114 vs. 8 days, p < 0.001). The incidence of dense adhesion (p = 0.347), operative time (p = 0.867), postoperative surgical complications (p = 0.966), and postoperative length of hospital stay (p = 0.125) were not significantly different between the groups. Moreover, recurrence-free survival and overall survival were also similar between the two groups (p = 0.411 and p = 0.817, respectively). Treatment of stage T1 esophageal cancer with ER prior to esophagectomy did not increase the difficulty of performing esophagectomy or the incidence of postoperative complications and did not affect survival after esophagectomy. These results suggest that ER can be recommended for patients with stage T1 cancer even if esophagectomy is warranted eventually.
Ferreira, Cesar Biselli; Bassi, Estevão; Lucena, Lucas; Carreta, Hernandez; Miranda, Leandro Costa; Tierno, Paulo Fernando Guimarães Mazorcchi; Amorim, Robson Luis; Zampieri, Fernando Godinho; Malbouisson, Luis Marcelo Sá
2015-01-01
To assess the impact of intracranial pressure monitoring on the short-term outcomes of traumatic brain injury patients. Retrospective observational study including 299 consecutive patients admitted due to traumatic brain injury from January 2011 through July 2012 at a Level 1 trauma center in São Paulo, Brazil. Patients were categorized in two groups according to the measurement of intracranial pressure (measured intracranial pressure and non-measured intracranial pressure groups). We applied a propensity-matched analysis to adjust for possible confounders (variables contained in the Crash Score prognostic algorithm). Global mortality at 14 days (16%) was equal to that observed in high-income countries in the CRASH Study and was better than expected based on the CRASH calculator score (20.6%), with a standardized mortality ratio of 0.77. A total of 28 patients received intracranial pressure monitoring (measured intracranial pressure group), of whom 26 were paired in a 1:1 fashion with patients from the non-measured intracranial pressure group. There was no improvement in the measured intracranial pressure group compared to the non-measured intracranial pressure group regarding hospital mortality, 14-day mortality, or combined hospital and chronic care facility mortality. Survival up to 14 days was also similar between groups. Patients receiving intracranial pressure monitoring tend to have more severe traumatic brain injuries. However, after adjusting for multiple confounders using propensity scoring, no benefits in terms of survival were observed among intracranial pressure-monitored patients and those managed with a systematic clinical protocol.
de Ribamar Costa, José; Abizaid, Alexandre; Bartorelli, Antonio L; Whitbourn, Robert; Jepson, Nigel; Perin, Marco; Steinwender, Clemens; Stuteville, Marrianne; Ediebah, Divine; Sudhir, Krishnankutty; Serruys, Patrick W
2016-11-20
We sought to compare the outcomes of low/moderate complexity patients treated with the Absorb BVS from the ABSORB EXTEND trial with patients treated with the XIENCE everolimus-eluting stent (EES), using propensity score (PS) matching of pooled data from the SPIRIT trials (SPIRIT II, SPIRIT III, SPIRIT IV) and the XIENCE V USA trial. ABSORB EXTEND was a prospective, single-arm, open-label clinical study in which 812 patients were enrolled at 56 sites. This study allowed the treatment of lesions ≤28 mm in length and with a reference vessel diameter of 2.0-3.8 mm (as assessed by online QCA). The propensity score was obtained by fitting a logistic regression model with the cohort indicator as the binary outcome and other variables as the predictor variables. At one-year clinical follow-up, there was no statistical difference between groups with regard to MACE (5.0% vs. 4.8%, p=0.83), target lesion failure (5.0% vs. 4.7%, p=0.74), ischaemia-driven target vessel revascularisation (2.3% vs. 3.0%, p=0.38) and device thrombosis (1.0% vs. 0.3%, p=0.11). Myocardial infarction was higher with Absorb (3.3% vs. 1.5%, p=0.02), at the expense of periprocedural CK-MB elevation. Independent predictors of MACE among patients receiving Absorb BVS were treatment of multivessel disease, insulin-dependent diabetes and performance of post-dilation. At one-year follow-up, propensity score-matched analysis demonstrated that the clinical safety and effectiveness of Absorb are comparable to those of XIENCE EES among non-complex patients treated with PCI.
Kohrt, B A; Burkey, M; Stuart, E A; Koirala, S
2015-01-01
Ethical, logistical, and funding approaches preclude conducting randomized control trials (RCTs) in some humanitarian crises. A lack of RCTs and other intervention research has contributed to a limited evidence-base for mental health and psychosocial support (MHPS) programs after disasters, war, and disease outbreaks. Propensity score methods (PSMs) are an alternative analysis technique with potential application for evaluating MHPS programs in humanitarian emergencies. PSMs were used to evaluate impacts of education reintegration packages (ERPs) and other (vocational or economic) reintegration packages (ORPs) v. no reintegration programs on mental health of child soldiers. Propensity scores were used to determine weighting of child soldiers in each of the three treatment arms. Multiple linear regression was used to estimate adjusted changes in symptom score severity on culturally validated measures of depression, post-traumatic stress disorder (PTSD), and functional impairment from baseline to 1-year follow-up. Among 258 Nepali child soldiers participating in reintegration programs, 54.7% completed ERP and 22.9% completed ORP. There was a non-significant reduction in depression by 0.59 (95% CI -1.97 to 0.70) for ERP and by 0.60 (95% CI -2.16 to 0.96) for ORP compared with no treatment. There were non-significant increases in PTSD (1.15, 95% CI -1.55 to 3.86) and functional impairment (0.91, 95% CI -0.31 to 2.14) associated with ERP and similar findings for ORP (PTSD: 0.66, 95% CI -2.24 to 3.57; functional impairment (1.05, 95% CI -0.71 to 2.80). In a humanitarian crisis in which a non-randomized intervention assignment protocol was employed, the statistical technique of PSMs addressed differences in covariate distribution between child soldiers who received different integration packages. Our analysis did not demonstrate significant changes in psychosocial outcomes for ERPs and ORPs. We suggest the use of PSMs in evaluating non-randomized interventions in
Helin-Salmivaara, Arja; Lavikainen, Piia; Aarnio, Emma; Huupponen, Risto; Korhonen, Maarit Jaana
2014-01-01
Sequential cohort design (SCD) applying matching for propensity scores (PS) in accrual periods has been proposed to mitigate bias caused by channeling when calendar time is a proxy for strong confounders. We studied the channeling of patients according to atorvastatin and simvastatin initiation in Finland, starting from the market introduction of atorvastatin in 1998, and explored the SCD PS approach to analyzing the comparative effectiveness of atorvastatin versus simvastatin in the prevention of cardiovascular events (CVE). Initiators of atorvastatin or simvastatin use in the 45-75-year age range in 1998-2006 were characterized by their propensity of receiving atorvastatin over simvastatin, as estimated for 17 six-month periods. Atorvastatin (10 mg) and simvastatin (20 mg) initiators were matched 1∶1 on the PS, as estimated for the whole cohort and within each period. Cox regression models were fitted conventionally, and also for the PS matched cohort and the periodically PS matched cohort, to estimate the hazard ratios (HR) for CVEs. Atorvastatin (10 mg) was associated with a 11%-12% lower incidence of CVE in comparison with simvastatin (20 mg). The HR estimates were the same for a conventional Cox model (0.88, 95% confidence interval 0.85-0.91), for the analysis in which the PS was used to match across all periods and the Cox model was adjusted for strong confounders (0.89, 0.85-0.92), and for the analysis in which PS matching was applied within sequential periods (0.88, 0.84-0.92). The HR from a traditional PS matched analysis was 0.80 (0.77-0.83). The SCD PS approach produced effect estimates similar to those obtained in matching for PS within the whole cohort and adjusting the outcome model for strong confounders, but at the cost of efficiency. A traditional PS matched analysis without further adjustment in the outcome model produced estimates further away from unity.
Ortiz, H; Ciga, M A; Armendariz, P; Kreisler, E; Codina-Cazador, A; Gomez-Barbadillo, J; Garcia-Granero, E; Roig, J V; Biondo, S
2014-06-01
Abdominal perineal excision (APE) was originally described with levator ani removal for rectal cancer. An even wider, more aggressive extralevator resection for APE has been proposed. Although some surgeons are performing a very wide 'extralevator APE (ELAPE)', there are few data to recommend it routinely. This multicentre study aimed to compare outcomes of APE and ELAPE. A multicentre propensity case-matched analysis comparing two surgical approaches (APE and ELAPE) was performed. All patients who underwent abdominoperineal resection of a rectal tumour were considered for the analysis. Tumour height was defined by magnetic resonance imaging measurement and patients with stage II-III tumours had neoadjuvant radiochemotherapy. Involvement of the circumferential resection margin (CRM) and intraoperative tumour perforation were the main outcome measures. A logistic regression model was used to study the relationship between the surgical approaches and outcomes. From January 2008 to March 2013 a total of 1909 consecutive patients underwent APE or ELAPE, of whom 914 matched patients (457 in each group) formed the cohort for analysis. Intraoperative tumour perforation occurred in 7.9 and 7.7 per cent of patients during APE and ELAPE respectively (P = 0.902), and there was CRM involvement in 13.1 and 13.6 per cent (P = 0.846). There were no differences between APE and ELAPE in terms of postoperative complication rates (52.3 versus 48.1 per cent; P = 0.209), need for reoperation (7.7 versus 7.0 per cent; P = 0.703), perineal wound problems (26.0 versus 21.9 per cent; P = 0.141), mortality rate (2.0 versus 2.0 per cent; P = 1.000) and local recurrence rate at 2 years (2.7 versus 5.6 per cent; P = 0.664). ELAPE does not improve rates of CRM involvement, intraoperative tumour perforation, local recurrence or mortality. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.
Kılıç, Suat; Kılıç, Sarah S; Baredes, Soly; Chan Woo Park, Richard; Mahmoud, Omar; Suh, Jeffrey D; Gray, Stacey T; Eloy, Jean Anderson
2018-03-01
The use of endoscopic resection as an alternative to open surgery for sinonasal malignancies has increased in the past 20 years. The National Cancer Database was queried for cases of sinonasal squamous cell carcinoma (SNSCC) without cervical or distant metastases that were treated surgically between 2010 and 2014. They were split into 2 groups based on surgical approach: open or endoscopic. Demographics, facility and insurance type, stage, tumor characteristics, postoperative treatment, 30-day readmission rate, 30- and 90-day mortality, and overall survival (OS) were compared between the 2 groups. Cox proportional hazard analysis was performed. Propensity score matching (PSM) was used to mimic a randomized, controlled trial. A total of 1,483 patients were identified: 353 (23.8%) received endoscopic and 1130 (76.2%) received open surgery. Age, gender, race, geographic region, tumor size, surgical margins, postoperative chemoradiation, and 30-day readmissions did not vary significantly between the 2 groups. Open surgery was more common in academic centers (62.8% vs 54.2%; p = 0.004), less common for tumors of the ethmoid and sphenoid sinus (p < 0.0001), less common for stage IVB tumors, and associated with longer hospital stay (mean, 4.67 days vs 2.50 days; p < 0.0001). Five-year OS (5Y-OS) was not significantly different between the 2 approaches (p = 0.953; open: 5Y-OS, 56.5%; 95% confidence interval, 51.3% to 61.6%; endoscopic: 5Y-OS, 46.0%; 95% confidence interval, 33.2% to 58.8%). In the PSM cohort of 652 patients, there was also no significant difference in OS (p = 0.850). Endoscopic surgery is an effective alternative to open surgery, even after accounting for confounding factors that may favor its use over the open approach. It is also associated with a shorter hospital stay. © 2017 ARS-AAOA, LLC.
Nohara, Kango; Takada, Kazuto; Kojima, Eiji; Ninomiya, Kiyoko; Miyamatsu, Shoko; Shimizu, Takahiro; Sakurai, Tsutomu; Mizuno, Takaaki; Yamashita, Yuuki
2016-09-01
The choice of an optimal sclerosant for pleurodesis for malignant pleural effusion remains controversial. This retrospective clinical study compared the efficacy and safety of two sclerosants; talc slurry (talc-s) and OK-432. We compared the characteristics, 30/90-day success rates, and adverse events in patients with lung adenocarcinoma who underwent pleurodesis by using either OK-432 or talc-s. Propensity score matching was used to compare the two scelrosants. Ninety-four patients (mean age=71.6±9.6 years) were included in this retrospective study, of whom 64 received OK-432 and 30 received talc-s. Seventy-three patients (77.6%) were initially diagnosed with clinical stage IV lung cancer, with a 28.7% epidermal growth factor receptor mutation frequency. The propensity score-matched cohort included 26 patients from each group. The 30-day success rates for OK-432 and talc-s were 80.7% and 76.9%, respectively (odds ratio: 1.26, 95% confidence interval: 0.33-4.77, p=0.73). Neither the overall incidence of adverse events nor the 90-day success rates differed significantly. Multivariate logistic regression revealed that the predictors of 30-day success were lower drainage volume on the previous day, particularly <250mL/day, the presence of full lung expansion, and pre-therapy with an epidermal growth factor receptor-tyrosine kinase inhibitor. The median post-pleurodesis survival time was 6.9 months, which was not significantly different between the study groups. Propensity score-matched analyses showed that pleurodesis using OK-432 and talc-s demonstrated comparable efficacy and safety profiles in patients with lung adenocarcinoma. This indicated that OK-432 could be a viable alternative to talc-s in this procedure. Copyright © 2016. Published by Elsevier B.V.
The Use of Propensity Scores in Mediation Analysis
ERIC Educational Resources Information Center
Jo, Booil; Stuart, Elizabeth A.; MacKinnon, David P.; Vinokur, Amiram D.
2011-01-01
Mediation analysis uses measures of hypothesized mediating variables to test theory for how a treatment achieves effects on outcomes and to improve subsequent treatments by identifying the most efficient treatment components. Most current mediation analysis methods rely on untested distributional and functional form assumptions for valid…
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sheu, Tommy; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Heymach, John V.
2014-11-15
Purpose: To retrospectively analyze factors influencing survival in patients with non-small cell lung cancer presenting with ≤3 synchronous metastatic lesions. Methods and Materials: We identified 90 patients presenting between 1998 and 2012 with non-small cell lung cancer and ≤3 metastatic lesions who had received at least 2 cycles of chemotherapy followed by surgery or radiation therapy before disease progression. The median number of chemotherapy cycles before comprehensive local therapy (CLT) (including concurrent chemoradiation as first-line therapy) was 6. Factors potentially affecting overall (OS) or progression-free survival (PFS) were evaluated with Cox proportional hazards regression. Propensity score matching was used to assessmore » the efficacy of CLT. Results: Median follow-up time was 46.6 months. Benefits in OS (27.1 vs 13.1 months) and PFS (11.3 months vs 8.0 months) were found with CLT, and the differences were statistically significant when propensity score matching was used (P ≤ .01). On adjusted analysis, CLT had a statistically significant benefit in terms of OS (hazard ratio, 0.37; 95% confidence interval, 0.20-0.70; P ≤ .01) but not PFS (P=.10). In an adjusted subgroup analysis of patients receiving CLT, favorable performance status (hazard ratio, 0.43; 95% confidence interval, 0.22-0.84; P=.01) was found to predict improved OS. Conclusions: Comprehensive local therapy was associated with improved OS in an adjusted analysis and seemed to favorably influence OS and PFS when factors such as N status, number of metastatic lesions, and disease sites were controlled for with propensity score–matched analysis. Patients with favorable performance status had improved outcomes with CLT. Ultimately, prospective, randomized trials are needed to provide definitive evidence as to the optimal treatment approach for this patient population.« less
Ivanecz, Arpad; Krebs, Bojan; Stozer, Andraz; Jagric, Tomaz; Plahuta, Irena; Potrc, Stojan
2018-03-01
The aim of the study was to compare the outcome of pure laparoscopic and open simultaneous resection of both the primary colorectal cancer and synchronous colorectal liver metastases (SCLM). From 2000 to 2016 all patients treated by simultaneous resection were assessed for entry in this single center, clinically nonrandomized trial. A propensity score matching was used to compare the laparoscopic group (LAP) to open surgery group (OPEN). Primary endpoints were perioperative and oncologic outcomes. Secondary endpoints were overall survival (OS) and disease-free survival (DFS). Of the 82 patients identified who underwent simultaneous liver resection for SCLM, 10 patients underwent LAP. All these consecutive patients from LAP were matched to 10 comparable OPEN. LAP reduced the length of hospital stay (P = 0.044) and solid food oral intake was faster (P = 0.006) in this group. No patient undergoing the laparoscopic procedure experienced conversion to the open technique. No difference was observed in operative time, blood loss, transfusion rate, narcotics requirement, clinical risk score, resection margin, R0 resections rate, morbidity, mortality and incisional hernias rate. The two groups did not differ significantly in terms of the 3-year OS rate (90 vs. 75%; P = 0.842) and DFS rate (60 vs. 57%; P = 0.724). LAP reduced the length of hospital stay and offers faster solid food oral intake. Comparable oncologic and survival outcomes can be achieved. LAP is beneficial for well selected patients in high volume centers with appropriate expertise.
Valente, Roberto; Sutcliffe, Robert; Levesque, Eric; Costa, Mara; De' Angelis, Nicola; Tayar, Claude; Cherqui, Daniel; Laurent, Alexis
2018-04-01
Laparoscopic left hemihepatectomy (LLH) may be an alternative to open (OLH). There are several original variations in the technical aspects of LLH, and no accepted standard. The aim of this study is to assess the safety and effectiveness of the technique developed at Henri Mondor Hospital since 1996. The technique of LLH was conceived for safety and training of two mature generations of lead surgeons. The technique includes full laparoscopy, ventral approach to the common trunk, extrahepatic pedicle dissection, CUSA ® parenchymal transection, division of the left hilar plate laterally to the Arantius ligament, and ventral transection of the left hepatic vein. The outcomes of LLH and OLH were compared. Perioperative analysis included intra- and postoperative, and histology variables. Propensity Score Matching was undertaken of background covariates including age, ASA, BMI, fibrosis, steatosis, tumour size, and specimen weight. 17 LLH and 51 OLH were performed from 1996 to 2014 with perioperative mortality rates of 0% and 6%, respectively. In the LLH group, two patients underwent conversion to open surgery. Propensity matching selected 10 LLH/OLH pairs. The LLH group had a higher proportion of procedures for benign disease. LLH was associated with longer operating time and less blood loss. Perioperative complications occurred in 30% (LLH) and 10% (OLH) (p = 1). Mortality and ITU stay were similar. This technique is recommended as a possible technical reference for standard LLH. Copyright © 2017 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.
Frankenstein, L; Katus, H A; Grundtvig, M; Hole, T; de Blois, J; Schellberg, D; Atar, D; Zugck, C; Agewall, S
2013-10-01
Heart failure (CHF) guidelines recommend mineralocorticoid receptor antagonists for all symptomatic patients treated with a combination of ACE inhibitors/angiotensin receptor blockers (ARBs) and beta-blockers. As opposed to both eplerenone trials, patients in RALES (spironolactone) received almost no beta-blockers. Since pharmacological properties differ between eplerenone and spironolactone, the prognostic benefit of spironolactone added to this baseline combination therapy needs clarification. We included 4,832 CHF patients with chronic systolic dysfunction from the Norwegian Heart Failure Registry and the heart failure outpatients' clinic of the University of Heidelberg. Propensity scores for spironolactone receipt were calculated for each patient and used for matching to patients without spironolactone. During a total follow-up of 17,869 patient-years, 881 patients (27.0 %) died in the non-spironolactone group and 445 (28.4 %) in the spironolactone group. Spironolactone was not associated with improved survival, neither in the complete sample (HR 0.82; 95 % CI 0.64-1.07; HR 1.03; 95 % CI 0.88-1.20; multivariate and propensity score adjusted respectively), nor in the propensity-matched cohort (HR 0.98; 95 % CI 0.82-1.18). In CHF outpatients we were unable to observe an association between the use of spironolactone and improved survival when administered in addition to a combination of ACE/ARB and beta-blockers.
Wong, Irene O L; Lindner, Michael J; Cowling, Benjamin J; Lau, Eric H Y; Lo, Su-Vui; Leung, Gabriel M
2010-04-01
To evaluate the presence of moral hazard, adjusted for the propensity to have self-purchased insurance policies, employer-based medical benefits, and welfare-associated medical benefits in Hong Kong. Based on 2005 population survey, we used logistic regression and zero-truncated negative binomial/Poisson regressions to assess the presence of moral hazard by comparing inpatient and outpatient utilization between insured and uninsured individuals. We fitted each enabling factor specific to the type of service covered, and adjusted for predisposing socioeconomic and demographic factors. We used a propensity score approach to account for potential adverse selection. Employment-based benefits coverage was associated with increased access and intensity of use for both inpatient and outpatient care, except for public hospital use. Similarly, welfare-based coverage had comparable effect sizes as employment-based schemes, except for the total number of public ambulatory episodes. Self-purchased insurance facilitated access but did not apparently induce greater demand of services among ever users. Nevertheless, there was no evidence of moral hazard in public hospital use. Our findings suggest that employment-based benefits coverage lead to the greatest degree of moral hazard in Hong Kong. Future studies should focus on confirming these observational findings using a randomized design. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.
Ferreira, Cesar Biselli; Bassi, Estevão; Lucena, Lucas; Carreta, Hernandez; Miranda, Leandro Costa; Tierno, Paulo Fernando Guimarães Mazorcchi; Amorim, Robson Luis; Zampieri, Fernando Godinho; Malbouisson, Luis Marcelo Sá
2015-01-01
Objective To assess the impact of intracranial pressure monitoring on the short-term outcomes of traumatic brain injury patients. Methods Retrospective observational study including 299 consecutive patients admitted due to traumatic brain injury from January 2011 through July 2012 at a Level 1 trauma center in São Paulo, Brazil. Patients were categorized in two groups according to the measurement of intracranial pressure (measured intracranial pressure and non-measured intracranial pressure groups). We applied a propensity-matched analysis to adjust for possible confounders (variables contained in the Crash Score prognostic algorithm). Results Global mortality at 14 days (16%) was equal to that observed in high-income countries in the CRASH Study and was better than expected based on the CRASH calculator score (20.6%), with a standardized mortality ratio of 0.77. A total of 28 patients received intracranial pressure monitoring (measured intracranial pressure group), of whom 26 were paired in a 1:1 fashion with patients from the non-measured intracranial pressure group. There was no improvement in the measured intracranial pressure group compared to the non-measured intracranial pressure group regarding hospital mortality, 14-day mortality, or combined hospital and chronic care facility mortality. Survival up to 14 days was also similar between groups. Conclusion Patients receiving intracranial pressure monitoring tend to have more severe traumatic brain injuries. However, after adjusting for multiple confounders using propensity scoring, no benefits in terms of survival were observed among intracranial pressure-monitored patients and those managed with a systematic clinical protocol. PMID:26761468
2013-01-01
Opt-in surveys are the most widespread method used to study participation in online communities, but produce biased results in the absence of adjustments for non-response. A 2008 survey conducted by the Wikimedia Foundation and United Nations University at Maastricht is the source of a frequently cited statistic that less than 13% of Wikipedia contributors are female. However, the same study suggested that only 39.9% of Wikipedia readers in the US were female – a finding contradicted by a representative survey of American adults by the Pew Research Center conducted less than two months later. Combining these two datasets through an application and extension of a propensity score estimation technique used to model survey non-response bias, we construct revised estimates, contingent on explicit assumptions, for several of the Wikimedia Foundation and United Nations University at Maastricht claims about Wikipedia editors. We estimate that the proportion of female US adult editors was 27.5% higher than the original study reported (22.7%, versus 17.8%), and that the total proportion of female editors was 26.8% higher (16.1%, versus 12.7%). PMID:23840366
Lee, Hakmin; Song, Byung D; Byun, Seok-Soo; Lee, Sang E; Hong, Sung K
2018-01-01
To analyse the effect of prolonged warm ischaemia time (WIT) on long-term renal function after partial nephrectomy (PN), as controversy still exists as to whether prolonged WIT adversely affects the incidence of chronic kidney disease (CKD) after PN. We reviewed data from 1816 patients who underwent PN for a clinical T1 renal tumour. The propensity scores for prolonged WIT were calculated with the shorter WIT group (<30 min) matched to the longer WIT group (≥30 min) in a 2:1 ratio. Multivariate analysis was used to determine independent predictors for occurrence of postoperative CKD [defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m 2 ] and major renal function deterioration (MRFD; defined as an eGFR decrease of ≥25% postoperatively). After propensity score matching, there was no significant difference in CKD-free survival between the two WIT groups (P = 0.787). Furthermore, longer WIT did not show any significant associations with postoperative CKD-free survival [hazard ratio (HR) 1.002, 95% confidence interval (CI) 0.989-1.015; P = 0.765) and MRFD-free survival (HR 1.014, 95% CI 1.000-1.028; P = 0.055). From further subgroup analyses using more specific WIT thresholds (≤20, 21-30, 31-40, 41-50, ≥50 min) and status of preoperative CKD, no significant differences were noted in CKD and MRFD-free survival amongst the subgroups (all P > 0.05). Prolonged WIT was not associated with increased incidence of CKD or MRFD after PN. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.
ERIC Educational Resources Information Center
Bersamin, Melina; Garbers, Samantha; Gaarde, Jenna; Santelli, John
2016-01-01
This study examines the association between school-based health center (SBHC) presence and school-wide measures of academic achievement and college preparation efforts. Publicly available educational and demographic data from 810 California public high schools were linked to a list of schools with an SBHC. Propensity score matching, a method to…
Jung, Sung Min; Yu, Chang Sik; Park, In Ja; Kim, Tae Won; Kim, Jong Hoon; Yoon, Yong Sik; Lim, Seok-Byung; Kim, Jin Cheon
2016-05-01
Good oncologic outcomes, demonstrated by a complete pathologic response after preoperative chemoradiotherapy (PCRT), have led to local excision (LE) in selected patients with rectal cancer. We evaluated the oncologic safety of LE compared with total mesorectal excision (TME) in patients with ypT0-T1 rectal cancer.A retrospective review of 304 patients who underwent PCRT, followed by LE or TME, for ypT0-T1 rectal cancer was performed. Propensity scores were computed and used to match groups (LE:TME = 1:1), and analysis of disease-free survival (DFS) and overall survival (OS) was made by comparing patients who underwent LE or TME. Prognostic factors of relapse were analyzed for all patients.Tumor categories were ypT0 in 25 (61.9%) cases, ypTis in 6 (14.3%) cases, and ypT1 in 11 (26.2%) cases for the LE group, and ypT0 in 28 (66.7%) cases, ypTis in 4 (9.5%) cases, and ypT1 in 10 (23.8%) cases for the matched TME patients. There was no significant difference between the matched LE and TME groups in relapse (4.8% and 7.14%, respectively; P = 0.646), 5-year DFS (95.2% vs 91.6%; P = 0.33) and 5-year OS (96.6% vs 88.0%; P = 0.238). In the multivariate Cox regression analysis, tumor distance from the anal verge (hazard ratio [HR] = 0.78; 95% confidence interval (CI) = 0.616-0.992) and the tumor grade (HR = 4.29; 95% CI = 1.430-12.886) were significantly associated with the recurrence risk.LE results in oncologic outcomes that are comparable to those achieved by TME in selected patients with ypT0-T1 rectal cancer after PCRT.
Vidal, Sarah; Steeger, Christine M; Caron, Colleen; Lasher, Leanne; Connell, Christian M
2017-11-01
Multisystemic therapy (MST) was developed to help youth with serious social, emotional, and behavioral problems. Research on the efficacy and effectiveness of MST has shown positive outcomes in different domains of development and functioning among various populations of youth. Nonetheless, even with a large body of literature investigating the treatment effects of MST, few studies have focused on the effectiveness of MST through large-scale dissemination efforts. Utilizing a large sample of youth involved in a statewide dissemination of MST (n = 740; 43% females; 14% Black; 29% Hispanic; 49% White; M age = 14.9 years), propensity score matching was employed to account for baseline differences between the treatment (n = 577) and comparison (n = 163) groups. Treatment effects were examined based on three outcomes: out-of-home placement, adjudication, and placement in a juvenile training school over a 6-year period. Significant group differences remained after adjusting for baseline differences, with youth who received MST experiencing better outcomes in offending rates than youth who did not have an opportunity to complete MST due to non-clinical or administrative reasons. Survival analyses revealed rates of all three outcomes were approximately 40% lower among the treatment group. Overall, this study adds to the body of literature supporting the long-term effectiveness of MST in reducing offending among high-risk youth. The findings underscore the potential benefits of taking evidence-based programs such as MST to scale to improve the well-being and functioning of high-risk youth. However, strategies to effectively deliver the program in mental health service settings, and to address the specific needs of high-risk youth are necessary.
Jennings, Wesley G; Richards, Tara N; Smith, M Dwayne; Bjerregaard, Beth; Fogel, Sondra J
2015-07-01
A small body of prior research has examined the impact of victim sex on jury death penalty decision-making and the majority of this research has demonstrated some evidence of a "female victim effect" such that cases involving a female victim are more likely to receive the death penalty than similarly situated cases with a male victim. However, within this line of research studies have suggested that victim sex may work in conjunction with other case characteristics. In order to further explore this phenomenon, the current study examines a near-population of death penalty cases from North Carolina (n=1069) from 1977-2009 using propensity score matching. Results demonstrate that once cases are matched on more than 50 legal and extralegal case characteristics, there is no statistically significant or substantive link between victim sex and death penalty decision-making. Findings suggest that it is concrete differences in the legal and extralegal factors observed in cases with female victims compared to male victims that shape jury death sentence decisions rather than a direct effect of victim sex (before matching: OR=1.53; 95% CI=1.20-1.95; p<.001/after matching: OR=0.90; 95% CI=0.66-1.24; p=.52). Study limitations and implications are also discussed. Copyright © 2015 Elsevier Inc. All rights reserved.
Christiansen, Erik; Agerbo, Esben; Bilenberg, Niels; Stenager, Elsebeth
2016-01-01
SSRIs are widely used in the treatment of mental illness for both children and adults. Studies have found a slightly increased risk of suicidal thoughts and suicide attempts in young people using SSRIs but SSRIs' impact on risk for suicides in youth is not well-established. Is there indication that SSRIs might raise risk for suicide attempts in young people? We used an observational register-based historical cohort design, a large cohort of all Danish individuals born in 1983-1989 (n = 392,458) and a propensity score approach to analyse the impact from SSRIs on risk for suicide attempts. Every suicide attempt and redeemed prescription of SSRIs was analysed by Cox regression. We found a significant overlap between redeeming a prescription on SSRIs and subsequent suicide attempt. The risk for suicide attempt was highest in the first 3 months after redeeming the first prescription. The hazard ratio for suicide attempts after redeeming a prescription was estimated to 5.23, 95% CI 4.82-5.68. We conclude that the risk of suicide attempt is higher for young people in the first months after redeeming their first prescription for SSRIs, compared to non-users. For SSRI users with lower propensity score (fewer risk factors for SSRIs) the risk of suicide attempt is estimated to be highest. Although the design may miss some explicit reason for prescription of SSRIs and SSRIs might be a marker for those in high risk rather than a causal risk factor, we would recommend systematic risk assessment in the period after redeeming the first prescription.
Tsai, Laura Cordisco
2016-04-27
This study explores the causal impact of independent management of household finances upon women's experiences of intimate partner violence (IPV) in the Philippines. Propensity score matching is used to generate a casual estimate of the impact of women's roles as household financial managers on their experiences of IPV. Findings demonstrate that managing household finances independently significantly increased the severity of IPV women experienced from their partners compared with women who managed finances jointly with partners. Findings reinforce the importance of explicit attention to intrahousehold power dynamics and gender norms in the implementation of microfinance interventions intended to empower women. © The Author(s) 2016.
Kurokawa, Satoshi; Umemoto, Yukihiro; Mizuno, Kentaro; Okada, Atsushi; Nakane, Akihiro; Nishio, Hidenori; Hamamoto, Shuzo; Ando, Ryosuke; Kawai, Noriyasu; Tozawa, Keiichi; Hayashi, Yutaro; Yasui, Takahiro
2017-11-21
Robot-assisted radical prostatectomy (RARP) is commonly performed using the transperitoneal (TP) approach with six trocars over an 8-cm distance in the steep Trendelenburg position. In this study, we investigated the feasibility and the benefit of using the extraperitoneal (EP) approach with six trocars over a 4-cm distance in a flat or 5° Trendelenburg position. We also introduced four new steps to the surgical procedure and compared the surgical results and complications between the EP and TP approach using propensity score matching. Between August 2012 and August 2016, 200 consecutive patients without any physical restrictions underwent RARP with the EP approach in a less than 5° Trendelenburg position, and 428 consecutive patients underwent RARP with the TP approach in a steep Trendelenburg position. Four new steps to RARP using the EP approach were developed: 1) arranging six trocars; 2) creating the EP space using laparoscopic forceps; 3) holding the separated prostate in the EP space outside the robotic view; and 4) preventing a postoperative inguinal hernia. Clinicopathological results and complications were compared between the EP and TP approaches using propensity score matching. Propensity scores were calculated for each patient using multivariate logistic regression based on the preoperative covariates. All 200 patients safely underwent RARP using the EP approach. The mean volume of estimated blood loss and duration of indwelling urethral catheter use were significantly lower with the EP approach than the TP approach (139.9 vs 184.9 mL, p = 0.03 and 5.6 vs 7.7 days, p < 0.01, respectively). No significant differences in the positive surgical margin were observed. None of the patients developed an inguinal hernia postoperatively after we introduced this technique. The EP approach to RARP was safely performed regardless of patient physique or contraindications to a steep Trendelenburg position. Our method, which involved using the EP approach
Chatterjee, Satabdi; Chen, Hua; Johnson, Michael L; Aparasu, Rajender R
2012-10-01
Atypical antipsychotic agents have been associated with cerebrovascular adverse events, particularly in elderly dementia patients. However, limited evidence exists regarding comparative cerebrovascular profiles of individual atypical agents, particularly in community settings. The objective of this study was to evaluate the risk of cerebrovascular events associated with use of risperidone, olanzapine and quetiapine in community-dwelling older adults in the US. A propensity score-adjusted retrospective cohort design involving the IMS LifeLink™ Health Plan Claims Database was used for the study. The study population included all older adults (aged ≥50 years) who initiated risperidone, olanzapine or quetiapine anytime during 1 July 2000 to 30 June 2008. Patients were followed until hospitalization or an emergency room visit for a cerebrovascular event, or the end of the study period, whichever occurred earlier. The Cox proportional hazard regression model with time-varying covariates was used to evaluate the risk of cerebrovascular events during the follow-up period, using olanzapine as the reference. The covariates adjusted for in the final model included multiple propensity scores and exposure to other medications that could be associated with the risk of cerebrovascular events. A total of 2,458 cerebrovascular events were identified in the study cohort: 1,081 (21.38%) for risperidone users, 816 (18.75%) for olanzapine users and 561 (21.05%) for quetiapine users. After adjusting for propensity scores and other covariates, the Cox proportional hazard model revealed that use of quetiapine [hazard ratio (HR) 0.88; 95% CI 0.78, 0.99] but not risperidone (HR 1.05; 95% CI 0.95, 1.16) was associated with a decrease in the risk of cerebrovascular adverse events compared with olanzapine. The study suggested that quetiapine use may be associated with a moderately lower risk of cerebrovascular events than olanzapine in older adults. Prescribers should closely monitor the
Pilotto, Sara; Sperduti, Isabella; Leuzzi, Giovanni; Chiappetta, Marco; Mucilli, Felice; Ratto, Giovanni Battista; Lococo, Filippo; Filosso, Pier Lugigi; Spaggiari, Lorenzo; Novello, Silvia; Milella, Michele; Santo, Antonio; Scarpa, Aldo; Infante, Maurizio; Tortora, Giampaolo; Facciolo, Francesco; Bria, Emilio
2018-04-01
We developed one of the first clinicopathological prognostic nomograms for resected squamous cell lung cancer (SQLC). Herein, we validate the model in a larger multicenter cohort and we explore the impact of adjuvant and neoadjuvant treatment (ANT). Patients with resected SQLC from January 2002 to December 2012 in six institutions were eligible. Each patient was assigned a prognostic score based on the clinicopathological factors included in the model (age, T descriptor according to seventh edition of the TNM classification, lymph node status, and grading). Kaplan-Meier analysis for disease-free survival, cancer-specific survival (CSS), and overall survival was performed according to a three-class risk model. Harrell's C-statistics were adopted for model validation. The effect of ANT was adjusted with propensity score. Data on 1375 patients were gathered (median age, 68 years; male sex, 86.8%; T descriptor 1 or 2 versus 3 or 4, 71.7% versus 24.9%; nodes negative versus positive, 53.4% versus 46.6%; and grading of 1 or 2 versus 3, 35.0% versus 41.1%). Data for survival analysis were available for 1097 patients. With a median follow-up of 55 months, patients at low risk had a significantly longer disease-free survival than did patients at intermediate risk (hazard ratio [HR] = 1.67, 95% confidence interval [CI]: 1.40-2.01) and patients at high risk (HR = 2.46, 95% CI: 1.90-3.19); they also had a significantly longer CSS (HR = 2.46, 95% CI: 1.80-3.36 versus HR = 4.30, 95% CI: 2.92-6.33) and overall survival (HR = 1.79, 95% CI: 1.48-2.17 versus HR = 2.33, 95% CI: 1.76-3.07). A trend in favor of ANT was observed for intermediate-risk/high-risk patients, particularly for CSS (p = 0.06 [5-year CSS 72.7% versus 60.8%]). A model based on a combination of easily available clinicopathological factors effectively stratifies patients with resected SQLC into three risk classes. Copyright © 2017 International Association for the Study of Lung Cancer. Published by
Xia, Yang; Gu, Yeqing; Yu, Fei; Zhang, Qing; Liu, Li; Meng, Ge; Wu, Hongmei; Du, Huanmin; Shi, Hongbin; Guo, Xiaoyan; Liu, Xing; Li, Chunlei; Han, Peipei; Dong, Renwei; Wang, Xiuyang; Bao, Xue; Su, Qian; Fang, Liyun; Liu, Fangfang; Yang, Huijun; Kang, Li; Ma, Yixuan; Yu, Bin; Sun, Shaomei; Wang, Xing; Zhou, Ming; Jia, Qiyu; Guo, Qi; Wu, Yuntang; Song, Kun; Huang, Guowei; Wang, Guolin; Niu, Kaijun
2016-10-06
Previous studies indicated that dietary patterns were associated with metabolic syndrome (MS), but little is known in Chinese. We design this case-control study to evaluate the associations between dietary patterns and MS in Chinese adults. In this study, 1492 participants with MS were matched with 1492 controls using the 1:1 ratio propensity score matching methods. Dietary intake was assessed using a valid self-administered food frequency questionnaire, and MS was defined in accordance with the criteria of the American Heart Association scientific statement of 2009. Higher scores for the high-protein/cholesterol pattern were associated with higher prevalence of MS. Compared with the participants in the lowest quartile, the odds ratio (OR) for the extreme quartile was 1.36 (95% confidence interval (CI), 1.10-1.68) and the P for trend <0.01 after adjusted for the other two dietary pattern scores. We also found a moderate consumption of the balanced pattern was associated with the lowest prevalence of MS. The ORs across quartiles of the balanced pattern were 1 (reference), 0.83 (95% CI, 0.68-1.02), 0.69 (95% CI, 0.56-0.85), and 0.84 (95% CI, 0.68-1.04) after adjustment. Our study demonstrates that there is a strong association between a diet rich in animal offal, animal blood, meat, and sausage and a higher prevalence of MS.
de Vocht, Frank; Lee, Brian
2014-08-01
Studies have suggested that residential exposure to extremely low frequency (50 Hz) electromagnetic fields (ELF-EMF) from high voltage cables, overhead power lines, electricity substations or towers are associated with reduced birth weight and may be associated with adverse birth outcomes or even miscarriages. We previously conducted a study of 140,356 singleton live births between 2004 and 2008 in Northwest England, which suggested that close residential proximity (≤ 50 m) to ELF-EMF sources was associated with reduced average birth weight of 212 g (95%CI: -395 to -29 g) but not with statistically significant increased risks for other adverse perinatal outcomes. However, the cohort was limited by missing data for most potentially confounding variables including maternal smoking during pregnancy, which was only available for a small subgroup, while also residual confounding could not be excluded. This study, using the same cohort, was conducted to minimize the effects of these problems using multiple imputation to address missing data and propensity score matching to minimize residual confounding. Missing data were imputed using multiple imputation using chained equations to generate five datasets. For each dataset 115 exposed women (residing ≤ 50 m from a residential ELF-EMF source) were propensity score matched to 1150 unexposed women. After doubly robust confounder adjustment, close proximity to a residential ELF-EMF source remained associated with a reduction in birth weight of -116 g (95% confidence interval: -224:-7 g). No effect was found for proximity ≤ 100 m compared to women living further away. These results indicate that although the effect size was about half of the effect previously reported, close maternal residential proximity to sources of ELF-EMF remained associated with suboptimal fetal growth. Copyright © 2014 Elsevier Ltd. All rights reserved.
Uchida, K; Nishimura, T; Takesada, H; Morioka, T; Hagawa, N; Yamamoto, T; Kaga, S; Terada, T; Shinyama, N; Yamamoto, H; Mizobata, Y
2017-08-01
The purpose of this study was to assess the effects of recent surgical rib fixation and establish its indications not only for flail chest but also for multiple rib fractures. Between 2007 and 2015, 187 patients were diagnosed as having multiple rib fractures in our institution. After the propensity score matching was performed, ten patients who had performed surgical rib fixation and ten patients who had treated with non-operative management were included. Categorical variables were analyzed with Fischer's exact test and non-parametric numerical data were compared using the Mann-Whitney U test. Wilcoxon signed-rank test was performed for comparison of pre- and postoperative variables. All statistical data are presented as median (25-75 % interquartile range [IQR]) or number. The surgically treated patients extubated significantly earlier than non-operative management patients (5.5 [1-8] vs 9 [7-12] days: p = 0.019). The duration of continuous intravenous narcotic agents infusion days (4.5 [3-6] vs 12 [9-14] days: p = 0.002) and the duration of intensive care unit stay (6.5 [3-9] vs 12 [8-14] days: p = 0.008) were also significantly shorter in surgically treated patients. Under the same ventilating conditions, the postoperative values of tidal volume and respiratory rate improved significantly compared to those values measured just before the surgery. The incidence of pneumonia as a complication was significantly higher in non-operative management group (p = 0.05). From the viewpoints of early respiratory stabilization and intensive care unit disposition without any complications, surgical rib fixation is a sufficiently acceptable procedure not only for flail chest but also for repair of severe multiple rib fractures.
Busch, J; Gonzalgo, M; Leva, N; Ferrari, M; Friedersdorff, F; Hinz, S; Kempkensteffen, C; Miller, K; Magheli, A
2015-01-01
The optimal surgical treatment of patients with a high risk prostate cancer (PCa) in terms of radical prostatectomy (RP) is still controversial: open retropubic RP (RRP), laparoscopic RP (LRP), or robot-assisted (RARP). We aimed to investigate the influence of the different surgical techniques on pathologic outcome and biochemical recurrence. A total of 805 patients with a high risk PCa (PSA >20 ng/mL, Gleason Score ≥8, or clinical stage ≥cT2c) were included. A comparison of 407 RRP patients with 398 minimally invasive cases (LRP+RARP) revealed significant confounders. Therefore all 110 RARP cases were propensity score (PS) matched 1:1 with LRP and RRP patients. PS included age, clinical stage, preoperative PSA, biopsy Gleason score, surgeon's experience and application of a nerve sparing technique. Comparison of overall survival (OS) and recurrence-free survival (RFS) was done with the log rank test. Predictors of RFS were analyzed by means of Cox regression models. Within the post-matching cohort of 330 patients a pathologic Gleason score < 7, = 7 and > 7 was found in 1.8, 55.5 and 42.7% for RARP, in 8.2, 36.4, 55.5% for LRP and in 0, 60.9 and 39.1% for RRP (p=0.004 for RARP vs. LRP and p=0.398 for RARP vs. RRP). Differences in histopathologic stages were not statistically significant. The overall positive surgical margin rate (PSM) as well as PSM for ≥ pT3 were not different. PSM among patients with pT2 was found in 15.7, 14.0 and 20.0% for RARP, LRP and RRP (statistically not significant). The respective mean 3-year RFS rates were 41.4, 77.9, 54.1% (p<0.0001 for RARP vs. LRP and p=0.686 for RARP vs. RRP). The mean 3-year OS was calculated as 95.4, 98.1 and 100% respectively (statistically not significant). RARP for patients with a high risk PCa reveals similar pathologic and oncologic outcomes compared with LRP and RRP. © Georg Thieme Verlag KG Stuttgart · New York.
Analyzing Propensity Matched Zero-Inflated Count Outcomes in Observational Studies
DeSantis, Stacia M.; Lazaridis, Christos; Ji, Shuang; Spinale, Francis G.
2013-01-01
Determining the effectiveness of different treatments from observational data, which are characterized by imbalance between groups due to lack of randomization, is challenging. Propensity matching is often used to rectify imbalances among prognostic variables. However, there are no guidelines on how appropriately to analyze group matched data when the outcome is a zero inflated count. In addition, there is debate over whether to account for correlation of responses induced by matching, and/or whether to adjust for variables used in generating the propensity score in the final analysis. The aim of this research is to compare covariate unadjusted and adjusted zero-inflated Poisson models that do and do not account for the correlation. A simulation study is conducted, demonstrating that it is necessary to adjust for potential residual confounding, but that accounting for correlation is less important. The methods are applied to a biomedical research data set. PMID:24298197
Fibla, Juan J; Brunelli, Alessandro; Allen, Mark S; Wigle, Dennis; Shen, Robert; Nichols, Francis; Deschamps, Claude; Cassivi, Stephen D
2015-02-01
Our objective was to evaluate whether the number and volume of surgical lung biopsies (SLB) influence the diagnosis of diffuse interstitial lung disease (ILD). Retrospective study of SLB for suspected ILD in patients from the Mayo Clinic from January 2002 to January 2010. Data were collected in the institution and analyzed. 311 patients were studied. Mean number of biopsies was 2.05 (SD 0.6); 1 biopsy in 50 (16%), 2 in 198 (63.7%), 3 in 59 (19%) and 4 in 4 (1.3%). Histopathologic diagnosis was: definitive (specific): 232 (74.6%), descriptive (non-specific): 76 (24.4%), no diagnosis: 3 (1%). After excluding patients without diagnosis (n=3), there were 50 patients with only 1 biopsy, 196 with 2 and 62 with 3 or 4; the definitive diagnostic yield was similar in all 3 groups (37/50; 74%, 150/196; 77%, and 45/62; 73%) (Chi-square, p value 0.8). The propensity score analysis between patients with 1 SLB and patients with more than 1 SLB also showed no difference in diagnostic yield. Regarding the volume of biopsies, mean total volume was 34.4 cm(3) (SD 46): 41.2 cm(3) (3 cases) in patients with no diagnosis; 33.6 cm(3) (232 cases, SD 47) in patients with specific diagnosis; and 36.6 cm(3) (76 cases, SD 44) in patients with descriptive diagnosis. Biopsy volume had no influence on histopathology yield (ANOVA, p value .8). The number and volume of the biopsy specimens in SLB did not seem to influence diagnosis. Based on our results, we believe a single sample from a representative area may be sufficient for diagnosis. Randomized prospective trials should be performed to optimize SLB for ILD. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.
Janas, Adam; Buszman, Piotr P; Milewski, Krzysztof P; Wiernek, Szymon; Janas, Ksenia; Pruski, Maciej; Wojakowski, Wojciech; Błachut, Aleksandra; Picheta, Wojciech; Buszman, Pawel; Kiesz, Stefan
2017-02-24
The impact of endovascular revascularization of the lower extremity arteries with atherectomy (AT) compared with percutaneous transluminal angioplasty (PTA) is still unclear. Therefore, the aim of the study was to compare long-term outcomes after percutaneous PTA and AT in patients requiring endovascular revascularization.Methods and Results:This was a single-center, retrospective registry of obstructive and symptomatic PAD patients who underwent endovascular revascularization. PTA was performed in 215 patients, and AT in 204 (Silver Hawk, EV3, n=125; CSI 360°, n=66; Pathway Medical Technologies, n=13). There were no significant between-group differences in baseline characteristics except for increased CAD, dialysis and CLI prevalence in the PTA group. Following propensity score analysis 131 well-matched pairs were included in analysis. Bail-out stenting was more frequent in the reference group (PTA, 6.1% vs. AT, 0%; P=0.004). At 6- and 12-month follow-up there were no differences in TLR between the groups (PTA, 8.3% vs. AT, 5.3%; P=0.47; and PTA, 16.7% vs. AT, 13.7%; P=0.73, respectively). The difference was in favor of AT at 24-month follow-up (PTA, 29.0% vs. AT, 16.7%; P=0.05). No difference was observed in amputation rate (PTA, 0.7% vs AT, 1.5%; P=0.62). On Kaplan-Meier analysis there were no significant differences between groups in time to TLR, amputation or death. AT was associated with lower risk of TLR, and this should be confirmed in randomized controlled trials.
Kawakatsu, Yoshito; Sugishita, Tomohiko; Oruenjo, Kennedy; Wakhule, Stephen; Kibosia, Kennedy; Were, Eric; Honda, Sumihisa
2015-12-01
Mother and Child Health handbooks (MCH handbooks) serve as useful health education tools for mothers and sources of information that allow health care professionals to understand patient status. Therefore, it is necessary to clarify the effectiveness of and identify the factors related to possession of an MCH handbook among parents in rural Western Kenya using propensity score matching (PSM). A community-based cross-sectional survey using a structured questionnaire was conducted in rural western Kenya from August to September, 2011. We targeted 2560 mothers with children aged 12-24 months. Both PSM and multivariate logistic analyses were used in this study. Impacts of 5.9, 9.4, and 12.6 percentage points for higher health knowledge and for proper health-seeking behavior for fever and diarrhea, respectively, were statistically significant. The significant factors affecting possession of the MCH Handbook were the child's sex, the caregiver's relationship to the child, maternal age, health knowledge, birth interval, household wealth index and CHW performance accordingly. An MCH handbook was an effective tool for improving both health knowledge and health-seeking behavior in Kenya. The further distribution and utilization of an MCH handbook is expected to be an effective way to improve both maternal and child health. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Simone, Giuseppe; Tuderti, Gabriele; Misuraca, Leonardo; Anceschi, Umberto; Ferriero, Mariaconsiglia; Minisola, Francesco; Guaglianone, Salvatore; Gallucci, Michele
2018-04-17
In this study, we compared perioperative and oncologic outcomes of patients treated with either open or robot-assisted radical cystectomy and intracorporeal neobladder at a tertiary care center. The institutional prospective bladder cancer database was queried for "cystectomy with curative intent" and "neobladder". All patients underwent robot-assisted radical cystectomy and intracorporeal neobladder or open radical cystectomy and orthotopic neobladder for high-grade non-muscle invasive bladder cancer or muscle invasive bladder cancer with a follow-up length ≥2 years were included. A 1:1 propensity score matching analysis was used. Kaplan-Meier method was performed to compare oncologic outcomes of selected cohorts. Survival rates were computed at 1,2,3 and 4 years after surgery and the log rank test was applied to assess statistical significance between the matched groups. Overall, 363 patients (299 open and 64 robotic) were included. Open radical cystectomy patients were more frequently male (p = 0.08), with higher pT stages (p = 0.003), lower incidence of urothelial histologies (p = 0.05) and lesser adoption of neoadjuvant chemotherapy (<0.001). After applying the propensity score matching, 64 robot-assisted radical cystectomy patients were matched with 46 open radical cystectomy cases (all p ≥ 0.22). Open cohort showed a higher rate of perioperative overall complications (91.3% vs 42.2%, p 0.001). At Kaplan-Meier analysis robotic and open cohorts displayed comparable disease-free survival (log-rank p = 0.746), cancer-specific survival (p = 0.753) and overall-survival rates (p = 0.909). Robot-assisted radical cystectomy and intracorporeal neobladder provides comparable oncologic outcomes of open radical cystectomy and orthotopic neobladder at intermediate term survival analysis. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.
Edner, Magnus; Benson, Lina; Dahlström, Ulf; Lund, Lars H
2015-09-07
In heart failure (HF) with reduced ejection fraction (EF), renin-angiotensin receptor (RAS) antagonists reduce mortality. However, severe renal insufficiency was an exclusion criterion in trials. We tested the hypothesis that RAS antagonists are associated with reduced mortality also in HF with severe renal insufficiency. We studied patients with EF ≤39% registered in the prospective Swedish Heart Failure Registry. In patients with creatinine >221 µmol/L or creatinine clearance <30 mL/min, propensity scores for RAS-antagonist use were derived from 36 variables. The association between RAS antagonist use and all-cause mortality was assessed with Cox regression in a cohort matched 1:1 based on age and propensity score. To assess consistency, we performed the same analysis as a 'positive control' in patients without severe renal insufficiency. Between 2000 and 2013, there were 24 283 patients of which 2410 [age, mean (SD), 82 (9), 45% women] had creatinine >221 µmol/L or creatinine clearance <30 mL/min and were treated (n = 1602) or not treated (n = 808) with RAS antagonists. In the matched cohort of 602 vs. 602 patients [age 83 (8), 42% women], RAS antagonist use was associated with 55% [95% confidence interval (CI) 51-59] vs. 45% (41-49) 1-year survival, P < 0.001, with a hazard ratio (HR) for mortality of 0.76 (95% CI 0.67-0.86, P < 0.001). In positive control patients without severe renal insufficiency [n = 21 873; age 71 (12), 27% women], the matched HR was 0.79 (95% CI 0.72-0.86, P < 0.001). In HF with severe renal insufficiency, the use of RAS antagonists was associated with lower all-cause mortality. Prospective randomized trials are needed before these findings can be applied to clinical practice. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.
Fingolimod vs dimethyl fumarate in multiple sclerosis: A real-world propensity score-matched study.
Prosperini, Luca; Lucchini, Matteo; Haggiag, Shalom; Bellantonio, Paolo; Bianco, Assunta; Buscarinu, Maria Chiara; Buttari, Fabio; Centonze, Diego; Cortese, Antonio; De Giglio, Laura; Fantozzi, Roberta; Ferraro, Elisabetta; Fornasiero, Arianna; Francia, Ada; Galgani, Simonetta; Gasperini, Claudio; Marfia, Girolama Alessandra; Millefiorini, Enrico; Nociti, Viviana; Pontecorvo, Simona; Pozzilli, Carlo; Ruggieri, Serena; Salvetti, Marco; Sgarlata, Eleonora; Mirabella, Massimiliano
2018-06-06
To directly compare fingolimod (FNG) and dimethyl fumarate (DMF) on no evident disease activity (NEDA) status in patients with relapsing-remitting multiple sclerosis (RRMS) from 7 multiple sclerosis outpatient clinics in Central Italy. We analyzed data of patients with RRMS who started an oral agent, namely DMF or FNG, either as first treatment (naives) or after switching from self-injectable drugs (switchers). We performed a propensity score (PS)-based nearest-neighbor matching within a caliper of 0.05 to select patients with homogeneous baseline characteristics. Pairwise censoring was adopted to adjust for difference in length of follow-up between the 2 treatment groups. Comparisons were then conducted in matched samples with Cox models (stratified by center) with NEDA-3 as the main outcome. NEDA-3 was defined as no relapses, no disability worsening, and no MRI activity. Overall, 483 and 456 patients eligible for analysis started on FNG and DMF, respectively. The PS-matching procedure retained a total of 550 patients (275 per group). After a median on-study follow-up of 18 months, the proportions of patients with NEDA-3 were similar (FNG 73%, DMF 70%; hazard ratio [HR] 0.74, p = 0.078). Subgroup analyses showed a comparable effectiveness of the 2 drugs in naives (n = 170, HR 1.15, p = 0.689), whereas FNG was superior to DMF in the achievement of NEDA-3 status among switchers (n = 380, HR 0.57, p = 0.007). We found no significant difference between FNG and DMF on NEDA-3 status, while subgroup analyses suggest the superiority of FNG over DMF in patients switching from self-injectable drugs. This study provides Class IV evidence that for patients with RRMS, DMF and FNG have comparable efficacy in treatment-naive patients and that FNG is superior to DMF in patients switching from self-injectable drugs. © 2018 American Academy of Neurology.
Huang, Ting-Shuo; Huang, Shie-Shian; Shyu, Yu-Chiau; Lee, Chun-Hui; Jwo, Shyh-Chuan; Chen, Pei-Jer; Chen, Huang-Yang
2014-01-01
Procalcitonin (PCT)-based algorithms have been used to guide antibiotic therapy in several clinical settings. However, evidence supporting PCT-based algorithms for secondary peritonitis after emergency surgery is scanty. In this study, we aimed to investigate whether a PCT-based algorithm could safely reduce antibiotic exposure in this population. From April 2012 to March 2013, patients that had secondary peritonitis diagnosed at the emergency department and underwent emergency surgery were screened for eligibility. PCT levels were obtained pre-operatively, on post-operative days 1, 3, 5, and 7, and on subsequent days if needed. Antibiotics were discontinued if PCT was <1.0 ng/mL or decreased by 80% versus day 1, with resolution of clinical signs. Primary endpoints were time to discontinuation of intravenous antibiotics for the first episode and adverse events. Historical controls were retrieved for propensity score matching. After matching, 30 patients in the PCT group and 60 in the control were included for analysis. The median duration of antibiotic exposure in PCT group was 3.4 days (interquartile range [IQR] 2.2 days), while 6.1 days (IQR 3.2 days) in control (p < 0.001). The PCT algorithm significantly improves time to antibiotic discontinuation (p < 0.001, log-rank test). The rates of adverse events were comparable between 2 groups. Multivariate-adjusted extended Cox model demonstrated that the PCT-based algorithm was significantly associated with a 87% reduction in hazard of antibiotic exposure within 7 days (hazard ratio [HR] 0.13, 95% CI 0.07-0.21, p < 0.001), and a 68% reduction in hazard after 7 days (adjusted HR 0.32, 95% CI 0.11-0.99, p = 0.047). Advanced age, coexisting pulmonary diseases, and higher severity of illness were significantly associated with longer durations of antibiotic use. The PCT-based algorithm safely reduces antibiotic exposure in this study. Further randomized trials are needed to confirm our findings and incorporate cost
Rau, Cheng-Shyuan; Wu, Shao-Chun; Chen, Yi-Chun; Chien, Peng-Chen; Hsieh, Hsiao-Yun; Kuo, Pao-Jen; Hsieh, Ching-Hua
2017-11-13
Background: The most widely used methods of describing traumatic brain injury (TBI) are the Glasgow Coma Scale (GCS) and the Abbreviated Injury Scale (AIS). Recent evidence suggests that presenting GCS in older patients may be higher than that in younger patients for an equivalent anatomical severity of TBI. This study aimed to assess these observations with a propensity-score matching approach using the data from Trauma Registry System in a Level I trauma center. Methods: We included all adult patients (aged ≥20 years old) with moderate to severe TBI from 1 January 2009 to 31 December 2016. Patients were categorized into elderly (aged ≥65 years) and young adults (aged 20-64 years). The severity of TBI was defined by an AIS score in the head (AIS 3‒4 and 5 indicate moderate and severe TBI, respectively). We examined the differences in the GCS scores by age at each head AIS score. Unpaired Student's t - and Mann-Whitney U -tests were used to analyze normally and non-normally distributed continuous data, respectively. Categorical data were compared using either the Pearson chi-square or two-sided Fisher's exact tests. Matched patient populations were allocated in a 1:1 ratio according to the propensity scores calculated using NCSS software with the following covariates: sex, pre-existing chronic obstructive pulmonary disease, systolic blood pressure, hemoglobin, sodium, glucose, and alcohol level. Logistic regression was used to evaluate the effects of age on the GCS score in each head AIS stratum. Results: The study population included 2081 adult patients with moderate to severe TBI. These patients were categorized into elderly ( n = 847) and young adults ( n = 1234): each was exclusively further divided into three groups of patients with head AIS of 3, 4, or 5. In the 162 well-balanced pairs of TBI patients with head AIS of 3, the elderly demonstrated a significantly higher GCS score than the young adults (14.1 ± 2.2 vs. 13.1 ± 3.3, respectively; p = 0
Slade, Eric P; Stuart, Elizabeth A; Salkever, David S; Karakus, Mustafa; Green, Kerry M; Ialongo, Nicholas
2008-05-01
Age of onset of substance use disorders in adolescence and early adulthood could be associated with higher rates of adult criminal incarceration in the U.S., but evidence of these associations is scarce. Propensity score matching was used to estimate the association between adolescent-onset substance use disorders and the rate of incarceration, as well as incarceration costs and self-reported criminal arrests and convictions, of young men predominantly from African American, lower income, urban households. Age of onset was differentiated by whether onset of the first disorder occurred by age 16. Onset of a substance use disorder by age 16, but not later onset, was associated with a fourfold greater risk of adult incarceration for substance related offenses as compared to no disorder (0.35 vs. 0.09, P=0.044). Onset by age 16 and later onset were both positively associated with incarceration costs and risk of arrest and conviction, though associations with crime outcomes were more consistent with respect to onset by age 16. Results were robust to propensity score adjustment for observable predictors of substance use in adolescence and involvement in crime as an adult. Among young men in this high risk minority sample, having a substance use disorder by age 16 was associated with higher risk of incarceration for substance related offenses in early adulthood and with more extensive criminal justice system involvement as compared to having no disorder or having a disorder beginning at a later age.
Maccagni, Davide; Benincasa, Susanna; Bellini, Barbara; Candilio, Luciano; Poletti, Enrico; Carlino, Mauro; Colombo, Antonio; Azzalini, Lorenzo
2018-03-23
Chronic total occlusions (CTO) percutaneous coronary intervention (PCI) is associated with high radiation dose. Our study aim was to evaluate the impact of the implementation of a noise reduction technology (NRT) on patient radiation dose during CTO PCI. A total of 187 CTO PCIs performed between February 2016 and May 2017 were analyzed according to the angiographic systems utilized: Standard (n = 60) versus NRT (n = 127). Propensity score matching (PSM) was performed to control for differences in baseline characteristics. Primary endpoints were Cumulative Air Kerma at Interventional Reference Point (AK at IRP), which correlates with patient's tissue reactions; and Kerma Area Product (KAP), a surrogate measure of patient's risk of stochastic radiation effects. An Efficiency Index (defined as fluoroscopy time/AK at IRP) was calculated for each procedure. Image quality was evaluated using a 5-grade Likert-like scale. After PSM, n = 55 pairs were identified. Baseline and angiographic characteristics were well matched between groups. Compared to the Standard system, NRT was associated with lower AK at IRP [2.38 (1.80-3.66) vs. 3.24 (2.04-5.09) Gy, p = 0.035], a trend towards reduction for KAP [161 (93-244) vs. 203 (136-363) Gycm 2 , p = 0.069], and a better Efficiency Index [16.75 (12.73-26.27) vs. 13.58 (9.92-17.63) min/Gy, p = 0.003]. Image quality was similar between the two groups (4.39 ± 0.53 Standard vs. 4.34 ± 0.47 NRT, p = 0.571). In conclusion, compared with a Standard system, the use of NRT in CTO PCI is associated with lower patient radiation dose and similar image quality.
Chen, Szu-Ta; Wu, Meng-Che; Hsu, Tzu-Chun; Yen, Debra W; Chang, Chia-Na; Hsu, Wan-Ting; Wang, Chia-Chun; Lee, Matthew; Liu, Shing-Hwa; Lee, Chien-Chang
2018-03-01
Population-based studies evaluating outcomes of different approaches for rectal cancer are scarce. We conducted a retrospective cohort study using the Nationwide Inpatient Sample database between 2008 and 2012. We compared the outcomes and costs among rectal cancer patients undergoing robotic, laparoscopic, or open surgeries using propensity scores for adjusted and matched analysis. We identified 194 957 rectal cancer patients. Over the 5-year period, the annual admission number decreased by 13.9%, the in-hospital mortality rate decreased by 32.2%, while the total hospitalization cost increased by 13.6%. Compared with laparoscopic surgery, robotic surgery had significantly lower length of stay (LOS) (OR 0.69, 95%CI 0.57-0.84), comparable wound complications (OR 1.08, 95%CI 0.70-1.65) and higher cost (OR 1.42, 95%CI 1.13-1.79), while open surgery had significantly longer LOS (OR 1.38, 95%CI 1.19-1.59), more wound complications (OR 1.49, 95%CI 1.08-1.79), and comparable cost (OR 0.92, 95%CI 0.79-1.07). There were no difference in in-hospital mortality among three approaches. Laparoscopic surgery was associated with better outcomes than open surgery. Robotic surgery was associated with higher cost, but no advantage over laparoscopic surgery in terms of mortality and complications. Studies on cost-effectiveness of robotic surgery may be warranted. © 2017 Wiley Periodicals, Inc.
Miyata, Kei; Ohnishi, Hirofumi; Maekawa, Kunihiko; Mikami, Takeshi; Akiyama, Yukinori; Iihoshi, Satoshi; Wanibuchi, Masahiko; Mikuni, Nobuhiro; Uemura, Shuji; Tanno, Katsutoshi; Narimatsu, Eichi; Asai, Yasufumi
2016-02-01
In patients with severe traumatic brain injury (TBI), a randomized controlled trial revealed that outcomes did not significantly improve after therapeutic hypothermia (TH) or normothermia (TN). However, avoiding pyrexia, which is often associated with intracranial disorders, might improve clinical outcomes. The objective of this study was to compare neurological outcomes among patients with moderate and severe TBI after therapeutic temperature modulation (TTM) in the absence of other interventions. Data from 1091 patients were obtained from the Japan Neurotrauma Data Bank Project 2009, a cohort observational study. Patients with cardiac arrest, those with a Glasgow Coma Scale score of 3 and dilated fixed pupils, and those whose cause of death was injury to another area of the body were excluded, leaving 687 patients aged 16 years or older in this study. The patients were divided into 2 groups: the TTM group underwent TN (213 patients) or TH (82 patients), and the control group (392 patients) did not receive TTM. The primary end point for this study was the rate of poor outcome at hospital discharge, and the secondary end point was in-hospital death. Out of the 208 total items in the database, 29 variables that could potentially affect outcome were matched using the propensity score (PS) method in order to reduce selection bias and balance the baseline characteristics. From each group, 141 patients were extracted using the PS-matching process. Among the patients in the TTM group, 29 had undergone TH and 112 had undergone TN. In a log-rank test using Kaplan-Meier survival curves, no significant differences in patient outcome or death were observed between the 2 groups (poor outcome, p = 0.83; death, p = 0.18). A Cox proportional-hazards regression analysis established the HR for poor outcome and mortality at 1.03 (95% CI 0.78-1.36, p = 0.83) and 1.34 (95% CI 0.87-2.07, p = 0.18), respectively. There was no clear improvement in neurological outcomes after TTM in
Ikegami, Shota; Takahashi, Jun; Misawa, Hiromichi; Tsutsumimoto, Takahiro; Yui, Mutsuki; Kuraishi, Shugo; Futatsugi, Toshimasa; Uehara, Masashi; Oba, Hiroki; Kato, Hiroyuki
2018-05-01
There is little information on the relationship between magnetic resonance imaging (MRI) T2-weighted high signal change (T2HSC) in the spinal cord and surgical outcome for cervical myelopathy. We therefore examined whether T2HSC regression at 1 year postoperatively reflected a 5-year prognosis after adjustment using propensity scores for potential confounding variables, which have been a disadvantage of earlier observational studies. The objective of this study was to clarify the usefulness of MRI signal changes for the prediction of midterm surgical outcome in patients with cervical myelopathy. This is a retrospective cohort study. We recruited 137 patients with cervical myelopathy who had undergone surgery between 2007 and 2012 at a median age of 69 years (range: 39-87 years). The outcome measures were the recovery rates of the Japanese Orthopaedic Association (JOA) scores and the visual analog scale (VAS) scores for complaints at several body regions. The subjects were divided according to the spinal MRI results at 1 year post surgery into the MRI regression group (Reg+ group, 37 cases) with fading of T2HSC, or the non-regression group (Reg- group, 100 cases) with either no change or an enlargement of T2HSC. The recovery rates of JOA scores from 1 to 5 years postoperatively along with the 5-year postoperative VAS scores were compared between the groups using t test. Outcome scores were adjusted for age, sex, diagnosis, symptom duration, and preoperative JOA score by the inverse probability weighting method using propensity scores. The mean recovery rates in the Reg- group were 35.1%, 34.6%, 27.6%, 28.0%, and 30.1% from 1 to 5 years post surgery, respectively, whereas those in the Reg+ group were 52.0%, 52.0%, 51.1%, 49.0%, and 50.1%, respectively. The recovery rates in the Reg+ group were significantly higher at all observation points. At 5 years postoperatively, the VAS score for pain or numbnessin the arms or hands of the patients in the Reg+ group (24.7
Laborde-Castérot, Hervé; Agrinier, Nelly; Thilly, Nathalie
2015-10-01
Propensity score (PS) and instrumental variable (IV) are analytical techniques used to adjust for confounding in observational research. More and more, they seem to be used simultaneously in studies evaluating health interventions. The present review aimed to analyze the agreement between PS and IV results in medical research published to date. Review of all published observational studies that evaluated a clinical intervention using simultaneously PS and IV analyses, as identified in MEDLINE and Web of Science. Thirty-seven studies, most of them published during the previous 5 years, reported 55 comparisons between results from PS and IV analyses. There was a slight/fair agreement between the methods [Cohen's kappa coefficient = 0.21 (95% confidence interval: 0.00, 0.41)]. In 23 cases (42%), results were nonsignificant for one method and significant for the other, and IV analysis results were nonsignificant in most situations (87%). Discrepancies are frequent between PS and IV analyses and can be interpreted in various ways. This suggests that researchers should carefully consider their analytical choices, and readers should be cautious when interpreting results, until further studies clarify the respective roles of the two methods in observational comparative effectiveness research. Copyright © 2015 Elsevier Inc. All rights reserved.
Hoshino, Masato; Omura, Nobuo; Yano, Fumiaki; Tsuboi, Kazuto; Yamamoto, Se Ryung; Akimoto, Shunsuke; Masuda, Takahiro; Kashiwagi, Hideyuki; Yanaga, Katsuhiko
2017-12-01
The modalities for evaluating acid reflux in medical care for gastroesophageal reflux disease (GERD) include conventional pH (C-pH), wireless pH (Bravo ® ) and multichannel intraluminal impedance pH (MII-pH), which have been reported to vary with respect to the duration of acid reflux. In this study, we examined the difference between the acid reflux in C-pH and MII-pH among patients with GERD. Prior to initial laparoscopic fundoplication carried out on 297 cases from December 1994 to April 2016, an upper gastrointestinal endoscopy and C-pH or MII-pH were conducted. A propensity score-matched analysis was carried out about five factors including age, sex, BMI, the extent of reflux esophagitis (Los Angeles classification), and the presence of hiatal hernia (HH), ultimately leading to the creation of a C-pH group (81 cases) and MII-pH group (81 cases) as the subjects. Concerning pH < 4 holding time (18.9 vs. 7.3%, p < 0.001), DeMeester score (58.5 vs. 24.4, p < 0.001), and the number of times reflux continued for longer than 5 min (8.8 vs. 4.1 times/day, p = 0.002), the C-pH group had significantly higher values for each, while the positive rate of acid reflux (Positive pH) was significantly higher in the C-pH group (p < 0.001), at 80% in the C-pH group and 42% in the MII-pH group. In terms of the correlation between the extent of reflux esophagitis and pH < 4 holding time, a moderate level of positive correlation was seen in both the C-pH group and MII-pH group (r of each = 0.427, r = 0.408); moreover, regardless of the presence of HH, the holding time was significantly higher in the C-pH group than the MII-pH group (p of each <0.001, p = 0.040). While the values of each parameter regarding acid reflux are calculated as lower in MII-pH than in C-pH, there is no difference in the evaluation of the pathology between the two modalities.
McMillan, Matthew T.; Zureikat, Amer H.; Hogg, Melissa E.; Kowalsky, Stacy J.; Zeh, Herbert J.; Sprys, Michael H.
2016-01-01
Importance The adoption of robotic pancreatoduodenectomy (RPD) is gaining momentum; however, its impact on major outcomes, including pancreatic fistula, has yet to be adequately compared with open pancreatoduodenectomy (OPD). Objective To demonstrate that use of RPD does not increase the incidence of clinically relevant pancreatic fistula (CR-POPF) compared with OPD. Design, Setting, and Participants Data were accrued from 2846 patients who underwent pancreatoduodenectomies (OPDs, n = 2661; RPDs, n = 185), performed by 51 surgeons at 17 institutions worldwide (2003-2015). All RPDs were conducted at a high-volume, academic, pancreatic surgery specialty center—in a standardized fashion—by surgeons who had surpassed the RPD learning curve. Propensity score matching was used to minimize bias from nonrandomized treatment assignment. The RPD and OPD cohorts were matched by propensity scores accounting for factors significantly associated with either undergoing robotic surgery or CR-POPF occurrence on logistic regression analysis. These variables included pancreatic gland texture, pancreatic duct diameter, intraoperative blood loss, pathologic findings of disease, and intraoperative drain placement. Interventions Use of RPD or OPD. Main Outcomes and Measures The major outcome of interest was CR-POPF occurrence, which is the most common and morbid complication following pancreatoduodenectomy. Results The overall cohort was 51.5% male, with a median age of 64 years (interquartile range, 56-72 years). The propensity score–matched cohort comprised 152 RPDs and 152 OPDs; all covariate imbalances were alleviated. After adjusting for potential confounders, undergoing RPD was associated with a reduced risk for CR-POPF incidence (OR, 0.4 [95% CI, 0.2-0.7]; P = .002) relative to OPD. Other predictors of risk-adjusted CR-POPF occurrence included soft pancreatic parenchyma (OR, 4.7 [95% CI, 3.4-6.6]; P < .001), pathologic findings of high-risk disease (OR, 1.4 [95% CI
Gu, Xiaobin; Gao, Xianshu; Cui, Ming; Xie, Mu; Ma, Mingwei; Qin, Shangbin; Li, Xiaoying; Qi, Xin; Bai, Yun; Wang, Dian
2018-01-01
Objective This study was aimed to compare survival outcomes in high-risk prostate cancer (PCa) patients receiving external beam radiotherapy (EBRT) or radical prostatectomy (RP). Materials and methods The Surveillance, Epidemiology, and End Results (SEER) database was used to identify PCa patients with high-risk features who received RP alone or EBRT alone from 2004 to 2008. Propensity-score matching (PSM) was performed. Kaplan–Meier survival analysis was used to compare cancer-specific survival (CSS) and overall survival (OS). Multivariate Cox regression analysis was used to identify independent prognostic factors. Results A total of 24,293 patients were identified, 14,460 patients receiving RP and 9833 patients receiving EBRT. Through PSM, 3828 patients were identified in each group. The mean CSS was 128.6 and 126.7 months for RP and EBRT groups, respectively (P<0.001). The subgroup analyses showed that CSS of the RP group was better than that of the EBRT group for patients aged <65 years (P<0.001), White race (P<0.001), and married status (P<0.001). However, there was no significant difference in CSS for patients aged ≥65 years, Black race, other race, and unmarried status. Similar trends were observed for OS. Multivariate analysis showed that EBRT treatment modality, T3–T4 stage, Gleason score 8–10, and prostate-specific antigen >20 ng/mL were significant risk factors for both CSS and OS. Conclusion This study suggested that survival outcomes might be better with RP than EBRT in high-risk PCa patients aged <65 years; however, RP and EBRT provided equivalent survival outcomes in older patients, which argues for primary radiotherapy in this older cohort.
Le, Hoa V; Poole, Charles; Brookhart, M Alan; Schoenbach, Victor J; Beach, Kathleen J; Layton, J Bradley; Stürmer, Til
2013-11-19
The High-Dimensional Propensity Score (hd-PS) algorithm can select and adjust for baseline confounders of treatment-outcome associations in pharmacoepidemiologic studies that use healthcare claims data. How hd-PS performance is affected by aggregating medications or medical diagnoses has not been assessed. We evaluated the effects of aggregating medications or diagnoses on hd-PS performance in an empirical example using resampled cohorts with small sample size, rare outcome incidence, or low exposure prevalence. In a cohort study comparing the risk of upper gastrointestinal complications in celecoxib or traditional NSAIDs (diclofenac, ibuprofen) initiators with rheumatoid arthritis and osteoarthritis, we (1) aggregated medications and International Classification of Diseases-9 (ICD-9) diagnoses into hierarchies of the Anatomical Therapeutic Chemical classification (ATC) and the Clinical Classification Software (CCS), respectively, and (2) sampled the full cohort using techniques validated by simulations to create 9,600 samples to compare 16 aggregation scenarios across 50% and 20% samples with varying outcome incidence and exposure prevalence. We applied hd-PS to estimate relative risks (RR) using 5 dimensions, predefined confounders, ≤ 500 hd-PS covariates, and propensity score deciles. For each scenario, we calculated: (1) the geometric mean RR; (2) the difference between the scenario mean ln(RR) and the ln(RR) from published randomized controlled trials (RCT); and (3) the proportional difference in the degree of estimated confounding between that scenario and the base scenario (no aggregation). Compared with the base scenario, aggregations of medications into ATC level 4 alone or in combination with aggregation of diagnoses into CCS level 1 improved the hd-PS confounding adjustment in most scenarios, reducing residual confounding compared with the RCT findings by up to 19%. Aggregation of codes using hierarchical coding systems may improve the performance of
Collins, Rebecca L; Martino, Steven C; Elliott, Marc N
2011-03-01
Longitudinal research has demonstrated a link between exposure to sexual content in media and subsequent changes in adolescent sexual behavior, including initiation of intercourse and various noncoital sexual activities. Based on a reanalysis of one of the data sets involved, Steinberg and Monahan (2011) have challenged these findings. However, propensity score approaches-especially the version of this method used by Steinberg and Monahan, which lacks covariates-do not necessarily result in more accurate estimates of treatment effects than does the regression with covariates approach employed by prior research. There are also a number of problems with the specific set of analyses presented by Steinberg and Monahan and the conclusion they draw from them. In contrast to Steinberg and Monahan's claim, there is substantial evidence of an association between sexual media exposure and adolescent sexual initiation. PsycINFO Database Record (c) 2011 APA, all rights reserved.
Lin, Steven H.; Wang, Lu; Myles, Bevan; Thall, Peter F.; Hofstetter, Wayne L.; Swisher, Stephen G.; Ajani, Jaffer A.; Cox, James D.; Komaki, Ritsuko; Liao, Zhongxing
2014-01-01
Purpose Although 3DCRT is the worldwide standard for the treatment of esophageal cancers, IMRT improves dose conformality and reduces radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared to 3DCRT. Methods and Materials Analysis was performed on 676 nonrandomized patients (3DCRT=413, IMRT=263) with stage Ib-IVa (AJCC 2002) esophageal cancers treated with chemoradiation at a single institution from 1998–2008. An inverse probability of treatment weighting (IPW) and inclusion of propensity score (treatment probability) as a covariate were used to compare overall survival (OS) time, time to local failure, and time to distant metastasis, while accounting for effects of other clinically relevant covariates. Propensity scores were estimated using logistic regression. Results A fitted multivariate inverse probability weighted (IPW)-adjusted Cox model showed that OS time was significantly associated with several well-known prognostic factors, along with radiation modality (IMRT vs 3DCRT, HR=0.72, p<0.001). Compared to IMRT, 3DCRT patients had a significantly greater risk of dying (72.6% vs 52.9%, IPW log rank test: p<0.0001) and for local-regional recurrence (LRR) (p=0.0038). There was no difference in cancer-specific mortality (Gray’s test, p=0.86), or distant metastasis (p=0.99) between the two groups. An increased cumulative incidence of cardiac deaths was seen in the 3DCRT group (p=0.049), but most deaths were undocumented (5 year estimate: 11.7% in 3DCRT vs 5.4% in IMRT, Gray’s test, p=0.0029). Conclusions Overall survival, locoregional control, and non-cancer related deaths were significantly better for IMRT compared to 3DCRT. Although these results need confirmation, IMRT should be considered for the treatment of esophageal cancer. PMID:22867894
Borah, Bijan J; Moriarty, James P; Crown, William H; Doshi, Jalpa A
2014-01-01
Propensity score (PS) methods have proliferated in recent years in observational studies in general and in observational comparative effectiveness research (CER) in particular. PS methods are an important set of tools for estimating treatment effects in observational studies, enabling adjustment for measured confounders in an easy-to-understand and transparent way. This article demonstrates how PS methods have been used to address specific CER questions from 2001 through to 2012 by identifying six impactful studies from this period. This article also discusses areas for improvement, including data infrastructure, and a unified set of guidelines in terms of PS implementation and reporting, which will boost confidence in evidence generated through observational CER using PS methods.
Association of educational status with heart rate recovery: a population-based propensity analysis.
Shishehbor, Mehdi H; Baker, David W; Blackstone, Eugene H; Lauer, Michael S
2002-12-01
An abnormally attenuated heart rate recovery after exercise is a predictor of mortality that is thought to reflect decreased parasympathetic activity. Lower educational level may be associated with automatic imbalance. We sought to assess the association of educational level with heart rate recovery. Among 5246 healthy adults from a population-based cohort who underwent exercise testing, 874 (17%) did not graduate from high school, 1823 (35%) completed high school, and 2549 (49%) attended at least some college. An abnormal heart rate recovery was defined as a difference of =42 beats per minute between the peak heart rate and that after 2 minutes of recovery. Propensity scores were used to account for differences by educational status. An abnormal heart rate recovery was more common among adults who did not graduate from high school compared with those who attended at least some college (50% [440/874] vs. 28% [701/2549]; odds ratio [OR]: 2.7; 95% confidence interval [CI]: 2.3 to 3.1; P <0.001). After using propensity scores, lower educational status remained associated with an abnormal heart rate recovery (OR = 1.9; 95% CI: 1.6 to 2.4; P <0.001). During 12-years of follow-up, there were 327 deaths. Poor educational status was associated with greater mortality (9% [80/874] vs. 6% [247/4372]; unadjusted hazard ratio [HR] = 1.9; 95% CI: 1.4 to 2.5; P <0.001). However, after accounting for age, sex, and heart rate recovery, educational status was a weaker predictor (HR = 1.3; 95% CI: 1.0 to 1.7). Educational status is independently associated with an abnormal heart rate recovery.
D'Ascenzo, Fabrizio; Benedetto, Umberto; Bianco, Matteo; Conrotto, Federico; Moretti, Claudio; D'Onofrio, Augusto; Agrifoglio, Marco; Colombo, Antonio; Ribichini, Flavio; Tarantini, Giuseppe; D'Amico, Maurizio; Salizzoni, Stefano; Rinaldi, Mauro
2017-12-08
The safety and efficacy of single vs. dual antiplatelet therapy (DAPT) in patients undergoing TAVI remain to be addressed. The aim of our study was to evaluate the usefulness of a DAPT compared to a single platelet therapy in patients undergoing TAVI with a balloon-expandable prosthesis. All consecutive patients enrolled in the ITER registry were included. Patients undergoing TAVI discharged with aspirin alone were compared to those taking DAPT before and after selection using propensity score with matching. Subgroup analysis was performed for those on OAT. Prosthetic heart valve dysfunction at follow-up was the primary endpoint, whereas all-cause death, cardiovascular death, bleedings, vascular complications and cerebrovascular accidents were the secondary ones. From 1,364 patients, after propensity score with matching, 605 were selected for each group (aspirin alone vs. DAPT). At 30 days, rates of VARC mortality were lower in patients with aspirin alone (1.5% vs. 4.1%, p=0.003), mainly driven by a reduction of major vascular complications (5.3% vs. 10.7%, p<0.001) and of major bleedings (6.6% vs. 11.5%, p<0.001), without a difference in prosthetic heart valve dysfunction after 45±14 months (2.8% vs. 3.0%, p=0.50). These results were confirmed on multivariable analysis. After TAVI with a balloon-expandable prosthesis, aspirin alone does not increase the risk of prosthetic valve dysfunction, and reduces the risk of periprocedural complications and of 30-day all-cause death.
Guller, Ulrich; Tarantino, Ignazio; Cerny, Thomas; Ulrich, Alexis; Schmied, Bruno M; Warschkow, Rene
2017-01-01
The objective of the present analysis was to assess whether small bowel gastrointestinal stromal tumor (GIST) is associated with worse cancer-specific survival (CSS) and overall survival (OS) compared with gastric GIST on a population-based level. Data on patients aged 18 years or older with histologically proven GIST was extracted from the SEER database from 1998 to 2011. OS and CSS for small bowel GIST were compared with OS and CSS for gastric GIST by application of adjusted and unadjusted Cox regression analyses and propensity score analyses. GIST were located in the stomach (n = 3011, 59 %), duodenum (n = 313, 6 %), jejunum/ileum (n = 1288, 25 %), colon (n = 139, 3 %), rectum (n = 172, 3 %), and extraviscerally (n = 173, 3 %). OS and CSS of patients with GIST in the duodenum [OS, HR 0.95, 95 % confidence interval (CI) 0.76-1.19; CSS, HR 0.99, 95 % CI 0.76-1.29] and in the jejunum/ileum (OS, HR 0.97, 95 % CI 0.85-1.10; CSS, HR = 0.95, 95 % CI 0.81-1.10) were similar to those of patients with gastric GIST in multivariate analyses. Conversely, OS and CSS of patients with GIST in the colon (OS, HR 1.40; 95 % CI 1.07-1.83; CSS, HR 1.89, 95 % CI 1.41-2.54) and in an extravisceral location (OS, HR 1.42, 95 % CI 1.14-1.77; CSS, HR = 1.43, 95 % CI 1.11-1.84) were significantly worse than those of patients with gastric GIST. Contrary to common belief, OS and CSS of patients with small bowel GIST are not statistically different from those of patients with gastric GIST when adjustment is made for confounding variables on a population-based level. The prognosis of patients with nongastric GIST is worse because of a colonic and extravisceral GIST location. These findings have implications regarding adjuvant treatment of GIST patients. Hence, the dogma that small bowel GIST patients have worse prognosis than gastric GIST patients and therefore should receive adjuvant treatment to a greater extent must be revisited.
Steeg, S; Emsley, R; Carr, M; Cooper, J; Kapur, N
2018-01-01
The care received by people presenting to hospital following self-harm varies and it is unclear how different types of treatment affect risk of further self-harm. Observational cohort data from the Manchester Self-Harm Project, UK, included 16 456 individuals presenting to an Emergency Department with self-harm between 2003 and 2011. Individuals were followed up for 12 months. We also used data from a smaller cohort of individuals presenting to 31 hospitals in England during a 3-month period in 2010/2011, followed up for 6 months. Propensity score (PS) methods were used to address observed confounding. Missing data were imputed using multiple imputation. Following PS stratification, those who received a psychosocial assessment had a lower risk of repeat hospital attendance for self-harm than those who were not assessed [RR 0.87, 95% confidence interval (CI) 0.80-0.95]. The risk was reduced most among people less likely to be assessed. Following PS matching, we found no associations between risks of repeat self-harm and admission to a medical bed, referral to outpatient psychiatry or admission to a psychiatric bed. We did not find a relationship between psychosocial assessment and repeat self-harm in the 31 centre cohort. This study shows the potential value of using novel statistical techniques in large mental health datasets to estimate treatment effects. We found that specialist psychosocial assessment may reduce the risk of repeat self-harm. This type of routine care should be provided for all individuals who present to hospital after self-harm, regardless of perceived risk.
Gupta, Punkaj; Rettiganti, Mallikarjuna
2015-11-01
To evaluate the outcomes among critically ill young children with Down syndrome using propensity score matching from a national database. Patients in the age group from one day through 24 months admitted to an intensive care unit during their hospital stay at a Pediatric Health Information System (PHIS)-participating hospital (2004-2013) were included. Of the 293,697 patients who qualified for inclusion, 12,282 (4%) were classified in the Down syndrome group. Using propensity score matching, 10,477 patients with Down syndrome were matched one to one to patients without Down syndrome. Prior to matching, the mortality was significantly lower among the patients with Down syndrome (with vs. without Down syndrome, odds ratio (OR), 0.74; 95% confidence interval (CI), 0.69-0.79; p < 0.001). After matching, the mortality was similar in both groups (OR, 0.96; 95% CI, 0.87-1.07; p = 0.51). The mortality risk increased among the Down syndrome patients with increasing hospital length of stay (LOS). In this large, contemporary cohort, Down syndrome did not confer a significantly higher mortality risk among children with critical illness. However, children with Down syndrome followed a time-dependent, differential mortality risk with increased risk noted in relation to increasing hospital LOS. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.
Preventza, Ourania; Price, Matt D; Spiliotopoulos, Konstantinos; Amarasekara, Hiruni S; Cornwell, Lorraine D; Omer, Shuab; de la Cruz, Kim I; Zhang, Qianzi; Green, Susan Y; LeMaire, Scott A; Rosengart, Todd K; Coselli, Joseph S
2018-05-01
The preferred arterial cannulation site for elective proximal aortic procedures requiring circulatory arrest varies, and different sites have been tried. We evaluated the relationships between arterial cannulation site and adverse outcomes, including stroke, in patients undergoing elective aortic arch surgery. We reviewed the records of 938 patients who underwent elective hemiarch or total arch surgery with circulatory arrest between 2006 and 2016. Five cannulation sites were used: the right axillary (n = 515; 54.9%), innominate (n = 376; 40.1%), and right common carotid arteries (n = 15; 1.6%), each with a side graft; the ascending aorta (n = 19; 2.0%); and the femoral artery (n = 13; 1.4%). Multivariable logistic regression analysis was used to model the effects of cannulation site on adverse outcomes for the entire cohort and for a subcohort of 891 patients who underwent innominate or axillary artery cannulation. Propensity-matching yielded 564 patients (282 pairs) from the right axillary and innominate artery groups. For the entire cohort, mortality, stroke, and composite adverse outcome (operative death or persistent stroke or renal failure at hospital discharge) rates were 7.0%, 4.1%, and 9.8%. In the multivariable analysis of the axillary/innominate subcohort, cannulation site did not independently predict operative mortality, persistent stroke, or composite adverse event. These results were confirmed with the propensity-matched analysis, where both axillary and innominate artery cannulation provided equivalent composite adverse event rates, operative death rates, and overall stroke rates. During elective arch surgery, right axillary artery cannulation and innominate artery cannulation (both via a side graft) produce excellent results and can be used interchangeably. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
Jeffery, Diana D; Mattiko, Mark
2016-01-01
Numerous studies document higher substance use among military men after deployment; similar studies focused on military women are limited. This study examines alcohol use of active duty women and deployment factors, social/environmental/attitudinal factors, and psychological/intrapersonal factors. Secondary data analysis of the 2011 Survey of Health-Related Behavior of active duty military personnel was conducted using bivariate statistics and multiple regression analyses with Alcohol Use Disorders Identification Test scores as the dependent variable. Nearly 94% had low risk for alcohol use disorders. Length of combat experience and extent of combat exposure were unrelated to Alcohol Use Disorders Identification Test scores; noncombat deployment was unrelated after controlling for marital status, age of first drink, pay grade, and branch of service. Significant motivators (p < 0.001) for drinking were "like/enjoy drinking," "drink to cheer up," "drink to forget problems," and significant deterrents were "cost of alcohol" and "fear of upsetting family/friends if used alcohol." Anger propensity, risk propensity, lifetime prevalence of suicidal ideation, and depressed mood were significant predictors in the regression model after controlling for covariates. Findings suggest that some active duty women use alcohol to cope with adverse emotional states, whereas others use alcohol consistent with propensity for high-risk behaviors. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.
Ranganathan, Anjana; Dougherty, Meredith; Waite, David
2013-01-01
Abstract Objective This study examined the impact of palliative home nursing care on rates of hospital 30-day readmissions. Methods The electronic health record based retrospective cohort study was performed within home care and palliative home care programs. Participants were home care patients discharged from one of three urban teaching hospitals. Outcome measures were propensity score matched rates of hospital readmissions within 30 days of hospital discharge. Results Of 406 palliative home care patients, matches were identified for 392 (96%). Of 15,709 home care patients, 890 were used at least once as a match for palliative care patients, for a total final sample of 1282. Using the matched sample we calculated the average treatment effect for treated patients. In this sample, palliative care patients had a 30-day readmission probability of 9.1% compared to a probability of 17.4% in the home care group (mean ATT: 8.3%; 95% confidence interval [CI] 8.0%–8.6%). This effect persisted after adjustment for visit frequency. Conclusions Palliative home care may offer benefits to health systems by allowing patients to remain at home and thereby avoiding 30-day rehospitalizations. PMID:24007348
Laing, R W; Scalera, I; Isaac, J; Mergental, H; Mirza, D F; Hodson, J; Wilkin, R J W; Perera, M T P R; Muiesan, P
2016-06-01
The use of livers from donation after circulatory death (DCD) is increasing, but concerns exist regarding outcomes following use of grafts from "marginal" donors. To compare outcomes in transplants using DCD and donation after brain death (DBD), propensity score matching was performed for 973 patients with chronic liver disease and/or malignancy who underwent primary whole-liver transplant between 2004 and 2014 at University Hospitals Birmingham NHS Foundation Trust. Primary end points were overall graft and patient survival. Secondary end points included postoperative, biliary and vascular complications. Over 10 years, 234 transplants were carried out using DCD grafts. Of the 187 matched DCDs, 82.9% were classified as marginal per British Transplantation Society guidelines. Kaplan-Meier analysis of graft and patient survival found no significant differences for either outcome between the paired DCD and DBD patients (p = 0.162 and p = 0.519, respectively). Aspartate aminotransferase was significantly higher in DCD recipients until 48 h after transplant (p < 0.001). The incidences of acute kidney injury and ischemic cholangiopathy were greater in DCD recipients (32.6% vs. 15% [p < 0.001] and 9.1% vs. 1.1% [p < 0.001], respectively). With appropriate recipient selection, the use of DCDs, including those deemed marginal, can be safe and can produce outcomes comparable to those seen using DBD grafts in similar recipients. © Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.
Pham, Clarabelle T; Gibb, Catherine L; Mittinty, Murthy N; Fitridge, Robert A; Marshall, Villis R; Karnon, Jonathan D
2016-10-01
A physician-led clinic for the preoperative optimization and management of high-risk surgical patients was implemented in a South Australian public hospital in 2008. This study aimed to estimate the costs and effects of the clinic using a mixed retrospective and prospective observational study design. Alternative propensity score estimation methods were applied to retrospective routinely collected administrative and clinical data, using weighted and matched cohorts. Supplementary survey-based prospective data were collected to inform the analysis of the retrospective data and reduce potential unmeasured confounding. Using weighted cohorts, clinic patients had a significantly longer mean length of stay and higher mean cost. With the matched cohorts, reducing the calliper width resulted in a shorter mean length of stay in the clinic group, but the costs remained significantly higher. The prospective data indicated potential unmeasured confounding in all analyses other than in the most tightly matched cohorts. The application of alternative propensity-based approaches to a large sample of retrospective data, supplemented with a smaller sample of prospective data, informed a pragmatic approach to reducing potential observed and unmeasured confounding in an evaluation of a physician-led preoperative clinic. The need to generate tightly matched cohorts to reduce the potential for unmeasured confounding indicates that significant uncertainty remains around the effects of the clinic. This study illustrates the value of mixed retrospective and prospective observational study designs but also underlines the need to prospectively plan for the evaluation of costs and effects alongside the implementation of significant service innovations. © 2016 John Wiley & Sons, Ltd.
De Ridder, Karin A A; Pape, Kristine; Cuypers, Koenraad; Johnsen, Roar; Holmen, Turid Lingaas; Westin, Steinar; Bjørngaard, Johan Håkon
2013-10-09
High school dropout and long-term sickness absence/disability pension in young adulthood are strongly associated. We investigated whether common risk factors in adolescence may confound this association. Data from 6612 school-attending adolescents (13-20 years old) participating in the Norwegian Young-HUNT1 Survey (1995-1997) was linked to long-term sickness absence or disability pension from age 24-29 years old, recorded in the Norwegian Labour and Welfare Organisation registers (1998-2008). We used logistic regression to estimate risk differences of sickness or disability for school dropouts versus completers, adjusting for health, health-related behaviours, psychosocial factors, school problems, and parental socioeconomic position. In addition, we stratified the regression models of sickness and disability following dropout across the quintiles of the propensity score for high school dropout. The crude absolute risk difference for long-term sickness or disability for a school dropout compared to a completer was 0.21% or 21% points (95% confidence interval (CI), 17 to 24). The adjusted risk difference was reduced to 15% points (95% CI, 12 to 19). Overall, high school dropout increased the risk for sickness or disability regardless of the risk factor level present for high school dropout. High school dropouts have a strongly increased risk for sickness and disability in young adulthood across all quintiles of the propensity score for dropout, i.e. independent of own health, family and socioeconomic factors in adolescence. These findings reveal the importance of early prevention of dropout where possible, combined with increased attention to labour market integration and targeted support for those who fail to complete school.
Hafezi-Nejad, N; Guermazi, A; Roemer, F W; Eng, J; Zikria, B; Demehri, S
2016-04-01
To determine the association between the long-term use of analgesics and progression of osteoarthritis (OA) as evidenced by up to 3-years follow-up worsening of radiographic Kellgren-Lawrence (KL) grade and incidence of knee replacement (KR). Using nearest neighbor matching of the propensity scores with caliper in the Osteoarthritis Initiative (OAI) cohort, 173 index (Analgesic +) and 173 referent (Analgesic -) subjects were included. Analgesic + and - subjects had analgesics in all and none of their visits, respectively. Analgesic + and - subjects were balanced in their demographics, baseline, first, second and third year body mass index (BMI), Western Ontario and McMaster (WOMAC) total score, Physical and Mental health summary scales (SF-12), Physical Activity Scale for the Elderly (PASE) and Charleston Comorbidity Scale. Analgesic + and - subjects were also matched for baseline radiographic KL grade. Interval increase in the KL grade and incidence of KR were defined as the outcome. Included subjects had average 6.5 years of follow-up. By the third year, 44 subjects had an interval increase in the KL grade; 29 in Analgesic + and 15 among Analgesic - subjects (P = 0.024). By the eighth-year, 41 subjects had their first KR; 29 in Analgesic + and 12 among Analgesic - subjects (P = 0.005). Hazard Ratio (HR) of OA progression and KR for Analgesic + subjects was 1.91 (1.02-3.57) and 2.57 (1.31-5.04), respectively. Long-term use of analgesics may be associated with radiographic progression of knee OA and increased risk of future KR. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
Jaeger, Déborah; Dumas, Florence; Escutnaire, Josephine; Sadoune, Sonia; Lauvray, Adrien; Elkhoury, Carlos; Bassand, Adrien; Girerd, Nicolas; Gueugniaud, Pierre Yves; Tazarourte, Karim; Hubert, Hervé; Cariou, Alain; Chouihed, Tahar
2018-05-01
The survival rate of out-of-hospital cardiac arrest (OHCA) remains extremely low, generally under 10%. Post-resuscitation care, and particularly early coronary reperfusion, may improve this outcome. The main objective of the present study was to determine whether patients with immediate coronary angiography at hospital admission (CAA) had a better outcome than patients without immediate CAA. This cohort analysis study was based on data extracted from the French National Cardiac Arrest registry (RéAC). To control for attribution bias, patients were matched using a propensity score, which included age clusters, low flow and no flow delays, initial rhythm and bystander cardiopulmonary resuscitation (CPR). The main endpoint was survival at day 30 (D30). Secondary endpoint was neurological recovery of survivors assessed by the Cerebral Performance Category (CPC) scale, with CPC 1 and 2 at D30 considered as a favorable outcome. From July 1st, 2011 to October 1st, 2016, 63394 OHCA were registered in the database, of which 39444 were of an unknown or suspected cardiac origin. After on-site resuscitation by a mobile medical team, 7584 patients were transported to a hospital facility. Among these patients, 4046 were retained in the analysis after matching for the aforementioned factors and constituted into 2 groups: immediate coronary angiography (iCAA) group (n = 2023) and non-immediate coronary angiography (niCAA) group (n = 2023). The survival rate at D30 after matching was 43.3% in the iCAA group versus 34.5% in the niCAA group (OD = 0.66 [0.58; 0.75], p < 0.001). In the iCAA group, (n = 707) 36% of the patients at D30 were CPC 1-2 comparatively to (n = 539) 27.3% in the niCAA group (p < 0.01). Both the survival and proportion of patients with favorable neurological recovery were significantly higher in patients who underwent an immediate coronary angiography after a resuscitated OHCA. These observational results warrant further exploration
Bonora, Antonio; Turcato, Gianni; Franchi, Elena; Taioli, Gabriele; Dilda, Alice; Zerman, Germana; Maccagnani, Antonio; Pistorelli, Claudio; Olivieri, Oliviero
2017-09-01
The acute management of recent-onset (<48 h) atrial fibrillation (AF) is still debated. Aim of our study was to compare efficacy and safety of intravenously administered class IC antidysrhythmic agents vs amiodarone in a propensity score matched series of patients acutely treated for AF in the emergency department. During a 3-year period, we retrospectively evaluated all episodes of recent-onset (<48 h) AF pharmacologically treated for sinus rhythm restoration in the emergency department. By means of a propensity score matching considering the main statistically different covariates, we selected two accurately matched treatment groups. We analysed the differences between amiodarone and class IC group in terms of efficacy and safety that is conversion to sinus rhythm rates within 12 and 48 h after starting treatment, time to conversion, and adverse drug effects. An overall number of 817 episodes of recent-onset AF were collected (amiodarone group = 406, class IC group = 411). After matching, we obtained 358 episodes equally divided (amiodarone group = 179 and class IC group = 179). Conversion rates within 12 h were 139 (53.1 %) in amiodarone group and 95 (72.6 %) in class IC group (p < 0.05). Median time for cardioversion was 420 min (331.6-508.3 CI 95 %) in amiodarone and 55 min (44.9-65.1 CI 95 %) in class IC group (p < 0.05). The incidence of adverse events in both groups was very low and equally distributed (p = ns). Intravenously administration of class IC agents, when compared with amiodarone, proved to be more rapid and effective, and equally safe in the acute management of recent-onset AF.
Stürmer, Til; Wyss, Richard; Glynn, Robert J.; Brookhart, M. Alan
2014-01-01
Treatment effects, especially when comparing two or more therapeutic alternatives as in comparative effectiveness research, are likely to be heterogeneous across age, gender, co-morbidities, and co-medications. Propensity scores (PSs), an alternative to multivariable outcome models to control for measured confounding, have specific advantages in the presence of heterogeneous treatment effects. Implementing PSs using matching or weighting allows us to estimate different overall treatment effects in differently defined populations. Heterogeneous treatment effects can also be due to unmeasured confounding concentrated in those treated contrary to prediction. Sensitivity analyses based on PSs can help to assess such unmeasured confounding. PSs should be considered a primary or secondary analytic strategy in non-experimental medical research, including pharmacoepidemiology and non-experimental comparative effectiveness research. PMID:24520806
Tang, Yuqing; Zhang, Xiaopeng; Yang, Chunyan; Yang, Lianping; Wang, Hongtao; Zhang, Xinping
2013-05-21
The problem posed by therapeutic injection is a clinical practice issue that influences health care quality and patient safety. Although sufficient government subsidy was one of the 12 key interventions to promote rational drug use initiated by WHO (World Health Organization), limited information is available about the association between government subsidy and injection use in primary health care institutions. In 2009, National Essential Medicines System (NEMS) was implemented in China. The subsidy policy plays an important role in maintaining primary health care institutions. This study explores the impact of government subsidies on the injection use in primary health care institutions in China. 126 primary health institutions were included in this study. Institutions were divided into two groups (intervention and control groups) according to the median GS (General subsidy per personnel). Propensity score matching (PSM) was used to minimize the observed covariate differences in the characteristics of the primary institutions between the two groups. Kappa score was calculated to determine the consistency between the groups. Paired chi-square test and Relative Risk (RR) were calculated to compare the differences in injection use between the groups. Among all the investigated prescriptions, the overall percent of people who received an injection prescribed was 36.96% (n = 12600). PSM showed no significant covariate difference among the 34 groups obtained through this analysis. Kappa score (k = -0.082, p = 0.558) indicated an inconsistency between groups and paired chi-square test revealed a significant difference (p < 0.05) in injection use between the two groups. Relative Risk = 0.679 (95%CI [0.485, 0.950]) indicate that high General subsidy per personnel is a protective factor for primary health care institutions to prescribe injections properly. The intervention group obtained a higher possibility of using injection properly. The overall effect of government
Renehan, Andrew G; Malcomson, Lee; Emsley, Richard; Gollins, Simon; Maw, Andrew; Myint, Arthur Sun; Rooney, Paul S; Susnerwala, Shabbir; Blower, Anthony; Saunders, Mark P; Wilson, Malcolm S; Scott, Nigel; O'Dwyer, Sarah T
2016-02-01
Induction of a clinical complete response with chemoradiotherapy, followed by observation via a watch-and-wait approach, has emerged as a management option for patients with rectal cancer. We aimed to address the shortage of evidence regarding the safety of the watch-and-wait approach by comparing oncological outcomes between patients managed by watch and wait who achieved a clinical complete response and those who had surgical resection (standard care). Oncological Outcomes after Clinical Complete Response in Patients with Rectal Cancer (OnCoRe) was a propensity-score matched cohort analysis study, that included patients of all ages diagnosed with rectal adenocarcinoma without distant metastases who had received preoperative chemoradiotherapy (45 Gy in 25 daily fractions with concurrent fluoropyrimidine-based chemotherapy) at a tertiary cancer centre in Manchester, UK, between Jan 14, 2011, and April 15, 2013. Patients who had a clinical complete response were offered management with the watch-and-wait approach, and patients who did not have a complete clinical response were offered surgical resection if eligible. We also included patients with a clinical complete response managed by watch and wait between March 10, 2005, and Jan 21, 2015, across three neighbouring UK regional cancer centres, whose details were obtained through a registry. For comparative analyses, we derived one-to-one paired cohorts of watch and wait versus surgical resection using propensity-score matching (including T stage, age, and performance status). The primary endpoint was non-regrowth disease-free survival from the date that chemoradiotherapy was started, and secondary endpoints were overall survival, and colostomy-free survival. We used a conservative p value of less than 0·01 to indicate statistical significance in the comparative analyses. 259 patients were included in our Manchester tertiary cancer centre cohort, 228 of whom underwent surgical resection at referring hospitals and
Gelsomino, Sandro; Lorusso, Roberto; Romagnoli, Stefano; Bevilacqua, Sergio; De Cicco, Giuseppe; Billè, Giuseppe; Stefàno, Pierluigi; Gensini, Gian Franco
2008-01-01
Recombinant activated factor VII (rFVIIa) has been increasingly used to stop life-threatening bleeding following cardiac operations. Nonetheless, the issue of dosing, given the expense and potential for thrombotic complications, is still of major concern. We report our experience with small-dose rFVIIa in patients with refractory bleeding after cardiac surgery. From September 2005 to June 2007, 40 patients (mean age 70.1+/-9.2 years, 52.5 males) received a low dose of rFVIIa (median: 18 microg/kg, interquartile range: 9-16 microg/kg) for refractory bleeding after cardiac surgery. Forty propensity score-based greedy matched controls were compared to the study group. Low dose of rFVIIa significantly reduced the 24-h blood loss: 1610 ml [ 1285-1800 ml] versus 3171 ml [2725-3760 ml] in the study and control groups, respectively (p<0.001). Thus, hourly bleeding was 51.1 ml [34.7-65.4 ml] in patients receiving rFVIIa and 196.2 ml/h [142.1-202.9 ml] in controls (p<0.001). Furthermore, patients receiving rFVIIa showed a lower length of stay in the intensive care unit (p<0.001) and shorter mechanical ventilation time (p<0.001). In addition, the use of rFVIIa was associated with reduction of transfusion requirements of red blood cells, fresh frozen plasma and platelets (all, p<0.001). Finally, treated patients showed improved hemostasis with rapid normalization of coagulation variables (partial thromboplastin time, international normalized ratio, platelet count, p<0.001). In contrast, activated prothrombin time and fibrinogen did not differ between groups (p=ns). No thromboembolic-related event was detected in our cohort. In our experience low-dose rFVIIa was associated with reduced blood loss, improvement of coagulation variables and decreased need for transfusions. Our findings need to be confirmed by further larger studies.
Ohkura, Yu; Shindoh, Junichi; Ueno, Masaki; Iizuka, Toshiro; Haruta, Shusuke; Udagawa, Harushi
2018-05-01
To investigate the efficacy of postoperative scheduled intravenous acetaminophen to reduce the opioid use and enhance the recovery after esophagectomy. A propensity score-matched population was created using the 93 and 69 consecutive patients who underwent esophagectomy for esophageal cancer before and after the introduction of postoperative scheduled intravenous acetaminophen, and the short-term clinical outcomes were compared. Significant defervescence was demonstrated in the Acetaminophen group (A-group) compared with control group (C-group) during the perioperative period (p < 0.05), whereas no significant differences were observed in the postoperative inflammatory parameters. The incidence of postoperative complications was similar between the groups. The number of PCA pushes and the frequency of using other non-opioid analgesics were significantly smaller in the A-group than in the C-group (p < 0.05). Both daily and cumulative opioid uses were significantly smaller in the A-group than in the C-group (p < 0.05). The time to first flatus was significantly shorter in the A-group than in the C-group (p < 0.001). The day of first walking after surgery was significantly earlier in the A-group than in the C-group (1.0 versus 2.0 days, p = 0.003). The ICU stay (2.86 versus 3.61 days, p < 0.001) and the hospital stay (21.5 versus 26.0 days, p = 0.061) tended to be shorter in the A-group than in the C-group. Postoperative scheduled intravenous acetaminophen decreased the rate of opioid use without increasing the intensity of postoperative pain and may be a feasible new pain management option in the enhanced recovery after surgery protocol following esophagectomy.
Van Berkel, Megan A; Exline, Matthew C; Cape, Kari M; Ryder, Lindsay P; Phillips, Gary; Ali, Naeem A; Doepker, Bruce A
2017-04-01
This study compared the incidence of clinical hypotension between ketamine and etomidate within a 24 hour period following endotracheal intubation. This single-center, retrospective propensity-matched cohort study included septic patients admitted to our medical intensive care unit who received either etomidate or ketamine for intubation. Clinical hypotension was defined as any one of the following: mean arterial pressure (MAP) decrease >40% compared to baseline and MAP <70 mmHg, MAP <60 mmHg, initiation of a vasopressor, or increase to >30% of the initial vasopressor dose. Patients were matched based on propensity scores determined by demographics and baseline characteristics. A total of 384 (200 etomidate and 184 ketamine) patients were included for analysis with 230 patients (115 in each group) matched. Clinical hypotension was less prevalent in patients who received ketamine as compared to etomidate [51.3% vs. 73% (odds ratio=0.39, 95% confidence interval=0.22-0.67, P=.001]. The etomidate group experienced significantly lower MAPs at time periods 6.1-12 hours (65.1 mmHg vs. 69.3 mmHg, P=.01) and 12.1-24 hours (63.9 mmHg vs. 68.4 mmHg, P=.003). Ketamine was associated with a lower incidence of clinical hypotension within the 24 hour period following endotracheal intubation in septic patients. Copyright © 2016 Elsevier Inc. All rights reserved.
O'Connor, Seini; Jose, Paul E
2012-11-01
Extracurricular activities are important in many young people's lives and have been associated with positive academic, psychological, and social outcomes. However, most previous research has been limited to school-based activities in the North American context. This study expands existing literature by analyzing longitudinal data from more than 1,300 young Māori and European New Zealanders, using propensity score matching techniques to control for selection effects. Results suggest that youth participating in community-based activities experienced greater social support than nonparticipants. For Māori youth, participating in nonsports activities was associated with later benefits, while for New Zealand European youth, benefits were associated with sports activities. Participants of different ages reported different types of benefits. These findings highlight points of similarity and difference between New Zealand and North American youth and provide a better understanding of the positive impacts of community-based activities for young people.
Broström, Anders; Pakpour, A H; Ulander, Martin; Nilsen, Per
2018-05-18
To develop and validate a Swedish questionnaire to measure propensity for behaviour change regarding food habits, physical activity and weight reduction in patients with hypertension. Cross-sectional design. A total of 270 consecutive patients with hypertension diagnosed at 4 primary care centres in Sweden were included. The 6-item Swedish version of the Propensity to Achieve Healthy Lifestyle Scale (PAHLS) was developed to measure propensity for behaviour change regarding food habits, physical activity and weight reduction. The PAHLS (i.e., including 3 items for preparedness and 3 items for capacity) was developed by 3 multi-professional researchers inspired by the Transtheoretical Model of Behaviour Change in collaboration with clinically active nurses. Data were collected by questionnaires on food habits (i.e., the Food Frequency Questionnaire), physical activity (the International Physical Activity Questionnaire), propensity for a healthy lifestyle (the PHLQ), as well as during a clinical examination. Exploratory (EFA) and confirmatory factor analyses (CFA), as well as Rasch analysis, were used. Of the 270 patients (50% women), 27% scored low levels of physical activity on the International Physical Activity Questionnaire, and 34% of the patients were obese (body mass index ≥30 kg/m 2 ). The EFA (explaining 54% of the variance) showed unidimensionality for the PAHLS that was supported by both CFA and Rasch analyses. No floor and 1.9% ceiling effects were found. Multiple group CFA (an extension of structural equation modelling) showed that the PAHLS operated equivalently across both male and female patients. Internal consistency (Cronbach's alpha 0.83) and composite reliability (0.89) were good. The initial testing of PAHLS provided good validity and reliability scores to measure propensity for behaviour change in patients with hypertension. The PAHLS can be used by nurses as a tool to simplify shared decision making in relation to behavioural changes. This
Nock, M K; Dempsey, C L; Aliaga, P A; Brent, D A; Heeringa, S G; Kessler, R C; Stein, M B; Ursano, R J; Benedek, D
2017-11-01
The suicide rate has increased significantly among US Army soldiers over the past decade. Here we report the first results from a large psychological autopsy study using two control groups designed to reveal risk factors for suicide death among soldiers beyond known sociodemographic factors and the presence of suicide ideation. Informants were next-of-kin and Army supervisors for: 135 suicide cases, 137 control soldiers propensity-score-matched on known sociodemographic risk factors for suicide and Army history variables, and 118 control soldiers who reported suicide ideation in the past year. Results revealed that most (79.3%) soldiers who died by suicide have a prior mental disorder; mental disorders in the prior 30-days were especially strong risk factors for suicide death. Approximately half of suicide decedents tell someone that they are considering suicide. Virtually all of the risk factors identified in this study differed between suicide cases and propensity-score-matched controls, but did not significantly differ between suicide cases and suicide ideators. The most striking difference between suicides and ideators was the presence in the former of an internalizing disorder (especially depression) and multi-morbidity (i.e. 3+ disorders) in the past 30 days. Most soldiers who die by suicide have identifiable mental disorders shortly before their death and tell others about their suicidal thinking, suggesting that there are opportunities for prevention and intervention. However, few risk factors distinguish between suicide ideators and decedents, pointing to an important direction for future research.
Tsuchiya, Asuka; Tsutsumi, Yusuke; Yasunaga, Hideo
2016-11-29
Because of a lack of randomized controlled trials and the methodological weakness of currently available observational studies, the benefits of helicopter emergency medical services (HEMS) over ground emergency medical services (GEMS) for major trauma patients remain uncertain. The aim of this retrospective nationwide cohort study was to compare the mortality of adults with serious traumatic injuries who were transported by HEMS and GEMS, and to analyze the effects of HEMS in various subpopulations. Using the Japan Trauma Data Bank, we evaluated all adult patients who had an injury severity score ≥ 16 transported by HEMS or GEMS during the daytime between 2004 and 2014. We compared in-hospital mortality between patients transported by HEMS and GEMS using propensity score matching, inverse probability of treatment weighting and instrumental variable analyses to adjust for measured and unmeasured confounding factors. Eligible patients (n = 21,286) from 192 hospitals included 4128 transported by HEMS and 17,158 transported by GEMS. In the propensity score-matched model, there was a significant difference in the in-hospital mortality between HEMS and GEMS groups (22.2 vs. 24.5%, risk difference -2.3% [95% confidence interval, -4.2 to -0.5]; number needed to treat, 43 [95% confidence interval, 24 to 220]). The inverse probability of treatment weighting (20.8% vs. 23.9%; risk difference, -3.9% [95% confidence interval, -5.7 to -2.1]; number needed to treat, 26 [95% confidence interval, 17 to 48]) and instrumental variable analyses showed similar results (risk difference, -6.5% [95% confidence interval, -9.2 to -3.8]; number needed to treat, 15 [95% confidence interval, 11 to 27]). HEMS transport was significantly associated with lower in-hospital mortality after falls, compression injuries, severe chest injuries, extremity (including pelvic) injuries, and traumatic arrest on arrival to the emergency department. HEMS was associated with a significantly lower
Choi, HwaJung; Burgard, Sarah; Elo, Irma T; Heisler, Michele
2015-09-01
We assessed the potential contextual effect of income inequality on health by: 1) comparing individuals with similar socioeconomic status (SES) but who reside in counties with different levels of income inequality; and 2) examining whether the potential effect of county-level income inequality on health varies across SES groups. We used the Health and Retirement Study, a nationally representative study of Americans over the age of 50. Using propensity score matching, we selected SES-comparable individuals living in high-income inequality counties and in low-income inequality counties. We examined differences in self-rated overall health outcomes and in other specific physical/mental health outcomes between the two groups using logistic regression (n = 34,994) and imposing different sample restrictions based on residential duration in the area. We then used logistic regression with interactions to assess whether, and if so how, health outcomes differed among participants of different SES groups defined by wealth, income, and education. In bivariate analyses of the unmatched full sample, adults living in high-income inequality counties have worse health outcomes for most health measures. After propensity score matching, adults in high-income inequality counties had worse self-rated health status (AOR = 1.12; 95% CI 1.04-1.19) and were more likely to report diagnosed psychiatric problems (AOR = 1.08; 95% CI 0.99-1.19) than their matched counterparts in low-income inequality counties. These associations were stronger with longer-term residents in the area. Adverse health outcomes associated with living in high-income inequality counties were significant particularly for individuals in the 30(th) or greater percentiles of income/wealth distribution and those without a college education. In summary, after using more precise matching methods to compare individuals with similar characteristics and addressing measurement error by excluding more recently arrived county
Choi, HwaJung; Burgard, Sarah; Elo, Irma T.; Heisler, Michele
2015-01-01
We assessed the potential contextual effect of income inequality on health by: 1) comparing individuals with similar socioeconomic status (SES) but who reside in counties with different levels of income inequality; and 2) examining whether the potential effect of county-level income inequality on health varies across SES groups. We used the Health and Retirement Study, a nationally representative study of Americans over the age of 50. Using propensity score matching, we selected SES-comparable individuals living in high-income inequality counties and in low-income inequality counties. We examined differences in self-rated overall health outcomes and in other specific physical/mental health outcomes between the two groups using logistic regression (n=34,994) and imposing different sample restrictions based on residential duration in the area. We then used logistic regression with interactions to assess whether, and if so how, health outcomes differed among participants of different SES groups defined by wealth, income, and education. In bivariate analyses of the unmatched full sample, adults living in high-income inequality counties have worse health outcomes for most health measures. After propensity score matching, adults in high-income inequality counties had worse self-rated health status (AOR=1.12; 95% CI 1.04–1.19) and were more likely to report diagnosed psychiatric problems (AOR=1.08; 95% CI 0.99–1.19) than their matched counterparts in low-income inequality counties. These associations were stronger with longer-term residents in the area. Adverse health outcomes associated with living in high-income inequality counties were significant particularly for individuals in the 30th or greater percentiles of income/wealth distribution and those without a college education. In summary, after using more precise matching methods to compare individuals with similar characteristics and addressing measurement error by excluding more recently arrived county residents
Kumar, Shaji; Durie, Brian; Nahi, Hareth; Vij, Ravi; Dimopoulos, Meletios A; Kastritis, Efstathios; Terpos, Evangelos; Leleu, Xavier; Beksac, Meral; Goldschmidt, Hartmut; Hillengass, Jens; Su, Zhuo; Hutton, Brian; Cameron, Chris; Khan, Imran; Lam, Annette
2018-05-09
Daratumumab is a CD38-directed monoclonal antibody approved for treating multiple myeloma (MM). Propensity score matching (PSM) based on individual patient data (IPD) was conducted to compare overall survival (OS) and progression-free survival (PFS) for daratumumab versus real-world standard of care (SOC). IPD for patients with relapsed and refractory (RR) MM treated with daratumumab monotherapy were from the GEN501 and SIRIUS studies; IPD for patients treated with SOC were from an International Myeloma Working Group (IMWG) chart review of patients with RRMM. Prior to PSM, patients treated with daratumumab had significantly longer OS (median 20.1 vs. 10.1 months, hazard ratio [HR] = 0.51 [0.39-0.67]) and PFS (median 4.0 vs. 2.8 months, HR = 0.73 [0.58-0.92]) than patients treated with SOC therapies. After PSM, daratumumab maintained a significantly prolonged OS (19.9 vs. 9.2 months, HR = 0.44 [0.31-0.63]) and PFS (3.9 vs. 1.6 months, HR = 0.56 [0.42-0.74]) compared with SOC.
D'Ascenzo, Fabrizio; Iannaccone, Mario; Giordana, Francesca; Chieffo, Alaide; Connor, Stephen O; Napp, L Christian; Chandran, SujaySubash; de la Torre Hernández, José María; Chen, Shao-Liang; Varbella, Ferdinando; Omedè, Pierluigi; Taha, Salma; Meliga, Emanuele; Kawamoto, Hiroyoshi; Montefusco, Antonio; Chong, Mervyn; Garot, Philippe; Sin, Lin; Gasparetto, Valeria; Abdirashid, Mohamed; Cerrato, Enrico; Biondi-Zoccai, Giuseppe; Gaita, Fiorenzo; Escaned, Javier; Hiddick Smith, David; Lefèvre, Thierry; Colombo, Antonio; Sheiban, Imad; Moretti, Claudio
2016-05-15
There is uncertainty on which stenting approach confers the best long-term outlook for unprotected left main (ULM) bifurcation disease. This is a non-randomized, retrospective study including all consecutive patients with 50% stenosis of the left main involving at least 1 of the arteries stemming from the left main treated with drug-eluting stents (DES) in 9 European centers between 2002 and 2004. Patients were divided into two groups: those treated with provisional stentings vs. those treated with two stent strategy. The outcomes of interest were 10-year rates of target lesion revascularization (TLR), major adverse cardiac events (MACE), and their components (cardiovascular death, myocardial infarction [MI], or repeat revascularization), along with stent thrombosis (ST). A total of 285 patients were included, 178 (62.5%) in the provisional stenting group and 87 (37.5%) in the two stent group. After 10 years, no differences in TLR were found at unadjusted analysis (19% vs 25%, p>0.05) nor after propensity score matching (25% vs 28%, p>0.05). Similar rates of MACE (60% vs 66%, p>0.05), death (34% vs 43%, p>0.05), MI (9% vs 14%, p>0.05) and ST were also disclosed at propensity-based analysis. Even after 10 year follow-up, patients treated with provisional stenting on left main showed comparable rates of target lesion revascularization compared to two stent strategy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
The effect of bovine somatotropin on the cost of producing milk: Estimates using propensity scores.
Tauer, Loren W
2016-04-01
Annual farm-level data from New York dairy farms from the years 1994 through 2013 were used to estimate the cost effect from bovine somatotropin (bST) using propensity score matching. Cost of production was computed using the whole-farm method, which subtracts sales of crops and animals from total costs under the assumption that the cost of producing those products is equal to their sales values. For a farm to be included in this data set, milk receipts on that farm must have comprised 85% or more of total receipts, indicating that these farms are primarily milk producers. Farm use of bST, where 25% or more of the herd was treated, ranged annually from 25 to 47% of the farms. The average cost effect from the use of bST was estimated to be a reduction of $2.67 per 100 kg of milk produced in 2013 dollars, although annual cost reduction estimates ranged from statistical zero to $3.42 in nominal dollars. Nearest neighbor matching techniques generated a similar estimate of $2.78 in 2013 dollars. These cost reductions estimated from the use of bST represented a cost savings of 5.5% per kilogram of milk produced. Herd-level production increase per cow from the use of bST over 20 yr averaged 1,160 kg. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Boada, Aram; Tejera-Vaquerizo, Antonio; Ribero, Simone; Puig, Susana; Moreno-Ramírez, David; Descalzo-Gallego, Miguel A; Fierro, María T; Quaglino, Pietro; Carrera, Cristina; Malvehy, Josep; Vidal-Sicart, Sergi; Bennássar, Antoni; Rull, Ramón; Alos, Llucìa; Requena, Celia; Bolumar, Isidro; Traves, Víctor; Pla, Ángel; Fernández-Figueras, María T; Ferrándiz, Carlos; Pascual, Iciar; Manzano, José L; Sánchez-Lucas, Marina; Giménez-Xavier, Pol; Ferrandiz, Lara; Nagore, Eduardo
2018-02-01
The clinical value of sentinel lymph node (SLN) biopsy in thick melanoma patients (Breslow >4 mm) has not been sufficiently studied. The aim of the study is to evaluate whether SLN biopsy increases survival in patients with thick cutaneous melanoma, and, as a secondary objective, to investigate correlations between survival and lymph node status. We included 1,211 consecutive patients with thick melanomas (>4 mm) registered in the participating hospitals' melanoma databases between 1997 and 2015. Median follow-up was 40 months. Of these patients, 752 were matched into pairs by propensity scores based on sex, age, tumor location, histologic features of melanoma, year of diagnosis, hospital and adjuvant interferon therapy. The SLN biopsy vs. observation was associated with better DFS [adjusted hazard ratio (AHR), 0.74; 95% confidence interval (CI) 0.61-0.90); p = 0.002] and OS (AHR, 0.75; 95% CI, 0.60-0.94; p = 0.013) but not MSS (AHR, 0.84; 95% CI, 0.65-1.08; p = 0.165). SLN-negative patients had better 5- and 10-year MSS compared with SLN-positive patients (65.4 vs. 51.9% and 48.3 vs. 38.8%; p = 0.01, respectively). As a conclusion, SLN biopsy was associated with better DFS but not MSS in thick melanoma patients after adjustment for classic prognostic factors. SLN biopsy is useful for stratifying these patients into different prognostic groups. © 2017 UICC.
Fukuda, Tatsuma; Ohashi-Fukuda, Naoko; Kondo, Yutaka; Sera, Toshiki; Yahagi, Naoki
2017-06-01
The importance of respiratory care in cardiopulmonary resuscitation may vary depending on the cause of cardiac arrest. No previous study has investigated the effects of rescue breathing performed by a lay rescuer on the outcomes of patients with out-of-hospital cardiac arrest (OHCA) caused by intrinsic respiratory diseases. The aim of this study was to investigate whether rescue breathing performed by a lay rescuer is associated with outcomes after respiratory disease-related OHCA. In a nationwide, population-based, propensity score-matched study in Japan, among adult patients with OHCA caused by respiratory disease who received bystander cardiopulmonary resuscitation from January 1, 2005 to December 31, 2010, we compared patients with rescue breathing to those without rescue breathing. The primary outcome was neurologically favorable survival 1 month after OHCA. Of the eligible 14,781 patients, 4970 received rescue breathing from a lay rescuer and 9811 did not receive rescue breathing. In a propensity score-matched cohort (4897 vs. 4897 patients), the neurologically favorable survival rate was similar between patients with and without rescue breathing from a lay rescuer [0.9 vs. 0.7 %; OR 1.23 (95 % CI 0.79-1.93)]. Additionally, in subgroup analyses, rescue breathing was not associated with neurological outcome regardless of the type of rescuer [family member: adjusted OR 0.83 (95 % CI 0.39-1.70); or non-family member: adjusted OR 1.91 (95 % CI 0.79-5.35)]. Even among patients with OHCA caused by respiratory disease, rescue breathing performed by a lay rescuer was not associated with neurological outcomes, regardless of the type of lay rescuer.
Bhatia, Subir; Arora, Shilpkumar; Bhatia, Sravya M; Al-Hijji, Mohammed; Reddy, Yogesh N V; Patel, Parshva; Rihal, Charanjit S; Gersh, Bernard J; Deshmukh, Abhishek
2018-03-10
Chronic kidney disease (CKD) remains an independent predictor of cardiovascular morbidity and mortality. CKD complicates referral for percutaneous coronary intervention (PCI) in non-ST-segment-elevation myocardial infarction (NSTEMI) patients because of the risk for acute kidney injury and the need for dialysis, with American College of Cardiology/American Heart Association guidelines underscoring the limited data on these patients. Using the National Inpatient Sample to analyze hospitalizations in the United States from 2004 to 2014, we sought to assess PCI utilization and in-hospital outcomes in NSTEMI admissions with CKD. NSTEMI admissions were identified by International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) code 410.7. CKD admissions were identified by ICD-9-CM code 585. Propensity score-matched cohorts of patients with NSTEMI were matched for age, sex, comorbidities, race, median household income, primary payer status, and hospital characteristics. Of 4 488 795 hospitalizations for NSTEMI, 31% underwent PCI. Overall, 89% of admissions had no CKD. In addition, 32% of NSTEMI admissions with no CKD and 23%, 14%, and 22% with CKD stages 3, 4, and 5 underwent PCI, respectively. Hospitalized NSTEMI patients with CKD stages 4 and 5 had 41% and 20% less likelihood, respectively, of undergoing PCI compared with those with no CKD. Among hospitalized NSTEMI patients with no CKD or CKD stage 3, 4, or 5, PCI-treated groups had 63%, 57%, 39%, and 59% lower likelihood, respectively, of all-cause, in-hospital mortality compared with propensity score-matched medically managed groups. PCI use decreased among hospitalized NSTEMI patients as CKD severity increased, and all-cause, in-hospital mortality was greater for NSTEMI patients admitted with more severe CKD regardless of treatment strategy. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.
Lee, Sunyoung; Kang, Tae Wook; Cha, Dong Ik; Song, Kyoung Doo; Lee, Min Woo; Rhim, Hyunchul; Lim, Hyo Keun; Sinn, Dong Hyun; Kim, Jong Man; Kim, Kyunga
2018-07-01
The therapeutic outcomes of surgical resection (SR) or radiofrequency ablation (RFA) for perivascular hepatocellular carcinoma (HCC) have not been compared. The aim of this study was to compare SR with RFA as first-line treatment in patients with perivascular HCC and to evaluate the long-term outcomes of both therapies. This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Between January 2006 and December 2010, a total of 283 consecutive patients with small perivascular HCCs (≤3 cm, Barcelona Clinic Liver Cancer stage 0 or A) underwent SR (n = 182) or RFA (n = 101) as a first-line treatment. The progression-free survival (PFS) and overall survival (OS) rates were compared by propensity score matching. Subgroup analysis of these outcomes was conducted according to the type of hepatic vessels. The median follow-up was 7.8 years. Matching yielded 62 pairs of patients. In the two matched groups, the PFS rates at 5 and 10 years were 58.0% and 17.8%, respectively, in the SR group, and 25.4% and 14.1%, respectively, in the RFA group (p <0.001). The corresponding OS rates at 5 and 10 years were 93.5% and 91.9% in the SR group and 82.3% and 74.1% in the RFA group, respectively (p <0.001). In contrast to those in patients with perivenous HCCs, subgroup analysis indicated that extrahepatic recurrence and OS were significantly different according to the treatment modality in patients with periportal HCCs (p = 0.004 and p <0.001, respectively). In patients with small perivascular HCCs, SR provided better long-term tumor control and OS than RFA, particularly for periportal tumors. Surgical resection and radiofrequency ablation are both treatment options for perivascular hepatocellular carcinoma. We compared outcomes in patients treated with either method. Surgical resection provided better long-term tumor control and overall survival than radiofrequency ablation for patients with a
Bhavan, Kavita P; Brown, L Steven; Haley, Robert W
2015-12-01
powered for readmission but not for mortality. Clinical, sociodemographic, and outcome data were collected from the Parkland Hospital electronic medical records and the US census, constituting a historical prospective cohort study. We used multivariable logistic regression to develop a propensity score predicting S-OPAT versus H-OPAT group membership from covariates. We then estimated the effect of S-OPAT versus H-OPAT on the two outcomes using multivariable proportional hazards regression, controlling for selection bias and confounding with the propensity score and covariates. Of the 1,168 patients discharged to receive OPAT, 944 (81%) were managed in the S-OPAT program and 224 (19%) by H-OPAT services. In multivariable proportional hazards regression models controlling for confounding and selection bias, the 30-d readmission rate was 47% lower in the S-OPAT group (adjusted hazard ratio [aHR], 0.53; 95% CI 0.35-0.81; p = 0.003), and the 1-y mortality rate did not differ significantly between the groups (aHR, 0.86; 95% CI 0.37-2.00; p = 0.73). The S-OPAT program shifted a median 26 d of inpatient infusion per patient to the outpatient setting, avoiding 27,666 inpatient days. The main limitation of this observational study-the potential bias from the difference in healthcare funding status of the groups-was addressed by propensity score modeling. S-OPAT was associated with similar or better clinical outcomes than H-OPAT. S-OPAT may be an acceptable model of treatment for uninsured, medically stable patients to complete extended courses of IV antimicrobials at home.
Fu, Michael C; D'Ambrosia, Christopher; McLawhorn, Alexander S; Schairer, William W; Padgett, Douglas E; Cross, Michael B
2016-11-01
Obesity is frequently associated with complications after total hip arthroplasty (THA) and is often concomitant with malnutrition. The purpose of this study was to investigate the independent morbidity risk of malnutrition relative to obesity. The National Surgical Quality Improvement Program from 2005 to 2013 was queried for elective primary THA cases. Malnutrition was defined as albumin <3.5 g/dL. Propensity scores for having preoperative albumin data were determined from demographics, body mass index, and overall comorbidity burden. Patients were classified as nonobese (body mass index 18.5-29.9), obese I (30-34.9), obese II (35-39.9), or obese III (≥40). Complications were compared across nutritional and obesity classes. Multivariable propensity-adjusted logistic regressions were used to examine associations between obesity and malnutrition with 30-day outcomes. A total of 40,653 THA cases were identified, of which 20,210 (49.7%) had preoperative albumin measurements. Propensity score adjustment successfully reduced potential selection bias, with P > .05 for differences between those with and without albumin data. Malnutrition incidence increased from 2.8% in obese I to 5.7% in obese III patients. With multivariable propensity-adjusted logistic regression, malnutrition was a more robust predictor than any obesity class for any postoperative complication(s) (odds ratio [OR] 1.61, 95% confidence interval [CI] 1.25-2.08), major complications (OR 1.63, 95% CI 1.21-2.19), respiratory complications (OR 2.35, 95% CI 1.27-4.37), blood transfusions (OR 1.71, 95% CI 1.44-2.03), and extended length of stay (OR 1.35, 95% CI 1.14-1.59). Malnutrition incidence increased significantly from obese I to obese III patients and was a stronger and more consistent predictor than obesity of complications after THA. Copyright © 2016 Elsevier Inc. All rights reserved.
Dahabreh, Issa J.; Sheldrick, Radley C.; Paulus, Jessica K.; Chung, Mei; Varvarigou, Vasileia; Jafri, Haseeb; Rassen, Jeremy A.; Trikalinos, Thomas A.; Kitsios, Georgios D.
2012-01-01
Aims Randomized controlled trials (RCTs) are the gold standard for assessing the efficacy of therapeutic interventions because randomization protects from biases inherent in observational studies. Propensity score (PS) methods, proposed as a potential solution to confounding of the treatment–outcome association, are widely used in observational studies of therapeutic interventions for acute coronary syndromes (ACS). We aimed to systematically assess agreement between observational studies using PS methods and RCTs on therapeutic interventions for ACS. Methods and results We searched for observational studies of interventions for ACS that used PS methods to estimate treatment effects on short- or long-term mortality. Using a standardized algorithm, we matched observational studies to RCTs based on patients’ characteristics, interventions, and outcomes (‘topics’), and we compared estimates of treatment effect between the two designs. When multiple observational studies or RCTs were identified for the same topic, we performed a meta-analysis and used the summary relative risk for comparisons. We matched 21 observational studies investigating 17 distinct clinical topics to 63 RCTs (median = 3 RCTs per observational study) for short-term (7 topics) and long-term (10 topics) mortality. Estimates from PS analyses differed statistically significantly from randomized evidence in two instances; however, observational studies reported more extreme beneficial treatment effects compared with RCTs in 13 of 17 instances (P = 0.049). Sensitivity analyses limited to large RCTs, and using alternative meta-analysis models yielded similar results. Conclusion For the treatment of ACS, observational studies using PS methods produce treatment effect estimates that are of more extreme magnitude compared with those from RCTs, although the differences are rarely statistically significant. PMID:22711757
Ke, Yang; Zhong, Jianhong; Guo, Zhe; Liang, Yongrong; Li, Lequn; Xiang, Bangde
2014-03-18
To compare the long-term survival of patients with Barcelona Clinic Liver Cancer (BCLC) stage B hepatocellular carcinoma (HCC) undergoing either liver resection or transarterial chemoembolization (TACE) after propensity score matching (PSM). One hundred sixty-seven and 70 BCLC-B HCC patients undergoing liver resection and TACE were retrospectively collected. PSM function of SPSS software was conducted to reduce confounding bias between the groups. And then survival analysis was performed for the matched data. Fifty-three pairs of patients were successfully matched. And then survival analysis showed that the median survival periods and their 95% confidence intervals were 35.0 (26.3-43.7)months in the liver resection group versus 20.0(15.0-25.0) months in the TACE group. The 1, 3, 5 and 7-year survival rates were 91.0%, 49.0%, 30.0% and 17.0% in the liver resection group versus 73.0%, 25.0%, 8.0% and 5.0% respectively in the TACE group (P = 0.001). Cox regression analysis revealed that TACE, total bilirubin ≥ 34.2 µmol/L, alpha fetoprotein ≥ 400 ng/ml and tumor number ≥ 3 were independent risk factors of survival (hazard ratio >1, P < 0.05). The balance of covariates may be achieved through PSM. And for patients with BCLC-B HCC, liver resection provides better long-term overall survival than TACE.
Grube, Maike Miriam; von der Lippe, Elena; Schlaud, Martin; Brettschneider, Anna-Kristin
2015-01-01
Current studies suggest that the beneficial effect of breastfeeding on overweight and obesity may have been largely overestimated. We examined the relationship between >4 months of full breastfeeding and overweight/obesity in children living in Germany. We analyzed retrospectively collected data on breastfeeding from children aged 3-17 years who participated in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS baseline study) between 2003 and 2006 (n = 13163). To minimize confounding, we applied propensity score matching and multivariate logistic regression analyses to estimate the effect of breastfeeding on childhood overweight and obesity. Adjusted analyses of the matched dataset (n = 8034) indicated that children who were breastfed for >4 months had a significant reduction in the odds of overweight (OR 0.81 [95% CI 0.71–0.92]) and obesity (OR 0.75 [95% CI 0.61–0.92]) compared to children who were not breastfed or who were breastfed for a shorter duration [corrected].Further analyses stratified by age group showed that the association was strongest in children aged 7-10 years (OR 0.67 [95% CI 0.53-0.84] for overweight and OR 0.56 [95% CI 0.39-0.81] for obesity), while no significant effect could be seen in other age groups. Our findings support the hypothesis that breastfeeding does have a beneficial effect on childhood overweight and obesity, although the effect seems to be strongest in children of primary school age.
Mutagenic analysis of the nucleation propensity of oxidized Alzheimer's beta-amyloid peptide.
Christopeit, Tony; Hortschansky, Peter; Schroeckh, Volker; Gührs, Karlheinz; Zandomeneghi, Giorgia; Fändrich, Marcus
2005-08-01
The formation of polypeptide aggregates represents a nucleated polymerization reaction in which an initial nucleation event (lag phase) is followed by the extension of newly formed nuclei into larger aggregates, including fibrils (growth phase). The efficiencies of these reactions relate to the lag time (lag phase) and to the rate of aggregation (growth phase), which can be determined from experimental aggregation curves. Here we present a mutagenic analysis in which we replace valine 18 of the Alzheimer's Abeta (1-40) peptide with 17 different amino acids and determine its effect on the lag time, and therefore, on the propensity of nucleation. Comparison with various physico-chemical properties shows that nucleation is affected in a predictable manner depending on the beta-sheet propensity and hydrophobicity of residue 18. In addition, we observe a direct proportionality between the lag time and the rate of aggregation. These data imply that the two reactions, nucleation and polymerization, are governed by very similar physicochemical principles and that they involve the formation of the same types of noncovalent interactions.
Tsutaho, Akio; Nakamura, Toru; Asano, Toshimichi; Okamura, Keisuke; Tsuchikawa, Takahiro; Noji, Takehiro; Nakanishi, Yoshitsugu; Tanaka, Kimitaka; Murakami, Soichi; Kurashima, Yo; Ebihara, Yuma; Shichinohe, Toshiaki; Ito, Yoichi M; Hirano, Satoshi
2017-10-01
Delayed gastric emptying (DGE) is one of the most common morbidities of pancreaticoduodenectomy (PD). The aim of this study was to clarify whether the incidence of DGE can be reduced by side-to-side gastric greater curvature-to-jejunal anastomosis in subtotal stomach-preserving pancreaticoduodenectomy (SSPPD). The clinical data of 253 patients who had undergone PD were examined. Of a total of 188 patients who had undergone SSPPD, a gastrojejunostomy (GJ) was performed with end-to-side anastomosis in 87 patients (SSPPD-ETS group), and a GJ was performed with a greater curvature side-to-jejunal side anastomosis in 101 patients (SSPPD-STS group). After propensity score matching, the matched cohort consisted of 74 patients in each group. The postoperative data were evaluated according to the International Study Group of Pancreatic Surgery grade of DGE. The total incidence of DGE was 9.4% in the SSPPD-ETS group and 4% in the SSPPD-STS group, with no significant difference (p = 0.1902). A significant difference was observed between the two groups in the incidence of DGE grade C (p = 0.0426). The incidence of total DGE was not reduced statistically in the STS group compared with the ETS group, but reduced DGE grade C. Side-to-side anastomosis might be associated with a reduced incidence of DGE grade C.
Biswas, Aviroop; Smith, Peter M; Gignac, Monique A M
2018-06-01
The benefit of providing access to physical activity facilities at or near work to support the leisure time physical activity (LTPA) of workers is uncertain. We examined the association between access to physical activity facilities at or near work and the LTPA of workers after adjusting for a range of individual and occupational characteristics. Data was obtained from 60,650 respondents to the 2007-2008 Canadian Community Health Survey. Participants were employed adults ≥18 years of age who had no long-term health condition which reduced their participation in physical activity. Latent class analysis determined naturally occurring combinations of physical activity facilities at or near work. Each combination was balanced by 19 individual and occupational covariate characteristics using inverse probability of treatment weights derived from propensity scores. The association between combinations of physical activity facilities at or near work on LTPA level was estimated by multinomial logistic regression. Five different combinations of physical activity facilities were available to respondents at or near work. Data were analyzed in 2017. All possible physical facilities increased the likelihood for LTPA (OR, 2.08, 95% CI, 1.03-4.20) and other combinations were also positively associated. Respondents with no physical activity facilities were characterized as having a low education, low income, high physically demanding work, poor health and mental health, non-white racial background, and being an immigrant. Access to supportive workplace environments can help workers be physically active. Future research should assess a range of personal, social and environmental factors that may be driving this relationship.
Han, Yoonsun; Grogan-Kaylor, Andrew; Delva, Jorge; Xie, Yu
2014-11-17
When estimating the association between peer and youth alcohol consumption, it is critical to account for possible differential levels of response to peer socialization processes across youth, in addition to variability in individual, family, and social factors. Failure to account for intrinsic differences in youth's response to peers may pose a threat of selection bias. To address this issue, we used a propensity score stratification method to examine whether the size of the association between peer and youth drinking is contingent upon differential predicted probabilities of associating with alcohol-consuming friends. Analyzing a Chilean youth sample (N = 914) of substance use, we found that youths are susceptible to the detrimental role of peer drinkers, but the harmful relationship with one's own drinking behavior may be exacerbated among youth who already have a high probability of socializing with peers who drink. In other words, computing a single weighted-average estimate for peer drinking would have underestimated the detrimental role of peers, particularly among at-risk youths, and overestimated the role of drinking peers among youths who are less susceptible to peer socialization processes. Heterogeneous patterns in the association between peer and youth drinking may shed light on social policies that target at-risk youths.
Ruospo, Marinella; Palmer, Suetonia C; Wong, Germaine; Craig, Jonathan C; Petruzzi, Massimo; De Benedittis, Michele; Ford, Pauline; Johnson, David W; Tonelli, Marcello; Natale, Patrizia; Saglimbene, Valeria; Pellegrini, Fabio; Celia, Eduardo; Gelfman, Ruben; Leal, Miguel R; Torok, Marietta; Stroumza, Paul; Bednarek-Skublewska, Anna; Dulawa, Jan; Frantzen, Luc; Del Castillo, Domingo; Schon, Staffan; Bernat, Amparo G; Hegbrant, Jorgen; Wollheim, Charlotta; Gargano, Letizia; Bots, Casper P; Strippoli, Giovanni Fm
2017-05-22
Periodontitis is associated with cardiovascular mortality in the general population and adults with chronic diseases. However, it is unclear whether periodontitis predicts survival in the setting of kidney failure. ORAL-D was a propensity matched analysis in 3338 dentate adults with end-stage kidney disease treated in a hemodialysis network in Europe and South America designed to examine the association between periodontitis and all-cause and cardiovascular-related mortality in people on long-term hemodialysis. Participants were matched 1:1 on their propensity score for moderate to severe periodontitis assessed using the World Health Organization Community Periodontal Index. A random-effects Cox proportional hazards model was fitted with shared frailty to account for clustering of mortality risk within countries. Among the 3338 dentate participants, 1355 (40.6%) had moderate to severe periodontitis at baseline. After using propensity score methods to generate a matched cohort of participants with periodontitis similar to those with none or mild periodontal disease, moderate to severe periodontitis was associated with a lower risk of all-cause (9.1 versus 13.0 per 100 person years, hazard ratio 0.74, 95% confidence interval 0.61 to 0.90) and cardiovascular (4.3 versus 6.9 per 100 person years, hazard ratio 0.67, 0.51 to 0.88) mortality. These associations were not changed substantially when participants were limited to those with 12 or more natural teeth and when accounting for competing causes of cardiovascular death. In contrast to the general population, periodontitis does not appear to be associated with an increased risk of early death in adults treated with hemodialysis.
Garlipp, Benjamin; Ptok, Henry; Benedix, Frank; Otto, Ronny; Popp, Felix; Ridwelski, Karsten; Gastinger, Ingo; Benckert, Christoph; Lippert, Hans; Bruns, Christiane
2016-12-01
Adjuvant chemotherapy for resected rectal cancer is widely used. However, studies on adjuvant treatment following neoadjuvant chemoradiotherapy (CRT) and total mesorectal excision (TME) have yielded conflicting results. Recent studies have focused on adding oxaliplatin to both preoperative and postoperative therapy, making it difficult to assess the impact of adjuvant oxaliplatin alone. This study was aimed at determining the impact of (i) any adjuvant treatment and (ii) oxaliplatin-containing adjuvant treatment on disease-free survival in CRT-pretreated, R0-resected rectal cancer patients. Patients undergoing R0 TME following 5-fluorouracil (5FU)-only-based CRT between January 1, 2008, and December 31, 2010, were selected from a nationwide registry. After propensity score matching (PSM), comparison of disease-free survival (DFS) using Kaplan-Meier analysis and log-rank test was performed in (i) patients receiving no vs. any adjuvant treatment and (ii) patients treated with adjuvant 5FU/capecitabine without vs. with oxaliplatin. Out of 1497 patients, 520 matched pairs were generated for analysis of no vs. any adjuvant treatment. Mean DFS was significantly prolonged with adjuvant treatment (81.8 ± 2.06 vs. 70.1 ± 3.02 months, p < 0.001). One hundred forty-eight matched pairs were available for analysis of adjuvant therapy with or without oxaliplatin, showing no improvement in DFS in patients receiving oxaliplatin (76.9 ± 4.12 vs. 79.3 ± 4.44 months, p = 0.254). Local recurrence rate was not significantly different between groups in either analysis. In this cohort of rectal cancer patients treated with neoadjuvant CRT and TME surgery under routine conditions, adjuvant chemotherapy significantly improved DFS. No benefit was observed for the addition of oxaliplatin to adjuvant chemotherapy in this setting.
Bäumler, Michael; Stargardt, Tom; Schreyögg, Jonas; Busse, Reinhard
2012-07-01
The high number of patients with acute myocardial infarction (AMI) has facilitated greater research, resulting in the development of innovative medical devices. So far, results from economic evaluations that compared drug-eluting stents (DES) and bare-metal stents (BMS) have not shown clear evidence that one intervention is more cost effective than the other. The aim of this study was to measure the cost effectiveness of DES compared with BMS in routine care. We used administrative data from a large German sickness fund to compare the costs and effectiveness of DES and BMS in patients with AMI. Patients with hospital admission after AMI in 2004 and 2005 were followed up for 1 year after hospital discharge. The cost of treatment and survival after 365 days were compared for patients treated with DES and BMS. We adjusted for covariates defined according to the Ontario Acute Myocardial Infarction Mortality Prediction Rules using propensity score matching. After matching, we calculated incremental cost-effectiveness ratios (ICERs) by (i) using sample means based on bootstrapping procedures and (ii) estimating generalized linear mixed models for costs and survival. After propensity score matching, the sample included 719 patients treated with DES and 719 patients treated with BMS. A comparison of sample means resulted in average costs of € 12 714 and € 11 714 for DES and BMS, respectively, in 2005 German euros. Difference in 365-day survival was not statistically significant (700 patients with DES and 701 with BMS). The ICER of DES versus BMS was -€ 718 709 per life saved. Bootstrapping resulted in DES being dominated by BMS in 54.5% of replications and DES being a dominant strategy in 2.7% of replications. Results from regression models and sensitivity analyses confirm these results. Treatment with DES after admission with AMI is less cost effective than treatment with BMS. Our results are in line with other cost-effectiveness analyses that used administrative
Troeller, Almut; Yan, Di; Marina, Ovidiu; Schulze, Derek; Alber, Markus; Parodi, Katia; Belka, Claus; Söhn, Matthias
2015-02-01
This study compared normal tissue complication probability (NTCP) modeling of chronic gastrointestinal toxicities following prostate cancer treatment for 2 treatment modalities. Possible factors causing discrepancies in optimal NTCP model parameters between 3-dimensional conformal radiation therapy (3D-CRT) and intensity modulated RT (IMRT) were analyzed and discussed, including the impact of patient characteristics, image guidance, toxicity scoring bias, and NTCP model limitations. Rectal wall dose-volume histograms of 1115 patients treated for prostate cancer under an adaptive radiation therapy protocol were used to model gastrointestinal toxicity grade ≥2 (according to Common Terminology Criteria for Adverse Events). A total of 457 patients were treated with 3D-CRT and 658 with IMRT. 3D-CRT patients were matched to IMRT patients based on various patient characteristics, using a propensity score-based algorithm. Parameters of the Lyman equivalent uniform dose and cut-off dose logistic regression NTCP models were estimated for the 2 matched treatment modalities and the combined group. After they were matched, the 3D-CRT and IMRT groups contained 275 and 550 patients with a large discrepancy of 28.7% versus 7.8% toxicities, respectively (P<.001). For both NTCP models, optimal parameters found for the 3D-CRT groups did not fit the IMRT patients well and vice versa. Models developed for the combined data overestimated NTCP for the IMRT patients and underestimated NTCP for the 3D-CRT group. Our analysis did not reveal a single definitive cause for discrepancies of model parameters between 3D-CRT and IMRT. Patient characteristics and bias in toxicity scoring, as well as image guidance alone, are unlikely causes of the large discrepancy of toxicities. Whether the cause was inherent to the specific NTCP models used in this study needs to be verified by future investigations. Because IMRT is increasingly used clinically, it is important that appropriate NTCP model
Okuzono, Sakurako; Fujiwara, Takeo; Kato, Tsuguhiko; Kawachi, Ichiro
2017-07-01
Harsh or frequent spanking in early childhood is an established risk factor for later childhood behavioral problems as well as mental disorder in adulthood in Western societies. However, few studies have been conducted in Asian populations, where corporal punishment is relatively accepted. Moreover, the impacts of occasional spanking on subsequent behavioral problems remain uncertain. This study sought to investigate prospectively the association between the frequency of spanking of toddlers and later behavioral problems in Japanese children using national birth cohort data. We used data from the Longitudinal Survey of Newborns in the 21st Century, a population-based birth cohort data set collected by the Japanese Ministry of Health, Labour, and Welfare (N=29,182). Frequency of spanking ("never", "sometimes" and "always") and child behavioral problems were assessed via a caregiver questionnaire when the child was 3.5 years old and again at 5.5 years. Propensity score matching was used to examine the association between frequency of spanking and child behavioral problems, adjusting for parental socioeconomic status, child temperament and parenting behaviors. Compared to children who were never spanked, occasional spanking ("sometimes") showed a higher number of behavioral problems (on a 6-point scale) (coefficient: 0.11, 95% CI: 0.07-0.15), and frequent spanking ("always") showed an even larger number of behavioral problems compared with "sometimes" (coefficient: 0.08, 95% CI:0.01-0.16). Spanking of any self-reported frequency was associated with an increased risk for later behavioral problems in children. Copyright © 2017 Elsevier Ltd. All rights reserved.
Park, Suyeon; Kim, Won Gu; Han, Minkyu; Jeon, Min Ji; Kwon, Hyemi; Kim, Mijin; Sung, Tae-Yon; Kim, Tae Yong; Kim, Won Bae; Hong, Suck Joon; Shong, Young Kee
2017-09-01
Thyrotropin (TSH) suppression has improved the clinical outcomes of patients with differentiated thyroid cancer (DTC). However, the efficacy of TSH suppressive therapy (TST) is unclear in patients with low-risk DTC. This study aimed to evaluate the efficacy of TST and optimal TSH levels of patients with low-risk DTC. This retrospective propensity score-matched cohort study included DTC patients (n = 446) who underwent lobectomy from 2002 to 2008 with or without TST (TST group and No-TST group). Disease-free survival (DFS) and dynamic risk stratification were compared between both groups using serum TSH levels. Approximately 74% of TST patients and 11% of No-TST patients had suppressed serum TSH levels (<2 mIU/L). The median follow-up period was 8.6 years. During follow-up, the disease recurred in 10 (2.7%) patients, with no significant difference in DFS between the groups (p = 0.63). The proportion of patients with excellent treatment response was similar between the TST (65.2%) and No-TST (64.4%) groups. Incomplete biochemical response was noted in 17.2% of the TST group patients and 9.4% of the No-TST group patients. No significant difference was observed in the DFS between both groups by comparing serum TSH level (p = 0.57). TST did not improve clinical outcomes, and serum TSH levels were not associated with recurrence in patients with low-risk small DTC. No clinical benefits were shown for TSH suppression in low-risk patients who underwent lobectomy. Thus, levothyroxine is not necessary for patients without evidence of hypothyroidism.
de Vocht, F; Campbell, R; Brennan, A; Mooney, J; Angus, C; Hickman, M
2016-03-01
Area-level public health interventions can be difficult to evaluate using natural experiments. We describe the use of propensity score matching (PSM) to select control local authority areas (LAU) to evaluate the public health impact of alcohol policies for (1) prospective evaluation of alcohol policies using area-level data, and (2) a novel two-stage quasi case-control design. Ecological. Alcohol-related indicator data (Local Alcohol Profiles for England, PHE Health Profiles and ONS data) were linked at LAU level. Six LAUs (Blackpool, Bradford, Bristol, Ipswich, Islington, and Newcastle-upon-Tyne) as sample intervention or case areas were matched to two control LAUs each using PSM. For the quasi case-control study a second stage was added aimed at obtaining maximum contrast in outcomes based on propensity scores. Matching was evaluated based on average standardized absolute mean differences (ASAM) and variable-specific P-values after matching. The six LAUs were matched to suitable control areas (with ASAM < 0.20, P-values >0.05 indicating good matching) for a prospective evaluation study that sought areas that were similar at baseline in order to assess whether a change in intervention exposure led to a change in the outcome (alcohol related harm). PSM also generated appropriate matches for a quasi case-control study--whereby the contrast in health outcomes between cases and control areas needed to be optimized in order to assess retrospectively whether differences in intervention exposure were associated with the outcome. The use of PSM for area-level alcohol policy evaluation, but also for other public health interventions, will improve the value of these evaluations by objective and quantitative selection of the most appropriate control areas. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
The “Dry-Run” Analysis: A Method for Evaluating Risk Scores for Confounding Control
Wyss, Richard; Hansen, Ben B.; Ellis, Alan R.; Gagne, Joshua J.; Desai, Rishi J.; Glynn, Robert J.; Stürmer, Til
2017-01-01
Abstract A propensity score (PS) model's ability to control confounding can be assessed by evaluating covariate balance across exposure groups after PS adjustment. The optimal strategy for evaluating a disease risk score (DRS) model's ability to control confounding is less clear. DRS models cannot be evaluated through balance checks within the full population, and they are usually assessed through prediction diagnostics and goodness-of-fit tests. A proposed alternative is the “dry-run” analysis, which divides the unexposed population into “pseudo-exposed” and “pseudo-unexposed” groups so that differences on observed covariates resemble differences between the actual exposed and unexposed populations. With no exposure effect separating the pseudo-exposed and pseudo-unexposed groups, a DRS model is evaluated by its ability to retrieve an unconfounded null estimate after adjustment in this pseudo-population. We used simulations and an empirical example to compare traditional DRS performance metrics with the dry-run validation. In simulations, the dry run often improved assessment of confounding control, compared with the C statistic and goodness-of-fit tests. In the empirical example, PS and DRS matching gave similar results and showed good performance in terms of covariate balance (PS matching) and controlling confounding in the dry-run analysis (DRS matching). The dry-run analysis may prove useful in evaluating confounding control through DRS models. PMID:28338910
Won, Ki-Bum; Hur, Seung-Ho; Nam, Chang-Wook; Ann, Soe Hee; Park, Gyung-Min; Lee, Sang-Gon; Kim, Hyo-Eun; Cho, Yun-Kyeong; Yoon, Hyuck-Jun; Park, Hyoung-Seob; Kim, Hyungseop; Han, Seongwook; Jeong, Myung-Ho; Ahn, Young-Keun; Rha, Seung-Woon; Kim, Chong-Jin; Cho, Myeong-Chan; Kim, Hyo-Soo; Chae, Shung-Chull; Kim, Kee-Sik; Kim, Young-Jo; Kim, Kwon-Bae; Barter, Philip
2017-09-01
The phenomenon of obesity paradox after acute myocardial infarction (AMI) has been reported under strong recommendation of statin therapy. However, the impact of statin therapy on this paradox has not been investigated. This study investigated the impact of statin therapy on 1-year mortality according to obesity after AMI. A total of 2745 AMI patients were included from the Korea Acute Myocardial Infarction Registry after 1:4 propensity score matching analysis (n = 549 for nonstatin group and n = 2196 for statin group). Primary and secondary outcomes were all-cause and cardiac death, respectively. During 1-year follow-up, the incidence of all-cause (8.4% vs 3.7%) and cardiac (6.2% vs 2.3%) death was higher in nonstatin group than in statin (P < .001, respectively). In nonstatin group, the incidence of all-cause (7.2% vs 9.0%) and cardiac (5.5% vs 6.5%) death did not differ significantly between obese and nonobese patients. However, in statin group, obese patients had lower 1-year rate of all-cause (1.7% vs 4.8%) and cardiac (1.2% vs 2.9%) death (P < .05, respectively), and lower cumulative rates by Kaplan-Meier analysis of all-cause and cardiac death compared with nonobese patients (log-rank P < .05, respectively). The overall risk of all-cause death was significantly lower in obese than in nonobese patients only in statin group (hazard ratio: 0.35; P = .001). After adjusting for confounding factors, obesity was independently associated with decreased risk of all-cause death in statin group. In conclusion, the greater benefit of statin therapy for survival in obese patients is further confirmation of the obesity paradox after AMI.
Xu, Cheng; Liu, Xu; Chen, Yu-Pei; Mao, Yan-Ping; Guo, Rui; Zhou, Guan-Qun; Tang, Ling-Long; Lin, Ai-Hua; Sun, Ying; Ma, Jun
2017-12-01
The impact of marital status at diagnosis on survival outcomes and its change over time in patients with nasopharyngeal carcinoma (NPC) are unclear. The Surveillance, Epidemiology, and End Results (SEER) database was used to identify patients diagnosed with NPC in the United States from 1973 to 2012. A primary comparison (married vs. unmarried) was implemented with 1:1 propensity score matching. Secondary comparisons were performed individually between three unmarried subgroups (single, separated/divorced, widowed) and married group. The effect of marital status on cause-specific survival (CSS) and overall survival (OS) were evaluated using univariate/multivariate analysis. Moreover, we investigated the change over time (1973-2012) in the effect of marital status on NPC survival. Married patients had better 5-year CSS/OS than unmarried patients (61.1% vs. 52.6%, P < 0.001; 55.6% vs. 45.3%, P < 0.001, respectively). In multivariate analysis, unmarried patients had significantly poorer CSS/OS than married patients (adjusted hazard ratio [aHR] = 1.35, P < 0.001; aHR = 1.40, P < 0.001, respectively). The survival benefit of being married was only detected in non-Hispanic white and Chinese American patients. Single, separated/divorced, and widowed patients had significantly poorer CSS/OS than married patients (aHR = 1.37 and 1.37; 1.46 and 1.42; 1.43 and 1.48, respectively; all P < 0.001). The change over time in the effect of marital status on survival was more stable in male than female. The strength of the negative effect of separated/divorced and widowed status showed a downward and upward trend, respectively. Gender difference in the adverse effect of single status on NPC survival became smaller over time. Only non-Hispanic white and Chinese American patients with NPC obtain survival benefits from married status. Single and widowed patients are regarded as high-risk population. © 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.
Shiraishi, Yutaka; Fang, Penny; Xu, Cai; Song, Juhee; Krishnan, Sunil; Koay, Eugene J; Mehran, Reza J; Hofstetter, Wayne L; Blum-Murphy, Mariela; Ajani, Jaffer A; Komaki, Ritsuko; Minsky, Bruce; Mohan, Radhe; Hsu, Charles C; Hobbs, Brian P; Lin, Steven H
2017-12-13
Circulating lymphocytes are exquisitely sensitive to radiation exposure, even to low scattered doses which can vary drastically between radiation modalities. We compared the relative risk of radiation-induced lymphopenia between intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT) in esophageal cancer (EC) patients undergoing neoadjuvant chemoradiation therapy (nCRT). EC patients treated with IMRT and PBT were propensity matched based on key clinical variables. Treatment-associated lymphopenia was graded using CTCAE v.4.0. Using matched cohorts, univariate and multivariable multiple logistic regression was used to identify factors associated with increased risk of grade 4 lymphopenia as well as characterize their relative contributions. Among the 480 patients treated with nCRT, 136 IMRT patients were propensity score matched with 136 PBT patients. In the matched groups, a greater proportion of the IMRT patients (55/136, 40.4%) developed grade 4 lymphopenia during nCRT compared with the PBT patients (24/136, 17.6%, P < 0.0001). On multivariable analysis, PBT was significantly associated with a reduction in grade 4 lymphopenia risk (odds ratio, 0.29; 95% confidence interval, 0.16-0.52; P < 0.0001). PBT is associated with significant risk reduction in grade 4 lymphopenia during nCRT in esophageal cancer. Copyright © 2017 Elsevier B.V. All rights reserved.
Tóth, Roland; Szántó, Péter; Prodán, Zsolt; Lex, Daniel J; Sápi, Erzsébet; Szatmári, András; Gál, János; Szántó, Tamás; Székely, Andrea
2013-10-01
The incidence of congenital heart disease is ~50%, mostly related to endocardial cushion defects. The aim of our study was to investigate the postoperative complications that occur after paediatric cardiac surgery. Our perioperative data were analysed in paediatric patients with Down syndrome undergoing cardiac surgery. We retrospectively analysed the data from 2063 consecutive paediatric patients between January 2003 and December 2008. After excluding the patients who died or had missing data, the analysed database (before propensity matching) contained 129 Down patients and 1667 non-Down patients. After propensity matching, the study population comprised 222 patients and 111 patients had Down syndrome. Before propensity matching, the occurrences of low output syndrome (21.2 vs 32.6%, P = 0.003), pulmonary complication (14 vs 28.7%, P < 0.001) and severe infection (11.9 vs 22.5%, P = 0.001) were higher in the Down group. Down patients were more likely to have prolonged mechanical ventilation [median (interquartile range) 22 (9-72) h vs 49 (24-117) h, P = 0.007]. The total intensive care unit length of stay [6.9 (4.2-12.4) days vs 8.3 (5.3-13.2) days, P = 0.04] and the total hospital length of stay [17.3 (13.3-23.2) days vs 18.3 (15.1-23.6) days, P = 0.05] of the Down patients were also longer. Mortality was similar in the two groups before (3.58 vs 3.88%, P = 0.86) and after (5.4 vs 4.5%, P = 1.00) propensity matching. After propensity matching, there was no difference in the occurrence of adverse events. After propensity matching Down syndrome was not associated with increased mortality or complication rate following congenital cardiac surgery.
Yun, Yeo-Hon; Kwon, Soon-Sun; Koh, Youngdo; Kim, Dong-Jun; Ahn, Jonghyun; Lee, Seung Yeol
2017-09-06
We performed this study to investigate the influence of recombinant human growth hormone (rhGH) therapy on radiographic indices of the spine using propensity-matched analysis. Patients with idiopathic short stature who had undergone both growth hormone therapy and whole-spine radiographs more than twice prior to 15 years of age were included in the patient group. Other patients who had undergone whole-spine radiographs more than twice prior to the same age during regular checkups for idiopathic scoliosis formed the control group. Propensity-matched analysis was performed to reduce the selection bias. The scoliosis Cobb angle, coronal balance, apical vertebral translation, apical rotation, and pelvic obliquity were measured from the radiographs taken at the periodic follow-ups. The rate of progression of the measurements was adjusted by multiple factors using a linear mixed model with sex as the fixed effect and age and each subject as the random effects. Using a propensity-matched analysis, 48 patients were finally included in both groups. The scoliosis Cobb angle increased by 1.0° (p < 0.001) per year in the patient group, whereas there was no significant annual change in the control group (p = 0.496). Female patients showed a greater scoliosis Cobb angle (1.8°, p = 0.039) compared with male patients. There was no significant difference between the patient and control groups in coronal balance (p = 0.264). Apical vertebral translation per year was increased by 1.2 mm (p < 0.001) in the patient group and 0.5 mm in the control group (p = 0.003). Radiographic examination revealed that growth hormone therapy for idiopathic short stature affected the progression of the scoliosis Cobb angle and apical vertebral translation on the coronal plane. Physicians should be aware that annual follow-up is required to evaluate the change in the curvature of the spine in patients undergoing rhGH treatment.
Hsieh, Chih-Chia; Lee, Chung-Hsun; Hong, Ming-Yuan; Hung, Yuan-Pin; Lee, Nan-Yao; Ko, Wen-Chien; Lee, Ching-Chi
2016-12-01
In this study, the therapeutic efficacy of cefazolin was compared with that of extended-spectrum cephalosporins (ESCs) (cefotaxime, ceftriaxone and ceftazidime) as appropriate empirical therapy in adults with community-onset monomicrobial bacteraemia caused by Escherichia coli, Klebsiella spp. or Proteus mirabilis (EKP). Compared with cefazolin-treated patients (n = 135), significantly higher proportions of patients in the ESC treatment group (n = 456) had critical illness at bacteraemia onset (Pitt bacteraemia score ≥4) and fatal co-morbidities (McCabe classification). Of the 591 patients, 121 from each group were matched using propensity score matching (PSM) based on the following independent predictors of 28-day mortality: fatal co-morbidities (McCabe classification); Pitt bacteraemia score ≥4 at bacteraemia onset; initial syndrome of septic shock; and bacteraemia due to pneumonia. After appropriate PSM, no significant differences were observed in the early clinical failure rate (10.7% vs. 7.4%; P = 0.37), the proportion of critical illness (Pitt bacteraemia score ≥4) (0% vs. 0%; P = 1.00) and defervescence (52.6% vs. 42.6%; P = 0.13) on Day 3 between the cefazolin and ESC treatment groups. Similarly, no significant differences were observed in the mean of time to defervescence (4.1 days vs. 4.9 days; P = 0.15), late clinical failure rate (18.2% vs. 10.7%; P = 0.10) and 28-day crude mortality rate (0.8% vs. 3.3%; P = 0.37) between the two groups. These data suggest that the efficacy of cefazolin is similar to that of ESCs when used as appropriate empirical antimicrobial treatment for community-onset EKP bacteraemia. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.
2010-03-01
policy (Achen & Snidal, 1989). Huth and Russett (1984) emphasize : “if we do not know how deterrence works when it is most needed, policies assigned...application of deterrence to U.S. adversaries in these policies. Analysis of risk propensity and relative emphases on loss/gain of those actors...research, the strategic environment. Evidence of such assessment may reflect an adversary’s risk propensities and relative emphases on loss/gain; however
Takahashi, Koichi; Kantarjian, Hagop M; Yang, Yulong; Sasaki, Koji; Jain, Preetesh; DellaSala, Sara; Ravandi, Farhad; Kadia, Tapan; Pemmaraju, Naveen; Daver, Naval; Borthakur, Gautam; Garcia-Manero, Guillermo; Jabbour, Elias; Cortes, Jorge E
2016-11-15
Both dasatinib and nilotinib are approved frontline therapy for chronic myeloid leukemia in chronic phase (CML-CP) based on randomized trials compared with imatinib. However, no head-to-head comparison of dasatinib and nilotinib has been conducted in patients with newly diagnosed CML-CP. The authors conducted a propensity score (PS) matched comparison of patients with CML-CP who received frontline therapy with either dasatinib (N = 102) or nilotinib (N = 104) under the respective phase 2 trials conducted in parallel. PS matching resulted in 87 patients from each trial being matched for pretreatment characteristics. The 3-month BCR-ABL1/ABL1 ratio <10% rate was 93% with dasatinib and 94% with nilotinib (P = .25); the rates of major molecular response at 12 months were 77% and 85%, respectively (P = .13); and the rates of molecular response with 4.5-log reduction in the ratio at 36 months were 66% and 64%, respectively (P = .96). All other clinically relevant responses were similar between the 2 treatment cohorts. The 3-year probability of event-free survival was 89% among the patients who received dasatinib and 87% among those who received nilotinib (P = .99), and the corresponding 3-year overall survival probabilities were 99% and 93%, respectively (P = .95). No statistical difference was observed between the dasatinib and nilotinib groups in any of the other survival endpoints. The treatment discontinuation rate also was similar between the 2 cohorts (dasatinib group, 18%; nilotinib group, 19%; P = .82). In a PS-matched cohort of patients with newly diagnosed CML-CP, dasatinib and nilotinib offer similar response and survival outcomes. Both drugs can be considered reasonable standard-of-care options as first-line therapy for patients with CML-CP. Cancer 2016;122:3336-3343. © 2016 American Cancer Society. © 2016 American Cancer Society.
Kunihara, Takashi; Wendler, Olaf; Heinrich, Kerstin; Nomura, Ryota; Schäfers, Hans-Joachim
2018-06-20
The optimal choice of conduit and configuration for coronary artery bypass grafting (CABG) in diabetic patients remains somewhat controversial, even though arterial grafts have been proposed as superior. We attempted to clarify the role of complete arterial revascularization using the left internal thoracic artery (LITA) and the radial artery (RA) alone in "T-Graft" configuration on long-term outcome. From 1994 to 2001, 104 diabetic patients with triple vessel disease underwent CABG using LITA/RA "T-Grafts" (Group-A). Using propensity-score matching, 104 patients with comparable preoperative characteristics who underwent CABG using LITA and one sequential vein graft were identified (Group-V). Freedom from all causes of death, cardiac death, major adverse cardiac event (MACE), major adverse cardiac (and cerebral) event (MACCE), and repeat revascularization at 10 years of Group-A was 60 ± 5%, 67 ± 5%, 48 ± 5%, 37 ± 5%, and 81 ± 4%, respectively, compared with 58 ± 5%, 70 ± 5%, 49 ± 5%, 39 ± 5%, and 93 ± 3% in Group-V. There were no significant differences in these end points between groups regardless of insulin-dependency. Multivariable Cox proportional hazards model identified age, left ventricular ejection fraction, renal failure, and hyperlipidemia as independent predictors for all death, age and left ventricular ejection fraction for cardiac death, sinus rhythm for both MACE and MACCE, and prior percutaneous coronary intervention for re-revascularization. In our experience, complete arterial revascularization using LITA/RA "T-Grafts" does not provide superior long-term clinical benefits for diabetic patients compared with a combination of LITA and sequential vein graft. Georg Thieme Verlag KG Stuttgart · New York.
Kim, Jae-Hyun; Lee, Kwang-Soo; Yoo, Ki-Bong; Park, Eun-Cheol
2015-01-01
Study Objectives Health care utilization has progressively increased, especially among Medical Aid beneficiaries in South Korea. The Medical Aid classifies beneficiaries into two categories, type 1 and 2, on the basis of being incapable (those under 18 or over 65 years of age, or disabled) or capable of working, respectively. Medical Aid has a high possibility for health care utilization due to high coverage level. In South Korea, the national health insurance (NHI) achieved very short time to establish coverage for the entire Korean population. However there there remaine a number of problems to be solved. Therefore, the objective of this study was to investigate the differences in health care utilization between Medical Aid beneficiaries and Health Insurance beneficiaries. Methods & Design Data were collected from the Korean Welfare Panel Study from 2008 to 2012 using propensity score matching. Of the 2,316 research subjects, 579 had Medical Aid and 1,737 had health insurance. We also analyzed three dependent variables: days spent in the hospital, number of outpatient visits, and hospitalizations per year. Analysis of variance and longitudinal data analysis were used. Results The number of outpatient visits was 1.431 times higher (p<0.0001) in Medical Aid beneficiaries, the number of hospitalizations per year was 1.604 times higher (p<0.0001) in Medical Aid beneficiaries, and the number of days spent in the hospital per year was 1.282 times higher (p<0.268) for Medical Aid beneficiaries than in individuals with Health Insurance. Medical Aid patients had a 0.874 times lower frequency of having an unmet needs due to economic barrier (95% confidence interval: 0.662-1.156). Conclusions Health insurance coverage has an impact on health care utilization. More health care utilization among Medical Aid beneficiaries appears to have a high possibility of a moral hazard risk under the Health Insurance program. Therefore, the moral hazard for Medical Aid beneficiaries
Muruet, Walter; Rudd, Anthony; Wolfe, Charles D A; Douiri, Abdel
2018-03-01
Intravenous thrombolysis with alteplase is one of the few approved treatments for acute ischemic stroke; nevertheless, little is known about its long-term effects on survival and recovery because clinical trials follow-up times are limited. Patients registered between January 2005 and December 2015, to the population-based South London Stroke Register of first-ever strokes. Propensity score was used to match thrombolyzed and control cases to a 1:2 ratio by demographical and clinical covariates. The primary outcome was survival up to 10 years using Kaplan-Meier estimates, Cox proportional hazards, and restricted mean survival time. Secondary outcomes included stroke recurrence and functional status (Barthel Index and Frenchay Activities Index scores) at 5 years. From 2052 ischemic strokes, 246 treated patients were matched to 492 controls. Median follow-up time 5.45 years (interquartile range, 4.56). Survival was higher in the treatment group (median, 5.72 years) compared with control group (4.98 years, stratified log-rank test <0.001). The number needed to treat to prevent 1 death at 5 years was 12 and 20 at 10 years. After Cox regression analysis, thrombolysis reduced risk of mortality by 37% (hazard ratio, 0.63; 95% confidence interval [CI], 0.48-0.82) at 10 years; however, after introducing a multiplicative interaction term into the model, mortality risk reduction was 42% (hazard ratio, 0.58; 95% CI, 0.40-0.82) at 10 years for those arriving within 3 hours to the hospital. On average, in a 10-year period, treated patients lived 1 year longer than controls. At 5 years, thrombolysis was associated with independence (Barthel Index≥90; odds ratio, 3.76; 95% CI, 1.22-13.34) and increased odds of a higher Frenchay Activities Index (proportional odds ratio, 2.37; 95% CI, 1.16-4.91). There was no difference in stroke recurrence. Thrombolysis with intravenous alteplase is associated with improved long-term survival and functional status after ischemic stroke. © 2018
Two-step estimation in ratio-of-mediator-probability weighted causal mediation analysis.
Bein, Edward; Deutsch, Jonah; Hong, Guanglei; Porter, Kristin E; Qin, Xu; Yang, Cheng
2018-04-15
This study investigates appropriate estimation of estimator variability in the context of causal mediation analysis that employs propensity score-based weighting. Such an analysis decomposes the total effect of a treatment on the outcome into an indirect effect transmitted through a focal mediator and a direct effect bypassing the mediator. Ratio-of-mediator-probability weighting estimates these causal effects by adjusting for the confounding impact of a large number of pretreatment covariates through propensity score-based weighting. In step 1, a propensity score model is estimated. In step 2, the causal effects of interest are estimated using weights derived from the prior step's regression coefficient estimates. Statistical inferences obtained from this 2-step estimation procedure are potentially problematic if the estimated standard errors of the causal effect estimates do not reflect the sampling uncertainty in the estimation of the weights. This study extends to ratio-of-mediator-probability weighting analysis a solution to the 2-step estimation problem by stacking the score functions from both steps. We derive the asymptotic variance-covariance matrix for the indirect effect and direct effect 2-step estimators, provide simulation results, and illustrate with an application study. Our simulation results indicate that the sampling uncertainty in the estimated weights should not be ignored. The standard error estimation using the stacking procedure offers a viable alternative to bootstrap standard error estimation. We discuss broad implications of this approach for causal analysis involving propensity score-based weighting. Copyright © 2018 John Wiley & Sons, Ltd.
Shepherd-Banigan, Megan; Smith, Valerie A.; Stechuchak, Karen M.; Miller, Katherine E. M.; Hastings, Susan Nicole; Wieland, Gilbert Darryl; Olsen, Maren K.; Kabat, Margaret; Henius, Jennifer; Campbell-Kotler, Margaret; Van Houtven, Courtney Harold
2018-01-01
Family caregivers are an important component of the long-term services and supports (LTSS) system. However, caregiving may have negative consequences for caregiver physical and emotional health. Connecting caregivers to formal short-term home- and community-based services (HCBS), through information resources and referrals, might alleviate family caregiver burden and delay nursing home entry for the patient. The aim of this study was to evaluate the early impact of the Program of Comprehensive Assistance for Family Caregivers (PCAFC) (established by P.L. 111-163 for family caregivers of seriously injured post-9/11 Veterans) on Veteran use of LTSS. A two-cohort pre-post design with a nonequivalent comparison group (treated n = 15 650; comparison n = 8339) was used to (1) examine the association between caregiver enrollment in PCAFC and any VA-purchased or VA-provided LTSS use among Veterans and (2) describe program-related trends in HCBS and institutional LTSS use. The comparison group was an inverse-propensity-score weighted sample of Veterans whose caregivers applied for, but were not accepted into, the program. From baseline through 24 months post application, use of any LTSS ranged from 13.1% to 17.8% for Veterans whose caregivers were enrolled in PCAFC versus from 3.8% to 5.3% for Veterans in the comparison group. Participation in PCAFC was associated with a statistically significant increased use of any LTSS from 1 to 24 months post application (over time odds ratios ranged from 2.71 [95% confidence interval: 2.31-3.17] to 4.86 [3.93-6.02]). Support for family caregivers may enhance utilization of LTSS for Veterans with physical, emotional, and/or cognitive conditions. PMID:29591540
Coleman, Craig I; Peacock, W Frank; Bunz, Thomas J; Beyer-Westendorf, Jan
2018-05-30
In phase III trials, rivaroxaban demonstrated non-inferiority over enoxaparin/warfarin to prevent recurrent venous thromboembolism (VTE), with a reduction of major bleeding. However, compared to provoked VTE, the risk-benefit ratio of rivaroxaban may be different for patients with unprovoked VTE. In a retrospective claims data analysis using US MarketScan claims from 1/2012 to 12/2016, we included adults with a primary diagnosis of VTE newly-initiated on rivaroxaban or warfarin within 30-days of the incident VTE and with ≥12-months of continuous insurance benefits prior to the VTE (baseline). Patients with provoked VTE, a claim for anticoagulation during baseline or who redeemed prescriptions for ≥1 oral anticoagulant were excluded. Our primary outcomes were recurrent VTE and major bleeding at 6-months using an intention-to-treat (ITT) analysis. Three-month ITT and 12-month on-treatment (30-day permissible gap) analyses were also performed. Inverse probability-of-treatment weights based on propensity-scores and Cox regression were used to compare outcomes. We identified 10,489 rivaroxaban users and 26,364 warfarin users with incident unprovoked VTE. At 6-months, rivaroxaban was associated with a hazard ratio (HR) of 0.60 (95% confidence interval [CI] = 0.54-0.67) for recurrent VTE (number-needed-to-treat: 59; 95%CI 49-76) and a HR = 0.80 (95% CI = 0.66-0.98) for major bleeding versus warfarin. Our findings remained consistent in the 3- and 12-month analyses. Consistent with the results from the EINSTEIN phase-III trials, findings of our routine practice study suggest that, in patients with unprovoked VTE, rivaroxaban has the potential to reduce both the risk of major bleeding and recurrent VTE compared to warfarin. Copyright © 2018 Elsevier Ltd. All rights reserved.
Propensity, Probability, and Quantum Theory
NASA Astrophysics Data System (ADS)
Ballentine, Leslie E.
2016-08-01
Quantum mechanics and probability theory share one peculiarity. Both have well established mathematical formalisms, yet both are subject to controversy about the meaning and interpretation of their basic concepts. Since probability plays a fundamental role in QM, the conceptual problems of one theory can affect the other. We first classify the interpretations of probability into three major classes: (a) inferential probability, (b) ensemble probability, and (c) propensity. Class (a) is the basis of inductive logic; (b) deals with the frequencies of events in repeatable experiments; (c) describes a form of causality that is weaker than determinism. An important, but neglected, paper by P. Humphreys demonstrated that propensity must differ mathematically, as well as conceptually, from probability, but he did not develop a theory of propensity. Such a theory is developed in this paper. Propensity theory shares many, but not all, of the axioms of probability theory. As a consequence, propensity supports the Law of Large Numbers from probability theory, but does not support Bayes theorem. Although there are particular problems within QM to which any of the classes of probability may be applied, it is argued that the intrinsic quantum probabilities (calculated from a state vector or density matrix) are most naturally interpreted as quantum propensities. This does not alter the familiar statistical interpretation of QM. But the interpretation of quantum states as representing knowledge is untenable. Examples show that a density matrix fails to represent knowledge.
Hur, Min; Koo, Chang-Hoon; Lee, Hyung-Chul; Park, Sun-Kyung; Kim, Minkyung; Kim, Won Ho; Kim, Jin-Tae; Bahk, Jae-Hyon
2017-01-01
The association between preoperative aspirin use and postoperative acute kidney injury (AKI) in cardiovascular surgery is unclear. We sought to evaluate the effect of preoperative aspirin use on postoperative AKI in cardiac surgery. A total of 770 patients who underwent cardiovascular surgery under cardiopulmonary bypass were reviewed. Perioperative clinical parameters including preoperative aspirin administration were retrieved. We matched 108 patients who took preoperative aspirin continuously with patients who stopped aspirin more than 7 days or did not take aspirin for the month before surgery. The parameters used in the matching included variables related to surgery type, patient's demographics, underlying medical conditions and preoperative medications. In the first seven postoperative days, 399 patients (51.8%) developed AKI, as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria and 128 patients (16.6%) required hemodialysis. Most patients took aspirin 100 mg once daily (n = 195, 96.5%) and the remaining 75 mg once daily. Multivariable analysis showed that preoperative maintenance of aspirin was independently associated with decreased incidence of postoperative AKI (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.21-0.98, P = 0.048; after propensity score matching: OR 0.39, 95% CI 0.22-0.67, P = 0.001). Preoperative maintenance of aspirin was associated with less incidence of AKI defined by KDIGO both in the entire and matched cohort (n = 44 [40.7%] vs. 69 [63.9%] in aspirin and non-aspirin group, respectively in matched sample, relative risk [RR] 0.64, 95% CI 0.49, 0.83, P = 0.001). Preoperative aspirin was associated with decreased postoperative hospital stay after matching (12 [9-18] days vs. 16 [10-25] in aspirin and non-aspirin group, respectively, P = 0.038). Intraoperative estimated or calculated blood loss using hematocrit difference and estimated total blood volume showed no difference according to aspirin administration
Agrinier, Nelly; Schockmel, Matthieu; Thilly, Nathalie; Laborde-Castérot, Hervé; Jourdain, Patrick; Alla, François; Leclercq, Christophe; Dany, François; Druelle, Justine; Drouet, Emilie; Mulak, Geneviève; Juillière, Yves
2018-01-01
Patient education programmes (PEP) are recommended for patients with heart failure but have not been specifically assessed in heart failure with preserved ejection fraction (HFpEF). To assess the effectiveness of a structured PEP in reducing all-cause mortality in patients with HFpEF. Patients with HFpEF were selected from the ODIN cohort, designed to assess PEP effectiveness in patients with HF whatever their ejection fraction, included from 2007 to 2010, and followed up until 2013. Baseline sociodemographic, clinical, biological and therapeutic characteristics were collected. At inclusion, patients were invited to participate in the PEP, which consisted of educational diagnosis, education sessions and final evaluation. Education focused on HF pathophysiology and medication, symptoms of worsening HF, dietary recommendations and management of exercise. Propensity score matching and Cox models were performed. Of 849 patients with HFpEF, 572 (67.4%) participated in the PEP and 277 (32.6%) did not. Patients who participated in the PEP were younger (67.0±13.1 vs 76.1±13.2 years; standardized difference [StDiff] =-54.6%), less often women (39.7% vs 48.4%; StDiff =-17.6%) and presented more often with hypercholesterolaemia (55.2% vs 35.2%; StDiff 41.2%), smoking (35.1% vs 28.7%; StDiff 13.8%), alcohol abuse (14.1% vs 8.9%; StDiff 16.5%) and ischaemic HF (38.7% vs 29.2%; StDiff 20.0%) than those who did not; they also presented with better clinical cardiovascular variables. After propensity score matching, baseline characteristics were balanced, except hypertension (postmatch StDiff 19.1%). The PEP was associated with lower all-cause mortality (pooled hazard ratio 0.70, 95% confidence interval 0.49-0.99; P=0.042). This association remained significant after adjustment for hypertension (adjusted pooled hazard ratio 0.68, 95% confidence interval 0.48-0.97; P=0.036). In this investigation, a structured PEP was associated with lower all-cause mortality. Patient education
Ganapathi, Asvin M.; Hanna, Jennifer M.; Schechter, Matthew A.; Englum, Brian R.; Castleberry, Anthony W.; Gaca, Jeffrey G.; Hughes, G. Chad
2015-01-01
Objective The choice of cerebral perfusion strategy for aortic arch surgery has been debated, and the superiority of antegrade (ACP) or retrograde (RCP) cerebral perfusion has not been shown. We examined the early and late outcomes for ACP versus RCP in proximal (hemi-) arch replacement using deep hypothermic circulatory arrest (DHCA). Methods A retrospective analysis of a prospectively maintained database was performed for all patients undergoing elective and nonelective hemiarch replacement at a single referral institution from June 2005 to February 2013. Total arch cases were excluded to limit the analysis to shorter DHCA times and a more uniform patient population for whom clinical equipoise regarding ACP versus RCP exists. A total of 440 procedures were identified, with 360 (82%) using ACP and 80 (18%) using RCP. The endpoints included 30-day/in-hospital and late outcomes. A propensity score with 1:1 matching of 40 pre- and intraoperative variables was used to adjust for differences between the 2 groups. Results All 80 RCP patients were propensity matched to a cohort of 80 similar ACP patients. The pre- and intra-operative characteristics were not significantly different between the 2 groups after matching. No differences were found in 30-day/in-hospital mortality or morbidity outcomes. The only significant difference between the 2 groups was a shorter mean operative time in the RCP cohort (P = .01). No significant differences were noted in late survival (P = .90). Conclusions In proximal arch operations using DHCA, equivalent early and late outcomes can be achieved with RCP and ACP, although the mean operative time is significantly less with RCP, likely owing to avoidance of axillary cannulation. Questions remain regarding comparative outcomes with straight DHCA and lesser degrees of hypothermia. PMID:24908350
Ganapathi, Asvin M; Hanna, Jennifer M; Schechter, Matthew A; Englum, Brian R; Castleberry, Anthony W; Gaca, Jeffrey G; Hughes, G Chad
2014-12-01
The choice of cerebral perfusion strategy for aortic arch surgery has been debated, and the superiority of antegrade (ACP) or retrograde (RCP) cerebral perfusion has not been shown. We examined the early and late outcomes for ACP versus RCP in proximal (hemi-) arch replacement using deep hypothermic circulatory arrest (DHCA). A retrospective analysis of a prospectively maintained database was performed for all patients undergoing elective and nonelective hemiarch replacement at a single referral institution from June 2005 to February 2013. Total arch cases were excluded to limit the analysis to shorter DHCA times and a more uniform patient population for whom clinical equipoise regarding ACP versus RCP exists. A total of 440 procedures were identified, with 360 (82%) using ACP and 80 (18%) using RCP. The endpoints included 30-day/in-hospital and late outcomes. A propensity score with 1:1 matching of 40 pre- and intraoperative variables was used to adjust for differences between the 2 groups. All 80 RCP patients were propensity matched to a cohort of 80 similar ACP patients. The pre- and intraoperative characteristics were not significantly different between the 2 groups after matching. No differences were found in 30-day/in-hospital mortality or morbidity outcomes. The only significant difference between the 2 groups was a shorter mean operative time in the RCP cohort (P = .01). No significant differences were noted in late survival (P = .90). In proximal arch operations using DHCA, equivalent early and late outcomes can be achieved with RCP and ACP, although the mean operative time is significantly less with RCP, likely owing to avoidance of axillary cannulation. Questions remain regarding comparative outcomes with straight DHCA and lesser degrees of hypothermia. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
Evaluation of a disease management program for COPD using propensity matched control group
George, Pradeep Paul; Heng, Bee Hoon; Lim, Tow Keang; Abisheganaden, John; Ng, Alan Wei Keong; Lim, Fong Seng
2016-01-01
Background Disease management programs (DMPs) have proliferated recently as a means of improving the quality and efficiency of care for patients with chronic illness. These programs include education about disease, optimization of evidence-based medications, information and support from case managers, and institution of self-management principles. Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality in Singapore and worldwide. DMP aims to reduce mortality, hospitalizations, and average length of stay in such patients. This study assesses the outcomes of the DMP, comparing the propensity score matched DMP patients with controls. Methods DMP patients were compared with the controls, who were COPD patients fulfilling the DMP’s inclusion criteria but not included in the program. Control patients were identified from Operations Data Store (ODS) database. The outcomes of interest were average length of stay, number of days admitted to hospital per 100 person days, readmission, and mortality rates per person year. The risk of death and readmission was estimated using Cox, and competing risk regression respectively. Propensity score was estimated to identify the predictors of DMP enrolment. DMP patients and controls were matched on their propensity score. Results There were 170 matched DMP patients and control patients having 287 and 207 hospitalizations respectively. Program patient had lower mortality than the controls (0.12 vs. 0.27 per person year); cumulative 1-year survival was 91% among program patient and 76% among the control patients. Readmission, and hospital days per 100 person-days was higher for the program patients (0.36 vs. 0.17 per person year), and (2.19 vs. 1.88 per person year) respectively. Conclusions Participation in “DMP” was associated with lower all-cause mortality when compared to the controls. This survival gain in the program patients was paradoxically associated with an increase in readmission rate and
Evaluation of a disease management program for COPD using propensity matched control group.
George, Pradeep Paul; Heng, Bee Hoon; Lim, Tow Keang; Abisheganaden, John; Ng, Alan Wei Keong; Verma, Akash; Lim, Fong Seng
2016-07-01
Disease management programs (DMPs) have proliferated recently as a means of improving the quality and efficiency of care for patients with chronic illness. These programs include education about disease, optimization of evidence-based medications, information and support from case managers, and institution of self-management principles. Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality in Singapore and worldwide. DMP aims to reduce mortality, hospitalizations, and average length of stay in such patients. This study assesses the outcomes of the DMP, comparing the propensity score matched DMP patients with controls. DMP patients were compared with the controls, who were COPD patients fulfilling the DMP's inclusion criteria but not included in the program. Control patients were identified from Operations Data Store (ODS) database. The outcomes of interest were average length of stay, number of days admitted to hospital per 100 person days, readmission, and mortality rates per person year. The risk of death and readmission was estimated using Cox, and competing risk regression respectively. Propensity score was estimated to identify the predictors of DMP enrolment. DMP patients and controls were matched on their propensity score. There were 170 matched DMP patients and control patients having 287 and 207 hospitalizations respectively. Program patient had lower mortality than the controls (0.12 vs. 0.27 per person year); cumulative 1-year survival was 91% among program patient and 76% among the control patients. Readmission, and hospital days per 100 person-days was higher for the program patients (0.36 vs. 0.17 per person year), and (2.19 vs. 1.88 per person year) respectively. Participation in "DMP" was associated with lower all-cause mortality when compared to the controls. This survival gain in the program patients was paradoxically associated with an increase in readmission rate and total hospital days.
Schroeder, Krista; Jia, Haomiao; Smaldone, Arlene
Propensity score (PS) methods are increasingly being employed by researchers to reduce bias arising from confounder imbalance when using observational data to examine intervention effects. The purpose of this study was to examine PS theory and methodology and compare application of three PS methods (matching, stratification, weighting) to determine which best improves confounder balance. Baseline characteristics of a sample of 20,518 school-aged children with severe obesity (of whom 1,054 received an obesity intervention) were assessed prior to PS application. Three PS methods were then applied to the data to determine which showed the greatest improvement in confounder balance between the intervention and control group. The effect of each PS method on the outcome variable-body mass index percentile change at one year-was also examined. SAS 9.4 and Comprehensive Meta-analysis statistical software were used for analyses. Prior to PS adjustment, the intervention and control groups differed significantly on seven of 11 potential confounders. PS matching removed all differences. PS stratification and weighting both removed one difference but created two new differences. Sensitivity analyses did not change these results. Body mass index percentile at 1 year decreased in both groups. The size of the decrease was smaller in the intervention group, and the estimate of the decrease varied by PS method. Selection of a PS method should be guided by insight from statistical theory and simulation experiments, in addition to observed improvement in confounder balance. For this data set, PS matching worked best to correct confounder imbalance. Because each method varied in correcting confounder imbalance, we recommend that multiple PS methods be compared for ability to improve confounder balance before implementation in evaluating treatment effects in observational data.
Fletcher, Jeffrey J; Kade, Allison M; Sheehan, Kyle M; Wilson, Thomas J
2014-08-01
Mannitol has been shown to damage endothelial cells and activate coagulation pathways leading to intravascular thrombosis. Dehydration and hemagglutination have also been associated with mannitol use, although the risk of clinically evident venous thromboembolism (VTE) disease is not well-defined. The aim of this study was to compare the risk of VTE in critically ill neurological patients who received mannitol compared to only hypertonic saline. A case-cohort study design with propensity score matching was used to evaluate the risk of VTE among patients who received mannitol compared to those who received hypertonic saline alone. The odds of thrombosis were evaluated by the Cochran-Mantel-Haenszel method and conditional logistic regression was used to adjust for year of treatment. Ninety-one of 330 patients (27.6%; 95% confidence interval [CI] 23-33%) developed a VTE; however, the yearly proportion remained unchanged over the 8 year study period. Cumulative use of mannitol declined and use of hypertonic saline increased significantly. The odds of thrombosis for those exposed to mannitol compared to hypertonic saline alone was 1.11 (95% CI 0.65-1.73; p=0.75). This remained insignificant after adjusting for year of injury. In conclusion, despite a significant change in the pattern of osmotic therapy used at our institution, the proportion of patients with VTE remained unchanged. We found no evidence that mannitol use was associated with VTE compared to hypertonic saline alone. Copyright © 2014. Published by Elsevier Ltd.
Validation of the Australian Propensity for Angry Driving Scale (Aus-PADS).
Leal, Nerida L; Pachana, Nancy A
2009-09-01
The present study used a university sample to assess the test-retest reliability and validity of the Australian Propensity for Angry Driving Scale (Aus-PADS). The scale has stability over time, and convergent validity was established, as Aus-PADS scores correlated significantly with established anger and impulsivity measures. Discriminant validity was also established, as Aus-PADS scores did not correlate with Venturesomeness scores. The Aus-PADS has demonstrated criterion validity, as scores were correlated with behavioural measures, such as yelling at other drivers, gesturing at other drivers, and feeling angry but not doing anything. Aus-PADS scores reliably predicted the frequency of these behaviours over and above other study variables. No significant relationship between aggressive driving and crash involvement was observed. It was concluded that the Aus-PADS is a reliable and valid tool appropriate for use in Australian research, and that the potential relationship between aggressive driving and crash involvement warrants further investigation with a more representative (and diverse) driver sample.
Choi, Jae Woo; Park, Eun Cheol; Yoo, Ki Bong; Lee, Sang Gyu; Jang, Sung In; Kim, Tae Hyun
2015-09-10
Almost 97% of the Korean population is covered by National Health Insurance and are entitled to receive the same level of insurance benefits, regardless of how much each enrollee contributes to the system. However, the percentage of out-of-pocket payments is still high. This study examines whether the incurrence of high medical expenses affects household income. We use the Korea Welfare Panel and select 4,962 households to measure repeatedly over 5 years. Using propensity score matching, we set households with medical expenses of three times the annual average as "occurrence households" while "non-occurrence households" are those below the cut-off but with all other factors, such as income, held constant. We analyze whether the income of occurrence households differs significantly from the comparison group using a linear mixed effect model. After the occurrence of high medical expenditure, occurrence households (n = 825) had US$ 1,737 less income than non-occurrence households. In addition, the income of households (n = 200) that incurred high medical costs repeatedly for 2 years was US$ 3,598 lower than the non-occurrence group. Although it is important for the government to focus on medical assistance for households that have medical expense burdens, it needs to consider providing income indemnity insurance to protect them.
Kim, Dae-Hwan; Mak, Kwok-Kei
2016-01-01
This study examined the gender-specific associations between cohabitation with parents and stress using an econometric approach. A total of 13,565 (41.7% men and 58.3% women) Korean adults aged 20-59 years from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008 to 2011 were pooled. They reported their gender, age, marital status, education level, employment status, income, home ownership, and cohabitation status with their parents. The association of living with parents and stress, as well as the gender difference in the association, was investigated using propensity score matching and the average treatment effect on the treated. Adults with higher education and income, not owning a house, or living in larger cities were less likely to live with parents. Stress was associated with having children and participating in the labor market for both married men and women. Moreover, living with parents was a protective factor for stress among husbands, but a risk factor for wives in Korea. Gender differences existed in the association between cohabitation with parents and stress. Greater stress was related to cohabiting with parents and working for married women.
Graham, Amanda L; Papandonatos, George D; Erar, Bahar; Stanton, Cassandra A
2015-12-01
We estimated the causal effects of use of an online smoking cessation community on 30-day point prevalence abstinence at 3 months. Participants (N = 492) were adult current smokers in the enhanced Internet arm of The iQUITT Study, a randomized trial of Internet and telephone treatment for smoking cessation. All participants accessed a Web-based smoking-cessation program that included a large, established online community. Automated tracking metrics of passive (e.g., reading forum posts, viewing member profiles) and active (e.g., writing forum posts, sending private messages) community use were extracted from the site at 3 months. Self-selected community use defines the groups of interest: "None," "Passive," and "Both" (passive + active). Inverse probability of treatment weighting corrected for baseline imbalances on demographic, smoking, psychosocial, and medical history variables. Propensity weights estimated via generalized boosted models were used to calculate Average Treatment Effects (ATE) and Average Treatment effects on the Treated (ATT). Patterns of community use were: None = 198 (40.2%), Passive = 110 (22.4%), and Both = 184 (37.4%). ATE-weighted abstinence rates were: None = 4.2% (95% CI = 1.5-6.9); Passive = 15.1% (95% CI = 8.4-21.9); Both = 20.4% (95% CI = 13.9-26.8). ATT-weighted abstinence rates indicated even greater benefits of community use. Community users were more likely to quit smoking at 3 months than nonusers. The estimated benefit from use of online community resources was even larger among subjects with high propensity to use them. No differences in abstinence emerged between passive and passive/active users. Results suggest that lurking in online communities confers specific abstinence benefits. Implications of these findings for online cessation communities are discussed. (PsycINFO Database Record (c) 2015 APA, all rights reserved).
Pfeiffer, R M; Riedl, R
2015-08-15
We assess the asymptotic bias of estimates of exposure effects conditional on covariates when summary scores of confounders, instead of the confounders themselves, are used to analyze observational data. First, we study regression models for cohort data that are adjusted for summary scores. Second, we derive the asymptotic bias for case-control studies when cases and controls are matched on a summary score, and then analyzed either using conditional logistic regression or by unconditional logistic regression adjusted for the summary score. Two scores, the propensity score (PS) and the disease risk score (DRS) are studied in detail. For cohort analysis, when regression models are adjusted for the PS, the estimated conditional treatment effect is unbiased only for linear models, or at the null for non-linear models. Adjustment of cohort data for DRS yields unbiased estimates only for linear regression; all other estimates of exposure effects are biased. Matching cases and controls on DRS and analyzing them using conditional logistic regression yields unbiased estimates of exposure effect, whereas adjusting for the DRS in unconditional logistic regression yields biased estimates, even under the null hypothesis of no association. Matching cases and controls on the PS yield unbiased estimates only under the null for both conditional and unconditional logistic regression, adjusted for the PS. We study the bias for various confounding scenarios and compare our asymptotic results with those from simulations with limited sample sizes. To create realistic correlations among multiple confounders, we also based simulations on a real dataset. Copyright © 2015 John Wiley & Sons, Ltd.
Millett, Peter J; Espinoza, Chris; Horan, Marilee P; Ho, Charles P; Warth, Ryan J; Dornan, Grant J; Christoph Katthagen, J
2017-10-01
To evaluate the outcomes of two commonly used transosseous-equivalent (TOE) arthroscopic rotator cuff repair (RCR) techniques for full-thickness supraspinatus tendon tears (FTST) using a robust multi-predictor model. 155 shoulders in 151 patients (109 men, 42 women; mean age 59 ± 10 years) who underwent arthroscopic RCR of FTST, using either a knotted suture bridging (KSB) or a knotless tape bridging (KTB) TOE technique were included. ASES and SF-12 PCS scores assessed at a minimum of 2 years postoperatively were modeled using propensity score weighting in a multiple linear regression model. Patients able to return to the study center underwent a follow-up MRI for evaluation of rotator cuff integrity. The outcome data were available for 137 shoulders (88%; n = 35/41 KSB; n = 102/114 KTB). Seven patients (5.1%) that underwent revision rotator cuff surgery were considered failures. The median postoperative ASES score of the remaining 130 shoulders was 98 at a mean follow-up of 2.9 years (range 2.0-5.4 years). A higher preoperative baseline outcome score and a longer follow-up had a positive effect, whereas a previous RCR and workers' compensation claims (WCC) had a negative effect on final ASES or SF 12 PCS scores. The repair technique, age, gender and the number of anchors used for the RCR had no significant influence. Fifty-two patients returned for a follow-up MRI at a mean of 4.4 years postoperatively. Patients with a KSB RCR were significantly more likely to have an MRI-diagnosed full-thickness rotator cuff re-tear (p < 0.05). Excellent outcomes can be achieved at a minimum of 2 years following arthroscopic KSB or KTB TOE RCR of FTST. The preoperative baseline outcome score, a prior RCR, WCC and the length of follow-up significantly influenced the outcome scores. The repair technique did not affect the final functional outcomes, but patients with KTB TOE RCR were less likely to have a full-thickness rotator cuff re-tear. Level III, Retrospective
NASA Astrophysics Data System (ADS)
Haverland, Nicole A.; Skinner, Owen S.; Fellers, Ryan T.; Tariq, Areeba A.; Early, Bryan P.; LeDuc, Richard D.; Fornelli, Luca; Compton, Philip D.; Kelleher, Neil L.
2017-06-01
Fragmentation of intact proteins in the gas phase is influenced by amino acid composition, the mass and charge of precursor ions, higher order structure, and the dissociation technique used. The likelihood of fragmentation occurring between a pair of residues is referred to as the fragmentation propensity and is calculated by dividing the total number of assigned fragmentation events by the total number of possible fragmentation events for each residue pair. Here, we describe general fragmentation propensities when performing top-down mass spectrometry (TDMS) using denaturing or native electrospray ionization. A total of 5311 matched fragmentation sites were collected for 131 proteoforms that were analyzed over 165 experiments using native top-down mass spectrometry (nTDMS). These data were used to determine the fragmentation propensities for 399 residue pairs. In comparison to denatured top-down mass spectrometry (dTDMS), the fragmentation pathways occurring either N-terminal to proline or C-terminal to aspartic acid were even more enhanced in nTDMS compared with other residues. More generally, 257/399 (64%) of the fragmentation propensities were significantly altered ( P ≤ 0.05) when using nTDMS compared with dTDMS, and of these, 123 were altered by 2-fold or greater. The most notable enhancements of fragmentation propensities for TDMS in native versus denatured mode occurred (1) C-terminal to aspartic acid, (2) between phenylalanine and tryptophan (F|W), and (3) between tryptophan and alanine (W|A). The fragmentation propensities presented here will be of high value in the development of tailored scoring systems used in nTDMS of both intact proteins and protein complexes. [Figure not available: see fulltext.
Bhavnani, Sanjeev P; Giedrimiene, Dalia; Coleman, Craig I; Guertin, Danette; Azeem, Meena; Kluger, Jeffrey
2014-10-01
Inappropriate shocks (IASs) from implantable cardioverter defibrillators (ICDs) are associated with decreased quality of life, but whether they increase healthcare utilization and treatment costs is unknown. We sought to determine the impact of IASs on subsequent healthcare utilization and treatment costs. We conducted a case-control analysis of ICD patients at a single institution from 1997 to 2010 and who had ≥12 months of post-ICD implant follow-up. Cases included all patients experiencing an IAS during the first 12 months after implantation. Eligible control patients did not receive a shock of any kind during the 12 months after implantation. Propensity scores based on 36 covariates (area under curve = 0.78) were used to match cases to controls. We compared the rate (occurrences/person year [PY]) of healthcare utilization immediately following IAS to the end of the 12-month follow-up period to the rate in the no-shock group over 12 months of follow-up. We also compared 12-month postimplant treatment (outpatient clinic, emergency room, and hospitalization) costs in both groups. A total of 76 patients experiencing ≥1 IAS during the first 12 months after implant (contributing 48 PYs) were matched to 76 no-shock patients (contributing 76 PYs). Cardiovascular (CV)-related clinic visit and hospitalization rates were increased following an IAS compared to those not receiving a shock (4.0 vs 3.3 and 0.7 vs 0.5, respectively, P = 0.02 for both). CV-related emergency room visitation (0.15 vs 0.08) rates were also numerically higher following an IAS, but did not reach statistical significance (P = 0.26). Patients experiencing an IAS accrued greater treatment costs during the 12 months postimplant compared to no-shock patients ($13,973 ± $46,345 vs $6,790 ± $19,091, P = 0.001). Recipients of IAS utilize the healthcare system more frequently following an IAS than patients not experiencing a shock. This increased utilization results in higher costs of treating IAS
McLawhorn, Alexander S; Schairer, William W; Schwarzkopf, Ran; Halsey, David A; Iorio, Richard; Padgett, Douglas E
2017-12-06
For Medicare beneficiaries, hospital reimbursement for nonrevision hip arthroplasty is anchored to either diagnosis-related group code 469 or 470. Under alternative payment models, reimbursement for care episodes is not further risk-adjusted. This study's purpose was to compare outcomes of primary total hip arthroplasty (THA) vs conversion THA to explore the rationale for risk adjustment for conversion procedures. All primary and conversion THAs from 2007 to 2014, excluding acute hip fractures and cancer patients, were identified in the National Surgical Quality Improvement Program database. Conversion and primary THA patients were matched 1:1 using propensity scores, based on preoperative covariates. Multivariable logistic regressions evaluated associations between conversion THA and 30-day outcomes. A total of 2018 conversions were matched to 2018 primaries. There were no differences in preoperative covariates. Conversions had longer operative times (148 vs 95 minutes, P < .001), more transfusions (37% vs 17%, P < .001), and longer length of stay (4.4 vs 3.1 days, P < .001). Conversion THA had increased odds of complications (odds ratio [OR] 1.75; 95% confidence interval [CI] 1.37-2.24), deep infection (OR 4.21; 95% CI 1.72-10.28), discharge to inpatient care (OR 1.52; 95% CI 1.34-1.72), and death (OR 2.39; 95% CI 1.04-5.47). Readmission odds were similar. Compared with primary THA, conversion THA is associated with more complications, longer length of stay, and increased discharge to continued inpatient care, implying greater resource utilization for conversion patients. As reimbursement models shift toward bundled payment paradigms, conversion THA appears to be a procedure for which risk adjustment is appropriate. Copyright © 2017 Elsevier Inc. All rights reserved.
Spatial correlation of the dynamic propensity of a glass-forming liquid
NASA Astrophysics Data System (ADS)
Razul, M. Shajahan G.; Matharoo, Gurpreet S.; Poole, Peter H.
2011-06-01
We present computer simulation results on the dynamic propensity (as defined by Widmer-Cooper et al 2004 Phys. Rev. Lett. 93 135701) in a Kob-Andersen binary Lennard-Jones liquid system consisting of 8788 particles. We compute the spatial correlation function for the dynamic propensity as a function of both the reduced temperature T, and the time scale on which the particle displacements are measured. For T <= 0.6, we find that non-zero correlations occur at the largest length scale accessible in our system. We also show that a cluster-size analysis of particles with extremal values of the dynamic propensity, as well as 3D visualizations, reveal spatially correlated regions that approach the size of our system as T decreases, consistently with the behavior of the spatial correlation function. Next, we define and examine the 'coordination propensity', the isoconfigurational average of the coordination number of the minority B particles around the majority A particles. We show that a significant correlation exists between the spatial fluctuations of the dynamic and coordination propensities. In addition, we find non-zero correlations of the coordination propensity occurring at the largest length scale accessible in our system for all T in the range 0.466 < T < 1.0. We discuss the implications of these results for understanding the length scales of dynamical heterogeneity in glass-forming liquids.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Troeller, Almut; Department of Radiotherapy and Radiation Oncology, Ludwig-Maximilians-Universität, Munich; Yan, Di, E-mail: dyan@beaumont.edu
2015-02-01
Purpose: This study compared normal tissue complication probability (NTCP) modeling of chronic gastrointestinal toxicities following prostate cancer treatment for 2 treatment modalities. Possible factors causing discrepancies in optimal NTCP model parameters between 3-dimensional conformal radiation therapy (3D-CRT) and intensity modulated RT (IMRT) were analyzed and discussed, including the impact of patient characteristics, image guidance, toxicity scoring bias, and NTCP model limitations. Methods and Materials: Rectal wall dose-volume histograms of 1115 patients treated for prostate cancer under an adaptive radiation therapy protocol were used to model gastrointestinal toxicity grade ≥2 (according to Common Terminology Criteria for Adverse Events). A total ofmore » 457 patients were treated with 3D-CRT and 658 with IMRT. 3D-CRT patients were matched to IMRT patients based on various patient characteristics, using a propensity score–based algorithm. Parameters of the Lyman equivalent uniform dose and cut-off dose logistic regression NTCP models were estimated for the 2 matched treatment modalities and the combined group. Results: After they were matched, the 3D-CRT and IMRT groups contained 275 and 550 patients with a large discrepancy of 28.7% versus 7.8% toxicities, respectively (P<.001). For both NTCP models, optimal parameters found for the 3D-CRT groups did not fit the IMRT patients well and vice versa. Models developed for the combined data overestimated NTCP for the IMRT patients and underestimated NTCP for the 3D-CRT group. Conclusions: Our analysis did not reveal a single definitive cause for discrepancies of model parameters between 3D-CRT and IMRT. Patient characteristics and bias in toxicity scoring, as well as image guidance alone, are unlikely causes of the large discrepancy of toxicities. Whether the cause was inherent to the specific NTCP models used in this study needs to be verified by future investigations. Because IMRT is increasingly
High accuracy prediction of beta-turns and their types using propensities and multiple alignments.
Fuchs, Patrick F J; Alix, Alain J P
2005-06-01
We have developed a method that predicts both the presence and the type of beta-turns, using a straightforward approach based on propensities and multiple alignments. The propensities were calculated classically, but the way to use them for prediction was completely new: starting from a tetrapeptide sequence on which one wants to evaluate the presence of a beta-turn, the propensity for a given residue is modified by taking into account all the residues present in the multiple alignment at this position. The evaluation of a score is then done by weighting these propensities by the use of Position-specific score matrices generated by PSI-BLAST. The introduction of secondary structure information predicted by PSIPRED or SSPRO2 as well as taking into account the flanking residues around the tetrapeptide improved the accuracy greatly. This latter evaluated on a database of 426 reference proteins (previously used on other studies) by a sevenfold crossvalidation gave very good results with a Matthews Correlation Coefficient (MCC) of 0.42 and an overall prediction accuracy of 74.8%; this places our method among the best ones. A jackknife test was also done, which gave results within the same range. This shows that it is possible to reach neural networks accuracy with considerably less computional cost and complexity. Furthermore, propensities remain excellent descriptors of amino acid tendencies to belong to beta-turns, which can be useful for peptide or protein engineering and design. For beta-turn type prediction, we reached the best accuracy ever published in terms of MCC (except for the irregular type IV) in the range of 0.25-0.30 for types I, II, and I' and 0.13-0.15 for types VIII, II', and IV. To our knowledge, our method is the only one available on the Web that predicts types I' and II'. The accuracy evaluated on two larger databases of 547 and 823 proteins was not improved significantly. All of this was implemented into a Web server called COUDES (French acronym
Del Giglio, Mauro; Mikus, Elisa; Micari, Antonio; Calvi, Simone; Tripodi, Alberto; Campo, Gianluca; Maietti, Elisa; Castriota, Fausto; Cremonesi, Alberto
2018-01-01
Background Right anterior mini-thoracotomy (MIAVR) is a promising technique for aortic valve replacement. We aimed at comparing its outcomes with those obtained in a propensity-matched group of patients undergoing sternotomy at our two high-volume centers. Methods Main clinical and operative data of patients undergoing aortic valve replacement between January 2010 and May 2016 were retrospectively collected. A total of 678 patients were treated with a standard full sternotomy approach, while MIAVR was performed in 502. Propensity score matching identified 363 patients per each group. Results In-hospital mortality was not significantly different between the propensity-matched groups (1.7% in MIAVR patients vs. 2.2% in conventional sternotomy patients; P=0.79). No significant difference in the incidence of major post-operative complications was observed. Post-operative ventilation times (median 7, range 5–12 hours in MIAVR patients vs. median 7, range 5–12 in conventional sternotomy patients; P=0.72) were not significantly different between the two groups. Cardiopulmonary bypass time (61.0±21.0 vs. 65.9±24.7 min in conventional sternotomy group; P<0.01) and aortic cross-clamping time (48.3±16.7 vs. 53.2±19.6 min in full sternotomy group; P<0.01) were shorter in MIAVR group. EuroSCORE (OR 1.52, 95% CI, 1.12–2.06; P<0.01) was found to be the only independent predictor of intra-hospital mortality in the whole propensity-matched population. Conclusions Our experience shows that mini-access isolated aortic valve surgery is a reproducible, safe and effective procedure with similar outcomes and no longer operative times compared to conventional sternotomy. PMID:29707310
A Statistical Analysis of the PPII Propensity of Amino Acid Guests in Proline-Rich Peptides
Moradi, Mahmoud; Babin, Volodymyr; Sagui, Celeste; Roland, Christopher
2011-01-01
There has been considerable debate about the intrinsic PPII propensity of amino-acid residues in denatured polypeptides. Experimentally, the propensity scale is based on the behavior of guest amino-acid residues placed in the middle of polyproline hosts. We have used classical molecular dynamics simulations, with state-of-the-art force fields to carry out a comprehensive analysis of the conformational equilibria of the proline-based host oligopeptides with single guests. The tracked structural characteristics include the PPII content, the cis/trans isomerization of the prolyl bonds, the puckering of the pyrrolidine rings of the proline residues, and the secondary structural motifs. We find no evidence for an intrinsic PPII propensity in any of the guest amino acids other than proline. Instead, the PPII content as derived from experiments may be explained in terms of: 1), a local correlation between the dihedral angles of the guest amino acid and the proline residue immediately preceding it; and 2), a nonlocal correlation between the cis/trans states of the peptide bonds. In terms of the latter, we find that the presence of a guest (other than proline, tyrosine, or tryptophan) increases the trans content of most of the prolyl bonds, which results in an effective increase of the peptide PPII content. With respect to the local dihedral correlations, we find that these are well described in terms of the so-called odds-ratio statistic. Expressed in terms of free energy language, the PPII content based on the odds-ratio of the relevant residues correlate well with the experimentally measured PPII content. PMID:21320454
Lane-changing model with dynamic consideration of driver's propensity
NASA Astrophysics Data System (ADS)
Wang, Xiaoyuan; Wang, Jianqiang; Zhang, Jinglei; Ban, Xuegang Jeff
2015-07-01
Lane-changing is the driver's selection result of the satisfaction degree in different lane driving conditions. There are many different factors influencing lane-changing behavior, such as diversity, randomicity and difficulty of measurement. So it is hard to accurately reflect the uncertainty of drivers' lane-changing behavior. As a result, the research of lane-changing models is behind that of car-following models. Driver's propensity is her/his emotion state or the corresponding preference of a decision or action toward the real objective traffic situations under the influence of various dynamic factors. It represents the psychological characteristics of the driver in the process of vehicle operation and movement. It is an important factor to influence lane-changing. In this paper, dynamic recognition of driver's propensity is considered during simulation based on its time-varying discipline and the analysis of the driver's psycho-physic characteristics. The Analytic Hierarchy Process (AHP) method is used to quantify the hierarchy of driver's dynamic lane-changing decision-making process, especially the influence of the propensity. The model is validated using real data. Test results show that the developed lane-changing model with the dynamic consideration of a driver's time-varying propensity and the AHP method are feasible and with improved accuracy.
Ahmed, Ali; Husain, Ahsan; Love, Thomas E.; Gambassi, Giovanni; Dell'Italia, Louis J.; Francis, Gary S.; Gheorghiade, Mihai; Allman, Richard M.; Meleth, Sreelatha; Bourge, Robert C.
2008-01-01
Aims Non-potassium-sparing diuretics are commonly used in heart failure (HF). They activate the neurohormonal system, and are potentially harmful. Yet, the long-term effects of chronic diuretic use in HF are largely unknown. We retrospectively analysed the Digitalis Investigation Group (DIG) data to determine the effects of diuretics on HF outcomes. Methods and results Propensity scores for diuretic use were calculated for each of the 7788 DIG participants using a non-parsimonious multivariable logistic regression model, and were used to match 1391 (81%) no-diuretic patients with 1391 diuretic patients. Effects of diuretics on mortality and hospitalization at 40 months of median follow-up were assessed using matched Cox regression models. All-cause mortality was 21% for no-diuretic patients and 29% for diuretic patients [hazard ratio (HR) 1.31; 95% confidence interval (CI) 1.11−1.55; P = 0.002]. HF hospitalizations occurred in 18% of no-diuretic patients and 23% of diuretic patients (HR 1.37; 95% CI 1.13−1.65; P = 0.001). Conclusion Chronic diuretic use was associated with increased long-term mortality and hospitalizations in a wide spectrum of ambulatory chronic systolic and diastolic HF patients. The findings of the current study challenge the wisdom of routine chronic use of diuretics in HF patients who are asymptomatic or minimally symptomatic without fluid retention, and are on complete neurohormonal blockade. These findings, based on a non-randomized design, need to be further studied in randomized trials. PMID:16709595
Witusik, Andrzej; Mokros, Łukasz; Kuna, Piotr; Nowakowska-Domagała, Katarzyna; Antczak, Adam; Pietras, Tadeusz
2018-06-06
BACKGROUND Stress and psychological factors can induce dyspnea in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to assess selected elements of the clinical presentation of COPD in the context of the severity of type A pattern of behavior, impulsiveness, and tendency for empathy. MATERIAL AND METHODS This was a cross-sectional study. The study group consisted of 179 men with COPD and the control group consisted of 31 healthy male smokers. In all patients, the number of infectious exacerbations over the past year, the result on the dyspnea scale (MRC), and the FEV1-to- predicted FEV1 ratio was assessed. The A pattern of behavior was measured using the Type A scale. To measure impulsivity, risk propensity, and empathy, the IVE impulsivity questionnaire was used. RESULTS An increase in the number of infectious exacerbations was associated with an increased score on the Type A scale, an increase in risk propensity, and a decrease in impulsivity score. Increased severity of dyspnea was associated with an increase in Type A behavior pattern score and an increase in the risk propensity score. CONCLUSIONS Type A behavior pattern and risk propensity are independent predictors of the number of infections in the last year and of the subjective severity of dyspnea among men with COPD and healthy male smokers.
Hamada, Takeomi; Nanashima, Atsushi; Yano, Koichi; Sumida, Yorihisa; Hiyoshi, Masahide; Imamura, Naoya; Tobinaga, Shuichi; Tsuchimochi, Yuki; Takeno, Shinsuke; Fujii, Yoshiro; Nagayasu, Takeshi
2017-09-01
The VIO soft-coagulation system (VIO) with a monopolar electrode is a novel hemostatic device that provides hemostasis by superficial contact at the bleeding site without carbonization. Because heat injury remains a concern, surgical records and postoperative liver dysfunction were retrospectively evaluated in a cohort study. Between September 2010 and March 2016, 322 patients underwent hepatectomy in which hemostatic devices were used at two institutions. Surgical results with use of VIO at one institute (VIO group) were compared with those without use of VIO at a second institute (control group), and propensity analysis was performed. In limited resection and segmentectomy or sectionectomy performed in the VIO group, the prevalence of liver cirrhosis was significantly higher and the operation time was significantly longer in comparison with the control group (p < 0.05). In all hepatectomies, postoperative levels of total bilirubin and aspartate or alanine transaminase tended to be increased and prothrombin activity tended to be lower in the VIO group in comparison with the control group (p < 0.05). The prevalence of hepatic failure in the VIO group was significantly higher in comparison with that in the control group (p < 0.05). In cases of segmentectomy or sectionectomy, blood loss was significantly increased in the VIO group in comparison with that in the control group (p < 0.05) Propensity score matching showed that although the surgical records and outcomes were not significantly different between the groups, postoperative liver dysfunction was significant in the VIO group in comparison with the control group (p < 0.05). Mild postoperative hepatic thermal injury with VIO was confirmed, and therefore, surgeons should take care when using the VIO system to make frequent wide resected cuts on the surface of the liver. Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.
Boveda, Serge; Providência, Rui; Defaye, Pascal; Pavin, Dominique; Cebron, Jean-Pierre; Anselme, Frederic; Halimi, Franck; Khoueiry, Ziad; Combes, Nicolas; Combes, Stephane; Jacob, Sophie; Albenque, Jean-Paul; Sousa, Pedro
2016-11-01
Recent data show no benefit of additional ablation beyond pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF). Evidence suggests that radiofrequency energy (RF) and cryoballoon (CRYO) have comparable efficacy for PVI. We aimed to assess the outcomes after a single catheter ablation procedure, comparing PVI using CRYO vs. RF ablation for PVI plus additional ablation in a cohort of patients with persistent AF. In this prospective multicenter propensity score-matched comparison, 59 consecutive patients undergoing CRYO ablation of persistent AF were matched to 59 patients treated with RF from November 2010 to June 2012. During a mean follow-up of 15.6 ± 11.5 months, 43.2 % of patients presented atrial arrhythmia relapse after a blanking period of 3 months, which was comparable between the two groups (40.7 % in CRYO vs. 45.8 % in RF, Log rank P = 0.14; HR = 0.67, 95 %CI 0.38-1.16, P = 0.15), despite the fact that 52.5 % of RF patients add additional complex fractionated atrial electrogram ablation, as well as left atrial linear ablation in over two-thirds (roof line in 67.8 % and mitral isthmus in 32.2 %). On multivariate Cox regression, only AF duration in years (HR = 1.10, 95 %CI 1.01-1.10, P = 0.04) was a predictor of relapse. Patients undergoing RF ablation presented a numerically, but non-significantly, lower complication rate (6.8 vs 10.2 %, P = 0.51). In our multicenter experience, freedom from atrial arrhythmias was comparable among matched patients treated with CRYO and RF, despite non-significant trends in favor of RF in terms of complications, at the cost of longer procedure times.
Gillespie, Iain A; Floege, Jürgen; Gioni, Ioanna; Drüeke, Tilman B; de Francisco, Angel L; Anker, Stefan D; Kubo, Yumi; Wheeler, David C; Froissart, Marc
2015-07-01
The generalisability of randomised controlled trials (RCTs) may be limited by restrictive entry criteria or by their experimental nature. Observational research can provide complementary findings but is prone to bias. Employing propensity score matching, to reduce such bias, we compared the real-life effect of cinacalcet use on all-cause mortality (ACM) with findings from the Evaluation of Cinacalcet Therapy to Lower Cardiovascular Events (EVOLVE) RCT in chronic haemodialysis patients. Incident adult haemodialysis patients receiving cinacalcet, recruited in a prospective observational cohort from 2007-2009 (AROii; n = 10,488), were matched to non-exposed patients regardless of future exposure status. The effect of treatment crossover was investigated with inverse probability of censoring weighted and lag-censored analyses. EVOLVE ACM data were analysed largely as described for the primary composite endpoint. AROii patients receiving cinacalcet (n = 532) were matched to 1790 non-exposed patients. The treatment effect of cinacalcet on ACM in the main AROii analysis (hazard ratio 1.03 [95% confidence interval (CI) 0.78-1.35]) was closer to the null than for the Intention to Treat (ITT) analysis of EVOLVE (0.94 [95%CI 0.85-1.04]). Adjusting for non-persistence by 0- and 6-month lag-censoring and by inverse probability of censoring weight, the hazard ratios in AROii (0.76 [95%CI 0.51-1.15], 0.84 [95%CI 0.60-1.18] and 0.79 [95%CI 0.56-1.11], respectively) were comparable with those of EVOLVE (0.82 [95%CI 0.67-1.01], 0.83 [95%CI 0.73-0.96] and 0.87 [95%CI 0.71-1.06], respectively). Correcting for treatment crossover, we observed results in the 'real-life' setting of the AROii observational cohort that closely mirrored the results of the EVOLVE RCT. Persistence-corrected analyses revealed a trend towards reduced ACM in haemodialysis patients receiving cinacalcet therapy. Copyright © 2015 John Wiley & Sons, Ltd.
Adverse Childhood Experiences and Criminal Propensity Among Intimate Partner Violence Offenders.
Hilton, N Zoe; Ham, Elke; Green, Michelle M
2016-10-01
Adverse childhood experiences (ACEs), defined as exposure to abuse and adverse household events, are prevalent among certain offenders including those who commit intimate partner violence (IPV). However, it is not clear how ACEs relate to criminal propensity among IPV offenders, who have been shown to exhibit less antisociality and institutional violence than other offenders. We compared 99 male offenders with a current or previous offense of IPV with 233 non-IPV violent offenders and 103 nonviolent offenders undergoing institutional forensic assessment. This convenience sample allowed for use of extensive psychosocial records as well as study of institutional violence. IPV offenders had the highest mean ACE score and more extensive criminal propensity on some measures (violent and nonviolent criminal history and psychopathy) than both other groups. ACEs were associated with most measures of criminal propensity in the whole sample but with only one (actuarial risk of violent recidivism) in the subsample of IPV offenders. Finding that ACEs are prevalent among IPV offenders even in this sample with extensive mental illness demonstrates the robustness of this phenomenon. IPV offenders, though, are similar to other violent offenders in this respect, and there is insufficient evidence that ACEs represent a criminogenic need among IPV offenders specifically. Further research could draw from the batterer typology literature and attend to IPV offenders' broader criminal careers.
Goodin, Douglas S.; Jones, Jason; Li, David; Traboulsee, Anthony; Reder, Anthony T.; Beckmann, Karola; Konieczny, Andreas; Knappertz, Volker
2011-01-01
Context Establishing the long-term benefit of therapy in chronic diseases has been challenging. Long-term studies require non-randomized designs and, thus, are often confounded by biases. For example, although disease-modifying therapy in MS has a convincing benefit on several short-term outcome-measures in randomized trials, its impact on long-term function remains uncertain. Objective Data from the 16-year Long-Term Follow-up study of interferon-beta-1b is used to assess the relationship between drug-exposure and long-term disability in MS patients. Design/Setting To mitigate the bias of outcome-dependent exposure variation in non-randomized long-term studies, drug-exposure was measured as the medication-possession-ratio, adjusted up or down according to multiple different weighting-schemes based on MS severity and MS duration at treatment initiation. A recursive-partitioning algorithm assessed whether exposure (using any weighing scheme) affected long-term outcome. The optimal cut-point that was used to define “high” or “low” exposure-groups was chosen by the algorithm. Subsequent to verification of an exposure-impact that included all predictor variables, the two groups were compared using a weighted propensity-stratified analysis in order to mitigate any treatment-selection bias that may have been present. Finally, multiple sensitivity-analyses were undertaken using different definitions of long-term outcome and different assumptions about the data. Main Outcome Measure Long-Term Disability. Results In these analyses, the same weighting-scheme was consistently selected by the recursive-partitioning algorithm. This scheme reduced (down-weighted) the effectiveness of drug exposure as either disease duration or disability at treatment-onset increased. Applying this scheme and using propensity-stratification to further mitigate bias, high-exposure had a consistently better clinical outcome compared to low-exposure (Cox proportional hazard ratio = 0.30
ERIC Educational Resources Information Center
Köhler, Carmen; Pohl, Steffi; Carstensen, Claus H.
2015-01-01
When competence tests are administered, subjects frequently omit items. These missing responses pose a threat to correctly estimating the proficiency level. Newer model-based approaches aim to take nonignorable missing data processes into account by incorporating a latent missing propensity into the measurement model. Two assumptions are typically…
Liu, Kuan-Liang; Ye, Ling-Long; Chou, Shing-Hsien; Tung, Ying-Chang; Lin, Yu-Sheng; Wu, Lung-Sheng; Lin, Chia-Pin; Shia, Ben-Chang; Chu, Pao-Hsien
2016-01-01
Erectile dysfunction (ED) has been regarded a marker of cardiovascular diseases. Nevertheless, the association between ED and incident atrial fibrillation (AF) remains unknown. To determine the association between ED and incident AF. This population-based cohort study was conducted using the National Health Insurance Research Database in Taiwan. In total, 6,273 of patients with ED without a prior diagnosis of AF were enrolled from January 1, 2001 through December 31, 2009, and a propensity-score matching method was used to identify 3,516 patients in the ED and control groups. Newly incident AF at follow-up was recorded as the end point. The mean age of the study population was 40.0 ± 17.1 years, and the follow-up period was 8.0 ± 0.5 years. Compared with the control group, patients with ED were older and had more of the following comorbidities: D'Hoore Charlson Comorbidity Index, hypertension, congestive heart failure, diabetes mellitus, dyslipidemia, chronic kidney disease, coronary artery disease, stroke, chronic lung disease, major depression disorder, obstructive sleep apnea, and hyperthyroidism. After adjusting for confounders, the ED group was not associated with more incident AF compared with the control group (hazard ratio = 1.031, 95% confidence interval = 0.674-1.578, P =.888). In these patients, ED of an organic origin was associated with a trend of having AF more often compared with ED of a psychosexual type (P =.272 by log-rank test). Although ED is known as a predictor of atherosclerotic cardiovascular diseases, it is not independently associated with incident AF in men. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
Lu, Na; Misra, Devyani; Neogi, Tuhina; Choi, Hyon K.; Zhang, Yuqing
2015-01-01
Background We sought to replicate recent findings that total knee arthroplasty (TKA) or total hip arthroplasty (THA) surgery substantially reduces the risk of serious cardiovascular events among osteoarthritis patients in a UK general population. Methods We conducted a time-stratified propensity score-matched cohort study for the outcome of myocardial infarction (MI). The study population included individuals aged ≥50 years who had a Readcode diagnosis of knee osteoarthritis (to evaluate TKA) or hip osteoarthritis (to evaluate THA) between January 2000 and December 2012. Results Among 13,849 patients who underwent TKA and 13,849 matched non-TKA controls 306 and 286 developed MI during the follow-up, respectively. During the first postoperative month, the risk of MI was substantially increased among TKA group compared with non-TKA group (hazard ratio 8.75; 95% CI, 3.11–24.62), and then gradually declined during the subsequent follow-up. The HR of the entire follow-up was 0.98 (95% CI, 0.82–1.18). The corresponding HRs for THA (n=6,063) compared with non-THA were 4.33 (95% CI, 1.24–15.21) and 0.87 (95% CI, 0.66–1.15), respectively. Using venous thromboembolism as a positive control outcome, both the first month and overall HRs of MI were substantially increased for TKA and for THA, respectively. Conclusion These findings provide the first general population-based evidence that TKA and THA among osteoarthritis patients are associated with a substantially increased risk of MI during the immediate postoperative period. However, its overall long-term impact was null, unlike the risk of venous thromboembolism that remained years after the procedure. PMID:26331443
Thibodeau, Michel A; Welch, Patrick G; Sareen, Jitender; Asmundson, Gordon J G
2013-10-01
Research suggests that suicidal behavior in individuals with anxiety disorders is attributable to co-occurring risk factors, such as depression. We argue that these conclusions are founded primarily in statistical adjustments that may obscure independent associations. We explored independent associations between specific anxiety disorders and suicide attempts and ideation by means of propensity score matching, a process that simulates a case-control study by creating matched groups that differ in group status (e.g., diagnosis of a specific anxiety disorder) but that are statistically equivalent on observed covariates. We made use of the National Comorbidity Survey Replication (NCS-R) and the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), which include a total of 43,935 adults. Diagnoses included agoraphobia without panic disorder, generalized anxiety disorder, panic disorder with or without agoraphobia, posttraumatic stress disorder, social anxiety disorder, and specific phobia. Each anxiety disorder was (95% confidence intervals) associated with increased odds of lifetime suicide attempts (odds ratios 3.57-6.64 [NCS-R], 3.03-7.00 [NESARC]) and suicidal ideation (odds ratios 2.62-4.87 [NCS-R], 3.34-10.57 [NESARC]). Odds ratios for each disorder remained statistically significant after matching on diagnostic status of dysthymia, major depressive disorder, alcohol abuse/dependence, substance abuse/dependence, bipolar disorder I, bipolar disorder II, all other anxiety disorders, and on sociodemographic variables. This is the first report to present evidence that each anxiety disorder is associated with suicide ideation and suicide attempts beyond the effects of co-occurring mental disorders. These findings warrant consideration in assessment, intervention, and related policies. © 2013 Wiley Periodicals, Inc.
Wang, Qin; Hu, Ke-Jie; Ren, Ye-Ping; Dong, Jie; Han, Qing-Feng; Zhu, Tong-Ying; Chen, Jiang-Hua; Zhao, Hui-Ping; Chen, Meng-Hua; Xu, Rong; Wang, Yue; Hao, Chuan-Ming; Zhang, Xiao-Hui; Wang, Mei; Tian, Na; Wang, Hai-Yan
2016-01-01
♦ Research indicates that the socioeconomic status (SES) of individuals and the area where they live are related to initial peritonitis and outcomes in peritoneal dialysis (PD). We conducted a retrospective, multi-center cohort study in China to examine these associations. ♦ Data on 2,171 PD patients were collected from 7 centers, including baseline demographic, socioeconomic, and laboratory data. We explored the potential risk factors for initial peritonitis and outcomes using univariate Cox regression and unadjusted binary logistic regression. Then, we used propensity score matching to balance statistically significant risk factors for initial peritonitis and outcomes, and Kaplan-Meier survival analysis to compare differences in peritonitis-free rates between different groups of participants after matching. ♦ A total of 563 (25.9%) initial episodes of peritonitis occurred during the study period. The Kaplan-Meier peritonitis-free rate curve showed high-income patients had a significantly lower risk than low-income patients (p = 0.007) after matching for age, hemoglobin, albumin, and regional SES and PD center. The risk of treatment failure was significantly lower in the high-income than the low-income group after matching for the organism causing peritonitis and PD center: odds ratio (OR) = 0.27 (0.09 - 0.80, p = 0.018). Regional SES and education were not associated with initial peritonitis and outcomes. ♦ Our study demonstrates low individual income is a risk factor for the initial onset of peritonitis and treatment failure after initial peritonitis. Copyright © 2016 International Society for Peritoneal Dialysis.
A statistical analysis of the PPII propensity of amino acid guests in proline-rich peptides.
Moradi, Mahmoud; Babin, Volodymyr; Sagui, Celeste; Roland, Christopher
2011-02-16
There has been considerable debate about the intrinsic PPII propensity of amino-acid residues in denatured polypeptides. Experimentally, the propensity scale is based on the behavior of guest amino-acid residues placed in the middle of polyproline hosts. We have used classical molecular dynamics simulations, with state-of-the-art force fields to carry out a comprehensive analysis of the conformational equilibria of the proline-based host oligopeptides with single guests. The tracked structural characteristics include the PPII content, the cis/trans isomerization of the prolyl bonds, the puckering of the pyrrolidine rings of the proline residues, and the secondary structural motifs. We find no evidence for an intrinsic PPII propensity in any of the guest amino acids other than proline. Instead, the PPII content as derived from experiments may be explained in terms of: 1), a local correlation between the dihedral angles of the guest amino acid and the proline residue immediately preceding it; and 2), a nonlocal correlation between the cis/trans states of the peptide bonds. In terms of the latter, we find that the presence of a guest (other than proline, tyrosine, or tryptophan) increases the trans content of most of the prolyl bonds, which results in an effective increase of the peptide PPII content. With respect to the local dihedral correlations, we find that these are well described in terms of the so-called odds-ratio statistic. Expressed in terms of free energy language, the PPII content based on the odds-ratio of the relevant residues correlate well with the experimentally measured PPII content. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.