Journal ArticleDOI
Adjustments for Center in Multicenter Studies: An Overview
Reads0
Chats0
TLDR
The inattention of published studies to departures from the assumption behind most statistical methods, the independence of observations, is overlooked, and investigators need to identify centers, incorporate the concept of centers into their designs, estimate the design effect, and adjust confidence intervals and P values appropriately.Abstract:
Increasingly, investigators rely on multicenter or multigroup studies to demonstrate effectiveness and generalizability. Authors too often overlook the analytic challenges in these study designs: the correlation of outcomes and exposures among patients within centers, confounding of associations by center, and effect modification of treatment or exposure across center. Correlation or clustering, resulting from the similarity of outcomes among patients within a center, requires an adjustment to confidence intervals and P values, especially in observational studies and in randomized multicenter studies in which treatment is allocated by center rather than by individual patient. Multicenter designs also warrant testing and adjustment for the potential bias of confounding by center, and for the presence of effect modification or interaction by center. This paper uses examples from the recent biomedical literature to highlight the issues and analytic options.read more
Citations
More filters
Journal ArticleDOI
Bevacizumab Beyond First Progression Is Associated With Prolonged Overall Survival in Metastatic Colorectal Cancer: Results From a Large Observational Cohort Study (BRiTE)
TL;DR: Results from a large, prospective, observational study suggest that continued vascular endothelial growth factor inhibition with bevacizumab beyond initial PD could play an important role improving the overall success of therapy for patients who have mCRC.
Journal ArticleDOI
Depression, anxiety and somatization in primary care: syndrome overlap and functional impairment
Bernd Löwe,Robert L. Spitzer,Janet B. W. Williams,Monika Mussell,Dieter Schellberg,Kurt Kroenke,Kurt Kroenke +6 more
TL;DR: A potential consideration for future diagnostic classification would be to describe basic diagnostic criteria for a single overarching disorder and to optionally code additional diagnostic features that allow a more detailed classification into specific depressive, anxiety and somatoform subtypes.
Journal ArticleDOI
The timing of specialist evaluation in chronic kidney disease and mortality.
Kraig S. Kinchen,John H. Sadler,Nancy E. Fink,Ron Brookmeyer,Michael J. Klag,Andrew S. Levey,Neil R. Powe +6 more
TL;DR: The CHOICE Study examined the choices that patients and providers make in initiation and maintenance of renal replacement therapy, particularly the choice of hemodialysis versus peritoneal dialysis and the effect of late evaluation on mortality.
Journal ArticleDOI
Generalisability in economic evaluation studies in healthcare: a review and case studies.
Mark Sculpher,Pang Fs,Andrea Manca,Michael Drummond,Su Golder,Urdahl H,Linda Davies,Alison Eastwood +7 more
TL;DR: The review of applied economic studies based on decision analytic models showed that few studies were explicit about their target decision-maker(s)/jurisdictions, and regression-based methods are likely to offer a systematic approach to quantifying variability in patient-level data.
Journal Article
Multicentre, cluster-randomized clinical trial of algorithms for critical-care enteral and parenteral therapy (ACCEPT)
TL;DR: Implementation of evidence-based recommendations improved the provision of nutritional support and was associated with improved clinical outcomes.
References
More filters
Journal ArticleDOI
A simulation study of the number of events per variable in logistic regression analysis.
Peter Peduzzi,John Concato,John Concato,Elizabeth Kemper,Elizabeth Kemper,Theodore R. Holford,Alvan R. Feinstein,Alvan R. Feinstein +7 more
TL;DR: Findings indicate that low EPV can lead to major problems, and the regression coefficients were biased in both positive and negative directions, and paradoxical associations (significance in the wrong direction) were increased.
Book
Statistical Methods in Cancer Research
TL;DR: Statistical methods in cancer research as mentioned in this paper, Statistical Methods in Cancer Research, Statistical methods in Cancer research, Statistical methods for cancer research, کتابخانه مرکزی دانشگاه علوم پزش
Book
Multilevel Statistical Models
TL;DR: In this article, the authors present a general classification notation for multilevel models and a discussion of the general structure and maximum likelihood estimation for a multi-level model, as well as the adequacy of Ordinary Least Squares estimates.
Journal Article
Statistical methods in cancer research. Volume I - The analysis of case-control studies.
N. E. Breslow,N. E. Day +1 more
Journal ArticleDOI
Statistical methods in cancer research
Related Papers (5)
Design and Analysis of Cluster Randomization Trials in Health Research
Allan Donner,Neil Klar +1 more
Regression analysis of multivariate incomplete failure time data by modeling marginal distributions
L. J. Wei,Danyu Lin,L. Weissfeld +2 more