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Augmented generalized estimating equations for improving efficiency and validity of estimation in cluster randomized trials by leveraging cluster‐level and individual‐level covariates
Author(s) -
Stephens Alisa J.,
Tchetgen Tchetgen Eric J.,
Gruttola Victor De
Publication year - 2012
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4471
Subject(s) - covariate , estimator , randomized controlled trial , statistics , cluster (spacecraft) , variance (accounting) , cluster randomised controlled trial , estimating equations , generalized estimating equation , econometrics , computer science , mathematics , medicine , surgery , accounting , business , programming language
Recent methodological advances in covariate adjustment in randomized clinical trials have used semiparametric theory to improve efficiency of inferences by incorporating baseline covariates; these methods have focused on independent outcomes. We modify one of these approaches, augmentation of standard estimators, for use within cluster randomized trials in which treatments are assigned to groups of individuals, thereby inducing correlation. We demonstrate the potential for imbalance correction and efficiency improvement through consideration of both cluster‐level covariates and individual‐level covariates. To improve small‐sample estimation, we consider several variance adjustments. We evaluate this approach for continuous and binary outcomes through simulation and apply it to data from a cluster randomized trial of a community behavioral intervention related to HIV prevention in Tanzania. Copyright © 2012 John Wiley & Sons, Ltd.