Comparison of adaptive treatment strategies based on longitudinal outcomes in sequential multiple assignment randomized trials.

TitleComparison of adaptive treatment strategies based on longitudinal outcomes in sequential multiple assignment randomized trials.
Publication TypeJournal Article
Year of Publication2017
AuthorsLi, Zhiguo
JournalStat Med
Volume36
Issue3
Pagination403-415
Date Published2017 02 10
ISSN1097-0258
KeywordsAntipsychotic Agents, Data Interpretation, Statistical, Humans, Linear Models, Longitudinal Studies, Models, Statistical, Randomized Controlled Trials as Topic, Regression Analysis, Schizophrenia, Statistics as Topic, Treatment Outcome
Abstract

In sequential multiple assignment randomized trials, longitudinal outcomes may be the most important outcomes of interest because this type of trials is usually conducted in areas of chronic diseases or conditions. We propose to use a weighted generalized estimating equation (GEE) approach to analyzing data from such type of trials for comparing two adaptive treatment strategies based on generalized linear models. Although the randomization probabilities are known, we consider estimated weights in which the randomization probabilities are replaced by their empirical estimates and prove that the resulting weighted GEE estimator is more efficient than the estimators with true weights. The variance of the weighted GEE estimator is estimated by an empirical sandwich estimator. The time variable in the model can be linear, piecewise linear, or more complicated forms. This provides more flexibility that is important because, in the adaptive treatment setting, the treatment changes over time and, hence, a single linear trend over the whole period of study may not be practical. Simulation results show that the weighted GEE estimators of regression coefficients are consistent regardless of the specification of the correlation structure of the longitudinal outcomes. The weighted GEE method is then applied in analyzing data from the Clinical Antipsychotic Trials of Intervention Effectiveness. Copyright © 2016 John Wiley & Sons, Ltd.

DOI10.1002/sim.7136
Alternate JournalStat Med
Original PublicationComparison of adaptive treatment strategies based on longitudinal outcomes in sequential multiple assignment randomized trials.
PubMed ID27646957
PubMed Central IDPMC5209271
Grant ListP01 CA142538 / CA / NCI NIH HHS / United States