Presented, in part, at the Meeting of the Eastern North American Region (ENAR) of the International Biometric Society, 28–31 March 2004, Pittsburgh, PA, U.S.A.
Bias reduction in effectiveness analyses of longitudinal ordinal doses with a mixed-effects propensity adjustment†
Article first published online: 12 DEC 2005
Copyright © 2005 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 26, Issue 1, pages 110–123, 15 January 2007
How to Cite
Leon, A. C., Hedeker, D. and Teres, J. J. (2007), Bias reduction in effectiveness analyses of longitudinal ordinal doses with a mixed-effects propensity adjustment. Statist. Med., 26: 110–123. doi: 10.1002/sim.2458
- Issue published online: 29 NOV 2006
- Article first published online: 12 DEC 2005
- Manuscript Accepted: 17 OCT 2005
- Manuscript Received: 23 DEC 2004
- NIH. Grant Numbers: MH60447, MH68638
- treatment effectiveness;
- propensity adjustment;
- longitudinal study;
- observational study;
A mixed-effects propensity adjustment is described that can reduce bias in longitudinal studies involving non-equivalent comparison groups. There are two stages in this data analytic strategy. First, a model of propensity for treatment intensity examines variables that distinguish among subjects who receive various ordered doses of treatment across time using mixed-effects ordinal logistic regression. Second, the effectiveness model examines multiple times until recurrence to compare the ordered doses using a mixed-effects grouped-time survival model. Effectiveness analyses are initially stratified by propensity quintile. Then the quintile-specific results are pooled, assuming that there is not a propensity × treatment interaction. A Monte Carlo simulation study compares bias reduction in fully specified propensity model relative to misspecified models. In addition, type I error rate and statistical power are examined. The approach is illustrated by applying it to a longitudinal, observational study of maintenance treatment of major depression. Copyright © 2005 John Wiley & Sons, Ltd.