A0330
Title: Transporting randomized trial results to estimate counterfactual survival functions in the target populations
Authors: Zhiqiang Cao - Shenzhen Technology University (China) [presenting]
Abstract: When the distributions of treatment effect modifiers differ between a randomized trial and an external target population, the sample average treatment effect in the trial may be substantially different from the target population average treatment. Despite the increasingly rich literature on transportability, little attention has been devoted to methods for transporting trial results to estimate counterfactual survival functions in target populations when the primary outcome is time to event and subject to right censoring. Doubly robust estimators are studied to estimate counterfactual survival functions and the target average survival treatment effect in the target population, and their respective approximate variance estimators are provided. The focus is on a common scenario where the target population information is observed only through a complex survey and elucidates how the survey weights can be incorporated into each estimator considered. Simulation studies are conducted to examine the finite-sample performances of the proposed estimators in terms of bias, efficiency and coverage under both correct and incorrect model specifications. Finally, the proposed method is applied to assess the transportability of the results in the action to control cardiovascular risk in diabetes blood pressure (ACCORD BP) trial to all adults with diabetes in the United States.
