Sequential log rank tests adjusting for covariates with the accelerated life model

Abstract

SUMMARY This paper presents a simple sequential method for comparing two treatments in randomized clinical trials which allows for the adjustment of other covariates with the accelerated life model. The new procedure is the same as the ordinary sequential log rank test except that the test statistic is calculated on an ‘adjusted’ time scale. This covariate adjustment can lead to more efficient designs of group sequential trials especially when the effects of covariates being adjusted for are strong. An aids example is provided.