Hypothesis testing for an extended cox model with time-varying coefficients.

ABSTRACT: The log-rank test has been widely used to test treatment effects under the Cox model for censored time-to-event outcomes, though it may lose power substantially when the model's proportional hazards assumption does not hold. In this article, we consider an extended Cox model that uses B-splines or smoothing splines to model a time-varying treatment effect and propose score test statistics for the treatment effect. Our proposed new tests combine statistical evidence from both the magnitude and the shape of the time-varying hazard ratio function, and thus are omnibus and powerful against various types of alternatives. In addition, the new testing framework is applicable to any choice of spline basis functions, including B-splines, and smoothing splines. Simulation studies confirm that the pr

SUBMITTER: Saegusa T 

PROVIDER: S-EPMC4247822 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature