Omnibus tests for comparison of competing risks with adjustment for covariate effects

This article develops omnibus tests for comparing cause-specific hazard rat es and cumulative incidence functions at specified covariate levels. Confid ence bands for the difference and the ratio of two conditional cumulative i ncidence functions are also constructed. The omnibus test is formulated in terms of a test process given by a weighted difference of estimates of cumu lative cause-specific hazard rates under Cox proportional hazards models. A simulation procedure is devised for sampling from the null distribution of the test process, leading to graphical and numerical techniques for detect ing significant differences in the risks. The approach is applied to a coho rt study of type-specific HIV infection rates.