Summary measures in non-inferiority clinical trials with a time-to-event outcome: an empirical comparison of power

Our results empirically corroborate the theoretical advantage of difference in restricted mean survival time over the hazard ratio and difference in survival in non-inferiority clinical trials. This advantage is most apparent when estimation is done under proportional hazards. Choosing a relevant time point at which to evaluate the survival-based summary measures is an important aspect that should be carefully considered. We recommend incorporation of the difference in restricted mean survival time in the design and analysis of non-inferiority clinical trials when clinically justifiable. If appropriate, estimation under proportional hazards is preferable.