Estimating Differences in Restricted Mean Lifetime Using Additive Hazards Models under Dependent Censoring

In epidemiological and clinical studies, the restricted mean lifetime is often of direct interest quantity. The differences of this quantity can be used as a basis of comparing several treatment groups with respect to their survival times. When the factor of interest is not randomized and lifetimes are subject to both dependent and independent censoring, the imbalances in confounding factors need to be accounted. We use the mixture of additive hazards model and inverse probability of censoring weighting method to estimate the differences of restricted mean lifetime. The average causal effect is then obtained by averaging the differences fitted values based on the additive hazards models. The asymptotic properties of the proposed method are also derived and simulation studies are conducted to demonstrate their finite-sample performance. An application to the primary biliary cirrhosis (PBC) data is illustrated.