Doubly Robust Methods for Recurrent Event Outcomes: Causal Effects of Blood Pressure Medications on Acute Kidney Injuries

Evaluating the average causal effects of treatment strategies on recurrent event outcomes, such as heart attacks or renal failure, is important in clinical and medical research. However, the analysis becomes increasingly complex as multiple interacting factors are considered within a longitudinal setting. In this paper, we use advanced methodologies to estimate the average causal effects of standard versus intensive blood pressure-lowering therapies on acute kidney injury recurrences. We address time-varying treatment and confounding, and model misspecification during the identification and estimation processes for the effect estimands. We analyze the Systolic Blood Pressure Intervention Trial data set using our proposed method, accounting for medication adherence and the (semi-)competing risk of death observed in the data.