Investigating Multiple Causal Mechanisms and Estimating NDE and NIE:A Joint Modeling Approach

Cheng Zheng Co-Author
University of Nebraska Medical Center
 
Fang Niu First Author
 
Fang Niu Presenting Author
 
Wednesday, Aug 7: 9:50 AM - 9:55 AM
3358 
Contributed Speed 
Oregon Convention Center 
In the context of HIV patients, over 20 distinct opportunistic infections (OIs) present complex effects on the health trajectory and associated mortality. It is crucial to differentiate among these OIs to devise tailored strategies to enhance patients' survival and quality of life. However, existing statistical frameworks for studying causal mechanisms have limitations, either focusing on single mediators or lacking the ability to handle unmeasured confounding, especially for the survival outcomes. In this work, we propose a novel joint modeling approach that considers multiple recurrent events as mediators and survival endpoints as outcomes, relaxing the assumption of "sequential ignorability" by utilizing the shared random effect to handle unmeasured confounders. We assume the multiple mediators are not causally related to each other given observed covariates and the shared frailty. Simulation studies demonstrate good finite sample performance of our methods in estimating both model parameters and multiple mediation effects. We apply our approach to an AIDS study and find that distinct pathways through the two treatments and CD4 counts impact overall survival via different OIs.

Keywords

Causal Inference

Joint Modeling

Mutiple Mediation Analysis

Recurrent Event

Survival Data 

Main Sponsor

Lifetime Data Science Section