A1108
Title: A path specific effect approach to mediation analysis accounting for competing risks
Authors: Linda Valeri - Columbia University (United States) [presenting]
Abstract: In survival settings, competing events refer to any event that makes it impossible for the event of interest to occur. Not accounting for competing events by death can lead to biases caused by the fact that individuals who die do not have the opportunity to develop the event of interest. A path-specific effects framework is proposed to deal with competing events in the causal mediation setting in the presence of longitudinal mediators and time-to-event outcomes. The competing event is considered as a nested mediator with our mediator of interest, causal estimands, and identifiability conditions are proposed, and a mediational g formula is derived. Thus, two indirect effects are considered: the indirect effect through the history of the mediator of interest and the indirect effect through the history of the competing event. Additive hazard models are used to obtain effects estimates in an attributable risk scale. The algorithm is applied to real data from the multi-ethnic study of atherosclerosis. The potential mediating role of coronary artery calcification is evaluated on the association between heavy metals and cardiovascular disease, accounting for competing events by death.
