50: Comparing modeling methods of determining survival benefit of liver transplantation

Thomas M. Menino Convention & Exhibition Center 

MELD 3.0 is a scoring system to prioritize patients for liver transplant (LT). We compared three methods of determining survival benefit (SB) of LT and effect modification of SB by MELD using time-dependent interaction terms: 1) Multivariable (MV) Cox model with time-dependent variables for LT and MELD - standard analysis, 2) MV sequential stratification (SS) model – SS matches time from listing to LT of LT recipients to waitlist candidates who have survived at least the same length of time, then uses stratified MV Cox model with robust standard errors, 3) Cox model using time-varying propensity score (tvPS)-matched data – uses hazard component from Cox model as tvPS, matches a treated patient to a not-yet-treated patient who has similar time-dependent covariates up to the moment when treatment occurs, and then uses stratified Cox model on matched data. Unlike the standard analysis, SS and tvPS ensure treatment groups are comparable at each time point when treatment eligibility changes. Overall survival benefit was the same across methods, but effect modification of SB by MELD varied. Further work is needed to investigate discrepancies and understand why there are differences.

time-varying propensity score matching

sequential stratification

survival benefit

Cox with time-dependent exposure 

Section on Statistics in Epidemiology