The transplant index: A novel method to predict adult liver transplant waitlist outcomes

Background. The field of transplantation is shifting outcome priorities from 1-year survival to more comprehensive metrics including transplant rate and waitlist mortality. Identifying disenfranchised candidates (high waitlist death risk, low transplantation chance) can be a focus to improve outcomes. Methods. Given the waitlist outcomes (continued waiting, death, and transplantation), we aimed to identify factors predicting the likelihood candidates would undergo transplant or death by performing multivariate competing risk analyses of 121 198 candidates in the United Network for Organ Sharing database. We incorporated these probabilities (likelihood of transplantation and waitlist death) into the Transplant Index (TI) to identify disenfranchised candidates (high likelihood of death, low likelihood of transplantation). Results. Half of the patients had low incidences of death and transplantation within 90 days (TI-inactive). The remaining were stratified into 10 groups within a predictive index, the TI. Low TI groups (TI 10, 20, 30) had 90-day transplant rates of 50.8%, 41.6%, and 39.8% respectively, and their respective 90-day death rates were 22.8%, 15.1%, and 10.9%. High TI groups (TI 80, 90, >90) had 90-day transplantation rates of 53.7%, 64.3%, and 73.9%, respectively, and 90-day death rates of 5.9%, 6.5%, and 6.7% respectively. As TI increased, the likelihood of transplantation increased and that of death decreased. Low-TI groups represent the disenfranchised candidates. Conclusions. The TI identifies disenfranchised candidates on the adult liver transplant waitlist. This is the subgroup that would benefit the most from efforts to increase access to transplantation.