Impact of Italian Score for Organ Allocation System on Deceased Donor Liver Transplantation: A Monocentric Competing Risk Time-to-Event Analysis

Background: Liver transplantation (LT) is the only definitive and curative treatment for patients with end-stage liver disease and hepatocellular carcinoma. We aimed to evaluate the impact of the Italian score for organ allocation (ISO) in terms of the waiting-list mortality, probability of LT, and patient survival after LT. Patient and methods: All of the adult patients on the waiting list for LT at our institute from January 2014 to December 2017 were included in the study. The probabilities of death while on the waiting list, dropout from the list, and LT were compared by means of cumulative incidence functions, in a competing risk time-to-event analysis setting. Uni- and multivariable logistic regression models were used to estimate and compare the probability of death and to find potential risk factors for waiting-list death. Results: There were 286 patients on the waiting list for LT during the study period, 122 of whom entered the waiting list prior to the implementation of ISO (Group A) and 164 afterward (Group B). Group A had 62 transplants, and Group B had 116 transplants. Group B showed a lesser probability of death (P = .005) and a greater probability of transplant (P < .001) compared to Group A. In the 2 groups, post-transplant survival was similar. Conclusion: Based on preliminary clinical experience from a single transplant center, the ISO allocation system demonstrated an overall reduced probability of patient death while on the waiting list without impairing post-LT survival, suggesting that the ISO system might represent an improved method of organ allocation, with a more beneficial distribution of livers.