Trends in Outcomes for Marginal Allografts in Liver Transplant.

Importance: Investigating outcomes after marginal allograft transplant is essential in determining appropriate and more aggressive use of these allografts.
Objective: To determine the time trends in the outcomes of marginal liver allografts as defined by 6 different sets of criteria.
Design, Setting, and Participants: In this case-control, multicenter study, 75 050 patients who received a liver transplant between March 1, 2002, and September 30, 2016, were retrospectively analyzed to last known follow-up (n = 55 395) or death (n = 19 655) using the United Network for Organ Sharing Database. The study period was divided into three 5-year eras: 2002-2006, 2007-2011, and 2012-2016. Kaplan-Meier survival analysis with log-rank test and Cox proportional hazards regression analysis were used to examine the allograft after transplant with marginal allografts, which were defined as 90th percentile Donor Risk Index allografts (calculated over the entire study period), donor after circulatory death allografts, national share allografts, old age (donors >70 years) allografts, fatty liver allografts, and 90th percentile Discard Risk Index allografts. Statistical analysis was performed from August to December 2019.
Main Outcomes and Measures: Allograft failure after transplant as defined by the Organ Procurement and Transplantation Network database.
Results: Among the 75 050 patients (44 394 men; mean [SD] age, 54.3 [9.9] years) in the study, Donor Risk Index, patient Model for End-stage Liver Disease scores, and balance of risk scores significantly increased over time. Multivariate Cox proportional hazards regression analysis indicated that 90th percentile Donor Risk Index allograft survival increased across the study period (2002-2006: hazard ratio, 1.41 [95% CI, 1.34-1.49]; 2007-2011: hazard ratio, 1.25 [95% CI, 1.17-1.34]; 2012-2016: hazard ratio, 1.10 [95% CI, 0.98-1.24]). Secondary definitions of marginal allografts (donor after circulatory death, national share, old age donors, fatty liver, and 90th percentile Discard Risk Index) showed similar improvements in allograft survival.
Conclusions and Relevance: The study's findings encourage the aggressive use of liver allografts and may indicate a need for a redefinition of allograft marginality in liver transplantation.