Aging of Liver Transplant Registrants and Recipients: Trends and Impact on Waitlist Outcomes, Post-Transplantation Outcomes, and Transplant-Related Survival Benefit

Abstract

Background & aims: Epidemiologic factors have generated increased demand for liver transplantation among older patients. We aimed to describe trends in age among liver transplant registrants and recipients and the effect of age on waitlist and post-transplantation outcomes and on transplant-related survival benefit.

Methods: We obtained data from the United Network for Organ Sharing on adults who were listed for liver transplantation (N = 122,606) or underwent liver transplantation (N = 60,820) from 2002 to 2014 in the United States. Competing risks analysis was used to model waitlist outcomes and Cox proportional hazards analysis to model post-transplantation survival. These models were also used to estimate 5-year transplant-related survival benefit for different age groups, calculated as the difference between waitlist and post-transplantation life expectancy.

Results: Between 2002 and 2014, the mean age of liver transplant registrants increased from 51.2 to 55.7 years, with a more prominent increase in hepatitis C virus-positive (50.9-57.9 years) than hepatitis C virus-negative (51.3-54.3 years) registrants. The proportion of registrants aged ≥60 years increased from 19% to 41%. In hepatitis C virus-negative patients, aging trends were driven by increasing proportions of patients with hepatocellular carcinoma or nonalcoholic steatohepatitis. Among transplant registrants, increasing age was associated with increasing mortality before transplantation and decreasing likelihood of transplantation. Among transplant recipients, increasing age was associated with increasing post-transplantation mortality. There was little difference in 5-year transplant-related survival benefit between different age groups who had the same Model for End-Stage Liver Disease score.

Conclusions: Dramatic aging of liver transplant registrants and recipients occurred from 2002 to 2014, driven by aging of the hepatitis C virus-positive cohort and increased prevalence of nonalcoholic steatohepatitis and hepatocellular carcinoma. Increasing age does not affect transplant-related survival benefit substantially because age diminishes both post-transplantation survival and waitlist survival approximately equally.

Keywords: Post-Transplantation Outcomes; Transplant-Related Survival Benefit; Waitlist Outcomes.