Quantifying the Effect of Transplanting Older Donor Livers Into Younger Recipients: The Need for Donor-recipient Age Matching.

BACKGROUND: Increasing recipient and donor age are independently associated with survival after liver transplantation (LT). Whether donor age differentially impacts post-LT outcomes based on recipient age is unknown.

METHODS: This was a retrospective cohort study using Organ Procurement and Transplantation Network data. All adult deceased-donor, single organ, primary LTs from 2002 to 2015 were included. Donor and recipient age were categorized as younger than 40 years, 40 to 59 years, and 60 years or older. Mixed-effects survival analysis evaluated the risk of graft failure and death according to the interaction of donor and recipient age categories.

RESULTS: Of 63 628 LTs, 6.6% were in recipients younger than 40 years, of which 51.4% used an age-matched donor younger than 40 years. There was a significant among-center variability unrelated to United Network for Organ Sharing region in the use of older organs in young recipients, ranging from 0% to 25% or greater (overall center median, 9.7%; interquartile range, 5.4-16.5%). There was a significant interaction between donor and recipient age (P < 0.05) such that the impact of older donor age was more pronounced in younger recipients. Transplanting livers from donors aged 40 to 59 years and 60 years or older was associated with worse graft survival in recipients younger than 40 years, but there was no difference based on donor age in recipients 60 years or older.

CONCLUSIONS: There is a differential impact of using older donors in younger recipients than that in older recipients. Given their longer expected post-LT survival and the ethical imperative to maximize utilization of the scarce resource of transplantable livers, efforts should be made to allocate the highest-quality organs to those most likely to derive lasting benefit.