Effect of donor genotype on patient survival after liver transplant: a retrospective cohort study.

Background: Several genetic variants are associated with chronic liver disease. The role of these variants in outcomes after liver transplantation (LT) is uncertain. The aim of this study was to determine if donor genotype at risk-associated variants in (rs738409 C>G, p.I148M) and (rs72613567 T>TA; rs80182459, p.A192Lfs∗8) influences post-LT survival.

Methods: In this retrospective cohort study, data on 2346 adults who underwent first-time LT between January 1, 1999 and June 30, 2020 and who had donor DNA samples available at five large Transplant Immunology Laboratories in Texas, USA, were obtained from the United Network for Organ Sharing (UNOS). Duplicates, patients with insufficient donor DNA for genotyping, those who were <18 years of age at the time of transplant, had had a previous transplant or had missing genotype data were excluded. The primary outcomes were patient and graft survival after LT. The association between donor genotype and post-LT survival was examined using Kaplan-Meier method and multivariable-adjusted Cox proportional hazards models.

Findings: Median age of LT recipients was 57 [interquartile range (IQR), 50-62] years; 837 (35.7%) were women; 1362 (58.1%) White, 713 (30.4%) Hispanic, 182 (7.8%) Black/African-American. Median follow-up time was 3.95 years. Post-LT survival was not affected by donor genotype but was significantly reduced among recipients of livers with two loss-of-function (LoF) variants compared to those receiving livers with no LoF alleles (unadjusted one-year survival: 82.6% vs 93.9%,  < 0.0001; five-year survival: 73.1% vs 82.9%,  = 0.0017; adjusted hazard ratio [HR], 2.25; 95% CI, 1.61-3.15 after adjustment for recipient age, sex, and self-reported ethnicity). Excess mortality was restricted to those receiving steroid induction immunosuppression (crude 90-day post-LT mortality, 9.3% [95% CI, 1.9%-16.1%] vs 1.9% [95% CI, 0.9%-2.9%] in recipients of livers with two vs no LoF alleles,  = 0.0012; age, sex, and ethnicity-adjusted HR, 2.85; 95% CI, 1.72-4.71,  < 0.0001). No reduction was seen among patients who did not receive steroid induction (90-day mortality 3.1% [95% CI, 0%-7.3%] vs 2% [95% CI, 0.9%-3.1%],  = 0.65; adjusted HR, 1.17; 95% CI, 0.66-2.08,  = 0.60).

Interpretation: Donor genotype adversely affects post-LT survival in patients receiving steroid induction. Additional studies are required to confirm this association.

Funding: The National Institutes of Health and American Society of Transplant Surgeons Collaborative Scientist Grant.