Comparison of outcomes after living and deceased donor kidney transplantation: UK national cohort study.

BACKGROUND: Most kidneys for transplantation come from deceased donors, though healthy live individuals may also donate. Living donor transplants generally show better outcomes than deceased donor transplants, but it is unclear whether this reflects inherent benefits of having a living donor kidney or differences in donor and recipient characteristics. Using data from 10 915 UK kidney-only transplants, the aim of this study was to determine the causal effect of living donors on graft survival, considering all-cause death without graft failure as a competing risk. METHODS: This study used inverse probability of treatment weighting based on propensity scores to adjust for imbalances in baseline variables between recipients of living and deceased donor kidneys implanted between 2010 and 2021. The mean treatment effect, had all patients received kidneys from living donors, was estimated from differences in survival probabilities and restricted mean survival time using weighted competing risks models. RESULTS: After adjustment for key confounders, living donor kidney transplantation (LDKT) was associated with a 6.03% (95% c.i. 4.71% to 7.35%) lower 5-year risk of graft failure compared with deceased donor kidney transplantation (DDKT). Over 7 years, living donor recipients experienced an additional 0.36 (95% c.i. 0.29 to 0.43) years of graft survival. Benefits persisted across clinically relevant LDKT subgroups. CONCLUSION: LDKT is associated with superior graft survival compared with DDKT after adjusting for confounders. Findings highlight the importance of promoting living donor programmes whilst simultaneously identifying opportunities to enhance DDKT. Future work may clarify whether factors such as reduced cold ischaemia time drive these benefits.