Impact of Race on Outcomes in Obese Kidney Transplant Recipients: A Mate Kidney Analysis

Survival of patients on maintenance dialysis is longer in Black patients and patients who are obese. We sought to examine the interaction between transplant outcomes and self-reported race in obese kidney transplant recipients. Deceased donors for whom both kidneys were transplanted into first-time kidney alone recipients from 1/1/2000-12/31/2022 were identified from the United Network for Organ Sharing. Analysis was restricted to kidney recipients with BMI ≥ 30 kg/m2 who self-identified as White or Black. Mate-kidney regression models were used to evaluate delayed graft function (DGF), post-transplant mortality, uncensored graft failure, and death-censored graft failure. There were 15,458 recipients in 7,729 mate-kidney pairs, of which 30% were Black, 31% were White, and 39% were discordant for race. At study end, 5,292 patients had died, of whom 3,263 died with a functioning allograft. Death occurred in 30% of Black patients and 38% of White patients (P < 0.001). Allograft failures occurred in 39%. Adjusted mortality was lower in Black recipients, compared to Whites (HR = 0.84, 95%CI = 0.79, 0.90, P < 0.001). Death-censored graft failure was higher in Black recipients (HR = 1.20, 95%CI = 1.10, 1.30, P < 0.001), as was DGF (OR = 1.35, 95%CI = 1.19, 1.60, P < 0.001). In conclusion, we observed longer survival in obese Black kidney transplant recipients, compared to White recipients, despite increased risks for DGF and death-censored graft failure.