Association between bariatric surgery after kidney transplantation and graft and survival outcomes.

Bariatric surgery has been shown to be safe in chronic kidney disease and improves access of patients to transplantation. Whether bariatric surgery after kidney transplantation associates with improved graft or patient survival has not been examined nationally. We included adults with obesity who received a first kidney transplant according to the US Renal Data System between 2003-2019. We matched 4 controls to each case of bariatric surgery based on age at transplantation, sex, donor type, diabetes, and body mass index at transplantation (BMI). We examined the association between bariatric surgery and graft failure or death using multivariable Cox proportional hazards models and Fine-Gray models accounting for death as a competing risk. We included 770 patients, of whom 155 (20%) received bariatric surgery. Median age was 45 years and 56% were women. Receipt of bariatric surgery was associated improved graft survival (HR 0.57; 95% CI 0.34-0.98) in fully adjusted models, though findings did not consistently maintain statistical significance in competing risk analyses (SHR 0.60; 95% CI 0.35-1.02). Receipt of bariatric surgery was associated with lower risk of death (HR 0.45; 95% CI 0.26-0.76). In conclusion, bariatric surgery is associated with improved patient survival, and potentially graft survival after kidney transplantation.