Bariatric surgery before and after kidney transplantation: long-term weight loss and allograft outcomes

Abstract Background Severe obesity is frequently a barrier to kidney transplantation, and kidney transplant recipients often have significant weight gain following transplantation. Objectives The goals of this study were to evaluate the long-term risks and benefits of bariatric surgery before and after kidney transplantation. Setting University Hospital, United States. Methods We performed a retrospective cohort study of 43 patients who had pretransplantation bariatric surgery and 21 patients who had posttransplantation bariatric surgery from 1994 to 2017 with propensity-score matching to identify matched controls using national registry data. Results Body mass index at the time of transplantation was similar in patients who underwent bariatric surgery before versus after transplantation (32 versus 34 kg/m2, P = .172). There was no significant difference in body mass index in the 5 years after bariatric surgery among patients who underwent bariatric surgery before versus after kidney transplantation (36 versus 32 kg/m2, P = 0.814). Compared with matched controls, bariatric surgery before (n = 38) and after (n = 18) kidney transplantation was associated with a decreased risk of allograft failure (hazard ratio .31 [95% confidence interval .29–0.33] and .85 [95% confidence interval .85–.86] for pre- and posttransplant, respectively) and mortality (hazard ratio .57 [95% confidence interval .53–.61] and .80 [95% confidence interval .79–.82] for pre- and posttransplant, respectively). Conclusions Bariatric surgery before and after kidney transplantation results in similar maintenance of weight loss and improved long-term allograft survival compared with matched controls. Bariatric surgery appears to be a safe and reasonable approach to weight loss both before and after transplantation.