Effect of Recipient Body Mass Index on Kidney Transplantation Outcomes: A Systematic Review and Meta-analysis by the Transplant Committee from the French Association of Urology

Context The impact of recipient obesity on kidney transplantation (KT) outcomes remains unclear. Objective The aim of this study was to perform a systematic review and meta-analysis to appraise all available evidence on the outcomes of KT in obese patients (body mass index [BMI] ≥30 kg/m2) versus nonobese patients (BMI <30 kg/m2). Evidence acquisition A systematic review and meta-analysis was performed. Search was conducted in the MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and Cochrane databases to identify all studies reporting the outcomes of KT in obese versus nonobese recipients. Evidence synthesis Fifty-two articles met the inclusion criteria. Delayed graft function and surgical complications were significantly higher in obese recipients (delayed graft function: relative risk [RR]: 1.44, 95% confidence interval [CI]: 1.32–1.57, p < 0.01; surgical complications: RR: 1.74, 95% CI: 1.36–2.22, p < 0.0001). Five-year patient survival (RR: 0.96, 95% CI: 0.92–1.00, p = 0.01), 10-yr patient survival (RR: 0.90, 95% CI: 0.84–0.97, p = 0.006), and 10-yr graft survival (RR: 0.87, 95% CI: 0.79–0.96, p = 0.01) were significantly inferior in the obese group. Conclusions KT in obese recipients was associated with lower patient and graft survival, and higher delayed graft function, acute rejection, and medical and surgical complications than nonobese recipients. In the current situation of organ shortage and increasing prevalence of obesity, ways to optimize KT in this setting should be investigated. Patient summary Compared with nonobese population, kidney transplantation in obese recipients has inferior patient and graft survival, and higher medical and surgical complications.