Retrospective analysis of the impact of severe obesity on kidney transplant outcomes

Background The prevalence of obesity among kidney transplant recipients is rising. We sought to determine the association between recipient body mass index (BMI) and post-transplant complications. Methods Single-center, retrospective cohort study of all adult kidney transplant recipients from 2004 to 2020. Recipients were stratified into four BMI categories: normal-weight (BMI 18.5-24.9 kg/m(2), n = 1020), overweight (BMI 25-29.9 kg/m(2), n = 1002), moderately obese (BMI 30-34.9 kg/m(2), n = 510) and severely-to-morbidly obese (BMI >= 35 kg/m(2), n = 274). Logistic regression was used to estimate the association between BMI category and surgical site infections (SSIs). Results Recipients with BMI >= 35 kg/m(2) had significantly higher rates of SSIs (P < .0001) compared with recipients in all other categories. On multivariable analysis, recipients with BMI >= 35 kg/m(2) had increased odds of SSIs compared with normal-weight recipients [odds ratio (OR) 3.34, 95% confidence interval (CI) 1.55-7.22, P = .022). On multivariable and Kaplan-Meier analyses, no BMI groups demonstrated increased odds for death-censored graft failure. Conclusion Severe obesity in kidney transplant recipients is associated with increased SSIs, but not kidney allograft failure.