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/m2, n = 1020), overweight (BMI 25-29.9 kg/m2, n = 1002), moderately obese (BMI 30-34.9 kg/m2, n = 510) and severely-to-morbidly obese (BMI ≥35 kg/m2, n = 274). Logistic regression was used to estimate the association between BMI category and surgical site infections (SSIs). RESULTS: Recipients with BMI ≥35 kg/m2 had significantly higher rates of SSIs (P < .0001) compared with recipients in all other categories. On multivariable analysis, recipients with BMI ≥35 kg/m2 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.