Impact of Recipient Obesity on Kidney Transplantation Outcome: A Retrospective Cohort Study with a Matched Comparison

Abstract

The aim of this study was to evaluate the effect of a recipient's obesity on posttransplant complications and patient and graft survival. A single-institution, retrospective study was performed on obese renal transplant recipients (BMI ≥ 30 kg/m2, n=102) from January 2010 to December 2018, matched with non-obese recipients (BMI < 30 kg/m2, n=204). For comparison, for every obese patient we selected 2 nonobese patients with a similar age, sex, and period of transplantation. The comparative analysis included patient and graft survival as primary outcomes and graft function and postoperative complications as a secondary outcome. Recipient demographics were comparable in both groups except for diabetic nephropathy in obese patients (P=.0006). Obesity was strongly related to a poorer patient survival (risk ratio [RR]=2.83 confidence interval [CI] 95% 1.14-7.04; P=.020) but there was no observed difference in graft survival (P=.6). While early graft function was inferior in the obese population (RR=2.41; CI 95% 1.53-3.79; P=.00016), during late follow-up, no statistically significant differences were observed between both groups (P=.36). Obese recipients had a significantly higher risk of delayed graft function (RR=1.93; CI 95% (1.19-3.1), P=.0077), heart infarction (RR=7; CI 95% 1.68-29.26; P=.0042), wound infections (RR=8; CI 95% 1.96-32.87; P=.0015), diabetes aggravation (RR=3.13; CI 95% 1.29-7.6; P=.011), and surgical revision for eventration (RR=8; CI 95% 1.22-52.82; P=.026) when compared with nonobese recipients. Despite the inferior early kidney graft function in obese recipients, there was no difference observed at the long-term follow-up. However, recipient obesity demonstrated a negative effect on patient survival and postoperative complications.