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

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.