The impact of recipient obesity on outcomes after renal transplantation

The benefit of renal transplantation in obese patients is controversial, with many centers setting upper limits on body mass index (BMI) in consideration for listing patients for transplant. This study was undertaken to determine the effect of recipient obesity on delayed graft function (DGF) and graft survival after renal transplantation.

Retrospective review of all renal transplant recipients in the United Network for Organ Sharing database from January 1, 2004, through December 31, 2009, was performed. Primary endpoints were DGF and non-death-censored graft survival. Comparisons were made on the basis of the following weight classes: nonobese (BMI < 30), class I obese (30 ≤ BMI < 35), class II obese (35 ≤ BMI < 40), and class III obese (BMI ≥ 40).

Multivariable logistic regression indicated a significantly increased risk for DGF in obese patients. The odds ratios for DGF compared with nonobese patients were 1.34 [95% confidence interval (CI) 1.27-1.42; P < 0.001], 1.68 (95% CI 1.56-1.82; P < 0.001), and 2.68 (95% CI 2.34-3.07; P < 0.001) for the class I obese, class II obese, and class III obese groups, respectively. Class I obesity was not a significant risk for non-death-censored graft failure [hazard ratio (HR) 1.00, 95% CI 0.95-1.05; P = 0.901] compared with nonobese patients. Patients in the class II obese (HR 1.15, 95% CI 1.07-1.24; P < 0.001) and class III obese (HR 1.26, 95% CI 1.11-1.43; P < 0.001) groups were at a significantly increased risk for graft failure than their nonobese counterparts.

Obese patients in all weight classes are at an increased risk for DGF after renal transplantation, although differences in non-death-censored graft survival are such that transplantation should not be denied on the basis of BMI criteria alone.