The effect of obesity on renal transplant outcomes

Although obesity has been associated with improved survival on dialysis, its effects on renal transplant outcomes remain unclear. Previous studies have reported conflicting findings and have been limited by the use of outdated patient data, univariate analyses, and liberal transplant selection criteria. The present study aimed to evaluate the effect of obesity on renal transplant outcomes in a rigorously screened population.

A retrospective analysis was undertaken of all patients transplanted at the Princess Alexandra Hospital from 1 April 1994 to 31 March 2000. Patients were rigorously screened for cardiovascular disease before acceptance for transplantation. The effects of obesity on renal transplant outcomes were assessed by logistic and multivariate Cox regressions.

Of the 493 patients transplanted, 59 (12%) were obese (body mass index [BMI] 30 kg/m ). Obese patients were more likely to experience superficial wound breakdown (14% vs. 4%, P<0.01) and complete wound dehiscence (3% vs. 0%, P<0.01). Wound infections also tended to be more frequent in obese recipients (15% vs. 8%, P=0.11). There were no significant differences between the two groups with respect to operative duration, postoperative complications, hospitalization, delayed graft function, or acute rejection episodes. Five-year actuarial survival rates were comparable between the two groups with respect to graft survival (83% vs. 84%, P=NS) and patient survival (91% vs. 91%, P=NS). On multivariate analysis, BMI was an independent risk factor for wound breakdown (odds ratio 1.21, 95% CI 1.09-1.34, P<0.001), but not for other posttransplant complications, hospitalization, graft loss, or patient survival.

The only significant adverse effect of obesity on renal transplant outcomes was an increase in wound complications, which were generally of minor consequence. Provided that adequate care is taken to avoid transplanting patients with significant cardiovascular disease, obese recipients can achieve excellent long-term patient and graft survivals that are on par with their nonobese counterparts. Denying patients access to renal transplantation on the basis of obesity per se does not appear to be justified.