Pre-Transplant Weight Loss and Survival after Kidney Transplantation

We examined post-transplant survival among obese kidney candidates who were temporarily designated waitlist inactive (status 7) due to their weight.

Using OPTN/United Network for Organ Sharing data, patient and graft survival of adult status 7 recipients with a registration body mass index (BMI) ≥30 kg/m(2) (n = 328) were compared to all others (controls; n = 74,066). Status 7 recipients were then matched to controls to assess whether pre-transplant weight loss was associated with a survival benefit.

Median BMI at registration (38 vs. 27 kg/m(2), p < 0.001) and transplant (36 vs. 27 kg/m(2), p < 0.001) and reduction in BMI while waitlisted (-5.0 vs. 0.0%, p < 0.001) were higher among status 7 than controls. Patient (status 7: 87.3%; control: 89.3%; p = 0.90) and graft survival (status 7: 82.9%; control: 81.6%; p = 0.75) were similar over 4 years. There was no association between status 7 and mortality (HR 0.96, 95% CI 0.59-1.57) or graft loss (HR 0.95, 95% CI 0.66-1.38) in the overall population nor between matched status 7 recipients and controls (patient survival: 86.0 vs. 87.5%, p = 0.20; graft survival: 82.6 vs. 77.2%, p = 0.61).

Among obese status 7 kidney candidates previously considered too obese for transplant, patient and graft survival were comparable to the general transplant population. No difference in survival was observed with pre-transplant weight loss.