Survival benefit in bariatric surgery kidney recipients may be mediated through effects on kidney graft function and improvement of co-morbidities: A case-control study

Background: Data on the benefits of bariatric surgery for morbid obesity among kidney transplant recipients are scarce.

Objective: To examine the effect of bariatric surgery on graft function and survival and on obesity-related co-morbidities.

Setting: University hospital.

Methods: This case-control study used retrospectively collected data of all kidney recipients who underwent bariatric surgery in our institution between November 2011 and August 2016 (n = 30, 11 females). Nonbariatric operated kidney recipients matched for age, sex, and time elapsed since transplantation served as controls (n = 50, 23 females). Main outcomes were renal function, graft loss events, mortality, and obesity-related co-morbidities.

Results: The mean follow-up duration was 2.4 ± 1.3 years for both groups. At final follow-up, there was an increase in estimated glomerular filtration rates for the bariatric surgery group, and a decrease for the controls (13.4 ± 19.9 and -3.9 ± 15.8 mL/min/1.73 m², respectively, P < .001). The chronic kidney disease classification improved in 9 bariatric surgery group patients and in 6 controls (P = .1). Two patients in the bariatric surgery group and 6 controls died. Total death or graft function loss during the follow-up was 6.7% and 16.7%, respectively (P = .3). The total numbers of co-morbidities and medications were lower in the bariatric surgery patients (-.7 and -2, respectively) and higher in the controls (+.3 and +1.1; P < .001) at study closure.

Conclusions: There was an improvement in renal function, graft survival, and obesity-related co-morbidities among kidney transplant recipients who underwent bariatric surgery compared with those who did not. These findings support bariatric surgery in this population and warrant prospective studies.