July 22, 2025
Obesity and its associated comorbidities can result in decreased kidney function and the onset of renal failure. Patients with severe obesity frequently receive rejection for kidney transplantation. Previously, there hasn't been adequate research on weight-loss options for patients with renal failure. Researchers at Mayo Clinic in Rochester, Minnesota, examined the impact of sleeve gastrectomy surgery on renal function in patients with obesity.
"Our findings are that sleeve gastrectomy can buy some time for patients with kidney failure by improving their overall health," says Aleksandra Kukla, M.D., a transplant nephrologist at Mayo Clinic in Rochester and a co-author of the study. "For patients with renal disease, treating obesity should be a priority. Sleeve gastrectomy is a safe procedure that reduces comorbidities in patients with kidney failure."
In addition to providing an overall health benefit due to significant weight loss, the procedure led to improvements that could extend the time between the need for dialysis and transplant, even mitigating the need for dialysis or kidney transplantation in some circumstances. The article is featured in the June 2025 edition of Mayo Clinic Proceedings.
Improved kidney function after sleeve gastrectomy
The goal of the Mayo Clinic study was to investigate the impact of sleeve gastrectomy on kidney function, weight loss, comorbidities, preemptive kidney transplantation and dialysis initiation in patients with advanced chronic kidney disease who were seeking kidney transplantation at Mayo Clinic.
The study's authors compared the outcomes of patients who had bariatric surgery with candidates who met the criteria for sleeve gastrectomy but did not have the procedure. They also examined weight loss and changes in therapies for obesity-related comorbidities, including type 2 diabetes and hypertension, between the groups.
Overall, kidney transplant patients with obesity benefit from bariatric surgery, such as sleeve gastrectomy, which improves their kidney function. If patients are not already on dialysis, weight-loss surgery can translate to improved outcomes and allow patients to delay or avoid dialysis altogether, particularly if a living donor is available.
"Even if it is temporary, improving kidney function in patients with advanced kidney disease can have a positive effect on their overall health," says Dr. Kukla. "Delaying or avoiding dialysis in kidney transplant candidates could have a positive impact on post-transplant outcomes. Shorter dialysis and preemptive transplant lead to improved patient and graft survival."
Reduced comorbidities in patients with renal disease
Dialysis may cause cardiovascular risks, as well as increased rates of infection and hospitalization. Dr. Kukla says that even minor improvements can lead to a delay in dialysis and improved outcomes. Additionally, patients with improved kidney function may be candidates for novel diabetic therapies. For some patients, sleeve gastrectomy can lead to a reversal of diabetes altogether.
Bariatric surgery lowers a patient's body mass index (BMI) to an appropriate range for kidney transplantation and extends the window to preemptive kidney transplantation.
"For this study, we combined bariatric surgery and obesity treatment with transplant patients. We found that reaching these patients before dialysis improved their renal function," says Ty S. Diwan, M.D., a transplant surgeon at Mayo Clinic in Rochester and co-author of the study. "This is very important in clinical practice because it allows us to address weight as a pretransplant issue while the patient is still being worked up for transplant. In this way, the patient can be ready for transplant sooner. In addition, if renal function improves after bariatric surgery, it allows the patient a longer time with their native kidney function."
The kidney transplant program at Mayo Clinic evaluates patients with obesity for weight-loss surgery and implements the use of sophisticated testing to track improvement in kidney function and other markers post bariatric surgery. The program's multidisciplinary approach brings together kidney specialists, diabetes experts, surgeons, dietitians and physical therapists to help patients with kidney disease and obesity.
For more information
Navratil P, et al. Impact of sleeve gastrectomy on kidney function and preemptive transplant in kidney transplant candidates with obesity. Mayo Clinic Proceedings. 2025;100:942.
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