Pretransplant sleeve gastrectomy improves kidney function

Pretransplant sleeve gastrectomy (SG) improves kidney function and may consequently increase rates of preemptive kidney transplantation in candidates not yet on dialysis, according to researchers at Mayo Clinic in Rochester, MN. However, they cautioned that these findings need to be confirmed by prospective studies with a well-matched cohort.

Aleksandra Kukla (Credit: Mayo Clinic)

"Our findings are that sleeve gastrectomy can buy some time for patients with kidney failure by improving their overall health," said Dr Aleksandra Kukla, a transplant nephrologist at Mayo Clinic 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 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.

In total, 21 kidney transplantation candidates with BMI above 35 kg/m2 underwent SG between February 22021 and October 2023, and were compared with 19 who did not have SG. The secondary endpoints included changes in BMI, requirements for antihyperglycemic and antihypertension medications and preemptive KT rates.

The mean estimated glomerular filtration rate (eGFR) increased from a pre-SG baseline of 16.7±5.4 to 23.5±8.3 and 23.5±8.6 mL/min per 1.73 m2 at 2 and 6 months after SG (p=0.002 and p=0.02, respectively), whereas it remained unchanged in the non-SG cohort: 13.8±3.4, 14.3±5.1, and 14.8±6.4 mL/min per 1.73 m2 at the pre-evaluation period, two months and six months. A higher baseline eGFR correlated with an improvement in eGFR after SG. The BMI and insulin requirements decreased only in the SG cohort. During the follow-up period of 5.1±4.6 months, five (23.8%) patients in the SG cohort and no patient in the non-SG cohort underwent preemptive kidney transplantation.

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," added 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."

Kukla explained 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.

"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," said Dr Ty S Diwan, 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 findings were reported in the paper, ‘Impact of sleeve gastrectomy on kidney function and preemptive transplant in kidney transplant candidates with obesity. Mayo Clinic Proceedings. To access this paper, please click here (log-in maybe required)