Weight loss surgery improves long-term survival and the prospect of kidney transplantation for obese patients with end-stage kidney disease (ESKD), new research suggests.

In a retrospective study of dialysis patients with a body mass index (BMI) of 35 or higher from the US Renal Data System registry (USRDS), the 1597 patients who underwent bariatric surgery had lower all-cause mortality at 5 years after adjustment for potential confounders compared with a matched control group of 4750 nonsurgical patients who received usual care (25.6% vs 39.8%), Kyle H. Sheetz, MD, MSc, of the University of Michigan in Ann Arbor, and colleagues reported in JAMA Surgery. Bariatric surgery was significantly associated with a 31% decreased risk of death compared with usual care. The decrease in death risk was driven by lower mortality from cardiovascular causes at 5 years in the surgery group compared with the control arm (cumulative incidence 8.4% vs. 17.2%). Compared with usual care, bariatric surgery was significantly associated with a 49% reduced risk of cardiovascular mortality, Dr Sheetz’s team reported.

In addition, a significantly higher proportion of bariatric surgery patients than controls underwent kidney transplantation at 5 years (cumulative incidence 33% vs 20.4%). Bariatric surgery vs usual care was significantly associated with a 1.8-fold increased likelihood of undergoing kidney transplantation, according to the investigators.

At 1 year, however, bariatric surgery was significantly associated with a higher cumulative incidence of death from any cause compared with usual care (8.6% vs 7.7%). Compared with usual care, bariatric surgery was significantly associated with a 1.4-fold increased risk of all-cause mortality at 1 year.


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“These findings suggest that bariatric surgery may warrant further consideration in the longitudinal management of patients with obesity and end-stage kidney disease,” according to the investigators.

“Bariatric surgeons need to look beyond the short-term increased risk of surgery in this patient population and consider the vast survival benefits for patients made eligible for kidney transplant,” Melina R. Kibbe, MD, and David A. Gerber, MD, of the University of North Carolina at Chapel Hill, commented in an accompanying editorial.

Several studies presented during the American Transplant Congress 2020 virtual scientific program also examined the effect of bariatric surgery and kidney transplantation. For example, among 908,570 new dialysis patients, obese patients (BMI of 40 kg/m2 or higher) had a significant 64% decreased likelihood of being wait-listed for transplantation within 1 year of dialysis than patients with a lower BMI, Linda Marie Lavenburg, DO, from the University of Pennsylvania in Philadelphia, and colleagues reported. In a second study, Rashikh A. Choudhury, MD, from the University of Colorado Hospital in Aurora, and colleagues modeled how the timing of bariatric surgery influences long-term survival for obese ESKD patients with a BMI of 45 kg/m2 seeking transplant candidacy. In the simulation, having sleeve gastrectomy before rather than after kidney transplantation was associated with improved access to kidney transplantation and longer mean survival by 1.9 years.

In a third study, Sarita Negi, PhD, from the Research Institute of the McGill University Health Centre in Montreal, Quebec, and collaborators compared outcomes for 3 patient groups who underwent kidney transplantion: 30 patients with a BMI greater than 30 kg/m2 who underwent bariatric surgery, 229 patients with a BMI greater than 30 kg/m2 who did not have weight loss surgery, and 614 nonobese patients (BMI less than 30 kg/m2). Bariatric surgery reduced the mean BMI from 41.6 to 31.9 kg/m2. A significantly greater proportion of weight-loss surgery and nonobese patients achieved an estimated glomerular filtration rate of more than 30 mL/min/1.73 m2 in the first 90 days (90% vs 90% vs 82%, respectively) and at 1 year (95.7% vs 94% vs 88%, respectively) after kidney transplantation compared with obese patients who did not have weight-loss surgery, Dr Negi’s team reported.

Prospective research is needed to corroborate these preliminary findings and define optimal ESKD candidates for weight loss surgery, timing, and methods.

References

Sheetz KH, Gerhardinger L, Dimick JB, Waits SA. Bariatric surgery and long-term survival in patients with obesity and end-stage kidney disease [published online May 27, 2020]. JAMA Surg. doi: 10.1001/jamasurg.2020.0829

Kibbe MR, Gerber DA. Bariatric surgeons should operate on patients with obesity who are receiving dialysis [published online May 27, 2020]. JAMA Surg. doi: 10.1001/jamasurg.2020.0862

Lavenburg L, Weinhandl E, Robinson L, et al. Morbid obesity: A growing barrier to early kidney transplant wait-listing in the United States. Presented at the ATC 2020 virtual scientific program. Am J Transplant. 2020;20 (suppl 3). Abstract B-223.

Choudhury RA, Yoeli D, Hoeltzel G, et al. Timing of bariatric surgery for obese kidney transplant candidates. Presented at the ATC 2020 virtual scientific program. Am J Transplant. 2020;20 (suppl 3). Abstract 130.

Negi S, Saberi N, Bouchard P, et al. The impact of weight reduction surgery and morbid obesity on renal function after transplantation. Presented at the ATC 2020 virtual scientific program. Am J Transplant. 2020;20 (suppl 3). Abstract 347.