Gastric Bypass Sharply Lowers Death Risk for People With Diabetes, Study Finds

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The reduced mortality risk was not seen in patients who did not have diabetes before surgery. But in those who did, the results were dramatic.

Having gastric bypass sharply lowers the death risk for people with diabetes, cutting the overall mortality risk 56%, as well as individual rates from cardiovascular disease, respiratory ailments, and diabetes itself, according to a new study.

The findings, published Monday in Diabetes Care, the journal of the American Diabetes Association (ADA), add to “the growing body of literature on the numerous potential benefits of gastric bypass in patients with diabetes,” the study’s lead author, Michelle R. Lent, PhD, an investigator with the Geisinger Obesity Research Institute, said in an e-mail to The American Journal of Managed Care®.

The study followed 3242 patients who had Roux-en-Y gastric bypass (RYGB) between 2004 and 2015 and compared their health outcomes with a matched set of controls, based on age, gender, body mass index (BMI) and whether they had diabetes before surgery. Median follow-up was 5.8 years for those with diabetes and 6.7 years for those without diabetes.

While the overall death rates were not much improved for the surgery patients who did not start out with diabetes, compared with controls, (about 16%), the results for those who started with diabetes were dramatic.


The results confirmed what has been seen in many studies: gastric bypass can result in diabetes remission. After 2 years, 38.6% of the RYGB patients had experienced complete remission, compared with 0.4% of the control group who had diabetes. In addition, the authors wrote, “patients in our study who experienced partial or complete diabetes remission had a lower death rate compared with those without remission, which may relate to reduced cardiovascular risk.”

The ability of bartiatric surgery methods, including gastric bypass, to cause diabetes remission prompted the ADA to issue guidelines last year on when “metabolic surgery” should be provided to patients with diabetes, including teenagers.

This is the second important study in a week highlighting the benefits of bariatric surgery, especially for patients with diabetes. Last week, JAMA Surgery published results that suggested health plans that forced patients to wait until they were morbidly obese for surgery would miss the window when they could reap the greatest health benefits.

Lent said while this new study did not examine the issues in the JAMA Surgery article, a 2014 Geisinger study in the Journal of Obesity found that patients who start with a lower body mass index (BMI) are more likely to reach a final BMI of <30, which is below the defined level for obesity.

The authors state that while other researchers have found bariatric surgery lowers death rates for patients with diabetes, this study had a control group and followed patients for a longer period. “These data demonstrate a strong, long-term protective effect of bariatric surgery for patients with diabetes but no all-cause mortality risk reduction for patients without diabetes,” the authors write, although the patients without diabetes see other benefits, including improved quality of life.

People without diabetes who had surgery saw a reduced risk of death from cancer and respiratory ailments, but an increased risk of death from external causes, such as intentional self-harm.


Lent MR, Benotti PN, Mirshahi T, et al. All-cause and specific-cause mortality risk after Roux-en-Y gastric bypass in patients with and without diabetes [published online July 31, 2017]. Diabetes Care. 2017;40.