Weight-loss surgery linked to fewer diabetes complications

Large, long-term study finds half as much nerve, kidney, and eye disease after bariatric surgery than with usual care

SEATTLE, August 6, 2018—People with diabetes and severe obesity who had bariatric surgery were half as likely to develop certain complications of diabetes than were those who had no surgery, according to a new study published today in the Annals of Internal Medicine: “Microvascular Outcomes in Patients with Diabetes after Bariatric Surgery versus Usual-Care: A Matched Cohort Study.” The study was conducted by researchers at four health plans in the Health Care Systems Research Network: Kaiser Permanente in Washington, Northern California, and Southern California—and HealthPartners Institute in Minnesota.

More than 9 percent of adult Americans—about 30 million people—are estimated to have type 2 diabetes, according to the American Diabetes Association. The disease tends to worsen over time, with blood sugar levels rising along with the risks of developing large blood vessel (macrovascular) complications like heart attack and stroke, as well as small blood vessel (microvascular) complications affecting the nerves of the feet and hands (neuropathy), kidneys (nephropathy), and eyes (retinopathy).

Complications matter most

“We had already shown that around half of people with diabetes and severe obesity who receive bariatric surgery experience a seven-year remission of their diabetes when their blood sugar levels are normal without medication,” said senior author David Arterburn, MD, MPH, a senior investigator at Kaiser Permanente Washington Health Research Institute and an internist at the Washington Permanente Medical Group in Seattle.

“But to many people with diabetes, their blood sugar levels feel like an abstract concept,” said first author Rebecca O’Brien, MD, a bariatric internist at The Permanente Medical Group in Northern California. “What matters more to them is avoiding the harmful complications that can lead to limb pain and amputation, kidney failure, and blindness.”

This study included 3,949 Kaiser Permanente and 173 HealthPartners patients who received bariatric surgery. Their risk of all microvascular complications at five years after surgery was less than half that of a matched control group of more than 11,000 patients who received usual medical care that did not include surgery. All patients in the study had diabetes and severe obesity, defined as a BMI of at least 35 kg/m². Receiving bariatric surgery was associated with decreases of two thirds in nerve disease, one half in kidney disease, and one third in eye disease, respectively.

“These results suggest that everyone with diabetes and severe obesity should have a conversation with their doctor about whether bariatric surgery is a reasonable treatment option for their them, weighing the risks and benefits,” Dr. Arterburn said.

In next steps, the researcher team is conducting randomized clinical trials and observational studies of the impact of bariatric surgery versus usual medical care for people with diabetes.

Drs. O’Brien and Arterburn’s coauthors are Eric Johnson, MS; Mary Kay Theis, MA, MS; and Jane Anau, BS, at Kaiser Permanente Washington Health Research Institute, Seattle; David P. Fisher, MD; and Stephen Sidney, MD, MPH, at Kaiser Permanente in Northern California, Oakland; Karen J. Coleman, PhD, at Kaiser Permanente in Southern California, Pasadena; Emily B. Schroeder, MD, PhD, at the Institute for Health Research, Kaiser Permanente Colorado, Denver; Patrick J. O’Connor, MD, MA, MPH, at HealthPartners Institute, Minneapolis; Sebastien Haneuse, PhD, at the Harvard T.H. Chan School of Public Health, Boston; and Andy Bogart, MS, at the RAND Corporation, Santa Monica.

A National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK) award (#5R01DK092317-04) funded this study.

Diabetes is an active area of research at Kaiser Permanente, with more than 840 articles published since 2007.  An overview of diabetes research can be found at: https://share.kaiserpermanente.org/article/research-briefs

About Kaiser Permanente Washington Health Research Institute

Kaiser Permanente Washington Health Research Institute (KPWHRI) improves the health and health care of Kaiser Permanente members and the public. The institute has conducted nonproprietary public-interest research on preventing, diagnosing, and treating major health problems since 1983. Government and private research grants provide our main funding. Follow KPWHRI research on Twitter, Facebook, and LinkedIn, or subscribe to our free monthly newsletter. 

About Kaiser Permanente

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 12.4 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal Permanente Medical Group physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.