Gastric bypass surgery helps diabetes but doesn’t cure it

People with earlier, less severe diabetes benefit more in HMO Research Network study

Seattle, WA—After gastric bypass surgery, diabetes goes away for some people—often even before they lose much weight. So does that mean gastric surgery “cures” diabetes? Not necessarily, according to the largest community-based study of long-term diabetes outcomes after bariatric surgery. For most people in the study, e-published in advance of print in Obesity Surgery, diabetes either never remitted after gastric surgery or relapsed within five years.

Among the two thirds of the study’s patients whose diabetes at first went away, more than a third re-developed diabetes again within five years after gastric surgery. After adding in the one quarter of patients whose diabetes never remitted after surgery, most (56 percent) of the study’s patients had no long-lasting remission of their diabetes following gastric surgery. However, when diabetes did go away, the research team extrapolated, it stayed away for a median of eight years.

Which kinds of obese people with type 2 diabetes are likely to get the most benefit from gastric surgery? “Our results suggest that, after gastric surgery, diabetes stays away for longer in those people whose diabetes was less severe and at an earlier stage at the time of surgery,” said principal investigator David E. Arterburn, MD, MPH, a general internist and associate investigator at Group Health Research Institute. “Gastric surgery isn’t for everyone,” he said. “But this evidence suggests that, once you have diabetes and are severely obese, you should strongly consider it, even though it doesn’t seem to be a cure for most patients.”

The multi-site study tracked 4,434 adults at Kaiser Permanente Northern California, Kaiser Permanente Southern California, and HealthPartners for 14 years: from 1995 to 2008. The research arms of all three of these integrated health care delivery systems—and Group Health Research Institute, where the study’s results were analyzed—belong to the HMO Research Network. The patients had type 2 diabetes that was either controlled with medication or else uncontrolled, and they were also obese enough to be candidates for gastric bypass surgery.

“Diabetes is an increasingly common disease that tends to keep getting worse relentlessly,” Dr. Arterburn said. More than 25 million American adults have diabetes—and as populations age and keep gaining weight, 50 million are predicted to have it by 2050. Already, diabetes accounts for 5 percent of all U.S. health care spending. And it raises the risk of blindness, kidney disease, heart attacks, strokes, and deaths.

“Prevention is by far the best medicine for diabetes,” Dr. Arterburn said. “Once you have diabetes, it’s really hard to get rid of. Attempts to treat it with intensive lifestyle changes and medical management have been disappointing.” For instance, the National Institutes of Health recently halted the Look AHEAD study of intensive lifestyle changes for people with diabetes. Despite improvements in risk factors like body weight, fitness, and blood pressure, sugar, and lipids, that study showed lifestyle changes did not lower the outcomes that matter most: heart attacks, strokes, and deaths.

“No wonder so many were excited to learn that diabetes can remit after gastric surgery—even, in some cases, before any significant weight loss—and many were hoping that gastric surgery might be a ‘cure’ for diabetes,” Dr. Arterburn said. “Our study is the first major evidence that diabetes often recurs after gastric bypass surgery.” Still, he added, even after diabetes comes back, having had a long period of post-surgery remission is likely to have many positive effects, such as fewer complications of diabetes: less damage to eyes and kidneys, and fewer heart attacks, strokes, and deaths. The researchers are now funded by the National Institutes of Health to study that possibility in this same population. Dr. Arterburn is also leading a randomized controlled pilot trial of intensive behavioral treatment vs. gastric surgery at Group Health with colleagues from the University of Washington.

It’s still not clear whether diabetes relapse happens because of gaining weight back or because of underlying the progression of diabetes. But patients’ weight—before and after surgery—was not strongly correlated with remission or relapse of diabetes in this population.

As part of the Developing Evidence to Inform Decisions about Effectiveness (DEcIDE) program, the Agency for Healthcare Research and Quality (AHRQ) of the U.S. Department of Health and Human Services funded this project under contract HHSA290-2005-0033-I-TO10-WA1, led by Dr. Arterburn.

Drs. Arterburn’s co-authors were: Andy Bogart, MS, and Mary Kay Theis, MA, MS, of Group Health Research Institute; David McCulloch, MD, of Group Health Cooperative; Nancy E. Sherwood, PhD, and Patrick J. O’Connor, MD, MPH, of HealthPartners Institute for Education and Research; Stephen Sidney, MD, MPH, of the Kaiser Permanente Northern California Division of Research, in Oakland; Karen J. Coleman, PhD, of Kaiser Permanente Southern California, in Pasadena; Guilherme M. Campos, MD, of the University of Wisconsin, in Madison; Sebastien Haneuse, PhD, of Harvard School of Public Health, in Boston; and Joe Selby, MD, MPH, of the Patient-Centered Outcomes Research Institute (PCORI), in Washington, DC. Dr. Arterburn is also an affiliate associate professor of medicine and Dr. McCulloch is a clinical professor of medicine at the University of Washington School of Medicine

Agency for Healthcare Research and Quality

The Agency for Healthcare Research and Quality (AHRQ) is the health services research arm of the U.S. Department of Health and Human Services (HHS), complementing the biomedical research mission of its sister agency, the National Institutes of Health. AHRQ is a home to research centers that specialize in major areas of health care research such as quality improvement and patient safety, outcomes and effectiveness of care, clinical practice and technology assessment, and health care organization and delivery systems. It is also a major source of funding and technical assistance for health services research and research training at leading U.S. universities and other institutions, as well as a science partner, working with the public and private sectors to build the knowledge base for what works—and does not work—in health and health care and to translate this knowledge into everyday practice and policymaking.

HMO Research Network

The HMO Research Network includes 19 research centers, each associated with a health care delivery system. Researchers at the centers collaborate on multi-site studies in real-world health care settings across the United States and in Israel. With access to information on more than 16 million ethnically and geographically diverse patients, these researchers are finding solutions for common and rare health problems. Since 1994, the Network has been answering pressing questions about keeping people healthy and delivering effective care.

About the Kaiser Permanente Division of Research

The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Located in Oakland, Calif., the Division of Research employs over 600 staff working on more than 250 epidemiological and health services research projects. For more information, visit www.dor.kaiser.org.

About the Kaiser Permanente Department of Research and Evaluation

The Department of Research and Evaluation (R&E) conducts high quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiology, health sciences, and behavioral research as well as clinical trials. Located in Pasadena, Calif., the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general population. Visit http://xnet.kp.org/research.

HealthPartners Institute for Education and Research

HealthPartners Institute for Education and Research is dedicated to improving health through discovery, the translation of research, and health professional education. Our researchers are dedicated to conducting high-quality, public-domain health research, proposed and led by multidisciplinary teams of independent PhD- and MD-level investigators rigorously trained in statistics, economics, epidemiology, and other fields. The Institute is part of a larger organization consisting of HealthPartners, Regions Hospital, and clinics.

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.