Bariatric surgery can help, but not cure, diabetes

Gastric bypass surgery can improve glycemic control in adults with type 2 diabetes, but doesn’t cure diabetes, according to the largest community-based study of long-term diabetes outcomes after bariatric surgery, published online in Obesity Surgery.

The multisite 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 3 of these integrated healthcare 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.

“We found that for most of those people, diabetes either never remitted after gastric surgery or relapsed within five years,” says principal investigator David E. Arterburn, MD, MPH, a general internist and associate investigator at Group Health Research Institute.

The main impetus of the study is the growing numbers of Americans who are obese and have type 2 diabetes, according to Dr. Arterburn. Researchers have been disappointed with the results from attempts to treat diabetes with intensive lifestyle changes and intensive medical management, he says.

Prior research has shown that, in the short term, gastric bypass surgery can profoundly improve glycemic control in adults with type 2 diabetes-often even before they lose significant weight.

“That led some people to think that gastric bypass surgery might be a ‘cure’ for diabetes,” says Dr. Arterburn. “We wanted to see what happened in the longer term.”

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

“Managed care and hospital decision-makers need to find the best ways to care for their many patients who are obese and have diabetes-ways that will serve those patients best in the long run,” says Dr. Arterburn. “Of course prevention is the best medicine, and gastric bypass surgery isn't for everyone, but for patients who are already obese and have diabetes, our results suggest that it's never too early to start considering the surgery.”

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