Weight Loss Surgery May Defeat Diabetes

June 24, 2009 -- Weight loss surgery can improve or even resolve type 2 diabetes in the long term, according to two new studies.

Weight loss surgery is intended for people who are morbidly obese. The earlier it is done the greater the chances of the diabetes going into long-term remission, the researchers found.

They studied two types of surgery -- gastric bypass and gastric banding. "If you have diabetes [type 2] and you are heavy, early treatment with a gastric bypass gives you a very good chance of having your diabetes go into a durable remission," says James W. Maher, MD, professor of surgery at Virginia Commonwealth University, Richmond, and a co-author of the study looking at gastric bypass.

In the study, 90% of patients with type 2 diabetes had remission a year after the weight loss surgery, and about 57% were still diabetes-free five to 16 years later.

In a second study looking at gastric banding, "we had a significant majority of patients who had significant improvement and resolution, and it lasted the five years [of follow-up],'' says Christine Ren, MD, associate professor of surgery at New York University School of Medicine and senior author on the gastric banding study. At the five-year mark, 40% of patients had diabetes remission and another 43% had improvement in their diabetes.

Both studies are slated to be presented Wednesday at the annual meeting of the American Society for Metabolic & Bariatric Surgery in Dallas.

Gastric Bypass Study Details

Maher and colleagues followed 177 patients with type 2 diabetes who had the Roux-en-Y gastric bypass done between 1993 and 2003 and were followed from five to 16 years.

In the procedure, the stomach is reduced from about football size to golf ball size. The smaller stomach is attached to the second part of the small intestine. This bypasses the first part of the small intestine and decreases absorption of food.

Some patients took oral medications for their diabetes, while others were on insulin; another group only followed diet or lifestyle changes to control the disease.

Maher's team found that 157 patients had complete resolution of their diabetes after surgery, although it did not last in all the patients. The resolution was "durable" -- meaning still found at the end of follow-up -- in about 57%.

The 157 patients with initial resolution reduced their average body mass index (BMI) from 50.2 to 31.3. A BMI of 30 and above is termed obese. Those who maintained their weight loss were more likely to stay diabetes-free, Maher says. "Patients who had recurrence of the diabetes had some weight regain."

The outcome after surgery also was different depending on whether the patients were on dietary control, oral medicine, or insulin to manage their diabetes. "In people who had diabetes under dietary control, 97% had resolution at least at some point. Of those, only 24% had recurrences. With the patients on oral medications, 92% of them had resolution and it came back in about 34%. In the insulin dependent, 80% had resolution but it came back in 72% of that 80%."

"Those on insulin were 10 times as likely to have recurrences than those on dietary control [before the surgery],'' Maher tells WebMD. Women were five times as likely as men to have recurrence, he says, although he says that may be due to the smaller numbers of men in the study.

"The older patients were a little bit more likely to have recurrence of their diabetes," he says.

The overall message, he says, is that earlier treatment with weight loss surgery is more likely to produce remission.