Weight Loss Surgery May Defeat Diabetes

Studies Show Gastric Banding and Gastric Bypass Offer Long-Term Help for Type 2 Diabetes

By Kathleen Doheny
WebMD Health News

Reviewed By Louise Chang, MD

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.

Gastric Banding Study Details

In the gastric banding study, Ren and colleagues looked at 95 patients with type 2 diabetes who had the banding surgery from January 2002 through January 2004. In the procedure, a silicone band filled with saline is wrapped around the upper part of the stomach. This creates a small pouch and causes patients to eat less because they feel full quickly.

At the end of follow-up, 40% were still diabetes-free, while another 43% had improvement in the disease. Their average BMI decreased to 35 from 46, and their average fasting blood glucose level decreased to nearly normal.

The finding, Ren tells WebMD, may correct the perception of some experts, whom she says believe the weight loss surgeries will not be that effective. "The morbidly obese diabetic has an excellent chance of having their diabetes go away completely and keeping their blood sugar normal up to five years."

Second Opinions

The new research builds on previous studies, says Scott Shikora, MD, president of the American Society for Metabolic & Bariatric Surgery and chief of general surgery, bariatric surgery, and minimally invasive surgery at Tufts Medical Center, Boston. "I think what it demonstrates is what we have seen in studies that date back several years, that bariatric surgery causes dramatic improvement or remission in type 2 diabetes. Currently, no other [diabetes] treatment out there can match the success of gastric banding or bypass."

The study results aren't surprising to Peter Galier, MD, an internal medicine specialist and former chief of staff at Santa Monica-UCLA Medical Center and Orthopaedic Hospital in California. But it is crucial, he says, to chose patients who are appropriate candidates for the bariatric surgery.

Recommendations issued by the American Diabetes Association in 2009 state that bariatric surgery should be considered for adults with BMIs of 35 or higher, especially if the diabetes is not ideally controlled with lifestyle or medication. Lifelong follow-up of the patients is necessary, according to the recommendations.

If a doctor screens the patient and knows that diet and exercise have been tried without success, "then this is a reasonable alternative," Galier says of bariatric surgery, "as long as people learn proper health and eating habits and keep off the weight."

SOURCES: James W. Maher, MD, professor of surgery, Virginia Commonwealth University, Richmond. Christine Ren, MD, associate professor of surgery, New York University School of Medicine. Scott Shikora, MD, president, American Society for Metabolic & Bariatric Surgery; professor of surgery, Tufts University School of Medicine; chief of general surgery, bariatric surgery, and minimally invasive surgery, Tufts Medical Center, Boston. Peter Galier, MD, internal medicine specialist; former chief of staff, Santa Monica-UCLA Medical Center and Orthopaedic Hospital; clinical professor of medicine, UCLA David Geffen School of Medicine, Los Angeles. 26th annual meeting, American Society for Metabolic & Bariatric Surgery, Dallas, June 21-26, 2009. American Diabetes Association: "Standards of Medical Care in Diabetes--2009."

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