A trial underway at New York-Presbyterian Hospital/Weill Cornell Medical Center is exploring whether surgery may be the best option to treat diabetes in these patients.

Until now, bariatric surgery was recommended only for individuals who are severely or morbidly obese, which means having a body mass index (BMI) of 35 or higher. After surgery, diabetic patients have improved blood sugar levels, a reduced need for medication, and a decreased risk for diabetes-related deaths.

But the new research is looking at individuals whose BMI is as low as 26. (Those whose weight is normal have a BMI between 19 and 25, according to Medical News Today, and overweight individuals have a BMI that ranges from 26 to 29.)

The current research at Weill Cornell, one of the first studies to test surgery as a treatment for Type 2 diabetes, is focusing on 50 type 2 diabetics who will either get surgery (the Roux-en-Y Gastric Bypass) or medical therapy. Both groups will receive counseling on diet, exercise, and lifestyle modification techniques.

Mitchell Roslin, MD, chief of obesity surgery at Lenox Hill Hospital in New York City, notes that bariatric surgery can improve diabetes-related symptoms in 90 percent of diabetics who are morbidly obese. He says that the improvement is not just due to weight loss that occurs following surgery. "The improvement in insulin sensitivity exceeds what would be predicted by weight loss alone," Roslin says. "So there is probably something about the way we are rearranging the GI tract that improves the diabetes."

"There are some interesting aspects to this study," says Vivek N. Prachand, MD, of the University of Chicago. "It's brought to the forefront how effective this surgery is, and how you can have either remission or significant improvement in diabetes after surgery."

It's known that patients who undergo bariatric surgery and lose a substantial amount of weight usually have a dramatic improvement in their diabetes, says Francesco Rubino, MD, chief of metabolic surgery at Weill Cornell Medical College, who is conducting the research with a team of co-investigators. "We have found that the effect of weight loss on diabetes is not only due to the weight loss but to a complex mechanism that changes the way the gastrointestinal tract signals," he says. "Experimental studies suggest that the surgery could even change the endocrine function of the GI tract."  

The current study, Rubino says, "will help us understand the causes behind diabetes and will help us know if the efficacy of surgery is so profound that it is even better than high-level medical treatment."

And, Rubino says, his research may help doctors figure out a better criteria than BMI to help them choose surgical candidates. "BMI does not accurately define the severity of diabetes," he says.

Right now, since insurance companies base whether or not they'll pay for surgery on a patient's BMI, the operation typically is not covered for patients who are just slightly obese. "New criteria could help patients as well as payers," says Rubino.

"It is still taking time for insurance companies to accept the indications of bariatric surgery for the severely obese," Prachand says. "If the surgery proves effective for patients who are just mildly obese, this would be a much bigger group for insurance companies to cover."

"Clinical trial will test whether surgery is the best option for Type 2 diabetes, even for patients who aren't obese." 11 February 2011. Medical NewsToday.com.