In more than half of obese patients with type 2 diabetes, their metabolic condition resolves after gastric bypass and they remain free from diabetes up to 16 years later, according to study findings presented last week at the 26th Annual Meeting of the American Society for Metabolic and Bariatric Surgery in Dallas.

In a study of 177 patients with diabetes who underwent gastric bypass for obesity, also referred to as bariatric surgery, between 1993 and 2003, the severity of diabetes before surgery was a key predictor of whether diabetes resolved in the long term. Moreover, long-term diabetes resolution correlated with the maintenance of weight loss.

"The most significant finding is that long-term resolution of diabetes seems to be linked to how severe the diabetes was at the time of surgery," senior author Dr. James W. Maher, from Virginia Commonwealth University, Richmond, told Reuters Health. "Patients with diet-controlled diabetes had a 75 percent likelihood of being diabetes-free at long-term followup, while the figure was 65 percent diabetes-free in patients who were originally controlled with oral medications and only 28 percent of insulin-dependent diabetics had long-term resolution."

After the gastric bypass procedure, 177 subjects were followed from 5 to 16 years and diabetes status was assessed with patient interview and a tally of diabetic medications.

Eighty-nine percent of patients had complete resolution of their diabetes, which correlated with a drop in average body mass index — the ratio of height to weigh — BMI from 50.2 to 31.3. Using BMI measurements, obesity is defined as a BMI of 30 or greater. Although diabetes did not resolve in the remaining patients, they nonetheless experienced significant weight loss.

Diabetes recurrence occurred in 43 percent of patients and was associated with regained weight. Men were more likely than women to resolve their diabetes initially (90.3 percent vs. 82.1 percent) and be free from the disease on long-term follow-up.

"Gastric bypass is the most effective therapy for diabetes," Maher emphasized. "It seems most likely to provide long-term relief when it is applied in obese patients early in the course of their disease. Primary care physicians need to consider this finding when they are faced with patients who are newly diagnosed with diabetes mellitus. These patients should strongly consider whether gastric bypass surgery is the best method for dealing with their disease."