Several observational studies suggest that bariatric surgery leading to sustained weight loss confers substantial benefit on obese individuals with type 2 diabetes, but no randomized controlled trials have been reported. This unblinded randomized controlled trial enrolled 60 obese persons 20 to 60 years of age who had a body mass index above 30 but less than 40. Type 2 diabetes had been clearly documented within the past 2 years. Thirty patients were randomly assigned to undergo laparoscopic adjustable gastric banding, while 30 others received conventional treatment for diabetes focusing on weight loss through lifestyle changes. Remission of diabetes was defined as a fasting glucose level below 126 mg/dL and a glycated hemoglobin (HbA1c) value below 6.2% without glycemic medication.
After 2 years, type 2 diabetes had remitted in 43% of patients randomized to have surgery and in 13% of those treated conventionally. The respective remission rates among those completing the study were 76% and 15%. The relative risk of remission for the surgical group was 5.5, with a 95% confidence interval of 2.2–14.0. The surgical and control groups had lost a mean of 21% and 2% of body weight, respectively, after 2 years. Remission correlated independently with a greater percentage weight loss at 2 years and with a lower baseline HbA1c value. Only 12% of patients who lost less than 10% of body weight were in remission at 2 years. Weight loss correlated positively with the frequency of planned physical activity. In surgical patients, mean levels of both HbA1c and fasting plasma glucose were significantly lower than in conventionally treated patients. Surgical patients used significantly less pharmacotherapy for glycemic control. No serious complications were noted in either group of patients.
Although larger and longer-term studies are needed, these findings strongly support the view that surgically induced weight loss be considered at an early stage for obese patients who have type 2 diabetes.