Obesity and type 2 diabetes are likely to be the 2 greatest public health problems of the coming decades. The conditions are strongly linked, with the increased prevalence of diabetes correlating with the increased prevalence of obesity, the authors write. Weight control is perhaps the most important aspect of type 2 diabetes management. Recent evidence indicates that improvement in blood glucose control is related to the degree of weight loss.

Currently available lifestyle and pharmacological strategies provide only small to modest levels of weight loss, a problem compounded by patients with diabetes experiencing greater difficulty in losing weight than those without diabetes. Significant sustained weight loss as a result of bariatric surgery has never been formally studied as a treatment for type 2 diabetes in obese participants, according to background information in the article.

John B. Dixon, M.B.B.S., Ph.D., of Monash University, Melbourne, Australia, and colleagues conducted a 2-year trial involving 60 obese participants (body mass index [BMI] greater than 30, less than 40) to compare surgically induced weight loss with conventional therapy for the management of type 2 diabetes. Patients were randomized to receive either conventional diabetes therapy with a focus on weight loss by lifestyle change or laparoscopic adjustable gastric banding with conventional diabetes care. Of the 60 patients enrolled, 55 (92 percent) completed the 2-year follow-up.

The researchers found that remission of type 2 diabetes was achieved by 26 study participants (43 percent) at two years, with 22/30 (73 percent) from the surgical program and 4/30 (13 percent) from the conventional-therapy program. This represented 76 percent and 15 percent remission rates for those in the surgery and conventional-therapy groups, respectively. Greater percentage of weight loss at two years and lower baseline HbA1c values (hemoglobin used primarily to identify the average plasma glucose concentration) were independently associated with remission, but percentage of weight loss alone explained most of the variance.

After 2 years, the surgical group displayed a 5 times higher remission rate and 4 times greater reduction in HbA1C values than the conventional-therapy group, the authors write.

The surgical group achieved an average 20.7 percent body weight loss at two years, compared with 1.7 percent among the conventional-therapy group, representing a loss of 62.5 percent of excess weight (using BMI of 25 as ideal weight) in the surgical group compared with 4.3 percent in the conventional-therapy group. There were no serious complications in either group.

An important finding of this study is that degree of weight loss, not the method, appears to be the major driver of glycemic improvement and diabetes remission in obese participants. This has important implications, as it suggests that intensive weight-loss therapy may be a more effective first step in the management of diabetes than simple lifestyle change. This study shows that few participants achieved remission with a body weight loss of less than 10 percent, a level expected to produce important health benefits, the researchers add.

While caution is required in interpreting the longer-term benefits of surgery and weight loss, this study presents strong evidence to support the early consideration of surgically induced loss of weight in the treatment of obese patients with type 2 diabetes, they conclude.

jama.ama-assn/