Making Bariatric Surgery Available to More Patients and Identifying Those Likely to Benefit the Most

Patients who are obese and have type 2 diabetes mellitus (T2DM) often desire bariatric surgery with hopes of weight loss and diabetes remission. Currently, the National Institutes of Health (NIH) Guidelines—guidelines that were established in 1991 and are endorsed by the Centers for Medicare and Medicaid—only recommend that patients with T2DM and body mass index (BMI) greater than 35 undergo bariatric surgery. Patients with a lesser degree of obesity usually have only one option: intensive medical weight management (MWM) with diet and medication. The Agency for Healthcare Research and Quality (AHRQ) has prioritized comparative effectiveness research regarding bariatric surgery in patients with BMI less than 35.

Researchers from the New York University School of Medicine collaborated with several New York City programs to study this issue. Their study comparing bariatric surgery to intensive MWM in T2DM patients who are ineligible for bariatric surgery under current NIH criteria appears in the October 2014 issue of Annals of Surgery.

These researchers also assessed whether soluble form of receptor for advanced glycation end products (sRAGE) levels might identify patients most likely to benefit from surgery. The receptor for advanced glycation end products (RAGE) binds multiple ligand families that are linked to hyperglycemia. Once activated, RAGE promotes pathogenesis of diabetic vascular complications, and in fact is a major influence. These researchers’ interest in sRAGE was based on mouse studies that found that mice that are devoid of RAGE and that are fed high-fat diets are protected from diet-induced obesity. Further, treating diabetic mice with sRAGE significantly reduced body weight gain. sRAGE is present in human plasma and may be a biomarker of vulnerability to obesity and diabetes.

This small study enrolled 57 T2DM patients with BMI levels between 30 and 35 and who otherwise met the criteria for bariatric surgery. The participants were randomized to MWM or the patient’s preferred bariatric surgery (bypass, sleeve, or band).

Patients who underwent surgery were more likely to experience improvements in insulin resistance than those on MWM. Sixty-five percent of surgical patients experienced diabetes remission at 6 months compared to none in the MWM group. Patients in the surgery arm had lower HbA1c (6.2 vs. 7.8), lower fasting glucose (99.5 vs. 157), and fewer T2DM medication requirements (20% vs. 88%) at 6 months.

Patients in the surgery arm lost an average of 7 points on their BMI compared to 1 point in the MWM arm.

This study shows that surgery was very effective in the short-term in patients with T2DM and BMI levels ranging from 30 to 35. It’s a preliminary work showing that sRAGE may be a biomarker to identify patients who are likely to have the best prognoses after bariatric surgery.