Controlling Diabetes with Bariatric Surgery

Obesity and type 2 diabetes mellitus continue to present one of the most difficult challenges to public health worldwide. Complications associated with diabetes include both macrovascular and microvascular diseases and events such as myocardial infarction, stroke, blindness, neuropathy, and renal failure. Healthcare providers aim to halt progression of diabetes by reducing hyperglycemia, hypertension, dyslipidemia, and other cardiovascular risk factors.

However, despite improvements in pharmacotherapy, <50% of patients with diabetes achieve and maintain therapeutic thresholds; glycemic control has been particularly difficult to maintain. Previous observational studies have suggested bariatric or metabolic surgery can quickly improve glycemic control and other cardiovascular risk factors in severely obese patients with type 2 diabetes, but there have been few randomized controlled trials comparing bariatric surgery with intensive medical therapy, particularly in moderately obese patients.

Researchers recently conducted the STAMPEDE (Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently) trial to compare intensive medical treatment with surgical treatment (Roux-en-Y gastric bypass or sleeve gastrectomy) in improving glycemic control in obese patients with type 2 diabetes. They reported trial results at the American College of Cardiology meeting in Chicago in March and online in the New England Journal of Medicine [10.1056/NEJMoal200225].

The trial’s primary end point was the proportion of patients with a glycated hemoglobin level of ≤6% 12 months after treatment. Secondary end points included levels of fasting plasma glucose, fasting insulin, lipids, and high-sensitivity C-reactive protein; the homeostasis model assessment of insulin resistance (HOMA-IR) index; weight loss; blood pressure; adverse events; coexisting illnesses; and changes in medications.

The study cohort included 150 obese patients with uncontrolled diabetes. Mean age was 49 years and 66% were women. The average glycated hemoglobin level was 9.2. Study participants were block-randomized in a 1:1:1 ratio to undergo intensive medical therapy alone or intensive medical therapy plus either gastric bypass or sleeve gastrectomy. Of the 150 patients in the original cohort, 140 (93%) completed all analyses. Medical therapy included lifestyle counseling, weight management, frequent home glucose monitoring, and the use of newer drug therapies (incretin analogues).

At baseline, there were no significant differences in the 3 study groups in patient characteristics. Mean body mass index (BMI) was 36; 34% (51/150) had a BMI of <35.

At 12 months of follow-up, 6.0% (5/41) of patients in the medical-therapy group reached the glycemic hemoglobin level target of <6%, compared with 42% (21/50) in the gastric bypass group (P=.002) and 37% (18/49) in the sleeve gastrectomy group (P=.008). There were no significant differences between the 2 surgery groups.

Mean levels of glycated hemoglobin and fasting plasma glucose were lower in the surgical groups compared with the medical-therapy group (P<.001 for both comparisons). The improvement was “large and rapid (by 3 months)” after each of the surgical procedures and was sustained over the year of observation with reduced hypoglycemic medication use.

The average number of diabetes agents per day tended to increase in the medical-therapy group and decreased significantly in the 2 surgery groups (P<.001 for both comparisons). Use of insulin remained high in the medical-therapy group and was reduced to 4% in the gastric bypass group and 8% in the sleeve gastrectomy group (P<.001 for both comparisons.

Weight loss was greater in the surgical groups, and the index for HOMA-IR improved significantly after bariatric surgery. There were no deaths, episodes of serious hypoglycemia requiring intervention, malnutrition, or excessive weight loss among the 3 groups.