Observational studies have shown improvement in patients with type 2 diabetes mellitus after bariatric surgery.

In this randomized, nonblinded, single-center trial, we evaluated the efficacy of intensive medical therapy alone versus medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy in 150 obese patients with uncontrolled type 2 diabetes. The mean (±SD) age of the patients was 49±8 years, and 66% were women. The average glycated hemoglobin level was 9.2±1.5%. The primary end point was the proportion of patients with a glycated hemoglobin level of 6.0% or less 12 months after treatment.

Of the 150 patients, 93% completed 12 months of follow-up. The proportion of patients with the primary end point was 12% (5 of 41 patients) in the medical-therapy group versus 42% (21 of 50 patients) in the gastric-bypass group (P=0.002) and 37% (18 of 49 patients) in the sleeve-gastrectomy group (P=0.008). Glycemic control improved in all three groups, with a mean glycated hemoglobin level of 7.5±1.8% in the medical-therapy group, 6.4±0.9% in the gastric-bypass group (P<0.001), and 6.6±1.0% in the sleeve-gastrectomy group (P=0.003). Weight loss was greater in the gastric-bypass group and sleeve-gastrectomy group (−29.4±9.0 kg and −25.1±8.5 kg, respectively) than in the medical-therapy group (−5.4±8.0 kg) (P<0.001 for both comparisons). The use of drugs to lower glucose, lipid, and blood-pressure levels decreased significantly after both surgical procedures but increased in patients receiving medical therapy only. The index for homeostasis model assessment of insulin resistance (HOMA-IR) improved significantly after bariatric surgery. Four patients underwent reoperation. There were no deaths or life-threatening complications.

In obese patients with uncontrolled type 2 diabetes, 12 months of medical therapy plus bariatric surgery achieved glycemic control in significantly more patients than medical therapy alone. Further study will be necessary to assess the durability of these results. (Funded by Ethicon Endo-Surgery and others; ClinicalTrials.gov number, NCT00432809.)