Association of Bariatric Surgery With Long-Term Remission of Type 2 Diabetes and With Microvascular and Macrovascular Complications

Study Questions:

What are the long-term diabetes remission rates and the cumulative incidence of microvascular and macrovascular diabetes complications after bariatric surgery?


SOS (Swedish Obese Subjects) was a prospective matched cohort study conducted at 25 surgical departments and 480 primary health care centers in Sweden. Of patients recruited between September 1, 1987, and January 31, 2001, 260 of 2,037 control patients and 343 of 2,010 surgery patients had type 2 diabetes at baseline. Participation rates at the 2-, 10-, and 15-year examinations were 81%, 58%, and 41% in the control group and 90%, 76%, and 47% in the surgery group. Adjustable or nonadjustable banding (n = 61), vertical banded gastroplasty (n = 227), or gastric bypass (n = 55) procedures were performed in the surgery group, and usual obesity and diabetes care was provided to the control group. Primary outcomes were diabetes remission, relapse, and diabetes complications. Remission was defined as blood glucose <110 mg/dl and no diabetes medication.


Mean age was 49 years, and 40% were men. Mean body mass index (BMI) was 41 kg/m2 and slightly greater in the surgical group. The diabetes remission rate 2 years after surgery was 16.4% (95% confidence interval [CI], 11.7%-22.2%; 34/207) for control patients and 72.3% (95% CI, 66.9%-77.2%; 219/303) for bariatric surgery patients (odds ratio [OR], 13.3; 95% CI, 8.5-20.7; p < 0.001). At 15 years, the diabetes remission rates decreased to 6.5% (4/62) for control patients and to 30.4% (35/115) for bariatric surgery patients (OR, 6.3; 95% CI, 2.1-18.9; p < 0.001). With long-term follow-up, the cumulative incidence of microvascular complications was 41.8 per 1,000 person-years (95% CI, 35.3-49.5) for control patients and 20.6 per 1,000 person-years (95% CI, 17.0-24.9) in the surgery group (hazard ratio [HR], 0.44; 95% CI, 0.34-0.56; p < 0.001). Macrovascular complications were observed in 44.2 per 1,000 person-years (95% CI, 37.5-52.1) in control patients and 31.7 per 1,000 person-years (95% CI, 27.0-37.2) for the surgical group (HR, 0.68; 95% CI, 0.54-0.85; p = 0.001). The benefit of bariatric surgery on reducing vascular complications decreased with increasing duration of diabetes.


In this very long-term follow-up observational study of obese patients with type 2 diabetes, bariatric surgery was associated with more frequent diabetes remission and fewer complications than usual care. These findings require confirmation in randomized trials.


All the available data support the efficacy of bariatric surgery for morbid obesity with a particular value in diabetes. The results of this very long case-matched study support the recent third party payer acceptance of the interventions in nonmorbid obese patients, particularly when associated with diabetes.

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