Bariatric Surgery More Efficient in Preventing Type 2 Diabetes in Obese Persons Than Usual Care

Preventing type 2 diabetes in obese persons is more efficient with bariatric surgery than usual care, according to a study released on Aug. 22 in The New England Journal of Medicine.

Overall results from the study, which looked at 1,658 non-diabetic patients who experienced bariatric surgery and 1,771 non-diabetic obese persons in a control group over a period of up to 15 years, showed bariatric surgery reduced long-term occurrence of type 2 diabetes in obese patients by 78 percent. Data showed an incidence rate of type 2 diabetes development in a control group to be 28.4 cases per 1000-person years (392 participants), while the incidence rate within the group that underwent bariatric surgery was only 6.8 cases per 1000 person-years (110 participants) [risk-adjusted HR with bariatric surgery, 0.17; 95 percent CI, 0.13—0.21]. The study also revealed that bariatric surgery effects were not influenced by body mass index (BMI), but instead by the presence or absence of impaired fasting glucose. Patients with impaired fasting glucose saw a decrease in risk of type 2 diabetes by 87 percent following bariatric surgery. According to the study authors, "this risk reduction is at least twice as large as that observed with lifestyle interventions in moderately obese, pre-diabetic persons." However, the authors noted that the lack of BMI influence on prevention implies that "anthropometric data are not useful in the selection of candidates for bariatric surgery."

Additional Resources
The study follows up on an earlier Swedish Obese Subjects (SOS) study from 2004 that looked at the benefits of bariatric surgery on type 2 diabetes prevention. It is unique in that it highlights the long-term prevention aspect that the procedure can have on type 2 diabetes. Participants in the study ranged from 37 to 60 years of age with a body mass index of 34 or more for men and 38 or more in women. Patients in the bariatric surgery group were treated with banding (19 percent), vertical banded gastroplasty (69 percent) or gastric bypass (12 percent). The authors acknowledged some limitations to the study, including non-randomization, methods of diabetes diagnosis, and low participation rate at the 15-year mark (36.2 percent had dropped out and 30.9 percent were not yet to the 15-year follow-up mark). However, they said results are valid due to "sensitivity analyses, including end-point imputations."

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