Bariatric surgery is effective at reducing the BMI of obese individuals and in many cases ameliorating the severity of type 2 diabetes over the course of 1 to 2 years. Many longer-term studies have been observational in nature, and cannot provide data on the causes of the benefit. In order for reliance to be placed on such results, longer-term, randomized studies are necessary.
Dr. Philip R. Schauer of the Cleveland Clinic and colleagues recently reported on the progress of such a study in the New England Journal of Medicine. As part of the so-called STAMPEDE trial, they randomly assigned adults between the ages of 20 and 60 with poorly controlled type 2 diabetes, and a BMI between 27 and 43 to one of three groups. All participants had glycated hemoglobin levels (HbA1c), a measure of 2-3 month blood glucose control, which was greater than 7 percent. Doctors who treat diabetic patients encourage them to keep their HbA1c levels below 7 percent.
All the groups received intensive medical therapy. One group also had gastric bypass surgery, another had sleeve gastrectomy surgery, and the third group had only the medical therapy. These researchers had already reported on the results of the study one year post-surgery; the current report presented the results after three years and was based on the results of 137 patients..
The primary endpoint, or goal, of the study was a HbA1c below 6 percent, with or without use of diabetes medications. None of the groups reached this goal on average, although the bypass group and the gastrectomy group did reduce their levels to a significantly greater extent than the medicine only group. Again, the surgical groups lost significantly more weight than the medical group, and in addition the bypass group lost significantly more than the gastrectomy group. The amount of weight loss was a strong predictor of the extent to which the glycated hemoglobin was lowered.
As one might expect, the participants in the surgical groups used fewer medications to lower their blood glucose, and this was true to a greater extent in the gastric bypass group. They also had a higher quality of life, as indicated by examination of both mental and physical parameters.
ACSH s Dr. Ruth Kava opined, These results are certainly encouraging with respect to the persistence of the benefits of bariatric surgery. But it s still relatively early we hope these participants continue to accrue these benefits for many more years.