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STAMPEDE 3 Results: Bariatric Surgery vs. Intensive Medical Therapy

It appears to offer better and more durable control of diabetes than medical therapy….

The take-home message from the STAMPEDE 3-year study was bariatric surgery was more successful then pharmaceutical treatment. STAMPEDE, a study of obese (average BMI 36.7), middle-age diabetics, most of whom were women was particularly interesting because the primary endpoint was not weight loss but HbA1c, that from Sangeeta R. Kashyap, MD, at the Cleveland Clinic.

More than a third of patients who had Roux-en-Y gastric bypass (37.5%) achieved an HbA1c level of 6.0% after 3 years, as did 24.5% of the patients who underwent sleeve gastrectomy. That was significantly better than the 5% of medically managed patients who reached goal (P<0.001 for bypass and P=0.01 for the sleeve).

But most important, Kashyap said, "was that we were able to get patients off insulin." At 3 years, 55% of the medically managed patients were using insulin, versus 6% of bypass patients and 8% of the gastrectomy patients.

The STAMPEDE results were reported as a late-breaking clinical trial at the American College of Cardiology meeting and simultaneously published in the New England Journal of Medicine.

At a press conference following the late-breaker presentation, ACC spokesperson Amit Khera, MD, of the University of Texas Southwestern Medical Center in Dallas, remarked on the durability of the surgeries, noting the difficulty in maintaining tight HbA1c control for 3 years, a feat not achieved in studies of medical therapies.

The 150 patients in the study were evenly randomized to gastric bypass, sleeve gastrectomy, or intensive medical therapy, and 137 were available for evaluation at 3 years.

Intensive medical therapy included lifestyle modification with diet and exercise counseling, insulin sensitizers, sulfonylureas, GLP-1 agonists, and insulin injections. Follow-up, including counseling sessions, was every 3 months for 2 years and then every 6 months.

Importantly, all three groups had reductions in HbA1c during the first 6 months, and then all began a gradual creep back up but in both surgery groups that "creep" was minimal and quickly plateaued. That was not the case for the medically managed patients.

In addition to meeting the primary endpoint, patients in the two surgery groups also achieved greater weight loss — average BMI was 28 in the bypass group and 29 in the sleeve group, versus 35 for the medical controls. That worked out to a mean weight loss of 26 kg (57 lbs.) at 3 years in the gastric bypass group and 21.3 kg (47 lbs.) in the other surgery group, compared with just over 4 kg (9 lbs.) in the intensive medical management arm.

After 3 years, the surgery patients, regardless of surgical assignment, were also using fewer antihypertensive drugs and fewer lipid-lowering medications, but there were no significant favorable changes in lipid profiles or in blood pressure.

Considering the two surgery groups, the bypass group did achieve marginally better outcomes than the gastrectomy group, and that echoes what has been seen in other trials, but Kashyap, who is an endocrinologist, said she was not willing to recommend one procedure over the other. Another bariatric procedure — gastric banding — was not studied by the STAMPEDE investigators.

The results were impressive, which suggests the need to consider surgery as a viable and perhaps preferred option.

The authors noted a number of limitations including inadequate "sample size and duration to detect differences in the incidence of diabetes complications, such as myocardial infarction, stroke, or death." But they noted that the trial protocol "specifies further follow-up at 5 years for all patients, which should allow additional assessment of even longer-term efficacy and safety."

Dr. Kashyap noted that there was complete remission of diabetes in some surgery patients and that "the reduction in cardiovascular risk factors was sustained, allowing for reductions in lipid-lowering and antihypertensive therapies. Other benefits of surgery included a significant improvement in the quality of life. The question as to whether the documented benefits will reduce microvascular and macrovascular morbidity and mortality, as shown in nonrandomized studies, can be adequately answered only through larger, multicenter clinical-outcome trials."

Practice Pearls:
  • Surgery appeared to offer better and more durable control of diabetes than medical therapy, even when the patient did not meet morbidly obese criteria for bariatric surgery, researchers found.
  • Note that after 3 years, 55% of the medically managed patients were using insulin, versus 6% of bypass patients and 8% of the gastrectomy patients.

Schauer PR et al,"Bariatric surgery versus intensive medical therapy for diabetes — 3-year outcomes" NEJM 2014; DOI: 10.1056/NEJMoa1401329.