Gastric bypass and sleeve gastrectomy - two of the most commonly used bariatric surgeries - are more effective than intensive medical therapy alone when it comes to managing uncontrolled type 2 diabetes in overweight or obese patients after three years, according to research presented at the American College of Cardiology’s 63rd Annual Scientific Session.
STAMPEDE is the largest randomized controlled trial with one of the longest follow-ups to compare the effect of these two procedures to intensive medical therapy in helping patients achieve glycemic control, defined in this study as a three-month average blood glucose level of 6 percent or lower - a more aggressive target than the American Diabetes Association recommendation of 7 percent. At the three-year follow up, only 5 percent of patients in the medical therapy group met this primary endpoint compared with 37.5 percent of gastric bypass and 24.5 percent of sleeve gastrectomy patients. Surgical patients also had a significant improvement in key cardiovascular risk factors including body mass index, weight control, triglycerides and high-density lipoprotein cholesterol compared to those receiving medical therapy alone.
“Both surgical options maintain their supremacy over standard intensive medical therapy at the three-year mark,” said Philip Schauer, M.D., professor of surgery, director of the Bariatric and Metabolic Institute, Cleveland Clinic, and lead investigator of the study. “There is this notion that if we keep adding medications and pushing patients to lose weight on their own, they will eventually achieve the same type of results as those undergoing surgery, but that wasn’t the case here.”
While the medical group showed an initial improvement in glycemic control within the first year, they were almost back to baseline by year three.
“Their [blood glucose level] went from 9.5 at the start of the study and dropped as low as 7.5 and then back up to 8.4 percent,” he said. In contrast, the surgical groups were able to maintain a lower glucose level with an average 2.5 percent reduction (9.3 at baseline and 6.7 and 7.0 for gastric bypass and sleeve gastrectomy at year three).
A total of 150 patients, age 41 to 57, were randomly assigned to one of three treatment groups: intensive medical therapy only, which includes a combination of counseling, lifestyle changes and medications, medical therapy plus Roux-en-Y gastric bypass, or medical therapy plus sleeve gastrectomy. Nearly all patients, 91.3 percent, completed 36 months of follow up. At the start of the trial, the average patient had an average blood glucose level of 9.2 percent, was living with uncontrolled diabetes for eight or more years and was taking three or more anti-diabetic medications and three or more cardiovascular medications. All patients had some degree of obesity. The sample was 66 percent female.
After three years, weight loss was five to six times greater for patients who underwent gastric bypass or sleeve gastrectomy on average compared with those in the intensive medical therapy group. On average the gastric bypass group lost 24 percent of their body weight, sleeve gastrectomy patients lost 21percent of their weight, and those on medical therapy alone lost 4 percent.
Quality of life measures were evaluated using a validated questionnaire and were significantly improved across multiple domains in both of the surgical groups. There was no improvement among those in the intensive medical therapy group.
Reliance on cardiovascular and glucose-lowering medications was drastically reduced in the surgery groups. At three years, 5 percent to 10 percent of these patients were using insulin compared to 55 percent of those in the medical therapy group.
New data considered kidney function as measured by the amount of albumin in the urine – a marker of kidney damage due to diabetes. Albumin was significantly lower in the gastric bypass group at year three, a trend that was not seen in either of the other groups.
Even those patients who are not severely obese, those with a body mass index of 27 to 35, appear to benefit from surgery in much the same way as those with a higher body mass index, a finding that Schauer hopes will encourage insurance companies to lower the threshold for covering such procedures.
Sleeve gastrectomy involves removing part of the stomach to reduce its volume by 75 to 80 percent; gastric bypass involves two operations, the first to reduce the stomach to 2 to 3 percent of its usual volume (going from the size of a football to a golf ball when expanded) and the second to connect the new gastric pouch directly into the intestine to bypass the stomach.
Roughly 80 percent of the 23 million American adults living with type 2 diabetes are overweight or obese, so these findings may apply to a significant percentage of patients with diabetes, according to researchers. People with uncontrolled diabetes have a much higher risk of cardiovascular complications, including heart attack, stroke and the development of secondary complications like neuropathy, retinopathy and amputation.
“Three years ago, top endocrinologists were curious about these surgeries, but due to the lack of randomized controlled trials and data, were reluctant to include it as a legitimate therapy,” Schauer said. “But now the evidence is mounting and we see the benefits of surgery over medical therapy for these patients.”
Bariatric surgery is not without risks and can cause complications such as bleeding, infection or blood clots. However, researchers report no major late surgical complications. The most common issues were reported at 12 months and included short-term dehydration, bleeding and one leak. Four out of 100 surgical patients needed operative intervention to manage complications occurring within the first year.
Schauer and his team will conduct long-term follow-up of these patients. Multicenter studies are needed to evaluate the effect of surgery and medical therapy on clinical outcomes such as heart attack, stroke, renal failure and blindness. Several studies have been published since STAMPEDE’s one-year results and show similar findings.
This study was funded by Ethicon Endo-Surgery, Inc., a subsidiary of Johnson & Johnson. Dr. Schauer is a consultant with Ethicon.
This study will be simultaneously published online in the New England Journal of Medicine at the time of presentation.
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The American College of Cardiology is a nonprofit medical society comprised of 47,000 physicians, surgeons, nurses, physician assistants, pharmacists and practice managers. The College is dedicated to transforming cardiovascular care, improving heart health and advancing quality improvement, patient-centered care, payment innovation and professionalism. The ACC also leads the formulation of important cardiovascular health policy, standards and guidelines. It bestows credentials upon cardiovascular specialists, provides professional education, supports and disseminates cardiovascular research, and operates national registries to measure and promote quality care.
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