March 27, 2012
Bariatric Surgery Superior To Intensive Therapy For Obese Patients With Type 2 Diabetes
First-of-its-kind study also shows surgery results in fewer medications, greater weight loss after 1 year
Bariatric or "metabolic" surgery is more effective than intensive medical management alone when it comes to managing uncontrolled type 2 diabetes in overweight or obese patients after one year, according to research presented today at the American College of Cardiology's 61st Annual Scientific Session. The Scientific Session, the premier cardiovascular medical meeting, brings cardiovascular professionals together to further advances in the field.
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. Patients undergoing one of two stomach-reducing procedures — either laparoscopic gastric bypass or sleeve gastrectomy — in addition to medical therapy were three to four times more likely to achieve glycemic control (a measure of diabetes control defined using HbA1c) after one year of treatment compared to those who only received intensive medical therapy. STAMPEDE is the first randomized controlled trial to compare the effect of these two procedures to intensive medical therapy in helping patients achieve target goals.
Although the American Diabetes Association recommends an HbA1c of less than 7 percent, researchers set a more aggressive (≤ 6.0 percent) target as a primary endpoint for this trial. This was achieved in 12.2 percent of the medical treatment group versus 42.0 percent for gastric bypass (P=0.002) and 36.7 percent for sleeve gastrectomy (P =0.008). In addition, people in the surgical groups had much larger reduction in their HbA1c (2.9 vs. 1.4 points), significantly greater weight loss, and reduced reliance on medications compared to those receiving medical therapy only.
"For about a century, we have been treating diabetes with pills and injections and this is one of the first studies to show that surgical therapy may, at least in some patients, be much more effective than the polypharmacy approach to treating this disease," said Philip Schauer, MD, professor of surgery, director of the Bariatric and Metabolic Institute, Cleveland Clinic, and the study's lead investigator. "It's a potential paradigm change. In patients with moderate to severe diabetes, medication therapy alone can only get them so far; they are often still well above the target of good glycemic control."
The only other randomized control trial to look at gastric surgery (gastric banding, specifically) compared to medical therapy found a majority of patients undergoing surgery were able to put their diabetes in remission. STAMPEDE included patients with more severe diabetes than the previous study; at the start of the trial, the average patient had an HcA1c of 9.2±1 percent, was living with uncontrolled diabetes for eight or more years and was taking three or more antidiabetic medications and three or more cardiovascular medications.
A total of 150 patients (49±8 years, 66 percent female) were randomly assigned to one of three treatment groups: 1) intensive medical therapy only, which includes a combination of counseling, lifestyle changes and medications, 2) medical therapy plus Roux-en-Y gastric bypass or 3) medical therapy plus sleeve gastrectomy. Sleeve gastrectomy entails removing part of the stomach to reduce its volume by 75 to 80 percent; gastric bypass in the simplest terms 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 expended) and the second to connect the new gastric pouch directly into the intestine to bypass the stomach. All patients had some degree of obesity (body mass index, BMI, of 27 to 43 kg/m2). Secondary outcomes included safety and adverse event rates, measures of glycemic control, weight loss, co-morbidity status and cardiovascular risk profile.
At 12 months post-randomization, glycemic control improved in all three groups with a mean HbA1c of 7.5 percent ±1.8, 6.4 percent ±0.9, and 6.6 percent ±1.0 for medical therapy, gastric bypass and sleeve gastrectomy, respectively. In general, there were no major differences in blood pressure and cholesterol control between the groups. Patients in the surgical groups saw a significant improvement in glycemic control and were able to dramatically reduce the number of glucose, cholesterol and blood pressure-lowering medications they were taking. Medication use generally increased for those in the medical treatment group.
"Even though patients were given very intensive treatment, including new drugs, the surgical therapies were still superior," said Dr. Schauer. "The improvement in patients undergoing surgery was so rapid that many were able to come off of their medications before leaving the hospital."
Weight loss was five times greater for patients who received gastric bypass or sleeve gastrectomy compared with medical therapy (roughly 55 to 64 pounds compared to 12 pounds). Dr. Schauer said the findings suggest that even those patients who are not severely obese (those with a BMI of 27, for example), may benefit from surgery in much the same way as those with a higher BMI. 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.
But Dr. Schauer said surgery is not without risks. There was, as expected, a higher rate of complications in the surgery groups; however, there were no related deaths or life-threatening or debilitating complications. The most common issues were short-term dehydration, bleeding and one leak. Four out of 100 surgical patients needed operative intervention to manage complications occurring within the 12-month follow-up period.
Additional studies are needed to see whether these results are sustained and to look at clinical endpoints such as heart attack, stroke, renal failure and blindness. In addition, more research is needed to understand the mechanism by which gastric surgery is having such an immediate and significant effect on glycemic control.
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