Bariatric surgery was more effective in achieving glycemic control in obese patients with type-2 diabetes than intensive medical therapy in a study presented March 26 at the American College of Cardiology annual conference in Chicago.

The findings come from the 150-patient randomized STAMPEDE trial, funded by Johnson & Johnson and the National Institutes of Health, comparing medical therapy with two forms of surgical treatment – gastric bypass or sleeve gastrectomy – in patients with a glycated hemoglobin level of greater than 7% and a body mass index of 27 to 43.

The advantage for surgery in controlling diabetes was “highly statistically significant,” said lead investigator Philip Schauer, professor of surgery and director of the Bariatric and Metabolic Institute at the Cleveland Clinic, at the ACC meeting.

At 12 months, the target glycated hemoglobin level of 6% or less was reached in five of 41 patients (12%) in the medical-therapy group, versus 21 of 50 (42%) in the gastric-bypass group and 18 of 49 (37%) in the sleeve-gastrectomy group.

Schauer noted that all patients in the gastric bypass group reached the target without the help of any diabetic medications, and 27% of those in the sleeve gastrectomy groups achieved the same outcome without drugs as well.

“That’s as close to a definition of remission that you can get to,” he said.

Data and discussion pointing to the potential for bariatric surgery to improve diabetes symptoms or even put the condition into remission has grown in recent years. But endocrinologists and the American Diabetes Association have urged caution in adopting the technique primarily to treat diabetes, particularly in patients not deemed morbidly obese (with a BMI of 35 or greater). (See Also see "CMS Proposes Coverage Of Surgery For Diabetes Only In Morbidly Obese" - Medtech Insight, 24 November, 2008..)

The results are not likely to shift the American Diabetes Association’s position that bariatric surgery should be reserved as an option for severely obese diabetics who have exhausted other interventions, an ADA official said.

In 2009, CMS issued a final coverage policy for bariatric surgery as a treatment for type-2 diabetes, but only in diabetics who are morbidly obese, meaning they have a body mass index of 35 or greater. (See [A#01350070021_b].)

Yet experts say that fewer than 50% of patients with moderate-to-severe type-2 diabetes actually achieve and maintain glycemic control through traditional intensive medical therapy, which includes lifestyle counseling, weight management, frequent home glucose monitoring and the use of newer drug therapies, including incretin analogues.

“This is a very important, almost epidemic, problem,” said Patrick O’Gara, ACC 2012 chair and director of clinical cardiology at Brigham and Women’s Hospital in Boston, during a pre-meeting conference with reporters March 13.

The STAMPEDE study “should really be the first opportunity that we’ll have to directly compare the efficacy and the safety of these two types of [surgical] procedures against medical therapy in patients with type-2 diabetes,” he said.

But the results are not likely to shift the American Diabetes Association’s current position that bariatric surgery should be reserved as an option for severely obese diabetics who have exhausted other interventions, said Vivian Fonseca, ADA president for medicine and science.

“The results make sense,” he told “The Gray Sheet.” However, the study’s major flaw, he said, is that among the patients enrolled and randomized to either surgery or medical therapy were patients who had already failed to respond to medical therapy.

“If you’ve already failed medical therapy, it’s going to take a miracle for you to suddenly respond to it,” he said.

Study Omits Banding

For the two surgical arms, investigators used a Roux-en-Y gastric bypass to create a smaller 15-to-20 mL gastric pouch or a sleeve gastrectomy involving a gastric-volume reduction of 75% to 80% by resecting the stomach.

Bariatric procedures were performed laparoscopically by a single surgeon with the use of instruments provided by Johnson & Johnson/Ethicon Endo-Surgery Inc., which partially funded the study, along with another J&J subsidiary, LifeScan Inc., which makes glucose meters, and NIH.

Adjustable gastric banding, such as with Allergan Inc.’s Lap-Band or J&J/Ethicon Endo-Surgery's Realize, was not analyzed in STAMPEDE. The American Society for Metabolic and Bariatric Surgery cited its omission as one weakness in the study’s design.

“Had they included a group of patients treated with adjustable gastric bands, they would have had a better idea of what maximal weight loss might have done separate from the metabolic effects of the sleeve and the bypass,” said ASMBS president Robin Blackstone.

The banding approach is on an upward volume trend in the U.S. relative to gastric bypass surgery, though earlier this year, a Swiss study showed that Roux-en-Y gastric bypass was associated with greater weight loss and results in better correction of some comorbidities compared to banding. (See Also see "Research In Brief" - Medtech Insight, 23 January, 2012..)

STAMPEDE investigator Schauer noted that other cardiovascular risk factors such as high-density lipoproteins, triglycerides and BMI were also greatly improved after surgery in the study.

For instance, in the surgical group there was about a 10-point drop in BMI at 12-month follow-up – equivalent to roughly 60 pounds – compared to less than a 2-point drop in the medical therapy group.

“The reduction in weight that can be achieved with bariatric surgery is associated with a whole host of improvements in metabolic indices, particularly those that surround the issue of insulin resistance, hyperglycemia and dyslipidemia,” ACC chair O’Gara explained.

Schauer admitted that one limitation of the study was its relatively short period of follow-up, noting that a four-year extension is ongoing to determine the durability of the effect.

The STAMPEDE data was published simultaneously with the ACC presentation in the New England Journal of Medicine.

In parallel, NEJM released data from a separate study comparing bariatric surgery – either bypass or biliopancreatic diversion – to “conventional” medical therapy.

Again, surgery resulted in better glycemic control than medicine, this time after two years of follow-up in 60 patients, reported a team from Italy and the U.S.

Bariatric Surgery Bests Medical Therapy In Treating Diabetes

More from Clinical Trials

More from R&D