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ATLANTA -- Bariatric surgery's beneficial effects for type 2 diabetes were significantly greater than even the most rigorous medical and lifestyle interventions, a researcher said here.

At 1 year, 60% of patients who had undergone gastric bypass were in diabetes remission, compared with only 6% of those treated with an intensive medical/lifestyle program (P=0.002), reported , of the University of Washington in Seattle.

In addition, weight loss at 1 year totaled 25.8% after compared with 6.4% with the nonsurgical approach (P<0.001), he reported during

"It's well known that gastric bypass is a tremendously powerful intervention against type 2 diabetes, leading to full remission in most cases. Nonetheless, you don't find it anywhere on the ," he said.

The reason for this, he suggested, is the paucity of level 1 evidence from randomized clinical trials comparing surgery with medical/lifestyle interventions.

"The problem is that it's incredibly difficult to do that kind of study because very few people are willing to toss a coin and randomly be allocated to things as divergent as a major operation that could kill you but if it doesn't it could save your life, or to keep plugging away with medicine. Most people have an opinion about this," he said at the meeting, which is jointly sponsored by and the

An additional factor is that traditionally, most studies have recruited patients from surgical or endocrine practices, which further creates bias.

To overcome this, Cummings and colleagues conducted a trial known as . They screened an electronic administrative database of an integrated health maintenance organization for eligible patients with type 2 diabetes whose body mass index (BMI) was between 30 and 40, cold-calling the patients to ask if they'd be interested in participating in the study.

They then thoroughly educated potential participants about the pros and cons of both surgical and nonsurgical approaches to obesity and diabetes, screening 2,000 and finding 43 who were willing to be randomized.

The lifestyle program consisted of an hour of aerobic exercise per day, 5 days a week in a dedicated research gym and close attention by a personal dietitian.

At baseline, the surgical and nonsurgical groups were generally well matched, except that the duration of diabetes in the surgical group was almost double that in the medical/lifestyle group (11.4 years versus 6.8).

That would handicap the surgical group, yet after a year there was a tenfold greater rate of remission with surgery, which was "surprising, given the rigor of the lifestyle intervention," he observed.

For glycemic control, both groups improved, and the decrease in hemoglobin A1c was only modestly greater for surgery, which fell from 7.7% to 6.4%, compared with 7.3% to 6.9% with the medical/lifestyle intervention.

However, patients in the medical group were taking far more drugs to achieve glycemic control, with about a 3.5 times greater burden of metabolic medications than the surgery patients.

Percent of body fat mass was reduced in both groups, but more so in the surgery group.

For lean body mass, the picture was somewhat different. "Despite the fact that they lost a considerable amount of weight, the medical/lifestyle group protected their lean body mass -- they were jumping up and down on StairMasters, after all," Cummings said.

In contrast, the surgical group lost almost one-third of their lean body mass.

"This is kind of a dirty secret that's not very well advertised for bariatric surgery, that you can lose a lot of lean mass and I don't think we fully understand the long-term consequences of that," he observed.

The surgical group experienced greater reductions in systolic blood pressure, but neither group showed a difference for diastolic blood pressure. Total cholesterol and LDL also didn't change.

But HDL increased significantly following surgery. "It's becoming clear that gastric bypass is quite good at raising HDL through mechanisms we don't very well understand," he said.

There was no difference at the end of the study in the number of patients on insulin, which suggests "that if you wait too long, to the point that patients are already insulin dependent, even surgery can't reverse it."

Most adverse events in the study were fairly inconsequential, but there were considerably more episodes of hypoglycemia in the medical group.

"Hopefully we can now take these data and begin to inform the question of where surgery should fit in our diabetes treatment algorithms," he concluded.

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