Bariatric Surgery Curbs Diabetes in the Less Obese

August 26, 2013

By David Douglas

NEW YORK (Reuters Health) Aug 23 - Pooled data indicate that bariatric surgery can help treat diabetes in patients with a body mass index (BMI) of less than 35, according to New York-based researchers.

"The study shows that surgery is safe and effective for patients with BMI below 35," lead author Dr. Manish Parikh told Reuters Health by email. "Longer-term studies are needed to evaluate the long-term benefits."

In a report online July 25 in the Journal of the American College of Surgeons, Dr. Parikh of Bellevue Hospital Center and colleagues note that patients with a BMI beyond 35 meet the 1991 NIH Consensus Criteria for bariatric surgery. The approach is considered the most effective treatment for type 2 diabetes in such patients.

Although evidence is emerging on the efficacy of bariatric surgery in less obese patients they are primarily offered intensive diabetes management, including pharmacotherapy and nonsurgical weight loss.

To investigate further, the researchers conducted a meta-analysis of 22 prospective and 17 retrospective studies involving nearly 1,400 patients. Most studies were small, with a mean of 36 patients, and only three were randomized controlled trials.

The overall rate of diabetes remission at 12 months was 54.7%. Estimated rates varied by procedure, ranging from 32.7% for adjustable gastric banding to 80.5% for ileal transposition.

The rate of diabetes remission did not differ significantly among its various definitions. When the analysis was limited to the 17 reports that used strict diabetes remission criteria, involving 869 patients, the overall rate of diabetes remission at 12 months was 50.9%.

In the 22 reports that provided data on diabetes improvement, the estimated 12-month improvement rate was 94.5%.

The overall complications rate (5.4%) and mortality rate (0.4%) was consistent with those from other large studies involving bariatric surgery in patients with a BMI of 35 or more.

Nevertheless, the authors cautioned that the data are limited and short-term.

"There is an urgent need for large-scale randomized controlled trials comparing the effectiveness of bariatric surgery with intensive diabetes management" in these less obese patients, they note.

"Future studies," they add, "should use uniform criteria for the definition of diabetes remission."

"There is notable and diverse heterogeneity within the observational studies including range of enrolled type 2 diabetic patients, severity of type 2 diabetes (controlled or uncontrolled), and many patients lost to follow-up etc.," said Dr. Melinda Maggard Gibbons, who was not involved in the research. "The level and intensity of medical treatments following surgery varies widely."

"A critical appraisal of the quality of the observational studies is warranted," added Dr. Maggard Gibbons of Rand Health in Santa Monica, California. "Importantly, the authors acknowledge the reported rates of adverse events for these procedures, but it is not clear how they defined major complications. And these complications, especially in the observation studies are limited to surgeon self-reported events. As they point out in their discussion, caution must be applied when interpreting these overall results and applying them broadly."


J Am Coll Surg 2013.


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