Bariatric Surgery Bests Lifestyle in 2 More Diabetes Trials

Marlene Busko

June 05, 2014

Two small randomized, controlled trials illustrate that it would be feasible to conduct a larger, longer study to compare bariatric surgery with medical treatment for obese patients with poorly controlled type 2 diabetes.

The trials both found that gastric bypass produced greater weight loss and improvements in glycemic control compared with intensive lifestyle interventions at 1 year. However, these were small, preliminary studies, the authors caution, and it is as yet unknown if the benefits would be sustained.

"Our study really highlights some of the…problems that would have to be addressed before carrying out a larger trial," lead author of one of the studies, Anita P. Courcoulas, MD, from the University of Pittsburgh, Pennsylvania, told Medscape Medical News.

Funding would be needed for bariatric surgery in type 2 diabetic patients with a body mass index (BMI) of less than 35, which is not covered by insurance. And patient recruitment, randomization, and retention are problematic; for example, in their study only 10% of screened participants were randomized.

"From this study and some others it appears that at 1 to 2 years surgical procedures…are more effective to treat type 2 diabetes, but it's going to be very important to see what happens over the longer term, because we know in studies of obesity alone there is some weight regain," she said. This study is "an initial step."

A similar study by Florencia Halperin, MD, from Brigham and Women's Hospital, in Boston, Massachusetts, and colleagues reported comparable findings.

The two studies were part of seven that were funded by the National Institutes of Health to assess the feasibility of performing a large, long-term randomized trial of surgery vs medical management for obese patients with type 2 diabetes. They were published online June 3 in JAMA Surgery.

First Such Trial to Include a Gastric-Band Arm

Other research has shown that bariatric surgery is effective for weight loss and control of type 2 diabetes in patients with class 2 (BMI 35–39.9) or class 3 (BMI >40) obesity, but little is known about outcomes in patients with class I obesity (BMI 30–34.9), Dr. Courcoulas and colleagues write.

They compared the effectiveness of 3 treatments — Roux-en-Y gastric bypass (gastric bypass), laparoscopic adjustable gastric banding (gastric banding), and an intensive lifestyle weight-loss intervention modeled after the Action for Health in Diabetes (Look AHEAD) trial — in adults age 25 to 55 with BMI 30 to 40 and type 2 diabetes.

Of 667 potential participants who were screened, only 69 (10.3%) were randomized. Patients with a strong treatment preference, current smokers, or those unwilling to make required diet changes were excluded.

Among the randomized participants, 43% had a BMI of 30 to 34.9, and 81% were women. They had a mean age of 47.3 and an HbA1c of 7.9%.

After randomization, eight participants were excluded for refusing their allotted intervention or for current smoking. The remaining patients underwent gastric bypass (20 patients), gastric banding (21), or lifestyle intervention (20).

Gastric bypass resulted in a mean weight loss of 27% from baseline and a 50% partial and 17% complete remission of type 2 diabetes at one year.

This is the first US randomized controlled trial that included a laparoscopic gastric-band treatment option in this population for these end points, the researchers note. This surgery resulted in a mean weight loss of 17% from baseline and a 27% partial and 23% complete remission of type 2 diabetes at one year.

Participants treated with the intensive lifestyle intervention lost 10.2% of their baseline weight at 1 year but did not have any diabetes remission.

Three participants experienced a serious adverse event: 1 patient who had a gastric bypass developed an ulcer, and 2 patients who underwent gastric banding were hospitalized for dehydration.

Lack of Long-term Data Must Temper Enthusiasm

In a second study, Dr. Halperin and colleagues compared Roux-en-Y gastric bypass vs the Weight Achievement and Intensive Treatment (Why WAIT) lifestyle intervention.

Eligible participants were aged 21 to 65 with a BMI of 30 to 42, type 2 diabetes, a strong desire for substantial weight loss, and a commitment to lifelong medical and nutritional follow-up.

Of 822 potential participants, 43 were randomized, and 5 did not receive the intervention, leaving 19 who underwent gastric bypass and 19 who had the intensive lifestyle intervention.

The patients had a mean age of about 52, and more than half were women. At baseline, they had a mean BMI of about 36 and a mean HbA1c of approximately 8.5%.

At 3 months, all patients who had undergone gastric bypass had lost 10% of their weight, and 37% of patients in the lifestyle-intervention group had achieved this weight-loss goal.

At 1 year, 58% of patients who had gastric bypass vs 16% of patients in the lifestyle-intervention group achieved an HbA1c below 6.5% and fasting plasma glucose less than 126 mg/dL.

Weight, waist circumference, fat mass, lean mass, blood pressure, and triglyceride levels decreased more and HDL cholesterol increased more after gastric bypass compared with lifestyle intervention.

Serious adverse events in the 19 patients who had surgery included ischemic heart disease with resulting coronary artery bypass surgery, new breast-cancer diagnosis, nephrolithiasis, exacerbated depression with suicide attempt, and hip arthroplasty. Three participants in the nonsurgical arm had presyncope.

"At this time, the potential effect of long-term nutritional deficiencies and lack of data on cardiovascular and mortality outcomes must temper any enthusiasm for an endorsement of surgical procedures for diabetes management," Dr. Halperin and colleagues caution.

Risks vs Benefits Must Be Weighed

"Both papers…were a bit disappointing in the glycemic control obtained through what we would consider pretty effective and successful behavioral intervention," Christopher N. Ochner, PhD, from Icahn School of Medicine at Mount Sinai, New York, and a member of the Obesity Society Public Affairs Committee, told Medscape Medical News. Studies such as Look AHEAD have shown improvements in glycemic control with a 10% weight loss, he noted.

The two studies — though small and preliminary — showed that gastric bypass surgery is definitely more effective in terms of glycemic control, but it also has a much higher-risk profile. The slew of serious adverse events in the 19 patients in the study by Dr. Halperin et al was "particularly alarming," he notes.

But a clinician also has to consider the risk that uncontrolled diabetes poses for a particular patient. "The risk/reward profile needs to be considered for each…individual patient," Dr. Ochner summarized.

Now 13 Randomized Controlled Trials in This Indication

"Including these 2 studies, there have now been 13 small randomized controlled trials comparing surgery with medical treatment for both diabetes [and obesity] and just weight loss…and every single one of them shows surgery to be superior to medical treatment," Philip Schauer, MD, from the Cleveland Clinic, Ohio, commented to Medscape Medical News.

Among these is the STAMPEDE study, which Dr. Schauer and colleagues reported 3-year data from at the American College of Cardiology meeting in March — this also included patients with BMIs of lower than 35 (range, 27–43; average 36.7).

The patients in the lifestyle arms of these trials have "about as intense of a weight-loss diet and exercise program that you could possibly get," Dr. Schauer pointed out. But gut hormone changes after gastric bypass might explain why patients who had the surgery had better glycemic control, even though both groups lost weight, he suggested.

The largest barrier to not getting bariatric surgery is that some insurance companies do not cover the procedure, because of a lack of long-term evidence from large trials. For patients with high blood glucose levels despite being on optimal medical therapy, "surgery could take them from being poorly controlled to good control or even in some cases complete remission," he concluded.

The authors and editorialists have reported no relevant financial relationships.

JAMA Surg. Published online June 4, 2014. Abstract, Abstract

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