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Vagal nerve blockade effects on morbid obesity warrant further study

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Other Treatments Offer Better Results

The findings suggest that vagal nerve blockade has little to offer when compared with other treatments for morbid obesity, according to Dr. David E. Arterburn and Dr. David P. Fisher.

The treatment does not appear to be much more effective than an intensive lifestyle program, which in one study was shown to be associated with an 8.6% weight loss. Also, other procedures – including adjustable gastric banding, Roux-en-Y gastric bypass, and vertical sleeve gastrectomy – are associated with excess weight loss of between 50% and 68%, and thus are "clearly more effective for initial weight loss than vagal nerve blockade," Dr. Arterburn and Dr. Fisher wrote in an editorial (JAMA 2014;312:898-9).

The clinically important 8.6% rate of serious adverse events associated with intra-abdominal surgery and vagal nerve blockade in the study is also of concern, as are costs, which were not addressed by the authors, they noted.

"Although vagal nerve blockade therapy is an innovative approach, it does not appear to be a sustained, effective treatment for severe obesity," Dr. Arterburn and Dr. Fisher concluded.

Dr. Arterburn is with Group Health Research Institute, Seattle. He reported receiving institutional grants from the National Institutes of Health, the Patient-Centered Outcomes Research Institute, the Department of Veterans Affairs, and the Informed Medical Decisions Foundation, and receiving payment for travel expenses from the Informed Medical Decisions Foundation. Dr. Fisher is with the Permanente Medical Group, Kaiser Permanente Northern California, Bariatric Surgery Center, Richmond, Calif. He reported receiving institutional grants from the National Institutes of Health.


 

FROM JAMA

References

Intra-abdominal vagal nerve blockade to treat morbid obesity didn’t meet prespecified efficacy objectives in the randomized, double-blind ReCharge study, but treated patients did experience significantly greater weight loss than did those who underwent a sham procedure.

Mean excess weight loss was 24.4% (9.2% of initial body weight loss) in 162 patients who had a body mass index of 40-45 kg/m2 or 35-40 kg/m2 plus one or more obesity-related conditions, who underwent vagal nerve block therapy, compared with 15.9% (6% of initial body weight loss) in 77 patients in the sham group, for a mean between-group difference of 8.5 percentage points.

The difference was statistically significant, but it was less than the prespecified 10-point superiority margin, Dr. Sayeed Ikramuddin of the University of Minnesota, Minneapolis, and colleagues reported online Sept. 2 in JAMA.

At 12 months, 20% or more excess weight loss was achieved by 52% of patients in the vagal nerve block group, compared with 32% of patients in the sham procedure group. A total of 25% or more excess weight loss was achieved by 38% and 23% of patients in the groups, respectively, the investigators said (JAMA 2014;312:915-22).

Patients in the treatment group experienced more heartburn and dyspepsia, abdominal and other nonspecific pain, dysphagia, nausea, and eructation or belching than those in the control group. But these side effects were generally mild or moderate in severity. Serious adverse events associated with vagal nerve blockade occurred in 3.7% of treatment group patients, which was well below the 15% upper threshold for safety in the trial.

Additional study is needed to compare vagal nerve block with other obesity treatments, and to assess long-term durability and safety of the procedure, the investigators concluded.

This study was supported by EnteroMedics, which makes the vagal nerve blockade device used in the study. Dr. Ikramudden reported serving on the advisory board for Novo Nordisk and Medica, serving as a consultant for Metamodix and on an expert panel for OptumHealth, and receiving grant support from USGI Medical, ReShape Medical, and Covidien.

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