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Original Investigation
September 3, 2014

Effect of Reversible Intermittent Intra-abdominal Vagal Nerve Blockade on Morbid Obesity: The ReCharge Randomized Clinical Trial

Author Affiliations
  • 1Department of Surgery, University of Minnesota, Minneapolis
  • 2University of Minnesota, Minneapolis; Scottsdale Healthcare Bariatric Center, Scottsdale, Arizona
  • 3Institute of Weight Control, Sydney, Australia
  • 4Adelaide Bariatric Centre, Adelaide, Australia
  • 5Department of Surgery, Tufts Medical Center, Boston, Massachusetts
  • 6Department of Surgery, Oregon Health & Science University, Portland
  • 7Scripps Clinic, San Diego, California
  • 8Division of General Surgery, Virginia Commonwealth University, Richmond
  • 9Department of Gastroenterologic and General Surgery, Mayo Clinic Rochester, Rochester, Minnesota
  • 10Division of General Surgery, Stanford University School of Medicine, Stanford, California
  • 11Department of Surgery, University of Michigan and Ann Arbor VA Hospital
  • 12North American Science Associates, Minneapolis, Minnesota
  • 13EnteroMedics Inc, St Paul, Minnesota
  • 14Division of General and Gastrointestinal Surgery, Brigham and Women’s Hospital, Boston, Massachusetts
  • 15Division of Endocrinology and Diabetes, Minneapolis VA Medical Center and University of Minnesota, Minneapolis
JAMA. 2014;312(9):915-922. doi:10.1001/jama.2014.10540

Importance  Although conventional bariatric surgery results in weight loss, it does so with potential short-term and long-term morbidity.

Objective  To evaluate the effectiveness and safety of intermittent, reversible vagal nerve blockade therapy for obesity treatment.

Design, Setting, and Participants  A randomized, double-blind, sham-controlled clinical trial involving 239 participants who had a body mass index of 40 to 45 or 35 to 40 and 1 or more obesity-related condition was conducted at 10 sites in the United States and Australia between May and December 2011. The 12-month blinded portion of the 5-year study was completed in January 2013.

Interventions  One hundred sixty-two patients received an active vagal nerve block device and 77 received a sham device. All participants received weight management education.

Main Outcomes and Measures  The coprimary efficacy objectives were to determine whether the vagal nerve block was superior in mean percentage excess weight loss to sham by a 10-point margin with at least 55% of patients in the vagal block group achieving a 20% loss and 45% achieving a 25% loss. The primary safety objective was to determine whether the rate of serious adverse events related to device, procedure, or therapy in the vagal block group was less than 15%.

Results  In the intent-to-treat analysis, the vagal nerve block group had a mean 24.4% excess weight loss (9.2% of their initial body weight loss) vs 15.9% excess weight loss (6.0% initial body weight loss) in the sham group. The mean difference in the percentage of the excess weight loss between groups was 8.5 percentage points (95% CI, 3.1-13.9), which did not meet the 10-point target (P = .71), although weight loss was statistically greater in the vagal nerve block group (P = .002 for treatment difference in a post hoc analysis). At 12 months, 52% of patients in the vagal nerve block group achieved 20% or more excess weight loss and 38% achieved 25% or more excess weight loss vs 32% in the sham group who achieved 20% or more loss and 23% who achieved 25% or more loss. The device, procedure, or therapy–related serious adverse event rate in the vagal nerve block group was 3.7% (95% CI, 1.4%-7.9%), significantly lower than the 15% goal. The adverse events more frequent in the vagal nerve block group were heartburn or dyspepsia and abdominal pain attributed to therapy; all were reported as mild or moderate in severity.

Conclusion and Relevance  Among patients with morbid obesity, the use of vagal nerve block therapy compared with a sham control device did not meet either of the prespecified coprimary efficacy objectives, although weight loss in the vagal block group was statistically greater than in the sham device group. The treatment was well tolerated, having met the primary safety objective.

Trial Registration  clinicaltrials.gov Identifier: NCT01327976