Vagal Nerve Blockade for Obesity Treatment

Vagal nerve blockade might not be an effective therapy for obesity treatment…. 

A randomized controlled trial called EMPOWER showed that vagal nerve blockade could result in weight loss; however, the difference in weight loss between treatment and control groups was not significant. Also, the clinically important weight loss was related to hours of device use for both groups, suggesting that there was a possibility that weight loss in control patients resulted from receiving partial vagal blockade through low-energy safety or diagnostic checks.

Considering the results of the EMPOWER study, Dr. Sayeed Ikramuddin from the University of Minnesota, Minneapolis, and colleagues conducted a multicenter, randomized, double-blind study called ReCharge Study to further evaluate the effectiveness and safety of intermittent, reversible vagal nerve blockade therapy for obesity treatment.

In this study, 239 patients from 10 different sites in the United States and Australia were randomized to receive an active vagal nerve blockade device or a sham device. The coprimary efficacy objectives of the study 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.

At 12 months, the vagal nerve block group had a mean 24.4% excess weight loss vs. 15.9% excess weight loss in the sham group. Weight loss was statistically greater in the vagal nerve block group compared to the sham group (p=0.002); however, the mean difference in the percentage of the excess weight loss between groups was 8.5 percentage points, which did not meet the 10-point target (P=0.71).

As far as safety, the authors found that 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. Some of the common adverse events in the vagal nerve block group included mild to moderate heartburn and abdominal pain.

The authors concluded that vagal nerve block therapy was well tolerated and safe to use. Nonetheless, "the use of vagal nerve blockade therapy compared with sham control device did not meet either of the pre-specified efficacy objectives, although weight loss in the vagal block group was statistically greater than in the shame device group."

• Vagal nerve blockade therapy might be safe for obesity treatment.
• Vagal nerve blockade therapy could result in some weight loss.
• Currently, the efficacy of vagal nerve blockade therapy in obesity treatment might not be significant.

Ikramuddin S, Blackstone R, Brancatisano A, et al. Effect of reversible intermittent intra-abdominal vagal nerve blockade on morbid obesity: The recharge randomized clinical trial. JAMA. 2014; 312(9):915-922.