Int J Obes (Lond). 2016 Dec;40(12):1891-1898. doi: 10.1038/ijo.2016.159. Epub 2016 Sep 16.

Closed-loop gastric electrical stimulation versus laparoscopic adjustable gastric band for the treatment of obesity: a randomized 12-month multicenter study.

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Obesity is a disease that is growing worldwide due to changes in environmental factors1. The societal changes that have led to less opportunities for exercise and less availability of good food choices have caused a huge growth in the percentage of obese individuals, currently reported at 38% of the population in the United States1.

The abiliti® therapy system presented in this paper is a multi-tiered approach which is able to counteract these environmental factors with both gastric electrical stimulation providing a sensation of early satiety, and multiple onboard sensors (an intake and exercise sensor) which aid with behavior modification. As shown in Figure 1, the system is a closed-loop gastric electrical stimulation (CLGES) therapy, where food is detected entering the stomach and stimulation is then delivered to the anterior lessor curvature at the “goose foot” where the nerve of Latarjet terminates in three main branches. The electrical stimulation parameters were tailored to the individual at implant and follow-up visits using the external programmer, in order to produce the desired fullness symptoms through activation of vagal afferents.




Figure 1. Diagram of the close-loop feedback system, where detection of food entering the stomach triggers delivery of gastric electrical stimulation at the anterior lessor curvature where the vagal nerve innervates the stomach.


Figure 2 illustrates the type of data that the patient was able to see on the external programmer during follow-ups in the clinic. Both intake and exercise data is collected 24/7. Not only the stimulation parameters are tailored to the patient, also the typical meal schedule of the patient is determined in order to create times when eating is allowed or disallowed (white areas and grey areas respectively in the top two bars of Figure 2). The stimulation is designed to provide a higher level of symptoms during the disallowed times in order to discouraged eating during disallowed time and establish a regular pattern of eating. The green bars show the participants exercise level. A published retrospective analysis of the stored sensor data by Bussetto et al.2 shows that during the 12 month study both eating and exercise behavior was improved, suggesting that the sensor data feedback had a positive effect on behavior.



Figure 2. The food intake sensor and activity sensor provide 24 hour a day monitoring of patient habits, including meal times, physical activity, and sleep patterns.


The publication reports on the first randomized controlled trial comparing the safety and efficacy of two obesity therapy devices. The CLGES therapy was shown to be non-inferior to the gastric band in terms of a composite endpoint that included efficacy and safety. In addition a comparison of the rate of adverse events over 12 months showed significant advantage of abiliti over the gastric band. (Figure 3.)



Figure 3. Percent of Patients who experienced mild, moderate and severe, or no adverse events, comparing the abiliti (CLGES) to the band group(LAGB).


The excess weight loss at 12 month was 35.1±19.7% for the CLGES group, and 40.0±22.7% for the gastric band group. The CLGES group continued to be observed for weight loss and efficacy out to 18 months, remaining stable at 36.2±22.3 for the patients attending 18 months visit (n = 74 ). Figure 4 presents the 18 month weight loss for all participants in the form of a waterfall plots. In plot A the colors represent the patients status in the study, and in plot B the color of the bar represents the weight loss end point that was met for each patient.



Figure 4. Individual weight-loss at 18 month including all 106 implanted participants. Plot A shows all weight loss color coded according to completion of 18 M therapy. Plot B shows the same weight loss data but color coded according to if the participant met the weight loss endpoint of > 20% EWL, or > 25% EWL.


Although bariatric surgery has been shown to be an effective treatment for weight loss and diabetes management, many patients do not wish to undergo a surgical procedure, despite meeting BMI and comorbidity qualifications. A recent paper surveyed potential candidates for bariatric surgery and found the most common reason for not being interested in surgery was fear of complications from surgery3. This finding emphasizes the importance of new options for obesity treatment that are safer and have less negative side effects than current bariatric surgery, but provide clinically significant and longer term weight loss than traditional and pharmaceutical options. Gastric electrical stimulation (GES) is a reversible surgical option that offers support for long lasting behavioral changes and is less invasive than conventional bariatric surgery options. Further studies to investigate the stability of the weight loss in the long term are needed.

Obesity is a very complex disease, and no single solution will meet the needs of all. Recently the demographics of the participant population, and baseline eating behavior as measured by the TFEQ, were evaluated as potential predictors of weight loss success at one year4. It was found that there were significant predictors of success, including older age and more cognitive restraint as measured by the TFEQ Future studies may control for these factors to determine if weight loss outcome may be further improved.


  1. Bray, G. A., Kim, K. K., Wilding, J. P. H., and on behalf of the World Obesity Federation (2017) Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obesity Reviews, 18: 715-723.
  2. Busetto, L., Torres, A. J., Morales-Conde, S., Alarcón del Agua, I., Moretto, C., Fierabracci, P., Rovera, G., Segato, G., Rubio, M. A. and Favretti, F. (2017), Impact of the feedback provided by a gastric electrical stimulation system on eating behavior and physical activity levels. Obesity, 25: 514-521.
  3. Fung M, Wharton S, Macpherson A, Kuk JL. Receptivity to Bariatric Surgery in Qualified Patients. J Obes 2016.
  4. Alarcon Del Agua I, Socas-Macias M, Busetto L, et al. Post-implant Analysis of Epidemiologic and Eating Behavior Data Related to Weight Loss Effectiveness in Obese Patients Treated with Gastric Electrical Stimulation. Obes Surg 2017; 27:1573.