Association Between Appetite-Regulating Hormonal Levels and Body Composition Among Adults With Pre-operative Bed Undergoing Bariatric Surgery: A Prospective Cohort Study Protocol

Abstract

Introduction: Severe obesity, defined by a body mass index (BMI) of >35 kg/m², is a health concern affecting one in eight individuals worldwide and one in three Canadians (1, 2, 3). Metabolic bariatric surgery (MBS) is a safe and effective treatment that offers long-term success compared to conventional methods like pharmacotherapy and behavioural control. However, post-operative weight regain remains common, particularly among MBS candidates with binge-eating disorder (BED). The objective of this study is to comparatively examine the association of appetite-regulation hormones, namely ghrelin and leptin, with post-laparoscopic sleeve gastrectomy (LSG) and post-Roux-en-Y gastric bypass (RYGB) weight maintenance and binge-eating behaviours among individuals with preoperative BED.

Methods: This is a prospective cohort study to examine changes in ghrelin and leptin levels in adult patients with pre-operative BED undergoing LSG or RYGB. A total of 90 will be recruited from bariatric centers of excellence in Ontario, Canada. Summary statistics and anthropometrics will be measured pre-operatively and at 1, 3-, 6-, 12-, and 24-months post-surgery. Binge eating will be assessed using the Binge Eating Scale (BES).

Anticipated Results: Ghrelin and leptin levels will vary by surgery type, due to RYGB’s association with higher 24-month ghrelin levels than LSG. Lower 12-month post-MBS BES scores will predict lower weight regain 24-months post-MBS. Weight loss is anticipated in both groups, with no significant difference based on surgery type.

Discussion: The study aims to examine the influence of surgery type-specific ghrelin and leptin levels on binge-eating behavior and post-operative weight maintenance. Differences in hormonal regulation and weight regain between LSG and RYGB patients may be correlated, given that RYGB patients are reported to experience more favourable long-term outcomes. Elevated ghrelin levels post-RYGB are paradoxically associated with lower BED symptoms, potentially promoting long-term weight stability. These findings could inform personalized post-operative care strategies and promote long-term hormonal monitoring/therapy.

Conclusion: Understanding the hormonal mechanisms underlying post-MBS weight regain and binge-eating behaviours helps optimize long-term patient outcomes. Long-term research on the stability of ghrelin and leptin levels, and the influences of other appetite-regulating hormones, would provide insight into sustained metabolic changes post-MBS.