S1206 Bloating Symptoms Are Associated With Low Muscle Mass: A Retrospective Automated Analysis of Abdominal CT Scans

Introduction: Bloating and abdominal distension are common gastrointestinal complaints. While abdominal wall muscle contraction facilitates accommodation of gas in healthy individuals, it remains unclear whether low muscle mass influences this accommodation capacity. Abdominal computed tomography (CT) scans performed for routine clinical indications can be automatically analyzed with artificial intelligence (AI) tools to screen patients for sarcopenia. We hypothesized that pre-existing CT scans can be used to evaluate the frequency of sarcopenia in patients with bloating as compared to controls without bloating. Methods: In a retrospective study of patients over 18 years old who received an abdominal CT scan between 2014 and 2018, groups were identified by International Classification of Diseases-codes in a ‘bloating’, ‘IBS without bloating’ and a ‘healthy controls’ group, matched for age, sex and body mass index (BMI). Demographics and medical history were collected from electronic health records. CT scans were used to measure muscle area and density at the L3 level with an open-source AI tool (Comp2Comp, Stanford). Sarcopenia was defined as a low skeletal muscle index (SMI). Statistical analysis was performed with Python using Pearson chi squared and unpaired t-test, P < 0.05 was regarded as significant. Results: A total of 2064 patients were included (mean age 55 years old, 74% female, mean BMI 27). There were significantly higher rates of atopic disorders (asthma 28% vs 13%; allergic rhinitis 26% vs 10%; atopic dermatitis 3% vs 1%; urticaria 9% vs 3%), collagen vascular disorders (Ehlers-Danlos syndrome and hypermobility 1% vs 0%; systemic lupus erythematosus 3% vs 1%; rheumatoid arthritis 5% vs 2%) and disorders of gut-brain interaction (functional dyspepsia 25% vs 5%; gastroparesis 9% vs 1%) in the bloating vs control group, respectively. There were significant differences in the muscle area and density between the 3 groups, with higher frequency of sarcopenia in the bloating vs IBS vs control groups (7.7% vs 4.5 vs 3.5%). After stratification by age and sex, this difference was significant between the bloating and control group in patients <65 years old (5.9% vs 1.1%) and in men (16.7% vs 3.9%). Conclusion: Patients with bloating were more likely to have low abdominal muscle mass, with higher rates of sarcopenia in patients below the age of 65 years, as well as in men. Skeletal muscle mass evaluation identifies a subgroup of bloating patients who may benefit from strengthening of the abdominal wall muscles in their management. A prospective clinical trial is needed to further evaluate these findings.