S1094 Inpatient Outcomes in Irritable Bowel Syndrome With Comorbid Obesity: A National Cohort Study

Introduction: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder often complicated by systemic comorbidities, including obesity. Obesity may affect IBS-related outcomes through alterations in gut motility, low-grade inflammation, and neuroendocrine signaling. This study aimed to evaluate inpatient outcomes in hospitalized adults with IBS, comparing those with and without comorbid obesity. Methods: We conducted a retrospective cohort analysis using the National Inpatient Sample (NIS) from 2016 to 2020. Adult patients aged 18 years and older with a diagnosis of IBS (International Classification of Diseases [ICD]-10 codes K58.0–K58.9) listed among the first 10 discharge diagnoses were included. Comorbid obesity was identified using ICD-10 codes E66.0–E66.9. Outcomes included inpatient mortality, length of stay (LOS), total hospital cost, bowel obstruction, chronic abdominal pain, constipation, psychiatric comorbidities, and electrolyte derangements. Multivariable logistic regression models were used to evaluate associations, adjusting for age, sex, race, and Charlson Comorbidity Index. Hospital cost was analyzed using a generalized linear model with a gamma distribution and log link, adjusted to 2020 United States dollars using the Consumer Price Index. Results: Among 859,685 hospitalized patients with IBS, 151,085 (17.6 percent) had comorbid obesity. Among hospitalized IBS patients, those with comorbid obesity demonstrated significantly lower odds of in-hospital mortality (0.2% vs 0.4%; OR: 0.61, 95% CI: 0.45–0.83) and shorter LOS (3.6 vs 3.8 days; OR: 0.94, 95% CI: 0.93–0.95), but incurred higher hospital costs ($12,943.7 vs $11,458.8; OR: 1.16, 95% CI: 1.15–1.18). They had reduced odds of bowel obstruction (OR: 0.80, 95% CI: 0.63–1.00), chronic abdominal pain (OR: 0.69, 95% CI: 0.61–0.78), constipation (OR: 0.73, 95% CI: 0.68–0.77), and electrolyte derangements (OR: 0.72, 95% CI: 0.69–0.74). However, they were more likely to have psychiatric comorbidities (OR: 1.18, 95% CI: 1.14–1.21). Conclusion: Hospitalized patients with IBS and comorbid obesity had lower inpatient mortality, shorter length of stay, and fewer complications including bowel obstruction and electrolyte abnormalities, despite higher hospitalization costs and a greater burden of psychiatric comorbidities. These findings warrant further study to clarify the clinical implications of obesity in this population.