S805 Predictors of Complicated Diverticulitis in Obese Patients With and Without Prior Bariatric Surgery: A 5-Year National Inpatient Sample Analysis

Introduction: Obesity is a known risk factor for diverticular disease. While bariatric surgery (BS) confers metabolic benefits, its impact on the severity of diverticulitis, particularly complications such as abscess, perforation, and obstruction, remains unclear. This study aimed to identify predictors of complicated diverticulitis in obese patients and assess whether prior BS modifies this risk. Methods: We performed a retrospective analysis of the National Inpatient Sample (2016–2020), identifying adults (≥18 years) with acute diverticulitis and obesity using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes. Severe cases were defined by presence of perforation, abscess, fistula, peritonitis, or obstruction. Multivariable logistic regression was used to assess predictors of complicated disease, adjusting for age, sex, race, smoking, comorbidities, insurance, income, and hospital factors. An interaction term evaluated whether BS modified the risk among patients with high comorbidity burden. Results: Among 45,238 obese patients with diverticulitis, 9,946 (22.0%) had complicated disease. A total of 5,515 (12.2%) had prior BS. Complication rates were lower in the BS group (17.6%) than non-BS patients (22.7%, P < 0.001). Independent predictors of complications included older age (per 10 years: adjusted odds ratio [aOR] 1.11, 95% confidence interval [CI]: 1.08–1.15), male sex (aOR 1.23, 95% CI: 1.17–1.30), smoking (aOR 1.34, 95% CI: 1.25–1.43), malnutrition (aOR 1.45, 95% CI: 1.29–1.63), and CKD (aOR 1.29, 95% CI: 1.18–1.41). Prior BS was associated with a lower risk of complications (aOR 0.71, 95% CI: 0.62–0.80). A significant interaction was observed between BS and Charlson Comorbidity Index ≥3 (interaction P = 0.02), suggesting greater benefit of BS in highly comorbid patients (aOR 0.58, 95% CI: 0.46–0.73). Model discrimination was strong (c-statistic = 0.78). Conclusion: In this national cohort, prior bariatric surgery was associated with a significantly lower risk of complicated diverticulitis in obese patients, especially among those with greater comorbidity burden. Traditional risk factors including age, male sex, smoking, malnutrition, and chronic kidney disease remained significant predictors. These findings suggest that bariatric surgery may offer protective effects beyond metabolic health, informing future risk stratification and management of diverticulitis.