S1952 Postoperative Complications After Appendectomy in Ulcerative Colitis: A National Inpatient Cohort Analysis

Introduction: While appendectomy typically has low risk of complications, patients with ulcerative colitis (UC) may have increased odds of adverse postoperative outcomes due to chronic inflammation, immunosuppressive therapy, and malnutrition. Despite these concerns, no large-scale U.S. study has assessed whether UC independently contributes to greater odds of complications or mortality following appendectomy. We evaluated appendectomy outcomes in UC patients using national inpatient data. Methods: We conducted a retrospective cohort study using the 2018–2021 National Inpatient Sample. Adults (≥18 years) undergoing appendectomy were identified with International Classification of Diseases-10 codes (0DTJ0ZZ, 0DTJ4ZZ, 0DTJ8ZZ); UC was identified via K51.x codes. Primary and secondary outcomes were postoperative complications and in-hospital mortality. Complications were categorized by system. Multivariable logistic regression adjusted for age, sex, race/ethnicity, and income. Due to unavailable present-on-admission flags, all complications were assumed postoperative. National estimates were generated using NIS sampling weights. Results: Among 140,836 appendectomy hospitalizations, 433 (0.3%) involved UC. UC was independently associated with higher odds of any complication (aOR 1.33, 95% CI 1.07–1.65, P = 0.01), compared to non-UC patients. A non-significant increase in odds of in-hospital mortality was observed (aOR 2.23, 95% CI 0.91–5.43, P = 0.078). UC patients had significantly higher odds of sepsis (aOR 1.88, P = 0.004), postop delirium (aOR 3.67, P = 0.002), and malnutrition or weight loss (aOR 3.53, P < 0.001). Non-significant trends were noted for pneumonia, ileus, AKI and abscess. Female sex was associated with lower odds of complications and mortality compared to males (aORs 0.73 and 0.75, respectively, P < 0.001). Each year of age increased odds of complications by 3% and mortality by 5% (P < 0.001). Higher income quartile was associated with lower odds of both outcomes. African American patients had higher odds of complications (aOR 1.49) and mortality (aOR 1.77, P < 0.001) compared to non-AA. Conclusion: UC is associated with significantly greater odds of postop complications following appendectomy, particularly for sepsis, delirium, and malnutrition. These findings suggest the importance of tailored perioperative strategies in UC, including nutritional support and multidisciplinary planning. Despite limitations of administrative data, this study underscores the importance of individualized surgical planning in UC populations.