S1951 Appendectomy Improves Outcomes in Appendicitis Patients With and Without Ulcerative Colitis: A Nationwide Inpatient Analysis

Introduction: Ulcerative colitis (UC) is a chronic inflammatory bowel disease associated with increased healthcare utilization and surgical complexity. While appendectomy is a common and effective treatment for appendicitis, limited data exist on its impact in patients with coexisting UC. Given concerns about altered immune response and postoperative risk in UC, we aimed to assess whether appendectomy improves hospital outcomes in appendicitis patients with UC and how its effects compare to those without UC. Methods: We conducted a retrospective cohort study using data from the National Inpatient Sample (NIS) from 2016–2019. We identified adult patients hospitalized with a principal diagnosis of appendicitis, excluding those who had undergone colectomy or ileocecectomy. Patients were stratified based on UC status. Multivariable linear and logistic regression models were used to evaluate the effect of appendectomy on 3 key outcomes: length of stay (LOS), total hospital charges (TOTCHG), and in-hospital mortality. Interaction terms were included to assess whether UC status modified the effect of appendectomy on these outcomes. All analyses accounted for demographic variables and hospital characteristics. Results: We identified 141,349 hospitalized adults with appendicitis, including 505 (0.36%) with UC. Compared to non-UC patients, UC patients had worse outcomes: longer length of stay (LOS; 5.01 vs 3.73 days), higher hospital charges ($77,723 vs $62,460), and higher in-hospital mortality (1.2% vs 0.4%, P = 0.008). In multivariable models, appendectomy was linked to shorter LOS and lower charges in both groups. Among UC patients, appendectomy reduced LOS by 2.56 days and charges by $19,738; among non-UC patients, it reduced LOS by 2.19 days and charges by $3,993 (all P < 0.05). Appendectomy significantly lowered overall in-hospital mortality (aOR = 0.19, P < 0.001). Although UC was independently associated with higher mortality, interaction terms showed that appendectomy’s benefits were consistent regardless of UC status. Conclusion: These findings support appendectomy as an effective intervention in appendicitis, including in UC patients. Despite worse baseline outcomes, UC patients saw significant reductions in LOS, charges, and mortality, similar to non-UC patients. This challenges concerns about surgical risk in UC and highlights appendectomy’s value in improving short-term outcomes. Further research is needed to assess long-term results and post-discharge complications in UC patients.