LB804 - The Effect of Appendectomy on the Clinical Course of Ulcerative Colitis: Results of an International Randomized Controlled Trial

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Purpose/Background: Emerging evidence indicates an immunomodulatory role of the appendix in ulcerative colitis (UC). Previous studies suggested a beneficial effect of appendectomy in inducing and maintaining remission. Therefore, appendectomy might be considered as a potentially therapeutic intervention in UC. The aim of this randomized controlled superiority trial was to evaluate the efficacy of appendectomy in maintaining remission in UC patients.

Methods/Interventions: Patients ≥18 years with established UC in complete clinical and endoscopic remission (defined as Mayo score < 3 with endoscopic subscore of 0 or 1) after receiving medical treatment for disease relapse within 12 months prior to randomization, were enrolled in the Netherlands and United Kingdom. Patients were randomized 1:1 to undergo appendectomy (intervention group) or continue maintenance medical therapy (control group). The primary outcome was the one-year UC relapse rate, defined as a total Mayo-score score ≥5 with endoscopic subscore of 2 or 3. Secondary outcomes included time to first relapse, number of relapses per patient, disease activity, number of colectomies, medication use and health-related quality of life.

Results/Outcomes: Between September 2012 and September 2022, 198 patients were enrolled with a median age of 41 (IQR 33-52) years, and 112 (56.6%) were females. The median disease duration at randomization was 5.1 (IQR 1.7-11.3) years, with the majority treated for proctitis (38.9%) or left-sided colitis (35.4%). There were no significant differences between the groups regarding patient and disease characteristics. The one-year UC relapse rate was significantly lower in the appendectomy group compared to the control group (35.4% vs 54.5%; p=0.007). The relapse-free survival differed significantly between the appendectomy and the control group (p=0.028; figure 1.). In the appendectomy group, there was a decreased escalation of medical therapies with a significantly higher percentage of patients not using medication at 12 months, compared to the control group (23.4% vs 7.6%, respectively; p=0.003). Analyses of the other secondary outcomes are scheduled for March 2024.

Conclusion/Discussion: Appendectomy is superior to standard medical therapy alone in maintaining remission in UC patients.