# Poster Session II - A285 RISK OF COLECTOMY AFTER APPENDECTOMY IN ESTABLISHED ULCERATIVE COLITIS: A SYSTEMIC REVIEW AND META-ANALYSIS

## TL;DR

This study finds no evidence that appendectomy reduces the risk of colectomy in people with established ulcerative colitis.

## Contribution

The first systematic review and meta-analysis evaluating appendectomy's effect on colectomy risk in established UC.

## Key findings

- No significant association found between appendectomy and reduced colectomy risk in UC patients.
- High heterogeneity among studies limited the strength of conclusions.
- Subgroup analyses by disease activity and UC extent were inconclusive due to data variability.

## Abstract

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by relapsing-remitting inflammation of the colon and rectum. Current management focuses on inducing and maintaining clinical and endoscopic remission to prevent complications like colectomy. Recent studies suggest the appendix may play an immunomodulatory role. Several studies have suggested those with appendectomy may be at lower risk of developing UC. Preliminary studies indicate there may even be a role for appendectomy in those with established UC, but its clinical effectiveness in established UC remains unclear.

This systematic review and meta-analysis aims to evaluate the association of appendectomy and longer-term risk of colectomy in patients with established UC.

We searched MEDLINE, EMBASE, and Cochrane Library from inception without date restrictions, including randomized controlled trials and observational studies reporting colectomy rates in patients with established UC who had appendectomy after their diagnosis of UC compared to patients without appendectomy. Primary outcome was rate of colectomy after appendectomy. Secondary outcomes included flare frequency, treatment response, need for steroids or change in medications. Data were synthesized using random-effects meta-analysis, with heterogeneity assessed via I2 and chi-squared tests. Study quality was evaluated using the Newcastle-Ottawa Scale and Cochrane Risk of Bias 2 tools.

We included 10 studies (1 randomized controlled trial (RCT) and 9 observational studies) (Table 1) from 1120 citations. Seven studies were eligible for inclusion with the meta-analysis, with significant heterogeneity (I2 = 78.02%, p = 0.0001). There was no significant association between appendectomy and odds of colectomy (OR 1.265, 95% CI 0.588–2.721, p = 0.547) (Table 2). Subgroup analyses by disease activity (active vs. remission) and UC extent were limited by data variability.

Current evidence does not suggest a therapeutic benefit for appendectomy to lower rates of colectomy in those with established UC. Further data is needed to understand its role for induction and maintenance of remission.

A285 Table 1: Baseline characteristics of the included studies

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