The nexus between appendicitis and chronic inflammatory bowel diseases: Unraveling an intriguing association

Appendicitis is 1 of the most frequent diseases worldwide. In general, it is treated with appendectomy, which, in almost all cases, leads to the healing of the disease and averts acute complications. However, only limited data regarding long-term sequalae, including inflammatory bowel diseases following appendicitis are available. We therefore investigated the association between appendicitis and both Crohn disease (CD) and ulcerative colitis (UC). The present study included 23,991 patients with a history of appendicitis and 23,991 that did not have such a history. Patients were identified within the Disease Analyzer (IQVIA) database in Germany between 2010 and 2020. After a follow-up period of up to 10 years, 0.74% of patients with a history of appendicitis and 0.45% of those in the nonappendicitis cohort were diagnosed with CD (P < .001). Our regression analysis revealed a robust and statistically significant association between appendicitis and the incidence of CD in the entire study population (Hazard ratio: 1.82; 95% confidence interval [CI]: 1.31-2.53). Importantly, this association remained largely consistent across all age groups and both genders. In contrast, no statistically significant link was observed between appendicitis and the subsequent development of UC (Hazard ratio: 1.24; 95% CI: 0.90-1.71). The present study presents novel data from a large cohort of outpatients in Germany, providing strong evidence for an association between appendicitis and the development of CD (but not UC). These findings contribute to the existing body of literature and may facilitate the recognition of appendicitis as a risk factor for the development of chronic inflammatory bowel diseases.