Risk of Inflammatory Bowel Disease Following Appendectomy in Adulthood

Wei-Sheng Chung; Sunny Chung; Chung-Y Hsu; Cheng-Li Lin

doi:10.3389/fmed.2021.661752

Risk of Inflammatory Bowel Disease Following Appendectomy in Adulthood

Front Med (Lausanne). 2021 Jun 2:8:661752. doi: 10.3389/fmed.2021.661752. eCollection 2021.

Authors

Wei-Sheng Chung^{1

2

3}, Sunny Chung⁴, Chung-Y Hsu⁵, Cheng-Li Lin^{6

7}

Affiliations

¹ Department of Internal Medicine, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan.
² Department of Health Services Administration, China Medical University, Taichung, Taiwan.
³ Department of Healthcare Administration, Central Taiwan University of Science and Technology, Taichung, Taiwan.
⁴ Department of Chemistry, Point Loma Nazarene University, San Diego, CA, United States.
⁵ Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.
⁶ Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
⁷ College of Medicine, China Medical University, Taichung, Taiwan.

Abstract

Background: The appendix has a complicated immune function, and appendectomy may derange the immune system. Studies on the relationship between appendectomy and subsequent inflammatory bowel disease (IBD) have been inconsistent. We conducted a nationwide cohort study consisting of individuals who underwent appendectomy to evaluate the incidence and risk of ulcerative colitis (UC) and Crohn's disease (CD). Methods: We identified patients aged >20 years who underwent appendectomy between 2000 and 2012 from inpatient claims of the National Health Insurance Research Database (NHIRD) and assigned them to the appendectomy cohort. Then, we randomly selected patients without appendectomy in the NHIRD and assigned them to the comparison cohort in a frequency-matched 1:1 ratio based on sex, age, and index year. We tracked down all participants until IBD diagnosis, death, or the end of 2013. Cox models were used to estimate the hazard ratio (HR), and 95% confidence intervals (CIs) were used to compare the IBD risk between the appendectomy and comparison cohorts. Results: The appendectomy and comparison cohorts in the study consisted of 246 562 patients each. The appendectomy cohort exhibited a 2.23- and 3.48-fold higher risk of UC (adjusted HR = 2.23, 95% CI = 1.59-3.12) and CD (adjusted HR = 3.48, 95% CI = 2.42-4.99), respectively, than did the comparison cohort. UC and CD risks significantly increased in the appendectomy cohort regardless of whether appendicitis was present. Conclusions: Our study suggests that appendectomy increases UC and CD risks irrespective of appendicitis.

Keywords: Crohn's disease; appendectomy; cohort study; inflammatory bowel disease; ulcerative colitis.