Appendectomy and the Risk of Colectomy in Ulcerative Colitis: A National Cohort Study

Research output: Contribution to journalArticle


  • Pär Myrelid
  • Kalle Landerholm
  • Caroline Nordenvall
  • Thomas D Pinkney
  • Roland E Andersson

Colleges, School and Institutes

External organisations

  • Department of Surgery, County Council of Östergötland, Linköping, Sweden.
  • Department of Surgery, Colorectal Unit, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
  • Center for Digestive Disease, Division of Coloproctology, Karolinska University Hospital, Stockholm, Sweden.
  • Academic Department of Surgery, Division of Cancer Sciences, University of Birmingham, Birmingham, UK.
  • Department of Surgery, County Hospital Ryhov, Jönköping, Sweden.


OBJECTIVES: Ulcerative colitis (UC) is a chronic inflammatory disease usually responding well to anti-inflammatory drugs but many patients will still need colectomy. Appendectomy is associated with a lower risk of later developing UC. We aimed to assess the longitudinal relationship between appendectomy, appendicitis, and disease course in UC patients.

METHODS: A national cohort of UC patients with a diagnosis in 1964-2010 was identified from the Swedish National Patient Register that also provided information regarding appendicitis and/or appendectomy before or after the UC diagnosis. The risk for colectomy and UC-related hospital admissions was evaluated.

RESULTS: Among 63,711 UC patients, 2,143 had appendectomy and 7,690 underwent colectomy. Appendectomy for appendicitis before 20 years of age and for non-appendicitis at all ages before UC diagnosis was associated with a lower risk of colectomy (hazard ratio (HR) 0.44, 0.27-0.72 and HR 0.62, 0.43-0.90, respectively), and fewer hospital admissions (incidence rate ratio (IRR) 0.68, 95% confidence interval (CI) 0.64-0.73 and IRR 0.54, 0.47-0.63, respectively). Appendectomy for appendicitis after the UC diagnosis was associated with a higher risk of colectomy (HR 1.56, 1.20-2.03), whereas no such association was found for other pathology (HR 1.40, 0.79-2.47).

CONCLUSIONS: Appendectomy early in life and before developing UC is associated with a lower risk of colectomy as well as UC-related hospital admissions. Appendectomy for appendicitis after established UC appears associated with a worse disease course, with an increased rate of subsequent colectomy.


Original languageEnglish
Pages (from-to)1311-1319
Number of pages9
JournalThe American Journal of Gastroenterology
Issue number8
Early online date27 Jun 2017
Publication statusPublished - Aug 2017


  • Adult, Age Factors, Aged, Appendectomy, Cohort Studies, Colectomy, Colitis, Ulcerative, Disease Progression, Female, Humans, Male, Middle Aged, Patient Admission, Protective Factors, Registries, Risk Factors, Young Adult, Journal Article