title: Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn's disease.
abstract: OBJECTIVE
  Recent studies on appendicectomy rates in ulcerative colitis and Crohn's disease have generally not addressed the effect of appendicectomy on disease characteristics. The aims of this study were to compare appendicectomy rates in Australian inflammatory bowel disease patients and matched controls, and to evaluate the effect of prior appendicectomy on disease characteristics.
  
  
  METHODS
  Patients were ascertained from the Brisbane Inflammatory Bowel Disease database. Controls matched for age and sex were randomly selected from the Australian Twin Registry. Disease characteristics included age at diagnosis, disease site, need for immunosuppression, and intestinal resection.
  
  
  RESULTS
  The study confirmed the significant negative association between appendicectomy and ulcerative colitis (odds ratio (OR) 0.23, 95% confidence interval (CI) 0.14-0.38; p<0.0001) and found a similar result for Crohn's disease once the bias of appendicectomy at diagnosis was addressed (OR 0.34, 95% CI 0.23-0.51; p<0.0001). Prior appendicectomy delayed age of presentation for both diseases and was statistically significant for Crohn's disease (p=0.02). In ulcerative colitis, patients with prior appendicectomy had clinically milder disease with reduced requirement for immunosuppression (OR 0.15, 95% CI 0.02-1.15; p=0.04) and proctocolectomy (p=0.02).
  
  
  CONCLUSIONS
  Compared with patients without prior appendicectomy, appendicectomy before diagnosis delays disease onset in ulcerative colitis and Crohn's disease and gives rise to a milder disease phenotype in ulcerative colitis.
authors.affiliation: Department of Gastroenterology, Royal Brisbane Hospital, Brisbane, Australia 4029. Graham_Radford-Smith@health.qld.gov.au
authors.forename: G L
authors.initials: GL
authors.lastname: Radford-Smith
authors.forename: J E
authors.initials: JE
authors.lastname: Edwards
authors.forename: D M
authors.initials: DM
authors.lastname: Purdie
authors.forename: N
authors.initials: N
authors.lastname: Pandeya
authors.forename: M
authors.initials: M
authors.lastname: Watson
authors.forename: N G
authors.initials: NG
authors.lastname: Martin
authors.forename: A
authors.initials: A
authors.lastname: Green
authors.forename: B
authors.initials: B
authors.lastname: Newman
authors.forename: T H J
authors.initials: TH
authors.lastname: Florin
mesh_terms: D000328:Adult; D017668:Age of Onset; D001062:Appendectomy; D001065:Appendix / Q000473:pathology; D016022:Case-Control Studies; D003082:Colectomy; D003093:Colitis, Ulcerative / Q000473:pathology / Q000517:prevention & control* / Q000628:therapy; D003424:Crohn Disease / Q000517:prevention & control* / Q000628:therapy; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D016017:Odds Ratio; D012907:Smoking / Q000009:adverse effects
chemical_list: D007166:Immunosuppressive Agents