RT Journal Article SR Electronic T1 Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn’s disease JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 808 OP 813 DO 10.1136/gut.51.6.808 VO 51 IS 6 A1 G L Radford-Smith A1 J E Edwards A1 D M Purdie A1 N Pandeya A1 M Watson A1 N G Martin A1 A Green A1 B Newman A1 T H J Florin YR 2002 UL http://gut.bmj.com/content/51/6/808.abstract AB Background and aims: 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.