Appendectomy Protects Against Inflammatory Bowel Disease

Laurie Barclay, MD

November 15, 2002

Nov. 15, 2002 — Appendectomy may protect against inflammatory bowel disease (IBD) with respect to time of onset and severity of disease, according to a study comparing patients with community age-matched controls which was reported in the December issue of Gut.

"Compared with patients without prior appendectomy, appendectomy before diagnosis delays disease onset in ulcerative colitis and Crohn's disease and gives rise to a milder disease phenotype in ulcerative colitis," write G. L. Radford-Smith, from Royal Brisbane Hospital in Australia, and colleagues.

The investigators compared 307 patients with ulcerative colitis and 335 patients with Crohn's disease culled from the Brisbane Inflammatory Bowel Disease database with randomly selected, age- and sex-matched controls from the Australian Twin Registry.

Appendectomy was associated with decreased risk of ulcerative colitis (odds ratio [OR], 0.23, 95% confidence interval [CI], 0.14–0.38; P<.0001). After adjustments for the bias of appendectomy at diagnosis, there was a similar result for Crohn's disease (OR, 0.34; 95% CI, 0.23–0.51; P<.0001).

History of appendectomy delayed the age of presentation in both diseases (P=.02 for Crohn's disease). In ulcerative colitis, patients with history of appendectomy had clinically less severe disease and were less likely to require immunosuppression (OR, 0.15; 95% CI, 0.02–1.15; P=.04) and none required proctocolectomy compared with 21% in the control group (P=.02). These relationships were more pronounced in patients who had appendectomy before age 20 years.

"Adjustment for smoking status did not weaken the negative associations between either ulcerative colitis or Crohn's disease and previous appendectomy," the authors write. "These results are consistent with the hypothesis that the appendix contributes to the development and maintenance of the gut immune system, as suggested in animal models, but does not exclude an inverse relationship between appendicitis (and/or mesenteric adenitis) and IBD."

Gut. 2002;51:808-813

Reviewed by Gary D. Vogin, MD


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