Objectives: Appendectomy has been shown to protect against the development of ulcerative colitis. The objective of this study was to examine the effect of appendectomy on the clinical features and natural history of colitis.
Methods: A total of 259 consecutive adults patients with ulcerative colitis were studied. Of the patients, 20 had undergone appendectomy (12 before onset of colitis and eight after diagnosis).
Results: The frequency of appendectomy was significantly less than in a group of 280 controls, which comprised partners of the patients and a group from the community (OR = 0.25; 95% CI = 0.14-0.44). This was even more significant if only the 12 patients who underwent surgery before the onset of colitis were considered (OR = 0.15; 95% CI = 0.07-0.28). Patients with prior appendectomy developed symptoms of ulcerative colitis for the first time at a significantly later age than those without appendectomy (42.5 +/- 6.5 vs 32.1 +/- 0.8 yr; p < 0.01) or those who had appendectomy after the onset of colitis (24.6 +/- 3.4 yr; p < 0.05). Appendectomy did not influence disease extent, need for immunosuppressive treatment with azathioprine or 6-mercaptopurine (as a marker of resistant disease), or the likelihood of colectomy. Five patients in the appendectomy group had clinical evidence of primary sclerosing cholangitis (25%). This was more common than in those without appendectomy (8%; OR = 4.09; 95% CI = 1.04-13.60).
Conclusions: These results indicate that although appendectomy may delay onset of colitis, it does not influence its course. However, it is associated with the development of primary sclerosing cholangitis. Appendectomy is unlikely to be of benefit in established ulcerative colitis.