Appendicectomy has no beneficial effect on admission rates in patients with ulcerative colitis.

BACKGROUND AND AIMS Those who have had an appendicectomy have a reduced risk of developing ulcerative colitis. However, the effect of appendicectomy on disease activity in patients with ulcerative colitis has not been established. METHODS We used the Danish National Patient Registry to identify all incident cases of ulcerative colitis in Denmark during the period 1981 to 1999. Of these, 202 had an appendicectomy after their first admission with ulcerative colitis. In these patients, we compared the incidence rate of hospitalisations with ulcerative colitis as first diagnosis during the period between the onset of ulcerative colitis and appendicectomy, with the rate of such hospitalisations after appendicectomy. To adjust for the clinical course of ulcerative colitis unrelated to appendicectomy, we extracted a reference cohort (n = 808), matched to the index subjects with respect to age, sex, and year of first admission, but with an intact appendix. RESULTS The rate of admission with ulcerative colitis as first diagnosis decreased by 47% after appendicectomy (rate ratio 0.53 (95% confidence interval (CI) 0.36-0.80)). However, the reference cohort showed a similar decline in admission rate (rate ratio 0.51). Thus appendicectomy had no apparent beneficial effect on admission rate after adjustment for the clinical course of disease unrelated to appendicectomy (adjusted rate ratio 1.05 (95% CI 0.67-1.67)). CONCLUSIONS Appendicectomy had no significant beneficial effect on admission rates in patients with ulcerative colitis.