Background & aims: Crohn's disease (CD) confined to the colon and rectum is an increasing clinical entity. The aim of this study was to assess the features and clinical course of colorectal CD.
Methods: This was a retrospective cohort study of 507 patients in whom colonic or rectal CD had been diagnosed between 1955 and 1989.
Results: Colonic distribution was segmental in 40%, total in 31%, and left-sided in 26%. Perianal/rectal fistulas occurred in 37%. In patients who attained clinical remission, the 5-year cumulative relapse rate after diagnosis was 67% (95% confidence interval [CI], 62-72). At the initial presentation of CD, the frequency of major surgery decreased from 24% to 14% (P < 0.005) over time. Still, the overall long-term probability of major surgery after 10 years was unaltered (49% vs. 47%). The presence of fistulas increased the probability of surgical resection (relative risk [RR], 1.7 [95% CI, 1.3-2.2]), whereas left-sided disease was associated with a decrease (RR, 0.6 [95% CI, 0.4-0.8]). Twenty-four percent of the patients developed inflammation in the small bowel. The cumulative risk for a permanent ileostomy was 25% (95% CI, 21-29) 10 years after diagnosis.
Conclusions: Colorectal CD is an increasing entity carrying substantial morbidity. Half of the patients will undergo surgical resection within the first 10 years, and half of those will ultimately undergo ileostomy. Changed management at diagnosis has not affected the long-term probability of resection.