Clinical features and natural history of ulcerative colitis in Korea.

BACKGROUND

The clinical characteristics of ulcerative colitis (UC) in Asian populations have not been well characterized. We therefore investigated the clinical features and natural history of UC in Korea.

METHODS

We retrospectively analyzed 304 Korean patients with UC first diagnosed at the Asan Medical Center between June 1989 and August 2005.

RESULTS

The male-to-female ratio of the patients was 0.94:1, and their median age at diagnosis was 40.0 years (range, 12-72 years). At diagnosis, proctitis was noted in 134 patients (44.1%), left-sided colitis in 69 patients (22.7%), and extensive colitis in 101 patients (33.2%). Disease activity at diagnosis was mild in 149 patients (49.0%), moderate in 125 patients (41.1%), and severe in 26 patients (8.6%). In addition, 4 asymptomatic patients (1.3%) were detected as a result of a screening colonoscopy. Clinical remission after the first attack was documented in 97.4% of patients. The cumulative relapse rate after 1, 5, and 10 years was 30.2%, 72.0%, and 88.4%, respectively. The cumulative risk of proximal extension in patients with proctitis or left-sided colitis was 33.0% after 5 years and 44.5% after 10 years. The cumulative probability of colectomy was 2.0% after 1 year, 2.8% after 3 years, and 3.3% after 5 to 15 years. The cumulative survival rate after 1, 5, and 10 years was 100%, 99.4%, and 97.4%, respectively.

CONCLUSIONS

The clinical features of Korean UC patients at diagnosis are similar to those of Westerners. However, UC in Koreans may have a milder course than in Westerners, as indicated by the lower rate of colectomy among Koreans.