[Relapse rates of ulcerative colitis in remission and factors related to relapse].

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with heterogeneous clinical features. Data on the disease course and prognosis of UC patients who have been regularly treated are lacking. We aimed to investigate relapse rates of UC in remission and factors related to relapse.We retrospectively analyzed clinical courses of 84 patients (43 males, median age 43 years, ranged 20-73 years) diagnosed as UC at Ajou University Hospital between January 1997 and December 2005 based on clinical, endoscopic and pathologic findings, and who were regularly followed for at least one year after the remission.Study subjects consisted of 32 proctitis (38%), 21 left-sided colitis (25%), and 31 subtotal or total colitis (37%). Of 84 patients, relapse was observed in 52 patients (62%) during the follow-up period (ranged 1-9 years). The relapse rate was 24%, 41%, 51%, 65%, 71%, and 79% at 1 year, 2 years, 3 years, 4 years, 5 years and 6 years, respectively. Among sex, age, hemoglobin, ESR, and the extent of disease on admission, decrease of hemoglobin level was the only independent factor related to relapse (odds ratio=2.67, 95% CI (1.32-5.42), p<0.01).In Korea, relapse of UC in remission is not rare. Decrease of hemoglobin level is an independent risk factor related to its relapse, while the extent of disease is not.