P277 Clinical features and natural history of patients diagnosed with asymptomatic ulcerative colitis

Abstract

Background: A few ulcerative colitis (UC) patients are diagnosed when they do not have any symptoms related with UC. However, the prevalence of asymptomatic UC patients together with their clinical features and prognosis are not clear yet. Methods: We retrospectively analyzed the data of UC patients from the IBD database of Asan Medical Center and identified UC patients who were asymptomatic at diagnosis. The prevalence of asymptomatic UC cases and the clinical features and prognosis of them compared with matched (1:4) symptomatic UC cases were investigated. Control patients were randomly selected with matching for gender, age at UC diagnosis (±10 years), and year at UC diagnosis (±3 years). Results: A total of 2045 UC patients, who were diagnosed with UC between July 1977 and August 2011 and followed for more than one year after diagnosis were reviewed. Twenty patients (0.9%) without symptoms were incidentally diagnosed with UC during screening colonoscopy. The proportion of male was 80% (n = 16), and their median age at diagnosis was 47 years (range, 34 71 years). At diagnosis, proctitis was noted in 12 (60%), left-sided colitis in 5 (25%), extensive colitis in 0 (0%), and atypical distribution in 3 (15%). The Mayo score at diagnosis was 1 in 14 (70%) and 2 in 6 (30%). Twelve patients (60%) developed symptoms during follow-up (median 3.5 years, range 1.1 13.8 years). The 5-year cumulative probability of developing symptoms was 68.7% (95% confidence interval [CI] 43.8%-93.0%). After diagnosis of UC, oral 5-aminisalicylic acid (ASA) was used in 15 (75%) patients, topical 5-ASA in 17 (85%), and systemic steroids in 6 (30%) for treatment. There were no patients who received topical steroids, azathiopurine, infliximab or who underwent colectomy. Disease extent at diagnosis was significantly different between two groups (P= 0.002) with higher proportion of extensive colitis in symptomatic controls (32% vs. 0%) and more common atypical distribution in asymptomatic cases (15% vs. 1.3%). During follow-up (median 3.5 years for cases vs. median 3.4 years for controls, P = 0.45), the cumulative probability of using steroids was higher in symptomatic controls as compared with asymptomatic cases (hazard ratio 2.6; 95%CI 1.1 5.9; P= 0.03). Conclusions: The prevalence of asymptomatic UC patients was 0.9% in our UC patient cohort. These asymptomatic UC patients appear to show a better prognosis compared with symptomatic UC patients. This study was supported by a grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (A120176).