Clinical Features and Natural History of Patients Diagnosed With Asymptomatic Ulcerative Colitis

Abstract

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. 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, A total of 2045 UC patients, who were diagnosed with UC between July 1977 and August 2011 and followed for more than one year were reviewed. Nineteen patients (0.9%) without symptoms were incidentally diagnosed with UC during screening colonoscopy. The proportion of male patients was 78.9% (n = 15), and their median age at diagnosis was 47 years (range, 34-71 years). At diagnosis, proctitis was noted in 10 patients (52.6%), left-sided colitis in 5 patients (26.3%), extensive colitis in 3 patients (15.8%), and atypical distribution in 1 patient (5.3%). The Mayo score at diagnosis was 1 in 13 patients (68.4%) and 2 in 6 patients (31.6%). The 5- year cumulative probability of developing symptoms was 66.5% (95% confidence interval [CI] 40.8%-93.1%). During follow-up (median 3.7 years vs. 3.7 years, P = 0.96), the proportion of using corticosteroids (31.6% vs. 56.6%, P = 0.07), azathioprine (0% vs. 28.9%), and infliximab (0% vs. 5.3%) together with colectomy rate (0% vs. 7.9%) were comparable between 19 asymptomatic patients and 76 matched symptomatic patients. The cumulative probability of using corticosteroids showed a lower tendency (hazard ratio 0.43; 95% CI 0.18-1.04; P = 0.06) in asymptomatic patients compared with symptomatic patients. The prevalence of asymptomatic UC patients was 0.9% in our hospital-based study. These asymptomatic UC patients appear to show a better prognosis compared with symptomatic UC patients.