Long-term Prognosis of Ulcerative Colitis and its Temporal Change Between 1977 and 2013: A Hospital-based Cohort Study from Korea

Background and aims: No previous large-scale studies have evaluated the prognosis of ulcerative colitis (UC) over a period of three decades in a non-Caucasian population. The aims of this study were to update the current information on the natural course of UC in a sizable cohort of Korean patients and to evaluate changes in the treatment paradigms and prognosis of UC over time. Methods: We retrospectively analyzed 2802 Korean UC patients who visited Asan Medical Center. We divided the study subjects into three groups based on the year of diagnosis (cohort 1: 19771999; cohort 2: 2000-2006; and cohort 3: 2007-2013). Results: Five-year cumulative probabilities of prescription of thiopurines (azathioprine or 6-mercaptopurine) and anti-tumor necrosis factor (anti-TNF) agents were 4.1% and 0.0%, respectively, in cohort 1 and 27.9% and 12.7%, respectively, in cohort 3 (P < 0.001). A total of 209 patients (7.5%) underwent colectomy, producing cumulative probabilities of colectomy at 10, 20 and 30 years after diagnosis of 7.8%, 14.2% and 21.3%, respectively. The cumulative probability of colectomy was especially low in patients first diagnosed at our center: 3.1% at 10 years and 4.5% at 20 years. Moreover, the cumulative probability of colectomy decreased significantly over the last 30 years (P = 0.039). Conclusion: Thiopurines and anti-TNF agents are used increasingly more frequently and earlier, while the colectomy rate has decreased over the last 30 years in Korean patients with UC. Korean UC patients may have a better clinical course than Western cases, as indicated by a lower colectomy rate.