Natural history of inflammatory bowel disease in Asia: A follow-up population-based cohort study

Abstract

BACKGROUND AND AIM: Data on the natural history of inflammatory bowel disease (IBD) in population-based setting in Asia are scarce. It is not clear if IBD disease course differs between Asian and Western cohorts. METHODS: In a population-based incident cohort from eight countries in Asia, we identified 259 IBD patients diagnosed between 2011 and 2013, including 158 ulcerative colitis (UC) and 101 Crohn's disease (CD) with a median follow up of 15 months (range, 12-31 months). The risk of disease extent and behaviour change according to the Montreal classification, and probability of medical or surgical therapy were prospectively assessed. RESULTS: Median age at diagnosis was 29 years (Interquartile range, IQR, 20-44) for CD, and 41 years (IQR, 30-54) for UC. At diagnosis, in CD, ileo-colonic disease (51%) and inflammatory behaviour (67%) were the most frequent phenotype. At one year, cumulative probability of behavior change from inflammatory to stricturing or penetrating disease was 18%, and cumulative rate of colectomy was 8%. In CD cumulative probabilities of receiving 5-aminosalicylic acid (5-ASA), corticosteroids, immune-suppressants and anti-tumor necrosis factor therapy were 61%, 43%, 66% and 10%, respectively, at one year. In UC, disease extent at diagnosis was evenly distributed including 31% with proctitis, 37% with left sided disease and 32% with extensive colitis. Disease extension occurred during follow-up in 19% of patients. Cumulative rate of colectomy at one year was 1%. In UC cumulative probabilities of receiving 5-ASA, corticosteroids and immunesuppressants were 91%, 28% and 13%, respectively at one year. There were two mortalities at maximal follow-up from lung carcinoma and severe sepsis. CONCLUSION: In this populationbased follow-up study, clinical presentation and early disease course in Asian IBD patients appear comparable to that of Western patients. Progression to complicated behavior and accelerated use of immunesuppressants is common in CD. Early surgical rate for UC in Asia remains low. Understanding the natural history of IBD in our population can help optimize therapeutic interventions. Reference: SC Ng, et al. Incidence and Phenotype of Inflammatory Bowel Disease, Based on Results from the Asia-Pacific Crohn's and Colitis Epidemiologic Study. Gastroenterology 2013; 145(1):158-165