Prevalence, risk factors, and clinical outcomes of extraintestinal manifestations in inflammatory bowel disease: a population-based study in china

BACKGROUND AND AIMS: Extraintestinal manifestations (EIMs) complicate the management of inflammatory bowel disease, and their epidemiology in Chinese patients remains unclear. We aimed to determine their prevalence and examine associated risk factors and clinical outcomes. METHODS: We conducted a cross-sectional study of over 44 000 patients of all ages in eastern China using data from the China National Healthcare Big Data (East) Center (2019-2024). We examined diverse EIMs (articular, skin, ocular, and oral manifestations, primary sclerosing cholangitis, and autoimmune hepatitis) and compared clinical characteristics of patients with and without EIMs using multivariable logistic regression. RESULTS: The overall prevalence of EIMs was higher in ulcerative colitis (20.46%) than in Crohn's disease (14.64%). Among pediatric patients (<18 years), EIMs were more frequent in Crohn's disease (13.08%) than in ulcerative colitis (10.18%). EIM prevalence increased progressively across the four age groups (<18, 18-40, 40-65, and >65 years; P < 0.001). Risk factors included older age (P < 0.001), female sex in ulcerative colitis (P = 0.002), and pancolitis (P = 0.041), whereas in pediatric patients, EIMs were linked to younger age (P = 0.015). EIMs were also associated with corticosteroid use (P < 0.001), all-cause hospitalization (P = 0.044 in Crohn's disease; P < 0.001 in ulcerative colitis), and other adverse clinical outcomes. A total of 1.9% of Crohn's disease and 3.5% of ulcerative colitis patients had multiple EIMs, most commonly involving peripheral arthritis. CONCLUSION: This first large-scale study of Chinese inflammatory bowel disease patients evaluates EIMs, revealing age-specific and population-specific patterns that inform risk identification and individualized management.