Differences in disease characteristics and treatment exposures between paediatric and adult‐onset inflammatory bowel disease using a registry‐based cohort.

Summary: Background: Previous studies highlighted a more extensive phenotype for paediatric‐onset than adult‐onset inflammatory bowel disease (IBD). However, most lacked long‐term follow‐up, and some were conducted before the era of biologics. Aims: The aim of this study is to compare disease characteristics and treatment exposures between paediatric‐onset and adult‐onset IBD. Methods: From a registry that periodically and uniformly retrieves demographics, disease characteristics/phenotype, and treatments, we compared the characteristics of paediatric‐onset (diagnosed at ≥6 and <18 years) and adult‐onset IBD, diagnosed during 2000–2022 and with ≥12 months follow‐up. Results: Of the 2837 patients with Crohn's disease and 1332 with ulcerative colitis, 3316 had adult‐onset and 853 paediatric‐onset IBD. The median follow‐up was 6 years. Patients with paediatric‐onset presented with more extensive disease and received more intensified therapies, including biologics and JAK inhibitors than those with adult‐onset IBD. Paediatric‐onset ulcerative colitis showed a higher prevalence of E3 extensive colitis including pancolitis and a greater requirement for systemic steroids, immunomodulators, and biologics than adult‐onset ulcerative colitis. Paediatric‐onset versus adult‐onset Crohn's disease exhibited greater L3 ileocolonic involvement and perianal disease phenotype, and higher exposure to immunomodulators and biologics. Kaplan–Meier curve and Cox proportional hazards analyses showed significantly lower 15‐year biologic‐free survival from diagnosis among those with paediatric‐onset IBD than with adult‐onset IBD (p = <0.001), indicating greater and earlier use of biologics in the former. Conclusions: Paediatric‐onset presents with more extensive disease with higher exposures to immunomodulators and biologic therapies than adult‐onset IBD. [ABSTRACT FROM AUTHOR]