Phenotypic Presentation of Pediatric Inflammatory Bowel Disease Through 4 Decades: The Pediatric NorDIBD Cohort

INTRODUCTION: The incidence of pediatric inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), is increasing worldwide. Thus, a thorough understanding of the development and presentation of pediatric IBD is essential. This study aims to establish and characterize a comprehensive population-based cohort of all patients with pediatric IBD in the North Denmark Region spanning 4 decades. METHODS: We identified all children (n = 468) diagnosed with IBD in the North Denmark Region (589,936 inhabitants) during 1978-2020, establishing the Pediatric NorDIBD cohort. Patient characteristics were manually gathered from medical records. We examined developments in incidence, disease presentation, and family history of IBD over time. RESULTS: A total of 244 children with UC and 224 children with CD were diagnosed during 1978-2020. Incidence rate of pediatric IBD had increased 272%. The proportion of CD had increased. The median age at diagnosis was 15.4 years for both UC and CD and increased over time. In UC, the proportions of children diagnosed with pancolitis increased over time. For CD, most children were diagnosed with ileocolonic (39.3%) or colonic (40.2%) disease, and the proportion presenting with ileocolonic and penetrating CD increased over time. The 13% of patients who had a first-degree relative with IBD were younger at diagnosis. DISCUSSION: The newly established unselected population-based pediatric NorDIBD cohort shows an increase in both incidence and extensiveness of newly diagnosed pediatric IBD over the last 4 decades and provides a foundation for future research into the long-term outcomes of pediatric IBD.