Incidence, clinical characteristics, and natural history of pediatric IBD in Wisconsin: A population-based epidemiological study

Background: Epidemiological studies of pediatric inflammatory bowel diseases (IBD) are needed to generate etiological hypotheses and inform public policy; yet, rigorous population-based studies of the incidence and natural history of Crohn's disease (CD) and ulcerative colitis (UC) in the United States are limited. Methods: We developed a field-tested prospective system for identifying all new cases of IBD among Wisconsin children over an 8-year period (2000-2007). Subsequently, at the end of the study period, we retrospectively reconfirmed each case and characterized the clinical course of this incident cohort. Results: The annual incidence of IBD among Wisconsin children was 9.5 per 100,000 (6.6 per 100,000 for CD and 2.4 per 100,000 for UC). Approximately 19% of incident cases occurred in the first decade of life. Over the 8-year study period, the incidence of both CD and UC remained relatively stable. Additionally, (1) childhood IBD affected all racial groups equally, (2) over a follow-up of 4 years, 17% of patients with CD and 13% of patients with patients with UC required surgery, and (3) 85% and 40% of children with CD were treated with immunosuppressives and biologics, respectively, compared with 62% and 30% of patients with UC. Conclusions: As in other North American populations, these data confirm a high incidence of pediatric-onset IBD. Importantly, in this Midwestern U. S. population, the incidence of CD and UC seems to be relatively stable over the last decade. The proportions of children requiring surgery and undergoing treatment with immunosuppressive and biological medications underscore the burden of these conditions.