Perianal Crohn's Disease is More Common in Children and is Associated with Complicated Disease Course Despite Higher Utilization of Biologics: A Population-based Study from the epiIIRN

Both perianal and pediatric-onset Crohn's disease (CD) disease are associated with complicated disease course and higher drug utilization. We aimed to explore the differences between pediatric and adult-onset perianal CD and their disease course. We included all patients with newly diagnosed CD from 2005 to 2019 at two Israeli Health Maintenance Organizations, covering 78% of the population. A combination of ICD-9 codes, radiology and procedures was used to define fistulizing PCD and its severity according to the association with simple and complex perianal disease. A total of 12,905 patients were included (2,186 [17%] pediatric-onset, 10,719 [83%] adults), with a median follow-up of 7.8 years. PCD was diagnosed in 1,530 (12%) patients, with higher incidence in children (308 [14%] children vs. 1,222 adults [11%]; p