P207 Colonic location at diagnosis of pediatric-onset Crohn’s disease is associated with a pejorative disease course: a two decades population-based study

International audience; Background Crohn's disease (CD) location would influence the risk of complications and therapeutic strategies. The objective of this study was to compare the clinical presentation at diagnosis and the natural history of colonic CD in comparison to ileal CD and ulcerative colitis (UC) in pediatric-onset inflammatory bowel disease. Methods All children (< 17 years) with a diagnosis of CD or UC made between 1988 and 2011 in a population-based registry were followed retrospectively until 2013. Presentation at diagnosis, risks of complicated disease, surgery, hospitalization and exposure to treatments in ileal CD (L1), colonic CD (L2) and UC were compared. Disease location was defined at diagnosis. In case of extension of the disease (L1 or L2 to L3), follow-up was censored. Results A total of 215 L1 patients, 234 L2 patients and 337 UC patients were included. At diagnosis, the proportion of males (L1 53.5%; L2 53.4%; UC 42.7%; p=0.012), age at diagnosis (15.0; 13.7; 14.0 years; p=0.003), family history of IBD (12.6%; 12.7%; 5.0%; p=0.005), diagnostic delay (3.0; 3.0; 2.0 months; p=0.001) and smoking prevalence (11.6%; 8.1%; 5.6%; p=0.041) were different between the three groups. Bloody stool and diarrhea at diagnosis was observed in respectively 14.9%, 44.4%, and 91.1% (p < 0.001) and 47.0%, 71.8%, and 65.0% (p < 0.001) of L1, L2 and UC. At diagnosis, granuloma was identified in 12.6% of L1 patients and 31.2% of L2 patients (p