Long-term outcome of pediatric-onset Crohn's disease: A population-based cohort study.

BACKGROUND: Pediatric-onset Crohn's disease (CD) may represent a more severe form of disease. The aim of this study was to describe long-term outcome and identify associated risk factors of complicated behavior in a large population-based pediatric-onset CD cohort. PATIENTS AND METHODS: Cases included all patients recorded in the EPIMAD registry diagnosed with definite or probable CD between January 1988 and December 2004, under the age of 17 years at the time of diagnosis, with at least two years of follow-up. RESULTS: Five hundred and thirty-five patients were included. Median follow-up was 11.1 years [IQR, 7.3-15.0]. At the end of follow-up, 8% (n = 44) of patients had pure ileal disease (L1), 8% (n = 44) had pure colonic disease (L2), and 83% (n = 439) had ileocolonic disease (L3). L4 disease and perianal disease were observed in 42% (n = 227) and 16% (n = 85) of patients, respectively. At the end of follow-up, 58% (n = 308) of patients presented complicated disease behavior (B2, 39% and B3, 19%), and 42% (n = 163) of patients with inflammatory behavior at diagnosis had evolved to complicated behavior. During follow-up, 86% of patients (n = 466) received at least one course of corticosteroids, 67% (n = 357) of patients had been exposed to immunosuppressants and 35% (n = 187) of patients received at least one anti-TNF agent. Forty-three percent (n = 230) of patients underwent at least one intestinal resection. The overall mortality rate was 0.93% and the SMR was 1.6 [0.5-3.8] (p = 0.20). Five cancers were reported with a crude cancer incidence rate of 1.1% and an SIR of 3.3 [1.2-7.0] (p = 0.01). In a multivariate Cox model, ileal (HR, 1.87 [1.09-3.21], p = 0.022) or ileocolonic (HR, 1.54 [1.01-2.34], p = 0.042) and perianal lesions at diagnosis (HR, 1.81 [1.13- 2.89], p = 0.013) were significantly associated with complicated behavior. CONCLUSION: About 80% of patients with pediatric-onset CD presented extensive ileocolonic disease during follow-up. The majority of patients evolved to complicated behavior. Surgery, cancer and mortality were observed in 43%, 0.9% and 0.9% of patients, respectively.