Natural history of pediatric Crohn's disease: a population-based cohort study.

Abstract

The natural history of pediatric Crohn's disease and risk factors necessitating surgery have not been thoroughly described. In a geographically derived incidence cohort diagnosed from 1988 to 2002, we identified 404 Crohn's disease patients (ages, 0-17 years at diagnosis) with a follow-up time >or=2 years. Median follow-up time was 84 months (range, 52-124 months). The most frequent disease location at diagnosis was the terminal ileum/colon (63%). Follow-up was characterized by disease extension in 31% of children. Complicated behavior was observed in 29% of children at diagnosis and 59% at follow-up. Kaplan-Meier survival estimates of the cumulative incidence of surgery were 20% at 3 years and 34% at 5 years from diagnosis. Multivariate Cox models showed that both structuring behavior at diagnosis (hazard ratio [HR], 2.54; 95% confidence interval [CI]: 1.58-4.01) and treatment with corticosteroids (HR, 2.98; 95% CI: 1.64-5.41) were associated with increased risk for surgery, whereas treatment with azathioprine (HR, 0.51; 95% CI: 0.33-0.78) was associated with decreased risk. Azathioprine was introduced earlier in the course of disease in patients not undergoing surgery than in patients requiring surgery. Pediatric Crohn's disease was characterized by frequent occurrence, with time, of a severe phenotype with extensive, complicated disease. Immunosuppressive therapy may improve the natural history of this disease and decrease the need for performing surgery.