Natural history of Crohn's disease: comparison between childhood- and adult-onset disease.

Background: Childhood-onset Crohn's disease (CD) might reflect a more severe form of disease. To test this hypothesis we analyzed the long-term natural history of CD in an adult cohort of patients with childhood-onset compared to adult-onset CD.

Methods: We selected 206 childhood-onset CD patients among 2992 adult patients with a diagnosis of CD established before December 31, 2000. Disease characteristics were prospectively assessed during follow-up until December 2007 and compared to adult-onset CD patients matched 2 to 1 on gender, year of CD diagnosis, and disease location.

Results: Compared to adult-onset CD, patients with childhood-onset CD were more likely to have a severe disease, with an increased year-by-year disease activity index (37% of patient-years in childhood-onset group versus 31% in the adult-onset group, P < 0.001). Immunosuppressant requirement was also increased with a 10-year cumulative risk of 54 +/- 3% in childhood-onset CD group versus 45 +/- 2%, in the adult-onset CD group (P < 0.001). Cumulative risks of stricturing and penetrating complications and surgical resections were not statistically different between groups. Accordingly, these events occurred at a younger age in the childhood-onset CD group. At the age of 30 years the actuarial risk of having undergone an extensive intestinal resection was 48 +/- 5% in the childhood-onset group versus 14 +/- 2% in the adult-onset group (P < 0.001).

Conclusions: Patients with childhood-onset CD exhibit a more active disease and require more immunosuppressive therapy. This feature is observed irrespective of the disease location, suggesting an intrinsic more severe phenotype.