The natural history of ulcerative colitis in a pediatric population: a follow-up population-based cohort study

Background: The natural history of ulcerative colitis (UC) has been poorly studied in children. Methods: We performed a retrospective study in children diagnosed with UC with a follow-up. The diagnosis of UC was based on clinical, radiologic, endoscopic, and histologic examinations. We estimated the occurrence of colectomy, proctitis, and extraintestinal manifestations (EIMs) at the onset of the diagnosis and at the end of the study period. Results: We identified 115 UC patients between 1986 and 2003 with a mean age at diagnosis of 10.6 +/- 5.1 years. The cumulative rate of colectomy was 4.1% at 1 year, and 16% at 10 years. EIMs were experienced by 20% of the children; 48% had arthritis, 35% had sclerosing cholangitis, and 17% had aphthous stomatitis. Proctitis was noted in 29 patients and it was not associated with an increased risk of colectomy ( relative risk = 1.4; 95% CI = 0.7-4.5), and girls were twice more likely to develop proctitis. The pathologic reading for disease extensions was recorded for all children at entry and only 62 children had pathological results at maximum follow-up. At entry, 25% of the children only had ulcerative proctitis (E1) localization, 40% had left-sided UC (E2), and 35% had extensive UC (E3). Among the patients with E1 localization, 20% had progressed to E2 and 80% had progressed to E3; among the patients with E2 localization, 40% had progressed to E3. Age, gender, and EIMs at time of diagnosis were not associated with extension of disease at maximal follow-up. The Z score of body mass index (BMI) of children was significantly higher at the end of the study. At diagnosis, 85% of patients received 5-aminosalicyclic acid, 60% received steroids, and 11% received an immunomodulator. The majority of patients were still using systemic steroids at and after 5 years from their entry date. Only 32 of the 91 children on steroids did not receive an immunomodulator. Conclusion: Pediatric UC is associated with high rates of EIMs and colectomy that are not dependent on age, gender, or race, but is associated with a high rate of proctitis among girls. Understanding the clinical course of UC can optimize therapeutic interventions.