Differences in phenotype and disease course in adult and paediatric inflammatory bowel disease - a population-based study

Background Few studies have compared phenotype and disease course in children and adults with inflammatory bowel disease (IBD). Aim To compare phenotype, treatment and disease course in children (<15 years) and adults (>= 18 years) with IBD. Methods Two population-based cohorts comprising paediatric (2001-2006) and adult (2003-2004) patients from Copenhagen County and City were studied. Results Twenty children and 106 adults with ulcerative colitis (UC), and 29 children and 67 adults with Crohn's disease (CD) were included. Median follow-up time was 4.8 years (children) and 5.2 years (adults). Children with UC had more extensive disease compared to adult patients [14 (70%) vs. 20 (19%), P < 0.001]. The risks of starting systemic steroid treatment and AZA/MP were higher for paediatric UC patients compared to adult UC patients; hazard ratio (HR): 3.1 (95% CI: 1.8-5.3) and HR: 2.5 (1.3-5-9), respectively. Steroid dependency was more frequent in paediatric than in adult UC patients [9 (45%) vs. 9 (8%), P < 0.001]. Mild disease course was less frequent in children with UC compared to adult patients [7 (35%) vs. 76 (72%), P = 0.002]. Paediatric and adult CD patients did not differ regarding treatment or disease course. Cumulative 5-year surgery rates for paediatric and adult patients were 5% and 9% for UC (N.S.) and 18% and 21% for CD (N.S.), respectively. Conclusions Paediatric UC patients had more extensive disease, were more often treated with systemic steroids and AZA, had a higher frequency of steroid dependency and a more severe disease course compared to adult UC patients. No differences were found when comparing paediatric and adult CD patients.