Denise Herzog, Nicolas Fournier, Patrick Buehr, Vanessa Rueger, Rebekka Koller, Klaas Heyland, Andreas Nydegger, Christian P. Braegger

Intestinal complications in inflammatory bowel disease indicate active inflammation and typically result in the intensification of therapy. To analyse whether the rates of intestinal complications were associated with age at disease onset. Data from 1506 individuals with Crohn's disease (CD) and 1201 individuals with ulcerative colitis (UC) were obtained from the Swiss inflammatory bowel disease cohort study database, classified into groups on the basis of age at diagnosis (<10, <17, <40 and >40 years of age), and retrospectively analysed. In CD patients, the rates of stricturing (29.1-36.2%), abdominal penetrating disease (11.9-18.2%), resectional surgery (17.9-29.8%) and perianal disease (14.7-34.0%) were correlated with disease duration, but not age at diagnosis. However, paediatric-onset CD was associated with higher rates of multiple, rectal and anal strictures and earlier colon surgery. In addition, perianal disease occurred earlier, required earlier surgical intervention, and was more often combined with stricturing and penetrating disease. Finally, anal fissures were more prevalent among younger patients. In UC patients, the rates of progression or extension of disease (0-25.8%) and colectomy (3.0-8.7%) were dependent on disease duration, but not age at disease onset. Paediatric-onset disease was associated with a higher rate of extensive colitis at diagnosis and earlier progression or extension of disease, and nonsurgically treated patients with the youngest ages at onset more frequently required antitumour necrosis factor-α treatments. The higher rates of intestinal complications, including those of the small and large bowel and in the anal region, in paediatric-onset CD patients point towards a level of inflammation that is more difficult to control. Similar findings were also evident in UC patients.