Chronic conditions associated with paediatric onset inflammatory bowel diseases: A population‐based study

OBJECTIVE: Several conditions are associated with inflammatory bowel disease (IBD), including immune-mediated inflammatory diseases (IMIDs), extraintestinal manifestations (EIMs), and psychiatric disorders. This study aimed to describe at population-level the comorbidities and their relative burden in paediatric-onset IBD (pIBD). METHODS: All patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) before age 17 between 1988 and 2011 and recorded in the EPIMAD population-based registry were retrospectively followed until 2013. Comorbidities included chronic diseases, obesity (defined as a body mass index [BMI] z-score >1.645), and underweight (defined as a BMI z-score <-2), conditions requiring hospitalisation, serious infections, pneumopathy, meningitis, pyelonephritis, IMID, and EIM. RESULTS: A total of 1344 patients were included (1007 CD, 337 UC), with a median age at diagnosis of 14.3 years (interquartile range 11.7-16.0). Over a median follow-up of 8.3 years (4.3-13.9), 15.8% developed at least one EIM, 9.3% at least one IMID, 12.7% developed dermatological conditions, and 5.1% serious infections; 18.4% were classified as underweight and 8.5% as obese. Younger age at diagnosis (<14 years) and more extensive disease were associated with an increased risk of EIM and underweight, while CD was independently associated with underweight (hazard ratio, 3.3; 95% confidence interval, 2.0-5.0). Patients with dermatological conditions or IMID were more frequently treated with biologic therapies. The incidence of obesity, IMID and dermatological conditions increased across the study period. CONCLUSIONS: In this population-based pIBD cohort, the most common conditions were underweight, IMID, dermatological diseases, EIM and obesity.