Patients whose symptoms of inflammatory bowel disease (IBD) first appeared during their childhood usually experience more severe disease compared with those whose symptoms started later in adulthood, a study has found.

The study, titled “Paediatric onset inflammatory bowel disease is a distinct and aggressive phenotype — a comparative population‐based study,” was published in GastroHep.

IBD comprises a group of autoimmune disorders that cause inflammation and disrupt the function of the gastrointestinal (GI) tract. The disease may manifest during childhood (pediatric-onset IBD or pIBD) or later in life during adulthood (adult-onset IBD or aIBD).

Although previous studies have suggested that the symptoms of pIBD are more severe than aIBD, most of these studies were not performed at a population level and may, therefore, be subject to significant bias.

In this study, investigators from the University of Copenhagen in Denmark carried out a population-based study to evaluate if pIBD was indeed more aggressive than aIBD.

The Danish comparative cohort study involved a total of 333 pIBD patients who received their diagnosis before the age of 15, and 449 aIBD patients who were diagnosed after the age of 18.

Participants’ medical records were retrieved from the treating hospital and manually reviewed at the last follow-up visit. All clinical data was recorded and compared between both groups.

Results showed that pIBD patients tended to have lesions spread across more regions in their GI tract, compared to aIBD patients.

This was true for patients with pediatric-onset Crohn’s disease (pCD) — who had L4 disease localization (upper GI tract with or without bowel involvement) more frequently (24%) than those with adult-onset CD (aCD, 9%) — and for patients with pediatric ulcerative colitis (pUC), who had E3 disease localization (extensive disease) more frequently (67%) than those with adult-onset UC (aUC, 24%).

In addition, a higher percentage of pIBD patients (34%) progressed to a stage of complicated disease within seven years after being diagnosed, compared to aIBD patients (16%).

Investigators also found that pIBD patients tended to be treated with biologic agents and to require bowel resection (a surgical procedure in which a part of the bowel is removed) during follow-up more often than aIBD patients: 35% pIBD versus 11% aIBD patients received biologics within five years after diagnosis, and 29% pIBD versus 18% aIBD underwent bowel resection during follow-up.

Finally, both pCD and pUC patients were twice more likely to experience a relapse within the first seven years after being diagnosed compared to adult-onset patients.