Incidence, Management, and Outcomes of Very Early Onset Inflammatory Bowel Diseases and Infantile-Onset Disease: An Epi-IIRN Study

Background & Aims: In this nationwide study from the Israeli Inflammatory Bowel Disease Research Nucleus, we aimed to describe the incidence of very early onset inflammatory bowel diseases (VEOIBDs) with a focus on infantile-onset disease and to compare management and disease course with older children. Methods: Data were retrieved from the 4 Israeli Health Maintenance Organizations covering 98% of the population. Pediatric-onset IBD was categorized as follows: adolescent onset (10 to <18 y), early onset (6 to <10 y), VEOIBD (0 to <6 y), toddler onset (2 to <6 y), and infantile onset (<2 y). Results: A total of 5243 children with 35,469 person-years of follow-up evaluation, were diagnosed with IBD during 2005 to 2020: 4444 (85%) with adolescent onset, 548 (10%) with early onset, and 251 (4.8%) with VEOIBD, of whom 81 (1.5%) had infantile onset. The incidence of pediatric-onset IBD increased from 10.8 per 100,000 in 2005 to 15.3 per 100,000 in 2019 (average annual percentage change, 2.8%; 95% CI, 2.2%–3.4%), but that of VEOIBD remained stable (average annual percentage change, 0%; 95% CI, -2.5% to 2.6%). The infantile-onset and toddler-onset groups were treated less often with biologics (36% and 35%, respectively) vs the early onset (57%) and adolescent-onset groups (53%; P <.001). The time to steroid dependency was shorter in infantile-onset (hazard ratio [HR], 2.1; 95% CI, 1.5–2.9) and toddler-onset disease (HR, 1.6; 95% CI, 1.2–2.0) vs early onset and adolescent-onset disease, but time to hospitalizations, time to surgery, and growth delay were worse only in infantile-onset disease. In a multivariable model, infantile-onset patients had a higher risk for surgery (HR, 1.4; 95% CI, 1.1–1.9) and hospitalization (HR, 1.7; 95% CI, 1.2–2.4) than the toddler-onset group. Conclusions: The incidence of VEOIBD remained stable. Infantile-onset IBD had worse outcomes than older children, while toddler onset had mostly similar outcomes, despite less frequent use of biologics.