Three-year outcomes of childhood inflammatory bowel disease in New Zealand: A population-based cohort study.

Background And Aim: High rates of inflammatory bowel disease (IBD) have been documented in New Zealand (NZ) children. The objectives of this study were to describe the outcomes and disease course of childhood IBD in the first 3 years following diagnosis.

Methods: All children diagnosed with IBD in 2015 in NZ were included. Clinical data obtained during routine care for 3 years following diagnosis were analyzed. Growth parameters, disease activity scores, and blood parameters were compared at diagnosis and follow up.

Results: Three-year outcome data were available for 48 of 51 children. At follow up, median age was 15.1 years, and 34 had Crohn's disease (CD), 11 had ulcerative colitis (UC), and three had IBD-unclassified (IBDU). Although disease progression including development of perianal disease occurred in 13 (38%) of 34 children with CD, the majority ( = 30) had inflammatory disease at follow up. Disease extension occurred in 25% (2/8) of children initially diagnosed with UC. Of all IBD patients, the mean body mass index z-score increased from -0.40 to +0.10 ( = 0.01). Disease activity scores reduced from diagnosis to follow up in both CD (mean pediatric Crohn's disease activity index 35-6, < 0.001) and UC (mean pediatric ulcerative colitis activity index 44-6, < 0.001). Overall, 56% of children received steroids, 44% of children with CD received biologic therapy, and four children with CD or UC had intestinal surgery.

Conclusions: Most children with IBD were in remission with improved growth 3 years after diagnosis. Biologic therapies were commonly prescribed. This is the first NZ study assessing disease course in pediatric IBD. Ongoing follow up will continue to inform outcomes.