Incidence and Prevalence of Paediatric Inflammatory Bowel Disease Continues to Increase in the South of England

Objective: The incidence of paediatric inflammatory bowel disease (IBD) has been increasing over 25 years; however, contemporary trends are not established and the impact of COVID-19 on case rates is unclear.

Methods: Data from Southampton Children's hospital prospective IBD database were retrieved for 2002-2021. Incidence rates were calculated based on referral area populations and temporal trends analysed. Disease prevalence for those aged <18 years was calculated for 2017-2021. Monoclonal prescriptions were reported.

Results: In total, 1150 patients were included (mean age at diagnosis 12.63 years, 40.5% female). An estimated 704 patients had Crohn's disease (61.2%), 385 had ulcerative colitis (33.5%), and 61 had IBD unclassified (5.3%). Overall IBD incidence increased, β = 0.843, P = 3 × 10 -6 , driven by Crohn's disease, β = 0.732, P = 0.00024 and ulcerative colitis, β = 0.816, P = 0.000011. There was no change in IBDU incidence, β = 0.230, P = 0.33. From 2002-2021, 51 patients were diagnosed <6 years of age, 160 patients aged 6 to <10 years and 939 patients aged 10 to <18 years of age. Increased incidence was observed in patients aged 10 to <18 years of age (β = 0.888, P = 1.8 × 10 -7 ). There was no significant change in incidence of IBD in <6 years (β = 0.124, P = 0.57), or 6 to <10 years (β = 0.146, P = 0.54). IBD prevalence increased by an average of 1.71%/year from 2017 to 2021, β = 0.979, P = 0.004. The number of new monoclonal prescriptions increased from 6 in 2007 to 111 in 2021.

Conclusions: IBD incidence continues to increase in Southern England. Compounding prevalence and increased monoclonal usage has implications for service provision.