The incidence and prevalence of paediatric inflammatory bowel disease in Scotland: A nationwide study from 2015 to 2018

OBJECTIVES: Scotland is known to have the highest incidence of paediatric-onset inflammatory bowel disease (PIBD) in the United Kingdom and one of the highest worldwide; however, data on prevalence is lacking. We aimed to calculate the PIBD incidence and prevalence rates in Scotland during 2015 to 2018. METHODS: Incident and prevalent cases of PIBD were prospectively recorded by the three Scottish regional paediatric gastroenterology networks covering all paediatric units nationwide. PIBD was defined as children <16 years of age with Crohn's disease, ulcerative colitis or inflammatory bowel disease type unclassified. The incidence rate for the period from 2015 to 2018, the point prevalence (30th June each year) and the period prevalence (calendar year) were each calculated using publicly accessible Scottish population data. RESULTS: In total, 438 patients were diagnosed with PIBD in Scotland over the 4-year study period, providing an overall incidence rate of 12.0/100,000 person-years. The number of prevalent patients per year ranged from 518 to 538, with the highest period prevalence 58.5/100,000 person-years (01 January 2016-31 December 2016) and the highest point prevalence 45.9/100,000 persons (30 June 17). One hundred and fifty-nine patients ≥16 years of age remained within paediatric services in 2017; differences in transition practices were observed across regions. CONCLUSIONS: The Scottish PIBD incidence and prevalence remain the highest reported in nationwide studies worldwide (aged < 16 years). The high prevalence is in keeping with the high incidence rate and minimal mortality rate, so continues to rise. The true caseload within paediatric services, including patients ≥16 years of age, may be up to 30% higher.