Compounding prevalence: the continued rise in paediatric IBD – a worrying trend

Another recent study, presented at ECCO 2024 in Stockholm, provided the first prospective PIBD incidence data for the entire United Kingdom since 1999 [3]. This study, performed over an 18-month period in 2021–2022, captured all new PIBD diagnoses below 16 years of age across 34 PIBD centres. The accurate incidence cohort comprised 2324 patients [55% Crohn’s Disease (CD), 33% Ulcerative Colitis (UC) and 12% IBD unclassified] and point prevalence in February 2023 was 49.3/100,000. The overall UK PIBD incidence was 12.5/100,000, with an incidence rate ratio (IRR) of 2.4 compared to the 1999 data. The most significant increases were in the UC cohort (IRR 2.9) and there were notable differences across the four UK nations. The number of cases diagnosed under the age of six years remained low overall, at 5.6%, and age at diagnosis was stable at 12.2 years. Fifteen patients were diagnosed under the age of two years, with only five having an identified monogenic disorder (IPEX syndrome =1, STXP3 variant =1, XIAP deficiency =3). There was twice the expected rate of IBD in those with an Asian ethnicity (self-reported), with significant differences in IBD subtype across ethnicities (e.g. 64% of those with a black ethnic background had CD).

Granot et al. recently published data on the differences in adult-onset versus paediatric-onset IBD using a registry-based cohort in Israel [4]. They examined disease characteristics and treatment exposures in 3316 adult-onset and 853 paediatric-onset (≥6 and <18 years) IBD patients from their registry who had been diagnosed between 2000 and 2022. As previously described, paediatric patients presented with more extensive disease and received more intensified therapies (including biologicals and JAK inhibitors). Those with paediatric UC also had higher rates of E3 colitis (61% vs 39%), leading to greater exposure to systemic steroids (61% vs 42%), immunomodulators and biologicals. In the case of CD, children and young people had more L3 (ileocolonic) disease and perianal involvement compared to their adult-onset counterparts. Kaplan-Meier curve and Cox proportional hazards analyses showed significantly lower 15-year biologic-free survival from diagnosis among those with paediatric-onset IBD compared to those with adult-onset IBD (p<0.001), indicating greater and earlier use of biologics in the former.

The epidemiology of paediatric IBD continues to provide interesting clues and insights into aetiology and risk, with monogenic forms also leading to further research in genetics and immunology [5]. It is crucial to also consider the broader implications for healthcare systems, families and the patients themselves, with many countries still in the ‘acceleration or ‘compounding prevalence’ epidemiological stages of the disease [6]. As the number of paediatric cases continues to grow, we are facing significant challenges in ensuring timely diagnosis, effective treatment and comprehensive support for children and young people. The increase in incidence also serves to highlight the urgent need for more research into the underlying causes and, more importantly, potential preventive strategies. Moving forward, a focus on optimising care pathways, increasing awareness and investing in specialised resources will be key to addressing this growing public health concern.

References

1. Caron B, Honap S, Peyrin-Biroulet L. Epidemiology of inflammatory bowel disease across the ages in the era of advanced therapies. J Crohns Colitis 2024;30(Suppl 2):ii3–5.
2. Sarter H, Crétin T, Savoye G, et al. Incidence, prevalence and clinical presentation of inflammatory bowel diseases in Northern France: a 30-year population-based study. Lancet Reg Health Eur 2024;18;47:101097.
3. Henderson P, Dobson L, PINPOINT Collaborators, IBD Registry. PINPOINT: The epidemiology of paediatric-onset Inflammatory Bowel Disease in the United Kingdom – a prospective, national, cohort study. J Crohns Colitis 2024;18(Suppl 1):i163.
4. Granot M, Kopylov U, Loberman-Nachum N, et al. Differences in disease characteristics and treatment exposures between paediatric and adult-onset inflammatory bowel disease using a registry-based cohort. Aliment Pharmacol Ther 2024;60:1435–46.
5. Zheng HB, de la Morena MT, Suskind DL. The growing need to understand very early onset inflammatory bowel disease. Front Immunol 2021;26:12:675186.
6. Kaplan GG, Windsor JW. The four epidemiological stages in the global evolution of inflammatory bowel disease. Nat Rev Gastroenterol Hepatol 2021;18:56–66.