Epidemiology of severe asthma in children: a systematic review and meta-analysis.

Background: Severe asthma significantly impacts a minority of children with asthma, leading to frequent symptoms, hospitalisations and potential long-term health consequences. However, accurate global data on severe asthma epidemiology is lacking. This study aims to address this gap, providing data on severe asthma epidemiology, regional differences and associated comorbidities.

Methods: We conducted a rigorous systematic review and meta-analysis following a registered protocol (PROSPERO CRD42023472845). We searched PubMed, Scopus and Web of Science for cohort or cross-sectional studies published since 2003, evaluating severe asthma incidence and prevalence in children. Study quality and risk of bias were assessed using STROBE guidelines.

Results: Nine studies investigating European children with asthma (aged 5-18 years) were included in the meta-analysis. No significant publication bias was found. The overall severe asthma prevalence in children with asthma was 3% (95% CI 1-6; I²=99.9%; p<0.001), with no significant difference between males and females. Prevalence estimates varied significantly depending on the diagnostic criteria used (Global Initiative for Asthma: 6%; European Respiratory Society/American Thoracic Society: 1%; other: 3%). Because none of the examined studies were prospectively designed, incidence rates could not be determined.

Conclusions: This systematic review and meta-analysis provide the first robust assessment of severe asthma prevalence among European children. Our findings underscore the need for comprehensive research to address knowledge gaps in severe asthma, including determining incidence rates, standardising definitions, investigating regional differences and evaluating comorbidities and treatment strategies.