What constitutes an obstructive ventilatory impairment in a pediatric population? A comparative study of five definitions by scholarly societies

To ascertain the frequency of obstructive ventilatory impairment (OVI) among children/adolescents referred for spirometry, using definitions provided by various international respiratory societies. This cross-sectional, bi-centric study included 602 children/adolescents aged 6 to 18 years. Subjects completed a medical questionnaire, and clinical and anthropometric data were collected. Spirometric measurements were performed using two spirometers. OVI was assessed using five definitions: i) 2023-Global Initiative for Asthma (GINA): FEV₁ < 80% and FEV₁/FVC ≤ 0.90; ii) Irish College of General Practitioners (ICGP): FEV₁/FVC < 0.70; iii) European Respiratory Society and American Thoracic Society (ERS-ATS): FEV₁/FVC z-score < −1.645; iv) National Institute for Health and Care Excellence (NICE): FEV₁/FVC < 0.70 or FEV₁/FVC z-score < −1.645; and v) Canadian Thoracic Society (CTS): FEV₁/FVC < 0.80 or a FEV₁/FVC z-score < −1.645. The frequency of OVI varied significantly (Chi-square test < 0.001) depending on the definition applied: ICGP (7.6%), ERS-ATS or NICE (19.3%), 2023-GINA (24.9%), and CTS (27.9%). This indicated that the definitions are not equivalent in identifying OVI. The rate of OVI in pediatric populations varies considerably based on the diagnostic criteria used. Clinicians and researchers should therefore interpret prevalence data cautiously and always specify which definition was applied.