Background: The definitions of childhood asthma differ among epidemiological studies. We aimed to compare the diagnostic accuracy and agreement of previous asthma definitions and to evaluate questionnaire-driven asthma definition patterns.
Methods: Data on 808 participants aged 7-12 years from 20 schools were analyzed. Asthma definitions based on symptoms assessed by questionnaire, parent-reported medical asthma diagnosis, current use of asthma medication, airway reversibility after bronchodilatation, and increased (≥35 ppb) levels of exhaled nitric oxide (eNO) were compared with a gold standard (medical diagnosis of asthma with asthma symptoms in the past 12 months and/or airway reversibility). Concordance was assessed by Cohen's kappa. Data-driven analysis was applied to the questionnaire, and six scores were determined "asthma," "rhinitis," "cough," "non-specific respiratory symptoms," "treated asthma," and "uncontrolled asthma." Tree decisions were built using these scores.
Results: Definitions of asthma based on respiratory symptoms, airway reversibility, and parent-reported medical diagnosis had a low sensitivity but high specificity. Agreement between reported and objective measures was poor. Parent-reported medical asthma diagnosis, but not reversibility or eNO, was able to predict questionnaire-driven symptom patterns. Decision trees indicated that those with recent non-specific respiratory symptoms had a higher probability of positive bronchodilation.
Conclusion: A standardized operational definition of asthma should include a composite score based on reported asthma medical diagnosis, symptoms, and lung function.
Keywords: asthma; cough; rhinitis.
© 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.