Validity of asthma diagnoses and patterns of anti‐asthmatic drug use in a cohort of 2053 Danish children

BACKGROUND AND AIMS: When investigating and treating asthma in children, diagnosing must be precise and valid. There is a need for studies researching asthma in children showing how to use registry‐based, epidemiological data. We examined the feasibility and validity of using anti‐asthmatic drug prescription data to identify children with asthma and assessed medication patterns in children with and without confirmed asthma. METHODS: We used population‐based Danish prescription data and hospital discharge registries to identify all children aged 0 to 14 years who had redeemed at least one prescription for an inhaled anti‐asthmatic drug. Individual asthma cases were validated by hospital discharge information and by their treating general practitioners according to international asthma guidelines. RESULTS: In total, 2053 children, out of a population of 20181, had redeemed at least one prescription of any inhaled anti‐asthmatic drug. The positive predictive value (PPV) of having two different asthma medications prescribed in 1 year was 80.2% for presence of true asthma, with a sensitivity of 59%. Corresponding estimates of PPV/sensitivity of at least one prescription for an inhaled corticosteroid (ICS) were 79% and 58%, respectively, while the true asthma PPV with at least one LABA prescription increased to 97%. Among children with confirmed asthma, one‐third had not used Beta2‐agonist therapy as part of their treatment. Conversely, among children without confirmed asthma, 40% were prescribed a minimum of two prescriptions for any kind of inhaled anti‐asthmatic drug, and 12% and 9% used an ICS or Leukotriene receptor antagonist, respectively. CONCLUSIONS: Anti‐asthmatic drug prescription data could be used to identify children with true asthma, with reasonable accuracy. The observed pattern of anti‐asthmatic medication usage among children with and without confirmed asthma suggests that there is room for therapeutic improvement.