Health care costs increase in patients with more severe asthma, but the effect of asthma exacerbations on costs among patients with more severe asthma has not been quantified.

This study compared direct health care costs between patients with moderate/severe persistent asthma with and without exacerbations.

Patients who had an asthma diagnosis (International Classification of Diseases–ninth revision–Clinical Modification code 493.x), were 12 to 64 years old, and were receiving controller therapy were identified from a large administrative claims database. Patients were categorized as having moderate/severe persistent asthma and were further evaluated for exacerbations during a 12-month exacerbation identification period. Patients with 1 or more exacerbations (asthma-related inpatient or emergency department visit or corticosteroid prescription) were matched to patients without exacerbations on demographic characteristics and asthma severity. Total and asthma-related health care costs during the 1-year study period after the exacerbation index date were calculated.

Patients with exacerbations had significantly higher total health care costs ($9223 vs $5011, P < .0001) and asthma-related costs ($1740 vs $847, P < .0001). The cost differences remained significant after controlling for patient differences by using multivariate models. Patients with exacerbations (n = 3830) had higher rates of sinusitis, allergy-related diagnoses or medications, pneumonia, and mental disorders and higher average Charlson Comorbidity Index scores at baseline. Patients with exacerbations filled their prescriptions for controllers more often and had higher asthma-related drug costs.

Patients with moderate/severe persistent asthma who had exacerbations had higher total and asthma-related health care costs than those without exacerbations. Moreover, controller medication use was higher in patients with exacerbations.