OBJECTIVES: Asthma is a chronic respiratory disease associated with relevant direct and indirect costs, which may be higher in patients with more severe forms of the disease. In this study, we aimed to estimate the nationwide indirect costs of asthma due to work absenteeism. In addition, we aimed to compare the indirect costs in patients with and without difficult-to-treat asthma.

METHODS: In the context of a population-based epidemiological study (EPI-ASTHMA), we identified a representative sample of Portuguese patients with a physician-confirmed diagnosis of asthma. Included patients were assessed for the frequency of workdays lost in the previous 12 months. We used the human capital method to quantify indirect costs associated with losses of work productivity. We applied a two-stage stratified cluster sampling design to obtain nationwide estimates. Results were presented separately for patients with and without difficult-to-treat asthma.

RESULTS: We estimated that, in Portugal, there are 254,064 employed people with asthma. We estimated that asthma is associated with an annual loss of 172,697 working days (average of 0.7 days per patient), corresponding to 19.1 million Euro in indirect costs (average of 75 Euro per patient). For employed patients with difficult-to-treat asthma (N=38,532), we estimated annual lost workdays of 67,552 (average of 1.7 days per patient), corresponding to 7.4 million Euro in indirect costs (193 Euro per patient). This compares with 105,145 days lost in patients without difficult-to-treat asthma (0.5 days per patient), corresponding to 11.7 million Euro (54 Euro per patient).

CONCLUSIONS: These results suggest that asthma has a significant impact on work productivity and that a better management of difficult-to-treat asthma can contribute to reduce indirect costs.