Economic Burden of Asthma in Northwest Iran.

Background: The economic burden of asthma is a major public health concern. This study estimates the economic burden of asthma in Northwest of Iran. Methods: A longitudinal study was conducted between 2017 and 2018 in Tabriz (Iran) using the Persian version of the Work Productivity and Activity Impairment (WPAI) questionnaire. Direct and indirect costs associated with asthma were estimated based on the societal perspective, prevalence-based approach, and bottom-up method. Annual indirect costs were estimated using the human capital (HC) method. The structural equation model was used to evaluate the relationship between costs, sex, and asthma severity. Results: A total of 621 patients with asthma were enrolled in the study. Significant differences were found between female and male patients for the mean cost of radiology (P=0.006), laboratory (P=0.028), and diagnostic (P=0.017) tests at baseline, and for laboratory (P=0.012), and diagnostic (P=0.027) tests at one-year follow-up. The more severe asthma, the more significant the costs for annual physician office visits (P=0.040) and medications (P=0.013). As asthma severity increased, significantly higher expenditures were observed in women for days lost from work at baseline (P=0.009) and one-year follow-up (P=0.001), and in men for productivity loss at work due to impairment at baseline (P=0.045). A significant association between indirect costs and the cost of impairment-related lost productivity at work (ß=3.29, P<0.001), and between severe asthma and indirect costs (ß=32.36, P<0.001) was observed. Conclusion: High costs are incurred by Iranian asthma patients, especially because of impairment-related productivity loss at work associated with asthma exacerbation.