Cost of asthma in Portuguese adults: A population-based, cost-of-illness study.

INTRODUCTION Asthma is one of the most frequent chronic diseases, putting a considerable economic burden on societies and individuals. We aimed to estimate the total cost of adult asthma in Portugal, as well as the extent to which direct and indirect costs are influenced by the level of asthma control. METHODS A nationwide, prevalence-based, cost-of-illness study using a bottom-up approach to calculate direct and indirect costs of asthma was conducted, using participant data from the Portuguese National Asthma Survey (INAsma). Direct (healthcare service usage, diagnostic tests and treatment) and indirect (absenteeism and transportation) costs were measured. Decision analytic modelling was used to perform multivariate deterministic sensitivity analysis. RESULTS On average, each adult costs 708.16€ (95%CI: 594.62-839.30) a year, with direct costs representing 93% (658.46€; 95%CI: 548.99-791.29) and indirect costs representing 7% (49.70€; 95%CI: 32.08-71.56). This amounts to a grand total of 386,197,211.25€ (95%CI: 324,279,674.31-457,716,500.18), with direct costs being 359,093,559.82€ (95%CI: 299,391,930.03-431,533,081.07). Asthma direct costs are 2.04% of the total Portuguese healthcare expense in 2010. The major cost domains were acute care usage (30.7%) and treatment (37.4%). Asthma control was significantly associated with higher costs throughout several domains, most notably in acute medical care. CONCLUSIONS Asthma in adults poses a significant economic burden on the Portuguese healthcare system, accounting for over 2% of the total healthcare expenditure in Portugal in 2010. It is important to note that a considerable portion of this burden might be eased by improving asthma control in patients, as uncontrolled patients' costs are more than double those of controlled asthma patients.