Abstract
AIMS: To explore the factor structure of asthma severity and asthma control and to compare the results of different approaches to asthma severity classification on the distribution of costs of asthma medication. METHODS: Comparison of four different approaches to asthma severity classification and factor analysis of asthma control descriptors. A correlation analysis between costs and the different approaches to severity classification was performed. RESULTS: The factor analysis suggests that asthma control consists of at least two factors. Four approaches to severity classification were explored and all except the 'GINA EXPANDED' classification tended to place patients in the most severe category. The pharmaceutical costs varied between 0 and 75 SEK per day (0 and 5.31 GBP; 0 and 7.68 EURO). CONCLUSIONS: There is a considerable overlap between asthma control and asthma severity. None of the approaches used in this study present a superior satisfactory solution to the classification problem.