Impact of inhaled corticosteroids on asthma hospitalization in Sweden

This paper has two purposes. The first is to examine whether increased medication of inhaled corticosteroids by asthmatic patients is correlated with an improvement in asthma control, measured as a reduction in asthma hospitalizations. The other purpose, if such a relationship can be established, is to analyse the economic consequences. Regional data on asthma hospitalization, i.e. number of bed-days, and sales of anti-asthmatic drugs from 14 regions in Sweden between 1978 and 1989 were used (covering 71% of the Swedish population). The data were analysed in multivariate pooled cross-section, time-series regressions. The variation in bed-days was explained by three variables: the sales of inhaled corticosteroids; total supply of in-patient care; and sales of inhaled bronchodilators, which were used as a proxy for asthma prevalence. The results indicate that sales of inhaled corticosteroids are significantly correlated with decreased hospitalizations for asthma. Assuming that the correlation also reflects a causal relationship, an increase in sales of inhaled corticosteroids by 1 defined daily dose (DDD) per day and 1000 inhabitants gave, on average over the study period, a reduction of 1.7 bed-days for asthma in in-patient care per 1000 inhabitants.