The impact of asthma medication guidelines on asthma controller use and on asthma exacerbation rates comparing 19971998 and 20042005

The relationship between asthma controller medication use and exacerbation rates over time is unclear at the population level. To estimate the change in asthma controller medication use between 2 time periods as measured by the controller-to-total asthma medication ratio and its association with changes in asthma exacerbation rates between 19971998 and 20042005. The study design was a cross-sectional population-level comparison between individuals from 19971998 and 20042005. Study participants were individuals aged 5 to 56 years identified as having asthma in the Medical Expenditure Panel Survey (MEPS). The main outcome measures were a controller-to-total asthma medication ratio greater than 0.5 and asthma exacerbation rates (dispensing of systemic corticosteroid or emergency department visit/hospitalization for asthma) in 19971998 compared with 20042005. The proportion of individuals with a controller-to-total asthma medication ratio greater than 0.5, when adjusted for other demographic factors, has improved by 16.1% (95% CI: 10.8%, 21.3%) for all individuals from 19971998 to 20042005. Annual asthma exacerbation rates did not change significantly in any group from 19971998 to 20042005 (0.27/year to 0.23/year). African American and Hispanic individuals with asthma had higher asthma exacerbation rates and a lower proportion with a controller-to-total asthma medication ratio greater than 0.5 than whites in both 19971998 and 20042005; however, these differences were not statistically significant. An increase in asthma controller-to-total medication ratio in a sample reflective of the US population was not associated with a decreased asthma exacerbation rate comparing 19971998 and 20042005.