International trends in admissions and drug sales for asthma

Abstract

Objective: To test whether national patterns of asthma drug use, particularly inhaled corticosteroids (ICS), are related to the rate of acute severe asthma exacerbations.

Design: The relation of international trends in hospital admissions for asthma with asthma drug sales was examined using country-specific regressions over the period 1990-1999. Pooled estimates of the regression coefficients were calculated using random effects models.

Results: Data on asthma admissions and asthma drug sales (including the sub-category ICS) were obtained from 11 countries. There was a negative relationship between falling admissions and rising sales of respiratory drugs and ICS in 9 of these 11 countries. A pooled estimate of the change in asthma admission rate per 10,000 associated with a unit increase in sales rate was -6.3 (95% CI -10.4 - -2.3) for all asthma drugs and -11.2 (95% CI -19.7 - -2.8) for ICS.

Conclusion: At the national level, there is good evidence that over the last decade, increased sales of asthma drugs, and ICS in particular, were associated with a decline in rates of hospital admission for asthma. This is consistent with a beneficial effect of increasing use of asthma drugs, but other explanations such as decreasing prevalence could also be responsible.