Bronchodilator treatment and deaths from asthma: case-control study

Abstract Objective To investigate the association between bronchodilator treatment and death from asthma. Design Case-control study. Setting 33 health authorities or health boards in Great Britain. Participants 532 patients under age 65 who died from asthma and 532 controls with a hospital admission for asthma matched for period, age, and area. Main outcome measures Odds ratios for deaths from asthma associated with prescription of bronchodilators and other treatment, with sensitivity analyses adjusting for age at onset, previous hospital admissions, associated chronic obstructive lung disease, and number of other drug categories. Results After full adjustment, there were no significant associations with drugs prescribed in the 4-12 months before the index date. For prescriptions in the 1-5 years before, mortality was positively associated with inhaled short acting β2 agonists (odds ratio 2.05, 95% confidence interval 1.26 to 3.33) and inversely associated with antibiotics (0.59, 0.39 to 0.89). The former association seemed to be confined to those aged 45-64, and the association with antibiotics was more pronounced in those under 45. Significant age interactions across all periods suggested inverse associations with oral steroids confined to the under 45 age group. An inverse association with long acting β2 agonists and a positive association with methylxanthines in the 1-5 year period were non-significant. Conclusion There was no evidence of adverse effects on mortality with medium to long term use of inhaled long acting β2 agonist drugs. The association with short acting β2 agonists has several explanations, only one of which may be a direct adverse effect.