Abstract
BACKGROUND: The effect of respiratory medications on risk of asthma death in the UK was studied using the General Practice Research Database. METHODS: A total of 96 258 individuals with a diagnosis of asthma were identified, 43 of whom had died as a result of their asthma. For each case 20 controls were selected. Relative risk (RR) estimates and 95% confidence intervals (CI) were computed for each respiratory drug category controlling for effects of age, sex, body mass index, smoking, frequency of visits to the GP, hospital admissions for asthma, and visits to a specialist. RESULTS: The strongest associations were found for at least 13 prescriptions of short acting beta agonists during the previous year (RR=51.6, 95% CI 7.9 to 345) and 7-12 prescriptions of short acting beta agonists (RR=16.2, 95% CI 2.6 to 101). Short acting beta agonists and inhaled steroids tended to be prescribed most frequently to the same patients. In patients who received more than one prescription per month of short acting beta agonists during the previous year, regular use of inhaled steroids was associated with a 60% reduced risk of asthma death (RR=0.4, 95% CI 0.2 to 1.0). CONCLUSIONS: Regular use of inhaled steroids is associated with a decreased risk of asthma death, and excessive use of short acting beta agonists is associated with a markedly increased risk of asthma death.