The pattern of risk of myocardial infarction in patients taking asthma medication: a study with the General Practice Research Database.

AIM: To describe the patterns of risks of acute myocardial infarction (MI) during exposure to long-acting beta2-agonists (LABA). METHODS: The study population consisted of patients aged 18+ years prescribed LABA or short-acting beta2-agonists (SABA) in the UK General Practice Research Database (GPRD). The outcomes included acute MI as recorded in GPRD and hospitalization for acute MI as obtained from the national registry of hospital admissions in England. The patterns of the hazard rates over time (i.e. absolute risks) were evaluated. RESULTS: The study population included 507,966 patients, who received a total of 5.5 million inhaled SABA, 4.0 million inhaled corticosteroids (ICS) and 1.3 million LABA prescriptions. In patients who recently started asthma medication, there were substantial changes in the hazard rates of MI over time: hazard rates were increased shortly following the prescription and then decreased. The hazard rates of MI in GPRD and of MI hospitalizations were proportional over time between inhaled SABA, LABA and ICS. Heavy long-term users (13+ Rx of the same asthma drug in the 1 year before) had increased risks of MI both with inhaled SABA and ICS. The relative rate in the heavy long-term users was 1.6 with inhaled SABA, 1.1 with LABA and 1.7 with ICS. The pattern of risk was similar between LABA with and without concomitant ICS use. CONCLUSION: The patterns of risks of MI were broadly similar between inhaled SABA, LABA and ICS, suggesting that there were no major differences between these drugs.