The importance of β2-agonists in myocardial infarction: findings from the Eastern Danish Heart Registry

PURPOSE: β2-Agonists are widely used for relief of respiratory symptoms. Studies so far have reported conflicting results regarding use of β2-agonists and risk of myocardial infarction (MI). Yet, coronary angiographical data and longitudinal outcomes data are sparse and could help explain if there is an association between use of β2-agonists and MI.

METHODS: Using a novel data-linkage of the Eastern Danish Heart Registry and nationwide administrative registries we identified a cohort of patients referred for acute coronary angiography due to ST-elevation MI (STEMI). Clinical and angiographical findings were compared between β2-agonist users and non-users.

RESULTS: Among 66,234 patients undergoing coronary angiography, 9857 patients had STEMI. Of these, 933 (9%) patients used β2-agonists. β2-Agonist users were more often without significant coronary stenosis (15% in β2-agonist users vs 9% in non-users; p<0.0001), odds ratio (OR) 1.68 (95% confidence interval (CI) 1.37-2.07; p<0.0001). The association was correlated to the number of filled prescriptions. One prescription: OR=1.00 (CI 95% 0.66-1.50; p=1.00)), 2-5 prescriptions: OR= 2.02 (CI 95% 1.47-2.78; p<0.0001), more than five prescriptions: OR=2.30 (CI 95% 1.69-3.12; p<0.0001). All-cause mortality during up to 14 years of follow-up was significantly higher among the β2-agonist-user group compared to the non-user group (34% vs 23%; p<0.0001), hazard ratio 1.36, 95% CI 1.18-1.56; p<0.0001).

CONCLUSION: Among patients referred to urgent coronary angiography for STEMI, use of β2-agonists was associated with a lower frequency of significant coronary stenosis and a higher mortality compared with non-users.