Inhaled short acting β agonist use in COPD and the risk of acute myocardial infarction
- 1Division of Clinical Epidemiology, Royal Victoria Hospital, McGill University Health Centre, and Departments of Epidemiology and Biostatistics and of Medicine, McGill University, Montreal, Canada
- 2Division of Respiratory Medicine, McGill University Health Centre
- Correspondence to:
Dr S Suissa, Division of Clinical Epidemiology, Royal Victoria Hospital, 687 Pine Avenue West, Ross 4.29, Montreal, Québec H3A 1A1, Canada;
- Accepted 21 September 2002
- Revised 21 August 2002
Background: A recent study found that short acting β agonists used in the treatment of asthma and chronic obstructive pulmonary disease (COPD) may increase the risk of acute myocardial infarction. We investigated this hypothesis in patients with COPD already at high risk of cardiac disease.
Methods: The Saskatchewan Health Services databases were used to form a population based cohort of all patients newly diagnosed with COPD over the age of 55 years identified between 1980 and 1997. All subjects were followed up until 1999, death, or the first occurrence of acute myocardial infarction. Those with a first acute myocardial infarction, fatal or non-fatal, were matched on calendar time and age with cohort members.
Results: The cohort consisted of 12 090 subjects including 1127 cases with fatal or non-fatal acute myocardial infarction. The adjusted rate ratio for current use of inhaled β agonists was 1.12 (95% confidence interval (CI) 0.95 to 1.33), and for first time use it was 1.02 (95% CI 0.52 to 2.00). There was also no significant increase in risk when the analysis was restricted to subjects with cardiac risk factors such as hypertension and diabetes, or to subjects not having been prescribed β blocker medications.
Conclusion: Short acting inhaled β agonist use among patients with COPD does not appear to increase the risk of fatal or non-fatal acute myocardial infarction.
This study was funded by grants from the Canadian Institutes for Health Research (CIHR), AstraZeneca, Boehringer-Ingelheim, and GlaxoSmithKline. Dr Suissa is the recipient of a Distinguished Scientist award from CIHR. Dr Assimes received a studentship award from the FRSQ during the study period. The McGill Pharmacoepidemiology Research Unit is funded by an infrastructure grant from the Fonds de la recherche en santé du Québec (FRSQ).