Oral Corticosteroid Use and the Risk of Acute Myocardial Infarction in Chronic Obstructive Pulmonary Disease

Abstract

Given the limited efficacy of oral corticosteroids in treating chronic obstructive pulmonary disease (COPD), the possible cardiac side effects of oral corticosteroids are of particular concern in an elderly population. The impact of the use of oral corticosteroids on the risk of acute myocardial infarction (AMI) in a cohort of patients with COPD was studied. The Saskatchewan health services databases were used to form a population-based cohort of 5648 patients aged 55 years or older who received a first treatment for COPD between 1990 and 1997. A nested case-control analysis was conducted: 371 cases presenting with a first myocardial infarction were matched with 1864 controls according to the length of follow-up, the date of cohort entry and age. Conditional logistic regression was used to adjust for sex, severity of COPD, systemic hypertension, diabetes and prior cardiovascular disease. Only the current use of corticosteroids was associated with an increased risk of AMI (adjusted RR=2.01 [95% CI 1.13 to 3.58]), particularly when the current dose was larger than 25 mg/day of prednisone or the equivalent (adjusted RR=3.22 [95% CI 1.42 to 7.34]). This observed increase in risk rapidly returned to baseline after the cessation of the medication, suggesting that the use of such high doses reflected the treatment of acute exacerbations of the disease. An association was found between the current use of oral corticosteroids and the occurrence of an AMI, suggesting that acute exacerbations of COPD are associated with an increased risk of acute coronary syndromes.