Association between naproxen use and protection against acute myocardial infarction.

BACKGROUND The association between the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and acute myocardial infarction (AMI) is unclear. Nonsteroidal anti-inflammatory drugs vary in their antithrombotic properties, with naproxen having a particularly effective antithrombotic potential. OBJECTIVE To compare the effect of naproxen vs other NSAIDs in the prevention of AMI in an older population. METHODS Population-based, matched case-control study. Patients (aged > or =65 years) in Quebec had been hospitalized for AMI between January 1, 1992, and December 31, 1994. The admission date for AMI was considered the index date. Control subjects were randomly selected from a Quebec drug and physician claims database. For each case, a control was matched with the same index date, age (within 2 years), and sex. Cases and controls were required to have at least 1 year of pharmaceutical and medical records before the index date to identify risk factors for AMI and exposure to naproxen or other nonaspirin NSAIDs. Concurrent exposure to a medication was defined as exposure to that medication at the index date. Logistic regression analyses were used to evaluate the association between the use of naproxen and other NSAIDs in the prevention of AMI, adjusting for potential confounders. RESULTS Included in the study were 4163 cases and 14 160 controls. Determinants (adjusted odds ratios [95% confidence intervals]) of AMI included use in the prior year of anticoagulants (0.76 [0.64-0.90]), nitrates (2.01 [1.86-2.17]), antidiabetic agents (1.72 [1.56-1.90]), antihypertensive agents (1.36 [1.28-1.45]), and lipid-lowering agents (0.83 [0.75-0.91]), as well as concurrent exposure to naproxen vs other NSAIDs (0.79 [0.63-0.99]). CONCLUSION Compared with other NSAIDs, concurrent exposure to naproxen has a protective effect against AMI.