Aspirin in primary prevention: Can we individualize care?

Aspirin is very effective in preventing ischemic events in subjects with acute myocardial infarction, ischemic stroke or evidence of clinical cardiovascular disease, forming the basis of current evidence based guidelines (1-3). In this patient population, aspirin use results in a 10% relative reduction in vascular death and 20% relative reduction in any serious vascular event (absolute risk reduction of 1.5% in aspirin users). In fact, the number needed to treat to prevent a single death, myocardial infarction or stroke in subjects with established cardiovascular disease is lower for aspirin compared with other proven medications, such as statins or ACE-inhibitors (3). While aspirin therapy decreases incident cardiovascular events, it also increases risk of major bleeding and hemorrhagic stroke. For secondary prevention the magnitude of benefit outweighs the risk of major bleeding (4). In patients without clinical cardiovascular disease, however, the benefit to risk ratio for aspirin use in primary prevention of cardiovascular events is less clear.