Antiplatelet therapy and atherosclerotic cardiovascular disease risk
Early trials of aspirin in primary prevention were done when statins and blood pressure–lowering drugs were less widely used, so the incremental benefit of aspirin is likely to be smaller in people who have already had their ASCVD risk reduced by these drugs.
Previous recommendations to use antiplatelet therapy for primary prevention in people with diabetes were based on the assumption that these people had equivalent ASCVD risk to people with established ASCVD but without diabetes. A large randomised controlled trial investigated the harm–benefit profile of aspirin for the primary prevention of ASCVD in patients with diabetes. Although aspirin did reduce major cardiovascular events, the benefit was offset by an increased risk of major bleeding, supporting the recommendation that aspirin should not be used routinely in this population1.
ASCVD risk increases with age, but the risk of adverse effects from antiplatelet drugs is also higher in older people. In a large randomised controlled trial of patients 70 years and older who did not have ASCVD, aspirin increased the risk of major bleeding and did not reduce the risk of ASCVD2.
All patients with established ASCVD should receive an antiplatelet drug for the secondary prevention of cardiovascular events.