Use of low-dose acetylsalicylic acid for cardiovascular disease prevention: A practical, stepwise approach for pharmacists.

Low-dose acetylsalicylic acid (ASA) is recommended in patients with established cardiovascular disease. However, the role of ASA in those without cardiovascular disease (i.e., primary prevention) is less clear, which has led to discordance among Canadian guidelines. In 2018, 3 double-blind, randomized controlled trials were published that evaluated ASA 100 mg daily versus placebo in patients without established cardiovascular disease. In the ASPREE trial, ASA did not reduce the risk of all-cause death, dementia, or persistent physical disability in patients ≥70 years of age but increased the risk of major bleeding. In the ARRIVE trial, ASA failed to lower the risk of a composite of cardiovascular events but increased any gastrointestinal bleeding in patients at intermediate risk of cardiovascular disease. In the ASCEND trial, ASA significantly reduced the primary composite cardiovascular outcome in patients with diabetes for a number needed to treat of 91 over approximately 7.4 years. Yet major bleeding was increased with ASA for a number needed to harm of 112. Therefore, in most situations, ASA should not be recommended for primary cardiovascular prevention. However, there are additional indications for ASA beyond cardiovascular disease. Thus, a sequential algorithm was developed based on contemporary evidence to help pharmacists determine the suitability of ASA in their patients and play an active role in educating their patients about the potential benefits (or lack thereof) and risks of ASA.