Aspirin Should Play Limited Role in Primary Prevention: Review

Recent clinical trials testing aspirin for the primary prevention of cardiovascular events should give physicians pause about its widespread use in the general population, particularly among adults 70 years and older, according to a new review published today in the Annals of Internal Medicine.

Michael Pignone, MD (University of Texas, Austin), and Darren DeWalt, MD (University of North Carolina, Chapel Hill, NC), state that “aspirin therapy should not be initiated for primary prevention” in this older population, although the decision about stopping treatment remains less clear. For the now 70-year-old patient who was started on aspirin earlier in life, Pignone and DeWalt suggest continuing with it unless bleeding risk unrelated to age has increased.     

“I do not believe the new evidence is sufficiently different to warrant stopping aspirin in those who are [at] sufficiently high cardiovascular risk to benefit from taking it and who do not have an increased risk of bleeding,” Pignone told TCTMD. “This new evidence does present an opportunity to review aspirin use and to make sure the benefit-to-harm ratio remains favorable. Such a review is probably a good idea periodically for all chronic medications.”

That new evidence eroding support for widespread aspirin use comes from several trials, among them ASPREE, ASCEND, and ARRIVE. In ASPREE, which included 19,114 individuals 70 years or older, 100 mg of enteric-coated aspirin failed to reduce the risk of cardiovascular events compared with placebo but was associated with a 38% higher risk of major bleeding and a 14% increased risk of all-cause mortality. 

The ASCEND trial evaluated the role of aspirin in patients with diabetes but without cardiovascular disease and showed that while treatment reduced the risk of vascular events, the risk of bleeding was just too high to justify aspirin’s use. The ARRIVE trial showed no benefit of aspirin in primary prevention when used in adults at moderate risk for cardiovascular events.

Pignone estimated that anywhere from 20% to 30% of US adults aged 40 years and older take aspirin for primary prevention even though the overall magnitude of benefit is likely small. In 2016, the US Preventive Services Task Force sharpened their recommendations on aspirin use for primary prevention, stating it should only be used in adults 50 to 59 years old who have a 10-year risk of cardiovascular disease greater than 10% and who were willing to take the drug for more than 10 years (B recommendation).

In their “Ideas and Opinion” article, Pignone and DeWalt contend that among middle-aged adults with or without diabetes, an individualized approach focusing on cardiovascular risk assessment should be the goal when deciding whether or not to recommend aspirin therapy. If the patient still has an elevated risk of cardiovascular disease—defined as more than 1% per year— after being counseled on lifestyle changes and treated with other preventive therapies, then aspirin can be offered, they state.

“Our assessment is that the totality of the evidence suggests that in high-risk individuals there is still a role for aspirin for primary prevention when other risk-reducing therapies, such as statins, smoking cessation, and blood-pressure treatment, have been utilized,” said Pignone.