Aspirin for Primary Prevention of CVD Remains Common in US

Tens of millions of US adults are sticking with their daily aspirin tablet in the hopes of preventing cardiovascular disease despite multiple studies questioning the practice as well as recommendations that explicitly discourage it, survey data suggest.

Although use has declined over the past several years, as recently as 2021, 18.5% of adults 40 and older—representing 25.6 million people—said they were taking aspirin for primary prevention, with that figure even higher (29.7%) among those 60 or older (representing 18.5 million people).

Mohak Gupta, MD (Cleveland Clinic, OH), and colleagues report their survey results in a research letter published online Monday in Annals of Internal Medicine.

Gupta told TCTMD he was not surprised, based on his clinical experience, to see that many patients were taking aspirin but was somewhat taken aback by the scale of its use considering the trials released in 2018 demonstrating aspirin’s limited benefit in the context of modern preventive therapies.

Those randomized trials included ARRIVE in patients at moderate risk for CVD, ASPREE in older patients, and ASCEND in those with diabetes, all of which informed the 2019 guidelines from the American College of Cardiology and the American Heart Association that discouraged use of aspirin for primary prevention in adults older than 70.

“I don’t think we’re saying that all of this use [in this study] is not recommended,” Gupta said. “Some of this, I believe, is a reasonable use, a medically justifiable use. But I do believe that there is definitely a proportion of these patients who do not need to be on a daily preventive aspirin. And that’s the message we’re trying to get out there.”

A Nationally Representative Sample

To look at the impact of the trials and the new recommendations in use of aspirin, Gupta and his colleagues turned to the National Health Interview Survey sample adult component, a cross-sectional survey of representative sample of US adults. This analysis was confined to those 40 and older who answered questions about aspirin use between 2012 and 2021 and included 160,414 individuals without CVD and 26,011 with CVD; together, they represented about 150 million Americans each year.

Of note, the study period ended a year before the US Preventive Services Task Force finalized its latest recommendations on use of low-dose aspirin for primary prevention, advising against initiating aspirin for this purpose in adults 60 and older and recommending an individualized decision for those ages 40 to 59 who have a 10% or greater 10-year CVD risk.

During the study period, the prevalence of aspirin use supported by medical advice among individuals without CVD was lowest in those ages 40 to 59 (9.7%), rising to 27.1% in those ages 60 to 69 and 38.2% in those 70 and older. Primary-prevention use also tended to be higher in patients with various CVD risk factors, including obesity (22.7%), hypertension (33.9%), diabetes (42.1%), and hyperlipidemia (34.2%).

There is definitely a proportion of these patients who do not need to be on a daily preventive aspirin. Mohak Gupta

Use of aspirin for primary prevention remained relatively consistent from 2012 to 2017 before starting to slide. With all age groups together, the rate declined from 20.6% in 2012 to 14.4% in 2021 for those without CVD, with greater drops among the older patients.

Moreover, self-use of aspirin for primary prevention declined after 2018 among patients 70 and older. There also was an increase over time in the proportion of patients who were advised by a physician to stop taking aspirin for primary prevention.

For secondary prevention, there was a small continuous decline in aspirin use over time, but without a major change after 2018.

The investigators acknowledge that the study was limited by the lack of information to estimate CVD or bleeding risks, which play into the decision to start or stop aspirin, and by its reliance on self-reported history of aspirin use and CVD.

Nonetheless, Gupta said, it’s likely that at least some of the aspirin use observed in the study is not necessary, and patients and physicians should be discussing this. “Taking any medication is essentially a balancing act between risks and benefits,” Gupta said, adding that the decision to use aspirin should take into consideration a patient’s age, bleeding and CVD risks, and preference. Some patients may be willing to take on a somewhat higher risk of bleeding for the chance to prevent or delay an MI or stroke, whereas others may not, he noted.

“I would encourage them to discuss this with their physicians. . . . Having that discussion is what we’re stressing,” Gupta said. That’s especially important, he added, because this study showed that about 5% of older adults were taking aspirin without being advised to do so by a physician.

“I think we are moving in the right direction; the use is coming down,” he said. But, Gupta stressed, “we need to continue to work on this. Whenever things are happening at scale, the benefits and risks both are amplified, and so I think what we’ve shown here is that this use is happening at scale, and we need to further explore how much of this may be harmful and cut down on the harmful part.”