Aspirin remains common for primary prevention of CVD in the United States

Survey data shows that tens of millions of American adults continue to take a daily aspirin tablet in the hope of preventing cardiovascular disease, despite studies casting doubt on the drug's use and explicit recommendations to avoid it.

Although usage has decreased over the past few years, as of 2021, 18.5% of adults aged 40 and older (25.6 million people) reported taking aspirin for primary prevention, and the number is even higher (29.7%) among those aged 60 and older (18.5 million people).

Mohak Gupta, MD, of the Cleveland Clinic in Ohio, and colleagues reported their findings in a research paper published online Monday. Annals of Internal Medicine.

Gupta told TCTMD that, based on his clinical experience, he wasn't surprised that so many patients were taking aspirin, but he was a bit surprised by the scale of use, given that a clinical trial published in 2018 showed aspirin's limited effectiveness in modern preventive therapy.

These randomized trials include arrival In patients at intermediate CVD risk: Asprey In elderly patients, rise In diabetic patients, 2019 Guidelines The American College of Cardiology and the American Heart Association have announced that they no longer recommend the use of aspirin for primary prevention in adults aged 70 and older.

“All of this [in this study] “It's not recommended,” Gupta said, “and I believe there is some reasonable use of this that is medically justified. But I do believe there is certainly a portion of patients who don't need to take an aspirin every day for prevention. That's the message we're trying to get across.”

Nationally representative sample

To examine the impact of the trial and new recommendations on aspirin use, Gupta and his colleagues turned to the adult sample component of the National Health Interview Survey, a cross-sectional survey of a representative sample of U.S. adults.The analysis was limited to people aged 40 years or older who answered questions about aspirin use between 2012 and 2021 and included 160,414 people without CVD and 26,011 people with CVD, who together represent approximately 150 million Americans each year.

Of note, the study period ended one year before the U.S. Preventive Services Task Force. Finalized the latest recommendations Regarding the use of low-dose aspirin for primary prevention, the report advises against initiating aspirin for this purpose in adults aged 60 years or older and recommends individualized decisions for individuals aged 40 to 59 years with a 10-year CVD risk of 10% or greater.

During the study period, the prevalence of physician-advised aspirin use among those without CVD was lowest in those aged 40–59 years (9.7%), rising to 27.1% in those aged 60–69 years and 38.2% in those aged 70 years or older. Primary prevention use also tended to be higher in patients with a range of CVD risk factors, including obesity (22.7%), hypertension (33.9%), diabetes (42.1%), and hyperlipidemia (34.2%).

Certainly there are some patients who do not need to take a daily aspirin for preventive purposes. Mohak Gupta

Aspirin use for primary prevention remained relatively constant from 2012 to 2017 but began to decline thereafter. For all age groups combined, the proportion of people free of CVD decreased from 20.6% in 2012 to 14.4% in 2021, with an even larger decrease among older patients.

Additionally, self-use of aspirin for primary prevention among patients aged 70 years or older has decreased since 2018. The proportion of patients whose physicians recommended that they stop taking aspirin for primary prevention also increased over time.

For secondary prevention, aspirin use continued to decline slightly over time but has not changed significantly since 2018.

The researchers acknowledged that their study is limited by a lack of information to estimate CVD or bleeding risk, which would influence the decision to start or stop aspirin, and by its reliance on self-reported aspirin use history and CVD.

Still, at least some of the aspirin use observed in the study may be unnecessary, and patients and their doctors should have this discussion, Gupta said. “When taking any medication, it's essentially a balancing of risks and benefits,” Gupta said, adding that the decision to use aspirin should take into account a patient's age, bleeding and CVD risk, and preferences. Some patients may be willing to accept a slightly higher bleeding risk for the chance to prevent or delay a myocardial infarction or stroke, but others may not, he noted.

“I would encourage them to discuss this with their doctor, and that discussion is what we're emphasizing,” Gupta said, adding that this is especially important because the survey showed that about 5% of older adults take aspirin without a doctor's supervision.

“I think we're moving in the right direction. Usage is decreasing,” he said. But Gupta stressed that “we need to continue to work on this issue. When things are done on a large scale, both the benefits and the risks increase. So what we've shown here is that this use is happening on a large scale, and I think we need to look further into how harmful this is and reduce the harmful parts.”