Aspirin
Loren Bonner
For years, millions of Americans have been taking low-dose aspirin daily to reduce their chances of heart attack and stroke. But now, as the evidence becomes even more conclusive, experts are doing an about-face. In April, the U.S. Preventive Services Task Force (USPSTF) updated its 2016 guidelines and no longer recommends routine use of aspirin for primary CVD prevention.
The new USPSTF guidelines recommend against initiating aspirin in adults 60 years and older due to the lack of information on the risk/benefit of aspirin for CVD prevention. However, the approach is acceptable for adults 40 years to 59 years old who have ≥ 10% risk for cardiovascular disease even though the payoff is low, according to USPSTF.
“Rather than a ‘one-size-fits-all’ approach, as has often been used with aspirin in the past, the updated recommendations are important because they reflect that the decision to use aspirin in younger patients [age 40–59 years] should be individualized on the basis of their estimated CVD risk and after shared decision making,” said Michael Ernst, PharmD, FCCP, BCGP, BCPS, a clinical professor in the department of pharmacy practice and science at the University of Iowa College of Pharmacy.
Overall, he said, health care providers have a much more comprehensive and integrated approach to managing CVD risk than they did in past decades. “I think the updated guideline reflects our new understanding that the value of aspirin for CVD prevention is much more nuanced than originally believed.”
Alignment with major trial results
The updated USPSTF guideline is both significant and timely, said Ernst. It incorporates evidence from several recent aspirin primary prevention randomized trials, which have become available since the last USPSTF update in 2016.
“A lot has changed in the contemporary trends in CVD risks and in risk factor management since some of the earlier trials of aspirin were conducted and which had previously served as the foundation for past guidelines,” Ernst said.
Aspirin for CVD prevention now has a more limited role based on the results of 3 major studies published in 2018—ASPREE (the Aspirin in Reducing Events in the Elderly), ASCEND (A Study of Cardiovascular Events in Diabetes), and ARRIVE (A Study to Assess the Efficacy and Safety of Enteric-Coated Acetylsalicylic Acid in Patients at Moderate Risk of Cardiovascular Disease). Each trial demonstrated an elevated risk of bleeding with aspirin use for adults without known CVD.
The harms were determined to outweigh the benefits, particularly among patients aged 70 years and older.
In response, the American College of Cardiology (ACC) and American Heart Association (AHA) released guidelines in 2019 explicitly recommending that low-dose aspirin for primary prevention of CVD be reserved for select high-risk patients and not given routinely as a preventive measure to adults older than 70 years.
USPSTF’s new guidance sets the bar lower, at age 60 years. The risk is particularly high, the organizations all agree, for older adults with a history of bleeding or those taking anticoagulants, steroids, or anti-inflammatories.
“Although the specific age categories differ, overall, the USPSTF guideline aligns similarly with the ACC/AHA guideline, particularly in the notion that the decision to use aspirin for CVD prevention should be individualized,” said Ernst, who was coauthor of the ASPREE papers.
The USPSTF guideline recommends that for adults 40 years to 59 years old, providers should first estimate CVD risk using a CVD risk estimator, and if the risk is 10% or greater, they should use shared decision-making, taking into account potential benefits and harms.
The ACC/AHA recommendation stated that low-dose aspirin might be considered in select adults ages 40 to 70 years at higher CVD risk but not at increased risk of bleeding.
“In both sets of guidelines, I think there is now an appreciation that the risks of bleeding may offset or reduce the net potential benefits of aspirin, particularly for those individuals at low CVD risk, anyone at high risk of bleeding, and as a person ages—presumably due to the increased risk of bleeding that accompanies age,” Ernst said.
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Clinician summary: Aspirin use to prevent cardiovascular disease
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What does the
USPSTF recommend?
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For adults aged 40 years to 59 years with an estimated 10% or greater 10-year CVD risk: The decision to intiate low-dose aspirin use for the primary prevention of CVD in this group should be an individual one.
Grade C: The USPSTF recommends selectively offering or providing this service to individual patients based on professional judgment and patient preferences. There is at least moderate certainty that the net benefit is small.
For adults 60 years or older: Do not initiate aspirin for the primary prevention of CVD.
Grade D: The USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.
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To whom does this
recommendation
apply?
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This recommendation applies to adults 50 years or older without signs or symptoms of CVD or known CVD and who are not at increased risk for bleeding (e.g., no history of gastrointestinal ulcers, recent bleeding, or other medical conditions, or taking medications that increase bleeding risk).
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What’s new?
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The USPSTF has changed the age ranges and grades of its recommendation on aspirin use.
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The USPSTF currently recommends considering initiating aspirin in persons with an estimated 10% or greater CVD risk at a younger age: 40 years instead of 50 years.
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Aspirin should be initiated selectively based on individual decision making rather than routinely for all persons in the recommended age and CVD risk group.
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There is a new recommendation not to initiate aspirin in adults 60 years or older for primary prevention.
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The evidence is unclear whether aspirin use reduces the risk of colorectal cancer or incidence of mortality.
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How to implement
this recommendation?
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Consider the patient’s age.
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For adults aged 40 years to 59 years: Estimate CVD risk using a CVD risk estimator.
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In patients whose estimated CVD risk is 10% or greater, use shared decision-making, taking into account potential benefits and harms of aspirin use, as well as patients’ values and preferences, to inform the decision about initiating aspirin.
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For patients initiating aspirin use, it would be reasonable to use a dose of 81 mg/day.
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For adults 60 years or older: Do not initiate aspirin for primary prevention of CVD.
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Why is this
recommendation and topic important?
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CVD is the leading cause of mortality in the U.S., accounting for more than one in four deaths. Each year, an estimated 60,500 Americans have a first heart attack and about 610,000 experience a first stroke.
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What are additional
tools and resources?
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The Million Hearts initiative provides information on improving cardiovascular health and preventing heart attack and stroke at millionhearts.hhs.gov
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CDC has resources related to risk of heart disease and the prevention of heart disease for patients and health professionals at www.cdc.gov/heartdisease/index.htm
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The National Heart, Lung, and Blood Institute has patient resources related to coronary heart disease at www.nhlbi.nih.gov/health-topics/coronary-heart-disease
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Where to read the
full recommendation statement?
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Visit the USPSTF website (www.uspreventiveservicestaskforce.org/uspstf) or the JAMA website (jamanetwork.com/journals/jama/fullarticle/2791399) to read the full recommendation statement. This includes more details on the rationale of recommendation, including benefits and harms; supporting evidence; and recommendation of others.
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Note: The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decision making to the specific patient or situation. Adapted from: USPSTF. Aspirin use to prevent cardiovascular disease. JAMA. 2022;327(16)1577–1584.
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Re-education
Pharmacists, like all health care providers, will be challenged in educating the public that aspirin does have significant risks associated with it, even at the low “baby dose.” This comes after decades of being told it was beneficial.
“Aspirin has been around for many, many years and almost everyone has some personal experience with it. It has been successfully marketed as a simple and cheap preventative for your heart health. And because it’s universally available without prescription, and used at a ‘baby dose,’ unfortunately this reinforces the belief that it is without risk,” said Ernst.
When updating medication histories, Ernst said it’s a good idea to ask patients about aspirin use along with other OTCs they are taking.
“For those patients purchasing aspirin, ask if they are doing so upon recommendation from their doctor or by their personal choice, as this may create opportunities for more dialogue,” said Ernst. “Never assume that their doctor also knows they are taking aspirin—facilitating that conversation between patient and doctor about the need for aspirin is important.”
And although much of the attention with the new guideline is on the more limited role of aspirin, there are patients who may benefit from aspirin who are not taking it. In the same way pharmacists can screen for patients on aspirin who appear not to have increased CVD risk, Ernst said they can also screen those not on aspirin but who may benefit according to the guideline.
“There are areas of uncertainty with aspirin that still remain—particularly whether to stop aspirin in older adults who have been on it for many years without problems,” said Ernst. “Post-hoc analyses of the trials used to inform the updated guideline may shed some light on this and whether there is increased risk of CVD and stroke in the short term after discontinuing aspirin, particularly in older adults.”
Aspirin has also been recommended for colon cancer prevention and remains an active area of research.
Translating evidence into practice
Just prior to the release of the guideline, estimates found that as many as one-third of adults may still be using aspirin for primary prevention and without apparent indication.
Ernst is hopeful this new guideline from USPSTF will help with the adoption of the evidence into clinical practice.
“The results of the recent trials informing the USPSTF update have been published now for a couple of years but translating evidence into actual practice is challenging because there will always be those who will say that the results of the study don’t apply to me or my patient,” Ernst said.
He also reminds pharmacists that guidelines are just guidelines—a roadmap that’s generally good to follow but will need to be individualized at times.
“The guideline draws attention to this nuance by recommending use of a CVD risk estimator to gauge how much CVD risk there is and help inform the discussion of risk/benefit balance,” Ernst said. “At the end of the day, there is no substitute for clinical reasoning [with] your individual patient.” ■