USPSTF: Risks of Daily Aspirin Use Outweigh Benefits

On October 12, the U.S. Preventive Services Task Force (USPSTF) issued draft recommendations that reconsider whether it is safe for most older adults to take daily low-dose aspirin to prevent heart attacks and strokes.

According to the Centers for Disease Control and Prevention (CDC), heart disease, stroke, and other cardiovascular diseases cause a third of all deaths in the United States each year—that’s more than 868,000 people.

One of the long-standing preventive steps that doctors have advised for older adults is taking a low dose of a blood-thinning medication called aspirin every day.

While aspirin can reduce the risk of strokes and heart attacks by preventing clots from forming in the blood vessels, it can also increase the risk of bleeding in the stomach, brain, and intestines—an outcome that can be fatal. The increased risk for bleeding also increases as people get older. 

Based on newer research, the Task Force is now proposing that:

• People age 60 and older who have not had a heart attack or stroke and do not have stents should not start taking aspirin.
• People ages 40 to 59 who do not have a history of cardiovascular disease, but who are at increased risk of cardiovascular events (for example because they have diabetes or obesity) should discuss the potential risks and benefits of taking a daily aspirin with their doctor before starting the medication.

Proposing New Guidelines

While it’s long-standing, the recommendation for most older adults to take daily low-dose aspirin as prevention has not gone unquestioned. In recent years, aspirin’s potential value in cardiovascular disease prevention has been de-emphasized, while lifestyle changes that patients can make to improve their heart health and circulation have been given greater emphasis.

The American Heart Association (AHA) and American College of Cardiology (ACC) jointly issued guidelines on the primary prevention of cardiovascular disease in 2019. The guidelines stated that aspirin “should be used infrequently in the routine primary prevention of [atherosclerotic cardiovascular disease] because of lack of net benefit.”

The Task Force’s new draft guidelines are an update to the previous recommendations, which were issued in 2016. Those guidelines advised doctors to consider prescribing daily low-dose aspirin as prevention for patients ages 50 to 69 who did not have a history of cardiovascular disease, based on their risk of having a cardiovascular event.

The risks of daily aspirin use, particularly bleeding risk, have also been brought up before. New research that has been published since 2016 suggests that the risk of bleeding in the brain and intestines associated with aspirin use far outweighs the drug’s potential benefits for many people.

Task Force member John Wong, MD, chief of the Division of Clinical Decision Making and a primary care clinician at Tufts Medical Center in Boston, says that “daily aspirin use may help prevent heart attacks and strokes in some people, but it can also cause potentially serious harms, such as internal bleeding.”

Should You Keep Taking Aspirin?

The new recommendations that are being proposed by the Task Force do not apply to people who are currently taking daily low-dose aspirin because they have already had a heart attack or stroke.

Chien-Wen Tseng, MD, MPH, a member of the Task Force and the associate research director in the department of family medicine and community health at the University of Hawaii John A. Burns School of Medicine, tells Verywell that people who are already taking low-dose daily aspirin “should continue to do so unless told otherwise by their clinician.”

Gathering Feedback

While the Task Force's recommendations are not binding, Tseng says that the group’s guidelines “often become U.S. health policy.” For example, recent guidelines have covered screenings for lung cancer and vitamin D deficiency.

The new Task Force guidelines on aspirin use are considered to be draft recommendations for the time being because the public—both experts and consumers—can make comments until November 8th.

After the period for comments closes, Tseng says that the Task Force members “take weeks to a few months to read and consider all of the comments” and “take each comment very seriously.”

Once the comments have been reviewed, Tseng says that the Task Force “can incorporate the ones we think will be helpful for the final version, such as how best to communicate the information to the public.”

What Experts Say

After the Task Force released its draft guidelines, cardiovascular medicine experts weighed in on the proposed changes.

The American Heart Association’s volunteer president, Donald M. Lloyd-Jones, MD, ScM, responded by reiterating the stance of the American College of Cardiology/American Heart Association’s primary prevention recommendations from 2019.

In a statement on October 12, Lloyd-Jones said that “in most adults, the benefit of protection against heart attacks and strokes is offset by the potential risk of bleeding caused by aspirin.” However, he added that “aspirin should be limited to only those adults at the highest risk for cardiovascular disease who also have a very low risk of bleeding.”

Determining whether a patient is more likely to be at risk for bleeding while they’re taking aspirin is an important consideration for clinicians to bear in mind.

Erin Michos, MD, MHS, associate professor of medicine at the Johns Hopkins School of Medicine and the director of Women’s Cardiovascular Health at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease, as well as one of the authors of the ACA/AHA 2019 guidelines on prevention of cardiovascular disease, tells Verywell that the harm that aspirin can cause also underscores the need for physicians to ask about all over-the-counter (OTC) drugs and supplements that a patient takes.

For example, Michos says that before considering having you take aspirin daily to help prevent cardiovascular conditions, your doctor needs to know if you already are taking ibuprofen regularly to treat pain because “ibuprofen can increase the risk of bleeding.”

Evidence—and Guidance—Evolves

Michos understands that people may see the updated guidance and be concerned that something that was previously recommended is now being discouraged, but she says that “evidence accrues over time” and as a result, guidelines can evolve and change.

While the new guidelines from the Task Force are being released now, Tseng says the committee started reviewing data back in 2018 when studies had found aspirin’s risks to be higher than its benefits in some patients. Tseng says that the Task Force “took the time we needed to review the clinical trials and other data.”

Michos says that “other preventive measures [to help prevent a heart attack or stroke] have gotten better,” over the last few decades. For example, a decrease in smoking, more guidance on tighter blood pressure control, and treatment with statins have helped researchers and clinicians feel more confident about advising against daily aspirin use for some of their patients—for now, at least.

In his statement, Lloyd-Jones stressed that the choices that patients make—including their diets, physical activity level, and other lifestyle behaviors—play a key role in the primary prevention of cardiovascular disease.

“More than 80% of all cardiovascular events may be prevented by making lifestyle changes,” said Lloyd-Jones. “The science continues to show that healthy lifestyle habits and effectively managing blood pressure and cholesterol, including with medications if needed, are the top ways to prevent a first heart attack or stroke—as opposed to taking aspirin daily.”

Is Taking Aspirin Ever Worth It?

Aspirin’s potential to prevent heart attacks and strokes is not what’s being challenged by the Task Force; rather, it’s the risk of bleeding that comes with daily use. That’s why research is ongoing to determine which patients could safely take aspirin and reap the benefits.

Jeffrey Berger, MD, director of the Center for the Prevention of Cardiovascular Disease at NYU Langone Health in New York City, tells Verywell that “as a prevention-focused cardiologist, I am surprised that in the 21st century we still don’t know who should receive aspirin for the prevention of a first heart attack or stroke.”

Berger compares aspirin to other commonly prescribed medications, like blood pressure medication and statins. “In most circumstances, we measure cholesterol to determine who should be on a statin. Similarly, we measure blood pressure to determine who should be on a blood pressure-lowering drug.”

When to suggest daily aspirin is less clear, and doctors also need to take a patient’s bleeding risk into account. That’s where Berger hopes to help. He’s studying platelets, the tiny blood cells that form clots and help the body stop bleeding. People who bleed easily do not have high enough levels of platelet activity.

“My research program is investigating how to measure platelet activity to help determine who should be on aspirin,” says Berger. “Stay tuned.”