Some seniors across the United States continue to take a daily aspirin in the hopes of reducing their cardiovascular disease risk, even though the practice is only recommended for certain high-risk patients — and taking it without a doctor’s recommendation can come with significant risks.

Cardiovascular diseases affect the heart and blood vessels and sometimes can lead to heart attacks or strokes. Most heart attacks and strokes occur when a blockage in the arteries, caused by plaque buildup, stops blood from traveling to the heart muscle or the brain — but here’s where aspirin comes in.

Aspirin helps thin the blood, which can prevent these blood clots from forming. That is why it had long been recommended to take a daily low-dose aspirin to reduce your risk. However, because aspirin thins the blood, it comes with the risk of excessive bleeding.

In recent years, the medical and scientific communities have realized that the risk of aspirin may outweigh the benefits for many patients, especially older adults and adults already taking statins or other medications.

The American College of Cardiology and the American Heart Association updated their guidelines in 2019 to say that “aspirin should be used infrequently in the routine primary prevention” of atherosclerotic cardiovascular disease because of lack of net benefit. Primary prevention refers to patients who have no history of cardiovascular disease, heart attack or stroke and are taking aspirin to prevent a first case.

The US Preventive Services Task Force’s final recommendations on aspirin use, issued in 2022, came after years of recommending aspirin to prevent heart attack and stroke.

The USPSTF — a group of independent experts that makes recommendations to help guide doctors’ decisions and their recommendations also influence insurance companies’ reimbursement decisions — now recommends against adults 60 or older starting to take a low-dose aspirin for the prevention of a first cardiovascular disease event. It’s recommended that adults ages 40 to 59 who have a 10% or greater risk of developing the disease in the next decade make individual decisions on whether to start taking a low-dose aspirin regularly.

Yet several doctors say that despite the risks, some of their patients continue to follow the outdated guidance and take a daily low-dose aspirin when it’s not recommended.

The latest research on the prevalence of aspirin use to prevent cardiovascular disease suggests that in 2021, nearly a third of adults 60 or older without cardiovascular disease were still using aspirin.

The study, published Monday in the Annals of Internal Medicine, includes data on more than 180,000 people from the US Centers for Disease Control and Prevention’s National Health Interview Survey. An analysis of the data found that about 19% of surveyed adults 40 or older reported taking aspirin for the primary prevention of the disease. Among adults 60 or older, nearly 30% reported taking aspirin to prevent cardiovascular disease, and around 5% of all adults 60 or older reported using aspirin without medical advice.

“I was somewhat surprised by the magnitude of ongoing aspirin use in older adults,” Dr. Mohak Gupta, resident physician at Cleveland Clinic and lead author of the study, said in an email.

The study suggests that millions of US adults who’ve never had cardiovascular disease could still be taking a daily aspirin, despite recommendations against it.

A separate survey conducted last year by researchers at the University of Michigan found that about 1 in 4 adults surveyed, ages 50 to 80, reported taking aspirin regularly, around three or more days in a typical week – and this was seen among more men than women.

Among those regularly taking aspirin, 89% reported taking a low-dose aspirin, according to the survey, while 11% indicated they take regular strength aspirin, which makes their risk of excessive bleeding even higher.

About half of older adults regularly taking aspirin reported starting more than five years ago; about 19% said they started four to five years ago, and 30% started within the past three years. The survey, called the National Poll on Healthy Aging, was administered online and via telephone in July and August 2023 and included more than 2,600 adults.

‘This is the nature of science’

Because aspirin historically has been seen as a preventive tool for cardiovascular disease, it has been difficult to change some of the societal views and behaviors among older adults.

“Aspirin has been recommended for preventing a first heart attack or stroke since the late 1990s,” Gupta said. “As a result, aspirin use for primary prevention of cardiovascular disease has remained highly prevalent, especially among older adults who are at higher risk of cardiovascular events.”

Early studies on aspirin use, dating back to the 1980s and 1990s, showed that there was benefit to taking aspirin for the primary prevention of cardiovascular disease, said cardiologist Dr. Donald Lloyd-Jones, a past president of the American Heart Association and chair of the department of preventive medicine at Northwestern University.

“But think back at what else was happening at those times. We didn’t really use statins in very many patients. We weren’t doing a good job controlling blood pressure. And so aspirin, as the final safety net for preventing a heart attack or stroke, because it prevents blood clot formation, aspirin had room and it had space to work,” Lloyd-Jones said.

As aspirin was studied more closely, and as more patients at risk of cardiovascular disease started to take statins to help control their cholesterol levels, it became clear that the risks of aspirin use outweighed the benefits for certain patients, Lloyd-Jones said.

He added, however, that there are still subgroups of people for which the benefits of aspirin continue to outweigh the risks, and the guidance for them should not be ignored either.

“This is the nature of science. We make these broad recommendations for populations, but as we study individuals, we find that there are actually still situations where the benefit of aspirin — that is, the likelihood that we’re going to prevent a heart attack or stroke — will outweigh the risk of aspirin, which is that we could cause major bleeding,” said Lloyd-Jones, who was not involved in the new study on aspirin use among US adults.

“It’s really important that we’re crystal clear and precise that people who’ve had a heart attack or a stroke or who have a stent should be taking aspirin,” he said. “I’ve had my own patients come back and say, ‘Oh yeah, I saw the news. I stopped my aspirin,’ and that’s dangerous.”

The American Heart Association’s current recommendation is that no one should take daily low-dose aspirin without talking to their doctor first, especially if they have an aspirin intolerance, are at risk of gastrointestinal bleeding or hemorrhagic stroke, drink alcohol regularly, are undergoing any simple medical or dental procedures, or are older than 70. For people who have had a heart attack or stroke, their health care providers may want them to take aspirin to help prevent another event.

Yet it remains unclear when someone already taking a daily low-dose aspirin for their cardiovascular health should stop — and that might be an individual decision between a patient and their doctor.

“While guidelines recommend against starting preventive aspirin in older adults, there is uncertainty about the optimal age to discontinue preventive aspirin in those already taking it, as these two scenarios have different risk-benefit considerations,” Gupta said.

‘Communication gap is the chief reason’

The new study in Annals of Internal Medicine underscores “an important and concerning trend,” that many older adults continue to take aspirin for their cardiovascular health despite the updated recommendations, Dr. Dave Montgomery, a cardiologist at Piedmont Healthcare in Atlanta, who was not involved in the new research, said in an email to CNN.

“It brings to light a gap in effective dissemination of these guidelines to the general public. The other alarming aspect is that many individuals are taking aspirin without the guidance of a healthcare provider,” Montgomery said.

“The communication gap is the chief reason for this. The guidelines are clear and based on good science. We just haven’t communicated this new guidance effectively or broadly enough,” he added. “The decision to use aspirin must be an individual one, based on the person’s unique risk profile. No two cases are exactly the same, and I strongly advise that no one should make a change in their prevention strategy without the counsel of a medical professional.”

Dr. Howard Weintraub, a preventive cardiologist at NYU Langone Health in New York, said that he has seen among his own patients that some older adults continue to regularly take aspirin to prevent cardiovascular disease despite the shift in guidance.

For those patients, Weintraub said that he can conduct tests to analyze their blood pressure, cholesterol levels and weigh a personalized risk-benefit profile for them in order to recommend whether they stop taking aspirin or continue to do so. For some patients, the risk of excessive bleeding that comes with taking aspirin regularly outweighs the benefits.

“The drug that they may feel to be very benign, may have some baggage or potential adverse events,” Weintraub said. But for others, aspirin may still be the right choice.

Regardless, any patient taking aspirin regularly should discuss that behavior with their physician, Weintraub said.

“They should disclose that they’re using it. They should have a conversation with their primary or cardiologist, whoever is in their mind trustworthy, and come to an understanding as to how they should go forward,” Weintraub said. “Adopting a more personalized, individualized course of therapy may have a great benefit.”

And to reduce the risk of cardiovascular disease, Weintraub recommended that people stop smoking if they smoke, lose weight, eat healthy foods, control their cholesterol levels and try to prevent high blood pressure.

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