For most older adults without heart disease the answer is no.
The medical world agrees that a small daily dose of aspirin can help people with heart disease lower their risk of heart attacks and strokes. But what if you don’t have heart disease? Should you take aspirin as preventive medicine? Research suggests perhaps not.
Studies show that for people without heart disease, a higher risk of bleeding may outweigh the benefits of taking aspirin daily. In fact, guidelines from the American College of Cardiology and the American Heart Association recommend against this practice.
"The general recommendation now is that if you have heart disease, then you should probably be on aspirin therapy," says Dr. Christopher Cannon, a senior physician in the cardiovascular division at Harvard-affiliated Brigham and Women’s Hospital. "If not, then you need to look at your potential risk for heart disease over the next 10 years and discuss it with your doctor."
Who’s taking it?
This advice sounds simple enough. However, many people take aspirin who don’t need it, and they often do so without their doctor’s knowledge.
A 2019 survey of 14,000 people ages 40 and older in the Annals of Internal Medicine found that about a quarter of those who did not have heart disease took daily aspirin. Of these, about 23% did so without a physician’s okay. Even more concerning, nearly half of survey participants ages 70 and older without heart disease took daily aspirin.
"While some people can benefit from aspirin therapy, for others, it may be unwise and potentially dangerous," says Dr. Cannon. "You should never begin taking regular aspirin just because you heard it’s good. It always should involve a decision-making process with your doctor."
Your doctor will prescribe aspirin therapy based on your specific needs and your risk for heart attacks, strokes, and bleeding. In general, prescriptions range from a low dose (81 mg) to a full dose (325 mg). Studies have found the benefit is generally similar at both levels. However, the lower amount has been linked with a lower risk of bleeding and therefore is usually the recommended dose.
So, where does aspirin therapy fit in your heart health plan? Here’s a breakdown of when you need aspirin therapy, when it may help, and when it’s best to avoid it.
The aspirin and clotting connection
Aspirin helps prevent heart attacks and strokes by interfering with how blood clots. When you have a cut that bleeds, cells called platelets gather at the wound site. The platelets help form a plug that seals the opening in the blood vessel, which stops the bleeding.
However, there are times when this process causes unwanted clotting. Fatty deposits (plaque) that form in arteries feeding the heart and brain can slow blood flow enough to allow small clots to form. Also, some of these plaques, even smaller ones, can suddenly break open. The broken plaque releases substances that attract blood platelets and can rapidly trigger a clot, block blood flow, and cause a heart attack or stroke.
Aspirin makes platelets less sticky, which keeps them from clumping together to form clots. That is the upside. The downside to less clotting is a higher risk of bleeding, especially in the gastrointestinal tract. Another effect of aspirin is that it weakens the stomach’s protective lining against stomach acid, making the stomach and intestines more vulnerable to ulcers, which can bleed. Signs of gastrointestinal bleeding include black stools, vomiting with specks that look life coffee grounds, and weakness.
Yes, aspirin helps
The people who most benefit from aspirin therapy are those who have been diagnosed with heart disease or who have suffered a heart attack or stroke caused by a blood clot (ischemic stroke). In these people, daily aspirin lowers the odds of a future attack. Aspirin therapy also helps prevent blood clots in the heart arteries for people who have had stent placement or coronary bypass surgery.
Maybe (ask your doctor)
In general, people ages 40 to 70 with diabetes who have a high risk of heart disease should consider aspirin therapy, says Dr. Cannon. High risk means you have at least a 10% chance of having a heart attack or stroke over the next 10 years. (To estimate your 10-year risk, use the calculator created by the American Heart Association and American College of Cardiology, at /heartrisk.)
People with diabetes and a lower risk for heart disease — less than 10% over 10 years — should discuss their options with their doctor. "Sometimes, the risk of a heart attack and bleeding are about the same, in which case you have to decide with your doctor which risk you want to avoid—a heart attack or bleeding," says Dr. Cannon.
Aspirin therapy may also be appropriate for people deemed to be at high heart risk based on visual evidence of plaque in their arteries. That evidence can come from an imaging test, such as a coronary artery calcium scan, a CT scan, or an ultrasound of the neck arteries. "Here, the benefit of aspirin often outweighs the risk, but whether a person may need aspirin depends on the individual situation," says Dr. Cannon.
There are some gray areas. For instance, some people without heart disease and at low risk for a heart attack or stroke may have already been taking daily aspirin for decades with no bleeding problems. Should they now stop? Others may have a low 10-year risk but slightly high cholesterol or high blood pressure. "In these cases, you need to consult your doctor to discuss individual risks and benefits," says Dr. Cannon.
Best to avoid
In general, people over age 70 without cardiovascular disease should avoid aspirin as a way to prevent a heart attack or stroke. A study in the Oct. 18, 2018, issue of The New England Journal of Medicine highlighted the higher risk of major bleeding when taking daily aspirin without significant health benefit. "Even if you have taken aspirin for a long time as primary prevention of heart disease, you should consider stopping once you reach age 70. But again, check with your doctor," says Dr. Cannon.
Most people at high risk for bleeding should probably avoid aspirin therapy. That includes those with a history of gastrointestinal bleeding, stomach ulcers, low blood platelets, blood clotting disorders, and people who take nonsteroidal anti-inflammatory drugs for arthritis or other inflammatory conditions.
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