Who Needs Aspirin?

Age, Family History, and Other Risk Factors Determine if Daily Aspirin Can Help Prevent a Heart Attack or Stroke

For many of us, aspirin was the go-to medicine of our youth. Everything from headaches, colds, and general aches and pains were treated with two aspirin and a glass of water.
For decades, aspirin was widely believed to be a safe way to protect healthy adults from heart attacks and strokes. But over the past couple years, new research has questioned this premise and many doctors have already stopped prescribing aspirin for adults at low risk of cardiovascular disease.
But because aspirin is so readily available, and because people may not be up on the latest research, there's a large group of people who may still be taking it, unnecessarily.
Harvard researchers reported in the July 23, 2019, issue of Annals of Internal Medicine that nearly 24% of adults ages 40 years or older without cardiovascular disease who don't need daily aspirin still take it for the prevention of heart disease. And almost half of adults 70 and older with no history of heart disease or stroke reported taking aspirin daily.
"Aspirin therapy is not for everyone, yet many people take it without their doctor's knowledge," says Dr. Randall Zusman, director of the Division of Hypertension at Harvard-affiliated Massachusetts General Hospital. "This can expose them to potentially dangerous side effects and can cause more harm than good."
Aspirin helps prevent the formation of blood clots in arteries that can restrict blood flow and lead to a heart attack or stroke. Aspirin may be prescribed by itself or in combination with a prescription anti-clotting medication like clopidogrel (Plavix).
The downside is that aspirin increases the risk of internal bleeding. This can range from a minor issue like noticeable bruising to more severe problems, such as gastrointestinal bleeding caused by irritation of the stomach lining, and rarely, bleeding in the brain. The recommended advice is that low-dose daily aspirin -- often 81 milligrams (mg) per day -- can protect people with heart disease who have had a heart attack or stroke from having another one.
Other candidates for aspirin therapy include people who've had a coronary artery bypass to reroute blood flow around blockages in the heart; people who've had a stent implanted to keep an artery open; and those with peripheral artery disease (significant plaque buildup in the leg arteries).
But what about everyone else? For instance, can daily aspirin prevent a first-time heart attack or stroke if you are at high risk for heart disease?
Probably not. A study in the Aug. 26, 2018, issue of The Lancet included more than 12,500 people, all of whom had several risk factors for heart disease, such as high cholesterol, high blood pressure, or smoking. They took either a daily 100-mg aspirin or a placebo. Over five years, the aspirin users did not have a lower risk of heart attacks or strokes compared with the placebo group. One exception is people with diabetes, a disease that raises the risk of heart disease. Research has found that low dose aspirin daily may protect these people from first-time heart attacks and strokes.
The biggest issue with aspirin therapy is identifying which otherwise healthy people might take low dose daily aspirin because they could benefit from a lower chance of heart attack or stroke with minimal risk. This is where it gets tricky.
New guidelines from the American Heart Association and American College of Cardiology advise against daily aspirin for prevention in otherwise healthy people without existing heart disease or stroke, in particular those older than 70. The guidelines point out that existing evidence suggests the risks for dangerous bleeding outweigh any potential heart benefits.
However, this does not mean that healthy people may never benefit from aspirin therapy, says Dr. Zusman.
"Some doctors might advise aspirin for people who have multiple risk factors that put them at especially high risk of heart attack or stroke, such as a strong family history of heart disease and high cholesterol, or plaque buildup in their arteries detected from a coronary calcium scan," he says. "Also, people over 70 may still benefit from aspirin therapy, but it depends on their risk of bleeding versus their cardiac risk profile."
A better approach for these people is to focus more on following a heart-healthy diet, exercising, and managing weight, adds Dr. Zusman. "For a majority of people, these can maximize the preventive benefits against a heart attack or stroke better than taking a daily aspirin."
The bottom line is that the decision to take low-dose aspirin is complicated and depends on the person. "Talk with your doctor, and never take a daily aspirin on your own," says Dr. Zusman.