A daily dose of aspirin is often recommended for people with heart disease, especially for those at highest risk. (BIGSTOCK)

The toll that heart attacks and strokes take on Americans is staggering. About 715,000 people have heart attacks each year — 125,000 of them are fatal — while strokes affect more than 795,000 people, killing almost 130,000. ¶ Taking a low daily dose of aspirin, also known as aspirin therapy, can help prevent those conditions by blocking the formation of blood clots that can clog the arteries, triggering heart attacks and strokes. ¶ But aspirin also has a downside. It can cause ulcers, stomach and intestinal bleeding, and in rare cases life-threatening hemorrhagic strokes, caused by bleeding in the brain. Aspirin can also cause severe allergic reactions, ringing in the ears, upset stomach and heartburn, and some recent evidence has linked it to macular degeneration, which causes vision loss. So it’s important for each person considering aspirin therapy to determine whether the benefits outweigh the risks. In general, the higher your cardiovascular risk, the more likely that aspirin is a good idea.

Aspirin A-list

Daily aspirin almost always makes sense for people in certain groups. Anyone who has been given a diagnosis of heart disease — a buildup of plaque that reduces or blocks blood flow in the arteries feeding the heart — or who has survived a heart attack or experienced a stroke or near stroke (also called a transient ischemic attack, or TIA) should take a daily 81-milligram aspirin tablet for as long as he or she can safely tolerate it. That’s the recommendation of several medical organizations, including the American College of Cardiology and the American Heart Association (AHA).

For people who have had a heart attack or stroke, for example, research shows that daily aspirin cuts the risk of a repeat event by at least 20 percent and the chance of dying from such an event by 10 percent. Even so, you should talk with your doctor before starting aspirin therapy to make sure it’s appropriate for you.

Assessing your risk

Things get less certain when aspirin is considered for people who haven’t received a heart disease diagnosis or suffered a heart attack or stroke but are considered to be at moderate or high risk. That includes people who smoke, don’t exercise or are overweight, as well as those with high blood pressure, high cholesterol, diabetes or a family history of premature cardiovascular disease.

Studies have found that daily aspirin lowers the chance of a heart attack or stroke for such people, but the benefit might be less than for those with known heart disease or a previous heart attack or stroke, and the risk of bleeding remains the same. In general, people who have multiple risk factors for cardiovascular disease — for example, they smoke, have diabetes and have high blood pressure — stand to benefit more from aspirin therapy than people who have one or no risk factors.

To help decide when the benefit of aspirin is worth the risk, medical experts have developed a way to estimate your 10-year risk of having a heart attack or stroke. (You can access a risk calculator free at www.consumerreports.
) But experts disagree about how high the risk should be before considering aspirin. The U.S. Preventive Services Task Force (USPSTF), an independent group that advises the government, says that for men age 45 to 79 and women 55 to 79, the benefits of aspirin outweigh the risks if they have a high risk of having a heart attack or stroke in the next decade. But what the task force considers “high risk” changes with age, from 3 to 4 percent for people 59 and younger to 11 to 12 percent or more for those in their 70s.

Both the American College of Cardiology and the AHA offer a slightly simpler recommendation, advising that men and women consider aspirin if they are 50 or older and their 10-year risk of a heart attack or stroke is higher than 10 percent. Still other experts, including Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic, says that such people should not take daily aspirin unless their 10-year risk is very high — more than 20 percent.

Confused? Several clinical trials are underway that should help clarify exactly who benefits from aspirin. And the USPSTF is expected to issue updated recommendations in 2014 that take into account studies that have come out since its original recommendations in 2009. In the meantime, a good rule is for anyone with a 10 percent or higher risk of a first heart attack or stroke to discuss aspirin with his or her health-care provider.

Bottom line: If you have heart disease or have suffered a heart attack or stroke and don’t currently take aspirin, talk with your doctor about whether you should start. If you’re not in that group and are 45 or older, calculate your risk of a heart attack or stroke in the next 10 years, then discuss with your doctor whether aspirin makes sense.

Copyright 2013. Consumers Union of United States Inc.

For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.