Too many people are making the wrong choice…

It seems harmless enough…popping an aspirin from that familiar little bottle tucked away in your medicine cabinet.

In fact, millions of Americans take an aspirin daily as a blood thinner to help prevent the artery-clogging blood clots that cause most heart attacks and strokes. But for many of these people, aspirin is doing more harm than good.

Recent finding: In a study of 68,800 adults taking daily aspirin therapy for heart attack and/or stroke prevention, nearly 12% were doing so unnecessarily based on their limited chances of actually suffering from one of these conditions over the next decade. In doing so, these individuals were found to be increasing their risk for potentially dangerous side effects, such as internal bleeding, for no good reason.

A tragic toll: Among the more than 16,000 deaths each year linked to bleeding associated with use of nonsteroidal anti-inflammatory drugs (NSAIDs), about one-third of these deaths occur in those who take low-dose (81-mg) aspirin.

IS ASPIRIN RIGHT FOR YOU?

You may assume from these frightening statistics that aspirin is never worth the risk, but that would be a mistake. Whether you’re trying to prevent a heart attack, stroke or cancer, to make the best decision about using aspirin, you and your doctor need to weigh your potential benefits against your potential harms and then make a choice based on your preferences. When aspirin use may help…

HEART ATTACK OR STROKE

If you’ve already had coronary bypass surgery, a heart attack or ischemic stroke (caused by a blood clot), taking aspirin and/or another blood-thinning drug, such as clopidogrel (Plavix) or warfarin (Coumadin), is wise. That’s because study after study shows that aspirin significantly reduces the risk for a second heart attack or stroke. (A person whose risk for bleeding is extremely high may be an exception.)

If your goal is to prevent a first heart attack or stroke, the decision is a bit more complicated. Guidelines from the American Heart Association (AHA) and the US Preventive Services Task Force recommend aspirin for primary prevention in people at high risk for cardiovascular disease. In 2014, the FDA weighed in, releasing a statement that warned against widespread use in people of average risk.  

My advice: I advise some—but not all—of my male patients who are over age 45 to take aspirin for primary prevention. For women, I advise aspirin for most who are age 65 and older. There are exceptions, especially for those who are at high risk for bleeding. Meanwhile, men and women younger than these ages sometimes have enough risk factors for heart attack and stroke that they will benefit from aspirin.

Scientific evidence: An analysis of multiple studies published in The Journal of the American Medical Association, involving nearly 100,000 people, showed that daily aspirin can decrease heart attacks in men age 45 and older by 32%. In women, research has found that the greatest benefit—for reduction in ischemic stroke and heart attack—occurs for those age 65 and older.

What’s my criteria for recommending aspirin? If the patient’s chance of having a heart attack or stroke in the next 10 years is higher than 5% to 10%.

To determine your heart attack and stroke risk: Use the cardiovascular disease (CVD) “risk calculator” created by the American College of Cardiology and the AHA. To download the calculator onto your computer or an app onto your smartphone, go to My.AmericanHeart.org (click on “Statements & Guidelines,” then on “Prevention Guidelines”).

If your risk is above 5% to 10%, talk to your doctor about whether you should be taking aspirin.

Important: Once you have your result from the risk calculator, you must balance your potential benefit from taking aspirin to prevent a heart attack or stroke against possible harm. Have you had gastrointestinal (GI) bleeding in the past? Are you regularly taking another anti-inflammatory medicine such as ibuprofen (Motrin), which also increases your risk for GI bleeding?

Are you age 80 or over? Aspirin might help you, but there’s no solid evidence to guide your decision. Nonetheless, older adults have the most to gain from aspirin, but need to be particularly careful to avoid bleeding problems.

PREVENTING CANCER

In weighing your decision to take aspirin for heart attack and stroke, you also may want to take into account recent research showing that aspirin may help prevent cancer—and perhaps even extend the lives of people who have had a malignancy.

Landmark findings: When researchers at the University of Oxford analyzed dozens of studies on aspirin, they found that regular use of the medicine may help prevent cancer—with a 38% reduction in the risk for colon cancer and similar reductions in breast, esophageal and stomach cancers.

Note: There is some debate about whether low-dose aspirin is always enough, and it appears to take years of aspirin use to see a reduction in risk.

According to a study published in 2014 in Anticancer Research, regular aspirin users who had colon cancer were 60% less likely to have a recurrence or to die from the disease than colon cancer patients who weren’t taking aspirin. Researchers theorize that cancer cells may spread throughout the body behind a protective shield of platelets—and aspirin may disrupt that process.

What this means for you: If you’re a man over age 45 or a woman over age 65…and considering taking aspirin for primary prevention of a heart attack or stroke…and your risk for cardiovascular disease is “borderline” (around a 5% chance of having a heart attack or stroke in the next 10 years, according to the calculator)—your desire to prevent cancer (particularly colon cancer) may tip the scales in favor of regular use of low-dose aspirin.

With this level of evidence, however, no one should take daily, low-dose aspirin solely for the purpose of preventing cancer.