Dueling Docs: Is it worth taking aspirin to prevent a heart attack?

11/19/2009 04:12 pm ET | Updated May 25, 2011

The Issue
Daily aspirin and heart disease

The Facts
Kids are told that an apple a day keeps the doctor away, but for many grownups the message is quite different. They're told that an aspirin a day keeps the heart attack away. Indeed, today some 50 million Americans pop a baby aspirin (81 milligrams) once daily to ward off heart disease. Should they?

Nearly all doctors agree that for people who've already had a heart attack or stroke, a low-dose aspirin will help prevent another cardiovascular event. But doctors also routinely recommend aspirin for what's called primary prevention, that is, for people who've never had a heart attack or stroke, but who have common risk factors such as high cholesterol, diabetes or high blood pressure.

These folks may feel like ticking time bombs, but a recent report suggests they're probably better off leaving those aspirins in the medicine cabinet. Earlier this month, editors at Drugs and Therapeutics (DTB), a publication of the British Medical Journal, said that the risks of taking a daily aspirin outweigh the benefits for those who've never had a stroke or heart disease. They explain that the same mechanism that makes aspirin so beneficial--it reduces the stickiness of blood and therefore helps block the formation of dangerous blood clots--is also what makes it risky. By making the blood thinner, they say, aspirin can lead to gastrointestinal bleeding or a type of bleeding in the brain known as a hemorrhagic stroke.

Yet, many U.S. doctors still see the benefit in those little white pills, even for those who've never had an actual heart attack.

What should you do? Two doctors debate the issue: Ike Iheanacho, M.D, editor of the British Medical Journal's Drugs and Therapeutics Bulletin and Clyde Yancy, President of the American Heart Association and medical director of the Baylor Heart and Vascular Institute at Baylor University Medical Center in Dallas, Texas.

The Debate

Dr. Ike Iheanacho:

"A lot of physicians will swear by aspirin for primary prevention, for preventing the first heart attack or stroke. I don't think they're bad people, but we've got a difference of opinion on the evidence. In the UK, our guidelines advise the use of aspirin for people who haven't had a heart attack or stroke yet but who may have diabetes, high cholesterol or high blood pressure. We are challenging this."

"We looked at the broad sweep of evidence accumulated over more than 20 years and our reading is that you can't actually show that using aspirin affords a net benefit to these people, particularly those who have diabetes or high blood pressure. Any benefit is small and largely offset by the risk of aspirin, which includes bleeding from the gut. The use of aspirin routinely, almost unthinkingly, should be put into question."

One piece of evidence that Iheanacho cites is an analysis of six controlled trials involving a total of 95,000 patients and published earlier this year in the journal the Lancet. It concludes that a baby aspirin for heart-healthy people nearly doubles the odds of being admitted to the hospital with serious gastrointestinal bleeding, while its impact on curbing death rates from heart attack or stroke is negligible. "Basically, says Iheanacho, "the study shows that you have to treat 2,000 people a year with aspirin to prevent a single heart attack. But, every time you treat 3,300 people you got a gastrointestinal bleed. What the two statistics are showing is that the benefit of taking aspirin is pretty small. Some may hear this and ask themselves why they are being treated with a drug that's not doing much good."

Moreover, gastrointestinal bleeds are not to be taken lightly. "When you talk about stomach bleeding, it can sound trivial, but it is a killer. The most minor heart attack could be a less of a problem than a big stomach bleed. If the bleed is severe enough, it is as deadly as having a heart attack or stroke. These risks should not be dismissed."

Iheanacho allows that "doctors can still decide to put somebody on aspirin for primary prevention. They could still say the risk of a bleed isn't high enough, especially for someone with a family history of heart attack who really worries about it. But we don't believe people should just routinely be put on aspirin because they have diabetes, high cholesterol or elevated blood pressure."

Dr. Yancy:
"Others would look at the very same data base and come to a different conclusion. We still believe that for certain patients, there is an absolute benefit for taking a baby aspirin for primary prevention."

Are you one of those patients? The good news, says Yancy, is that it's easy to answer that question by using a personal risk assessment tool found online at the National Lung and Blood Institute:

"It takes a minute to fill out and it will tell you right away whether or not the American Heart Association considers you to be somebody who should be on a baby aspirin for primary prevention of a heart attack or stroke," says Yancy. "It's easy. If the tool tells you that your risk of heart disease is greater than 10%, then, yes, you should be taking an aspirin. Someone who only has high blood pressure may not benefit from aspirin, which is keeping with the British analysis. But, say, you're a man 55 or older who smokes and your cholesterol is greater than 220 with HDL cholesterol less than 50 and your blood pressure is 150, then your risk of disease over the next 10 years for heart attack and stroke is 20%, or a one in 5 chance. You should be on a baby aspirin. Here the risk of preventing disease overwhelms the risk."

"But the fact is, people can reach that 10% threshold pretty easily. A smoker with a nice cholesterol of 190 - would still need to be on aspirin."

Yancy also departs from the British conclusion regarding diabetes. "We believe that someone with diabetes has the same risk of having a heart attack as someone who has already had a heart attack. We think of ourselves in America as something of world leaders on this issue and we treat the diabetic patient as if they've already a heart attack. In other words, unlike the findings of the British researchers, we think diabetics should be on a baby aspirin."

Same for people with hardened arteries. "If you have clogged arteries, we're not talking about primary prevention anymore. We look at this disease as if you've had a heart attack. You, too, should be on a baby aspirin."

Yancy also points out that age is a big factor in cardiovascular disease, but less of a factor when it comes to stomach bleeds. "Age really does begin to increase the likelihood of disease. The older you are, the risk of heart disease and stroke go up significantly, but not to the same extent as for gastrointestinal bleeding or hemorrhagic stroke."

Finally, Yancy is quick to point out that there are many ways to prevent heart disease, not just by popping an aspirin each day. "Aspirin is not the end all be all for heart disease prevention. You can't change your age or your gender, but you can certainly lower your risk of heart attack by getting your cholesterol down, quitting smoking and keeping your blood pressure under control. Even if you qualify to take a baby aspirin, you should still take these other healthy steps, too."