DEAR DOCTOR K: What are the risks of taking a daily aspirin to reduce the risk of a heart attack or stroke?
DEAR READER: I didn’t have to do much homework on this one, because I take a daily aspirin and already know the answer.
It was front-page news in 1988 when colleagues of mine at Harvard Medical School reported the results of a randomized trial that found that a daily aspirin protected against heart disease. A simple, cheap, over-the-counter pill could protect against the No. 1 cause of premature death: heart disease (specifically, atherosclerosis of the arteries of the heart)? It seemed too good to be true.
In my opinion, it now is well established that daily aspirin protects people who have heart disease, or are at high risk of developing heart disease. It reduces their risk of future heart problems. If you have heart disease, or have had the most common kind of stroke (the kind caused by a blood clot), taking a low-dose (81-milligram) aspirin every day is probably a wise move.
But for the average adult (of either sex) who is not at high risk for heart disease, the value of daily aspirin is less clear. Every medicine that has benefits also has risks, which is what your question points out.
Most heart attacks and strokes happen when a clot blocks blood flow in a vessel that feeds the heart or brain. Aspirin helps prevent these clots from forming. That’s the benefit of a daily aspirin.
But any medicine that makes blood clots less likely to form is likely to increase the risk of bleeding. That’s surely true of aspirin, although less so with low-dose aspirin than with a daily full-strength aspirin pill (325 mg).
In addition to lowering the blood’s ability to clot, aspirin also irritates the stomach’s delicate lining. This can cause gastrointestinal (GI) bleeding. For people who are at high risk for GI bleeding — because of lifestyle practices such as heavy drinking, or diseases that increase the risk of GI bleeding — the risk may outweigh aspirin’s benefits.
Taking aspirin with food can help. So can drugs to treat heartburn, which help protect your stomach. Daily aspirin users can also lower their risk of GI bleeding by avoiding nonsteroidal anti-inflammatory (NSAID) drugs such as ibuprofen and naproxen. If you drink alcohol, do so in moderation.
What about the type of aspirin? Enteric coating prevents the aspirin from fully dissolving until it reaches the intestine. That’s supposed to lessen stomach upset. Buffered aspirin combines aspirin with an antacid to “soothe the stomach.” However, to make a long story short, enteric-coated aspirin and buffered aspirin probably don’t reduce the risk of GI bleeding.
There’s also evidence that not all the aspirin in coated pills gets into your bloodstream. This can compromise its heart benefits. Your best bet may be to take chewable low-dose aspirin. You may remember it from childhood as orange-flavored “baby” aspirin.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.