Aspirin and Your Heart
Before aspirin was a tiny, white pill known for relieving aches and pains, ancient Sumerians and Egyptians were using willow bark to treat the same issues. Willow bark—along with other fruits, grains, and vegetables—contains salicylic acid, and aspirin is simply a synthetic derivative of this long-used natural substance. While it took until the dawn of the 20th century for aspirin to appear in its more familiar form, it’s been one of the most popular and well-researched drugs ever since.
One such avenue of research is the prevention of heart disease in people with diabetes. While effective for many, aspirin therapy isn’t for everybody. Some general guidelines can help you discuss with your doctor whether you may be a good candidate:
- Anyone with heart disease who isn’t at an increased risk of bleeding. Bleeding risk is higher for people with a history of a major bleed and those taking corticosteroids, like prednisone, or regular nonsteroidal anti-inflammatory drugs, or NSAIDs, like ibuprofen and naproxen.
- People older than 50 who have diabetes and at least one additional heart disease risk factor, such as a family history of heart attack or stroke, high blood pressure, or a smoking habit
- People whose heart disease risk is greater than 10 percent (your doctor can calculate this for you)
- People under 50 with diabetes who have a heart disease risk of 5 to 10 percent
- People younger than 50 who have diabetes but no additional risk factors
- People whose heart disease risk is less than 5 percent
Aspirin at Work
When plaque, which is a buildup of cholesterol and fatty substances, ruptures inside an artery, the body forms a larger-than-necessary blood clot, which can block the vessel. A blocked coronary artery can lead to heart attack, while blocked blood vessels in the brain can result in ischemic stroke (“ischemic” refers to a lack of blood supply). “Aspirin works by inactivating our platelets, which are very important things that cause our blood clotting in those plaques,” says Michael Pignone, MD, MPH, FACP, a professor of medicine at the University of North Carolina–Chapel Hill and a member of the U.S. Preventive Services Task Force. “So [aspirin] reduces the chance of there being any blockage and therefore reduces the chance of a heart attack or stroke.”
But there is a downside: Because aspirin stops the blood from clotting as efficiently, it also increases the risk of uncontrolled bleeding. This can lead to gastrointestinal bleeding and a less common form of hemorrhagic—or bleeding—stroke.
Aspirin therapy is used in two ways: to prevent heart disease in people who have never had a cardiovascular event, such as heart attack or stroke, and to prevent another cardiovascular event in people with established heart disease. There is an important distinction between these two, says Mikhail Kosiborod, MD, FACC, chair of the American College of Cardiology’s Diabetes Collaborative Registry and a cardiologist at Saint Luke’s Mid-America Heart Institute in Kansas City, Missouri. Studies have shown that aspirin therapy significantly benefits people with heart disease. Although bleeding is still an increased risk, Kosiborod believes it’s far outweighed by the potential to prevent additional heart problems.
Studies involving aspirin therapy in people with diabetes who have no established cardiovascular disease are a lot less convincing in terms of the benefits of aspirin, says Kosiborod. On top of that, such individuals are still at risk for a bleeding event (the risk for bleeding increases with age).
The bottom line: Treatment has to be individualized for each person. “We can make recommendations,” Pignone says. “But patients need to talk with their doctors about the best decision for them because it is fairly finely balanced.”
The Diabetes Difference
Research shows that aspirin therapy for people without established cardiovascular disease works equally as well in people with and without diabetes.
There is one important distinction, however. People with diabetes have more reactive, or “sticky,” platelets, which form blood clots more easily. This is caused by high blood glucose, along with other factors, such as inflammation, insulin resistance, high blood pressure, and obesity.
“You would think that if patients with diabetes had more active platelets, maybe they would get a greater benefit from aspirin,” Kosiborod says. But that does not appear to be the case. It may be that inhibiting sticky platelets requires something stronger than aspirin.
Overall, aspirin therapy appears to be more effective in preventing heart attack than stroke in men, according to Kosiborod. But Pignone says these results are based on limited evidence.
Only a few important studies have looked at aspirin therapy in women without heart disease for the prevention of cardiovascular events. One of these, the Women’s Health Study, provided women with 100 milligrams of aspirin every other day, the lowest dose in any of the trials involving people without heart disease. It discovered that aspirin therapy was more effective in treating stroke than heart attack in women.
More research is needed, but studies have shown that aspirin doesn’t seem to affect men and women with heart disease differently.
Off the Table
Certain people should not take daily aspirin because the risks would clearly outweigh the benefits. “If you’ve had a recent major bleeding event—either a bleeding stroke in the brain or a major gastrointestinal bleed—or if you’re allergic to aspirin, then aspirin wouldn’t be a good choice,” says Pignone. Aspirin should not be used by people under 21 because of the risk for a rare disorder called Reye’s syndrome.
The recommended dose of daily aspirin is between 75 and 162 milligrams, which is considered a low dose. (Baby aspirin is 81 milligrams.) Evidence shows that low-dose aspirin has the same benefits as higher doses and may have slightly fewer adverse effects, such as bleeding. But it’s important to remember that any dose still has risks. “There is not a dose that we know of that brings the benefits but eliminates the harms,” Pignone says.
Two ongoing clinical trials are studying the effects of aspirin therapy in people without established cardiovascular disease who have diabetes, which will shed more light on its effectiveness.
ACCEPT D—Researchers are collecting data on 4,700 men and women ages 50 and older with type 1 or type 2 diabetes without established heart disease. This randomized trial is looking at aspirin and statins for preventing heart attack and stroke.
ASCEND—This randomized, double-blind trial is studying 15,480 men and women ages 40 and older with type 1 or type 2 diabetes who have no previous history of heart disease. Researchers will measure how well aspirin and omega-3 fatty acids prevent heart attack and stroke.
Talk Like a Doc
Primary Prevention: Treatment, such as aspirin therapy, intended to keep a health event or disease from happening in the first place
Secondary Prevention: Treatment usedto prevent the recurrence of a health problem, such as a heart attack
Disclaimer: The views of Michael Pignone, MD, MPH, FACP, are his own, not those of the U.S. Preventive Services Task Force.
Disclosure: Mikhail Kosiborod, MD, FACC, receives research support from and is a consultant for AstraZeneca.