New recommendations could affect millions of people.
You may remember a time when taking a daily baby aspirin was almost a rite of passage for generally healthy older adults. The idea was that, for people with a low to moderate risk for heart disease, aspirin therapy was a simple and cost-effective way to help prevent a heart attack or stroke.
But taking aspirin increases the risk for bleeding in the stomach and brain (see "How aspirin affects the body").
For people who've already had a heart attack or stroke, the benefits of aspirin clearly outweigh the bleeding risks. However, doctors have spent the past 10 years questioning if the same is true for everyone else.
Earlier this year, the debate came to a screeching halt, particularly for older people.
How aspirin affects the body
Aspirin reduces the blood's ability to clot. That helps reduce the risk of blood clots forming inside an artery and blocking blood flow in the heart (causing a heart attack) or in the brain (causing a stroke). That's the benefit of aspirin.
The risk from aspirin is that it increases the tendency to bleed, especially in the stomach but also (rarely) in the brain.
Aspirin increases the risk of bleeding in the stomach by blocking chemicals called prostaglandins, which protect the stomach lining.
In March, the American Heart Association (AHA) and the American College of Cardiology (ACC) recommended against the routine use of low-dose (81-mg) aspirin in people older than 70 who do not have existing heart disease and haven't had a stroke, or in people of any age who have an increased risk for bleeding (from a peptic ulcer, for example, with sores on the stomach lining that can bleed).
"It's a big shake-up, based on three large studies. Two of the three showed there was no benefit to taking daily aspirin to prevent a first heart attack or stroke, and aspirin was associated with an increased risk for bleeding severe enough to require transfusions or hospitalization. The other study showed that in people with diabetes but no cardiovascular disease, there was benefit, but also risk: a 1% reduction in heart attack risk, and a 1% increase in bleeding risk," explains Dr. Christopher Cannon, a cardiologist at Harvard-affiliated Brigham and Women's Hospital.
The guideline changes for aspirin use will affect millions of people. A Harvard study published online July 22, 2019, by Annals of Internal Medicine suggested that about one-quarter of people ages 40 or older without cardiovascular disease -- 29 million people -- are taking aspirin each day.
Among those people, 23% (6.6 million) are taking aspirin without a doctor's recommendation, possibly putting them at an increased risk for bleeding without sufficient benefit.
What you should do
There's no debate about aspirin use among people who've already had a heart attack or stroke, people who have peripheral artery disease, or people who've had bypass surgery or had a stent inserted in their coronary arteries. For them, aspirin therapy is a cornerstone of treatment. "We accept the risk of bleeding in these cases, because the risk of another heart attack, stroke, or death is higher," Dr. Cannon says.
But the decision to use aspirin therapy in people ages 40 to 70 is more complicated. It requires calculating your individual risk for problems caused by arteries clogged by atherosclerosis (mainly having a heart attack or stroke) in the next 10 years. Risk factors include
- age (risk increases each year after 50)
- being male
- being African American
- history of high blood pressure
- cigarette smoking
- unhealthy cholesterol levels.
"A 10% risk may make you a candidate for aspirin therapy. But we can't make a general statement for treatment if you have a lower risk," Dr. Cannon says. You can estimate whether your risk is above or below 10% by using the AHA and ACC risk calculator (www.cvriskcalculator.com).
If you've been using aspirin regularly for years, don't stop taking it. Likewise, don't start taking it just because you think it will help you. In either case, do talk to your doctor.
"Aspirin therapy is an important treatment that should be discussed with your physician," Dr. Cannon notes, "and it should be a shared decision."