Rethinking the aspirin a day therapy
Millions of healthy elderly Americans take a low-dose aspirin tablet very day in the hopes of preventing future cardiovascular disease and stroke. It seems harmless enough, but is it really safe?
A recent series of studies concluded that the habit may be causing more harm than good, for most people.
The news came out of the ASPREE trial (Aspirin in Reducing Events in the Elderly), which asked exactly that question. Researchers looked at more than 19,000 healthy people ages 70 and older. They gave half of the participants a 100-milligram dose of aspirin and the other half a placebo, for an average of 4.7 years.
The news that the study found troubling new questions about taking a daily aspirin prompted patients to flood their doctors’ offices with questions, according to cardiologist Lawrence McAuliffe, MD, of Cape Cod Healthcare Cardiovascular Center in Hyannis. He received three calls before 8:30 a.m. the day the news was announced, so he looked up the studies and read them carefully
He believes the study showed that for most people, a daily aspirin is not necessary, but it is still advised for certain patients.
“Without a good indication for aspirin there probably is no good reason to take it in a preventive fashion,” Dr. McAuliffe said.
“The study showed that with the patients taking aspirin there were fewer cardiac events per 1,000, but they didn’t reach sufficient statistical significance to overcome the statistically significant risk of the aspirin.
“You always want the benefit to outweigh the risk. So, in that specific group of people, the elderly, it didn’t make sense and it probably also doesn’t make sense for younger patients as well, unless you can demonstrate a significant cardiovascular risk.”
Some Should Take Aspirin
Patients who could potentially benefit from a low-dose aspirin every day are those who are at high risk for a primary cardiac event, even if they haven’t already had one, he said. Cardiologists use cardiovascular risk calculators that take in a panoply of risks an individual may have.
- Risk factors that might indicate aspirin therapy include:
- Being overweight
- Having uncontrolled hypertension
- Having peripheral vascular disease
- Having diabetes
Studies show that even if they don’t have any other risk factors, the risk of a future cardiovascular event for insulin-dependent diabetics, especially women, is extraordinarily high, according to Dr. McAuliffe.
The study sought to answer whether a daily aspirin can play a role in the prevention of first-time cardiac events in the elderly, said Dr. McAuliffe. The premise of the study is that the role of aspirin therapy in “functional outcomes,” which are very important to most patients, especially elderly patients,” he said.
The primary endpoints were freedom from cognitive impairment and freedom from physical disability.
Dr. McAuliffe noted that the study subjects were given a 100-milligram dose of aspirin, while the standard recommended dose is 81 milligrams...
“So, before you even look at the results, we’re looking at an older population that was only studied for a medium of four and a half years, who got a higher dose of aspirin than the usual dose,” he said.
Despite those things, the results appear valid to him. Those taking aspirin did have about five percent fewer cardiac events, but a 38 percent increased risk of bleeding.
“The important message, and I think it’s statistically legitimate and it’s been backed up by the studies, is that without a clear indication based upon risk factors, there’s no role for aspirin - certainly not in 100 milligrams - for primary prevention to prevent the first cardiovascular event.”
Don’t Stop Suddenly
When considering the significance and application of the studies, it’s important to understand the difference between primary prevention and secondary prevention, said Dr. McAuliffe. Primary prevention is taking an aspirin a day as a kind of vaccination of sorts to avoid a future problem. Secondary prevention is taking an aspirin for its antiplatelet effect if you’ve already had a heart attack, stroke or undergone procedures such as a bypass, surgery on a valve or a stent.
“We’re trying to secondarily prevent another event. So, in those individuals, aspirin clearly is indicated to continue - case closed,” he said. “Statistically we know that it does reduce risk of a subsequent event.”
For those already taking a low-dose aspirin as recommended by their cardiologist, there can actually be danger in stopping abruptly. A study published in the American Heart Association’s journal Circulation earlier this year showed that suddenly stopping aspirin therapy increased the risk of suffering a cardiovascular event, such as a heart attack or stroke, by 37 percent. The study included more than 600,000 patients over a three-year period in Sweden.