Anywhere from 40% to 60% of older people take daily aspirin to prevent a heart attack or stroke. Studies have shown that low doses of the blood-thinner can significantly lower the risk of heart problems, especially among people who have already had a heart attack or stroke.
But in a study published in the Lancet, researchers say that the risks of aspirin haven’t been properly studied in older people. Most of the studies showing the over-the-counter drug’s benefits have included younger people under 65 years. However, most people who are currently taking daily aspirin for their heart are older.
In the study, Peter Rothwell, professor of neurology at the University of Oxford, and his colleagues analyzed data from the Oxford Vascular Study, which followed more than 3,000 people who had had a heart attack or stroke and were given aspirin or other anti-clotting drugs by their doctors. After 10 years, Rothwell found that ulcers and bleeding events—a common side effect of aspirin—were more common among people over 75 than those under 65.
Once the bleeding events occurred, most commonly in the stomach or digestive tract, the bleeding was more intense and severe in older people than in younger people.
“The overall increased risk for older people surprised us,” says Rothwell. “And the proportion who did have major consequences from the bleeding also surprised us. We were surprised by the extent to which the bleeds were causing disability and even death.”
About 1.5% of the people in the study under age 65 were admitted to the hospital for bleeding problems, compared to 3.5% for those aged 75-84 and 5% for people over age 85. The risk of having disability or even dying after a bleeding event because of complications was 10 times higher for those over age 75 than for younger people.
In fact, says Rothwell, for older people, the risks associated with bleeding were actually higher than the risk of having a heart attack or stroke, which the aspirin was supposed to prevent.
The data point to an increasing disconnect that doctors are experiencing when they see older patients. While aspirin is generally regarded as safe, and the risk of bleeding is often considered minor and easily addressed, that's not the case among older people. “In our clinical experience, for people in their 80s and 90s, bleeds can actually be devastating,” says Rothwell. “People sometimes don’t regain their mobility, they can develop delirium, they go to the hospital and never regain the same level of cognitive function. There’s been an assumption in the past that all bleeds from aspirin are like pests and dismissed as not a major problem, but perhaps that’s not so true in the elderly.”
Fortunately, there is a way to offset the risk of bleeding from aspirin: by prescribing a proton pump inhibitor, a class of drugs that reduces the amount of acid, which can contribute to bleeding, produced by the stomach. Studies show that they can reduce bleeding events by up to 90% in the tract. But doctors have been reluctant to add another drug to an elderly person’s typically long list of medications, and the practice of viewing aspirin-related bleeds as minor also means that the risks of bleeding aren’t being addressed properly.
The study’s findings add more information to the growing discussion about the safety of daily aspirin. Recent studies found that older people taking low doses of aspirin every day can lower their risk of not only heart disease but certain cancers, due to the drug’s inflammation-reducing effect. But Rothwell’s data should encourage patients to ask their doctors about whether they would benefit from daily aspirin—or suffer more from side effects. The risk-benefit equation may be different for people who have already had a heart event, compared to those who may be at risk of having a heart attack and want to prevent that from happening. The American Heart Association and the U.S. Preventive Services Task Force currently recommend daily aspirin for people who have not yet had heart problems, but only if they are at particularly high risk of having an event. The Food and Drug Administration, on the other hand, does not recommend that people who have not yet had a heart event take aspirin on a daily basis to prevent a first-time event.
If you are already taking daily aspirin after a heart attack, or in an effort to prevent your first one, Rothwell does not recommend that you stop immediately, since that can also cause a rebound effect that could be bad for your health. But he says it might be worth discussing with your doctor whether adding a proton pump inhibitor would make sense to protect you from the potentially dangerous side effects of bleeding.