Millions of Americans pop a daily aspirin to help stave off a stroke or heart attack. This is a proven, doctor-recommended way to protect against a major cardiovascular event in people who already have heart disease or are at high risk. But for everyone else, the painkiller offers little if any cardiovascular benefit — and it may do more harm than good. According to a new study, 12 percent of people taking daily aspirin for heart protection are using the drug unnecessarily and therefore putting themselves at risk for gastrointestinal bleeding and brain bleeds, which, ironically, are a type of stroke.
Cardiologists from Baylor College of Medicine analyzed the medical records of almost 70,000 patients who reported using aspirin as prevention. To determine whether patients' aspirin use was appropriate and helpful or unnecessary and hazardous, the researchers assessed each person's likelihood of having a heart attack or stroke within the next 10 years. (They used a risk calculator developed by the American Heart Association that factors in age, gender, blood pressure, smoking history, cholesterol, blood pressure, and other key data.)
"Aspirin use should be based on a person's 10-year risk of having a heart attack or a stroke," says lead study author Salim Virani. "Aspirin should not be prescribed or used if that risk is less than 6 percent." But even 6 percent is a conservative cutoff, he points out, as other guidelines deem aspirin use inappropriate when heart attack or stroke risk is less than 10 percent.
To find out that 12 percent of these patients' risks were well below the 6 percent threshold was surprising and scary to the researchers. "In these cases, the risk associated with aspirin — bleeding in the gut or brain — far outweighs any potential benefit in terms of prevention of heart attack or stroke," Virani says. "Aspirin is not a benign drug as is widely believed. It can cause bleeding from the gut, usually from ulcers. Less common but even more concerning is bleeding in the brain. These risks are real and can be life threatening. For people who do not meet the 6 percent threshold, the focus should be on lifestyle modification for prevention instead of aspirin."
The other alarming fact: There may be even more people taking aspirin unnecessarily than was reported in this study. "Our analyses accounted only for aspirin that was documented on patients' medical charts," Virani says. "Since aspirin is an over-the-counter medication, it's quite possible that some patients were taking it and did not let their provider know, or that the provider did not write it down. Therefore, 'real world' inappropriate aspirin use could be higher than what we found in our study."
So who's to blame for aspirin overuse and misuse? "It's likely a combination of overprescribing by health care providers and patients taking it on their own based on the widespread belief that everyone should take aspirin to prevent heart attacks and strokes," Virani says. "Previous research has also shown that health care providers often do not use the available risk calculators," before prescribing.
Even so, Virani says the best strategy to assess whether or not you should take aspirin is still to discuss it with your doctor. "Your health care provider can give you a good estimate of your chance of deriving the benefit from aspirin versus your risk of bleeding," he says.