Although aspirin is one of the most extensively studied drugs in medical history, researchers continue to make new discoveries about its risks and benefits for preventing cardiovascular disease (CVD), which kills 2,150 American a day, one every 40 seconds.
Also known as acetylsalicylic acid (ASA), aspirin’s origins date back to 2000 BC, with references to medicines made from salicylate-rich plants (such as willow) appearing in ancient Egyptian papyri. In 400 BC, Hippocrates advised willow bark to treat aches and pains and as an analgesic during childbirth.
New Uses for a 4,000-Year-Old Drug
A late 19th century effort to make the pills less bitter (and therefore more palatable) through the acetylation of salicylic acid inadvertently gave ASA a unique property with important implications for heart attack and stroke prevention, reported a recent paper in Journal of the American Medical Association.
Unlike other nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit the same enzyme, cyclooxygenase (COX), aspirin does so irreversibly. As a result, blood platelets become less sticky, reducing the risk that they will clump into a blood clot that could trigger a heart attack or stroke–an effect that lasts for several days after a single dose.
Pooled data from about 200 trials in patients with known CVD found that daily low-dose use cut risk for major cardiovascular events by more than 20 percent. Aspirin users may also have lower risk for cancers of the colon, pancreas, stomach, lungs, breast, esophagus and prostate, according to data from randomized trials involving 25,570 patients, published in Lancet.
Taking the drug daily has also been linked to better memory and mental functioning in older women at high risk for CVD. However, aspirin also has a downside: increased risk for GI bleeding and hemorrhagic strokes. In addition, its effectiveness varies from person to person.
Aspirin-insensitive individuals are twice as likely to have a cardiovascular event. Potential causes for aspirin ineffectiveness include high cholesterol, pre-diabetes/diabetes and use of other NSAIDs. A simple urine test, Aspirinworks™, can help physicians assess patients’ response to ASA therapy.
Nearly 12 Percent of Patients May Take Aspirin “Inappropriately”
In a new study of 68,808 patients being treated by American cardiologists, 7,972 were taking daily aspirin despite having a very low risk for heart attacks and strokes over the next 10 years. The researchers concluded that 11.6 percent of the patients were receiving the drug “inappropriately.”
The study, which was published in Journal of the American College of Cardiology, examined medical records from the American College of Cardiology’s PINNACLE registry, focusing on patients taking the drug for primary prevention. Researchers from Baylor College of Medicine and other centers calculated the patients’ ten-year risk for heart attack by using the Framingham CVD Risk Assessment Tool.
Other key findings:
- Nearly 80 percent of the patients taking the drug when their risk factors didn’t warrant it were women.
- In the 119 cardiology practices studied, rates of inappropriate aspirin use ranged from 71.8 percent in some practices to zero percent in others.
- Younger patients (ages 49.9 to 65.9 years) were more likely to receive aspirin inappropriately than older people.
When Is Aspirin Recommended for Heart Attack and Stroke Prevention?
Guidelines from the American Heart Association (AHA) for primary prevention of CVD and stroke advise aspirin for patients with a ten-year risk of 10 percent or more. The AHA and American Stroke Association recommend the drug for primary prevention of stroke if ten-year risk is at least 6 to 10 percent.
The researchers defined aspirin use as inappropriate if ten-year risk was less than 6 percent, and also noted that because the drug is available over the counter, patient (rather than medical provider) preference may be partially driving unwarranted use of the medication.
“Our findings suggest that there are important opportunities to improve evidence-based aspirin use for the primary prevention of CVD,” the researchers concluded. Patients shouldn’t take aspirin or other over-the-counter medications without discussing the potential risks and benefits with their medical provider.