More than 1/3 of U.S. heart-attack and stroke survivors don't take aspirin to prevent a second one, 40 years after it was first advised

People who have experienced a heart attack or stroke have prevented another one from happening by taking a daily aspirin. But fewer than half of heart attack or stroke victims worldwide take the inexpensive medication, according to a study in the Journal of the American Medical Association.

“Survivors of heart attacks and stroke often face a high risk of having subsequent events,” said lead researcher Dr. Sang Gune Yoo,  a cardiovascular disease fellow at the Washington University School of Medicine in St. Louis. “In fact, many people die from having recurring attacks. Aspirin offers one effective and relatively low-cost option for reducing the likelihood of additional events in individuals with established cardiovascular disease, and yet most people who could benefit from a daily aspirin don’t take it.”

Graphic by Mike Worful, Washington University, adapted by Ky. Health News

For more than 40 years, research has established that aspirin can reduce the risk of a second heart attack or stroke, by about 25 percent. But more than a third of survivors in the United States and other high-income countries do not take it, according to the study, which looked at a wide range of countries. Generally, the lower a country's average per-capita income, the less likely survivors were to take aspirin; in low-income nations, only 17% do.

The study didn't explain those figures, but Yoo said likely reasons include varying access to health care, inconsistent messaging surrounding use of the drug, and the fact that aspirin is a prescription drug in some countries.

Aspirin is a blood thinner, preventing small blood cells called platelets from forming clots. These clots can block arteries and contribute to a reduction in the amount of oxygen-rich blood being delivered to vital organs. Such blockage also can cause other complications, including a heart attack or stroke.

The study notes that cardiovascular disease, including heart attack and stroke, is the world's leading cause of death. Contributing factors include smoking, diabetes, unhealthy diet, genetics, lack of exercise, obesity and air pollution. 

The researchers analyzed data from nationally representative health surveys in 51 countries. The surveys included questions about people’s medical history of cardiovascular disease and on aspirin use. The study included 125,505 people, with 10,590 self-reporting a history of cardiovascular disease.