Many patients prescribed aspirin therapy don't need it

Like millions of Americans, Brian Hull has high cholesterol and a family history of heart disease. He takes low-dose aspirin every day to reduce his chance of a heart attack.

"The concern was I not have a heart attack like my father did," he told CBS News. Hull, 57 years old, said he believes aspirin maintenance therapy has prevented him from having any episodes of cardiac arrest over the last decade. "Knock on wood, I haven't had one yet and I'm hoping I won't have one forever!"

However, a new study in Journal of the American College of Cardiology finds more than 10 percent of patients who are being prescribed aspirin to prevent a first-time heart attack or stroke, should not be taking the medicine. While aspirin can help thin the blood in order to prevent blood clots, researchers say, for many patients, taking aspirin could do more harm than good.

"You can have risk of bleeding in your stomach, you can even have a stroke that can cause a certain kind of bleeding inside your brain," Dr. Ravi Dave, a cardiologist at the UCLA Medical Center in Santa Monica, told CBS News.

For the study, researchers from Baylor College of Medicine in Houston looked at 68,000 patients and calculated each one's risk for developing heart disease over the next decade. For each person, the researchers looked at factors such as age, gender and blood pressure. The study didn't look at patients with a history of cardiovascular disease, since they benefit most from aspirin to prevent heart attacks. The researchers found that patients who were considered low-risk should not take aspirin. They also found that 17 percent of women were taking aspirin unnecessarily, compared with 5 percent of men.

Other recent studies have confirmed that when it comes to aspirin maintenance therapy sometimes the risks outweigh the benefits, especially for women.

One study, published in the journal Heart involved nearly 28,000 healthy women age 45 and older, who were given either 100 milligrams of aspirin every other day or a placebo. A decade and half later, the researchers found regular aspirin only modestly reduced the risk for cancer and cardiovascular disease. However, a sizable number of women in the study suffered from long-term gastrointestinal bleeding.