A new study found that 12 percent of patients who take aspirin to avoid a heart attack or stroke are taking it "inappropriately."

Aspirin therapy was introduced in the 1970s as a treatment to prevent and manage heart attacks with the belief that it can significantly reduce heart damage during a heart attack. It is also believed to reduce the risk of stroke. Doctors usually prescribe a daily intake of 325 mg of aspirin for those who need the therapy. However, a new study suggests that some patients taking it are not doing it as they should.

Researchers at Baylor College of Medicine in Houston looked at the data of almost 69,000 patients receiving aspirin for heart disease and stroke prevention. Based on the guidelines for aspirin use of the American Heart Association and other organizations, aspirin should not be taken by those who have a risk of less than six percent. But initial analysis showed that almost 12 percent of the participants are not following this guideline.

On a positive note, the rate of aspirin misuse has declined by five percent between 2008 and 2013. More women are taking it inappropriately at 17 percent, compared to five percent of men.

The researchers warned patients that using aspirin inappropriately can increase one's risk to stomach ulcers, abdominal bleeding, or bleeding into the brain during stroke.

"Medical providers must consider whether the potential for bleeding outweighing the potential benefits of aspirin therapy in patients who don't yet meet the guidelines for prescribing aspirin therapy," said the study's lead and senior author, Ravi S. Hira, M.D. and Salim S. Virani, M.D., Ph.D., of the Baylor College of Medicine in Houston, in a press release. "Since aspirin is available over the counter, patient and public education against using aspirin without a medical provider's recommendation will also play a key role in avoiding inappropriate use."

Last year, the U.S. Food and Drug Administration released an advisory that daily aspirin therapy should be employed only after a health care professional weighs the benefits and risks. If the medical expert eventually recommends taking aspirin daily in order to reduce certain risks of heart attack and clot-related stroke, one should start reading the labels carefully.

This study was published in the Jan. 12 issue of the Journal of the American College of Cardiology.