More than 10 percent of patients are inappropriately taking aspirin for primary cardiovascular disease (CVD) prevention, according to a new study.

A sample of 254,339 patients were looked at from 119 cardiology practices in the U.S. by a team of researchers. The patients were all taking aspirin for CVD protection, though it wasn't necessary for all of them, reported Medscape

The researchers found that more than 72 percent of the patients had missing variables that should be present when using aspirin as a CVD preventative drug, reported Medscape. 

The study emphasizes the need for doctors prescribing aspirin, as well as those taking it over-the-counter, to calculate the underlying risk of taking the drug for CVD protection. 

"The most important message is to recognize that there are people [who take] aspirin believing that they are protecting themselves from having heart attacks when they are actually exposing themselves to the [bleeding] risks of taking aspirin and likely having no benefit at all," Dr. Francisco Lopez-Jimenez, from Mayo Clinic in Rochester, Minn., who was not involved with the study, told Medscape. 

He suggested that the American Heart Association pooled-cohort calculator be used to determine the risk for an individual person. The calculator allows health care providers and patients to estimate 10-year and lifetime risks for atherosclerotic cardiovascular disease by looking at age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, blood pressure lowering medication use, diabetes status, and smoking status.  

The study will be published in the Jan. 20 issue of the Journal of the American College of Cardiology.