A daily low dose of aspirin can offer important protection against cardiovascular disease, but University of Florida researchers say that the people who could receive the most benefit from the medication may not be taking it.

A UF study found that only 40 percent of people who were at high risk of cardiovascular disease said they received a doctor recommendation for aspirin therapy, while one-quarter of people at low risk reported their doctors told them to take the drug.

The results appear in the Journal of the American Heart Association.

The U.S. Preventive Services Task Force, a panel of national experts in prevention and evidence-based medicine, recommends aspirin use to prevent heart attack and stroke in men age 45 to 79 and women age 55 to 79 when the benefit outweighs the risk of gastrointestinal bleeding, a possible side effect of regular aspirin use.

"Cardiovascular disease is a significant problem in the United States and the appropriate use of prevention strategies is particularly important," said Arch G. Mainous III, Ph.D., the study's lead investigator and chairman of the department of health services research, management and policy at UF's College of Public Health and Health Professions. "Aspirin has been advocated as a prevention strategy but only for certain patients. There are health risks associated with the treatment. It is important that doctors are directing the right patients to get aspirin for cardiovascular disease prevention."

Other studies have examined whether people at risk of heart attack or stroke were taking aspirin, but the UF study is the first to explore whether a person had received a doctor's recommendation for aspirin.

For the study, UF researchers analyzed data from the National Health and Nutrition Examination Survey 2011-2012, a large, nationally representative survey that combines survey questions with laboratory testing. About 3,500 participants over age 40 were asked if their doctor had recommended they take low-dose aspirin for the prevention of cardiovascular disease, stroke or cancer. If they had received the recommendation, participants were also asked if they were following their doctor's advice.

The UF team compared individuals' survey responses to their Framingham Risk Score, a risk assessment tool for determining a person's 10-year risk of having a heart attack. The tool calculates a score based on a person's age, gender, total and HDL cholesterol, smoking status and blood pressure. Researchers classified people who had a 10-year risk score of more than 10 percent as high risk, while patients with less than a 10 percent risk were classified as low risk.

"The results indicated that more than half of the patients who should have been recommended to take aspirin did not report being told by their health care provider to take aspirin," said Mainous, the Florida Blue endowed chair of health administration. "Further, a substantial proportion of those not at increased risk for cardiovascular disease were recommended to take aspirin.

"The vast majority of patients who reported being told to take aspirin were complying with their doctor's advice. The issue that was concerning to us wasn't adherence to treatment, but whether the right patients were being given advice on aspirin treatment appropriate for them."

Future research should evaluate whether making Framingham Risk Score computations available through electronic medical records would aid doctors in making accurate decisions about who should take low-dose aspirin, Mainous said.