Coronary calcium screening influences use of statins and aspirin

Screening for coronary calcium may provide an impetus for physicians to initiate preventive cardiovascular therapies in patients who have coronary calcium, but persistence with the medications is no better than in patients who are started on therapies without a coronary calcium test, said Allen J. Taylor, MD.

At present, the American Heart Association (AHA) and American College of Cardiology (ACC) consider screening for coronary artery calcium to be a reasonable test in patients with an intermediate risk of a cardiovascular event based on risk factor profiling.

As part of a population screening study, 1,640 men without known coronary heart disease (CHD) were screened for CHD risk factors and for coronary artery calcium using electron beam computed tomography. The patients were followed for up to 6 years via telephone interviews, during which subsequent "ever use" and "consistent use" of statins and aspirin were recorded.

Almost one-fourth (22.4%) of patients had coronary artery calcium detected at baseline. At study entry, these patients were twice as likely to be using either a statin or aspirin than those without coronary calcium on their baseline test (9.9% vs. 4.7%, respectively).

During follow-up, the use of statins and aspirin increased progressively in both groups, but by 6 years statin use was 3 times more likely in patients with versus those without coronary calcium (48.5% vs. 15.5%; P <.001), and aspirin use was almost twice as likely (53.0% vs. 32.3%; P <.01).

Statin use was related to the presence of coronary artery calcium. Compared with the patients without coronary artery calcium, the ever use of a statin was 2 times greater in the patients with coronary artery calcium who were not at their low-density lipoprotein (LDL) cholesterol National Cholesterol Education Program (NCEP) goal at baseline and more than 4 times greater among those with an LDL cholesterol level below their NCEP goal.

"Within the patient-physician interaction, there was a recognition of risk from a calcium score and that led to this 3-fold increase in either statin use or aspirin use over those without calcium independent of other risk factors, and led to more appropriate use of the medicines," said Dr. Taylor, chief of cardiology at Walter Reed Army Medical Center in Washington, D.C.

After controlling for NCEP recommendations on initiating statin therapy and behavioral, demographic, and psychological variables, persistence with a statin or aspirin was not related to coronary artery calcium. Even so, only 10% to 20% of patients with or without coronary calcium failed to stay on their statin or aspirin, said Dr. Taylor.

"This was a very persistent group," he said. "If anything, the clinicians may have been driving the persistence because if the patients didn't have calcium, they still had risk factors that required treatment with a statin. If they had calcium, it resulted in greater use."

These are the first data to demonstrate that coronary artery calcium screening can influence management decisions, he said. Based on the findings, he added, refinement of risk with a calcium score in intermediate-risk patients is appropriate.