Torrance, CA -"Show, don't tell" is what writers are told to do, but this same principle might also apply to doctors involved in disease prevention. The results of a new study suggest that patients who can see the buildup of plaque within their arteries are more likely to comply with medical therapy [1]. Rather than telling patients they are at risk for future cardiovascular events, visualization of coronary calcium appears to improve utilization and adherence to lipid-lowering therapy, say investigators.

"We found that adherence increased in the group who would most likely benefit from lipid-lowering therapy, those patients with increased levels of subclinical atherosclerosis," write Dr Nove Kalia (Harbor-University of California Los Angeles Medical Center, Torrance, CA) and colleagues in the April 2006 issue of Atherosclerosis. "Our results as well as the results of previous studies suggest that [coronary artery calcium] CAC found on [electron-beam tomography] EBT may add much-needed motivation to asymptomatic patients recommended for lifestyle modification and drug therapy."

As most clinicians are aware, despite the benefits of lipid-lowering drugs for primary and secondary prevention, the therapy remains underutilized. Long-term compliance is also poor in the primary-prevention cohort, as well as poor among those who have survived MI. Moreover, recent studies have shown that consistent use of evidence-based medicines is lowest among groups with the highest risk of poor outcomes and who would therefore benefit most from sustained therapy.

Kalia and colleagues evaluated patients who underwent EBT coronary-calcium measurements at least one year prior with a survey questioning them about their health behaviors. Patients with known cardiovascular disease were not included in the study. In total, the study population consisted of 505 individuals on statin therapy at baseline, a majority of whom were men. The patients were divided into quartiles based on CAC score and followed for an average of three years.

At follow-up, statin compliance was shown to increase with increasing CAC scores measured at baseline. Overall, statin compliance was lowest among those with CAC scores in the first quartile and highest among those in the fourth quartile.

Investigators also evaluated statin adherence in patients in each CAC quartile based on the presence or absence of cardiovascular risk factors. Similar adherence was observed irrespective of these risk factors. In addition, multivariable analysis adjusting for age, gender, hypertension, diabetes, tobacco use, and family history of cardiovascular disease showed that individuals in the fourth quartile, those with CAC scores >527, were nearly 10 times more likely to stick with statin therapy compared with those in the first quartile.

"It is possible that seeing the calcification changed their perception of their own health status," the authors suggest. In their paper, they note that the results contrast with the 2003 randomized controlled study by Dr Patrick O'Malley (Walter Reed Army Medical Center, Washington, DC) and colleagues showing that people privy to the results of their EBT tests are no more likely than people receiving standard risk-factor assessment to modify their risky habits over the following year [2].

The patient population in that trial was largely composed of military personnel at low risk for coronary disease. According to Kalia et al, the low prevalence of modifiable risk factors and low coronary calcium scores in the O'Malley cohort may have complicated efforts to show an effect of EBT tests on risk-factor modification.