Absence of Coronary Calcium Reclassifies Nearly 50% of Statin-Eligible Patients: MESA Analysis
October 06, 2015
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MIAMI, FL — Two new analyses of the Multi-Ethnic Study of Atherosclerosis (MESA) provide evidence that the use of coronary artery calcium (CAC) screening can reclassify patients at risk from cardiovascular disease and better identify those who would most benefit from statin therapy compared with current guidelines.
In the first study[1], which was led by Dr Khurram Nasir (Baptist Health South Florida, Miami), investigators found that 50% of 4758 MESA participants would be recommended for moderate- or high-intensity statin therapy based on the 2013 American College of Cardiology/American Heart Association (ACC/AHA) clinical guidelines. Moreover, another 12% of patients could be “considered” for statin therapy based on their 10-year 5% to 7.5% risk of atherosclerotic cardiovascular disease (ASCVD).
Taken together, the researchers say that nearly two-thirds (62%) of the MESA cohort would be recommended or considered for statin therapy.
Yet among those recommended statins—this included patients with an LDL-cholesterol level >190 mg/dL, diabetic patients with an LDL-cholesterol level 70–189 mg/dL, and nondiabetic patients with an LDL-cholesterol level 70–189 mg/dL and an estimated 10-year ASCVD risk >7.5%—more than 40% of these individuals had a CAC score of zero and an ASCVD event rate of 5.2 per 1000 person-years of follow-up. Among those who could be considered for statin therapy, 57% of these individuals had a CAC score of zero and an ASCVD event rate of 1.5 per 1000 person-years of follow-up.
Of the entire group eligible for statins, either recommended or considered, 44% of the 2966 patients had a CAC score of zero at baseline and a 10-year ASCVD event rate of 4.2 per 1000 person-years.
“Overall, our results showed that nearly 50% of individuals who are statin candidates, if they undergo a test that costs between $75 and $100, would have a calcium score of zero, and their 10-year risk would be below the threshold in which the guidelines recommend statins,” Nasir told heartwire from Medscape. “This is most important for the patients in the middle, those who have a 10-year risk of 5% to 20%.”
In contrast, 56% of patients considered statin eligible based on the guidelines had coronary calcification identified on the noncontrast computed tomography (CT) scan (CAC>0) and had an ASCVD event rate of 11.2 events per 1000 person-years.
The results of the study, along with another analysis led by Dr Robyn McClelland (University of Washington, Seattle) that included CAC scores in a risk-prediction algorithm, are published in the October 13, 2015 issue of the Journal of the American College of Cardiology.
Deep Dive Into the Benefits of Adding CAC
Speaking with heartwire , Nasir said the recent change in statin guidelines—one that moved away from LDL-cholesterol targets to focus on risk—expanded the number of eligible patients. In their analysis, of the 2377 MESA participants who are candidates for statin therapy, 77% would be recommended the drugs because their 10-year risk of ASCVD was 7.5% or greater. While he said the focus on patient risk is commendable, statins, despite being cost-effective and safe, are a lifelong therapy for patients.