A newly developed risk equation appeared to be a valid estimator of atherosclerotic cardiovascular disease risk among patients considered for statin initiation, according to research presented March 29 at the American College of Cardiology (ACC) scientific session in Washington, D.C. The results were simultaneously published online in JAMA.
ACC.14: ACC/AHA cardiovascular risk tool well calibrated
Paul Muntner, PhD, of the University of Alabama at Birmingham, and colleagues sought to validate the ACC/American Heart Association (AHA) Pooled Cohort risk equations using data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. REGARDS investigated higher stroke mortality among blacks and residents of the southeastern U.S. compared with whites and other parts of the country. REGARDS analyzed data from more than 18,000 adults aged 45 to 79 who had no history of coronary heart disease, stroke, heart failure or atrial fibrillation.
The Pooled Cohort risk equations were developed by the ACC/AHA to help predict 10-year atherosclerotic cardiovascular disease risk and were developed using several population cohorts. The 2013 ACC/AHA guidelines for treatment of cholesterol called for using the equations to estimate risk and determine whether to start statin therapy in certain adults.
In addition to analyzing REGARDS participants without atherosclerotic cardiovascular disease, the researchers did some analysis on participants to whom the risk equations would apply (those without clinical atherosclerotic cardiovascular disease or diabetes, with low-density lipoprotein cholesterol levels between 70 and 189 mg/dL and not taking statins).
As outcomes, they evaluated predicted risk and observed incidence of atherosclerotic cardiovascular disease, defined as nonfatal MI, coronary heart disease, nonfatal or fatal stroke at five years.
There were 338 events, and the observed and predicted five-year atherosclerotic cardiovascular disease (CVD) incidence per 1,000 person-years for those with a 10-year predicted atherosclerotic CVD risk of less than 5 percent was 1.9 and 1.9, risk of 5 percent to less than 7.5 percent was 4.8 and 4.8, risk of 7.5 percent to less than 10 percent was 6.1 and 6.9, and risk of 10 percent or greater was 12 and 15.1. The C index was 0.72.
Although the data suggest the Pooled Cohort risk equations were well calibrated, “counseling and treatment decisions should be individualized as suggested by the new cholesterol guidelines,” they wrote.