ACC.14: Cardiovascular disease guidelines may not be best risk estimators

Differences between cardiovascular disease prevention guidelines mean that different proportions of individuals would be eligible for statin therapy, according to results presented March 29 at the American College of Cardiology (ACC) scientific session in Washington, D.C. The results were simultaneously published online in JAMA.  Researchers led by Maryam Kavousi, MD, PhD, of Erasmus University Medical Center in Rotterdam, the Netherlands, compared guidelines issued by the ACC/American Heart Association (AHA), the National Cholesterol Education Program’s Adult Treatment Panel III (ATP-III) and the European Society of Cardiology (ESC) among a cohort of 4,854 Rotterdam Study participants who were recruited between 1997 and 2001. The Rotterdam Study is a prospective study of chronic disease among individuals 55 and older living in a Dutch suburb. Kavousi and colleagues calculated 10-year risk for “hard” atherosclerotic cardiovascular disease (ASCVD) events, which included fatal and nonfatal coronary heart disease and stroke (ACC/AHA guidelines); hard coronary heart disease (CHD) events, including fatal and nonfatal MI along with CHD mortality (ATP-III guidelines); and atherosclerotic mortality (ESC guidelines). Based on each set of guidelines, they calculated the proportions of participants who fit into the categories of “treatment recommended,” “treatment considered” and “no treatment.” Their analysis found statins would be recommended for 96.4 percent of men and 65.8 percent of women based on ACC/AHA guidelines. When considering ATP-III guidelines, 52 percent of men and 35.5 percent of women would be recommended for treatment; based on ESC guidelines, 66.1 percent of men and 39.1 percent of women would be treated. Average predicted risk vs. observed cumulative incidence of hard ASCVD events was 21.5 percent vs. 12.7 percent for men and 11.6 percent vs. 7.9 percent for women for the ACC/AHA guidelines. The ATP-III guidelines and the ESC guidelines also overestimated risk. The C statistic was 0.67 in men and 0.68 for women in hard ASCVD (ACC/AHA guidelines), 0.67 in men and 0.69 in women for hard CHD (ATP-III), and 0.76 in men and 0.77 in women for CVD mortality (ESC). Based on the differences in guidelines, the authors found ACC/AHA guidelines would recommend statins for almost all men and about 2/3 of women, higher proportions than suggested by the other guidelines. The guidelines also overestimated risk. “Given the modest discrimination and poor calibration of the ACC/AHA risk prediction model, the choice of treatment threshold becomes central,” they wrote.