In the News
Four new guidelines on the assessment and management of cardiovascular risk factors released by the American Heart Association (AHA) and American College of Cardiology (ACC) differ in several respects from previous guidelines and could lead to major changes in clinical practice. Unlike earlier guidelines, the new cardiovascular risk assessment guideline focuses on estimating a person's risk for stroke as well as heart attack and, for the first time, provides estimates applicable to black patients. No sooner were the guidelines released, however, than controversy arose, especially about the risk calculator accompanying the guidelines. (Links to all of the new guidelines can be found at http://bit.ly/1ju0yrv.)
The risk assessment guideline describes the use of race- and sex-specific pooled cohort equations to predict a patient's 10-year risk of a first “hard” atherosclerotic cardiovascular disease (ASCVD) event, defined as the first occurrence of nonfatal myocardial infarction or coronary heart disease death or a fatal or nonfatal stroke, in non-Hispanic black and non-Hispanic white men and women 40 to 79 years of age. Estimates are based on age, sex, race, total cholesterol level, high-density lipoprotein (HDL) cholesterol level, systolic blood pressure, use of antihypertensives, diabetes status, and smoking status. A downloadable spreadsheet and online risk calculator are provided for physicians and patients.
Critics contend, however, that the calculator could overestimate risk by 75% to 150% and greatly increase the number of patients for whom statin therapy is deemed appropriate. They urge that implementation be delayed until this “miscalibration” is addressed. The AHA and ACC were quick to defend the guidelines, pointing out that the risk calculator is meant to be only a starting point for discussion between patients and clinicians.
Elizabeth Bridges, associate professor and clinical researcher in the Department of Biobehavioral Nursing and Health Systems at the University of Washington, Seattle, agreed. “Do the guidelines mean that all at-risk individuals should be started on a statin? No.” In adults who don't have clinical ASCVD but are at risk for it, she said, the guidelines recommend primary prevention, including a discussion of the risks and benefits of drug therapy, as well as clinician and patient preferences. “In addition,” she said, “a healthy diet and lifestyle modifications remain central to prevention.”
A blood cholesterol–treatment guideline identifies four groups most likely to benefit from statin treatment and makes recommendations about the use of high- and moderate-intensity statin therapy for primary and secondary prevention. Unlike previous guidelines, it doesn't set specific low-density lipoprotein (LDL) cholesterol or non-HDL cholesterol targets. As Bridges explained, in patients with ASCVD statin therapy should be individualized in an attempt to decrease the patient's LDL cholesterol level by 30% to 50%, rather than to achieve a level under 100 mg/dL.
According to the risk assessment guideline, in patients 20 to 79 years old who don't have clinical ASCVD and whose 10-year risk is lower than 7.5%, risk factors should be assessed every four to six years. And according to the cholesterol treatment guideline, moderate- or high-intensity statin therapy should be considered in four other groups: patients 40 to 75 years old whose 10-year risk is 7.5% or higher, patients with clinical ASCVD, patients whose LDL cholesterol levels are 190 mg/dL or higher, and patients 40 to 75 years old with diabetes.
The third guideline provides detailed evaluations of dietary and physical activity recommendations to reduce ASCVD risk; the fourth provides guidance on the management of overweight and obesity in adults.—Karen Rosenberg