Accuracy of newer cholesterol guidelines in identifying increased risk of CVD events

(Press-News.org) An examination of the 2013 guidelines for determining statin eligibility, compared to guidelines from 2004, indicates that they are associated with greater accuracy and efficiency in identifying increased risk of cardiovascular disease (CVD) events and presence of subclinical coronary artery disease, particularly in individuals at intermediate risk, according to a study in the July 14 issue of JAMA.

The 2013 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the management of blood cholesterol represent a shift in the treatment approach for the primary prevention of CVD, from focusing on the treatment of traditional risk factors, including the management of low-density lipoprotein cholesterol levels, to absolute cardiovascular risk as estimated by the 10-year atherosclerotic CVD (ASCVD) score for statin treatment. It has been unclear whether this approach improves identification of adults at higher risk of cardiovascular events, according to background information in the article.

Udo Hoffmann, M.D., M.P.H., of Massachusetts General Hospital and Harvard Medical School, Boston, and colleagues conducted a study determine whether the ACC/AHA guidelines improve identification of individuals who develop incident CVD and/or have coronary artery calcification (CAC) compared with the National Cholesterol Education Program's Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III) guidelines. The study included participants from the offspring and third-generation cohorts of the Framingham Heart Study. Participants underwent multi-detector computed tomography for CAC between 2002 and 2005 and were followed up for a median of 9 years for new CVD.

The study population consisted of 2,435 participants not taking lipid-lowering therapy. The average age was 51 years; 56 percent were women. There were a total of 74 (3 percent) incident CVD events (40 nonfatal heart attacks, 31 nonfatal strokes, and 3 with fatal coronary heart disease [CHD]) and 43 (2 percent) incident CHD events (40 non­fatal heart attacks and 3 with fatal CHD).

The researchers found that overall, more participants were eligible for statin treatment when applying the 2013 ACC/AHA guidelines compared with the 2004 ATP III guidelines (39 percent vs 14 percent). Among those eligible for statin treatment by the ATP III guidelines, 7 percent developed incident CVD compared with 2 percent among noneligible participants. Applying the ACC/AHA guidelines, among those eligible for statin treatment, 6 percent developed incident CVD compared with only 1 percent among those not eligible. The hazard ratio (risk) of having incident CVD among statin-eligible vs noneligible participants was also higher when applying the ACC/AHA guidelines' statin eligibility criteria compared with the ATP III guidelines. "This finding is consistent across subgroups and particularly important in participants at intermediate CVD risk on the Framingham Risk Scores, the most challenging group in clinical practice for whom to decide to initiate statin therapy."

Participants with CAC were more likely to be statin eligible by ACC/AHA than by ATP III.

The authors write that extrapolating their findings to the approximately 10 million U.S. adults who are newly eligible for statins, an estimated 41,000 to 63,000 incident CVD events would be prevented over a 10-year period by adopting the ACC/AHA guidelines. They note that the absolute cardiovascular event risk of statin-noneligible adults is not much lower with the ACC/AHA guidelines (1 percent) compared with the ATP III guidelines (2.4 percent), and the larger benefit may be that the ACC/AHA guidelines identify many more statin-eligible participants with a similarly high event rate as the ATP III guidelines (6.3 percent vs 6.9 percent).

The researchers add that a risk-benefit analysis considering costs and potential adverse effects of statins, especially in patients with prediabetes and in lower-risk patients, is needed to provide a complete assessment of the effects of the change in statin eligibility guidelines on the health care system.

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(doi:10.1001/jama.2015.7515; Available pre-embargo to the media at http://media.jamanetwork.com)