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.
A microsimulation model-based analyses suggests that the health benefits associated with the 10-year atherosclerotic cardiovascular disease risk threshold of 7.5 percent or higher used in the 2013 ACC-AHA cholesterol guidelines are worth the additional costs required to achieve these health gains, and that a more lenient threshold might also be cost-effective, according to a study in the July 14 issue of JAMA.
In November 2013 the American College of Cardiology and the American Heart Association (ACC/AHA) released new recommendations to guide statin treatment initiation for the primary prevention of cardiovascular disease. These guidelines established 4 categories for statin treatment eligibility for adults 40 to 75 years of age, including 10-year atherosclerotic cardiovascular disease (ASCVD) risk of 7.5 percent or higher. It has been estimated that based on the new ASCVD risk threshold that 8.2 million additional adults in the U.S. would be recommended for statin treatment compared with previous recommendations. This expansion of statin treatment eligibility has been controversial, with some critics arguing that the guidelines substantially overestimate risk, and when taken in conjunction with more lenient treatment thresholds, millions of adults in the U.S. would be exposed to unnecessary statin treatment costs and risks, according to background information in the article.
Ankur Pandya, Ph.D., of the Harvard T.H. Chan School of Public Health, Boston, and colleagues performed a cost-effectiveness analysis of the ACC/AHA cholesterol treatment guidelines. With use of a microsimulation model, hypothetical individuals from a representative U.S. population 40 to 75 years of age received statin treatment, experienced ASCVD events, and died from ASCVD-related or non-ASCVD-related causes based on ASCVD natural history and statin treatment parameters. Data sources for model parameters included National Health and Nutrition Examination Surveys, large clinical trials and meta-analyses for statin benefits and treatment, and other published sources.
The researchers found that the current ASCVD threshold of 7.5 percent or higher, which was estimated to be associated with 48 percent of adults treated with statins, had an incremental cost-effectiveness ratio (ICER) of $37,000/quality-adjusted life-year (QALY) compared with a 10 percent or higher threshold. More lenient ASCVD thresholds of 4.0 percent or higher (61 percent of adults treated) and 3.0 percent or higher (67 percent of adults treated) had ICERs of $81,000/QALY and $140,000/QALY, respectively.
Shifting from the 7.5 percent or higher threshold to 3.0 percent or higher to 4.0 percent or higher was associated with an estimated additional 125,000 to 160,000 CVD events averted.
The optimal ASCVD threshold was sensitive to patient preferences for taking a pill daily, changes to statin price, and the risk of statin-induced diabetes.
"The decision to initiate statin treatment for adults without CVD should ultimately be informed by both evidence-based policies and patient preferences," the authors write.
"Based on available evidence, including the 2 reports in this issue of JAMA, answers to the questions of in whom and how regarding cholesterol lowering are now more clear than they were just 18 months ago," write Philip Greenland, M.D., of the Northwestern University Feinberg School of Medicine, Chicago, and Senior Editor, JAMA, and Michael S. Lauer, M.D., of the National Heart, Lung, and Blood Institute, Bethesda, Md., in an accompanying editorial.
"Available evidence indicates that statins are both effective and cost-effective for primary prevention even among low-risk individuals. Although lifestyle interventions must be employed across all segments of the population, for many people a statin drug will also be required to minimize risk. Where to set the treatment threshold and how to determine the individual's level of risk are also becoming progressively clarified."
"There is no longer any question as to whether to offer treatment with statins for patients for primary prevention, and there should now be fewer questions about how to treat and in whom. Rather, the next phase of research should be directed at better ways of applying lifestyle and drug treatments to the millions, and possibly billions, worldwide who could potentially benefit from a cost-effective approach to primary prevention of ASCVD."
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