Summary of Recommendations

Screening men: The U.S. Preventive Services Task Force (USPSTF) strongly recommends screening men 35 years and older for lipid disorders. A recommendation.

The USPSTF recommends screening men 20 to 35 years of age for lipid disorders if they are at increased risk of coronary heart disease (CHD). B recommendation.

Screening women at increased risk: The USPSTF strongly recommends screening women 45 years and older for lipid disorders if they are at increased risk of CHD. A recommendation.

The USPSTF recommends screening women 20 to 45 years of age for lipid disorders if they are at increased risk of CHD. B recommendation.

Screening young men and all women not at increased risk: The USPSTF makes no recommendation for or against routine screening for lipid disorders in men 20 to 35 years of age, or in women 20 years and older who are not at increased risk of CHD. C recommendation.

Rationale

Importance. There is good evidence that high levels of total cholesterol and low-density lipoprotein (LDL) cholesterol, and low levels of high-density lipoprotein (HDL) cholesterol are important risk factors for CHD. The risk of CHD is highest in persons with a combination of risk factors. The 10-year risk of CHD is lowest in young men and in women who do not have other risk factors, even in the presence of abnormal lipid levels.

Detection. The USPSTF found good evidence that lipid measurement can identify asymptomatic men and women who are eligible for preventive therapy.

Benefits of detection and early treatment. There is good evidence that lipid-lowering drug therapy substantially decreases the incidence of CHD in persons with abnormal lipid levels. The absolute benefits of lipid-lowering treatment depend on a person's underlying risk of CHD. Men older than 35 years and women older than 45 years who are at increased risk of CHD will realize a substantial benefit from treatment. Younger adults with multiple risk factors for CHD, including dyslipidemia, will realize a moderate benefit from treatment. Younger men and women without risk factors for CHD will realize a small benefit from treatment, as seen in the risk reduction in 10-year CHD event rate.

Harms of detection and early treatment. There is good evidence that the harms from screening and treatment are small, and include possible labeling and the adverse effects associated with lipid-lowering therapy (e.g., rhabdomyolysis).

USPSTF assessment. The USPSTF concludes that the benefits of screening for and treating lipid disorders in all men 35 years and older, and women 45 years and older at increased risk of CHD substantially outweigh the potential harms. The USPSTF concludes that the benefits of screening for and treating lipid disorders in young adults at increased risk of CHD moderately outweigh the potential harms.

The USPSTF concludes that the net benefits of screening for lipid disorders in young adults not at increased risk of CHD are not sufficient to make a general recommendation.

Clinical Considerations

• Lipid disorders, also called dyslipidemias, are abnormalities of lipoprotein metabolism and include elevations of total cholesterol, LDL cholesterol, or triglycerides; or deficiencies of HDL cholesterol. These disorders can be acquired or familial (e.g., familial hypercholesterolemia). This recommendation applies to adults 20 years and older who have not previously been diagnosed with dyslipidemia.

• Increased risk, for the purposes of this recommendation, is defined by the presence of any one of the risk factors listed. The greatest risk of CHD is conferred by a combination of multiple factors. Although the USPSTF did not use a specific numerical risk for this recommendation, the framework used by the USPSTF in making these recommendations relies on a 10-year risk of cardiovascular events¹:

• Diabetes

• Personal history of CHD or noncoronary atherosclerosis (e.g., abdominal aortic aneurysm, peripheral artery disease, carotid artery stenosis)

• Family history of cardiovascular disease before 50 years of age in male relatives or 60 years of age in female relatives

• Tobacco use

• Hypertension

• Obesity (body mass index of 30 kg per m² or greater)

• The preferred screening tests for dyslipidemia are total cholesterol and HDL cholesterol levels on nonfasting or fasting samples. There is currently insufficient evidence of the benefit of including triglycerides as a part of the initial tests used to screen routinely for dyslipidemia. Abnormal screening test results should be confirmed by a repeated sample on a separate occasion, and the average of both results should be used for risk assessment.

• Measuring total cholesterol alone is acceptable for screening if available laboratory services cannot provide reliable measurements of HDL cholesterol; measuring total cholesterol and HDL cholesterol is more sensitive and specific for assessing CHD risk than measuring total cholesterol alone. In conjunction with measuring HDL cholesterol, the addition of measuring LDL cholesterol or total cholesterol would provide comparable information, although measuring LDL cholesterol requires a fasting sample and is more expensive. Direct LDL cholesterol testing, which does not require a fasting sample measurement, is now available; however, calculated LDL cholesterol (total cholesterol minus HDL cholesterol minus triglycerides, divided by 5) is the validated measurement used in trials for risk assessment and treatment decisions. In patients with dyslipidemia identified by screening, complete lipoprotein analysis is useful.

• The optimal interval for screening is uncertain. On the basis of other guidelines and expert opinion, reasonable options include every five years; shorter intervals for persons who have lipid levels close to those warranting therapy; and longer intervals for those not at increased risk who have had repeatedly normal lipid levels.

• An age to stop screening has not been established. Screening may be appropriate in older persons who have never been screened; repeated screening is less important in older persons because lipid levels are less likely to increase after 65 years of age. However, because older adults have an increased baseline risk of CHD, they stand to gain greater absolute benefit from the treatment of dyslipidemia, compared with younger adults.

• Treatment decisions should take into account a person's overall risk of heart disease rather than lipid levels alone. Overall risk assessment should include the following factors: age, sex, diabetes, elevated blood pressure, family history (in younger adults), and smoking. Risk calculators that incorporate specific information on multiple risk factors provide a more accurate estimation of cardiovascular risk than tools that count numbers of risk factors.¹

• Drug therapy is usually more effective than diet alone in improving lipid profiles, but choice of treatment should consider overall risk, costs of treatment, and patient preferences. Guidelines for treating lipid disorders are available from the National Cholesterol Education Program of the National Institutes of Health (http://www.nhlbi.nih.gov/about/ncep/).

• Although lifestyle modifications (diet and physical activity) are appropriate initial therapies for most patients, a minority achieves substantial reductions in lipid levels from changes in diet alone; drugs are frequently needed to achieve therapeutic goals, especially for persons at increased risk of CHD. Lipid-lowering treatments should be accompanied by interventions addressing all modifiable risk factors for heart disease, including smoking cessation, treatment of blood pressure, diabetes, and obesity, as well as promotion of a healthy diet and regular physical activity. Long-term adherence to therapies should be emphasized.