The new cardiovascular disease prevention guidelines: What you need to know
A new, partially tested CVD risk-assessment tool significantly increases the number of individuals who would qualify for statin therapy. Treating to a target LDL-C value has given way to reducing the level by different percentages based on patient characteristics.
Summary highlights:
• Use race- and sex-specific Pooled Cohort Equations to predict 10-year risk for a first hard ASCVD event (nonfatalmyocardial infarction, coronary death, or nonfatal or fatal stroke) in non-Hispanic African Americans and non-Hispanic Whites, 40 to 79 years of age.
• Consider assessing a patient’s family history, high-sensitivity C-reactive protein, coronary artery calcium, or anklebrachial index to help guide treatment decisions if quantitative risk assessment has led to uncertainty. (This recommendation is based on expert opinion.)
• Consider evaluating ASCVD risk factors every 4 to 6 years in individuals 20 to 79 years of age who do not have ASCVD, and calculating the 10-year risk of an ASCVD event in those 40 to 79 years of age.
• Consider evaluating 30-year or lifetime ASCVD risk using traditional risk factors in individuals 20 to 59 years of age who do not have ASCVD and have no high short-term risk. (This is based on low-level evidence.)
Cholesterol management
The guideline on lowering blood cholesterol4 is a significant departure from the previous one.6 It contains 54 recommendations, 21 based on expert opinion. Using an unusual methodology that considered only randomized controlled trials in the evidence report, the guideline panel stated that the evidence demonstrates that 4 groups will benefit from treatment with statins:
• patients with established ASCVD
• individuals whose LDL-C is ≥190 mg/dL
• patients with diabetes and no established ASCVD who are 40 to 75 years of age and have an LDL-C between 70 and 189 mg/dL
• anyone with an estimated 10-year ASCVD risk of ≥7.5% (based on the new risk-assessment tool) and an LDL-C of 70 to 189 mg/dL.
The major departure from the old guideline is an abandonment of “treating to target” that attempts to lower LDL-C to a specified level. The panel concluded that the evidence does not show any benefit in achieving a specified level of LDL-C and that this approach can lead to either over- or under-treatment. The proposed new approach is to use high-, moderate-, or low-intensity statin treatment based on a patient’s age and reason for treatment, and the dose that they can tolerate (TABLE 2).4
Absent any contraindications, high-intensity treatment is indicated for:
• patients ≤75 years old with established ASCVD
• patients with an LDL-C level ≥190mg/dL
• patients 40 to 75 years old with diabetes and a ≥7.5% 10-year risk of ASCVD. z
Moderate-intensity treatment is indicated for those who cannot tolerate a high-intensity regimen, and for those ages 40 to 75 with diabetes and <7.5% 10-year ASCVD risk.
Low-intensity treatment is recommended for those who should receive moderate-intensity treatment but cannot tolerate it.
For those >75 years of age, the guideline makes only 2 recommendations:
• Prescribe a statin at the highest tolerable intensity for an LDL-C ≥190mg/dL.
• Assess those with established ASCVD for potential benefits and risks of moderate to high-intensity statin treatment. (It is reasonable to continue statin therapy for those already on it and tolerating it.)
Value of nonstatin drugs is questionable. In another significant departure from the previous guideline, the panel said that other cholesterol-lowering drugs can be considered when LDL-C remains high after statin treatment, but the benefit of these agents in preventing ASCVD is not proven.
Several objections to the new guideline have been raised in the short time since its release. Criticisms center on the large number of adults who would now qualify for statin treatment based on the new risk-assessment tool. Using the 7.5% 10-year risk cutoff, the number needed to treat to prevent one ASCVD event over 10 years would be 67. Also of concern to many is the fact that 7 out of 16 members of the guideline panel had financial ties to the pharmaceutical industry.12
Commentary
The new guidelines reflect a more rigorous evidence-based approach than those of the past. That some of them diverge significantly from previous recommendations that relied heavily on expert opinion reveals the pitfalls of making authoritative recommendations based on weak evidence. Such recommendations, especially those emerging from the National Institutes of Health, are used as national and international standards and serve as the basis of performance measures. When they do not stand the test of time because of a weak evidence base, medicine’s reputation is damaged. Notably, the new set of cholesterol recommendations, while an improvement from an evidentiary perspective, is founded partly on a questionable risk-assessment tool, and it is possible it will suffer the same long-term fate as its predecessor. (For more on these guidelines, see “The new cholesterol guideline: Beyond the headlines,” [J Fam Pract. 2013;62:730.])
