COMMENTARY

Cardiovascular Risk and Cholesterol: Making Sense of the New Guidelines

Sandra Adamson Fryhofer, MD

Disclosures

February 07, 2014

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Hello. I'm Dr. Sandra Fryhofer. Welcome to Medicine Matters. The topic: highlights from the new Cardiovascular Disease Prevention Guidelines, put out by the American Heart Association (AHA) and the American College of Cardiology (ACC), copublished in the Journal of the American College of Cardiology[1] and Circulation[2]. Here's why it matters.

Heart disease is the leading killer of men and women in this country. That is why the details of this new prevention package addressing risk assessment, lipids, obesity, and lifestyle are so important.

One major change is a new and somewhat controversial cardiovascular risk calculator. Although some experts have criticized this new calculator, saying it could overpredict risk by as much as 75%-150%, the AHA and ACC still stand in support of this new tool.

It uses pooled cohort equations and incorporates age, sex, race, total and high-density lipoprotein cholesterol (HDL-C), systolic blood pressure, use of blood pressure-lowering medications, and smoking status. It applies to African American and non-Hispanic white men and women aged 40-79 years. The new guidelines say that patients with an estimated 10-year risk for cardiovascular disease of 7.5% or higher should be placed on moderate- to high-dose statin therapy.

The same-intensity statin recommendation also applies to patients with clinical cardiovascular disease, anyone with a low-density lipoprotein cholesterol (LDL-C) level of 190 mg/dL or higher, and all diabetics aged 40-75 years.

Another change is the emphasis on statin dose intensity, rather than specific LDL-C treatment goals. The authors say that using treatment targets could result in undertreatment with evidence-based statin therapy, or overtreatment with the addition of nonstatin drugs that have not been shown in randomized controlled trials (RCTs) to reduce cardiovascular events.

However, review of RCTs showed that most patients on high-intensity statin therapy do have LDL-C values under 100 mg/dL. High-intensity therapy reduces cardiac events more than moderate-intensity statin therapy. For greatest protection, those who need statin therapy should take doses at the maximum tolerated intensity that does not cause side effects.

There are 7 statins currently available. They differ in milligram dose potency. Table 5 in the guidelines classifies the different statins according to dose and intensity. This table also reveals that the best evidence from RCTs supports the use of simvastatin, atorvastatin, and rosuvastatin.

The guidelines apply to persons aged 40-79 years. No RCT primary prevention data were available for those under 40 years, and not enough data were available for those over 75 years.

Consider treatment on an individual basis for patients with LDL-C levels of 160 mg/dL or higher. The guidelines also identify 4 additional markers to consider:

  1. A family history of premature heart disease in a first-degree male relative under 55 years or first-degree female relative under 65 years;

  2. High-sensitivity C-reactive protein level of 2 mg/L or more;

  3. An ankle/brachial index less than 0.90; and

  4. A coronary artery calcium score of 300 Agatston units or higher, or in at least the 75th percentile of age, sex, and ethnicity.

Of these 4 markers, the evidence for coronary artery calcium scores is the strongest. Although obtaining calcium scores does involve radiation exposure, it can be a determining factor in helping to decide whether treatment is appropriate.

Here are some more practice pearls from the guidelines:

Lipid panel monitoring. After statin therapy is started, check lipid panels again in 4-12 weeks to determine patient adherence, but not a specific LDL-C goal. Then check every 3-12 months as clinically indicated. Both medication adherence and adherence to lifestyle regimens are important. Consider lowering the statin dose if 2 consecutive LDL-C values are less than 40 mg/dL. The guidelines also advise against high-dose (80 mg) simvastatin.

Liver tests. Do check baseline liver tests, specifically alanine aminotransferase (ALT), before starting therapy. But there is no recommendation for continued routine liver test monitoring. Recheck liver tests during therapy in patients with symptoms of liver toxicity, including unusual fatigue, weakness, loss of appetite, abdominal pain, dark-colored urine, or yellowing of the skin or sclera.

Creatine kinase. There is no need to routinely check creatine kinase (CK). Check CK levels only in those with or at increased risk for adverse muscle symptoms.

Statins and diabetes. Patients placed on statins should be monitored for new-onset diabetes, but even if they do develop diabetes, they should still continue taking statins. Statins are pregnancy category X, and women of childbearing age who take them should be using contraception and should not be nursing.

Check out the full guidelines. There are many helpful tables and algorithms. The level of supporting evidence is also made clear for each recommendation.

For Medicine Matters, I'm Sandra Fryhofer.

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