Cardiovascular Disease

To Treat or Not To Treat? The New Cholesterol Guidelines

Slide05You may not realize this, but every time you go to the doctor and get your blood drawn for a cholesterol check, your physician is relying on established guidelines published in 2001 by the The Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program.  These guidelines, which were updated slightly in 2004, were based on trial evidence indicating that individuals with the lowest levels of low-density lipoprotein cholesterol (LDL-C, or bad cholesterol) also experience the lowest risk of coronary heart disease (CHD) and cardiac events. In other words, there appears to be a linear relationship between LDL-C and heart disease risk, as shown in the included graph. The lower the LDL-C, the better.

Slide10The ATP III guidelines have provided a rather simple numerical guide for clinicians to follow when deciding whether to treat an individual for hypercholesterolemia (high cholesterol).  Patients with more than 2 cardiovascular risk factors but not established CHD, for example, should strive for an LDL-C below 130 mg/dL. If they don’t achieve this goal, there is clinical indication to treat them with a cholesterol-lowering drug (typically a statin like Crestor or Lipitor). These straightforward guidelines are depicted at right.

Recently, the American College of Cardiology and American Heart Association shook up the world of cardiology and primary care by releasing new guidelines that dramatically differ from this established, quantitative rubric.  Slide20In essence, the working group of physicians who authored the new guidelines shifted the emphasis AWAY from relying on target numbers to diagnose and treat hypercholesterolemia.  Rather, they emphasized that the empirical evidence from our gold standard clinical trials (randomized, double-blind trials) supports treatment with statin therapy in 4 groups of people: 1) Patients with established atherosclerotic vascular disease (ASCVD), 2) Patients with LDL-C > 190 mg/dL, 3) Patients 40-75 years of age with diabetes, and 4) Individuals without clinical disease or diabetes but with a 10-year calculated ASCVD risk of 7.5% or higher.  A few other considerations (like family history, genetic hyperlipidemia, or an elevated coronary calcium score) might also support initiating statin therapy (a summary of new treatment guidelines are on right).

Authors of these new guidelines emphasized that there is no current evidence that hitting specific cholesterol targets (i.e., reducing cholesterol to a numerical LDL-C target like 100 or 130 mg/dL) systematically reduces atherosclerotic disease risk. This is certainly a controversial point of view, and means that certain patients who were being treated on the basis of high LDL-C alone may no longer be indicated for statin therapy.  By contrast, because the new guidelines calculate pooled ASCVD disease risk by taking into account factors such as stroke risk, age, and ethnicity, more women, African Americans and older adults than ever before will now fall into the “need-to-treat” category.
Slide26These guidelines continue to generate debate, and physicians have expressed a range of opinions about their clinical utility.  One last (and overlooked) point the authors made, however, is that diet and exercise should remain the foundation of any treatment regimen for cardiovascular disease. This is particularly valuable in light of a recent meta-analysis showing that exercise is as effective as drug interventions for preventing diabetes and coronary heart disease, and may be more effective than pharmacological treatment in stroke patients.  Unfortunately, the Rx for exercise isn’t quite as easy for people to fill.
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