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Skimming the Fat: A New Paradigm for Lipid Management—Commentary

10/05/15 Craig Alpert, MD, Cardiology Fellow, University of Michigan Health Systems; and Michael J. Shea, MD, Professor of Internal Medicine, Section Head, Cardiovascular Medicine Outpatient Services and Clinical Evaluation, University of Michigan Health Systems

In 2013, the world of preventive medicine was turned on its head. New cholesterol management guidelines, published jointly by the American College of Cardiology (ACC) and the American Heart Association (AHA), dealt a possibly fatal blow to the long-established thinking about high cholesterol levels and greatly increased the number of people for whom cholesterol treatment is recommended. Their controversial recommendations have been tested in a scientific study reported in this recent news article

Scientists and doctors have long known that high cholesterol levels increase the risk of heart attack and stroke. And they know that certain drugs and lifestyle changes that lower high cholesterol levels decrease that risk. However, doctors have long made certain assumptions. The first was that only people with high cholesterol levels need such treatment. The second was that “lower is always better” for cholesterol levels and thus certain target levels must be reached. 

There are two problems with these assumptions. First, some people have heart attacks and strokes without having high cholesterol levels. Second, some people have great difficulty meeting the old cholesterol target levels without taking several drugs, which exposes them to greater risk of side effects. Thus, doctors were not sure whether the increased risk of side effects paid off in decreased risk of heart attack and stroke. 

The recent ACC/AHA guidelines are the result of expert review of many studies on heart attack and stroke risk as well as cholesterol treatment.The new guidelines emphasize that the important thing is to prevent heart attack and stroke, not to achieve a certain blood level. The new guidelines have criteria besides cholesterol levels that identify people who are at risk and recommend that everyone whose risk is above a certain level should take the cholesterol-lowering drugs called statins whatever their cholesterol level. This evaluation method resulted in millions of new statin customers, drawing the ire of physicians and consumers alike. The AHA and ACC also found no evidence that people taking recommended treatments did any better if they struggled to lower their cholesterol levels to meet arbitrary targets. 

So are the new guidelines really better at identifying people at risk of cardiovascular disease? The study reported in this recent news article proposes an answer to this very question. The authors studied a group of 2,435 people who did not have known cardiovascular disease. They used both the old guidelines and the new guidelines to predict which people would develop such disease. Then they monitored these people for an average of over 9 years to see which ones actually developed heart attack or stroke. This way, they could see whether the old or the new guidelines were the best predictors. 

The results are quite staggering. The new guidelines are much better at predicting which people will have heart attack or stroke. And they are also better at predicting which people do not need statin therapy. Although the new ACC/AHA guidelines identified nearly three times as many people as potentially benefitting from statins, these new prescriptions appear justified because people who are identified do in fact have a higher risk of heart disease and strokes. Such people are in fact likely to benefit from treatment with statins.

See Dr. Shea's discussion of Biology of the Heart and Blood Vessels in the Merck Manual.