New Cholesterol Study Answers Some Questions, but Raises Others

By MARC SIEGEL, M.D.

When prescribing any drug, a discerning physician must respond to the patient’s individual situation and the evolution of facts on the drug and not just interpret the results of a single study.

Cholesterol drugs are an important example. A recent, widely publicized study at the Cleveland Clinic compared high doses of one cholesterol-lowering drug, Lipitor, with another, Pravachol, administered at lower doses. The study seemed to show that Lipitor does more to slow the progression of heart disease.

But this study does not translate into a black-and-white prescribing decision for doctors. Previous studies have shown that Pravachol and other drugs known as statins — drugs that slow the liver’s production of cholesterol — also reduce the risk of heart attacks, strokes, and associated deaths. Studies must be integrated with clinical experience, and a comprehensive treatment plan developed.

“If you manage to get to target, stay on the drug that’s doing it for you,” advises Dr. Howard Weintraub, clinical co-director of the lipid treatment and research center at NYU.

But what is an appropriate target? Dr. Weintraub is among many cardiologists who believe in using a patient’s risk factors for heart disease to determine a target number for cholesterol. Low Density Lipoprotein, known as “bad” cholesterol, is the gold standard by which cardiologists assess cardiac risk. Dr. Weintraub and others also routinely assess cardiac risk factors such as obesity, sedentary lifestyle, male gender, smoking, and family history of heart disease.

The current national guidelines would suggest that an LDL of less than 130 is sufficient for patients without demonstrable heart disease, and less than 100 for those with heart disease. But Dr. Weintraub doesn’t think these guidelines are sufficient. For one thing, the Cleveland Clinic and other studies show that coronary disease may progress in patients with an LDL between 70 and 100. Further, previous investigations show that people with cardiac risk factors may begin to develop diseased coronaries at a very early age.

It is difficult to determine the rate at which clogged arteries translate into angina and heart attacks. What is already proven, however, is that treating the “walking time bombs” among us cuts down on illness. A 2001 trial known as Air Force Texas Coronary Artery Prevention Study showed a 40% reduction of cardiac events in over 6,000 high-risk patients who were treated with Lipitor.

Dr. Weintraub says, “The mistake doctors make is to send patients for stress tests and then tell them everything is okay. But it isn’t always the case. You have to look at the patient, the age, gender, family history, diet. I am convinced that there is an important distinction between an LDL of 100 and 70. A single drug strategy that lowers cholesterol more aggressively would be more beneficial in highrisk groups.”

What is a doctor to do when a cholesterol-lowering drug is only partially effective but the patient is tolerating it? Currently, the answer isn’t known. A growing body of evidence would suggest that a complementary drug such as Zetia should be added, or alternatively, a switch to a more potent statin such as Lipitor or the newly released Crestor. If a patient doesn’t tolerate the change, you can always switch back and move to a higher dose of the original drug.

Meanwhile, more studies are in the offing looking to correlate cholesterol reduction with decreases in heart attacks and strokes. Many physicians welcome head-to-head trials between drugs, not only to help choose between them, but also to help determine an accurate endpoint to treatment.

With cholesterol lowering as well as with any other medical intervention, we look for a standard of medical practice that we can apply from patient to patient. At the same time, clinical judgment, with variations from patient to patient, continues to play a crucial role.

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Copyright © 1990-2007 Marc K. Siegel, M.D.