At first glance, you might think that the study released last week comparing the cholesterol-lowering drugs Lipitor and Pravachol--funded by Pravachol's maker--produced a surprise slam-dunk for Lipitor. After all, the trial of more than 4,000 patients showed that those who started taking Lipitor instead of Pravachol within a week or so after being hospitalized for a heart attack or unstable angina had a 16% lower rate of getting worse--dying, suffering a subsequent heart attack or stroke, or requiring bypass surgery. But the seemingly obvious conclusion is not necessarily the right one. Here's why.
Pravachol and Lipitor are both statins--a group of cholesterol-lowering drugs that are widely used in the treatment of heart disease. Doctors have long known that Lipitor lowers the level of LDL, the so-called bad cholesterol, more than Pravachol does. Both groups of patients in this study--to be published in the April 8 issue of the New England Journal of Medicine but released a few weeks early--had their LDL levels reduced below 100 mg/dL--the target currently recommended by the National Heart, Lung, and Blood Institute (NHLBI) for folks who have heart disease or diabetes. The Lipitor patients achieved an average LDL level of 62 mg/dL, compared with 95 mg/dL for the Pravachol group.
What experts take from this is not that Lipitor is superior but that the official LDL targets may not be low enough. "LDL lowering is the name of the game," says Dr. James Cleeman, coordinator of the National Cholesterol Education Program at the NHLBI. "I don't think you can conclude that one brand is better than the other." Cleeman's group, which sets U.S. guidelines, is preparing a scientific paper to explain how doctors can best use the latest results in their practice.
No one knows yet how low LDL levels should go. Most likely, there is a point of diminishing returns where going any lower isn't worth the effort or the risk of side effects. "I'm currently treating patients with heart disease at LDL goals of 70 mg/dL," says Dr. Robert Eckel, chair of the American Heart Association's Council on Nutrition, Physical Activity and Metabolism. He says that if he can do that with Pravachol, he uses Pravachol. If not, he uses one of the other five statins currently available--depending on his patient's condition and insurance requirements. It's also important to use the lowest dose possible to avoid complications like muscle pain and body aches.
The issue for doctors is not how heart patients get their LDL lowered but that they do it--and fast. The NEJM study showed that the benefits of aggressively lowering LDL cholesterol start appearing in the first month after a patient is hospitalized. That's a lot sooner than anyone expected and a powerful argument for pushing LDL levels as low as they can go.