Two leading heart organizations have released a new guideline for lifestyle changes and how best to use cholesterol-lowering drugs to prevent heart attacks and stroke.

The change is designed to address the rising rate of cardiovascular disease—the leading cause of death in the United States—by identifying groups that would benefit most from statins, a class of drugs that includes Pfizer's Lipitor and AstraZeneca's Crestor.

“The new guideline uses the highest quality scientific evidence to focus treatment of blood cholesterol on those likely to benefit most,” said Neil J. Stone, M.D., chair of the expert panel, in a statement on the American Heart Association website.

Released on Tuesday by the American Heart Association and the American College of Cardiology, the new guideline could alter how doctors prescribe statins. Overall, the changes should not increase the number of Americans taking these cholesterol-lowering drugs.

If the previous guideline had been followed, said Dr. Stone in an email to Healthline, about 16 percent of Americans would have been prescribed statins. However, the drugs were so popular that the actual use was much higher, around 30 percent. This is similar to what is estimated by the new guideline, if they are followed as laid out. 

“We likely are not increasing the number taking statins,” said Dr. Stone. “We are simply making sure that those who benefit will be taking them.”

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High-Risk Groups Identified

For many years, statins have played an important role in lowering levels of “bad” (LDL) cholesterol. The panel of experts that drafted the guideline chose to focus on statins because they have shown the most benefits for heart healthwith the fewest side effects.

Previously, people took these drugs with the aim of lowering their LDL cholesterol to certain target levels—less than 100 mg/dL or the optional goal of less than 70 mg/dL—monitored by regular blood tests. In some cases, people who did not reach these targets were prescribed other cholesterol-lowering drugs, as well.

While the definition of the optimal LDL level remains in place, doctors are no longer encouraged to prescribe statins based solely on reaching the target level. Now, experts advise that people remain on statins as long as they fall into a high-risk group, with no need for repeated blood tests.

The four groups that could benefit most from statins, as identified by the guideline, are: people with existing heart disease, people with an LDL level of 190 mg/dL or higher, people between 40 and 75 years of age who have type 2 diabetes, and people between 40 and 75 years of age who have a 10-year risk of heart disease that is 7.5 percent or higher.

The guideline provides formulas to help doctors calculate a person’s disease risk, taking into account many factors, including previous strokes and heart attacks. This is a departure from the existing standard of care, which focused mainly on lowering LDL cholesterol levels to a specific target.

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Lifestyle Changes Can Lower Cholesterol

According to the Centers for Disease Control and Prevention, heart disease kills about 600,000 people in the United States each year, accounting for 1 in 4 deaths. In addition, each year more than 795,000 Americans have a stroke, and nearly 130,000 die. A high LDL cholesterol level is a risk factor for both diseases.

In the new guideline, though, doctors are no longer encouraged to prescribe other cholesterol-lowering drugs that work differently from statins—including Merck’s Vytorin and Zetia. These drugs do lower cholesterol levels, but there is no evidence that they reduce the risk of heart attack or stroke enough, in light of their potential side effects, according to the panel.

In addition, “as low as possible” dosing of statins is no longer recommended. This practice involved prescribing a low dose of statins along with other cholesterol-lowering drugs. Instead, doctors are encouraged to prescribe moderate or high doses of statins, along with healthy lifestyle changes. People who experience bad side effects from statins, however, may still be prescribed other cholesterol-lowering drugs.

While the main focus of the new guideline is on defining who should receive statin drugs, it also emphasizes the importance of lifestyle changes in reducing cholesterol. This includes following a heart-healthy diet, exercising regularly, avoiding tobacco products, and maintaining a healthy weight.

“The focus for years has been on getting the LDL low,” said Stone. “Our guidelines are not against that. We’re simply saying how you get the LDL low is important. Considering all the possible treatments, we recommend a heart-healthy lifestyle and statin therapy for the best chance of reducing your risk of stroke or heart attack in the next 10 years.”

Correction: A previous version of this story incorrectly stated that the new cholesterol guideline could double the number of Americans taking statin drugs. In fact, under the new guidelines, about the same number of individuals will likely be on statins.