New guidelines for prescribing cholesterol-lowering medications are efficient and cost-effective, according to two new studies. 

The new research, published in JAMA, examines the 2013 recommendation that people ages 40 to 75 with at least a 7.5 percent risk of having a heart attack or stroke over the next 10 years receive statin drugs.

"We decide to look at this, because we felt it would be great to provide some information on how the guidelines actually work when you look at the (previous) guidelines," said Dr. Udo Hoffmann, the senior author of one study from Massachusetts General Hospital and Harvard Medical School in Boston.

In addition to people with a 7.5 percent risk for heart attacks or strokes, the 2013 guidelines - issued by the American College of Cardiology and the American Heart Association - advise statins for people with cardiovascular disease, for diabetics between ages 40 and 75, and for adults with high levels of “bad” low-density lipoprotein cholesterol.

Hoffmann and his colleagues say the new guidelines would result in 12.8 million more Americans being treated with statins, which include, for example, Lipitor (atorvastatin), Crestor (rosuvastatin) and Zocor (simvastatin).

The researchers looked at 10 years of data on nearly 2,500 people who were not taking statins. Under the new guidelines, 39 percent would have been eligible for statin therapy, compared to 14 percent under the old guidelines.

During the course of the study, 74 patients, or 3 percent, had cardiovascular events, including heart attacks and strokes.

When the researchers looked more closely, they found that cardiovascular events had occurred significantly more often in patients who would have been advised to take statins under the new guidelines.

Specifically, the rate of heart attacks and strokes was 6.3 percent in the group that would have been candidates for statin treatment, compared to 1 percent among patients who wouldn't be statin candidates under the new guidelines.

The researchers say their findings show the new guidelines were more accurate and efficient at identifying people with an increased risk of cardiovascular disease.

Applying their results to the U.S. population, the researchers estimate that between 41,000 and 63,000 cardiovascular events would be prevented over 10 years if the new guidelines were followed.

Hoffmann cautioned that the new results are based on a predominately white population. The risk calculator (bit.ly/1IWATG5) used for the new guideline considers race and ethnicity, he said.

Previously, experts have criticized the risk calculator for overestimating people's risk for heart disease (see Reuters story of March 19, 2014 here: reut.rs/QFtJxR.)

In a second study, also published in JAMA, researchers from the Harvard School of Public Health in Boston also found the new guidelines were cost effective.

Using a computer simulation, Ankur Pandya and colleagues found the 7.5 percent risk threshold over 10 years would cost about $37,000 per quality-adjusted-life-year (QALY) gained.

A QALY is a standard measure of how much a treatment or intervention costs to earn one year of healthy life. In general, policymakers historically view interventions costing less than $50,000 per QALY as cost effective.

The researchers said risk thresholds lower than 7.5 percent would be acceptable if interventions costing $100,000 or $150,000 were considered cost effective.

"We found that 7.5 percent number is actually pretty good when it comes to value and you can actually push it a little further on cost effectiveness grounds," lead author Pandya told Reuters Health.

Based on existing evidence and the new reports, Dr. Phillip Greenland of the Northwestern University Feinberg School of Medicine in Chicago and Dr. Michael Lauer of National Heart, Lung and Blood Institute in Bethesda, Maryland, call the 7.5 percent threshold justified and possibly too conservative.

"There is no longer any question as to whether to offer treatment with statins for patients for primary prevention, and there should now be fewer questions about how to treat and in whom," they write in an editorial.

Statins come with the potential for side effects, including muscle and stomach discomfort. But research suggests those can be overcome without lasting problems.