The American Heart Association’s 2013 recommendation for expanded statin use has raised eyebrows over whether the medications are now prescribed too much. But researchers at Washington University have found that analyzing genetics may help doctors determine who is most likely to benefit from the cholesterol-lowering therapy. 

For their study, published Wednesday in The Lancet, scientists used statistical methods to examine heart attack risk among a total of 49,000 people enrolled in five studies. Researchers adjusted for traditional heart disease factors like age, sex, cholesterol levels, smoking history and diabetes diagnosis to designate the group of individuals deemed at a high risk for having a heart attack based solely on their genetics.

According to a news release, the high-risk group had a 70 percent greater chance of having a heart attack compared to those at the lowest genetic risk. And statins— which help improve cholesterol and thus lower the likelihood of having a heart attack— helped reduce that risk by 48 percent among the high genetic-risk group, compared to a 29 percent reduced risk among the intermediate group and a 13 percent reduced risk among the low genetic-risk group.

“There is ongoing debate over which individuals should be allocated statin therapy to prevent a first heart attack,” study author Nathan O. Stitziel, a Washington University cardiologist and human geneticist, said in the news release. “Genetics appears to be one way to identify high-risk patients.”

In the news release, Stitziel said the findings are new because previous studies haven’t differentiated statin success among genetically different individuals. Prior research has indicated the same relative risk reduction, from 30 to 45 percent, across all categories of patients.

“We need more research to confirm these results,” Stitziel said. “Regardless, we can at least say that patients with a high genetic-risk score appear to benefit more from statin therapy because they’re starting at a higher baseline risk, even controlling for all the clinical measures we routinely examine.”

Study authors analyzed 27 individual components of each patient’s DNA code to calculate their genetic-risk score. Previous research suggests these 27 immutable “letters” are linked to coronary heart disease, and that locations hold different weight with respect to risk.

Researchers also calculated the number of patients that doctors would need to treat with statins to prevent one heart attack over a 10-year period, and they observed that the high genetic-risk group saw the biggest benefit from statin use, according to the news release.

Among the low genetic-risk group, doctors would need to treat 57 to 66 patients for 10 years to prevent a heart attack, while only 20 to 25 high genetic-risk patients would need to take a statin for 10 years to prevent one individual’s heart attack.

Stitiziel said further research needs to be done to determine whether a genetic-risk analysis may be an effective tool to determine whether statins are appropriate for a given patient. But he added that because DNA don’t change, the test has the potential to detect heart attack risk even before traditional measures such as blood work.

According to the Centers for Disease Control and Prevention (CDC), the percentage of adults aged 40 and older using cholesterol-lowering medication rose from 20 percent to 28 percent between 2003 and 2012. Statin use climbed from 19 to 26 percent during that period, and from 2011 to 2012, about 93 percent of adults using a medication to combat high cholesterol reported using a statin.

The American Heart Association and the American College of Cardiology said in 2013 that statins could be prescribed to an estimated 33 million Americans without heart disease who  have at least a 7.5 percent risk for heart attack or stroke within the next 10 years. In 2002, federal cholesterol guidelines recommended that people take a statin only if their 10-year risk level surpassed 20 percent— a suggestion based only on heart disease risk, not stroke.