CT Scans Outperform Polygenic Risk Prediction Methods for Heart Disease

Computed tomography (CT) scans for coronary artery calcium significantly improved risk predictions for heart disease in middle-aged patients compared to polygenic risk scores, according to a study published last week in JAMA.

Conventional risk factors for heart disease, such as cholesterol and blood pressure levels, are typically used to gauge an individual's likelihood of developing artery blockages or other heart-related conditions. However, the study indicates that some patients may experience heart problems, like a heart attack, without demonstrating increased risk based on these factors.

Many of these patients have been found to inherit their heart disease risk, which has led researchers to propose the use of genetic data to help determine patient risk through polygenic risk scores, according to a news release published alongside the study. However, the study states that coronary artery calcium score, which is determined using CT scans, may also serve as an accurate indicator of coronary heart disease (CHD).

The researchers set out to evaluate whether a coronary artery calcium score or a polygenic risk score would improve risk discrimination when added to a CHD model based on conventional risk factors.

To do so, the research team pulled data from two population-based studies, which were comprised of 3,208 adults of European ancestry aged 45 to 79 years deemed free of CHD at baseline.

Patient data related to CHD risk factors, including blood pressure, smoking status, and cholesterol levels for up to 17 years of patient follow-up were used to stratify patient risk. From there, the researchers combined these data with CT scans and genetic information to see how these additional factors would impact CHD risk.

The research team found that genetic data did not affect individuals’ risk categories based on conventional factors. Conversely, when CT scans were incorporated, approximately half of the study cohort moved from a lower-risk group to a higher one.

Individuals with less than a 7.5 percent risk of developing heart disease in the next ten years are considered low risk, whereas those whose risk is higher than 7.5 percent transition into the high-risk group. For these patients, statins are typically recommended to manage their heart disease risk.

“Finding the best way to identify who is at risk for developing heart disease can help determine what needs to be done to lower their risk,” said lead study author Sadiya Khan, MD, assistant professor of Medicine in the Division of Cardiology and of Preventive Medicine at Northwestern University Feinberg School of Medicine, in the release. “This finding can help doctors and patients in managing risk for heart disease, which is the leading cause of death in the [United States].”

The study’s findings also support recommendations to use CT scans when calculating heart disease risk for middle-aged patients with an uncertain or intermediate degree of risk based on conventional factors, the researchers indicated.