What does the new cardiovascular risk calculator mean for patients?

The analysis, published on July 29, JAMAestimates that the new risk calculator will make about 16 million people newly ineligible under current standards of care that guide clinical decisions about who should take cholesterol and blood pressure medications. The change in treatment eligibility will be most pronounced among men ages 50 to 69. As a result, access to statins and blood pressure treatments could decrease, potentially leading to 107,000 more heart attacks and strokes over 10 years, the analysis predicts.

“The lesson from our study is that updating risk estimates without reconsidering standards of care could change treatment recommendations for millions of Americans,” said James Diao, a resident physician at Brigham and Women's Hospital and lead author of the study.

The release of the new risk tool therefore presents an opportunity to reconsider those risk thresholds, the researchers said.

“Cardiovascular disease prevention has two fundamental components: predicting risk and choosing when to treat to prevent heart attack or stroke, so it is concerning to change only one side of this equation without reconsidering the other side, which is the treatment threshold,” said Raj Manraj, assistant professor of biomedical informatics at the HMS Blavatnik Institute and lead author of the study.

Regular recalibration of risk estimates

Predicting an individual's 10-year risk of having a heart attack or stroke is a cornerstone of efforts to prevent cardiovascular disease in healthy people and to prevent recurrences in those who have had a heart attack or stroke. Such individualized risk predictions, along with other public health measures, have driven efforts to halt the toll of a disease that, despite major advances in diagnosis and treatment over the past few decades, still claims more lives in the United States and around the world than any other disease.

In November 2023, the American Heart Association unveiled an updated calculator called PREVENT, developed using more recent data that reflects demographic changes and changing trends in cardiovascular disease over the past 10 to 20 years. The new calculator provides 10-year risk estimates for patients aged 30 to 79 years and 30-year risk estimates for patients aged 30 to 59 years. Like its 2013 predecessor, the new tool includes standard cardiovascular indicators such as cholesterol and high blood pressure, but also incorporates new variables such as kidney function. Unlike previous calculators, PREVENT excludes race, recognizing the idea that race is a social rather than biological construct. The new calculator also includes the option to incorporate blood glucose, urinary protein, and neighborhood zip code, and calls for risk assessment to begin at age 30 instead of 40.

Although the American Heart Association and the American College of Cardiology have not yet formally endorsed the new calculator, some clinicians are already using the organizations' online calculator to guide patient care.

Predicting the clinical effectiveness of new computers.

The researchers based their projections on data from approximately 7,700 people aged 30 to 79 who participated in the US National Health and Nutrition Examination Survey, and applied the risk calculator to measure risk and outcomes for both 2013 and 2023.

Based on this analysis, the researchers projected that the new risk calculator would reclassify nearly half of the U.S. population into a lower-risk category. The new calculator would reclassify very few people (less than 0.5% of the population) into a higher-risk category.

The researchers then analyzed eligibility for statins and antihypertensive treatment, using current criteria that call for treatment for most moderate- and high-risk patients and focused discussion for those at borderline risk.

Under the new risk categories and current treatment standards, more than 14 million people will no longer be eligible to take statin cholesterol-lowering drugs, and 2.6 million people will no longer be eligible to take medications to control high blood pressure.

Medication changes

With the new risk calculator, 67.5 million people will receive a recommendation for statin treatment, compared with 81.8 million with the 2013 tool. The largest changes occur among men, adults in their 50s and 60s, and blacks. The analysis also shows that PREVENT estimates risk for younger patients (ages 30-79) compared with the previous calculator (adjusted for ages 40-79), but that fewer younger people (ages 30-39) are eligible for treatment with the new risk calculator. However, the researchers note that using the new risk calculator with younger age groups still provides valuable long-term risk assessments that could lead to better monitoring and prevention.

The analysis estimates that reducing the use of cholesterol-lowering statins could prevent approximately 57,000 new cases of diabetes, which are associated with an increased risk of diabetes.

Under the new risk formula, 72.7 million adults will be eligible for blood pressure medications, compared with 75.3 million under the 2013 formula. The change will primarily affect adult men ages 50 to 69 and will affect black patients more than white patients. Two percent of black adults will not be eligible for blood pressure medications, compared with 1.4% of white adults.

Overall, the analysis found that the revised risk calculation methodology would result in 15.8 million people becoming newly ineligible for statins and hypertension treatments.

New heart attacks and strokes

To estimate the number of future heart attacks and strokes that this change would result in, the researchers calculated the magnitude of risk reduction that would be lost due to lack of preventive therapy among the newly ineligible patients — in other words, they estimated the number of heart attacks and strokes that would go unprevented without treatment.

The authors estimated that 107,000 people could suffer heart attacks or strokes over the next decade as a result of ineligibility for new drugs.

The removal of race from the recalibrated calculator will result in more black Americans being assigned a lower risk and more black Americans becoming ineligible for treatment compared to the previous version of the calculator, which included race as a risk-inflating factor. However, the analysis did not predict a disproportionate increase in heart attacks and strokes among newly ineligible black Americans compared to white Americans. The researchers note that this surprising finding is likely due to existing disparities in access to preventive cardiovascular care. This means that many black people do not receive the preventive benefits of schizophrenia and blood pressure treatment in the first place, and therefore do not experience an increase in cardiovascular events due to ineligibility, according to the researchers.

“As blacks were taken off statins, we would have predicted that they would also experience disproportionately more heart attacks and strokes, but our data did not reflect this prediction,” Diao said. “We suspect this is because fewer black Americans have access to these drugs and recommended treatments in the first place. This is clearly a case where two wrongs don't make a right.”

To treat or not to treat

The researchers noted that while risk thresholds are very important at the population level and do influence treatment decisions, at the individual level, treatment decisions must always go beyond risk calculations, because no risk equation, no matter how accurate, can fully capture the risk for every patient.

The researchers noted that individualized risk assessment and treatment selection should be more than inputting variables into a digital calculator. Calculating a patient's risk is an important first step, but that risk needs to be further individualized as doctors get additional details from patients, such as family history, lifestyle, and other conditions that contribute to cardiovascular disease but aren't necessarily reflected in risk calculators. Similarly, it's important for doctors to understand patients' values ​​- their willingness to accept a higher or lower risk and their tolerance for possible side effects from treatment.

“The nuanced decision-making that needs to take place in the doctor's office means that, after careful discussion, two patients with the same estimated risk level may choose different treatment plans,” Manray said. “And that's a good thing.”