Analysis of Calibration and Discrimination Among Multiple Cardiovascular Risk Scores | Journal Scan

Study Questions:

How does the new atherosclerotic cardiovascular risk score (American Heart Association-American College of Cardiology-atherosclerotic cardiovascular disease [AHA-ACC-ASCVD]) compare with other available tools using cardiovascular event (CVE) rates from a modern multiethnic cohort, and does preventive therapy result in risk overestimation when using the AHA-ACC-ASCVD score?

Methods:

The 10.2-year follow-up of the prospective observational MESA (Multi-Ethnic Study of Atherosclerosis) study, a community-based multiethnic cohort study in 4,227 men and women ages 50-74 years, was used to compare observed and expected events for the AHA-ACC-ASCVD risk score with four commonly used risk assessment tools. To provide a better match with the other tools in the sensitivity analysis, age, diabetic status, family history of premature coronary heart disease, and blood sugar/glycated hemoglobin were applied in the MESA cohort.

Results:

Mean age was 61.5 years, and 53.5% were women. Approximately 42% were white, 26% were African American, 20% were Hispanic, and 12% were Chinese. The AHA-ACC-ASCVD and three Framingham-based risk scores overestimated CVEs by 37-154% in men and 8-67% in women. Overestimation was noted throughout the continuum of risk. In contrast, the Reynolds Risk Score overestimated risk by 9% in men, but underestimated risk by 21% in women. Aspirin, lipid-lowering or antihypertensive therapy, and interim revascularization did not explain the overestimation.

Conclusions:

The new AHA-ACC-ASCVD score showed overestimation of risk (25-115%) in a modern, multiethnic cohort without baseline clinical ASCVD. If validated, overestimation of ASCVD risk may have substantial implications for individual patients and the health care system.

Perspective:

Many have been concerned about physicians misusing the AHA-ACC-ASCVD risk tool when deciding statin and aspirin therapy in low-risk patients for whom the risk is primarily based upon age. In men and women with a 7.5-10% 10-year risk by the 2014 risk tool, the actual observed risk was only 3% for men and 5.1% for women in the MESA participants, which was conducted in the ‘modern era.’ That preventive therapies did not explain the discrepancies in calibration (match of predictive and observed) was very surprising. While a clinical trial with decision for statins based upon the coronary calcium score would be ideal, because of the very low cost of statins, it is unlikely to ever happen. Health insurers should consider providing coverage for the coronary calcium score in intermediate-risk and some of the low-risk persons to help both calibration and discrimination.

Clinical Topics: Dyslipidemia, Prevention, Vascular Medicine, Lipid Metabolism

Keywords: Atherosclerosis, Arteriosclerosis, Lipids, Coronary Artery Disease, Risk Assessment, Risk Factors, Aspirin, Calcium, Calibration, Cohort Studies, Cardiovascular Diseases, Antihypertensive Agents, Blood Glucose, African Americans, Hispanic Americans, Secondary Prevention


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