Overestimation of Performance of the AHA/ACC Atherosclerotic CVD Risk Score
What is the accuracy of the 2013 American Heart Association (AHA)-American College of Cardiology (ACC)-Atherosclerotic Cardiovascular Disease (ASCVD) risk score (Pooled Cohort) among different race/ethnic groups, and which factors are most associated with risk overestimation when preventive therapies are considered?
The Multi-Ethnic Study of Atherosclerosis (MESA), a prospective community-based cohort, was used to examine calibration and discrimination of the AHA-ACC-ASCVD risk score in 6,441 white, black, Chinese, and Hispanic Americans (aged 45–79 years and free of known ASCVD at baseline). Using univariable and multivariable absolute risk regression, the authors modeled the impact of individual risk factors on the discordance between observed and predicted 10-year ASCVD risk.
Overestimation was observed in all race/ethnic groups in MESA and was highest among Chinese (252% for women and 314% for men) and lowest in white women (72%) and Hispanic men (67%). Higher age, Chinese race/ethnicity (when compared with white), systolic blood pressure (treated and untreated), diabetes, alcohol use, exercise, lipid-lowering medication, and aspirin use were all associated with more risk overestimation, whereas family history was associated with less risk overestimation in a multivariable model (all p < 0.05). There was no effect of income or education.
The AHA-ACC-ASCVD risk score overestimates ASCVD risk among men, women, and all four race/ethnic groups evaluated in a modern American primary prevention cohort. Clinicians treating patients similar to those in the MESA study, particularly older individuals and those with factors associated with more risk overestimation, may consider interpreting absolute ASCVD risk estimates with caution.
The results are not surprising considering that the MESA participants included in this analysis appear to be more representative of contemporary Americans, as reflected in 2013–14 National Health and Nutrition Examination Survey (NHANES). In the MESA study, the observed rates were roughly half of that predicted by the Pooled Cohort risk score, and includes those in the 7.5-10% risk who are just within the statin treatment recommendation of the guidelines. I compared the CV risk of a 70-year-old white man with total cholesterol 180 mg/dl and high-density lipoprotein cholesterol 45 mg/dl, on statins and without hypertension, diabetes, smoking, or family history. The risk for the Pooled Cohort was 16.2%, and with the MESA cohort score, was 8.9% and would have been 7% if not on statins. However, if he was 55 years old, it would be 4.9% and 4.6%, respectively.
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