What factors are used to calculate Atherosclerotic Cardiovascular Disease (ASCVD) risk?

How to Calculate ASCVD Risk

The ASCVD risk calculation requires age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, treatment status for hypertension, diabetes status, and current smoking status as the key variables for accurate assessment. 1

Core Variables for ASCVD Risk Calculation

The ACC/AHA Pooled Cohort Equations use the following specific risk factors:

• Demographics:

  • Age (40-79 years)
  • Sex (male/female)
  • Race (specifically White or African-American)

• Clinical Measurements:

  • Total cholesterol (mg/dL)
  • HDL cholesterol (mg/dL)
  • Systolic blood pressure (mm Hg)
  • Treatment for hypertension (yes/no)
  • Diabetes status (yes/no)
  • Current smoking status (yes/no)

2, 1

Calculation Process

The calculation involves several mathematical steps:

1. Log-transforming values for age, total cholesterol, HDL cholesterol, and systolic blood pressure
2. Calculating interaction terms between age and other variables
3. Multiplying these values by race-sex specific coefficients
4. Summing the products and calculating the 10-year risk using a specific formula 1

Race and Sex Considerations

The Pooled Cohort Equations provide separate calculations for:

• White women
• African-American women
• White men
• African-American men

For example, using identical risk factor values in a 55-year-old nonsmoker without diabetes (total cholesterol 213 mg/dL, HDL 50 mg/dL, untreated systolic BP 120 mm Hg), the 10-year ASCVD risks would be:

• 2.1% for White women
• 3.0% for African-American women
• 5.3% for White men
• 6.1% for African-American men 2

For other ethnic groups not included in the original equations (Hispanic, Asian, etc.), the equations for non-Hispanic Whites may be used, though with less certainty 2, 1.

Clinical Application

The risk calculator is designed to predict 10-year risk of "hard" ASCVD events, which include:

• Nonfatal myocardial infarction
• Fatal coronary heart disease
• Nonfatal stroke
• Fatal stroke 1

Risk categories that guide clinical decision-making:

• Higher-risk: ≥7.5% 10-year ASCVD risk
• Lower-risk: <7.5% 10-year ASCVD risk 1, 3

Limitations and Considerations

1. Age Range: The equations are validated only for adults aged 40-79 years 1

2. Ethnic Limitations: The original equations were developed using data from White and African-American populations, with less validation in other ethnic groups 2

3. Recent Updates: The 2023 PREVENT equations have updated the original Pooled Cohort Equations by removing race and adding variables for kidney function and statin use, which generally results in lower estimated risk 4

4. Risk Overestimation: Some studies have suggested the original equations may overestimate risk in certain populations 5, 6

Resources for Calculation

The ACC/AHA provides:

• A downloadable spreadsheet
• A web-based calculator available at:
  • http://my.americanheart.org/cvriskcalculator
  • http://www.cardiosource.org/science-and-quality/practice-guidelines-and-quality-standards/2013-prevention-guideline-tools.aspx 1

For accurate risk assessment, measurements should be updated every 4-6 years to improve both short-term and long-term risk prediction 2.