ASCVD Risk Estimator Plus Is Not Validated for Indian Populations and Likely Underestimates Risk
The ASCVD Risk Estimator Plus from the American College of Cardiology is not validated for Indian populations and likely underestimates cardiovascular risk in this group. 1 The tool was specifically developed and validated only for non-Hispanic Whites and African Americans, making it unsuitable for accurate risk assessment in Indian people without modification.
Limitations of ASCVD Risk Estimator in South Asians
Validation Issues
- The ACC/AHA Pooled Cohort Equations were derived from and validated in White and Black U.S. adults only 1
- None of the traditional risk calculators, including the ASCVD Risk Estimator Plus, have been derived from or prospectively validated in South Asian populations 1
- The 2013 ACC/AHA guidelines explicitly state that the equations are validated only for non-Hispanic African Americans and non-Hispanic Whites aged 40-79 years 1
Risk Underestimation
- The ASCVD Risk Estimator Plus systematically underestimates cardiovascular risk in South Asians 1
- South Asians have higher rates of ASCVD compared to other racial/ethnic groups, with higher proportionate mortality from ischemic heart disease 2
- South Asians tend to have multiple risk factors at younger ages, but age is a driving factor in most risk scores, leading to artificially lower scores 1
Alternative Approaches for Indian Patients
Recommended Modifications
- Some experts advocate applying a correction factor of 1.4 to 1.5 to the calculated risk score to account for the higher risk in South Asians 1
- The 2013 ACC/AHA guidelines suggest that "use of the sex-specific Pooled Cohort Equations for non-Hispanic Whites may be considered" for other populations, including South Asians 1
- Risk estimation should be adjusted upward due to the known underestimation of risk in South Asians 2
Alternative Risk Assessment Tools
- The UK QRISK2 algorithm has been derived and validated in 2.3 million people including South Asians and counts South Asian ethnicity as an additional risk factor 1
- ETHRISK is another web-based risk calculator validated in South Asians 1
- Consider CAC scoring for further risk stratification, especially in those with borderline (5% to <7.5%) or intermediate (≥7.5% to <20%) 10-year risk 2
Unique Cardiovascular Risk Profile of South Asians
Anatomical and Physiological Differences
- South Asians have smaller coronary artery luminal diameters 2
- South Asians have a higher coronary artery calcium (CAC) burden, with Asian Indian race being an independent predictor of CAC severity 2
- South Asians have higher rates of non-calcified plaque which may not be detected by CAC scoring 2
Risk Factor Prevalence
- Higher prevalence of diabetes, dyslipidemia, and metabolic syndrome in South Asians 2
- Metabolic syndrome is seen with lower waist circumference thresholds than in whites 1
- Studies in Punjab, India show that many patients with hypertension and diabetes fall into intermediate (37.8%) or high (27.9%) ASCVD risk categories 3
Clinical Approach for Indian Patients
- Use the ASCVD Risk Estimator Plus with caution, recognizing its limitations in South Asians
- Consider applying a correction factor of 1.4-1.5 to the calculated risk score
- Utilize UK QRISK2 if available as it's validated in South Asians
- Consider additional risk stratification with CAC scoring, especially for:
- Patients with borderline or intermediate risk
- Those with family history of premature ASCVD
- Patients over 60 years of age
- Pay special attention to metabolic risk factors that are more prevalent in South Asians
- Consider lifetime risk estimation for adults 20-39 years or those 40-59 years with <7.5% 10-year risk
By recognizing the limitations of the ASCVD Risk Estimator Plus in Indian populations and implementing appropriate modifications or alternative tools, clinicians can more accurately assess cardiovascular risk and implement appropriate preventive strategies for this high-risk group.