Do Coronary Artery Calcium Scores Improve Risk Assessment for Individuals with Low Socioeconomic Status?

Low socioeconomic status (SES) has been linked closely to the development of atherosclerotic cardiovascular disease (ASCVD), conferring a level of risk similar to traditional risk factors. Typical risk estimation calculators, including pooled cohort equations such as the ACC/AHA 10-year ASCVD Risk Estimator, generally underestimate risk in individuals with low SES. Coronary artery calcium (CAC) scores derived from noncontrast CT scans enhance ASCVD risk prediction in the general population. We questioned whether CAC scores improved ASCVD risk assessment in individuals with low SES.

Using the Dallas Heart Study, we identified 2,200 individuals without ASCVD and with CAC scans and stratified them by SES. Low SES was defined either by education attainment fewer than 12 years or annual income less than $16,000. Age, gender, BMI, LDL, and creatinine were similar among individuals with low and higher SES. Individuals with low SES were more likely to identify as Black and had a higher incidence of hypertension, diabetes, and tobacco use.

In 12 years of follow up, we found that low SES was associated with increased ASCVD events but was not independently associated with CAC on CT. Higher CAC scores tracked with a higher ASCVD event rate in all individuals, but those with low SES carried greater ASCVD risk for every stratum of CAC, including those with CAC scores of zero. In fact, the 10-year ASCVD risk in those with low SES and CAC of 0 was approximately 5%. Higher CAC scores were independently associated with ASCVD in multivariable models in individuals with higher SES only. Finally, we found that adding CAC scores to pooled cohort equation risk estimators improved risk discrimination for individuals at higher SES but not for those with low SES.

In summary, individuals with low SES are at significantly increased risk for ASCVD events. Unfortunately, CAC scanning may be less useful in these individuals compared to those at higher SES. This study highlights the importance of considering low SES as an ASCVD risk indicator, even in those with low CAC scores.