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Updated: Jul 2, 2025
Author Spotlight: Advancing Cardiovascular Imaging - Introducing the Spatially Weighted Calcium Score for Early Disease Detection
Published on: September 22, 2023
Differences and Disparities Among Self-Referred and Physician-Referred Populations Undergoing Coronary Artery Calcium
Nathan Marzlin1, Andrew Chapel1, James Adefisoye1
1Aurora Cardiovascular and Thoracic Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Advocate Aurora Health, University of Wisconsin School of Medicine and Public Health, Milwaukee, WI (N.M, A.C, J.A, S.W., D.P, M.P, L.M., D.H., R.J., S.P., P.G.).
Insights
Coronary artery calcium (CAC) scans are often out-of-pocket. Patients in higher income areas are more likely to get CAC tests, despite those in lower income areas having more cardiovascular risk factors.
Area of Science:
- Cardiology
- Radiology
- Public Health
Background:
- Coronary artery calcium computed tomography (CAC) is crucial for identifying subclinical atherosclerosis and cardiovascular risk.
- Despite guidelines, some insurers consider CAC investigational, leading to out-of-pocket expenses.
- CAC testing can be accessed via self-referral (SR) or physician referral (PR).
Purpose of the Study:
- To examine differences in patient, socioeconomic, and CAC characteristics between SR and PR groups.
- To understand disparities in accessing CAC testing based on referral type and socioeconomic status.
Main Methods:
- Evaluated demographic, medical history, and CAC results of 19,726 patients from March 2019 to June 2021.
- Categorized patients into SR and PR groups.
- Analyzed socioeconomic variables (income, education) at the block level using census data.
Main Results:
- SR patients were more likely women and resided in higher-income areas compared to PR patients.
- SR patients had a higher likelihood of a CAC score of 0 (41.2%), while PR patients had a higher prevalence of CAC >300 (16.8%).
- Patients from low-income areas were underrepresented in both referral groups.
Conclusions:
- Out-of-pocket CAC testing is predominantly accessed by individuals in medium- and high-income areas.
- Lower-income individuals, despite higher cardiovascular disease risk, are less likely to obtain CAC testing.
- Policy considerations are needed to promote health equity and improve CAC testing utilization among underrepresented groups.
Background:
Coronary artery calcium computed tomography (CAC) is an important tool for identifying subclinical atherosclerosis and cardiovascular risk stratification. Despite robust evidence and inclusion in current guidelines, CAC is considered investigational by some US insurance carriers and requires out-of-pocket expenses. CAC can be obtained via self-referral (SR) or physician referral (PR). We aimed to examine differences in patient, socioeconomic, and CAC characteristics between referral groups.
Methods:
We evaluated demographic, medical history, and CAC results of consecutive patients with a CAC completed at one of multiple Wisconsin sites from March 1, 2019, to June 30, 2021. We separated patients into SR and PR groups. Through census data, we analyzed socioeconomic variables at the block level including race and ethnicity, median income, average household size, and high school completion in the areas where patients resided at the time of CAC.
Results:
The final analysis included 19 726 patients: 13 835 (70.1%) PR and 5891 (29.9%) SR. Most patients in both groups were White (95.2% versus 95.1%), with the Black/African American population representing 2.7% (SR) and 2.3% (PR). The PR group had a higher prevalence of cardiovascular risk factors. SR patients were more likely to have a score of 0 (41.2% versus 38.1%; P<0.001); PR patients had a higher prevalence of CAC >300 (16.8% versus 14.8%; P<0.001). SR patients were more likely to be women (55.1% versus 48.9%; P<0.001) and were found to live in higher income areas (19.5% versus 16.4%; P<0.001). Patients from low-income areas comprised the smallest proportion in both groups (7.5%).
Conclusions:
Patients who obtain out-of-pocket CAC live predominantly in medium- and high-income areas, and patients from lower income locations are less likely to obtain CAC despite having more cardiovascular disease risk factors. Consideration should be made from a policy perspective to promote health equity and improve utilization of CAC testing among underrepresented groups.
