When Does a Calcium Score Equate to Secondary Prevention?

Quick Takes

  • In adults with no history of ASCVD, rates of CV risk factors increased with increases in CAC scores.
  • The prevalence of hyperlipidemia, hypertension, diabetes mellitus, and smoking was similar among those with CAC score >300 and those with established ASCVD.
  • Adults with no history of ASCVD but with a CAC >300 have event rates comparable to those with established ASCVD, while lower CAC among those without a history of ASCVD was associated with a significantly lower risk for MACE compared to those with established ASCVD.

Study Questions:

What level of elevated coronary artery calcification (CAC) scores among adults without an atherosclerotic cardiovascular disease (ASCVD) event should be recommended for aggressive CV risk modification, similar to those with a history of an ASCVD event?


Data from the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry were used to compare ASCVD event rates in persons without a history of myocardial infarction (MI) or revascularization to event rates among persons with established ASCVD. CAC was categorized as 0, 1-100, 101-300, and >300. The primary outcome was a composite of major adverse cardiovascular events (MACE), which included all-cause mortality, nonfatal MI, and hospitalization for unstable angina. Secondary outcomes included MACE plus late revascularization (>90 days), MI, and all-cause mortality.


A total of 4,949 patients (4,511 with no ASCVD history and 438 with a prior history of ASCVD) were included (mean age 57.6 ± 12.4 years, and 56% male). Rates of CV risk factors included hypertension (60%), elevated cholesterol levels (56%), diabetes mellitus (16%), and past smoking (22%). Median follow-up was 4.7 years during which time there were 254 (5%) deaths, 229 (5%) MI events, 442 (9%) MACE events, and 583 (12%) MACE plus late revascularization events. No difference in risk for a MACE event was observed between patients with CAC score >300 and no prior ASCVD versus those with established ASCVD (52.8 vs. 53.6 events per 1,000 person-years, p = 0.763). Similarly, no difference was noted for MACE and late revascularization (p = 0.855), MI (p = 0.672), or all-cause mortality (p = 0.690).

Among patients without ASCVD, a CAC score was associated with a significant lower risk for MACE, including a CAC score of 0 (adjusted hazard ratio [aHR], 0.31; 95% confidence interval [CI], 0.22–0.45; p < 0.001), CAC of 1-99 (aHR, 0.41; 95% CI, 0.30–0.57; p < 0.001), or CAC of 100-299 (aHR, 0.59; 95% CI, 0.42–0.84; p = 0.003) compared to those with prior ASCVD. However, a CAC score >300 was not statistically significantly different for risk of MACE compared to those with prior ASCVD (aHR, 0.944; 95% CI, 0.717–1.244; p = 0.683).


The authors concluded that patients with CAC scores >300 are at an equivalent risk of MACE and its components as those treated for established ASCVD.


These data suggest that a CAC score of >300 carries a similar risk for CVD events as those with a history of established ASCVD. Given the higher rates of established risk factors among those with elevated CAC, aggressive risk factor management may reduce CV event rates.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Cardiac Surgery and Arrhythmias, Interventions and ACS, Interventions and Imaging, Computed Tomography, Nuclear Imaging

Keywords: Acute Coronary Syndrome, Atherosclerosis, Computed Tomography Angiography, Myocardial Revascularization, Secondary Prevention

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