High CAC score associated with increased mortality in young adults
Association of Coronary Artery Calcium With Long-term, Cause-Specific Mortality Among Young Adults
Introduction and methods
Estimation of 10-year absolute risk of CVD is recommended by multiple CV guidelines to guide therapy decisions . An important determinant of coronary heart disease (CHD) and 10-year risk of CVD is age, resulting in estimation of low 10-year risk of CVD in young adults, even though they have nonoptimal CV risk factor and an elevated lifetime risk of CVD . Early treatment in young adults may result in great benefits, but it is unclear who and when to treat young adults .
Coronary artery calcium (CAC), a marker of atherosclerosis, can be used to stratify risk in individuals without known CVD and help to identify those who need preventive therapies [4-6]. This has been demonstrated in middle-aged adults, but CAC studies in younger adults had limitations: small sample size, short follow-up and lack of cause-specific mortality [7-9].
Data from the CAC Consortium was used to examine whether CAC can identify young adults at high risk for CVD. The CAC Consortium was an investigator-initiated, multicenter, retrospective cohort including subject ≥18 years without CVD or CV symptoms from 1991-2010 with follow-up until June 2014 . Clinical indications for CAC testing included individuals with CVD risk factor(s) who were uncertain about their absolute CVD risk. Participants ≥50 years and <30 years were excluded, leaving 22346 subjects for this analysis. Mean age was 43.5 (SD: 4.5) years.
CAC was measured by computed tomography (CT) and quantified using the Agatston method with CAC score categories of 0, 1 to 100, and >100. Outcomes of interest were CHD, CVD and total mortality. Mean follow-up was 12.7 (SD: 4.0) years.
- Prevalence of any CAC was 34.4% (number needed to screen to detect CAC=3), while 7.2% of participants had a CAC score >100 (number needed to screen to detect CAC >100=14).
- Rate of CHD mortality per 1000 person-years was 4-fold higher in individuals with any CAC (0.27 CHD-related deaths per 1000 person-years; 95%CI: 0.19-0.40) and 10-fold higher in individuals with a CAC score >100 (0.69 CHD-related deaths per 1000 person-years; 95%CI: 0.41-1.16) compared with individuals with a CAC score of 0 (0.07 CHD-related deaths per 1000 person-years; 95%CI, 0.04-0.12).
- After adjustment for traditional risk factors, risk of CHD death remained significantly increased in individuals with a CAC score >100 (HR: 5.6; 95%CI: 2.5-12.7), as were risk of CVD mortality (HR: 3.3; 95%CI: 1.8-6.2) and all-cause mortality (HR: 2.6; 95%CI: 1.9-3.6) compared with those with a CAC score of 0.
CAC score >100 is associated with an increased risk of CHD, CVD and total mortality in young individuals (30-49 years) without CVD. These results suggest that CAC testing may be considered for risk stratification in young adults with elevated CV risk.