A Danish cohort study showed that the diagnostic value of a coronary artery calcium (CAC) score was age dependent, with smaller added diagnostic value for younger patients. The cohort included 23 759 symptomatic adult patients who underwent computed tomography angiography between January 2008 and December 2017; median age 58, 55% women, 54% with a CAC score of 0, and a median follow-up time of 4.3 years. The prevalence of obstructive coronary artery disease (CAD), defined as 50% or more luminal stenosis, ranged from 3% in those who were younger than 40 years to 8% among those who were 70 years or older. In patients with obstructive CAD, 14% had a CAC score of 0, and the prevalence decreased with age groups from 58%, 34%, 18%, 9%, to 5% among those who were younger than 40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, and 70 years or older, respectively. Across the age spectrum, a substantially higher proportion of women with obstructive CAD had a CAC score of 0 as compared with men. The added diagnostic value of a CAC score of 0 decreased at a younger age, with a risk factor–adjusted diagnostic likelihood ratio of a CAC score of 0 ranging from 0.68 (approximately 32% lower likelihood of obstructive CAD than expected) in those who were younger than 40 years to 0.18 (approximately 82% lower likelihood than expected) in those who were 70 years or older. The presence of obstructive vs nonobstructive CAD among those with a CAC score of 0 was associated with a multivariable adjusted hazard ratio of 1.51 for myocardial infarction and all-cause death; however, this hazard ratio varied from 1.80 in those who were younger than 60 years to 1.24 in those who were 60 years or older. The findings suggest that the absence of CAC is not equivalent to the absence of atherosclerosis, particularly in younger adults and women. Source: https://jamanetwork.com/
