Warranty period of zero coronary artery calcium score for predicting all-cause mortality according to cardiac risk burden in asymptomatic Korean adults

Background: The aim of this study was to examine whether zero coronary artery calcium (CAC) score is associated with favorable prognosis of all-cause mortality (ACM) according to a panel of conventional risk factors (RF) in asymptomatic Korean adults. Methods and Results: A total of 48,215 individuals were stratified according to presence/absence of CAC, and the following RF were examined: hypertension, diabetes, current smoking, high low-density lipoprotein cholesterol, and low high-density lipoprotein cholesterol. The RF were summed on composite score as 0, 1–2, or ≥3 RF present. The warranty period was defined as the time to cumulative mortality rate >1%. Across a median follow-up of 4.4 years (IQR, 2.7–6.6), 415 (0.9%) deaths occurred. Incidence per 1,000 person-years for ACM was consistently higher in subjects with any CAC, irrespective of number of RF. The warranty period was substantially longer (eg, 9 vs. 5 years) for CAC=0 compared with CAC >0. The latter observation did not change materially according to pre-specified RF, but difference in warranty period according to presence/absence of CAC reduced somewhat when RF burden increased. Conclusions: In asymptomatic Korean adults, the absence of CAC evoked a strong protective effect against ACM as reflected by longer warranty period, when no other RF were present. The usefulness of zero CAC score and its warranty period requires further validation in the presence of multiple RF.