Abstract
BACKGROUND AND AIMS: A large proportion of statin eligible candidates have a baseline absence of coronary artery calcium (CAC) and low 10-year atherosclerotic cardiovascular disease (ASCVD) risk. We sought to determine the proportion of statin eligible individuals who had long-term healthy arterial aging (persistent CAC = 0) and their examined 15-year ASCVD outcomes. METHODS: We included 561 statin eligible candidates from the Multi-Ethnic Study of Atherosclerosis who were not on statin therapy with CAC = 0 at Visit 1 (2000-02) and underwent a subsequent CAC scan at Visit 5 (2010-11). Adjusted Cox proportional hazards regression assessed the association between persistent CAC = 0 and ASCVD events over 15.9 years. RESULTS: Participants were on average 61.7 years old, 50% were women, and 43% maintained long-term CAC = 0. Individuals with an LDL-C ≥190 mg/dL (54%) and those with an ASCVD risk ≥20% (33%) had the highest and lowest proportion of persistent CAC = 0, respectively. There were 57 ASCVD events, and 15-year ASCVD event rates were low for individuals with and without healthy arterial aging (4.3 versus 8.6 per 1,000 persons-years), but the 10-year number needed to treat to prevent one ASCVD event differed by more than two fold (117 versus 54). In multivariable modeling, persistent CAC = 0 conferred a 51% lower risk of ASCVD compared to those with incident CAC (HR = 0.49, 95% CI: 0.27-0.90, p=0.02). CONCLUSIONS: More than 40% of statin eligible individuals with baseline CAC = 0 had long-term healthy arterial aging. Statin eligible candidates with persistent CAC = 0 had a very low 15-year ASCVD risk, suggesting that statin therapy may be of limited benefit among this group of individuals.