Impact of Statins on Cardiovascular Outcomes Following Coronary Artery Calcium Scoring

Compared to traditional risk factors, coronary artery calcium (CAC) scores improve prognostic accuracy for atherosclerotic cardiovascular disease (ASCVD) outcomes. However, the relative impact of statins on ASCVD outcomes stratified by CAC scores is unknown. To determine if CAC can identify patients most likely to benefit from statin treatment. We identified consecutive subjects without pre-existing ASCVD or malignancy who underwent CAC scoring from 2002 to 2009 at Walter Reed. The primary outcome was first major adverse cardiovascular event (MACE), a composite of acute myocardial infarction, stroke, and cardiovascular death. The effect of statin therapy on outcomes was analyzed stratified by CAC presence and severity, after adjusting for baseline comorbidities with inverse probability of treatment weights based on propensity scores. 13,644 patients (mean age 50 years; 71% men) were followed for a median of 9.4 years. Comparing patients with and without statin exposure, statin therapy was associated with reduced risk of MACE in patients with CAC (adjusted subhazard ratio [aSHR] 0.76, 95% CI 0.60–0.95, p=0.015) but not in patients without CAC (aSHR 1.00, 95% CI 0.79–1.27, p=0.99). The effect of statin use on MACE was significantly related to the severity of CAC (p <0.0001 for interaction), with the NNT to prevent one initial MACE outcome over 10 years ranging from 100 (CAC 1–100) to 12 (CAC >100). In a large-scale cohort without baseline ASCVD, the presence and severity of CAC identified patients most likely to benefit from statins for the primary prevention of cardiovascular diseases. Prior studies have shown that coronary artery calcium (CAC) screening improves risk prediction of atherosclerotic cardiovascular disease (ASCVD), but the true impact of statins on ASCVD outcomes stratified by CAC scores is unknown. In this retrospective cohort of 13,644 patients without pre-existing atherosclerotic cardiovascular disease or malignancy who underwent CAC scoring at Walter Reed Army Medical Center, increasing severity of CAC was associated with increased benefit from statin treatment for the prevention of cardiovascular morbidity and mortality. CAC presence and severity may help stratify patients most likely to benefit from statins.