Abstract 18506: Interaction of Coronary Artery Calcification and Increasing Burden of Traditional Risk Factors on All Cause Mortality
Objectives: We sought to examine the interplay between increasing burden of traditional risk factors (RF) and coronary artery calcium (CAC), for the prediction of all cause mortality.
Methods: The study cohort consisted of 44,052 consecutive asymptomatic individuals free of known coronary heart disease referred for non contrast computed tomography (CT) for the assessment of CAC. The following risk factors were considered in our study. 1) Cigarette smoking, 2) Dyslipidemia, 3) Diabetes Mellitus, 4) Hypertension, and 5) Family history of CHD. Patients were followed for a mean of 5.6 ± 2.6 years (range 1 - 13 years). The primary endpoint for the study cohort was mortality.
Results: Overall no RF were found in 18,819 subjects (43%), whereas 10,093 (23%), 8,754 (20%) and 6,386 (14%) reported 1, 2 and ≥3 RF respectively. Additionally, 19,898 patients (45%) had no CAC, whereas 14,181 (32%) had CAC scores of 1-100, 5,739 (13%) had CAC scores of 101-400, and 4,234 (10%) had CAC>400. Annualized mortality rates for those 0, 1, 2, and ≥3 RF were 1.84, 4.13, 5.78 and 9.11 deaths/1,000 person-years respectively. Annualized mortality rates for those with CAC scores 1-100, 101-400 and ≥400 were 0.87, 2.97, 6.90 and 17.68 deaths/1,000 person-years respectively. After adjusting for age/gender when both RF and CAC were considered simultanously in multivariate analysis, the hazard ratio (HR) for all cause mortality increased from 1.72 to 3.15 fold with increasing RF (1 to≥3) , and from 2.53 to 7.52 with CAC scores (1-100 to >400). As compared to individuals with CAC=0 and no RF (ref group), the HR for all cause mortality was 21 fold higher among those with CAC>400 but no RF, whereas the corresponding HR was only 8 fold higher among individuals with ≥3 RF, but no CAC. The greatest risk of all cause mortality was noted among those with highest number of RF and CAC>400 (HR=32).
Conclusions: While both RF and CAC were associated with increasing risk, CAC discriminates risk over a wider range than traditional RF alone.
- © 2010 by American Heart Association, Inc.