Impact of coronary artery calcification on all-cause mortality in individuals with and without hypertension

Background: Coronary artery calcium (CAC) has emerged as an important prognostic indicator for coronary heart disease risk. The purpose of this study was to assess the impact of increasing CAC burden among those with and without hypertension (HTN). Methods: The study cohort consisted of 44,052 consecutive asymptomatic individuals free of known coronary heart disease referred for electron beam computed tomography (EBT) for the assessment of subclinical atherosclerosis. 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 from any cause. Results: About one third (34%) of the subjects were affected by hypertension. There were 901 deaths (2.05%) in the total study population over a mean follow-up of 5.6 ± 2.6 years (range 1-13 years). The lowest event rate was observed in those with no CAC among those without hypertension (1.6 events per 1000 person years), whereas those with CAC ≥400 and hypertension had the highest all fatality rate (9.8 per 1000 person years). Compared to a CAC score of 0, increasing CAC scores (1-99, 100-399, and ≥400) were associated with increases in all-cause mortality. The hazard ratio was 2.19-7.74-fold among those without HTN and 3.00-5.83 fold among those with HTN. Overall likelihood ratio chi square statistics demonstrated that the addition of CAC scores increased mortality prediction beyond traditional risk among those with hypertension. Conclusion: Addition of CAC scores contributed significantly in predicting mortality in addition to just traditional risk factors alone among those with and without hypertension.