Budoff MJ, et al. - Researchers determined the association of coronary artery calcium (CAC) with atherosclerotic cardiovascular disease (ASCVD) events, using the population-based MESA cohort with over 10 years of follow-up. They also investigated if this link varied by sex, race/ethnicity, or age category. Independent of standard risk factors, and similarly by age, gender, and ethnicity, CAC was shown to be related strongly and in a graded fashion to 10-year risk of incident ASCVD, as it is for coronary heart disease (CHD). With CAC=0, 10-year event rates were almost exclusively below 5%, while they were consistently above 7.5% in those with CAC ≥ 100, making these potentially valuable cutpoints for the consideration of preventive therapies. CAC was considered as the most useful markers for predicting ASCVD risk as it strongly predicted risk with the same magnitude of effect in all races, age groups, and both sexes.

Methods

• Researchers used a prospective multi-ethnic cohort study (MESA) of 6,814 participants (51% women), aged 45–84 years, free of clinical CVD at baseline.
• Using Cox regression models adjusted for age, race/ethnicity, sex, education, income, cigarette smoking status, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, diabetes, lipid-lowering medication, systolic blood pressure, antihypertensive medication, intentional physical exercise, and body mass index, the link between CAC and incident ASCVD was assessed.
• The analysis included only the first event for each individual.

Results

• Over a median of 11.1 years, 500 incident ASCVD (7.4%) events were reported.
• The following were included as hard ASCVD: 217 myocardial infarction, 188 strokes (not transient ischaemic attack), 13 resuscitated cardiac arrest, and 82 CHD deaths.
• Researchers found that event rates in those with CAC=0 Agatston units ranged from 1.3% to 5.6%, while for those with CAC > 300, the 10-year event rates ranged from 13.1% to 25.6% across different age, gender, and racial subgroups.
• Regardless of demographic subset, >7.5% risk was noted for all participants with CAC > 100 at 10 years of follow-up.
• Irrespective of age, sex, or race/ethnicity, a steady increase in 10-year ASCVD event rates was noted across CAC categories.
• For each doubling of CAC, researchers estimated a 14% relative increment in ASCVD risk, holding all other risk factors constant.
• Age, sex, race/ethnicity, or baseline lipid-lowering use did not significantly modify this link.