External validity of a cardiovascular screening including a coronary artery calcium examination in middle-aged individuals from the general population.

Background Coronary artery calcium is important in cardiovascular risk stratification, but this knowledge is based on studies with a significant selection bias. This study aims to evaluate the external validity of a screening programme including coronary artery calcium examination, and the association between coronary artery calcium and cardiovascular events. Design Multi-centre population based study. Methods Randomly selected middle-aged men and women ( N = 1751) free of cardiovascular disease were invited to the examination during 2009-2010. Participation rate in the examination was 70%. Participants ( n = 1227) and non-participants ( n = 524) were compared regarding: cardiovascular medical treatment, Charlson comorbidity index and socioeconomic status (evaluated by cohabitation, gross income and education). Study endpoints were cardiovascular events and mortality. Results Non-participants had a significant higher comorbidity ( p = 0.003) and a lower socioeconomic status ( p < 0.0001), while cardiovascular medical treatment was alike. Over a median follow-up time of 6.5 years the cardiovascular event and mortality rates were equal (6.7% vs. 6.4%, p = 0.80 and 0.4% vs. 0.5%, p = 0.76, respectively). Adjusted hazard ratio was 0.90 (95% confidence interval (CI) 0.63-1.37). Among participants, the extent of coronary artery calcium was significantly associated with increased risk of cardiovascular events (hazard ratio 1.92, 95% CI 1.03-3.54, hazard ratio 3.66, 95% CI 1.82-7.32, hazard ratio 6.51, 95% CI 3.17-13.36 for coronary artery calcium scores 1-99, 100-399, ≥400 AU, respectively). Conclusions Non-participants had a higher comorbidity index and a lower socioeconomic status, but the cardiovascular event and mortality rates were equal to those of participants. Thus, a screening programme including a coronary artery calcium examination had a high external validity regarding cardiovascular risk, but also a significant social imbalance.

Association between high-sensitive troponin I and coronary artery calcification in a Danish general population.

BACKGROUND: High-sensitive troponin I (hs-TnI) is an individual predictor of future cardiovascular disease (CVD). However, the relationship between hs-TnI and coronary artery calcification (CAC) as determined by computed tomography (CT) has not previously been investigated in a general population. METHODS: 1173 randomized, middle-aged subjects without known CVD underwent a non-contrast cardiac-CT scan for CAC determination. Hs-TnI was detected using ARCHITECT STAT High Sensitive Troponin-I immunoassay. Total 10-year cardiovascular mortality risk was estimated using HeartScore. The relationship between hs-TnI and CAC was assessed using logistic regression analyses and receiver operating characteristic curves (ROC). RESULTS: Concentrations of hs-TnI above the limit of detection were measured in 89.3% of all subjects. Presence of CAC (Agatston score >0) was detected in 29% in the lowest hs-TnI quartile compared with 55% in the highest, with a stepwise increase over the quartiles. In fully adjusted regression models with dichotomous CAC outcomes, hs-TnI was able to predict presence of CAC (OR: 1.25, 95% CI: 1.03-1.51, p = 0.025) and an Agatston score >100 (OR: 1.36, 95% CI: 1.08-1.71, p = 0.009). Subjects in the fourth hs-TnI quartile had an increased risk for presence of CAC (OR: 1.56, 95% CI: 1.06-2.26, p = 0.024) and for an Agatston score >100 (OR: 1.82, 95% CI: 1.04-3.18, p = 0.035), when compared with the first quartile. Addition of hs-TnI to HeartScore improved the ROCAUC from 0.671 to 0.695 (p < 0.0001). CONCLUSION: Hs-TnI was associated with CAC in a Danish middle-aged population without previously known CVD. This is a step towards understanding hs-TnI as a risk marker for CVD.