Soluble urokinase plasminogen activator receptor is in contrast to high-sensitive C-reactive-protein associated with coronary artery calcifications in healthy middle-aged subjects

Objective: The main objective of this study was to investigate the association between two markers of low-grade inflammation; soluble urokinase plasminogen activator receptor (suPAR) and high-sensitive C-reactive protein (hs-CRP); and coronary artery calcification (CAC) score detected by cardiac computed tomography (CT) scan. Design: A cross sectional study of 1126 randomly sampled middle-aged men and women. Methods: CAC score was measured by a non-contrast cardiac CT scan and total 10-year cardiovascular mortality risk was estimated using the Systematic Coronary Risk Evaluation (SCORE). Plasma samples were analysed for suPAR and hs-CRP. The association of suPAR and hs-CRP to CAC was evaluated by logistic regression analyses adjusting for categorised SCORE. The additive effect of suPAR to SCORE was evaluated by comparing area under curve (AUC) and net reclassification improvement (NRI). Results: The odds of being in a higher CAC category, i.e. having more severe CAC, increased 16% (odds ratio (OR) 1.16, p=0.02) when plasma suPAR concentration increased 1ng/ml, and this was more pronounced in women (OR 1.30, p=0.01) than in men (OR 1.15, p=0.05). In comparison, hs-CRP was not associated with CAC category (OR 1.00, p=0.90). When adding suPAR to categorised SCORE, AUCincreased from 0.66 to 0.70 (p=0.04) in women and from 0.65 to 0.68 (p=0.03) in men. NRIwassignificant in men (NRI 19.3%, 95% CI 6.1-32.6, p=0.004) as well as in women (NRI 20.8%, 95%CI 1.0-40.7, p=0.04), without significant gender difference. Conclusions: suPAR, but not hs-CRP, appeared to be associated with CAC score independently of SCORE. The association was strongest in women.