Abstract:Objective Previous studies suggest that inflammation factors are elevated in patients with atrial fibrillation (AF). However, coronary artery disease (CAD), which is often present in the same populations, is related to the raising of iflammation markers, and may present as a confounder in these studies. We therefore examined the association between biomarkers of inflammation and AF in patients with known CAD.Methods We performed a cross-sectional analysis of 670 patients with stable coronary artery diseases from July 2008 to June 2011, 32 of whom had AF. Interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-α(TNF-α), monocyte chemoattractant protein-1 (MCP-1), and fibrinogen (Fg) levels were determined in all the patients. Results In the CAD patients with or without AF, demographic characteristics were different. Age, rate of male, smoking status, history of heart failure, and left atrial volume were higher in patients with AF. In unadjusted analyses, IL-6 was the only biomarker significantly associated with AF (median IL-6 3.54 and 2.36 ng/L in those with and without AF, respectively, P=0.001). Based on multivariate analysis, IL-6 was also the only factor related to AF (Odds Ratio 1.7, 95% CI: 1.32-2.14, P=0.024). Conclusions In patients with CAD, AF is significantly associated with elevated IL-6 levels. No associations were found with other biomarkers, including C-reactive protein, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fibrinogen levels.