Serum bilirubin concentration in patients with an established coronary artery disease.

Bilirubin has been considered an antioxidant, with capacity to remove reactive species of oxygen. Studies have suggested that an increased bilirubin level promotes protection against atherosclerosis. The case group was composed of 100 patients with coronary artery disease and the control group 100 patients with normal coronaries. Blood samples were collected to determine bilirubin concentrations. Bivariate analysis, multiple logistic regression models, and Spearman's correlation index were performed. A P value < 0.05 was considered to be significant. The case group was predominantly composed of men and the control group of women, with a mean age of 60 +/- 8.8 versus 56 +/- 10.9 (P = 0.015). The total bilirubin average was significantly higher in the control group than in the case group (0.76 mg/dL versus 0.39 mg/dL, P < 0.001). The level of ultrasensitive C reactive protein (us-CRP) was increased in the case group (3.63 mg/L versus 0.93 mg/L, P < 0.001). Although the correlation index for this inverse association has been weak, both are independently associated with a higher prevalence of coronary artery disease, total bilirubin <or= 0.56 mg/dL (OR: 10.04; IC: 3.48-28.90; P < 0.001), and ultrasensitive C reactive protein > 3 mg/L (OR: 1.17; IC: 1.04-1.33; P = 0.009). Reduced serum levels of bilirubin were shown to be associated with a higher prevalence of coronary artery disease emerging as a new potential risk factor marker. Additional studies are still necessary to confirm and demonstrate the association of these findings with clinical outcomes.