Uric Acid and Coronary Artery Disease, Two Sides of a Single Coin: A Determinant of Antioxidant System or a Factor in Metabolic Syndrome

Introduction: Uric acid has antioxidant activity and it is expected to protect against coronary artery disease (CAD). Contradictory, it is a component of metabolic syndrome and so a risk factor for CAD. The associations of plasma total antioxidant capacity (TAOC) and uric acid (UA) as well as other risk factors were investigated relative to the occurrence and severity of CAD. M aterials and Methods: The study population consisted of 148 males and 152 females aged 35-76 years who were classified as CAD cases and controls according to the results of coronary angiography. The severity of CAD was scored on the basis of the number and the extent of lesions at coronary arteries. The concentrations of UA and TAOC were measured by using of FRAP and enzymatic uricase methods. Results: The prevalence of hypertension, cigarette smoking and diabetes mellitus was more frequent in CAD cases than controls. Patients with CAD when compared with the controls had increased levels of glucose, triglycerides, creatinine, UA, TAOC and decreased levels of HDL-cholesterol. Serum UA was high positive correlate of serum total and LDL-cholesterol, triglyceride, creatinine, BUN, bilirubin, TAOC and negative correlate of glucose and HDL-C. TAOC and its major determinant UA but not bilirubin and albumin are significantly associated with the prevalence and severity of CAD. In multivariate analysis and in the absence of hypertension, UA but not TAOC would remain and be associated with CAD by the OR of 1.57 (1.072.29), p= 0.02. If the results adjusted for all major risk factors including hypertension, neither TAOC nor UA would remain in the regression equation. Conclusion: The results suggest that TAOC and UA but not bilirubin and albumin are associated with CAD significantly. But, the correlation is not independent and is attributed to the metabolic syndrome. The measurement of UA and TAOC will not improve the prognostic power beyond the classical risk factors.