Interleukin-6 in Very Elderly Patients with Coronary Artery Disease

Abstract

Limited data are available on interleukin-6 (IL-6) in very elderly patients with coronary artery disease (CAD); therefore, we evaluated IL-6 levels and their relationships with various disorders. Fifty patients were enrolled in the cross-sectional study: 34 with CAD—in the study group, 16 without CAD—in the control group. Patients’ age varied from 78 to 98 years; 53.1% of patients were > 90 years. Serum IL-6 concentrations were determined by enzyme-linked immunosorbent assay. Elevated IL-6 levels were found in 49% of patients. Mean IL-6 concentration was 7.96 + 5.1 (1.5–30.6) pg/ml (N < 7.0). In patients aged < 90 years, mean IL-6 level was 6.7 + 3.2 pg/ml, in long-livers—9.1 + 6.2 pg/ml (p = 0.09). In patients with CAD, mean IL-6 concentration reached 10.9 pg/ml, in the control group—5.9 pg/ml (p = 0.02). Higher IL-6 levels were found in patients with heart failure (13.3 and 7.6 pg/ml, p = 0.04). The relative risk of high IL-6 levels in patients with heart failure was increased by 4.4. times (RR = 4.4; p = 0.02). Among patients with hyperuricemia, mean IL-6 values were 10.5 + 3.1 pg/ml, with normal uric acid—7.1 + 3.1 pg/ml (p = 0.001). Relative risk of high IL-6 levels in patients with hyperuricemia was increased by 9.7 times (RR = 9.7; p = 0.003). Positive correlations were found between IL-6 and tumor necrosis factor-α (R = 0.34; p = 0.01), creatinine (R = 0.35; p = 0.01), and urea (R = 0.28; p = 0.05) concentrations. Regression analysis demonstrated that the most important factor for IL-6 levels was hyperuricemia (β = 0.7, p = 0.00003). The results of the study demonstrated a frequent IL-6 increase in very elderly patients with CAD along with relationships between IL-6, heart failure, and hyperuricemia.