Background: Recent investigations suggest the inclusion of inflammatory markers in the definition of the metabolic syndrome (MS). The aim of this study was to address the role of C-reactive protein, fibrinogen, interleukin-6 (IL-6) and IL-18 (IL-18) on cardiovascular prognosis in accordance to MS.
Methods: A total of 1263 patients with documented coronary artery disease were prospectively included. We defined MS (MS yes: N=533, 42.2%) as the presence of at least three of the following criteria: triglycerides>or=150 mg/dl; low high-density lipoprotein cholesterol (men: <40 mg/dl women: <50 mg/dl); body mass index greater than 30 kg/m; blood pressure>or=130/85 mmHg; fasting glucose>or=100 mg/dl. In addition, we determined C-reactive protein, fibrinogen, IL-6 and IL-18 levels.
Results: Follow-up data (median 6.1 years) were available for 1257 patients (99.5%). 139 patients (11.1%) died from cardiovascular causes. Cardiovascular mortality was related to MS (MS yes: 15.1% versus MS no: 8.1%, P<0.0001) and was further increased by elevation of each inflammatory marker. To address whether elevation of inflammatory markers provides additional prognostic information, a subgroup analysis was performed including patients with MS. In a multivariate-adjusted model including all four inflammatory markers, only IL-18 could be identified as an independent predictor of cardiovascular mortality.
Conclusion: The measurement of inflammatory markers, especially IL-18, adds important prognostic information with regard to the long-term prognosis of patients with MS.