Interleukin-6 as an Independent Predictor of Future Cardiovascular Events in Patients with Type-2 Diabetes without Structural Heart Disease

Background: An increased serum interleukin-6 (IL-6) level is associated with a risk of cardiovascular disease. Elevated IL-6 levels are also involved in the pathogenesis of insulin resistance and can predict the development of type-2 diabetes. We tested the hypothesis that elevated IL-6 levels can predict the incidence of cardiovascular events in type-2 diabetes. Methods: Eighty-two patients with type-2 diabetes without structural heart disease (48 males; 60 ± 12 years). The initial onset of a major adverse cardiovascular event was investigated. Results: During a mean of 3.4 ± 2.0 years of follow-up, 11 patients developed cardiovascular events (3 cardiovascular deaths, 2 non-fatal myocardial infarctions, 2 coronary revascularizations, and 4 strokes). Univariate analyses revealed that elevated IL-6 level, fasting immunoreactive insulin level, and the HOMA-R were associated with cardiovascular events. Based on multivariate analyses, elevated IL-6 levels independently predicted the incidence of cardiovascular events (HR 1.17, 95% CI 1.04–1.31, P=0.015). Kaplan–Meier curves revealed that patients with a high IL-6 concentration (>2.6 pg/mL) had a higher incidence of cardiovascular events than those with non-high IL-6 concentration (≤2.6 pg/mL, P=0.031). Conclusions: These results suggest that measurement of serum IL-6 concentration is a useful tool to identify high-risk patients for cardiovascular events in type-2 diabetes.