Interleukin-18 Is a Strong Predictor of Cardiovascular Death in Stable and Unstable Angina

TLDR

Interleukin‑18 drives atherosclerosis and plaque vulnerability in animal models, yet epidemiologic evidence linking its levels to cardiovascular outcomes is scarce. The study prospectively measured baseline serum IL‑18 and other inflammatory markers in 1,229 patients with documented coronary artery disease. Higher IL‑18 concentrations were independently associated with a 3.3‑fold increased risk of cardiovascular death, a relationship that persisted across stable and unstable angina and remained significant after adjustment for confounders.

Abstract

Background — Interleukin (IL)-18 plays a central role in orchestrating the cytokine cascade and accelerates atherosclerosis and plaque vulnerability in animal models. However, epidemiological data evaluating the role of IL-18 levels in atherosclerosis are lacking. Methods and Results — In a prospective study of 1229 patients with documented coronary artery disease, we measured baseline serum concentrations of IL-18 and other markers of inflammation. During the follow-up period (median, 3.9 years), 95 patients died of cardiovascular causes. Median serum concentrations of IL-18 were significantly higher among patients who had a fatal cardiovascular event than among those who did not (68.4 versus 58.7 pg/mL; P <0.0001). The hazard risk ratio of future cardiovascular death increased with increasing quartiles of IL-18 (hazard risk ratio, 1.46; 95% CI 1.21 to 1.76; P for trend <0.0001). After adjustment for most potential confounders, including the strong predictor ejection fraction as well as the inflammatory variables IL-6, high-sensitive C-reactive protein, and fibrinogen, this relation remained almost unchanged, such that patients within the highest quartile of IL-18 had a 3.3-fold increase in hazard risk compared with those in the first quartile (95% CI, 1.3 to 8.4, P =0.01). This relation was observed in patients with stable angina and patients with unstable angina at baseline. Conclusions — Serum IL-18 level was identified as a strong independent predictor of death from cardiovascular causes in patients with coronary artery disease regardless of the clinical status at admission. This result strongly supports recent experimental evidence of IL-18–mediated inflammation leading to acceleration and vulnerability of atherosclerotic plaques.