Association between serum interleukin-6 concentration and mortality in patients with coronary artery disease

Abstract

Objectives: To evaluate whether serum interleukin-6 (IL-6) is associated with increased risk of mortality in coronary artery disease (CAD) patients.

Methods: We performed a prospective cohort study of 718 CAD patients from the Guangzhou Cardiovascular Disease Cohort (GCDC) study. Multivariable-adjusted Cox proportional hazards regression analyses were used to examine the association between serum IL-6 with all-cause and cardiovascular mortality.

Results: During the 1663 person-years of followup, the cumulative all-cause mortality and cardiovascular mortality were 6.5% (n = 47) and 3.3% (n = 24), respectively. The mean length of followup was 2.32 ± 0.81 years. In the multivariable analyses, a one-SD increment in log-transformed serum IL-6 was positively associated with an increased risk of all-cause and cardiovascular mortality, with hazard ratios (HR) of 2.93 (95% CI, 2.11-4.08) and 2.04 (95% CI, 1.34-3.68) within the patients combined and 2.98 (95% CI, 2.12-4.18) and 3.10 (95% CI, 1.98-4.85) within males, respectively. Patients in the highest serum IL-6 tertile versus the lowest tertile were at higher risk of all-cause and cardiovascular mortality, with HR of 17.12 (95% CI 3.11-71.76) and 8.68 (95% CI, 1.88-37.51), respectively.

Conclusions: In hospitalized patients with CAD, serum IL-6 is significantly associated with all-cause and cardiovascular mortality.

Figure 1

Kaplan-Meier hazard plots for all-cause mortality by tertiles of interleukin-6. The probability values represent the trend across all three tertiles.

Figure 2

Kaplan-Meier hazard plots for cardiovascular disease mortality by tertiles of interleukin-6. The probability values represent the trend across all three tertiles.