The Interleukin 6 Protein Level as well as a Genetic Variants, (rs1800795, rs1800797) Are Associated with Adverse Cardiovascular Outcomes within 10-Years Follow-Up

Background: Worldwide, cardiovascular disease (CVD) is the leading cause of premature death. The proinflammatory cytokine interleukin 6 (IL-6) is a essential marker of innate immunity that is considered to play an important proatherogenic role for cardiovascular disease. The aim of this study (substudy of ClinTrials.gov identifier: NCT01045070) was to evaluate IL-6 protein level and genetic variants (rs1800795, rs1800797) with respect to CV outcome (combined endpoint: myocardial infarction, stroke/transient ischemic attack, cardiac death, death according to stroke) among patients CVD within 10-years follow-up.

Material and methods: Overall 1002 in-patients with CVD were included. IL-6 protein level was determined by electrochemiluminescence immunoassay (fasting, between 7 and 8 a.m.). Genetic analyses were carried out by single specific primer-polymerase chain reaction.

Results: In survival analyses, IL-6 protein levels of ≥6.4 pg/mL (log-rank test: p = 0.034; cox regression: p = 0.032, hazard ratio = 1.29) and CC genotype of rs1800795 (log-rank test: p < 0.001, cox regression: p < 0.001, hazard ratio = 1.72) and AA genotype of rs180797 (log-rank test: p = 0.002, cox regression: p < 0.001, hazard ratio = 1.62) were associated with a poorer CV prognosis considering combined CV endpoint.

Conclusion: This study was the first to investigate both elevated IL-6 levels and genetic variants for their prognostic value for adverse CV outcomes in CVD patients within the 10-year follow-up period.