Interleukin-6 (IL-6) is a cytokine with a complex function that is described as both pro- and anti-inflammatory. One factor that influences its function is the rs2228145 A/C single nucleotide polymorphism (SNP) of the IL-6 receptor (IL6R) gene. C allele carriers have a decreased inflammatory response and decreased prevalence of ischemic heart disease. The aim of the study was to investigate the association of the rs2228145 SNP of the IL6R gene with long-term total mortality in patients with ST-elevation myocardial infarction (STEMI) treated invasively.
We analyzed the data of consecutive patients with ST elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). Genotyping was performed with the TaqMan method. The analyzed end-point was total long-term mortality (median: 2875 days).
The registry comprised 553 patients (mean age: 62.4 ±11.9 years; 25.6% females, n = 142; TIMI 3 obtained in 91.7% of patients, n = 507). No significant differences in baseline characteristics were found between the genotypes. During long-term follow-up 171 (30.9%) patients died. There was non-significantly higher mortality in the rs2228145 AA homozygotes compared to C allele carriers (OR = 1.34, 95% CI: 0.93-1.93, p = 0.1).
The rs2228145 polymorphism of IL6R was not significantly associated with long-term mortality after STEMI. However, AA homozygotes (high-risk genotype for ischemic heart disease) showed a trend towards adverse outcome compared to C allele carriers. The observed trend is promising, but it requires independent replication studies.