Prognostic value of interleukin-6 in atrial fibrillation: A cohort study and meta-analysis

OBJECTIVE: The prognostic value of interleukin-6 (IL-6) in patients with atrial fibrillation (AF) has not been fully elucidated. Therefore, we conducted a cohort study and a meta-analysis to assess the predictive value of IL-6 for stroke and mortality in patients with AF. METHODS: A cohort study was performed in newly diagnosed non-valvular patients with AF. A total of 217 patients with AF were followed up for a mean of 27 months. A multivariate Cox regression analysis was used to evaluate the association between IL-6 and stroke/all-cause mortality. The incremental value was also assessed by adding IL-6 to the CHA2DS2-VASc score. Besides, a meta-analysis of all reported cohort studies and our cohort study was conducted to validate the association of circulating IL-6 and stroke/mortality in patients with AF. RESULTS: Our cohort study showed that elevated plasma level of IL-6 was an independent risk factor for predicting stroke [hazard ratio (HR)=3.81; 95% confidence interval (CI), 1.11-13.05; p=0.033] and all-cause mortality (HR=3.11; 95% CI, 1.25-7.72; p=0.015) in patients with AF. Adding IL-6 levels to CHA2DS2-VASc score showed limited improvement of the predictive power for stroke [area under curve (AUC) from 0.81 to 0.88, p=0.006]. Meta-analysis confirmed that increased circulating level of IL-6 was significantly associated with increased risk of stroke (pooled HR=1.97; 95% CI, 1.22-3.17; p=0.006) and all-cause mortality (pooled HR=2.73; 95% CI, 2.29-3.25; p<0.001). CONCLUSION: Increased circulating level of IL-6 was significantly associated with greater risk of stroke and all-cause mortality in patients with AF. Adding IL-6 biomarker to the CHA2DS2-VASc score may help to determine the management of AF treatment.