Plasma Level of Interferon-γ Predicts the Prognosis in Patients With New-Onset Atrial Fibrillation

Background Patients with atrial fibrillation are at increased risk of stroke and mortality. It is not clear if inflammatory biomarkers are associated with stroke and mortality in patients with atrial fibrillation. We aimed to evaluate the predictive value of three inflammatory biomarkers (interleukin [IL]-9, IL-10, and interferon [IFN]-gamma) for stroke and mortality in atrial fibrillation. Method A total of 232 patients with new-onset atrial fibrillation were enrolled and 217 patients were completely followed-up. Peripheral plasma concentrations of cytokines (IL-9, IL-10, and IFN-gamma) were measured using Luminex xMAP assays. The association between dichotomous groups of cytokines and outcomes were evaluated by a Cox proportional hazards model. The incremental value of inflammatory biomarkers, in addition to the CHA2DS2-VASc score, was also assessed. Results Patients were followed-up for a median duration of 27 (interquartile range [IQR], 23-30) months. The elevated plasma level of IFN-gamma was an independent risk factor for stroke (hazard ratio [HR], 4.02 [IQR, 1.06-15.34]; p=0.042) and all-cause mortality (HR, 3.93 [IQR, 1.43-10.78]; p=0.008) in patients with atrial fibrillation. Adding high IFN-gamma to the CHA2DS2-VASc score showed improvement in discrimination and reclassification prediction for stroke and mortality. However, IL-9 and IL-10 had no statistically significant association with stroke and all-cause mortality in patients with atrial fibrillation. Conclusions In this "real-world" cohort of patients with atrial fibrillation, we have shown for the first time that plasma levels of IFN-gamma could provide incremental prognostic value supplementary to that obtained from the CHA2DS2-VASc scores for predicting of stroke and all-cause mortality.