Red cell distribution width as a novel predictor for clinical outcomes in patients with paroxysmal atrial fibrillation

Aims Elevated red cell distribution width (RDW) has been known to be associated with adverse long-term outcomes in patients with cardiovascular diseases. We aimed to evaluate relationship between RDW values and clinical outcomes in patients with paroxysmal atrial fibrillation (AF). Methods and results We analysed 567 patients who were newly diagnosed as paroxysmal AF. Clinical outcomes were analysed after median 4.8 (3.4-6.9) years follow-up. The composite clinical outcomes were defined as the composite of death, hospitalization due to heart failure, and new-onset stroke. Bleeding events were composed of major and minor bleeding. The relationship of RDW with clinical outcomes was assessed using continuous or categorical variables as quartiles: <12.8, 12.8-13.2, 13.3-13.8, and >= 13.9%. Patients with the highest RDW quartile were the oldest and had more frequent history of heart failure. CHA(2)DS(2)-VASc score was increased along with increasing RDW quartiles (1.75 +/- 1.48 vs. 1.77 +/- 1.63 vs. 1.87 +/- 1.61 vs. 2.33 +/- 1.65, P = 0.008). Incidence of new-onset stroke (log-rank P = 0.032), the composite clinical outcomes (log-rank P = 0.014), and bleeding events (log-rank P = 0.001) were increased as increasing RDW quartiles. Multivariate analysis identified that RDW was a significant predictor for new-onset stroke [adjusted hazard ratio (HR) 1.32, 95% confidence interval (CI) 1.06-1.65, P = 0.015], the composite clinical outcomes (adjusted HR 1.21, 95% CI 1.03-1.41, P = 0.017), and bleeding events (adjusted HR 1.36, 95% CI 1.13-1.64, P = 0.001). Conclusions RDW can be a new, useful, novel predictor of clinical and safety outcomes in patients with paroxysmal AF.