Type of atrial fibrillation and outcomes in patients without oral anticoagulants

Background: The effect of type of atrial fibrillation (AF) on adverse outcomes in Chinese patients without oral anticoagulants (OAC) was controversial.

Hypothesis: The type of AF associated with adverse outcomes in Chinese patients without OAC.

Methods: A total of 1358 AF patients without OAC from a multicenter, prospective, observational study was included for analysis. Univariable and multivariable Cox regression models were utilized. Net reclassification improvement analysis was performed for the assessment of risk prediction models.

Results: There were 896(66%) patients enrolled with non-paroxysmal AF (NPAF) and 462(34%) with paroxysmal AF (PAF). The median age was 70.9 ± 12.6 years, and 682 patients (50.2%) were female. During 1 year of follow-up, 215(16.4%) patients died, and 107 (8.1%) patients experienced thromboembolic events. Compared with the PAF group, NPAF group had a notably higher incidence of all-cause mortality (20.2% vs. 9.4%, p < .001), thromboembolism (10.5% vs. 3.8%, p < .001). After multivariable adjustment, NPAF was a strong predictor of thromboembolism (HR 2.594, 95%CI 1.534-4.386; p < .001), all-cause death (HR 1.648, 95%CI 1.153-2.355; p = .006). Net reclassification improvement analysis indicated that the addition of NPAF to the CHA₂ DS₂ -VASc score allowed an improvement of 0.37 in risk prediction for thromboembolic events (95% CI 0.21-0.53; p < .001).

Conclusions: In Chinese AF patients who were not on OAC, NPAF was an independent predictor of thromboembolism and mortality. The addition of NPAF to the CHA₂ DS₂ -VASc score allowed an improvement in the accuracy of the prediction of thromboembolic events.