Prediction of Stroke Risk in Patients with Atrial Fibrillation: Comorbidities vs Temporal AF Behavior

BackgroundThere are controversies about whether atrial fibrillation (AF) type, paroxysmal (PaAF) vs persistent (PeAF), affects stroke risk. The type of AF is still not included in most risk stratification tools. ObjectiveWe aim to assess differences in stroke outcomes between PaAF and PeAF patients in both low- and high-CHA2DS2-VASc groups. MethodsWe conducted an epidemiological study of all patients admitted to Tulane Medical Center with the diagnosis of AF from January 2010 to March 2020. Data were extracted from the regional US electronic medical records database, Research Action for Health Network (REACHnet), for all patients aged 18 years or older with a diagnosis of AF. Patients were divided into four groups: a low CHA2DS2-VASc score was defined as CHA2DS2-VASc < 2 in women and CHA2DS2-VASc < 1 in men. PeAF was defined as a patient with at least one episode of AF lasting 7 days or more. PaAF was defined as a patient with AF with no episode lasting more than 7 days. The outcome of the study was an ischemic stroke event or a transient ischemic attack that occurred after the diagnosis of AF. Kaplan-Meier curves and the log-rank test were used to compare the study outcomes across all four groups. Multivariable Cox regression was performed to adjust for the use of anticoagulants. ResultsA total of 1,079 patients were included in the study. 576 patients had PaAF and high CHA2DS2-VASc, 215 had PaAF and low CHA2DS2-VASc, 214 had PeAF and high CHA2DS2-VASc, and 74 patients were PeAF, and low CHA2DS2-VASc. Patients were followed up over 5 years. Based on the Log-rank test, there were significant differences among the four groups (p < 0.001). After adjusting for anticoagulants, patients with high CHA2DS2-VASc appeared to have more strokes on follow-up than patients with low CHA2DS2-VASc, independent of AF type and anticoagulation prescription. For the Cox model, when the PaAF High CHA2DS2-VASc group was used as the reference, both low CHA2DS2-VASc groups, PaAF (0.032 [0.012-0.081], p < 0.001) and PeAF (0.032 [0.008-0.135], p < 0.001), had a lower risk of stroke. However, there was no difference in stroke when the reference group was compared to high CHA2DS2-VASc, PeAF (1.169 [0.866 - 1.576], p=0.308). ConclusionIn our database, the CHA2DS2-VASc score remained superior to the type of AF when predicting stroke outcome. Type of AF did not affect stroke outcome even after adjusting for CHA2DS2-VASc and for anticoagulation prescription.