Changes in CHA2DS2-VASc score and risk of ischemic stroke among patients with atrial fibrillation

Abstract

Aims: The CHA2DS2-VASc score is fundamental to stroke risk assessment in atrial fibrillation. However, stroke-related risk factors can be modified later in life. This study aimed to assess the association of changes in CHA2DS2-VASc score over time (Delta CHA2DS2-VASc score) with the risk of ischemic stroke. Materials and methods: This is an observational analysis of 1127 atrial fibrillation patients previously enrolled in the MISOAC-AF trial. After a median 2.6-year follow-up period, baseline and follow-up CHA2DS2-VASc scores were used to extract the Delta CHA2DS2-VASc score. The stroke predicting accuracies of the baseline, follow-up, and Delta CHA2DS2-VASc scores were assessed through regression analyses. Results: The mean baseline, follow-up, and Delta CHA2DS2-VASc scores were 4.2, 4.8, and 0.6 respectively. Ischemic stroke occurred in 54 (4.4%) patients, of which 83.3% had a Delta CHA2DS2-VASc score ≥1, contrary to 40.1% of the stroke-free group. The stroke risk per 1-point increase of the CHA2DS2-VASc score was not significantly associated with the baseline score (aHR=1.14; 95%CI: 0.93-1.41; p=0.201), whereas a significant association was observed with the follow-up (aHR=2.58; 95% CI: 2.07-3.21; p<0.001) and Delta (aHR=4.56; 95%CI: 3.50-5.94; p<0.001) scores. C-index assessment indicated that follow-up and Delta CHA2DS2-VASc scores were more potent predictors of ischemic stroke compared to baseline. Conclusion: In atrial fibrillation patients, changes in CHA2DS2-VASc score over time were associated with the incidence of stroke. The improved predictability of follow-up and Delta CHA2DS2-VASc scores indicates that stroke risk is not a static parameter. Trial registration: This is an observational, post-hoc analysis of the MISOAC-AF randomized controlled trial, registered on ClinicalTrials.gov (identifier: NCT02941978; registered: October 21, 2016).