Stroke risks in women vs men in Asian patients with atrial fibrillation: A temporal trend analysis and a comparison of the CHA2DS2-VASc and CHA2DS2-VA stroke risk stratification scores.

BACKGROUND

The 2024 European guidelines for atrial fibrillation (AF) recommended the use of the sex-less CHA2DS2-VASc score (ie, CHA2DS2-VA) for stroke risk assessment, but this has been less well-validated in Asian cohorts.

OBJECTIVE

We aimed to perform a temporal analysis of stroke risks in women vs men with AF in Taiwan and to compare the performance of CHA2DS2-VASc vs CHA2DS2-VA scores.

METHODS

We used Taiwan's National Health Database (2000-2021) to compare CHA2DS2-VASc and CHA2DS2-VA scores by 2-year intervals, assessing performance with net reclassification index, integrated discrimination improvement, and C-statistics.

RESULTS

We analyzed 495,569 newly diagnosed, non-anticoagulated patients with AF (44% women). Across calendar years, women consistently had higher ischemic stroke risks than men (incidence rate ratio [IRR] 1.13-1.26, all P < .05). Among those with CHA2DS2-VA scores of 0-1, women had a lower stroke risk (score 0: IRR 0.81; score 1: IRR 0.88, both P < .001). For scores 2-8, stroke risk was higher in women (IRR 1.04-1.11, all P < .05). CHA2DS2-VASc significantly outperformed CHA2DS2-VA in net reclassification index from 2000 to 2021 and in integrated discrimination improvement from 2000 to 2015. C-statistics were slightly higher for CHA2DS2-VASc from 2000 to 2013 (P < .05), but not significantly different after 2014 (P > .05), suggesting comparable performance of the 2 scores in more recent years.

CONCLUSION

Women with AF have a higher stroke risk than men only in high CHA2DS2-VA score categories, suggesting female sex is more likely to be a risk modifier of stroke in AF. Retaining the female sex as a component of the CHA2DS2-VASc score may improve the net reclassification for stroke events in Asian patients with AF.