More Severe Strokes for Women With Atrial Fibrillation

Study Questions:

Does sex affect ischemic stroke severity in patients with atrial fibrillation (AF)?

Methods:

The authors used data from the Austrian Stroke Unit Registry to determine what factors influence stroke severity in AF. The registry is government funded and data collection is done by stroke neurologists at 38 participating centers. AF, paroxysmal or persistent, was diagnosed by a physician or by patient self-report. Stroke severity was measured by the National Institutes of Health Stroke Scale (NIHSS), with higher scores indicating more severe strokes. Patients with transient ischemic attacks were excluded from the study. The relationship between stroke severity and covariates was modeled by multivariate logistic regression.

Results:

There were 74,435 ischemic stroke patients in the registry between March 2003 and January 2016. After excluding patients with missing data, 63,563 patients were included in the analyses. AF was present in 29.8% of the cohort and strokes in patients with AF were more severe than strokes in patients without AF. When sex differences were examined, women with AF had more severe strokes (median NIHSS, 9; interquartile range [IQR], 4-17) than men with AF (median NIHSS, 6; IQR, 3-13). This sex difference in stroke severity was independent of age and not present in strokes not due to AF.

Conclusions:

The authors concluded that women with AF have more severe strokes than men with AF.

Perspective:

AF is associated with more severe ischemic strokes than other stroke etiologies, and women tend to have more severe ischemic strokes than men. This is the first study to show that women with AF have more severe strokes than men with AF. The mechanism underlying this finding is unclear. A possible explanation is anticoagulation use. Women with AF tend to be less effectively anticoagulated than men, and that could account for the difference in stroke severity. Unfortunately, the authors do not have data regarding anticoagulation use. Other possible explanations include effects of sex hormones or women’s smaller blood vessel diameter leading to emboli causing more proximal occlusions, and therefore, more severe strokes. At this point, these conclusions should be considered hypothesis generating, and future work should aim to replicate the findings and seek to identify mechanisms underlying the sex differences in severity of AF-related stroke.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Embolism, Ischemia, Ischemic Attack, Transient, Sex Characteristics, Stroke, Vascular Diseases, Women


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