Gender and Carotid Artery Stenosis
To the Editor:
The recent study by Dick et al1 suggests that male patients with a severe carotid stenosis are at a higher risk of vascular events (mainly stroke) compared with women. I was surprised that the authors did not include atrial fibrillation as a potentially confounding variable in the multivariate analysis.
A community-based study reported that the prevalence of atrial fibrillation is greater in men compared with women.2 Atrial fibrillation is an important risk factor for stroke. If the cohort of men recruited for this study have a higher prevalence of atrial fibrillation, compared with women, this may explain their increased risk of vascular events.
We have read with interest the letter of Dr Epstein, and we agree that this limitation has to be considered. Unfortunately, we did not monitor patients for persistence or occurrence of atrial fibrillation during the study period, and as outlined by Dr Epstein, there may have been differences between the genders in the study population. However, looking at the huge frequencies of cardiovascular adverse events in males and females, it seems unlikely that the entire effect may be explained by the differences in atrial fibrillation, although admittedly we cannot rule out a confounding effect of atrial fibrillation.