What Contributes to the Higher Stroke Risk in Women With AFib?
Female sex is associated with higher stroke rates among those with atrial fibrillation (AFib) after adjusting for other CHA2DS2-VASc risk factors, and older age and inequities in cardiovascular care may be contributing to these higher rates according to a population-based cohort study published Aug. 30 in the European Heart Journal.
Hifza Buhari, MSc, et al., examined data from a cohort of 354,254 individuals living in Ontario, Canada, who were ≥66 years old when they were diagnosed with AFib or atrial flutter between 2007 and 2019, to assess whether differences in age and preventive cardiovascular care contributed to the higher rates of stroke in women. The median age of the study cohort was 78 years and 49.2% were women. Exclusion criteria were a diagnosis of AFib in the previous five years to capture those with newly recognized AFib and valvular disease.
Results showed that women, compared with men, were more likely to be first diagnosed with AFib in the emergency department (30.4% vs. 24.7%), were older at diagnosis (80 vs. 77 years), were less likely to receive assessment by a cardiologist (11.6% vs. 16.9% before and 30.7% vs. 36.9% after AFib diagnosis), as well as less likely to have testing for LDL-C levels or receive statin treatment despite having higher LDL-C levels.
Furthermore, using three different models, the researchers found that the adjusted hazard ratio for stroke associated with female sex was 1.27 (95% CI, 1.21-1.32), and that there was a significant age-sex interaction, with female sex only associated with increased stroke risk among those >70 years old. Notably, however, after adjusting for cardiovascular care markers and multimorbidity, female sex was not associated with an increased risk of stroke in women ≤80 years old.
"Our findings indicate that age modifies the association between sex and stroke in [AFib], with female sex being independently associated with higher risk in those aged >80 years, but not in younger people," write the authors. They note that after accounting for age and inequities in cardiovascular care, the risk of stroke is similar in women and men younger than 80 years. "These data highlight the need to reduce sex-based inequities in cardiovascular care in older people with [AFib], as they may underlie the higher stroke risk observed among female patients," they write.
Keywords: Atrial Fibrillation, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Stroke, Atrial Flutter, Heart Valve Diseases
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