Background and objectives
Female sex is associated with higher stroke rates in atrial fibrillation (AF) after adjustment for other CHA2DS2-VASc factors. This study aimed to describe sex differences in age and cardiovascular care to examine their relationship with stroke risk in AF.
Methods
Population-based cohort study using administrative data sets of people aged ≥66 years diagnosed with atrial fibrillation (AF) in Ontario between 2007 and 2019. Cause-specific hazard regression was used to estimate the adjusted hazard ratio (HR). for female-associated stroke over a 2-year follow-up period.
Model 1 included CHA2DS2-VASc factors, with modeled age 66 to 74 vs. ≥75 years. Model 2 treated age as a continuous variable and included an age-sex interaction term. Model 3 also took into account multimorbidity and markers of cardiovascular care.
Results
The cohort consisted of 354,254 people with atrial fibrillation (AF) (mean age 78 years, 49.2% women).
Women were more likely to be diagnosed in emergency departments and less likely to receive cardiology evaluations, statins , or LDL-C testing, with LDL-C levels higher among women than men.
In Model 1, the adjusted HR for stroke associated with female sex was 1.27 (95% confidence interval: 1.21-1.32).
Model 2 revealed a significant interaction between age and sex, such that female sex was only associated with an increased risk of stroke at age >70 years.
Adjustment for markers of cardiovascular care and multimorbidity further decreased HR, such that female sex was not associated with an increased risk of stroke at age ≤80 years.
Conclusion Female patients with atrial fibrillation (AF) are more likely to be diagnosed in the emergency department than men, less likely to be evaluated by cardiologists, less likely to receive statins, have LDL-C testing, and more likely to have low higher systolic BP and LDL-C levels. The sex-specific difference in stroke risk was attenuated after accounting for indicators of cardiovascular care. These data highlight the need to reduce sex-based inequalities in cardiovascular care in older people with AF, as they may underlie the increased risk of stroke observed among female patients. Advanced age and inequalities in cardiovascular care may partly explain the higher rates of stroke in women with AF. |
Comments
Inequalities in cardiovascular care are putting older women’s heart health at risk
An increased risk of stroke among women with atrial fibrillation may be related to sex-based disparities in cardiovascular care, according to a new study from Women’s College Hospital, the Peter Munk Cardiac Center (PMCC) of the University Health Network (UHN). and ICES.
Atrial fibrillation ( AF) is a common type of irregular heart rhythm that is associated with an increased risk of stroke: after age 40, one in four strokes is caused by AF. Previous studies have found that female sex (assigned at birth) is a risk factor for stroke associated with AF. Recent research has suggested that women are only at greater risk than men for AF if they have another factor that predisposes them to stroke (such as older age, hypertension, or diabetes).
The reasons for this increased risk of stroke in women have not been well examined. The authors hypothesized that this was because these risk factors were treated less well in older women, rather than because female sex intrinsically predisposed them to this increased risk.
The population-based cohort study, published in the European Heart Journal , analyzed the medical records of people aged 65 years and older with a recent diagnosis of AF in Ontario, Canada. The cohort included 354,254 people (49% women), with an average age of 78 years. The study was made possible by the Early Career Women’s Heart and Brain Health Chair and the National New Investigator Award from the Heart and Stroke Foundation of Canada.
"After taking into account the individual’s age and differences in cardiovascular care, the data show that the risk of stroke was similar between men and women under the age of eighty, but that female sex was an independent risk factor for starting at age eighty ," says lead author Hifza Buhari, a family medicine resident at the University of Toronto and Temerty’s former medical student at Women’s College Hospital. "Women tend to be diagnosed with atrial fibrillation at older ages and may not receive adequate follow-up or treatment to reduce their risk of stroke."
The data also shows that, compared to men:
Women were diagnosed more frequently in emergency departments (30% versus 25% for men)
Women received fewer appointments with the cardiologist, both in the year before (12% versus 17%) and after (31% versus 37%) the AF diagnosis.
Women were also less likely to have LDL-C testing and be treated with statins, despite having higher LDL-C levels and higher blood pressure than their male counterparts.
"Equalizing cardiovascular care for men and women is an important step toward healthier hearts and lives for all," says lead author Husam Abdel-Qadir, a cardiologist at Women’s College Hospital and Peter Munk Cardiac Centre, University Health Network, and a scientist at Women’s College Research. Institute, Ted Rogers Center for Heart Research and ICES. "By addressing sexual inequalities, we can increase the likelihood that each individual has the best chance at a heart-healthy future."
One limitation of the data is that the researchers were unable to account for variables such as race, type or severity of AF, and other clinical factors, which may have led to an underestimation of disparities in cardiovascular care that disproportionately affect to older women.
“This study is another reminder that heart disease and stroke are not male diseases . ” Although there is widespread recognition that women with AF have a higher risk of stroke than men, they receive less cardiovascular care, which has real consequences. These data emphasize that women, particularly older women, need adequate care to reduce the risk of these serious diseases,” says Dr. Abdel-Qadir.
