Give equal consideration to gender when giving blood thinners in atrial fibrillation, research says

Removal of gender from clinical risk scoring could simplify who should be offered life-saving blood thinners in patients with a common heart rhythm condition.

Women with an irregular heart rhythm called atrial fibrillation have a lower rate of death, stroke and blood clots compared to men, according to a new study.

The paper published in the European Heart Journal upends the current thinking on the impact that gender has on clinical outcomes in the context of atrial fibrillation.

In a large observational study conducted by the University of Birmingham involving National Institute for Health and Care Research (NIHR) Birmingham Biomedical Research Centre (BRC) researchers, 78,852 contemporary patients with atrial fibrillation (28,590 women and 50,262 men) were analysed to examine whether female gender should contribute to decision-making on the prescription of anticoagulants, as currently done in routine clinical practice. The study specifically excluded patients with a prior stroke or age over 75 years, where there is already a clear indication for anticoagulation regardless of gender.

“Removing gender from clinical risk scores could streamline risk stratification without compromising accuracy, and contribute to equality in care.”

Dr Asgher Champsi, co-author

Despite being considered at higher risk in historical research, women in this study using electronic health records from primary care in the UK were less likely to die, have a stroke or major blood clot than men, driven mainly by the lower rates of death in women. This was after accounting for the substantial differences between women and men, including age and other health conditions. There was no difference in the rates of stroke and arterial blood clots, or vascular dementia, when comparing women and men during an average of 5 years of follow-up.

The study also looked at the most common stroke risk tool used globally, the CHA₂DS₂-VASc score and found it only modestly predicted which patients would go on to have an adverse outcome. The risk score without gender (CHA₂DS₂-VA) had slightly better precision, although remained relatively limited.

The paper addresses a key issue on the practical use of oral anticoagulation to prevent strokes and other blood clots in patients with AF. The findings contribute to the growing evidence to avoid consideration of the patient’s gender when offering this core and life-saving component of AF management, in line with the new 2024 European Society of Cardiology (ESC) guidelines presented at the ESC Congress in London*.

Dr Asgher Champsi, NIHR Birmingham BRC clinical research fellow at the University of Birmingham and co-first author of the paper said: “This research questions whether gender should be used to make decisions on the prevention of stroke, blood clots and death in patients with atrial fibrillation, an increasingly common heart condition. Removing gender from clinical risk scores could streamline risk stratification without compromising accuracy, and contribute to equality in care.”

Dipak Kotecha, Professor of Cardiology at the University of Birmingham and co-theme lead of the NIHR Birmingham BRC Thrombo-inflammation research theme, added:

“Healthcare professionals and patients need to be aware of the poor performance of available risk scores. A personalised approach to decision-making on oral anticoagulation is critical to improve outcomes for patients with atrial fibrillation (and reduce the huge burden of health and social care costs). Rather than gender, this includes a broader range of factors that can lead to blood clots beyond conventional risk scores.”