Women with nonvalvular AF less likely to receive oral anticoagulation, at higher risk of stroke

Female patients nonvalvular atrial fibrillation (AF) are less often prescribed guideline-recommended oral anticoagulation at the emergency department (ED), which in turn contributes to an increased stroke risk at 1 year regardless of discharge status, a study has found.

The analysis included 28,886 patients (44 percent women) aged >20 years who presented to the ED with incident nonvalvular AF. Researchers looked at the use of and adherence to oral anticoagulants at 1 year using the proportion of days covered for direct oral anticoagulants and time in therapeutic range for warfarin.

Compared with men, women were older (mean 74 vs 66 years), had a higher CHA₂DS₂-VASc score (median 4 vs 2), and more likely to have a history of heart failure, hypertension, and prior stroke/transient ischaemic attack. Men, on the other hand, were more likely to present with diabetes, peripheral arterial disease, and prior myocardial infarction. In terms of baseline medication, women were more often taking angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, beta blockers, calcium channel blockers.

The rate of oral anticoagulant use was 5 percent lower in women with a guideline indication than that in men who were discharged home (adjusted hazard ratio [aHR] 0.95, 95 percent confidence interval [CI], 0.91–0.99). Meanwhile, there was no significant between-group difference seen among admitted patients (aHR, 1.00, 95 percent CI, 0.96–1.05).

Among participants who were prescribed anticoagulation, women exhibited higher adherence to direct oral anticoagulants (≥80 percent proportion of days covered) than men (discharged: 77.7 percent vs 74.0 percent; admitted: 80.0 percent vs 76.7 percent; adjusted odds ratio, 1.15, 95 percent CI, 1.02–1.29). More than half of the patients showed poor warfarin control (time in therapeutic range <65 percent), regardless of discharge status.

Outcomes such as heart failure and all-cause mortality at 1 year were similar in women and men, except for stroke, the risk of which was 48-percent higher in women (aHR, 1.48, 95 percent CI, 1.14–1.92).

The findings highlight the importance of diagnosing and treating AF patients based on thromboembolic risk, irrespective of sex.