Sex and Gender Differences in Thromboprophylactic Treatment of Patients With Atrial Fibrillation After the Introduction of Non-Vitamin K Oral Anticoagulants.

To examine sex differences in thromboprophylaxis in patients with atrial fibrillation before and after the introduction of non-vitamin K oral anticoagulants, we performed a cross-sectional registry study based on anonymized individual-level patient data of all individuals with a diagnosis of nonvalvular atrial fibrillation (International Classification of Diseases, Tenth Revision code I48) in the region of Stockholm, Sweden (2.2 million inhabitants), in 2011 and 2015, respectively. Thromboprophylaxis improved considerably during the period. During 2007 to 2011, 23,198 men and 18,504 women had an atrial fibrillation diagnosis. In 2011, more men than women (53% men vs 48% women) received oral anticoagulants (almost exclusively warfarin) and more women received aspirin only (35% women vs 30% men), whereas there was no sex difference for no thromboprophylaxis (17%). During 2011 to 2015, 27,237 men and 20,461 women had a diagnosis of atrial fibrillation. Compared with the earlier time period, a higher proportion used oral anticoagulants (71% women vs 70% men), but fewer women ≥80 years received anticoagulants (67% women vs 72% men), more women received aspirin (15% women vs 13% men), and fewer women had no thromboprophylaxis (15% women vs 17% men). Patients with co-morbidities potentially complicating oral anticoagulant use used more oral anticoagulant in 2015 compared with 2011. The sex differences observed in 2011 with fewer women using oral anticoagulants had disappeared in 2015 except in women 80 years and older and in patients with complicated co-morbidity.