Aims: To investigate sex-specific temporal trends in the initiation of oral anticoagulant (OAC) therapy among patients diagnosed with atrial fibrillation (AF) in Finland between 2007 and 2018.

Methods: The registry-linkage Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) Study included all patients with incident AF in Finland from 2007 to 2018. The primary outcome was the initiation of any OAC therapy.

Results: We identified 229,565 patients with new-onset AF (50.0% women; mean age 72.7 years). The initiation of OAC therapy increased continuously during the observation period. While women were more likely to receive OAC therapy overall, after adjusting for age, stroke risk factors and other confounding factors, female sex was associated with a marginally lower initiation of OACs (unadjusted and adjusted hazard ratios comparing women to men: 1.08 (1.07-1.10) and 0.97 (0.96-0.98), respectively). Importantly, the gender disparities in OAC use attenuated and reached parity by the end of the observation period. Furthermore, when only patients eligible for OAC therapy according to the contemporary guidelines were included in the analyses, the gender inequalities in OAC initiation appeared minimal. Implementation of direct OACs for stroke prevention was slightly slower among women.

Conclusion: This nationwide retrospective cohort study covering all patients with incident AF in Finland from 2007 to 2018 observed that although female sex was initially associated with a lower initiation of OAC therapy, the sex-related disparities resolved over the course of the study period.