Factors influencing oral anticoagulant use in patients newly diagnosed with atrial fibrillation

Background: We investigated factors that influenced oral anticoagulant (OAC) initiation and choice in Australian general practice patients newly diagnosed with AF.

Methods: Using an Australian nationally representative general practice dataset, MedicineInsight, we identified patients newly diagnosed with AF between January 2009 and April 2019. Logistic regression analyses were used to examine factors associated with OAC initiation and choice.

Results: A total of 63 212 patients with AF (53.7% males, mean age 72.4 years) were identified. Nearly two-thirds of these patients (40 854 [64.6%]) were initiated on an OAC, at a median time of 6 days after the documented diagnosis date. The proportion of patients who were initiated an OAC increased from 44.8% in 2009 to 72.2% in 2019 (P < .001). High risk of stroke (CHA₂DS₂-VASc, adjusted odds ratio (AOR), 4.39 [95% CI, 3.99-4.83]), low risk of bleeding (ORBIT, AOR, 1.87 [95% CI, 1.72- 2.03]), not having a recorded history of dementia (AOR, 1.81 [95% CI, 1.65-1.98]) and male sex (AOR, 1.29 [95% CI, 1.22-1.35]) were independently associated with OAC initiation. Direct-acting oral anticoagulant (DOAC) use increased from 11.9% in 2011 to 94.0% of all OAC initiations in April 2019 (P < .001).

Conclusions: The proportion of newly diagnosed patients with AF initiated on OAC increased markedly following the introduction of the DOACs. Of those initiated, 9 in 10 were receiving a DOAC at the end of the study period. There is potential underuse in women and individuals with dementia.