Fixed dose versus 3-day loading dose warfarin initiation in atrial fibrillation: effects on INR stabilization and time in the therapeutic range

The choice between fixed-dose and loading-dose warfarin initiation strategies does not independently influence long-term anticoagulation control. Instead, time to initial INR stabilization is the strongest predictor of TTR quality over 12 months. Clinical efforts should prioritize early and intensive INR monitoring in settings without genotype-guided dosing, as both baseline characteristics and the ongoing clinical management likely determine anticoagulation outcomes.