Is there an optimal time to transition to low dose direct oral anticoagulants?

Abstract Background: Prophylactic-dose or low-dose apixaban and rivaroxaban have been studied in randomized controlled trials for the extended prevention of venous thromboembolism (VTE) after 6 months of treatment with therapeutic anticoagulation. However, the optimal timing of dose adjustment has not been fully explored, and the rationale for a precise transition at the 6-month mark is lacking. Aim: Evaluate the clinical outcomes and demographic differences between transition to low-dose DOAC before or after the previously studied 6-month timeframe. Methods: Consecutive patients with VTE were identified using the Mayo Clinic VTE Registry from March 1st, 2013 to December 31st, 2021. Patients with recurrent VTE or bleeding during the first 3 months were excluded. Patients were followed prospectively for outcomes of VTE recurrence, major bleeding, and clinically relevant non major bleeding (CRNMB), either in person or by survey. After completion of anticoagulation treatment for 3 months, the cohort of patients continuing anticoagulation with eventual transition to low-dose rivaroxaban or apixaban were evaluated. Results: A total of 466 patients were included with 167 (36%) undergoing transition to low dose prior to 6 months and 299 (64%) after 6 months of treatment. The average time to low-dose transition in the total population was 7.8 months (5.9, 3.0-55.8). The early transition group had less PE (82 versus 191, p=0.017) and significantly fewer patients with concurrent DVT and PE (32 versus 101, p=0.004). There was nearly equal representation of cancer in the two groups (34.7% versus 35.8%). Evaluation of clinical outcomes from transition time forward in the groupings before and after six months revealed no significant differences (VTE recurrence p=0.233, MB p=0.114, CRNMB p=0.745). Conclusions: This real-world patient population demonstrates that anticoagulant prescribers transition to low-dose DOACs ahead of the historically studied 6-month time point. The results of this study do not indicate a significant difference in clinical outcomes of VTE recurrence or bleeding complications based on time of transition to low-dose DOACs either before or after 6 months.