Proportion of Patients on Warfarin Therapy Who Are Eligible for Conversion to a Direct Oral Anticoagulant in the Setting of COVID-19

Abstract

Background: Warfarin, a commonly prescribed anticoagulant, requires frequent lab monitoring. Lab monitoring puts patients at risk of COVID-19 exposure and diverts medical resources away from health care systems. Direct oral anticoagulants (DOACs) do not require routine therapeutic monitoring and are indicated first line for nonvalvular atrial fibrillation (NVAF) stroke prevention and venous thromboembolism (VTE) prevention/treatment. Objective: The purpose of the study was to determine the proportion of patients who qualify for DOACs and assess for predictors of qualification. Methods: This cross-sectional study investigated patients on warfarin managed by Michigan Medicine Anticoagulation Service. Direct oral anticoagulant eligibility criteria were established using apixaban, dabigatran, and rivaroxaban package inserts. Patient eligibility was determined through chart review. The primary outcome was the proportion of patients who qualify for DOACs based on clinical factors. Predictors of DOAC qualification were assessed. Results: This study included 3205 patients and found 51.8% ( n = 1661) of patients qualified for DOACs. Qualifying patients were older (71.9 vs 59.4 years, P < 0.0001) with a higher CHA2DS2 VASc (3.7 vs 3.4, P < 0.0007). The primary disqualifying factor was extreme weight, high and low. Accounting for a patient’s sex and referral source, age > 65 (odds ratio [OR] = 1.9, P < 0.0001) and NVAF indication (OR = 5.6, P < 0.0001) were significant predictors for DOAC qualification. Conclusion and Relevance: Approximately 52% of patients on warfarin were eligible for DOACs. This presents an opportunity to reduce patient exposure to health care settings and health care utilization in the setting of COVID-19. Increased costs of DOACs need to be assessed.