Background: Anticoagulation is commonly used to prevent and treat thromboembolic events. Warfarin is a cost-effective anticoagulant that requires close monitoring due to its narrow therapeutic index. Time in therapeutic range (TTR) is a measure of international normalized ratio (INR) control that can be used to measure effective anticoagulation in a patient population. Direct oral anticoagulants (DOACs) are effective anticoagulants with lower bleeding risk, fewer drug and diet interactions, and less frequent monitoring requirements compared to warfarin, but can be under-prescribed in low-income communities due to cost. Our quality improvement initiative aimed to increase the number of eligible patients transitioned from warfarin to DOAC therapy to optimize anticoagulation outcomes and access. We also hypothesized that improving access to DOAC therapy for eligible patients would enhance overall anticoagulation quality, as measured by TTR among patients remaining on warfarin, by allowing more focused monitoring and management.

Methods: A quality improvement initiative to transition eligible patients, without a first-line indication for warfarin, to DOACs was conducted. First-line indications for warfarin were defined as mechanical atrial valve replacement, mechanical mitral valve replacement, antiphospholipid syndrome, left ventricular thrombus, and valvular atrial fibrillation. Resident education, informational emails, educational flyers for staff, and increased discussions about anticoagulation were conducted in December 2024. A retrospective chart review was used to identify patients who had been prescribed warfarin therapy and had attended INR checks at our ambulatory care clinic from January 2024 to June 2025. Patient demographics, including age, sex, race, ethnicity, and insurance status, were collected both before and after our intervention. The number of patients transitioned to DOACs and the TTR of patients who were indicated for warfarin were measured pre-intervention (January 2024 to December 2024) and post-intervention (January 2025 to June 2025).

Results: In the pre-intervention group, 63 of 103 total patients were eligible to transition to DOACs compared to 21 of 60 patients in the post-intervention group. The number of eligible patients that were switched to DOAC therapy increased to 66.7% (n = 14/21) post-intervention from 15.8% (n=10/63) pre-intervention (p <0.001). In the pre-intervention group, 60% (n= 6/10) of patients who transitioned to DOACs were Black, and 40% (n=4/10) were Hispanic. In the post-intervention group, 57% (n=8/14) of patients transitioned were Hispanic, 36% (n = 5/14) were Black, and 7% (n= 1/14) were White. Among the patients transitioned to DOACs post-intervention, 71% (n = 10/14) were either uninsured or receiving Charity Care compared to 40% (n=4/10) pre-intervention.

Among patients with a first-line indication for warfarin, TTR increased to 64.3% (n=39) post-intervention from 54.3% (n=40) pre-intervention (p < 0.014). Within this population, the number of patients with increased bleeding risk, defined as one or more INR values > 4.5, decreased to 33.3% (n = 13/39) post-intervention from 70% (n = 28/40) pre-intervention (p <0.002).

Conclusions: The implementation of a quality improvement initiative offering cost-reduced DOAC therapy led to a statistically significant increase in the number of patients transitioned off of warfarin therapy. Subsequently, transitioning eligible patients from warfarin to DOAC therapy improved the overall effectiveness of anticoagulation and decreased bleeding risk among those who had a first-line indication for warfarin therapy, potentially due to reduced patient volume and improved physician resource allocation. Access to DOAC therapy was enhanced in racial minority and socioeconomically disadvantaged groups. Ongoing education of resident physicians to assess patients' eligibility and ability to transition to DOAC therapy, along with increased resource funding to support these transitions, should remain a priority in our warfarin clinic.

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2025
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