Evaluating the Effectiveness of a Pharmacist-Driven Warfarin Consult Service Versus Physician Management in a Tertiary Community Hospital

Background: The use of warfarin is complicated by a narrow therapeutic window, requiring close monitoring to prevent serious adverse events. Literature has shown that pharmacist-led warfarin management improves patient outcomes and decreases hospitalization length of stay. This study assessed the impact of the recently implemented pharmacist-driven warfarin consult service at 3 hospitals within the Cleveland Clinic Health System. Methods: This was a retrospective, multi-centered study which included 64 adult patients admitted to Cleveland Clinic Hospitals between June 1, 2023, and July 31, 2024 who received at least 3 doses of warfarin. Exclusion criteria included an elevated international normalized ratio (INR) upon admission, argatroban use, active cancer, or warfarin ordered by both managing services. Results: The primary outcome, rate of supratherapeutic INR values, did not significantly differ between groups (P = .84). In addition, the secondary outcomes including rate of subtherapeutic INRs, INR ≥0.7 within 24 hours, therapeutic INR at discharge, and major bleeding showed no significant difference. However, pharmacists were twice as likely to order an initial starting dose of <5 mg compared to physicians (62.5% vs 31.3%). In addition, physician-managed patients were observed more frequently for the INR ≥0.7 within 24 hours (11 vs 4 events). Conclusion: Overall, there was not a significant difference found in patient outcomes when comparing pharmacist versus physician warfarin management. Future studies with a larger sample size are needed to explore the potential differences in dosing regimens and its effect on the rate of significant INR elevations.