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Warfarin dose management affects INR control
A J Rose1, A Ozonoff, D R Berlowitz
1Center for Health Quality, Outcomes, and Economic Research, Bedford VA Medical Center, Bedford, MA 01730, USA. adamrose@bu.edu
Journal of Thrombosis and Haemostasis : JTH
|November 6, 2008
Summary
Optimizing warfarin dose management improves International Normalized Ratio (INR) control. Adjusting warfarin dosage based on specific INR thresholds, rather than current practices, significantly enhances time in therapeutic range (TTR).
Area of Science:
- Pharmacology
- Clinical Pharmacy
- Internal Medicine
Background:
- Warfarin dose management's impact on therapeutic International Normalized Ratio (INR) range (TTR) is not well understood.
- Effective INR management is crucial for preventing thromboembolic events and bleeding complications.
Purpose of the Study:
- To quantify how warfarin dose management strategies influence TTR.
- To define an optimal warfarin dose management strategy for improved INR control.
Main Methods:
- A cohort of 3961 patients on warfarin from 94 clinics was analyzed.
- A predictive model for warfarin dose changes was developed and validated.
- Observed minus expected (O-E) scores were used to assess adherence to predicted dosing adjustments and their correlation with TTR.
Main Results:
- Patients with dose changes closest to predicted values achieved the highest mean TTR (70.1%).
- Deviations from predicted dose changes were associated with significantly lower TTR (65.8% and 62.0%).
- Current average dosing adjustments (INR ≤1.8/≥3.2) yielded 68% TTR, whereas optimal adjustments (INR ≤1.7/≥3.3) predicted 74% TTR.
Conclusions:
- Warfarin dose management significantly impacts INR control.
- Adjusting warfarin dosage when INR is ≤1.7 or ≥3.3 may substantially improve TTR.
- Further validation through a randomized controlled trial is recommended to confirm these findings.
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