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Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood
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Supra-therapeutic Anticoagulation with Warfarin: A Cross-sectional Study
Kannan Sridharan1, Rashed Al Banna2, Aysha Husain2,3
1Department of Pharmacology & Therapeutics, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Kingdom of Bahrain.
Current Drug Safety
|May 4, 2022
Summary
Elderly patients, higher HAS-BLED scores, and longer warfarin therapy increase supratherapeutic INR risk. Careful warfarin dosage adjustments are crucial, especially in these high-risk groups.
Area of Science:
- Pharmacology and Therapeutics
- Cardiovascular Medicine
- Clinical Pharmacy
Background:
- Limited studies exist on managing patients with supratherapeutic anticoagulation on warfarin.
- Understanding management strategies for bleeding and non-bleeding supratherapeutic PT-INR is crucial.
Purpose of the Study:
- To determine the prevalence of prolonged prothrombin time, international normalized ratio (PT-INR) in warfarin patients.
- To identify factors associated with supratherapeutic anticoagulation without bleeding.
- To analyze warfarin dosage modifications in response to supratherapeutic PT-INR.
Main Methods:
- A cross-sectional study included 144 patients on long-term warfarin with PT-INR > 3.2.
- Calculated Percent Time in Therapeutic Range (TTR) and defined anticoagulation control (good >65%, poor <65%) per NICE guidelines.
Main Results:
- Nearly 50% of patients had PT-INR between 3.2 and 3.9; average of 4 supratherapeutic readings.
- Elderly patients, longer warfarin duration, and higher HAS-BLED scores were linked to supratherapeutic INR.
- Lower TTR correlated with frequent PT-INR > 4, indicating poor anticoagulation control; significant dose modification variations noted.
Conclusions:
- Supratherapeutic INR (3.2-3.9) is common, particularly in elderly patients with higher HAS-BLED scores and prolonged warfarin use.
- Increased risk of supratherapeutic anticoagulation necessitates careful warfarin dose adjustments in identified high-risk populations.
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