Warfarin anticoagulation intensity in specialist-based and in computer-assisted dosing practice

Area of Science:

• Pharmacology
• Clinical Medicine
• Health Informatics

Background:

• Oral anticoagulation (OA) with vitamin K antagonists requires precise international normalized ratio (INR) control for efficacy and safety.
• Maintaining INR within target ranges is crucial for patients with atrial fibrillation (AF), venous thromboembolism (VTE), and prosthetic heart valves (PHV).

Purpose of the Study:

• To evaluate the quality of software-assisted warfarin dosing in 2006.
• To compare current software-assisted dosing with previous cardiologist-based dosing from 1992.
• To assess improvements in anticoagulation control over 14 years.

Main Methods:

• Retrospective analysis of 941 patients on stable OA in 2006 using software-assisted dosing.
• Comparison with 241 comparable patients from a 1992 study using cardiologist-based dosing.
• Assessment of time within therapeutic INR range and frequency of extreme INR values.

Main Results:

• Time within target INR range increased significantly across all groups: AF (46% to 81%), VTE (62% to 84%), and PHV (40% to 64%).
• Incidence of INR < 1.5 decreased from 7% to 1% (P < 0.0001).
• Incidence of INR > 4.0 decreased from 2.8% to 0.4% (P < 0.0001).

Conclusions:

• Current software-assisted warfarin dosing achieves INR targets more effectively than previous cardiologist-based methods.
• Extreme low and high INR values are less frequent with software-assisted dosing.
• Improved anticoagulation control suggests enhanced efficacy and safety in OA management.