Feasibility of Warfarin Anticoagulation Management with a Patient Self-Testing Model in Korea

Abstract

Warfarin is the main oral anticoagulant effective for the prevention of stroke in patients with atrial fibrillation, and for the prevention and treatment of venous thromboembolism. It has a narrow therapeutic window of effectiveness and safety, which may lead to underuse. Accordingly, dose adjustments are mandatory for its effective and safe treatment, which depends on the time spent in the therapeutic International Normalized Ratio (INR) range (TTR). Hence, TTR is a key determinant of outcomes for patients receiving anticoagulation with warfarin. It is well known that lower rates of TTR in warfarin patients leads to an increased risk of bleeding or thromboembolic complications. Many studies have reported on the accuracy and precision of point-of-care (POC) devices when used by patients for INR monitoring on warfarin anticoagulation, as well as their good correlations with conventional plasma INR measurements within therapeutic ranges. Previous studies have indicated that a patient self-testing model may be superior to usual care or an anticoagulation clinic model in the quality of INR control. Recently, there has been increasing demand for high-quality warfarin management in Korea. Nevertheless, no domestic data have been reported on warfarin anticoagulation management using a patient self-testing (PST) model. Here, we describe our experiences with warfarin management using a PST model where the warfarin dose was adjusted by the anticoagulation clinic staff on the basis of a validated algorithm with the INR values self-tested by patients at home using capillary blood on the POC device CoaguChek-XS (Roche Diagnostics, Mannheim, Germany).