Warfarin control in Hong Kong clinical practice: a single-centre observational study

Introduction: Time in therapeutic range (TTR) assesses the safety and effectiveness of warfarin therapy using the international normalised ratio. This study investigated the TTR in Hong Kong patients using both European and Japanese therapeutic ranges and patients' economic and clinical outcomes. Predictors of poor warfarin control and patient knowledge concerning warfarin therapy were assessed. Methods: A 5-month observational study with retrospective and prospective components was conducted in the Prince of Wales Hospital. The study examined electronic patient records of patients who received warfarin for at least 1 year during the period from January 2010 to August 2015. Patient knowledge was assessed via phone interview using the Oral Anticoagulation Knowledge (OAK) test. Results: In total, 259 patients were included; 174 completed the OAK test. The calculated mean TTR was 40.2 +/- 17.1% (European therapeutic range), compared with 49.1 +/- 16.1% (Japanese therapeutic range) [P