Quality Assessment of Oral Anticoagulation by Time in Therapeutic Range in Patients with Venous Thromboembolism in Korea

The standard regimen with vitamin K antagonist (VKA) and lowmolecular-weight heparin (LMWH) was the main therapeutic option in patients with venous thromboembolisms (VTE) until the launch of direct oral anticoagulants (DOAC) in 2013 in South Korea. The ability of health-care provider to make appropriate dosage of VKA (e.g., warfarin) and follow-up decisions can have a major impact on therapeutic effectiveness and safety such as recurrent VTE and bleeding events, respectively. The quality of anticoagulation can be assessed by time in therapeutic range (TTR). A strong relationship between TTR and bleeding or thromboembolic rates has been observed across studies. However, TTR in real clinical practice was lower than 57% to 64% in clinical trials. The objective of this study was to investigate the quality of anticoagulation with TTR in patients with VTE in a single tertiary hospital in Korea.