Optimal quality of vitamin K antagonist therapy in Japanese patients with venous thromboembolism

Abstract

Background: Vitamin K antagonist (VKA) remains an essential option for venous thromboembolism (VTE), although direct oral anticoagulants have become available. However, there is a paucity of data on the optimal intensity and quality of control for VKA in Japanese.

Methods: The COMMAND VTE Registry is a multicenter registry enrolling consecutive 3027 patients with acute symptomatic VTE among 29 centers in Japan. The current study population consisted of 1938 patients who received VKA with prothrombin time-international normalized ratio (PT-INR) measurement >5 times. The primary outcome measure was a composite of symptomatic VTE recurrence or major bleeding at 1 year. The presumed optimal quality of VKA therapy was defined as the combination of PT-INR range and time in therapeutic range (TTR) with the numerically lowest event rate.

Results: The group with TTR ≥70 % based on PT-INR range ≥1.5 and <2.0 showed the lowest cumulative incidence rate. The cumulative 1-year incidence and the adjusted risk for the primary outcome measure were significantly lower in the optimal quality group than in the non-optimal quality group (5.2 % vs. 11.7 %, p = 0.001, and HR 0.49, 95%CI 0.28-0.81). Similarly, the cumulative 1-year incidences of a recurrent VTE, major bleeding, and all-cause death were significantly lower in the optimal quality group (recurrent VTE: 2.5 % vs. 6.0 %, p = 0.02; major bleeding: 2.8 % vs. 7.0 %, p = 0.008; and all-cause death: 2.8 % vs. 12.6 %, p < 0.0001). The lower risk of the optimal quality group relative to non-optimal quality group for the clinical outcomes was consistent regardless of the etiology of VTE (active cancer, transient risk factor, and unprovoked).

Conclusions: The current VTE registry showed the optimal intensity of VKA therapy was target PT-INR range ≥1.5 and <2.0, which could support the current Japanese guideline recommendation, and the good quality of control for VKA therapy of TTR ≥70 % was independently associated with better outcomes.

Keywords: Control; Intensity; Quality; Venous thromboembolism; Vitamin K antagonist.