Abstract
BACKGROUND: In the absence of thromboprophylaxis, patients undergoing total hip arthroplasty (THA) are at increased risk for venous thromboembolism (VTE). The objective of this study was to compare the efficacy and safety of edoxaban with enoxaparin for the prevention of VTE after THA in Japan. METHODS: This was a phase 3, double-blind, double-dummy, noninferiority study. Patients undergoing elective, unilateral primary THA were randomized to receive edoxaban 30 mg once daily (n = 307) or enoxaparin 2000 IU (equivalent to 20 mg) twice daily (n = 303) for 11 to 14 days. The primary efficacy endpoint was the incidence of VTE. Safety endpoints included the incidence of major or clinically relevant nonmajor (CRNM) bleeding. RESULTS: The incidence of VTE, based on venography and clinical surveillance, was 2.4 % in the edoxaban group and 6.9 % in the enoxaparin group (P <0.001). The absolute difference in the incidence of VTE was -4.5 % (95 % confidence interval [CI]: -8.6, -0.9), which was within the noninferiority margin set at 8 % for the difference and established the noninferiority of edoxaban to enoxaparin. Since the upper limit of the 95 % CI of the absolute difference was less than 0 %, the superiority of edoxaban over enoxaparin was demonstrated. The incidence of major or CRNM bleeding was 2.6 % in the edoxaban group and 3.7 % in the enoxaparin group (P = 0.475). CONCLUSIONS: Oral edoxaban 30 mg once daily was superior to subcutaneous enoxaparin 2000 IU twice daily in the prevention of VTE following THA without increasing the risk for major or CRNM bleeding.