PREVENTION OF VENOUS THROMBOEMBOLISM WITH RIVAROXABAN AFTER TOTAL HIP REPLACEMENT: ECONOMIC IMPACT OF EXTENDED THROMBOPROPHYLAXIS

Abstract

Venous thromboembolism (VTE) is a potentially fatal complication after total hip replacement (THR) and may be associated with a considerable economic burden. In many centres, thromboprophylaxis using a subcutaneous (sc) anticoagulant in patients undergoing THR is restricted to 14 days or less. Rivaroxaban is a once-daily, oral, direct Factor Xa inhibitor in advanced clinical development for thromboprophylaxis after major orthopaedic surgery; it does not require monitoring or dose adjustment. In a phase III study, RECORD2, oral rivaroxaban 10 mg, given once daily for 35±4 days, significantly reduced the incidence of the primary endpoint (deep vein thrombosis, pulmonary embolism and all-cause mortality), compared with 40 mg sc enoxaparin, given for 14 days (2.0% vs 9.3%, respectively; relative risk reduction 79%; p< 0.001). The incidence of bleeding was low and similar in both groups, despite extended thromboprophylaxis with rivaroxaban. This analysis demonstrates the economic impact of extended thromboprophylaxis with oral rivaroxaban. The effect of rivaroxaban on healthcare costs was based on the primary efficacy results, and the associated reduced administration and monitoring costs, and includes non-drug costs only. The cost of symptomatic VTE was taken from published sources in the US and the UK 2007 NICE Guidelines. It was assumed that nurses spent 3 mins/day administering enoxaparin and training patients to self-inject for outpatient use. Hospital duration was 5 days. In the UK, full blood counts should be taken every 3 days when receiving enoxaparin. The total US health-care resource cost was $192/patient for enoxaparin and $39 for rivaroxaban (excluding drug costs). This saving of $153 was driven by reduced hospital costs associated with fewer VTEs when using rivaroxaban. In the UK, the total healthcare cost/patient was £44 with enoxaparin and £2 with rivaroxaban – savings driven equally by reduced hospitalization and monitoring costs with rivaroxaban prophylaxis. The different cost savings in the US and UK are due to higher US hospital costs. The costs of post-thrombotic syndrome (PTS) were excluded in this analysis. PTS has an estimated 5-year rate of 21% after asymptomatic VTE and 30% after symptomatic VTE, at a total cost/patient of more than $11,000 in the US and £4000 in the UK. Given the reduction in all VTE events with rivaroxaban, there are potential further healthcare cost savings due to reduced PTS. The RECORD2 study showed that extended prophylaxis (35 days) with rivaroxaban was significantly more effective than short-term enoxaparin (14 days) for the prevention of VTE, and was not associated with an increased risk of bleeding. This analysis illustrates an additional benefit of once-daily, oral rivaroxaban in the reduction in healthcare costs related to administration and monitoring.