Cost/Death Averted With Venous Thromboembolism Prophylaxis
Study Objective: To compare the cost-effectiveness of warfarin or enoxaparin with no prophylaxis for prevention of venous thromboembolism in patients undergoing total knee replacement (TKR) or knee arthroplasty.
Design. Literature search and retrospective database analysis.
Patients: Cohort of 42,692 patients over 40 years old who underwent TKR or knee arthroplasty, with a subsequent length of stay of at least 1 day, and who did not die postoperatively.
Measurements and Main Results: Both warfarin and enoxaparin were superior to no prophylaxis with regard to costs and clinical outcomes. Enoxaparin was associated with medical charges of $26,455/patient and prevented 194 deaths/10,000 patients. Warfarin was associated with medical charges of $27,360/patient and prevented 124 deaths/10,000 patients.
Conclusions: A wide range of model estimates and assumptions identify enoxaparin as the prophylaxis modality of choice for preventing venous thromboembolism and subsequent clinical complications following total knee replacement surgery.
Venous thromboembolism (VTE) is a frequent cause of morbidity and mortality among hospitalized patients. Each year approximately 300,000-600,000 hospitalizations are associated with deep vein thrombosis (DVT) or pulmonary embolism (PE) in the United States. An estimated 200,000 patients die annually as a result of PE. Surgical patients are most highly susceptible to thromboembolic events, and those undergoing orthopedic surgery of the lower limbs, including total knee replacement (TKR), have the highest risk overall. In the absence of DVT prophylaxis, the prevalence of DVT is 40-84% in these patients, with 9-20% of thrombi involving proximal veins. The prevalence of PE in this group is 1.8-7%, with fatal disease occurring in 0.2-0.7%.
At its Sixth Consensus Conference on Antithrombotic Therapy, the American College of Chest Physicians reviewed the various prophylaxis modalities available for DVT and PE in patients who have undergone TKR. The resulting recommendations, published in 2001, assign the highest grade (grade 1A) to therapies supported by efficacy data from rigorously designed published clinical trials. Two therapies are designated as grade 1A recommendations for TKR surgery: low-molecular-weight heparin or adjusted-dose warfarin.
We drew from published efficacy and safety data to evaluate the cost-effectiveness of enoxaparin and warfarin for prevention of DVT and fatal pulmonary emboli in patients who have undergone TKR. (Total knee replacement was inclusive of knee arthroplasty.) Warfarin and enoxaparin each were compared with a no-prophylaxis option. The metric for analysis was cost/death averted. To our knowledge, no other published study has evaluated these treatment options in terms of deaths averted in patients undergoing TKR.
Study Objective: To compare the cost-effectiveness of warfarin or enoxaparin with no prophylaxis for prevention of venous thromboembolism in patients undergoing total knee replacement (TKR) or knee arthroplasty.
Design. Literature search and retrospective database analysis.
Patients: Cohort of 42,692 patients over 40 years old who underwent TKR or knee arthroplasty, with a subsequent length of stay of at least 1 day, and who did not die postoperatively.
Measurements and Main Results: Both warfarin and enoxaparin were superior to no prophylaxis with regard to costs and clinical outcomes. Enoxaparin was associated with medical charges of $26,455/patient and prevented 194 deaths/10,000 patients. Warfarin was associated with medical charges of $27,360/patient and prevented 124 deaths/10,000 patients.
Conclusions: A wide range of model estimates and assumptions identify enoxaparin as the prophylaxis modality of choice for preventing venous thromboembolism and subsequent clinical complications following total knee replacement surgery.
Venous thromboembolism (VTE) is a frequent cause of morbidity and mortality among hospitalized patients. Each year approximately 300,000-600,000 hospitalizations are associated with deep vein thrombosis (DVT) or pulmonary embolism (PE) in the United States. An estimated 200,000 patients die annually as a result of PE. Surgical patients are most highly susceptible to thromboembolic events, and those undergoing orthopedic surgery of the lower limbs, including total knee replacement (TKR), have the highest risk overall. In the absence of DVT prophylaxis, the prevalence of DVT is 40-84% in these patients, with 9-20% of thrombi involving proximal veins. The prevalence of PE in this group is 1.8-7%, with fatal disease occurring in 0.2-0.7%.
At its Sixth Consensus Conference on Antithrombotic Therapy, the American College of Chest Physicians reviewed the various prophylaxis modalities available for DVT and PE in patients who have undergone TKR. The resulting recommendations, published in 2001, assign the highest grade (grade 1A) to therapies supported by efficacy data from rigorously designed published clinical trials. Two therapies are designated as grade 1A recommendations for TKR surgery: low-molecular-weight heparin or adjusted-dose warfarin.
We drew from published efficacy and safety data to evaluate the cost-effectiveness of enoxaparin and warfarin for prevention of DVT and fatal pulmonary emboli in patients who have undergone TKR. (Total knee replacement was inclusive of knee arthroplasty.) Warfarin and enoxaparin each were compared with a no-prophylaxis option. The metric for analysis was cost/death averted. To our knowledge, no other published study has evaluated these treatment options in terms of deaths averted in patients undergoing TKR.