Subcutaneous low-molecular-weight heparin vs warfarin for prophylaxis of deep vein thrombosis after hip or knee implantation. An economic perspective
R. D. Hull, G. E. Raskob, G. F. Pineo, W. Feldstein, D. Rosenbloom, A. Gafni, D. Green, J. Feinglass, A. A. Trowbridge and C. G. Elliott
Faculty of Medicine, University of Calgary, Alberta.
BACKGROUND: Postoperative venous thrombosis and pulmonary embolism present
a major clinical threat to patients undergoing total hip or knee
arthroplasty. We performed an economic evaluation of warfarin sodium and
subcutaneous low-molecular-weight heparin sodium prophylaxis comparing cost
and effectiveness. METHODS: A consecutive series of 1436 patients who
underwent hip or knee arthroplasty comparing these 2 regimens in a
randomized trial with objective documentation of outcomes provided the
opportunity to perform economic evaluations for Canada and the United
States. RESULTS: Deep vein thrombosis was documented in 231 (37.4%) of 617
patients given warfarin and in 185 (31.4%) of 590 patients given
low-molecular-weight heparin (P = .03). In Canada, warfarin and
low-molecular-weight heparin (tinzaparin sodium) incurred costs per 100
patients of $11,598 and $9,197, respectively, providing a cost savings of
$2,401 for the low-molecular-weight heparin group. The drug cost of
low-molecular-weight heparin (tinzaparin) was $6 per day and for warfarin
was $0.32 per day. Sensitivity analysis showed that low-molecular-weight
heparin is more costly if drug costs are increased by 1.5-fold (ie, the
cost of tinzaparin is increased from $6 per day to $8.82 per day or more).
In the United States, the analysis was also not definitive;
low-molecular-weight heparin was more costly than warfarin at drug costs of
$15 and $2.01 per day, respectively. CONCLUSIONS: Our findings indicate
that the decision to use low-molecular-weight heparin or warfarin
prophylaxis in patients undergoing major joint replacement surgery is a
finely tuned trade-off. Prophylaxis with low-molecular-weight heparin is
equally or more effective than the more complex prophylaxis with warfarin.
Major bleeding is uncommon but less frequent with warfarin use. The most
significant parameters that influence the comparative cost-effectiveness
are the cost of the drug, the cost of international normalized ratio
monitoring, and the costs associated with major bleeding. The analysis also
demonstrates that the results are health care system dependent (Canada vs
US). In Canada, low-molecular-weight heparin (tinzaparin) is less costly
because it avoids the need for international normalized ratio monitoring.
In the United States, the drug cost for low-molecular-weight heparin will
likely be the principal determinant of relative cost-effectiveness.
New Anticoagulants for Treatment of Venous Thromboembolism
Gross and Weitz
Arterioscler. Thromb. Vasc. Bio. 2008;28:380-386.
ABSTRACT
| FULL TEXT
Selecting an agent for prophylaxis of venous thromboembolism
Myers
Am J Health Syst Pharm 2006;63:2448-2450.
FULL TEXT
Comparing the Costs, Risks, and Benefits of Competing Strategies for the Primary Prevention of Venous Thromboembolism
Avorn and Winkelmayer
Circulation 2004;110:IV-25-IV-32.
ABSTRACT
| FULL TEXT
Prevention of Venous Thromboembolism: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy
Geerts et al.
Chest 2004;126:338S-400S.
ABSTRACT
| FULL TEXT
The Economics of Venous Thromboembolism Prophylaxis: A Primer for Clinicians
Davidson et al.
Chest 2003;124:393S-396S.
ABSTRACT
| FULL TEXT
Prolonged Thromboprophylaxis With Oral Anticoagulants After Total Hip Arthroplasty: A Prospective Controlled Randomized Study
Prandoni et al.
Arch Intern Med 2002;162:1966-1971.
ABSTRACT
| FULL TEXT
Prevention of Venous Thromboembolism
Geerts et al.
Chest 2001;119:132S-175S.
FULL TEXT
Risks vs Benefits in Total Joint Surgery
Lotke and Heit
Chest 1999;116:843-845.
FULL TEXT
Is Impedance Plethysmography a Safe Test After Total Joint Replacement?
Dixon et al.
VASC ENDOVASCULAR SURG 1998;32:255-260.
ABSTRACT
