Current issues of ACP Journal Club are published in Annals of Internal Medicine


Economics

Low-molecular-weight heparin was more cost-effective than intravenous heparin for treating proximal venous thrombosis

ACP J Club. 1997 Jul-Aug;127:23. doi:10.7326/ACPJC-1997-127-1-023


Source Citation

Hull RD, Raskob GE, Rosenbloom D, et al. Treatment of proximal vein thrombosis with subcutaneous low-molecular-weight heparin vs intravenous heparin. An economic perspective. Arch Intern Med. 1997 Feb 10;157:289-94.


Abstract

Objective

To evaluate the cost-effectiveness of subcutaneous low-molecular-weight heparin (LMWH) and intravenous heparin in the treatment of proximal venous thrombosis.

Design

Cost-effectiveness analysis based on the results of a randomized controlled trial (The American-Canadian Thrombosis Study).

Setting

Clinical centers in Canada and the United States.

Patients

432 patients with venographically confirmed proximal venous thrombosis.

Intervention

Patients were allocated to either a fixed dose of subcutaneous LMWH (tinzaparin), 175 international factor Xa U/kg of body weight once every 24 hours, or an adjusted dose of continuous intravenous heparin, initial bolus dose of 5000 U followed by 1240 U/h in patients at high risk for bleeding or 1680 U/h in patients at low risk for bleeding. On the second day of initial therapy, warfarin therapy was started for all patients and the dosage was adjusted to maintain an international normalized ratio between 2.0 and 3.0. Warfarin therapy continued for at least 3 months.

Main cost and outcome measures

The main outcome measures were frequency of recurrent venous thromboembolism and death. The cost data were based on the actual costs of patient care. Indirect costs were not included. The economic viewpoint of the analysis was that of a ministry of health in Canada or an insurance company in the United States. The findings are reported in 1992 Canadian and U.S. dollars, according to costs at urban hospitals in Alberta and the midwestern United States.

Main results

LMWH was effective and safe. The total cost per 100 LMWH recipients was Canadian $399 687 or U.S. $335 687, with a frequency of objectively documented recurrent venous thromboembolism of 2.8%. The total cost per 100 heparin recipients was Canadian $414 655 or U.S. $375 836, with a frequency of recurrent venous thromboembolism of 6.9%. The use of LMWH was associated with cost savings of Canadian $15 252 or U.S. $40 149 per 100 patients treated. The potential use of outpatient LMWH therapy in 37% of the patients increased the Canadian cost savings to $95 736 and the U.S. cost savings to $91 332. Sensitivity analyses did not alter the findings.

Conclusion

Compared with intravenous heparin, low-molecular-weight heparin was as effective and safe and was more cost-effective for the treatment of proximal venous thrombosis.

Sources of funding: Heart and Stroke Foundation, Calgary, Alberta, and Novo Nordisk, Bagsvaerd, Denmark.

For article reprint: Dr. R.D. Hull, Department of Medicine, The University of Calgary, Health Sciences Centre, Room 1474, 3330 Hospital Drive North West, Calgary, AB T2N 4N1, Canada. FAX 403-283-0400.


Commentary

LMWH has proven effective for preventing and treating acute deep venous thrombosis (1, 2). Compared with unfractionated heparin, LMWH is easier to use because it has predictable pharmacokinetics, is available in fixed dosing, and does not require monitoring of coagulation indices. Indeed, LMWH is easy enough to use that selected patients with acute proximal venous thrombosis can be safely and effectively treated at home (3).

In the cost analysis by Hull and colleagues, the LMWH tinzaparin turns out to be less expensive than unfractionated heparin. The savings result from the ease of administration and, according to the randomized trial that served as the basis of the analysis, improved outcomes. The authors were careful to vary their cost assumptions (sensitivity analyses) to account for unpredictable market variations. On the basis of this analysis and the accumulated weight of evidence on the effectiveness of LMWH, it would make both clinical and economic sense to use tinzaparin rather than heparin for acute venous thrombosis. The economic argument would be even stronger if indirect costs, such as hospital days compared with days at home, had been included in the analysis. It is too early to generalize the results of this analysis to other types of LMWH and other thrombotic conditions. Both the cost and effectiveness of different LMWHs may vary.

We have entered a new era in treating acute venous thrombosis. The trend toward using LMWH to treat patients with venous thrombosis at home is supported by convincing clinical evidence and is justifiable in term of costs.

Daniel M. Becker, MD, MPH
University of Virginia School of MedicineCharlottesville, Virginia, USA


References

1. Clagett GP, Anderson FA Jr, Heit J, Levine MN, Wheeler HB. Prevention of venous thromboembolism. Chest. 1995;108(4 Suppl): 312S-34S.

2. Hyers TM, Hull RD, Weg JG. Antithrombotic therapy for venous thromboembolic disease. Chest. 1995;108(4 Suppl):335S-51S.

3. Levine M, Gent M, Hirsh J, et al. A comparison of low-molecular-weight heparin administered primarily at home with unfraction-ated heparin administered in the hospital for proximal deep-vein thrombosis. N Engl J Med. 1996;334:677-81.