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


Economics

Low-molecular-weight heparin was cost-effective for perioperative prevention of DVT

ACP J Club. 1997 Mar-Apr;126:51. doi:10.7326/ACPJC-1997-126-2-051


Source Citation

Bergqvist D, Lindgren B, Mätzsch T. Comparison of the cost of preventing postoperative deep vein thrombosis with either unfractionated or low molecular weight heparin. Br J Surg. 1996 Nov;83:1548-52.


Abstract

Objective

To compare the cost-effectiveness of preventing deep venous thrombosis (DVT) after surgery with no prophylaxis, selective treatment, or general treatment with either unfractionated heparin (UH) or low-molecular-weight heparin (LMWH).

Design

Cost-effectiveness analysis based on data from 2 reviews and 2 randomized controlled trials of thromboprophylaxis, and financial data from a university hospital in Sweden.

Setting

Sweden.

Patients

Patients who were having elective general abdominal surgery and were at moderate risk for developing DVT, and patients who were having elective hip surgery and were at high risk for developing DVT.

Intervention

The strategies compared were no prophylaxis, selective treatment of DVT after general surveillance with the fibrinogen uptake test, prophylaxis with low-dose UH, and prophylaxis with LMWH.

Main cost and outcome measures

Expected costs per patient of each of the 4 management strategies for general abdominal surgery and hip surgery. Based on the reviews and randomized controlled trials, the prophylactic effectiveness of UH was 90% in abdominal surgery and 72% in hip surgery; the prophylactic effectiveness of LMWH was 90% in abdominal surgery and 79% in hip surgery. The costs of heparin were based on the mean price of LMWHs available in Sweden, the doses were recommended by the heparin manufacturers, and duration of prophylaxis was assumed to be 7 days after abdominal surgery and 10 days after hip surgery. The costs of the surveillance test (for selective treatment), prophylaxis, frequency of thromboembolism, and frequency of bleeding complications associated with prophylaxis were taken into account for calculating the expected costs.

Main results

For abdominal surgery, the expected costs per patient for no prophylaxis, selective treatment, UH, and LMWH were 1950 Swedish kronor (SKr) (US $254), SKr 5710 ($742), SKr 735 ($96), and SKr 665 ($86), respectively. For hip surgery, the costs were SKr 3930 ($511), SKr 10 790 ($1403), SKr 1730 ($225), and SKr 1390 ($181), respectively.

Conclusions

In patients having elective general abdominal surgery or elective hip surgery, general prophylaxis of deep venous thrombosis with unfractionated heparin or low-molecular-weight heparin was more cost-effective than no prophylaxis or selective treatment after surveillance. A strategy of low-molecular-weight heparin was less expensive than one of unfractionated heparin.

Sources of funding: Swedish Medical Research Council and Swedish Heart and Lung Foundation.

For article reprint: Professor D. Bergqvist, Department of Surgery, University Hospital, S-751 85 Uppsala, Sweden. FAX 46-18-508-127.


Commentary

Without anticoagulant prophylaxis, DVT occurs in as much as 60% of patients who receive a total hip replacement and 25% of general surgery patients (1, 2). In patients having hip surgery, use of LMWH reduces the rate of DVT to about 70% to 75% of that observed with UH (2, 3), a clinically important improvement. In abdominal surgery, the benefit is less clear, but many clinical trials have found that LMWH reduces the frequency of DVT more than does UH (2). LMWH is at least as safe as UH (1-3), but it may cost up to 10 times more than UH (1). Is LMWH worth this additional expense?

Bergqvist and colleagues help to answer this question. The methods of this study were appropriate, but the findings depended on the costs of prophylaxis and treatment in Sweden. Although LMWH reduced costs more than UH in the base-case analyses, the sensitivity analyses showed that the expected total costs of prophylaxis and treatment were greater with LMWH if the price of LMWH were more than 37% higher than that of UH for general surgery or more than 128% higher than that of UH for hip surgery. Thus, the cost-effectiveness of LMWH may not compare favorably with that of UH in certain practice settings.

Recommendations for prophylaxis during hip replacement include LMWH, low-intensity oral anticoagulation, or adjusted-dose UH (1). Although the study by Bergqvist and colleagues provides further economic rationale for use of LMWH during hip surgery, a direct prospective economic comparison of LMWH and oral anticoagulation would help clinicians choose among these common alternatives. Whether LMWH provides a cost-effective alternative to UH in abdominal surgery depends on the relative prices of LMWH and UH.

Douglas K. Owens, MD
Veterans Affairs Palo Alto Health Care SystemPalo Alto, California, 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. Nurmohamed MT, Rosendaal FR, Büller HR, et al. Low-molecular-weight heparin versus standard heparin in general and orthopaedic surgery: a meta-analysis. Lancet. 1992;340:152-6.

3. Anderson DR, O'Brien BJ, Levine MN, et al. Efficacy and cost of low-molecular-weight heparin compared with standard heparin for the prevention of deep vein thrombosis after total hip arthroplasty. Ann Intern Med. 1993;119:1105-12.