Once versus twice daily injections of low molecular weight heparin for the initial treatment of venous thromboembolism

van Dongen CJ, Mac Gillavry MR, Prins MH

Published Online:

March 16, 2011

Blood clots in the veins (venous thromboembolism) can develop spontaneously or after surgery or bed rest. Venous thromboembolism can be life threatening if clots travel to the lungs. Blood-thinning drugs such as heparin are used to dissolve clots. Low molecular weight heparin (LMWH) can be given by injection, enabling people to leave hospital. The usual treatment is two injections a day, but once a day would be more convenient. The review of trials found that one LMWH injection a day is apparently as safe and effective as twice daily injections. However, there is a possibility that the risk of recurrent venous thromboembolism might be higher when people are treated once daily.

Abstract (click to read)

Background:

In the initial treatment of venous thromboembolism (VTE) low molecular weight heparin (LMWH) is administered once or twice daily. A once daily treatment regimen is more convenient for the patient and may optimise home treatment. However, it is not clear whether a once daily treatment regimen is as safe and effective as a twice daily treatment regimen.

Objectives:

To compare the efficacy and safety of once daily versus twice daily administration of LMWH.

Search strategy:

The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched April 2005), and Cochrane Central Register of Controlled Trials (CENTRAL) (last searched 2005, Issue 2). We searcHed MEDLINE (inception to April 2005) and EMBASE (inception to April 2005). In addition, we identified trials by handsearching relevant journals, checking cross-references and through personal communication with experts.

Selection criteria:

Randomised clinical trials in which LMWH given once daily is compared with LMWH given twice daily for the initial treatment of venous thromboembolism.

Data collection and analysis:

Two authors assessed trials for inclusion and extracted data independently.

Main results:

Five studies were included with a total of 1508 participants. The pooled data showed a statistically non-significant difference in recurrent venous thromboembolism between the two treatment regimens (OR 0.82, 0.49 to 1.39). A comparison of major haemorrhagic events (OR 0.77, 0.40 to 1.45) and mortality (OR 1.14, 0.62 to 2.08) also showed a statistically non-significant difference between the two treatment regimens.

Authors' conclusions:

Once daily treatment with LMWH is as effective and safe as twice daily treatment with LMWH. However, the 95% confidence interval implies that there is a possibility that the risk of recurrent VTE might be higher when people are treated once daily. Hence, the decision to treat a person with a once daily regimen will depend on the evaluated balance between increased convenience and the potential for a lower efficacy.

This record should be cited as:

van Dongen CJ, Mac Gillavry MR, Prins MH. Once versus twice daily low molecular weight heparin for the initial treatment of venous thromboembolism. Cochrane Database of Systematic Reviews 2005, Issue 3. Art. No.: CD003074. DOI: 10.1002/14651858.CD003074.pub2

Assessed as up to date:

May 15, 2005

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Primary Review Group:

Peripheral Vascular Diseases Group

Health topics:

Heart & circulation > Deep vein thrombosis > Treatment

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Once versus twice daily injections of low molecular weight heparin for the initial treatment of venous thromboembolism

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