This is not the most recent version of the article. View current version (7 MAY 2014)
Heparin for the prevention of venous thromboembolism in general medical patients (excluding stroke and myocardial infarction)
Editorial Group: Cochrane Peripheral Vascular Diseases Group
Published Online: 8 JUL 2009
Assessed as up-to-date: 7 MAY 2009
Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
How to Cite
Alikhan R, Cohen AT. Heparin for the prevention of venous thromboembolism in general medical patients (excluding stroke and myocardial infarction). Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD003747. DOI: 10.1002/14651858.CD003747.pub2.
- Publication Status: Edited (no change to conclusions)
- Published Online: 8 JUL 2009
This is not the most recent version of the article. View current version (07 MAY 2014)
Venous thromboembolic disease has been extensively studied in surgical patients. The benefit of thromboprophylaxis is now generally accepted, but it is medical patients who make up the greater proportion of the hospital population. Medical patients differ from surgical patients with regard to their health and the pathogenesis of thromboembolism and the impact that preventative measures can have. The extensive experience from thromboprophylaxis studies in surgical patients is therefore not necessarily applicable to non-surgical patients.
To determine the effectiveness and safety of heparin thromboprophylaxis in general medical patients.
The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched 24 April 2009) and the Cochrane Central Register of Controlled Trials in The Cochrane Library (last searched Issue 2, 2009)
We handsearched meeting abstracts, and consulted with colleagues and investigators as well as the manufacturers of the various LMWH preparations to identify unpublished or missed studies.
Randomised controlled trials comparing unfractionated heparin (UFH) or low molecular weight heparin (LMWH) with placebo or no treatment, or comparing UFH with LMWH.
Data collection and analysis
One author identified possible trials, and the other author confirmed eligibility for inclusion in the review. Both authors extracted the data. Disagreements were resolved by discussion. We performed the meta-analysis as a fixed-effect model with relative risks.
A significant risk reduction in deep vein thrombosis (DVT) by 60% (relative risk (RR) 0.40; 95% confidence interval CI 0.31 to 0.53; P < 0.00001) and pulmonary embolism (PE) by 42% (RR 0.58; 95% CI 0.43 to 0.80; P = 0.0007) was observed with heparin compared with placebo or no treatment. However, heparin resulted in a significant increase in major haemorrhage (RR 2.18; 95% CI 1.28 to 3.72; P = 0.004) and minor haemorrhage (RR 1.74; 95% CI 1.26 to 2.41; P = 0.0008). There was no statistically significant difference in efficacy between LMWH and UFH. There was a statistically significant 72% risk reduction in major bleeding when LMWH was compared with UFH (RR 0.28; 95% CI 0.10 to 0.78; P = 0.02).
The data from this review support the use of heparin thromboprophylaixs in medical patients presenting with an acute medical illness. Although the analysis found no significant difference in efficacy between LMWH and UFH, it did note differences in the incidence of DVT and clinical PE with a significantly reduced risk of bleeding in favour of LMWH.
Plain language summary
Anticoagulants to prevent deep vein thrombosis or pulmonary embolism in general medical patients excluding those with stroke or myocardial infarction
Blood clots may form in the veins of patients who are admitted to hospital suffering from an acute medical illness. These blood clots may travel to the lungs and become fatal.
Heparin is a blood thinning drug, which has been shown to reduce the occurrence of blood clots in patients after they have had surgery. Heparin exists in two forms, the original unfractionated form and a newer form called low molecular weight heparin (LMWH).
This review of trials in non-surgical patients who have suffered an acute medical illness, found that heparin reduced the number of patients suffering blood clots in the veins and reduced the number who developed a blood clot that travelled to the lungs. It also found that patients who were given LMWH developed fewer bleeding complications.