Prevention of Venous Thromboembolism in Internal Medicine with Unfractionated or Low-molecular-weight Heparins: A Meta-analysis of Randomised Clinical Trials
Patrick Mismetti (1) , Silvy Laporte-Simitsidis (1) , Bernard Tardy (2) , Michel Cucherat (3) , Andréa Buchmüller (1) , Daphné Juillard-Delsart (1) , Hervé Decousus (1)
From the (1) Clinical Pharmacology Unit and the (2) Intensive Care Unit, Thrombosis Research Group, University Hospital of Saint-Etienne, (3) Clinical Pharmacology Unit, Cardiological Hospital of Lyon, France
Summary
Background. The prevention of venous thromboembolic disease is less
studied in medical patients than in surgery. Methods. We performed a
meta-analysis of randomised trials studying prophylactic unfractionated
heparin (UFH) or low-molecular-weight heparin (LMWH) in internal
medicine, excluding acute myocardial infarction or ischaemic stroke. Deepvein
thrombosis (DVT) systematically detected at the end of the treatment
period, clinical pulmonary embolism (PE), death and major bleeding were
recorded. Results. Seven trials comparing a prophylactic heparin treatment
to a control (15,095 patients) were selected. A significant decrease in DVT
and in clinical PE were observed with heparins as compared to control (risk
reductions = 56% and 58% respectively, p 0.001 in both cases), without
significant difference in the incidence of major bleedings or deaths. Nine
trials comparing LMWH to UFH (4,669 patients) were also included. No
significant effect was observed on either DVT, clinical PE or mortality.
However LMWH reduced by 52% the risk of major haemorrhage
(p = 0.049). Conclusions. This meta-analysis, based on the pooling of data
available for several heparins, shows that heparins are beneficial in the
prevention of venous thromboembolism in internal medicine.