Heparins and curative treatment of venous thromboembolic disease: Meta-analysis

Heparin treatment of venous thromboembolic disease has been validated since 1960. Nevertheless no study was sufficient to determine an optimal therapeutic schedule between sub-cutaneous (SC) unfractionated heparin (UFH), intravenous (IV) UFH and low molecular weight heparin (LMWH). One meta-analysis showed a significant risk reduction of recurrent thromboembolic events (OR = 0.58, CI 95 per cent [0.34-0.99]) and a non-significant risk reduction of haemorrhagic events (OR = 0.78 [0.40-1.52]) with UFH SC compared to UFH IV, but homogeneity testing was significant (p < 0.001). Some discrepancy was shown between the results of the three meta-analyses which compared LMWH to UFH according to the selection criteria of clinical trials used. With an exhaustive selection, LMWH involved a. non-significant risk reduction of recurrent thromboembolic events (OR = 0.66 [0.41-1.07], p = 0.09), and a non-significant risk reduction of haemorrhagic events (OR = 0.65 [0.36-1.16], p = 0.15). So no definitive conclusion could be drawn but it seems that UFH can be recommended whatever the administration route or LMWH for deep vein thrombosis treatment.