Low molecular weight heparin and unfractionated heparin in thrombosis prophylaxis: Meta-analysis based on original patient data

A meta-analysis (MA) based on original patient data has been performed comp aring low molecular weight heparins (LMWH) with unfractionated heparin (UFH ) in thrombosis prophylaxis after major surgical interventions. The analyse s have been done for the following prespecified groups of studies: all stud ies, studies in orthopaedic surgery (OS) and studies in general surgery (GS , with further separation into low-dose studies [GS-LD] and high-dose studi es [GS-HD]). Deep vein thrombosis (DVT, all locations) and wound haematoma were used as primary endpoints for efficacy and safety, respectively. The a nalysis confirms the results of previous publication-based meta-analyses. I n GS there is no relevant difference between LMWH and UFH regarding efficac y; the safety results strongly depend on the dosage: under low-dose LMWH th e risk of wound haematoma is significantly lower, under high-dose LMWH it i s significantly higher than under UFH. However, most of the studies in the last group used regimens of LMWH that are not considered appropriate any mo re. Ln OS there is a trend towards a better efficacy and safety of LMWH. In addition, LMWHs are superior to UFH, in OS, with respect to the secondary endpoints proximal DVT and pulmonary embolism. The rates of proximal DVT an d pulmonary embolism, respectively, are consistently lower under LMWH than under UFH, whereas slightly smaller rates of distal DVT are observed under UFH. (C) 2001 Elsevier Science Ltd. All rights reserved.