LOW-MOLECULAR-WEIGHT HEPARIN AND UNFRACTIONATED HEPARIN IN THROMBOSISPROPHYLAXIS AFTER MAJOR SURGICAL INTERVENTION - UPDATE OF PREVIOUS METAANALYSES

Background Previous meta-analyses comparing low molecular weight hepar in (LMWH) and unfractionated heparin for thrombosis prophylaxis after surgical interventions need updating. Methods This is a publication-ba sed meta-analysis of 36 double-blind studies including 16 583 patients . Main outcome measures are incidence of deep vein thrombosis (efficac y) and wound haematoma (safety). Results In general surgery there is n o increased efficacy in favour of LMWH (odds ratio (OR) 0.88, 95 per c ent confidence interval (c.i.) 0.60-1.30) but there exists a higher in cidence of bleeding complications (OR 1.47, 95 per cent c.i. 1.07-2.01 ). Low-dose LMWH is equally efficacious (OR 1.03, 95 per cent c.i. 0.8 5-1.26) but safer than unfractionated heparin (OR 0.68, 95 per cent c. i. 0.56-0.82). In orthopaedic surgery there is a trend towards an incr eased efficacy for LMWH (OR 0.83, 95 per cent c.i. 0.68-1.02) with equ ivalent safety (OR 0.96, 95 per cent c.i. 0.68-1.36). Conclusion A sup eriority of LMWH is suggested but heterogeneity might make generalizab ility to future patients questionable. A meta-analysis on individual p atient data should be the next step before randomizing additional pati ents in future trials.