Do the low molecular weight heparins improve efficacy and safety of the treatment of deep venous thrombosis? A mete-analysis

Background and Objectives. We compared the efficacy and safety of low molec ular weight heparins (LMWH) and unfractionated heparin (UFH) in the treatme nt of deep venous thrombosis (DVT). A comparison between two daily subcutan eous injections of LMWH against a single injection was also performed. Design and Methods. The study was performed by a meta-analysis. Clot improv ement in venography, recurrency, total mortality and major hemorrhages were assessed in 4,472 patients with DVT from 21 studies treated with subcutane ous LMWH or UFH. Results. An improvement in clot reduction (odds ratio 0.73, 95% confidence interval 0.59 to 0.90, p = 0.004), a decrease in total mortality (0.68, 0.5 0 to 0.91, p = 0.012) and a lower incidence of hemorrhage (0.65, 0.43 to 0. 98, p = 0.047) were observed in LMWH treated patients. There were no differ ences in recurrences (0.78, 0.59 to 1.04, p = 0.10). A single dose of LMWH was better than two in reducing major bleeding (chi(2) = 4.99, p = 0.025); however, the two dose regimen was more effective in clot reduction (chi(2) = 8.56, p = 0.004). Interpretation and Conclusions. LMWH is superior to UFH in terms of safety and efficacy. A single daily dose of LMWH dose is a suitable therapeutic re gimen and could facilitate the outpatient treatment of venous thromboemboli sm. (C) 2000, Ferrata Storti Foundation.