Do the low molecular weight heparins improve efficacy and safety of the treatment of deep venous thrombosis? A meta-analysis.
OBJECTIVE
We compared the efficacy and safety of low molecular weight heparins (LMWH) and unfractionated heparin (UFH) in the treatement of deep venous thrombosis (DVT). A comparison between two daily subcutaneous injections of LMWH against a single injection was also performed.


METHODS
The study was performed by a meta-analysis. Clot improvement in venography, recurrency, total mortality and major hemorrhages were assessed in 4,472 patients with DVT from 21 studies treated with subcutaneous 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, 0.50 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 differences 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 (c2 = 4.99, p = 0.025); however, the two dose regimen was more effective in clot reduction (c2 = 8.56, p = 0.004).


CONCLUSIONS
LMWH is superior to UFH in terms of safety and efficacy. A single daily dose of LMWH dose is a suitable therapeutic regimen and could facilitate the outpatient treatment of venous thromboembolism.
Rocha
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Hematology Service, University Clinic of Navarra, Avenida Pío XII s/n, P.O. 4209, Pamplona, Spain. erocha@unav.es
Martínez-González
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MA
Montes
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Panizo
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D006470:Hemorrhage / Q000139:chemically induced; D006493:Heparin / Q000592:standards / Q000627:therapeutic use / Q000633:toxicity; D006495:Heparin, Low-Molecular-Weight / Q000592:standards / Q000627:therapeutic use* / Q000633:toxicity; D006801:Humans; D010690:Phlebography; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D015996:Survival Rate; D013923:Thromboembolism / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy*
D006495:Heparin, Low-Molecular-Weight; D006493:Heparin