Summary
Background. Low molecular weight heparin is as effective and safe as unfractionated heparin
for treatment of acute venous thromboembolism. It is uncertain whether low molecular
weight heparin should be administered once-daily or twice-daily in this setting. Method. A meta-analysis of randomized studies which directly compared once- and twice-daily
administration of low molecular weight heparin for the treatment of acute venous thromboembolism
was performed. A literature search was performed using Advanced Pub Med and the Cochrane
library database, and abstracts from recent meetings were reviewed. Two investigators
extracted data independently. Results. Five studies, involving 1522 patients, were eligible. There were no statistically
significant differences in the frequencies of symptomatic (odds ratio, 0.85 in favor
of once-daily therapy at three months, p = 0.6), and asymptomatic, recurrent venous
thromboembolism; total and major bleeds (odds ratio, 1.16 in favor of twice-daily
therapy at 10 days, p = 0.8); and death, at 10 days, as well as at three months of
follow-up. Conclusion. Once- daily low molecular weight heparin appears to be as effective and safe as
twice-daily administration for the acute treatment of venous thromboembolism. However,
there is inadequate data from studies that directly compared once-daily and twice-daily
administration to be able to exclude the possibility of a higher frequency of fatal
bleeding with once-daily therapy.
Keywords
Low molecular weight heparin - venous thrombosis - meta-analysis
