title: Low molecular weight heparin administered once versus twice daily in patients with venous thromboembolism: a meta-analysis.
abstract: 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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Hamilton Civic Hospitals Research Centre and McMaster University, Ontario, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Couturaud
authors.forename: J A
authors.initials: JA
authors.lastname: Julian
authors.forename: C
authors.initials: C
authors.lastname: Kearon
mesh_terms: D000208:Acute Disease; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D017985:Dalteparin / Q000627:therapeutic use; D004334:Drug Administration Schedule; D017984:Enoxaparin / Q000627:therapeutic use; D006470:Hemorrhage / Q000139:chemically induced / Q000401:mortality; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D017762:Nadroparin / Q000627:therapeutic use; D016017:Odds Ratio; D011655:Pulmonary Embolism / Q000188:drug therapy* / Q000401:mortality; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D016019:Survival Analysis; D013923:Thromboembolism / Q000188:drug therapy* / Q000401:mortality; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000188:drug therapy* / Q000401:mortality
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D006495:Heparin, Low-Molecular-Weight; D017762:Nadroparin; D017985:Dalteparin