Study designs of evaluations included in the review
Randomised controlled trials (RCTs) comparing the efficacy of LMWHs and UFH were included if they studied more than 50 patients. The follow-up periods ranged from 7 days to a median of 23 months.
Specific interventions included in the review
LWMHs and UFH, given either subcutaneously or as an infusion. The LMWH studies were of dalteparin, enoxaparin, tinzaparin and nadroparin. The doses were calculated on the basis of the patient's weight and the adjusted partial thromboplastin time. The duration of heparin treatment ranged from 5 days to 10 days. Warfarin treatment was started between day 1 and day 10. The patients were treated on both an in- and out-patient basis.
Participants included in the review
Patients who had had a first episode of symptomatic deep-venous thrombosis, as confirmed by objective tests including venography, duplex ultrasonography and impedance plethysmography.
Outcomes assessed in the review
The outcomes assessed were: total mortality, the percentage of venograms improved, recurrent thrombombolic events, and major bleeding complications.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.