Decousus 1998.

Methods	Study design: randomised controlled trial. Method of randomisation: stratified according to centre. Concealment of allocation: not blinded for treatment allocation, blinded for outcome assessment. Exclusions post‐randomisation: none. Lost to follow‐up: 4 (1 vital status; 3 for the assessment of non‐fatal events).
Participants	Country: France (44 centres). Setting: hospital. No.: 400 participants. Age: mean 72. Sex: 190 males. Inclusion criteria: acute proximal DVT confirmed by venography with or without symptomatic PE; at high risk for PE. Exclusion criteria: placement of previous filter; contraindication to or failure of anticoagulant therapy; curative anticoagulant therapy lasting more than 48 hours; indication for thrombolysis; short life expectancy; allergy to iodine; hereditary thrombophilia; severe renal or hepatic failure; pregnancy; likelihood of non‐compliance.
Interventions	Treatment: LMWH: Enoxaparin (Rhone‐Poulenc Rorer) body weight‐adjusted fixed dose (1 mg per kg body weight), s.c., twice daily (100 anti‐factor Xa IU per mg). Control: UFH: APTT‐adjusted, continuous i.v. infusion (started with 500 IU per kg of body weight per day), after initial i.v. bolus dose of 5000 IU. Treatment duration: 8 to 12 days; discontinuation if INR was 2 or more for 2 consecutive days. Oral anticoagulation: warfarin or acenocoumarol started on day 4 and continued for at least 3 months.
Outcomes	Primary: symptomatic or asymptomatic PE within the first 12 days after randomisation; all symptomatic recurrent VTE. Secondary: major haemorrhage during the initial treatment period; mortality.
Notes	Follow‐up: 2 years. The outcome of recurrent VTE was only reported for a follow‐up period of 3 months (also included as the incidence at the end of follow‐up).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed by a computer system.
Allocation concealment (selection bias)	Low risk	Allocation was performed by a central 24‐hour telephone system.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Not blinded for treatment allocation. Comment: given the clinical outcomes of the study, review authors judged that the non‐blinding of the participants and staff was unlikely to have affected the outcomes.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All pulmonary investigations and all documented symptomatic events, including deaths, were validated by an independent adjudication committee whose members were unaware of the treatment assignments.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for missing outcome data unlikely to be related to true outcome.
Selective reporting (reporting bias)	Low risk	The published report includes all expected outcomes.
Other bias	Unclear risk	The study has a potential source of bias due to the fact that 2 interventions (the effectiveness of a vena cava filter and the efficacy of LMWH) are investigated in the same population. There is insufficient Information about the number of participants with a vena cava filter across intervention groups.