Lagerstedt 1985.

Methods	Randomised, open label trial 52 randomised, 1 excluded and lost follow‐up
Participants	Number: 51 participants 23 received warfarin and 28 control group with no anticoagulation Age (mean ± SD; years); 65.0 ± 14.4, warfarin group; 60.9 ± 12.4, control group Gender (M/F): 14/9, warfarin group; 15/13, control group
Interventions	UFH/warfarin for 3 months vs no anticoagulation All participants received a 5‐day course of sodium heparin intravenously, 500–600 IU/kg/day in 6 divided doses. Intervention: participants receiving oral anticoagulation were started on warfarin as soon as a diagnosis was confirmed by phlebography. The aim was to achieve an INR of 2.5–4.2. Heparin treatment was extended for 1–2 days if the therapeutic level was not reached on the 5th day. Control: no anticoagulation All participants were asked to wear graded compression stocking during the study
Outcomes	VTE recurrence, clinical or revealed (or both) on imaging
Notes	People with previous VTE, PE, thrombi extending into popliteal vein, malignancy were excluded. Funding/support: quote: "The study was supported in part by grants from the National Organisation against Heart and Lung Diseases."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Used sealed envelopes.
Allocation concealment (selection bias)	Low risk	Used sealed envelopes.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label study.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	No blinding of outcome assessment but the review authors judged that the outcome measurement was unlikely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing data.
Selective reporting (reporting bias)	Low risk	Published report included all expected outcomes.
Other bias	Low risk	Study appeared free of other sources of bias.