Nielsen 1994.

Methods	Randomised, open‐label trial
Participants	Number; 16 participants 9 received anticoagulant treatment and 7 received no anticoagulant treatment Age: not specified for participants with distal DVT Gender: not specified for participants with distal DVT
Interventions	UFH/phenprocoumon for 3 months vs no anticoagulation. Intervention: sodium heparin administered intravenously. Treatment initiated by bolus injection of 10,000 IU, followed by continuous infusion (20,000 IU of heparin in 500 mL of 5% dextrose) with APTT target at 1.5–2.5. Phenprocoumon was given from the 3rd day. Heparin treatment was continued for ≥ 6 days or until INR had reached 2.0–4.3. Control: participants were treated with phenylbutazone 200 mg 3 times at the day of admission and then 100 mg 3 times daily for the following 9 days. All participants were actively mobilised from the day of admission and wore graduated compressing stockings.
Outcomes	Propagation or development of new VTE
Notes	People with clinical symptoms of PE were excluded. Study protocol involved 90 participants with DVT; 16 were diagnosed with distal DVT. Funding/support: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information about sequence generation process.
Allocation concealment (selection bias)	Low risk	Random allocation.
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.