Marchiori 2002.

Methods	Single‐centre RCT.
Participants	60 consecutive participants with ST of great saphenous vein confirmed by ultrasonography; 26 males, 34 females; mean age 62 years. Not reported if participants were hospitalised or non‐hospitalised.
Interventions	UFH (12,500 IU sc for 1 week then 10,000 IU). UFH (5000 IU). Study treatment given for 4 weeks.
Outcomes	Asymptomatic and symptomatic recurrence or extension of ST and VTE (or both recurrence and extension) after treatment and at 3 and 6 months. Safety outcomes: major bleeding, HIT, overall mortality.
Notes	Systemic or local anti‐inflammatory drugs (or both) allowed. Funding: not reported. Disclosure of potential COI: the authors report no COI.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐based: "List generated by a computer."
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not reported.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Ultrasound assessment performed by blinded investigators. However, not reported if participants and investigators evaluating all other events were blind to study treatment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes reported.