Brandjes 1997.

Methods	Study design: randomised controlled trial Method of randomisation: sealed envelopes, blocks of 8 Concealment of allocation: not stated Blinding: participants not blinded. Observer and outcome assessor: blinding unclear Follow‐up: 5 to 8 years (median 6.3) Losses to follow‐up: treatment group, 4 were lost to follow‐up and 19 died; non‐intervention group, 2 were lost to follow‐up and 18 died
Participants	Country: The Netherlands No. of participants: 194 Age: mean age 60 years Sex: males 109; females 86 Inclusion criteria: consecutive outpatients with a first episode of venogram‐proven proximal DVT Exclusion criteria: life expectancy < 6 months, paralysis of the leg, bilateral thrombosis, leg ulcers or extensive varicosity, and current use of compression stockings
Interventions	Intervention group (n = 96): below‐knee elastic compression stockings, made to measure (Neodurelna Varitex) with an ankle pressure of 40 mmHg Control group (n = 98): no intervention Start of compression stockings: 2 to 3 weeks after DVT diagnosis
Outcomes	Primary: cumulative incidence of mild to moderate PTS Secondary: VTE recurrence, compliance
Notes	Follow‐up assessments were scheduled at 3 and 6 months, then every 6 months. At each follow‐up visit, presence and severity of PTS were scored on a standardised scale.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description of random sequence generation. Quote:"Randomisation was done by a sealed envelope technique in blocks of eight."
Allocation concealment (selection bias)	Low risk	Quote:"Randomisation was done by a sealed envelope technique in blocks of eight."
Blinding (performance bias and detection bias) Objective outcome(s)	Unclear risk	Quote: "Patients were asked not to wear their stockings on the day of assessment. Each assessment was done by an independent investigator who was unaware of the measurements recorded at the previous assessment and who was not involved in the final scoring."
Blinding (performance bias and detection bias) Subjective outcome(s)	High risk	The outcome PTS was based on a scoring system containing subjective and objective criteria. Subjective criteria, most of which were patient‐reported items, are at high risk of bias because participants were not blinded. For objective criteria, risk of bias is unclear. Blinding of investigators is not described clearly. Furthermore, stockings could leave typical imprints on the skin, which could lead to breaking of blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Numbers and reasons for loss of follow‐up are reported and balanced across groups. A Kaplan‐Meier analysis was done to deal with censored cases.
Selective reporting (reporting bias)	Low risk	No study protocol is available. All outcomes of the "Methods" section of the article are reported.
Other bias	Low risk	Study appears to be free of other potential sources of bias.