Klüken 1971.

Study characteristics
Methods	Study design: randomised, double‐blind, placebo‐controlled Method of randomisation: not stated Exclusions post randomisation: not stated Losses to follow‐up: not stated
Participants	Country: Germany Setting: hospital Number: 60 patients Age: 'adults' Gender: not stated Inclusion criteria: CVI (varicoses or post‐thrombotic syndrome) Exclusion criteria: not stated
Interventions	Treatment: troxerutin 75 mg and coumarin 15 mg per day Control: placebo Duration: 21 days Follow‐up: 21 days
Outcomes	Primary Symptoms ‐ pain, tension measured by a qualitative scale Oedema ‐ circumference of calf and ankle Secondary Not stated
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Double‐blind, randomized, placebo‐controlled. In two parallel groups" Comment: information about methods of randomisation not provided
Allocation concealment (selection bias)	Unclear risk	Comment: no information about methods of allocation concealment provided
Blinding (patients)	Unclear risk	Comment: no information given about methods used for blinding
Blinding (study researchers)	Unclear risk	Comment: no information given about methods used for blinding
Blinding (outcome assessment)	Unclear risk	Comment: no information given about methods used for blinding
Incomplete outcome data	Unclear risk	Comment: number of participants in each group described. No information provided about the number of participants who dropped out of the study prematurely or the number who experienced adverse events
Selective reporting	Unclear risk	Comment: no published protocol identified. No outcomes reported in the methods section
Other bias	Low risk	Comment: none detected