Bergqvist 1981.

Study characteristics
Methods	Study design: randomised, cross‐over, double‐blind, placebo‐controlled Method of randomisation: not stated Exclusions post randomisation: none Losses to follow‐up: 6/149 (4%)
Participants	Country: Sweden Setting: outpatient clinic and local population Number: 149 patients Age: 'adults' Gender: 33 M:116 F Inclusion criteria: symptoms related to varicose veins and CVI Exclusion criteria: not stated
Interventions	Treatment: oxirutoside 1000 mg intravenous injection followed by 1 tablet of 500 mg per 8 hours Control: placebo Duration: 28 days Follow‐up: 28 days
Outcomes	Primary Symptoms ‐ pain, cramps, tired legs, pruritus, swelling, side effects Signs ‐ plethysmographic values, calf circumference Secondary Not stated
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "They were then randomly allocated to treatment with either HR or identical placebo" Comment: no details of randomisation method provided
Allocation concealment (selection bias)	Unclear risk	Comment: no method of allocation concealment described
Blinding (patients)	Low risk	Quote: "The placebo regime was identical" and "... or identical placebo" Comment: Identical placebo ensures double‐blinding
Blinding (study researchers)	Low risk	Quote: "The placebo regime was identical" and "... or identical placebo" Comment: Identical placebo ensures double‐blinding
Blinding (outcome assessment)	Low risk	Quote: "The placebo regime was identical" and "... or identical placebo" Comment: Identical placebo ensures double‐blinding
Incomplete outcome data	Low risk	Comment: number of participants in each group described. Loss to follow‐up described along with exclusions after randomisation, including reasons
Selective reporting	Low risk	Comment: no published protocol identified, and no differences between outcomes reported in the methods section and those reported in the results section
Other bias	Low risk	Comment: none detected