Danielsson 2002.

Study characteristics
Methods	Study design: randomised, double‐blind, placebo‐controlled Method of randomisation: sealed envelope principle Exclusions post randomisation: none Losses to follow‐up: 4/101 (4%)
Participants	Country: Sweden Setting: hospital Number: 101 patients Age: 18 to 65 years Gender: 28 M:73 F Inclusion criteria: symptomatic CVI with reflux venous, CEAP II classification Exclusion criteria: diabetes; inflammatory, heart, renal, hepatic or peripheral arterial disease. Treatment with diuretics or anti‐inflammatory drugs (steroids, NSAIDs). Allergic reactions to venoactive drugs
Interventions	Treatment: micronised purified flavonoid fraction (MPFF) 1000 mg per day Control: placebo Duration: 60 days Follow‐up: 60 days
Outcomes	Primary Symptoms ‐ heaviness, tiredness, ankle swelling, pain and cramps measured by an ordinal scale (0 to 3) Oedema ‐ foot volumetry by plethysmography Reflux by Duplex ultrasonography Improvement in global score of symptoms Secondary Side effects
Notes	No description of double‐blind
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "One hundred and one patients with symptomatic CVD were randomly allocated to treatment with either MPFF (51 patients) or placebo..." Comment: no methods described for randomisation of participants
Allocation concealment (selection bias)	Low risk	Quote: "After informed consent, patients were randomised in a blinded fashion (sealed envelope principle)" Comment: sealed envelope principle considered a good method to ensure allocation concealment
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	Low risk	Comment: number of participants in each group described. In addition, information given about numbers of participants who withdrew prematurely (4/101; 4%)
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