Hachen 1982.

Study characteristics
Methods	Study design: randomised, double‐blind, placebo‐controlled Method of randomisation: not stated Exclusions post randomisation: none Losses to follow‐up: 2/50 (4%)
Participants	Country: Switzerland Setting: hospital Number: 50 females Age: 10 to 45 years Gender: 50 F Inclusion criteria: recent onset of CVI; no venous surgery, presence of symptoms (heaviness, fatigue, etc.) or aggravation during prolonged sitting or standing or during premenstrual periods Exclusion criteria: pregnancy, diabetes, polyneuropathy, osteo‐articular lesions in the legs, arterial peripheral insufficiency, oral contraceptives, poor co‐operation
Interventions	Treatment: calcium dobesilate 1000 mg per day Control: placebo Duration: 28 days Follow‐up: 28 days
Outcomes	Primary Plethysmographic parameters Symptoms ‐ pain, heaviness, swelling and paraesthesia measured by an ordinal scale scored from ‐3 (total relief) to +1 (deterioration) Secondary Global score of symptoms Side effects
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Fifty female patients with recent onset of venous insufficiency were randomly allocated to two subgroups receiving either calcium dobesilate or a corresponding placebo" Comment: no method of randomisation of participants described
Allocation concealment (selection bias)	Unclear risk	Comment: no method of allocation concealment described
Blinding (patients)	Low risk	Quote: "Fifty female patients with recent onset of venous insufficiency were randomly allocated to two subgroups receiving either calcium dobesilate or a corresponding placebo" Comment: Identical placebo ensures double‐blinding
Blinding (study researchers)	Low risk	Quote: "Fifty female patients with recent onset of venous insufficiency were randomly allocated to two subgroups receiving either calcium dobesilate or a corresponding placebo" Comment: Identical placebo ensures double‐blinding
Blinding (outcome assessment)	Low risk	Quote: "Fifty female patients with recent onset of venous insufficiency were randomly allocated to two subgroups receiving either calcium dobesilate or a corresponding placebo" Comment: Identical placebo ensures double‐blinding
Incomplete outcome data	Low risk	Comment: number of participants in each group described. Participants who withdrew prematurely from the trial described, along with reasons for withdrawal. Four per cent of participants lost to follow‐up
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