Diehm 1996a.

Methods	Study design: 3 parallel arms, randomised, double‐blinded (for placebo and HCSE only). Method of randomisation: not reported. Exclusion post randomisation: none. Losses to follow up: not reported. Quality score = 2.
Participants	Country: Germany. Setting: hospital. No: 240 entered, drop outs not reported. Age: (mean) 52 years. Sex: not reported. Inclusion criteria: oedema due to CVI (confirmed by medical history, clinical findings, venous Doppler and duplex sonography. Exclusion criteria: venotherapeutic drugs within the last 6 weeks before run‐in.
Interventions	Treatment: 1 capsule HCSE (standardised to 50 mg escin) twice daily. Control: placebo or compression stockings. Duration: 12 weeks.
Outcomes	Primary: (not explicitly stated) leg volume (ml). Secondary: (not explicitly stated) circumference, symptoms .
Notes	Standardised mean difference (95% CI): Primary: HCSE versus placebo 0.49 (0.14 to 0.85) HCSE versus compression ‐0.03 (‐0.31 to 0.25)
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	"Patients were treated over a period of 12 weeks in a randomised partially blinded placebo controlled paralles study"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	It is unclear how incomplete data were addressed
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting
Other bias	Unclear risk	No evidence of other biases