Kahle 2006.

Study characteristics
Methods	Study design: randomised, double‐blinded, placebo‐controlled study comparing polidocanol and normal saline Method of randomisation: randomised into 4 blocks with the randomisation program of Microsoft Excel Blinding: patient ‐ yes, treating doctor ‐ unclear, photo evaluator ‐ yes Power calculation: not mentioned Number of patients randomised: 48 Number of patients analysed: 48 Number of exclusions post‐randomisation: 0 Number of withdrawals post‐randomisation: 0 Source of funding: not stated
Participants	Setting: outpatient site Country: Germany Total number: 48 Age: Not mentioned Sex: Not mentioned Inclusion criteria: presence of spider veins Exclusion criteria: not stated
Interventions	Treatment: injection with polidocanol 0.25% or normal saline placebo followed by compression bandages for 24 hours and then compression stockings for 1 week Duration: 4 weeks
Outcomes	1) evaluation of photos by blinded consultants (scale of 0 to 100) 2) evaluation of veins by treating doctor (scale of 0 to 3) 3) Patient satisfaction: scale of 0 to 3
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated program using Microsoft Excel in 4 random blocks.
Allocation concealment (selection bias)	Unclear risk	Method not stated
Blinding (performance bias and detection bias) All outcomes	Low risk	Examining doctor and patients were blinded to allocation. Photos from visits one and two were sent twice to blinded external consultants using different numbering.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete data
Selective reporting (reporting bias)	High risk	The efficacy data on ratings of the treating physician, and the patient satisfaction data were not statistically analysed or presented in a manner that allows for inclusion in a meta‐analysis.
Other bias	Low risk	The study appears to be free of other sources of bias.