Bollinger 1977.

Methods	Study design: double‐blinded, randomised Country: Switzerland Setting: single centre Intention‐to‐treat: not mentioned
Participants	Number of participants randomly assigned: 26 Number of participants analysed: 19 Exclusions post randomisation: none Losses to follow‐up: 7 Age: pentoxifylline: mean 63.9 years, placebo: mean 59.6 years Sex: pentoxifylline: 9 male, 1 female, placebo: 8 male, 1 female Inclusion criteria: intermittent claudication (Fontaine stage II) Exclusion criteria: malleolar arteries could not be compressed by a cuff (mediasclerosis)
Interventions	Treatment: oral pentoxifylline, 200 mg 3 times daily Control: placebo Duration: 8 weeks
Outcomes	Primary: mean TWD Secondary: ABI
Notes	Treadmill protocol: 3.2 km/h at 12.5% inclination Mean TWD expressed in metres only Participants were instructed to refrain from smoking during the study and to walk daily for at least 1 hour
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	States 'allocated at random to receive treatments'; no other information provided
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	'Both pentoxifylline and placebo were presented in identical tablet form and supplied in containers of 40 tablets, identified only by a code number'
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data
Selective reporting (reporting bias)	Unclear risk	Protocol not available; insufficient information available to permit judgement
Other bias	High risk	Differences in clinical baseline data between treatment groups