Ciocon 1997.

Study characteristics
Methods	Study design: randomised Country: USA Setting: 2 centres Intention‐to‐treat: not mentioned
Participants	Number of participants randomly assigned: 90 Number of participants analysed: 90 (45 in each group) Exclusions postrandomisation: not mentioned Losses to follow‐up: not mentioned Age (mean): 79 (SD 3.5) years Sex: male:female: pentoxifylline: 10:34, aspirin: 12:34 Inclusion criteria: aged ≥ 65 years; ankle‐to‐arm pressure < 0.8; not taken aspirin/pentoxifylline over previous 6 months; experienced leg claudication Exclusion criteria: took aspirin or pentoxifylline in previous 6 months; leg rest pain; vascular surgery; coexisting stable angina, severe osteoarthritis, peripheral neuropathy, leg surgery within previous 6 months; ankle‐to‐arm pressure ratio > 0.8
Interventions	Treatment: oral pentoxifylline, 400 mg tid Control: aspirin, 325 mg daily Duration: 6 weeks
Outcomes	Primary: TWD Secondary: ABI
Notes	Treadmill protocol: not specified TWD expressed in metres only
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "were randomly assigned to." Comment: no further information provided.
Allocation concealment (selection bias)	Unclear risk	Not mentioned.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Different treatments: pentoxifylline bid, aspirin once daily.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Unclear risk	Protocol not available; insufficient information available to permit judgement.
Other bias	Low risk	Study appeared free of other bias.