Abidia 2003.

Methods	Randomised controlled trial. Allocation concealed at enrolment. Participants, "carers" (including the surgeons) and observers ("medical assessors") blinded.
Participants	18 people with diabetes with lower‐extremity ulcers 1 to 10 cm in diameter that had not shown signs of healing > 6 weeks since presenting Group 1: 9 randomised Group 2: 9 randomised
Interventions	Group 1: hyperbaric air (control) Group 2: 100% oxygen (treatment) In a multi‐place chamber via hood at a pressure of 2.4 atmospheres absolute (ATA) for 90 minutes daily, 5 days per week, totaling 30 sessions. All participants regularly attended a specialised multi‐disciplinary clinic. Wound care was standardised for all participants. Antibiotic therapy was given if there were clinical signs of infection
Outcomes	Proportion of ulcers healed at week 6; at 6 months; at 1 year Reduction in ulcer size at 6 weeks; at 6 months Major amputation; major amputation Transcutaneous oxygen
Notes	Quality of life undertaken using SF‐36 and HADS. Cost‐effectiveness analysis also undertaken.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Mentions a "randomisation code" but no statement of how randomisation sequence was generated
Allocation concealment (selection bias)	Unclear risk	Quote: "The randomisation was performed using sealed envelopes and the randomisation code was only known to the chamber operator." Comment: no statement that the envelopes were sequentially numbered and opaque
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: “All patients, their carers and medical assessors were blinded to the treatment.”
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: “All patients, their carers and medical assessors were blinded to the treatment.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: “Two patients withdrew during the course of the study (one in the control group required urgent vascular intervention and one in the treatment group dropped out for personal reasons)”
Incomplete outcome data addressed (use of intention‐to‐treat (ITT) analysis)	High risk	Quote: “Data analysis was on an intention‐to‐treat basis.” "Two patients withdrew during the course of the study (one in the control group required urgent vascular intervention and one in the treatment group dropped out for personal reasons)" "At 6 weeks follow‐up, complete healing was achieved in five out of eight ulcers in the treatment group compared with one out of eight ulcers in the control group." Comment: although an intention‐to treat‐design was stipulated, the two patients withdrawing were not included in the final analysis.
Selective reporting (reporting bias)	Unclear risk	No protocol available. Most of the outcomes described in methods section are reported, however only the depression scale for HADS is reported and only as P values (significant)