Tom 2005.

Methods	RCT; prospective, randomised, double‐blind, placebo‐controlled clinical trial Setting: Foot clinic at the Veterans Affairs Medical Center, San Diego Country: USA Duration of follow‐up: 16 weeks Duration of treatment: 4 weeks Funding source: Supported by OrthoNeutrogena Unit of analysis: Some participants had more than 1 ulcer (22 participants with 24 ulcers)
Participants	24 participants Inclusion criteria: Lower extremity ulcer and a diagnosis of diabetes mellitus Exclusion criteria: Patients unable to give informed consent; had a known bleeding disorder; were pregnant at the time of enrolment; had infected ulcers or nearby tissues; or had lower extremity ulcers due to large artery disease (by clinical examination or abnormal ankle‐brachial index, or both) Ulcer characteristics at baseline (size of ulcer, number of ulcers, duration of ulceration where reported): Not reported Infection status at baseline: Not infected
Interventions	Group 1 (n = 11): Placebo (normal saline solution that was coloured the same as the topical tretinoin). Group 2 (n = 13): Topical 0.05% tretinoin solution (Retin‐A; Ortho Pharmaceutical Corp, Raritan, NJ). The randomly assigned solution was applied directly to the wound bed and left in contact for 10 minutes every day; it was then rinsed off with normal saline.
Outcomes	Primary review outcomes: Proportion of ulcers healed; time to healing (partially reported) Secondary review outcomes: None
Notes	24 participants included, 22 participants analysed (13 + 11 ulcers)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomization was performed by an uninvolved third party who used a computer‐generated random sequence to balance the numbers of the 2 treatment groups"
Allocation concealment (selection bias)	Unclear risk	Quote: "Each newly enrolled patient was assigned a topical solution in ascending order" Comment: Not clear if the sequence was foreseeable with this method
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "all dispensed bottles of solutions were identical in appearance (identified by number only), and neither the investigators nor the patients were aware of the treatment group to which patients were assigned until the study was completed" Comment: The double‐blind appears to have been respected.
Blinding of outcome assessment (detection bias) Wound healing	Low risk	As above
Blinding of outcome assessment (detection bias) Infection/resolution of infection	Unclear risk	Not relevant
Blinding of outcome assessment (detection bias) Secondary outcomes	Unclear risk	Not relevant
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: All outcomes reported as outlined in methods. Protocol not obtained.
Selective reporting (reporting bias)	Low risk	Comment: 24 participants were randomised; 22 completed the study and were considered for the outcomes, 20 with 1 foot ulcer and 2 with 2 foot ulcers.
Other bias	High risk	Comment: Some participants had multiple ulcers, but this was not accounted for.