Beitner 1985b.

Methods	Randomised controlled trial conducted in Sweden. Each participant had 2 leg ulcers each and acted as his or her own control. Ulcers were the unit of randomisation
Participants	10 participants (20 ulcers) were recruited. There were no details of baseline characteristics, including ulcer infection status
Interventions	Interventions were applied to 10 participants with 2 leg ulcers each, acting as his or her own control. For each participant, one ulcer was treated with 20% benzoyl peroxide lotion and the other with normal saline solution. For both ulcers, treatment was applied by moistening a sterile sponge compress, cut to the exact shape of the ulcer, with the respective solution. The sponge dressings were then covered with a thick pad and kept in place with a gauze stocking. The ulcer margins were protected with zinc ointment, and a supporting elastic bandage was applied. Dressings were changed 3 times a week for 42 days
Outcomes	Mean ± SD percentage ulcer area remaining at 42 days: Normal saline solution 93.7% ± 15.2% 20% benzoyl peroxide lotion 59.6% ± 12.3% Adverse effects: No information provided for either treatment
Notes	There were no withdrawals. This trial report described 3 separate RCTs recruiting 31 participants in total. All participants had 2 leg ulcers each and acted as his or her own control. One other RCT was included (Beitner 1985a) and the other was excluded (Beitner 1985c).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The ulcer chosen for BPO treatment was randomised according to left or right leg and most distal or proximal location. When ulcers were situated at the same level, medial or lateral localization was randomised" Comment: the sequence generation method was not stated
Allocation concealment (selection bias)	High risk	Quote: "the randomisation and treatment was given in the day care unit by personnel not involved in the evaluation of results" Comment: the information provided suggests that group allocation was likely to be unconcealed
Blinding (performance bias and detection bias) Participant blinded to the intervention	Unclear risk	Comment: no information provided
Blinding (performance bias and detection bias) Outcome assessor blinded to the intervention	Unclear risk	Quote: "the randomisation and treatment was given in the day care unit by personnel not involved in the evaluation of results" Comment: Comment: no statement that outcome assessors were blind to treatment allocation
Incomplete outcome data (attrition bias) Drop out rate described	Low risk	Comment: it was clear that there were no withdrawals
Incomplete outcome data (attrition bias) Drop out rate acceptable	Low risk	Comment: it was clear that there were no withdrawals
Incomplete outcome data (attrition bias) ITT analysis	Low risk	Comment: it was clear that there were no withdrawals, and the review authors assume that all randomised participants were included in the analysis
Baseline factors comparable	Unclear risk	Comment: no information provided on baseline characteristics of participants/ulcers in each group