Papageorgiou 2000.

Methods	Study design: parallel design Duration of follow‐up: 8 weeks
Participants	Total number of participants randomised: N = 45 Inclusion criteria: grade I acne severity and ≥ 5 inflammatory lesions Exclusion criteria Severe nodulo‐cystic acne requiring oral treatment Using any acne therapy, systemic or topical, for 2 weeks before study entry, using any antibiotics and oestrogens during the study Pregnancy Sites of acne: face Severity of acne and corresponding criteria of judgement: unclear Treatment before study: unclear Participants' baseline data presented as mean (SD) for each group Sex ratio (male/female): A = 4/9; B = 3/10; C = 4/11 Age (years): A = 29.5 (range 19 to 50); B = 26.2 (range 14 to 43); C = 27.5 (range 14 to 50) Duration of acne (year): unclear
Interventions	Interventions in Group A Topical treatment: chloroxylenol/zinc oxide Regimen: leave‐on Concentration: unclear Vehicle: cream Dose: twice daily Duration: 8 weeks Number of participants assigned: unclear Interventions in Group B Topical treatment: BPO Regimen: leave‐on Concentration: 5% Vehicle: cream Dose: twice daily Duration: 8 weeks Number of participants assigned: unclear Interventions in Group C Topical treatment: placebo Regimen: leave‐on Concentration: N/A Vehicle: cream Dose: twice daily Duration: 8 weeks Number of participants assigned: unclear Co‐interventions: none
Outcomes	Primary outcomes of review interest Participant global self‐assessment of acne improvement (assessed as worse, no change (0 to 9%), mild improvement (10% to 39%), moderate improvement (40% to 69%), marked improvement (70% to 89%), and clearance (> 90%)) Withdrawal due to adverse effects, including worsening of acne Secondary outcomes of review interest Investigator‐assessed change in lesion counts Percentage of participants experiencing any adverse event Other outcomes reported in the study Investigator graded overall improvement on a scale (assessed as worse, no change (0 to 9%), mild improvement (10% to 39%), moderate improvement (40% to 69%), marked improvement (70% to 89%), and clearance (> 90%))* Participants were evaluated at baseline and at 4 and 8 weeks of treatment *This outcome was assessed as the primary outcome in the trial
Study details	Study period: unclear Country: unclear Setting: unclear Number of study centres: multiple but unclear Washout period: 2 weeks washout for any systemic or topical acne therapy Registered number: unclear ITT analysis: no
Publication details	Language of publication: English Funding: unclear Conflicts of interest: not specified Publication status: full article
Stated aim for study	Quote from publication: "the purpose of this trial was to evaluate this new product and compare its efficacy and safety with a more traditional acne therapy, 5% benzoyl peroxide cream"
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: no information on the method used to generate the random sequence was provided
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information about allocation concealment was provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "this trial was a double‐blind controlled randomized parallel group comparison..." Comment: who was blinded remains unclear. However, complete blinding was difficult as treatment‐related adverse events were more common in the BPO group
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "this trial was a double‐blind controlled randomized parallel group comparison..." Comment: who was blinded remains unclear. However, complete blinding was difficult as treatment‐related adverse events were more common in the BPO group
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "four patients either voluntarily left the study or were lost to follow‐up" Comment: numbers of and reasons for withdrawal for each group were unclear
Selective reporting (reporting bias)	Unclear risk	Comment: although all outcomes listed in the methods section were reported, we could not identify the corresponding protocol nor relevant information on a trial registry to confirm that selective reporting was avoided
Other bias	High risk	Quote: "the three groups were well matched in terms of number of patients, age, sex distribution and severity of acne (Table 1)" Comment: baseline characteristics were similar between groups. The washout period for systemic acne treatments was not long enough