Kar 2013.

Study characteristics
Methods	Aim of study: to compare the efficacy of oral isotretinoin and oral isotretinoin with 20% SA peels in participants with moderate to severe acne Design: parallel Unit of allocation: patients Allocation: unclear Blinding: investigator‐blinded Duration of trial (from recruitment to last follow‐up): carried out between April 2012 and March 2013 Dropouts: no
Participants	Population description: moderate to severe acne Setting: Department of Skin and VD of a Tertiary Care Hospital of Eastern India Randomised number: 60 Age: range 18 to 25 years; mean ± SD 20 ± 1.9 years in combination group; 20.6 ± 1.9 years in isotretinoin group Sex: 16/14 in combination group; 13/17 in isotretinoin group Severity of illness: moderate to severe MAS score 64.1 ± 4.4 in combination group; 63 ± 5.1 in isotretinoin group
Interventions	Name of treatment group: salicyclic acid and isotretinoin group; n = 30 Description: 20 mg oral isotretinoin once daily along with 20% SA peels every two weeks Treatment period: 16 weeks Timing: 20 mg oral isotretinoin once daily along with 20% SA peels every two weeks Name of treatment group: Isotretinoin group; n = 30 Description: 20 mg oral isotretinoin Treatment period: 16 weeks Timing: once daily
Outcomes	Primary outcomes Participants' global self‐assessment of acne improvement (e.g. measured by a 4‐point scale: excellent, good, fair, and poor). Authors did not report this outcome Withdrawal for any reason. No withdrawals Secondary outcomes Change in lesion counts (total or inflamed and non‐inflamed separately). Percentage reduction of total lesions, week 16, SDs were missing Physicians' global evaluation of acne improvement. Authors did not report this outcome Minor adverse events (assessed as total number of participants who experienced at least one minor adverse event). Only mentioned 'drying of lips', no usable data Quality of life. Authors did not report this outcome Other outcomes that were not analysed in this review MAS
Notes	Funding: SA peel (Vedasol ‐ 20 gel from Vedaderm Inc. Chicago) used in this study was supplied by Percos India. Isotretinoin (Cap Tretiva 20 mg) was supplied by Intas Pharmaceuticals bearing lot number S12B018 and expiry date January 2014
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were randomised using a random number table." Comment: random number table is reliable for random sequence generation
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Investigator 1 (1st author) did the group allocation of the patients using a random number table. Investigator 2 (2nd author) performed the chemical peeling on patients in the second group using 20% SA." Comment: blinding of participants probably insufficient
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The 3rd investigator (3rd author) was blinded from the group allocation and treatment modalities. She did the MASI scoring and evaluation of all patients at all the visits." Comment: binding of investigator probably sufficient
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants completed the study, no missing outcome data
Selective reporting (reporting bias)	Low risk	Results reported for all prespecified outcomes in the methods section
Other bias	Low risk	No other potential bias identified