Gurel 2015.

Study characteristics
Methods	RCT, placebo‐controlled, single‐blind Date of study: not stated Location: one centre, Turkey
Participants	Randomised: 50 participants (mean age 43 years, 25 male) Inclusion criteria Moderate‐severe type plaque psoriasis BSA > 10% Exclusion criteria Pregnancy Had uncontrolled cardiovascular disorder Kidney or liver insufficiencies Had past history of malignant tumours Had received conventional systemic treatments Dropouts No participants lost to follow‐up
Interventions	Intervention Acitretine (0.3 ‐ 0.5 mg/kg/day, 25 mg) (n = 25) Control intervention Placebo (n = 25) Co‐invervention NBUVB
Outcomes	Assessment at 12 weeks Primary outcome Not stated Outcomes: Change in PASI scores from baseline Change in self‐PASI scores from baseline Skindex 30
Notes	Funding: none Declarations of interest: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description
Allocation concealment (selection bias)	Unclear risk	No description
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote (p 3): "The physicians were not blinded" Comment: high risk of performance bias
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote (p 3): "An independent assessor who is not from the team performed the outcome assessment." Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Randomised 50, analysed 50, no loss to follow‐up during the 12 weeks Comment: probably done
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol was available. The prespecified outcomes mentioned in the Methods section appeared to have been reported