Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Maintenance of remission
Systematic review	36 people with psoriasis affecting 40% or more of body, who achieved clearance with PUVA plus etretinate prior to the trial Data from 1 RCT	Absence of relapse 1 year 9/16 (56%) with low-dose etretinate (half of the maximum dose tolerated to achieve clearance) 3/20 (15%) with placebo	ARR 41% 95% CI 12% to 70%	Effect size not calculated	low-dose etretinate