Complete skin clearance and Psoriasis Area and Severity Index response rates in clinical practice: predictors, health‐related quality of life improvements and implications for treatment goals

Summary Background Psoriasis Area and Severity Index (PASI) 90 is suggested to be the new standard endpoint for randomized controlled trials of biologics for psoriasis, whereas treatment guidelines often still refer to PASI 75. Objectives To analyse in a real‐world setting: firstly, what factors are associated with higher levels of treatment response to biologics; secondly, the health‐related quality of life gains associated with different response levels in clinical practice. Methods Biologically naïve patients with PASI, Dermatology Life Quality Index (DLQI) and EuroQol (EQ)‐5D outcomes before (maximum 6 months) and after (3–12 months) switch to biologics during registration in the Swedish National Registry for Systemic Treatment of Psoriasis (PsoReg) were included (n = 515). Patient characteristics associated with higher treatment response were analysed by regression analyses. Improvements in absolute PASI, DLQI and EQ‐5D were assessed in different PASI percentage response levels. Results High PASI percentage response was associated with higher PASI before switch and lower body mass index. DLQI and EQ‐5D improved within all responder groups (P < 0·001). The magnitude of improvements in DLQI (P = 0·02) differed between responder groups. The mean (SD) DLQI improvements for PASI 75