Itching is a significant problem and a mediator between disease severity and quality of life for patients with psoriasis: results from a randomized controlled trial

Summary Background In patients with moderate‐to‐severe psoriasis, health‐related quality of life (HRQOL) has been shown to improve in parallel with improvement in disease severity. Objectives To evaluate the role of pruritus (itch) in mediating the relationship between improvements in disease severity and HRQOL. Methods Data from a phase 2 clinical trial, in which 142 patients with moderate‐to‐severe plaque psoriasis received ixekizumab or placebo, were used for this posthoc analysis. Relationships between improvement in Psoriasis Area and Severity Index (PASI), Itch Visual Analogue Scale (VAS) and Dermatology Life Quality Index (DLQI), as well as in individual DLQI domains (symptoms and feelings, treatment, work and school, daily activities, leisure, and personal relationships) from baseline to week 16 were determined. Multiple hierarchical linear regressions and Sobel tests were conducted to evaluate the results. Results Improvement in PASI was highly correlated with pruritus improvement and improvements in DLQI total and domain scores at week 16 (P