Direct and Indirect Effect of Guselkumab on Anxiety, Depression, and Quality of Life in Patients with Moderate-to-Severe Plaque Psoriasis: A Mediation Analysis

Abstract Introduction Treating plaque psoriasis (PsO) with guselkumab (GUS) promotes skin clearance and is associated with improvements in health-related quality of life (HRQoL), anxiety, and depression. It is unclear whether improvements in patient-reported outcomes are due to resolution of skin symptoms or the direct result of GUS treatment. Methods Two phase 3, placebo- and active-comparator-controlled studies randomized patients with moderate-to-severe PsO to GUS, placebo (crossing over to GUS at week 16), or adalimumab. Post hoc mediation analyses examined direct and indirect effects of GUS, versus adalimumab, on Dermatology Life Quality Index (DLQI) or Hospital Anxiety and Depression Scale (HADS) after adjusting for indirect effects mediated by skin clearance, evaluated via Psoriasis Area and Severity Index (PASI), to determine the direct effect of GUS on dermatology HRQoL, depression, and anxiety. Results Compared with adalimumab, the natural direct effect (NDE) of GUS on change in DLQI from baseline was − 2.04 (P