Validity of the EQ-5D in patients with pemphigus vulgaris and pemphigus foliaceus

Background No studies to date have employed the EuroQoL EQ-5D questionnaire to assess health-related quality of life (HRQoL) in patients with pemphigus. Objectives To evaluate the HRQoL of patients with pemphigus by the EQ-5D and to analyse the convergent and known-groups validity of the EQ-5D in this patient population. Methods Between 2014 and 2017, a multicentre cross-sectional study was carried out. Outcome measures included the five-level EQ-5D (EQ-5D-5L), Dermatology Life Quality Index (DLQI), Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and an average pain intensity visual analogue scale (VAS) for the past 3 months. Results In total, 109 consecutive patients with pemphigus participated in the study (mean age 57 years; 64% women). Among the EQ-5D dimensions, the most problems were reported regarding pain/discomfort (50%), mobility (43%) and anxiety/depression (43%). No significant difference was found in mean EQ-5D index scores between patients with pemphigus vulgaris and those with pemphigus foliaceus (0 center dot 81 vs. 0 center dot 86, P = 0 center dot 14). The mean EQ-5D index scores of patients with limited, moderate, significant and extreme pemphigus were 0 center dot 88, 0 center dot 82, 0 center dot 72 and 0 center dot 67, respectively (P = 0 center dot 001). The number of comorbidities was associated with greater impairment in EQ-5D index scores (P < 0 center dot 001). DLQI (r(s) = -0 center dot 62, P < 0 center dot 001) and the average pain intensity VAS (r(s) = -0 center dot 59, P < 0 center dot 001) more strongly correlated with the EQ-5D index scores than did ABSIS (r(s) = -0 center dot 40, P < 0 center dot 001). Conclusions This is the first study employing the EQ-5D questionnaire in pemphigus. The EQ-5D is a valid measure of HRQoL in patients with pemphigus that can be useful both in clinical practice and in economic evaluations to assess the health gains associated with new effective treatments.