Comparison of health-related quality of life in atopic dermatitis, hidradenitis suppurativa, pemphigus and psoriasis

This study aims to explore the measurement agreement between direct and indirect health utility measures in four chronic dermatological conditions (atopic dermatitis, hidradenitis suppurativa, pemphigus, psoriasis). Outpatients survey data collected between 2015 and 2021 were analysed. Health-related quality of life (HRQoL) outcome measures included time trade-off (TTO), EQ-5D-5L and Dermatology Life Quality Index (DLQI). Descriptive statistics were computed for the pooled sample and four diseases. Mean, standard deviation (SD), median, interquartile range (IQR), ceiling and floor effects were calculated for TTO, EQ-5D-5L and DLQI utilities. Bland-Altman plots and intraclass correlation coefficients (ICC) were applied to investigate the agreement between health utility measures. Sociodemographic characteristics (age, sex, educational level, employment status) and health-related information (disease duration, outpatient care visits in the past 3 months and disease severity) impact on utilities was investigated by Tobit regressions. The sample includes N = 765 patient responses with a mean age of 41.5 (SD = 16.2), majority being males (52.7%). Total sample mean utilities were the highest according to TTO (0.83), followed by EQ-5D-5L and vDLQI (0.81 and 0.81) and lowest in mDLQI (0.77). Measurement agreement was found only between TTO and EQ-5D-5L. Skin-disease severity impacted all health state utilities, though only TTO differentiated utility values according to disease type. The discrepancies between the TTO and DLQI warn to compare DLQI-based utilities in different dermatological conditions with extreme caution.