Validity of the EQ-5D in pemphigus vulgaris and foliaceus patients Tamási B1, Brodszky V2, Péntek M2, Gulácsi L2, Hajdu K3,4, Sárdy M1, Szegedi A3,4, Bata-Csörgő Zs5, Kinyó Á6, Rencz F2,7 Department of Dermatology, Venereology and Dermatooncology, Faculty of Medicine, Semmelweis University, Mária u. 41., H-1085, Budapest, Hungary. Department of Health Economics, Corvinus University of Budapest, Fővám tér 8. H-1093, Budapest, Hungary. Departments of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98., H-4032, Debrecen, Hungary. Department of Dermatological Allergology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032, Debrecen, Hungary. Department of Dermatology and Allergology, Albert Szent-Györgyi Medical Centre, University of Szeged, Korányi fasor 6, H-6720, Szeged, Hungary. Department of Dermatology, Venereology and Oncodermatology, University of Pécs, Akác u. 1., H-7632, Pécs, Hungary. Hungarian Academy of Sciences, Premium Postdoctoral Research Program, Nádor u. 7, H-1051, Budapest, Hungary. British Journal of Dermatology. DOI: 10.111/bjd.16883

Lead researcher Bela Tamasi, MD Department of Dermatology, Venereology and Dermatooncology, Faculty of Medicine, Semmelweis University

Introduction What’s already known? The detrimental impact of pemphigus on health-related quality of life has been reported in the literature. No studies have used the EQ-5D questionnaire in pemphigus patients, so far.

Objective Our purpose was to assess the quality of life and identify its most important predictors in pemphigus using the EQ-5D health status questionnaire. We aimed to test the validity of EQ-5D in this patient population.

Methods Between 2014 and 2017, a multicentre cross-sectional study was performed at four university dermatology departments in Hungary. Hungarian versions of validated outcome measures were used to assess general (EQ-5D-5L and EQ VAS) and skin-specific quality of life (Dermatology Life Quality Index, DLQI), disease severity (Autoimmune Bullous Skin Disorder Intensity Score), and pain (visual analogue scale, VAS). The value set for England developed by Devlin et al. was applied in this study to derive EQ-5D index scores, whereby utilities range between -0.285 and 1.

Results(1) Our purpose was to assess the quality of life and identify its most important predictors in pemphigus using the EQ-5D health status questionnaire. We aimed to test the validity of EQ-5D in this patient population.

Results(2): Distribution of responses to the five dimensions of the EQ-5D questionnaire

Results (3): Convergent validity of the EQ-5D and EQ VAS Variables EQ-5D-5L (-0.285 to 1) EQ VAS EQ VAS (0-100) 0.607 - DLQI (0-30) -0.619 -0.463 ABSIS (0-206) -0.396 -0.163* Average pain intensity VAS§ (0-100) -0.593 -0.338 Worst pain intensity VAS§ (0-100) -0.499 -0.298 Age (years) -0.252 -0.194 Disease duration (years) 0.182* 0.004* *not significant (p≥0.05) § in the past 3 months

Discussion Pemphigus has a large negative effect of quality of life as assessed by the EQ-5D questionnaire. The EQ-5D allows measuring the health gains associated with high- cost but very effective drugs, such as rituximab. It is very likely that, similarly to psoriasis, the EQ-5D will become the major tool to obtain quality-of-life data in economic evaluations of pemphigus treatments.

Conclusions What does this study add? This is the first study employing the EQ-5D questionnaire in pemphigus. The EQ-5D is a valid instrument for the evaluation of health- related quality of life in pemphigus vulgaris and foliaceus. Pain intensity, mucocutaneous involvement and comorbidities are important predictors of quality of life. The EQ-5D might help to better understand the health loss from pemphigus.

Research team Corvinus University of Budapest, Department of Health Economics Dr Fanni Rencz Dr Valentin Brodszky Prof László Gulácsi Prof Márta Péntek Semmelweis University, Department of Dermatology, Venereology and Dermatooncology Dr. Bela Tamasi Prof Miklós Sárdy University of Debrecen, Departments of Dermatology Prof Andrea Szegedi Dr Krisztina Hajdu Department of Dermatology and Allergology, Albert Szent-Györgyi Medical Centre, University of Szeged Prof Zsuzsa Bata-Csörgő Department of Dermatology, Venereology and Oncodermatology, University of Pécs Dr Ágnes Kinyó

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