Fanni Rencz1,2, Ariel Z Mitev3, Ákos Szabó1,4, Zsuzsanna Beretzky1,5, Adrienn K Poór6, Péter Holló6, Norbert Wikonkál6, Miklós Sárdy6, Sarolta Kárpáti6, Andrea Szegedi7,8, Éva Remenyik7, Valentin Brodszky9. 1. Department of Health Economics, Corvinus University of Budapest, 8 Fővám tér, 1093, Budapest, Hungary. 2. Hungarian Academy of Sciences, Premium Postdoctoral Research Programme, 7 Nádor u, 1051, Budapest, Hungary. 3. Institute of Marketing, Corvinus University of Budapest, 8 Fővám tér, 1093, Budapest, Hungary. 4. Doctoral School of Clinical Medicine, Semmelweis University, 26 Üllői út, 1085, Budapest, Hungary. 5. Doctoral School of Business and Management, Corvinus University of Budapest, 8 Fővám tér, 1093, Budapest, Hungary. 6. Department of Dermatology, Venereology and Dermatooncology, Faculty of Medicine, Semmelweis University, 41 Mária u, 1085, Budapest, Hungary. 7. Departments of Dermatology, Faculty of Medicine, University of Debrecen, 98 Nagyerdei krt, 4032, Debrecen, Hungary. 8. Department of Dermatological Allergology, Faculty of Medicine, University of Debrecen, 98 Nagyerdei krt, 4032, Debrecen, Hungary. 9. Department of Health Economics, Corvinus University of Budapest, 8 Fővám tér, 1093, Budapest, Hungary. valentin.brodszky@uni-corvinus.hu.
Abstract
PURPOSE: Eight of the ten items of the Dermatology Life Quality Index (DLQI) have a 'not relevant' response (NRR) option. There are two possible ways to interpret NRRs: they may be considered 'not at all' or missing responses. We aim to compare the measurement performance of the DLQI in psoriasis patients when NRRs are scored as '0' (hereafter zero-scoring) and 'missing' (hereafter missing-scoring) using Rasch model analysis. METHODS: Data of 425 patients with psoriasis from two earlier cross-sectional surveys were re-analysed. All patients completed the paper-based Hungarian version of the DLQI. A partial credit model was applied. The following model assumptions and measurement properties were tested: dimensionality, item fit, person reliability, order of response options and differential item functioning (DIF). RESULTS: Principal component analysis of the residuals of the Rasch model confirmed the unidimensional structure of the DLQI. Person separation reliability indices were similar with zero-scoring (0.910) and missing-scoring (0.914) NRRs. With zero-scoring, items 6 (sport), 7 (working/studying) and 9 (sexual difficulties) suffered from item misfit and item-level disordering. With missing-scoring, no misfit was observed and only item 7 was illogically ordered. Six and three items showed DIF for gender and age, respectively, that were reduced to four and three by missing-scoring. CONCLUSIONS: Missing-scoring NRRs resulted in an improved measurement performance of the scale. DLQI scores of patients with at least one vs. no NRRs cannot be directly compared. Our findings provide further empirical support to the DLQI-R scoring modification that treats NRRs as missing and replaces them with the average score of the relevant items.
PURPOSE: Eight of the ten items of the Dermatology Life Quality Index (DLQI) have a 'not relevant' response (NRR) option. There are two possible ways to interpret NRRs: they may be considered 'not at all' or missing responses. We aim to compare the measurement performance of the DLQI in psoriasispatients when NRRs are scored as '0' (hereafter zero-scoring) and 'missing' (hereafter missing-scoring) using Rasch model analysis. METHODS: Data of 425 patients with psoriasis from two earlier cross-sectional surveys were re-analysed. All patients completed the paper-based Hungarian version of the DLQI. A partial credit model was applied. The following model assumptions and measurement properties were tested: dimensionality, item fit, person reliability, order of response options and differential item functioning (DIF). RESULTS: Principal component analysis of the residuals of the Rasch model confirmed the unidimensional structure of the DLQI. Person separation reliability indices were similar with zero-scoring (0.910) and missing-scoring (0.914) NRRs. With zero-scoring, items 6 (sport), 7 (working/studying) and 9 (sexual difficulties) suffered from item misfit and item-level disordering. With missing-scoring, no misfit was observed and only item 7 was illogically ordered. Six and three items showed DIF for gender and age, respectively, that were reduced to four and three by missing-scoring. CONCLUSIONS: Missing-scoring NRRs resulted in an improved measurement performance of the scale. DLQI scores of patients with at least one vs. no NRRs cannot be directly compared. Our findings provide further empirical support to the DLQI-R scoring modification that treats NRRs as missing and replaces them with the average score of the relevant items.
Authors: F Rencz; V Brodszky; L Gulácsi; M Péntek; A K Poór; P Holló; A Szegedi; É Remenyik; M Sárdy; A Langenbruch; M A Radtke; M Gutknecht; M Augustin Journal: J Eur Acad Dermatol Venereol Date: 2019-03-19 Impact factor: 6.166
Authors: A Nast; P I Spuls; G van der Kraaij; P Gisondi; C Paul; A D Ormerod; P Saiag; C H Smith; E Dauden; E M de Jong; E Feist; R Jobling; M Maccarone; U Mrowietz; K A Papp; K Reich; S Rosumeck; T Talme; H B Thio; P van de Kerkhof; R N Werner; C Dressler Journal: J Eur Acad Dermatol Venereol Date: 2017-09-11 Impact factor: 6.166
Authors: F Rencz; A K Poór; M Péntek; P Holló; S Kárpáti; L Gulácsi; A Szegedi; É Remenyik; B Hidvégi; K Herszényi; H Jókai; Z Beretzky; V Brodszky Journal: J Eur Acad Dermatol Venereol Date: 2017-11-28 Impact factor: 6.166
Authors: D Pathirana; A D Ormerod; P Saiag; C Smith; P I Spuls; A Nast; J Barker; J D Bos; G-R Burmester; S Chimenti; L Dubertret; B Eberlein; R Erdmann; J Ferguson; G Girolomoni; P Gisondi; A Giunta; C Griffiths; H Hönigsmann; M Hussain; R Jobling; S-L Karvonen; L Kemeny; I Kopp; C Leonardi; M Maccarone; A Menter; U Mrowietz; L Naldi; T Nijsten; J-P Ortonne; H-D Orzechowski; T Rantanen; K Reich; N Reytan; H Richards; H B Thio; P van de Kerkhof; B Rzany Journal: J Eur Acad Dermatol Venereol Date: 2009-10 Impact factor: 6.166
Authors: U Mrowietz; K Kragballe; K Reich; P Spuls; C E M Griffiths; A Nast; J Franke; C Antoniou; P Arenberger; F Balieva; M Bylaite; O Correia; E Daudén; P Gisondi; L Iversen; L Kemény; M Lahfa; T Nijsten; T Rantanen; A Reich; T Rosenbach; S Segaert; C Smith; T Talme; B Volc-Platzer; N Yawalkar Journal: Arch Dermatol Res Date: 2010-09-21 Impact factor: 3.017
Authors: Neuza da Silva; Matthias Augustin; Anna Langenbruch; Ulrich Mrowietz; Kristian Reich; Diamant Thaçi; Wolf-Henning Boehncke; Natalia Kirsten; Alexandra Danckworth; Rachel Sommer Journal: PLoS One Date: 2020-07-01 Impact factor: 3.240