Rasch analysis holds no brief for the use of the Dermatology Life Quality Index (DLQI) in Chinese neurodermatitis patients

Health and Quality of Life Outcomes

Research

Weihui Zeng¹  Shengxiang Xiao¹  Yale Liu¹  Jingang An¹  Tian Li² 

[1] Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi’an Jiaotong University, 157 Xiwu Road, Xincheng District, 710004, Xi’an, Shaanxi Province, People’s Republic of China;Department of Dermatology, Xijing Hospital, Fourth Military Medical University, 710032, Xi’an, Shaanxi, People’s Republic of China;

关键词: Rasch analysis;    Neurodermatitis;    Dermatology Life Quality Index (DLQI);   

DOI  :  10.1186/s12955-016-0419-5

 received in 2015-09-16, accepted in 2016-01-27,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe Dermatology Life Quality Index (DLQI) is the most widely used measure of health-related quality of life (HRQoL) associated with skin disease. Recently, the psychometric properties of the DLQI have caused some controversy because the instrument appears not to meet the requirements of modern test theory. The purpose of this study was to assess whether these psychometric issues also occur in Chinese patients with neurodermatitis.MethodsOne hundred fifty consecutive outpatients (83 males and 67 females) seeking treatment for neurodermatitis were assessed for eligibility for this prospective study between July 1, 2011 and September 30, 2011. The DLQI and a demographic questionnaire were completed. One female participant who incompletely answered the DLQI was excluded. Data were analyzed using the Rasch model in order to obtain meaningful scores for the DLQI. Scale assessment included analysis of rating scale function, item fit to the Rasch model, aspects of person-response validity, unidimensionality, person-separation reliability, and differential item function.ResultsThe rating scale advanced monotonically for all items in the DLQI, but item 9 did not demonstrate acceptable goodness-of-fit (Infit MnSq values >1.3) to the Rasch model. The 10 items of the DLQI met the criteria for person-separation reliability (PSI = 2.38) and the first latent dimension (general QoL) accounted for 50.8 % of the variance; but the variance explained by the second dimension (7.1 %) exceeded the criterion of 5 %. There were also limitations related to person-response validity, because ≥ 5 % (18.1 %) of cases demonstrated unacceptable fit. There was no uniform differential item functioning.ConclusionsFor neurodermatitis patients, the DLQI seems to have poor fit to the Rasch model; therefore, we recommend against using this instrument with neurodermatitis patients.

【 授权许可】

CC BY   
© Liu et al. 2016