Use of rasch methodology to develop a short version of the Health Related Quality of life for Eating Disorders questionnaire: a prospective study

Abstract

BackgroundTo confirm the internal structure of the Health Related Quality of Life for Eating Disorders version 2 questionnaire (HeRQoLEDv2) and create and validate a shortened version (HeRQoLED-S).Methods324 patients with eating disorders were assessed at baseline and one year later (75.6% of whom responded). We performed a confirmatory factor analysis of the HeRQoLEDv2 using baseline data, and then a Rasch analysis to shorten the questionnaire. Data obtained at year one was used to confirm the structure of the HeRQoLED short form and evaluate its validity and reliability.ResultsTwo latent second-order factors -- social maladjustment and mental health and functionality -- fit the data for the HeRQoLEDv2. Rasch analysis was computed separately for the two latent second-order factors and shortened the HeRQoLEDv2 to 20 items. Infit and outfit indices were acceptable, with the confirmatory factor analysis of the HeRQoLED short form giving a root mean square error of approximation of 0.07, a non-normed fit index and a comparative fit index exceeding 0.90. The validity was also supported by the correlation with the convergent measures: the social maladjustment factor correlated 0.82 with the dieting concern factor of the Eating Attitudes Test-26 and the mental health and functionality factor correlated -0.69 with the mental summary component of the Short Form-12. Cronbach alphas exceeded 0.89.ConclusionsTwo main factors, social maladjustment and mental health and functionality, explain the majority of HeRQoLEDv2 scores. The shortened version maintains good psychometric properties, though it must be validated in independent samples.

Quality of life among caregivers of patients with eating disorders

“…Patients' quality of life was evaluated using the HealthRelated Quality of Life in ED-short form (HeRQoLED-s), which is intended to assess the impact of an ED on the patient's physical, mental and social domains [34,35]. It consists of 20 items distributed into two domains: social maladjustment (SocM) and mental and functional health (MFH).…”

Cross-Validation Study Using Item Response Theory

“…The HeRQoLED-S, the focus of this study, is a specific self-administered questionnaire, developed in Spanish, which is intended to assess the impact of EDs on patient physical, psychological, and social functioning (Las Hayas et al, 2010). It consists of 20 items covering two areas: SocM and MHF.…”

“…Regarding construct validity, first, the two-factor second-order internal structure of the HeRQoLED-S was tested using confirmatory factor analysis (CFA) for categorical variables. The structural and measurement model hypothesized for the short form was the same as that of the long version, the only difference being that fewer items were assigned to each first-order factor (Las Hayas et al, 2010). Besides, the one-factor second-order structure was also examined.…”

“…Accordingly, with the 40 items composing the seven other factors, first the internal structure of the questionnaire was confirmed showing two second-order latent traits: "social maladjustment" (SocM) and "mental health and functionality" (MHF). These summary measures were subjected to Rasch analysis, and finally the HeRQoLED short form (HeRQoLED-S) was derived comprising 20 items (Las Hayas et al, 2010). Both the confirmation of the second-order internal structure and the reduction of the HeRQoLED questionnaire were carried out with the same sample of 324 ED patients used for the development and validation processes of the original questionnaire.…”

“…A first validity study of the HeRQoLED-S was performed using the follow-up sample from the original sample 1 year after initial assessment, and this indicated that the reduced questionnaire was valid and reliable (Las Hayas et al, 2010); however, this first validation of the HeRQoLED-S was limited in that the same sample had been used both for the development as for the confirmation of its structure. It is recommended to use new and independent samples for psychometric studies of short forms of questionnaires (in particular regarding the construct validity and reliability; Coste et al, 1997), but in our case this was not possible given financial limitations and the difficulty of obtaining large samples in these patients, and consequently, we used the follow-up sample.…”