IDQoL, CDLQI and the 45-item CADIS received a sufficient content validity rating during the HOME VII meeting in Japan: a group discussion study

Abstract

Background: The Harmonising Outcome Measures for Eczema (HOME) initiative has agreed that quality of life should be measured in all atopic eczema clinical trials. Various candidate instruments exist for this domain but their content validity in atopic eczema is largely unclear. Objective: To assess the content validity of quality-of-life candidate instruments for atopic eczema in infants, children and adults in order to aid the decision on what instrument to include in the core outcome set for the quality-of-life domain. Methods: Six group discussions were conducted at the HOME VII Meeting in Tokyo. Each group was composed of 8–12 patients or parents of patients, clinicians, methodologists and pharmaceutical industry delegates and discussed one or two candidate instruments. The COSMIN criteria on relevance, comprehensiveness and comprehensibility were used to determine the overall content validity rating per instrument. Results: Content validity of the Infant's Dermatitis Quality of Life Index, Children's Dermatology Life Quality Index and the Childhood Atopic Dermatitis Impact Scale (CADIS) long-form was rated as sufficient (+). Results for the CADIS short-form, DLQI and Skindex were inconsistent (±). DISABKIDS, Infants and Toddlers Dermatology Quality of Life and ABS-A were classified as having insufficient content validity. Conclusions: The content validity rating allowed for a comparison of all candidate instruments and informed the consensus-seeking process regarding the core instrument for the quality-of-life domain.