Psychometric properties of the Children's Dermatology Life Quality Index in pediatric localized scleroderma.
INTRODUCTION: The Children's Dermatology Life Quality Index has been used to measure quality of life in studies of pediatric localized scleroderma, which suggested only modest effects on quality of life. However, the Children's Dermatology Life Quality Index psychometric performance has not been examined in localized scleroderma and it was validated in populations lacking localized scleroderma's distinctive clinical features, possibly underestimating the quality of life impact. This study assessed psychometric properties of the Children's Dermatology Life Quality Index in a cohort of pediatric localized scleroderma patients. METHODS: Existing Children's Dermatology Life Quality Index data from a large pediatric localized scleroderma cohort were analyzed. Children's Dermatology Life Quality Index score distributions were examined and internal consistency was evaluated with Cronbach's alpha for the entire Children's Dermatology Life Quality Index and after deletion of individual items. Construct validity was assessed by calculating Spearman's correlations between Children's Dermatology Life Quality Index scores and disease severity/impact measures. Dimensionality was examined using exploratory factor analysis with sequential item elimination. RESULTS: Children's Dermatology Life Quality Index scores suggested modest adverse effects on quality of life. Internal consistency was adequate (Cronbach's alpha = 0.727) but increased after eliminating items regarding friendships, sleep, and treatment burdens. Children's Dermatology Life Quality Index scores were not associated with physician-scored disease severity measures but were moderately associated with patient/parent assessments of disease impact. Exploratory factor analysis yielded a three-factor solution encompassing functional limitations, psychosocial effects, and skin symptoms/treatment burden. CONCLUSION: The Children's Dermatology Life Quality Index may capture functional and psychosocial domains of quality of life in localized scleroderma, but likely underestimates the quality of life impact given that it includes some items with limited relevance in localized scleroderma, incompletely explores skin symptoms and treatment burdens, and demonstrates limited construct validity. Further study to optimize quality of life measurement in pediatric localized scleroderma is warranted.
