AB023. Validity of the EQ-5D-Youth in asthmatic children

Background: Health-related quality of life (HRQOL) assessment in children and adolescents is an increasing area of interest in public health research and in daily clinical practice. EQ-5D-Y is a variant of the EQ-5D instrument developed by the EuroQol group for use in children and adolescents from 8 to 18 years of age. It has demonstrated its feasibility, reliability, and validity but up to date, metric properties of EQ-5D-Y have not been assessed in children with asthma. The aim of this study is to examine distribution, content and construct validity of the EQ-5D-Y in a European sample of asthmatic children.

Methods: A subsample of 69 children with asthma (6–11 years) included in the ASTROLAB cohort who completed EQ-5D-Y via online questionnaire was analysed. The EQ-5D-Y is a brief, multi-attribute, generic, preference-based health status measure consisting of five dimensions with three response levels. Index values were calculated using the EQ-5D-3L preference value sets for France, which ranges from 1 (best health possible) to −0.594 (negative values indicate health state worse than death). To examine the distribution of the index measures, we calculated measures of central tendency, dispersion, proportion of children with perfect health, and observed range. Construct validity was assessed by comparing means of known groups defined by the Royal College of Physicians 3 Questions (RCP3Q) for children, that measures the presence of asthma symptoms in the last month in 3 Likert scale response options, with a score ranging from 0 to 9 (lower score better asthma control). Two groups of asthma control were defined: well-controlled (RCP3Q 0–1), and not well-controlled (RCP3Q >1). Mean scores were compared among groups with ANOVA. The magnitude of the difference was measured by effect size (ES) coefficient calculated as the difference in mean scores between groups/pooled standard deviation.

Results: Mean EQ-5D-Y index was 0.878 (0.211). The observed range was −0.12 to 1. Floor and ceiling effects were 0% and 50%, respectively. Almost all children reported ‘no problems’ in Mobility and Self-care dimensions. It is noteworthy that >20% of children reported problems in Everyday activities, Pain/discomfort and Happiness/worry/sadness. Mean EQ-5D-Y index for children with well-controlled asthma was 0.94 (95% CI, 0.91 to 0.96); and 0.82 (95% CI, 0.72 to 0.91) for patients not well-controlled. These indexes were significantly different (P=0.015), and the effect size between both groups was moderate (ES: 0.6).

Conclusions: The new EQ-5D-Y provided an adequate pattern of distribution among domains supporting content validity despite the index ceiling effect was considerable. The relevant difference between known asthma control groups indicates good construct validity for assessing health related quality of life in these children.

Keywords: EQ-5D-Youth; asthmatic children; health related quality of life (HRQOL); distribution; construct validity