Practicality, validity and responsiveness of using the proxy version of the CHU-9D with children aged 2 to 5 years

OBJECTIVES: To assess the practicality, validity and responsiveness of proxy CHU-9D in children aged 2-5 years. METHODS: We used data from BEEP, a UK randomised controlled trial testing whether daily emollients in infancy could prevent eczema in high-risk infants. The main parent/carer completed the proxy CHU-9D using developers' additional guidance for completion in under-5's and the Patient-Orientated Eczema Measure (POEM) at ages 2, 3, 4 and 5. Practicality was assessed by completion rates. Construct validity assessed if CHU-9D could discriminate between those with/without eczema and between eczema severity levels on POEM. Responsiveness was determined by ability to discriminate between three groups: those whose POEM score, i) deteriorated ≥3 points, ii) change not clinically important (-2.9 to 2.9 points), and iii) improved ≥3 points. Analysis was conducted in STATA 17. RESULTS: Of 1,394 children participating in BEEP, study questionnaires were completed by 1,212 (87%), 981 (70%), 990 (71%), and 976 (70%) at 2, 3, 4 and 5-years. Of these the CHU-9D was completed by 1,066 (88.0%), 685 (69.8%), 925 (93.4%) and 923 (94.6%) respectively. Mean utility at all timepoints was around 0.934 (range 0.443-1). For construct validity, very small differences on the CHU-9D between known groups were observed(p <0.01). 801 participants had responsiveness data: 13% deteriorated, 72% had non-clinically important change, and 15% improved. Mean utility change (standardised response mean) for these groups was -0.0198 (0.21), 0.0041 (0.05), and 0.0175 (0.21)showing small change and small responsiveness. CONCLUSIONS: Proxy CHU-9D in 2-5 year old children shows potential but further research is needed.