A parent-child dyad approach to the assessment of health status and health-related quality of life in children with asthma.

BACKGROUND: Assessment of health state and health-related quality of life (HR-QOL) are limited by a child's age and cognitive ability. Parent-proxy reports are known to differ from children's reports. Simultaneous assessment using a parent-child dyad is an alternative approach.
OBJECTIVE: Our objective was to assess the validity, reliability and responsiveness of a parent-child dyad approach to utility and HR-QOL assessment of paediatric asthma health states.
METHODS: The setting was specialist care in a hospital-based asthma clinic. Participants were 91 girls and boys with asthma aged 8 to 17 years and 91 parents. The intervention employed was parent-child dyad administration of the Health Utilities Index (HUI) 2 and 3, the Pediatric Quality of Life Inventory™ (PedsQL™) Core and Asthma modules, and the Pediatric Asthma Quality of Life Questionnaire (PAQLQ). Questionnaires were administered by interview to children and parents separately and then together as a dyad to assess the child's health state. The dyad interview was repeated at the next clinic visit. Dyad-child agreement was measured by intra-class correlation (ICC) coefficient; Spearman correlations were used to assess convergent validity. Test-retest reliability was assessed in 28 children who remained clinically stable between visits with a two-way ICC coefficient. Responsiveness to change from baseline was assessed with Spearman coefficients in 30 children who demonstrated clinical change between visits.
RESULTS: There was no significant agreement between parent and child for the HUI2 or HUI3 whereas agreement between dyad and child was 0.55 (95% confidence interval [CI] 0.36, 0.69) for the HUI2 and 0.74 (95% CI 0.61, 0.82) for the HUI3 overall. With respect to dyad performance characteristics, both HUI2 and HUI3 overall scores demonstrated moderate convergent validity with the generic PedsQL™ Core domains (range r = 0.30-0.52; p < 0.01). Dyad HUI2 attributes demonstrated moderate convergent validity with the generic PedsQL™ Core domains of similar constructs (range r = 0.35-0.43; p < 0.001) and weaker convergent validity with disease-specific domains (range r = 0.13-0.32). Dyad HUI3 attributes demonstrated weaker convergent validity compared with the HUI2. For the assessment of test-retest reliability, significant agreement between baseline and follow-up was observed for dyad HUI2 total (r = 0.53), dyad PedsQL™ Core summary (r = 0.70) and select dyad disease-specific domains. Significant responsiveness (r > 0.4; p < 0.05) was observed for dyad HUI2 total score change over time as correlated with dyad HUI3, dyad PedsQL™ Core summary and select disease-specific domains.
CONCLUSIONS: The parent-child dyad approach demonstrated moderate to strong performance characteristics in generic and disease-specific questionnaires suggesting it may be a valuable alternative to relying on parent proxies for assessing children's utility and HR-QOL. Future research in additional paediatric populations, younger children and a population-based sample would be useful.