Development of a health state classification system for the PedsQL™ 4.0 Generic Core Scales for preference-based valuation in Australia.
Kwon J., Raghunandan R., Nghiem SH., Howard K., Lancsar E., Huynh E., Howell M., Petrou S., Smith S.
OBJECTIVES: Pediatric Quality of Life InventoryTM Version 4.0 Generic Core Scales (PedsQL GCS), comprising 23 items covering four sub-scales (physical, emotional, social, and school functioning), is a widely applied generic measure of childhood health-related quality of life, but does not provide health utilities for cost-effectiveness-based decision-making. This study aimed to develop a reduced item version of PedsQL GCS amenable to health utility derivation in Australia. METHODS: Data sources were two cohorts of the Longitudinal Study of Australian Children, including proxy responses for all PedsQL GCS versions (Toddlers, Young Children, Children, Teens), and the CheckPoint sample containing child self-report to the Children version. Three analytic samples were: CheckPoint sample (n=1,874); Mallinson sample containing one measurement per child from one of the Young Children, Children or Teens versions (n=7,855); and Toddlers sample (n=7,401). Exploratory and confirmatory factor analyses assessed dimensionality. Psychometric analyses used Rasch and classical criteria on three randomly selected subsamples (n=500) per sample. Item selection prioritised psychometric performance in CheckPoint sample, also considering performance in other samples and conceptual content. RESULTS: Dimensionality assessments did not generate an alternative empirical structure for the measure, and psychometric analyses were conducted on the original four sub-scales. The selected items were: 'Get aches and pains' for physical functioning; 'Feel sad/blue' for emotional functioning; 'Other kids not friends' for social functioning; and 'Keeping up with school work' for school functioning. CONCLUSIONS: The final four-item set, pending further psychometric validation and valuation, can generate health utilities from the widely used PedsQL GCS to inform cost-effectiveness-based decision-making.