Psychometric Evaluation of the Proxy-Reported Pediatric Quality of Life Inventory Generic Core Scales Across the Childhood Lifespan in Australian Children and Adolescents With Specified Health Conditions

Objectives Current generic childhood health-related quality-of-life instruments lack comprehensive psychometric evidence across all ages. The Pediatric Quality-of-Life Inventory v4.0 Generic Core Scales (PedsQL GCS) covers ages 2 to 18 years old, but evidence on its psychometric properties is limited to restricted age groups. This study aimed to evaluate the proxy-reported PedsQL GCS across the entire childhood lifespan. Methods The study used data from the Longitudinal Study of Australian Children for children aged 2 to 17 years with 1 of 6 health conditions: high weight status, eczema, attention deficit hyperactivity disorder, vision problems, hearing problems, and learning difficulty. Psychometric properties of the proxy-reported PedsQL GCS were assessed in early childhood, middle childhood, and adolescence against established criteria. Results In analyses of 9317 children with 50 934 total observations, the PedsQL GCS demonstrated good acceptability across the childhood lifespan, except for high rates of missing data in 2 to 9 year olds (range = 12%-30%). Strong internal consistency was evident across health conditions and age (α range = 0.72-0.93; item-total correlations range = 0.28-0.80). Known group validity was strong with differentiation between children with/without the condition across all ages, except for eczema. Responsiveness was variable with inconsistencies mainly in early childhood. Conclusions This study adds to the PedsQL psychometric evidence base, finding that the proxy-reported PedsQL GCS demonstrated robust reliability and known group validity, good acceptability, and mixed responsiveness in Australian children with health conditions across age. We propose the PedsQL GCS as a robust instrument to take forward for valuation to directly generate utility values for use in economic evaluations.