Factor structure, reliability, inter-rater agreement and convergent validity of the parent and child Italian versions of the paediatric quality of life inventory multidimensional fatigue scale for children and adolescents in paediatric inpatients with obesity and their parents

Objective: This study aimed to examine the factor structure, reliability, inter-rater agreement and convergent validity of the child and parent Italian versions of the paediatric quality of life inventory multidimensional fatigue scale (PedsQL-MFS) in paediatric inpatients with obesity and one of their parents. Methods: 100 pairs of children/adolescents (64% female, mean age = 15.34) with obesity and one of their parents completed the PedsQL-MFS and the Child Behaviour Checklist (CBCL) or the Youth Self Report. Results: Confirmatory Factor Analysis indicated that the three correlated first-order factors model corresponding to the published subscales demonstrated acceptable fit and achieved strict invariance across parent and child informants. Bifactor Analysis supported the multidimensionality and the reliability of the total and subscale scores as multidimensional composites. Parent–child agreement was low with latent means higher for parent reports. PedsQL-MFS total scores were strongly correlated with Somatic Complaints scores on the CBCL, and moderately associated with anxiety, depression, social problems and school problems. Conclusions: Total scores of the child and parent Italian versions of the PedsQL-MFS demonstrated good reliability and convergent validity in paediatric inpatients with obesity and their parents, and are complementary rather than interchangeable. Level of evidence: No level of evidence.