Reliability and validity of the Iranian version of the Pediatric Quality of Life Inventory™ 4.0 Generic Core Scales in adolescents

Abstract

Objective: The objective of this study was to investigate the reliability and validity of the Iranian version of the Pediatric Quality of Life Inventory™ 4.0 (PedsQL™ 4.0) Generic Core Scales in adolescents

Methods: After linguistic validation, the Iranian version of the PedsQL™ 4.0 was completed by 848 healthy and 26 chronically ill adolescents aged 13-18 years and their parents.

Results: The internal consistency as measured by Cronbach's alpha coefficients exceeded the minimum reliability standard of .70. No floor effects were observed. Ceiling effects detected ranged from 1.5% for adolescent self-report total scale score to 42.2% for self-report social functioning. All monotrait-multimethod correlations were higher than multitrait-multimethod correlations. The intraclass correlation coefficients (ICC) between adolescent self-report and parent proxy-report showed good to excellent agreement. Exploratory factor analysis supported mainly comparable results with the original US English dialect version. The results of the confirmatory factor analysis for 5-factor models for both self-report and proxy-report indicated acceptable fit for the proposed models. Regarding gender and health status, as hypothesized from previous studies, girls reported lower health-related quality of life than boys on the total score, physical and emotional functioning, and healthy adolescents reported significantly higher health-related quality of life than those with chronic illnesses.

Conclusion: The findings support the initial reliability and validity of the Iranian version of the PedsQL™ 4.0 as a generic instrument to measure HRQOL of adolescents in Iran.