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

Abstract

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