Psychometric evaluation of the traditional Chinese version of PedsQL(™) 3.0 cardiac module scale in adolescents with congenital heart disease: reliability, validity, measurement invariance, and adolescent-parent agreement

BACKGROUND: In recent decades, 95% of children with congenital heart disease (CHD) can survive to adolescence and adulthood. However, adolescents with CHD are prone to poorer health-related quality of life (HRQoL). It is imperative to develop a reliable and valid instrument for health professionals to monitor the HRQoL. This study aims to: (1) evaluate the psychometric properties of the traditional Chinese version of Pediatric Quality of Life™ 3.0 Cardiac Module (PedsQL-CM) and measurement invariance across adolescents with CHD and their parents; and (2) investigate the adolescent-parent agreement in HRQoL. METHODS: A total of 162 adolescents and 162 parents were recruited. Internal consistency was examined using Cronbach’s alpha and McDonald’s Omega. The criterion-related validity was evaluated with intercorrelations between the PedsQL-CM and PedsQL™ 4.0 Generic Core (PedsQL-GC) Scale. The construct validity was examined by second-order confirmatory factor analysis (CFA). Measurement invariance was evaluated using the multi-group CFA. The adolescent-parent agreement was analyzed with the intraclass correlation (ICC), paired t-tests, and Bland–Altman plots. RESULTS: PedsQL-CM showed acceptable internal consistency (self-reports 0.88, proxy-reports 0.91). The intercorrelations were medium to large effect size (self-reports 0.34–0.77, proxy-reports 0.46–0.68). The CFA supported the construct validity (CFI = 0.967, TLI = 0.963, RMSEA = 0.036, 90% CI = 0.026–0.046, SRMR = 0.065). The multi-group CFA proved scalar invariance between self and parent proxy-reports. Parents significantly underestimated their adolescents’ HRQoL in cognitive problems (Cohen’s d = 0.21) and communication (Cohen’s d = 0.23) subscales, while there was a negligible difference in total HRQoL (Cohen’s d = 0.16). ICCs were poor to moderate effect size with the highest and lowest agreement in heart problems and treatment subscale (ICC = 0.70) and communication subscale (ICC = 0.27), respectively. The Bland–Altman plots showed lesser variability in the heart problem and treatment subscale and the total scale. CONCLUSION: The traditional Chinese version of PedsQL-CM has acceptable psychometric properties to measure disease-specific HRQoL in adolescents with CHD. Parents may be proxies for adolescents with CHD to rate total HRQoL. When the patient-reported score is the primary outcome, the proxy-reported score could serve as a secondary outcome for research and clinical evaluation.