Objective: The aim of this study was to validate the newly developed shortened Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) in a sample of children with drug-resistant epilepsy.
Methods: Data came from 136 children enrolled in the Impact of Pediatric Epilepsy Surgery on Health-Related Quality of Life Study (PEPSQOL), a multicenter prospective cohort study. Confirmatory factor analysis was used to assess the higher-order factor structure of the QOLCE-55. Convergent and divergent validity was assessed by correlating subscales of the KIDSCREEN-27 with the QOLCE-55. Measurement equivalence of the QOLCE-55 was evaluated using multiple-group confirmatory factor analysis of children with drug-resistant epilepsy from PEPSQOL versus children with new-onset epilepsy from HERQULES (Health-Related Quality of Life in Children with Epilepsy Study).
Results: The higher-order factor structure of the QOLCE-55 demonstrated adequate fit: Comparative Fit Index (CFI) = 0.948; Tucker-Lewis Index (TLI) = 0.946; Root Mean Square of Approximation (RMSEA) = 0.060 (90% confidence interval [CI] 0.054-0.065); Weighted Root Mean Square Residuals (WRMR) = 1.247. Higher-order factor loadings were strong, ranging from λ = 0.74 to 0.81. Internal consistency reliability was excellent (α = 0.97, subscales α > 0.82). QOLCE-55 subscales demonstrated moderate to strong correlations with similar subscales of the KIDSCREEN-27 (ρ = 0.43-0.75) and weak to moderate correlations with dissimilar subscales (ρ = 0.25-0.42). The QOLCE-55 demonstrated partial measurement equivalence at the level of strict invariance - χ2 (2,823) = 3,727.9, CFI = 0.961, TLI = 0.962, RMSEA = 0.049 (0.044, 0.053), WRMR = 1.834.
Significance: The findings provide support for the factor structure of the QOLCE-55 and contribute to its robust psychometric profile as a reliable and valid measure. Researchers and health practitioners should consider the QOLCE-55 as a viable option for reducing respondent burden when assessing health-related quality of life in children with epilepsy.
Keywords: Factor analysis; Health-related quality of life; Measurement equivalence; Pediatric epilepsy; Validity.
Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.