Development and assessment of a shortened Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55)

Abstract

Objective: To develop and validate a shortened version of the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE). A secondary aim was to compare baseline risk factors predicting health-related quality of life (HRQoL) in children newly diagnosed with epilepsy, as identified using the original and shortened version.

Methods: Data came from the Health-Related Quality of Life in Children with Epilepsy Study (HERQULES, N = 373), a multicenter prospective cohort study. Principal component analysis reduced the number of items from the original QOLCE, and factor analysis was used to assess the factor structure of the shortened version. Convergent and divergent validity was assessed by correlating the Child Health Questionnaire (CHQ) with the shortened QOLCE. Multiple regression identified risk factors at diagnosis for HRQoL at 24 months.

Results: A four-factor, higher-order, 55-item solution was obtained. A total of 21 items were removed. The final model represents functioning in four dimensions of HRQoL: Cognitive, Emotional, Social, and Physical. The shortened QOLCE demonstrated acceptable fit: Bentler's Comparative Fit Index = 0.944; Tucker-Lewis Index = 0.942; root mean square approximation = 0.058 (90% CI: 0.056-0.061); weighted root mean square residuals (WRMR) = 1.582, and excellent internal consistency (α = 0.96, subscales α > 0.80). Factor loadings were good (first-order: λ = 0.66-0.93; higher-order λ = 0.66-0.85; p < 0.001 for all). The shortened QOLCE scores correlated strongly with similar subscales of the Child Health Questionnaire (ρ = 0.38-0.70) while correlating weakly with dissimilar subscales (ρ = 0.30-0.31). While controlling for HRQoL at diagnosis, predictors for better HRQoL at 24 months were the following: no cognitive problems reported (p = 0.001), better family functioning (p = 0.014), fewer family demands (p = 0.008), with an interaction between baseline HRQoL and cognitive problems (p = 0.011).

Significance: Results offer initial evidence regarding reliability and validity of the proposed 55-item shortened version of the QOLCE (QOLCE-55). The QOLCE-55 produced results on risk factors consistent with those found using the original measure. Given the fewer items, QOLCE-55 may be a viable option reducing respondent burden when assessing HRQoL in children with epilepsy.

Keywords: Children; Confirmatory factor analysis; Epilepsy; Health-related quality of life; Measurement; Psychometrics; Quality of Life in Childhood Epilepsy Questionnaire (QOLCE).