Health and Quality of Life Outcomes (Apr 2020)

Validation of the Chinese EORTC chronic lymphocytic leukaemia module – application of classical test theory and item response theory

  • Dong Dong,
  • Jun Jin,
  • Simone Oerlemans,
  • Siyue Yu,
  • Shenmiao Yang,
  • Jianfeng Zhu,
  • Richard Huan Xu

DOI
https://doi.org/10.1186/s12955-020-01341-z
Journal volume & issue
Vol. 18, no. 1
pp. 1 – 13

Abstract

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Abstract Purpose The association of chronic lymphocytic leukemia (CLL) with health-related quality of life (HRQoL) is rarely studied globally. This study evaluated the psychometric properties of the EORTC-Chronic Lymphocytic Leukaemia (CLL17 [phase III]) module, a newly developed assessment on CLL patients’ HRQoL, among Chinese CLL patients. Methods The Chinese CLL17, comprised of three subscales (symptom burden [SB], physical condition [PC] and worries/fears [WF]), was provided by the developer team through EORTC. A cross-sectional online survey was conducted to collect data. The classical traditional theory (CTT) and the item response theory (IRT) were used to evaluate the psychometric properties of CLL17. Internal consistency reliability was determined by the Cronbach’s alpha and item-total correlation. Dimensionality was verified through confirmatory factor analysis (CFA). Convergent validity was also assessed. The generalized partial credit model was used for the IRT. The difficulty, discrimination, item fit, and differential item functioning (DIF) were calculated to assess the instrument’s psychometric properties. Results In all, 318 patients, aged between 26 and 82 years, completed the questionnaire. A good level of internal reliability was achieved (Cronbach’s alpha = 0.92). The item-total correlation coefficient ranged from 0.46 to 0.72. There was a mid-to-high correlation between CLL17 and domains of EQ-5D and QLQ-C30. The IRT model showed a satisfactory homogeneity, item fit and good discrimination of items, except for item 4, 6 and 16 ( 0, whereas WF provided more information with theta < 0. Item 17 perform inconsistently for respondents from different age groups (DIF). Conclusion The EORTC-CLL17 Chinese version shows acceptable reliability and validity, making it a valuable instrument to evaluate the impact on the HRQoL of Chinese CLL patients.

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