QLU-C10D Measurement Properties: A Comparison with EQ-5D-5L

This study demonstrates the strong measurement properties of the QLU-C10D questionnaire. The C10D dimensions exhibited lower ceiling effects compared to the 5L dimensions, suggesting a more balanced design. Furthermore, C10D exhibited a wider structural breadth compared to 5L. Interestingly, even individuals deemed healthy according to the EQ-5D-5L reported issues when assessed using disease-specific measurements. Among the 5L respondents, 25 patients selected '1111', whereas only 17 patients chose the same response in C10D (Table 3). Notably, the dimensions of Physical, Social, and Fatigue displayed more problems in C10D. Unlike the study conducted by Norma B. Bulamu et al., this study also observed discrepancies in the results generated by the two scales within the Physical dimension. This can be attributed to the inclusion of additional content from 5L in the Physical dimension of C10D, encompassing mobility, self-care, and usual activities. Consequently, there exists substantial content overlap between these two scales. This is supported by our convergent validity results, which demonstrate higher correlations between theoretically corresponding domains and an overall strong association between the index scores.