57 research outputs found
Deriving a preference-based utility measure for cancer patients from the European Organisation for the Research and Treatment of Cancer's Quality of Life Questionnaire C30: a confirmatory versus exploratory approach
Background: Multi attribute utility instruments (MAUIs) are preference-based measures that
comprise a health state classification system (HSCS) and a scoring algorithm that assigns a utility
value to each health state in the HSCS. When developing a MAUI from a health-related quality
of life (HRQOL) questionnaire, first a HSCS must be derived. This typically involves selecting
a subset of domains and items because HRQOL questionnaires typically have too many items
to be amendable to the valuation task required to develop the scoring algorithm for a MAUI.
Currently, exploratory factor analysis (EFA) followed by Rasch analysis is recommended for
deriving a MAUI from a HRQOL measure.
Aim: To determine whether confirmatory factor analysis (CFA) is more appropriate and efficient
than EFA to derive a HSCS from the European Organisation for the Research and Treatment
of Cancer’s core HRQOL questionnaire, Quality of Life Questionnaire (QLQ-C30), given its
well-established domain structure.
Methods: QLQ-C30 (Version 3) data were collected from 356 patients receiving palliative
radiotherapy for recurrent/metastatic cancer (various primary sites). The dimensional structure
of the QLQ-C30 was tested with EFA and CFA, the latter informed by the established QLQC30
structure and views of both patients and clinicians on which are the most relevant items.
Dimensions determined by EFA or CFA were then subjected to Rasch analysis.
Results: CFA results generally supported the proposed QLQ-C30 structure (comparative fit
index =0.99, Tucker–Lewis index =0.99, root mean square error of approximation =0.04). EFA
revealed fewer factors and some items cross-loaded on multiple factors. Further assessment
of dimensionality with Rasch analysis allowed better alignment of the EFA dimensions with
those detected by CFA.
Conclusion: CFA was more appropriate and efficient than EFA in producing clinically interpretable
results for the HSCS for a proposed new cancer-specific MAUI. Our findings suggest
that CFA should be recommended generally when deriving a preference-based measure from a
HRQOL measure that has an established domain structure
Erratum to: Using a discrete choice experiment to value the QLU-C10D: feasibility and sensitivity to presentation format.
© 2017, Springer International Publishing Switzerland. In this article by R. Norman et al., the article by M. T. King et al. is cited as Reference 10, as ‘Submitted’ and ‘Under Review’. However, the Reference 10 should appear with year, volume and page numbers as: King et al., Quality of Life Research (2016); 25(3):625-636. Also an error was found in Table 1 in the reported wording of the Physical Functioning item. The error and correction are described below. The error was limited to Table 1. The survey described in the paper used the correct labelling, and the validity of the analysis is therefore unaffected by the error
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