The NICE Guide to the Methods of Technology Appraisals recommends that quality adjusted life years (QALYs) are used as the measure of outcome for economic evaluation, and that the EQ-5D is the preferred measure of health-related utility to calculate QALYs. The guide also recognises that EQ-5D data may not always be available to analysts producing submissions and reports for NICE. Where such data are not available, the guide states that mapping can be used to predict EQ-5D data.
‘Mapping’ is the development and use of an algorithm (or algorithms) to predict health-state utility values using data on other indicators or measures of health. The algorithm can be applied to data from clinical trials, other studies or economic models containing the source predictive measure(s) to predict utility values even though the target preference-based measure was not included in the original source study of effectiveness. The predicted utility values can then be analysed using standard methods for trial-based analyses or summarised for each health state within an economic model.
Although the use of mapping to predict utility data has only recently been referred to within the NICE Guide to the Methods of Technology Appraisals, it has been used for several years in NICE submissions. An overview of the use of mapping in Technology Appraisals recently found that mapping had been used in over a quarter of submission to the TA programme. This support document draws on previous research to report the methods that can be used to map to EQ-5D data and draws on existing research, conducted for the NICE TA programme and the wider literature. A series of recommendations are provided for analysts considering the use of mapping to estimate health-related utility for inclusion in NICE Technology Appraisals.
Keywords: health-related quality of life; utility assessment; quality adjusted life years; mapping; EQ-5D; cost-utility analysis.
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