Modular update: Equality and health inequality impact assessment (EHIA)

4.3 Measuring and valuing health effects in cost-utility analyses

4.3.4 The valuation of health-related quality of life measured by patients (or their carers) should be based on a valuation of public preferences from a representative sample of the UK population using a choice-based method. This valuation leads to the calculation of utility values.

4.3.5 Different methods used to measure health-related quality of life produce different utility values. Therefore, results from different methods or instruments cannot always be compared.

4.3.6 Given the need for consistency across evaluations, the EQ-5D measurement method is preferred to measure health-related quality of life in adults. Preference values from the EQ-5D should be applied to measurements of health-related quality of life to generate health-related utility values.

4.3.9 When EQ‑5D data is not available, this data can be estimated by mapping other health-related quality-of-life measures or health-related benefits seen in the relevant clinical trials to EQ‑5D. This is considered to be a departure from the reference case. The mapping function chosen should be based on data sets containing both health-related quality-of-life measures and its statistical properties. It should be fully described, its choice justified, and it should be adequately shown how well the function fits the data. Present sensitivity analyses to explore variation in using mapping algorithms on the outputs.

4.3.10 In some circumstances the EQ‑5D may not be the most appropriate measure. To make a case that the EQ‑5D is inappropriate, provide qualitative empirical evidence on the lack of content validity for the EQ‑5D, showing that key dimensions of health are missing. This should be supported by evidence that shows that EQ‑5D performs poorly on tests of construct validity (that is, it does not perform as would be expected) and responsiveness in a particular patient population. This evidence should be derived from a synthesis of peer-reviewed literature. In these circumstances alternative health-related quality-of-life measures may be used. These must be accompanied by a carefully detailed account of the methods used to generate the data, their validity, and how these methods affect the utility values.

4.3.11 In circumstances when evidence generation is difficult (for example, for rare diseases), when there is insufficient data to assess whether the EQ‑5D adequately reflects changes in quality of life, evidence other than psychometric measures may be presented and considered to establish whether the EQ‑5D is appropriate.

4.3.12 A hierarchy of preferred health-related quality-of-life methods is presented in figure 4.1. Use figure 4.1 for guidance when the EQ‑5D is not available or not appropriate.

Figure 4.1 Hierarchy of preferred health-related quality-of-life methods