OBJECTIVES

Evidence suggests that, in specific circumstances, the EQ-5D is insensitive to changes or differences in health status. One possible solution is to add 'bolt-on' dimensions to the core EQ-5D dimensions, to provide additional information about the impact of certain conditions or symptoms on health. In this study, we developed EQ-5D-5L bolt-ons for cognition (5L-Cog) and vision (5L-Vis).

METHODS

The development process involved three stages. First, systematic literature reviews were conducted for outcome measures used in cognitive impairment and visual impairment. Items were extracted from existing measures and mapped to a set of dimensions. Common terminology was also recorded. Second, we conducted focus groups in the UK with people who have experience of either impairment. Participants were encouraged to describe the impact of their own experience of cognitive impairment or visual impairment, with reference to dimensions and terminologies identified in the literature reviews. The findings were used to develop candidate 5L-Cog and 5L-Vis descriptors. Third, we conducted interviews in the UK and Australia with people who have experience of either impairment. Interviewees were asked to complete the EQ-5D-5L with candidate 5L-Cog or 5L-Vis descriptors, followed by cognitive debriefing.

RESULTS

Candidate descriptors related to dimensions such as memory (for 5L-Cog), visual acuity (for 5L-Vis), mood (for both), and social functioning (for both). Various terminologies were identified in the review, with 'problems', 'limitations', 'difficulties', and 'feelings' being used in both contexts. Focus group participants expressed preferences for different terms and identified problematic words.

CONCLUSIONS

Qualitative research methods can be used to develop bolt-on descriptors for the EQ-5D that are meaningful to people with lived experience. However, it is challenging to identify a suitable range of participants where people with relevant lived experience constitute a heterogeneous population. In a subsequent phase of the study, 5L-Cog and 5L-Vis descriptors will be tested quantitatively.