OHE and the University of Technology Sydney are leading a study funded by the EuroQol Research Foundation to develop a ‘bolt-on’ descriptor for the EQ-5D. The goal is to develop and test new questions that can be used with people who have hearing impairments. We’re currently seeking research participants.

The EQ-5D descriptive system forms the basis of a questionnaire that is widely used in health research. In particular, the EQ-5D is used to estimate quality-adjusted life years (QALYs), which are the cornerstone of value in health technology assessment in the UK and elsewhere. However, in certain circumstances, the EQ-5D has been shown to perform less well than other measures of health outcome. In particular, the EQ-5D sometimes does not detect meaningful changes in hearing. This has led some researchers to call for the development of ‘bolt-on’ items, which would be additional aspects of health added to the core set of five EQ-5D domains (mobility, self-care, usual activities, pain/discomfort, anxiety/depression). The EuroQol Group is keen to explore the development of bolt-ons, though it is not committed to expanding the EQ-5D at this stage.

In collaboration with the University of Technology Sydney, the University of Oxford, and Maths in Health, we have been funded by the EuroQol Research Foundation to develop bolt-on descriptors for hearing. Researchers are increasingly recognising the need for health outcome measurement to be patient-centred, which means that the development of new measures should be informed by the views of people who will ultimately be asked to complete the questionnaires. To this end, our work will employ both qualitative and quantitative research methods to develop candidate bolt-ons. The project is organised into three phases.

Phase 1: Development of descriptors

In the first part of the study, we will generate a set of possible descriptors that might make for suitable bolt-on items. One input to this process is a systematic literature review of qualitative evidence, ensuring we make the most of previous research on the impact of hearing on people’s quality of life. Following the review, we will conduct a series of online discussion groups to better understand lived experiences of hearing impairments. Through this, we aim to ensure that the resulting bolt-on captures aspects of health that are considered most relevant in a way that is meaningful to people completing the measures. The groundwork of the literature review will guide a set of discussion groups, which we will be conducting in the UK in the form of online discussion forums and a video focus group for British Sign Language (BSL) users. Participants will have varying degrees of impairment and will be asked to discuss the ways in which hearing impairment affects their quality of life and how they would describe that.

Phase 2: Qualitative testing

Based on the findings from Phase 1, we’ll conduct a series of interviews with people who have lived experience of hearing impairment. We’ll ask participants to complete EQ-5D-5L questionnaires with candidate bolt-on descriptors, followed by cognitive debriefing. This will help us to understand potential difficulties with comprehensibility or accessibility.

Phase 3: Quantitative testing

Once we have a set of possible bolt-on descriptors, they will be subject to psychometric testing. This will involve a cross-sectional survey conducted online, which will ask participants to complete the EQ-5D-5L questionnaire with candidate bolt-on items and other condition-specific instruments. The analysis will include descriptive analysis, classical psychometric analysis, convergent and discriminant validity, factor analysis, and regressions. Item response theory and Rasch analysis will also be used to compare the performance of candidate hearing bolt-on items. 

Get involved

We are currently conducting Phase 1 of the study and are looking for participants to take part in online discussion groups and interviews. If you have experienced hearing impairment, are over 18 and live in the UK, please consider volunteering your time to our research. To sign up to participate, please complete the forms on our project website, where you will also find BSL versions of our recruitment information.

If you are a researcher, you can follow the progress of our project on ResearchGate.

For more information about the study, please visit our website or contact the project team here.

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