Methodological preparatory work for the UK EQ-5D-5L valuation study

Following the emergence of the COVID-19 pandemic, the Steering Group discussed the feasibility of undertaking the EQ-5D-5L valuation study for the United Kingdom during the COVID-19 pandemic. The question was whether the EQ-VTv2 TTO interviews could be conducted remotely using online videoconferencing software (such as Zoom or Microsoft Teams), and whether the results would be comparable with regular face-to-face interviews. Available evidence at the time suggested that experienced interviewers can do EQ-VT interviews face-to-face or remotely, with comparable results. However, none of these studies had a dedicated design to compare face-to-face versus videoconferencing in a controlled way. It was therefore decided to conduct a study to formally compare the feasibility, acceptability and equivalence of these two interviewing methods to collect TTO data (hereafter, ‘the equivalence study’), before starting the new UK valuation study. Following a delay to the start of the equivalence study, due to another lockdown in the UK, the Steering Group agreed to a proposal to run a parallel equivalence study in Australia or New Zealand, as the COVID-19 situation was different in that part of the world. Both studies were funded by EuroQol Research Foundation.

While the equivalence studies were starting, the study team and Steering Group focussed on ensuring that the protocol for the new study would address the concerns raised during the quality assurance of the Devlin et al. (2018) value set (these reviews are available on the NICE website, comprising an and reports from 4 independent experts). To this end the study team compiled a checklist summarizing the criticisms of the Devlin et al. value set and how the new study will address these criticisms – and provided rationale for any design elements that were previously criticised but that have not been changed in the new study. The statistical analysis plan was also informed by a review of published EQ-5D-5L value sets by Rowen et al. (2022).

In early 2022 Donna Rowen presented the results of the UK equivalence study. The results demonstrated that video and in-person TTO interviews are feasible and acceptable. Both interviewing modes generated good-quality data. A notable finding was that the characteristics of people preferring video interviews differed significantly from those preferring in-person interviews. Therefore, both modes will be used in the UK valuation study, with respondents being able to choose their preferred interviewing mode, to make the study more inclusive and maximise sample .

Finally, in line with Step 30 of the study governance document, the QC team has performed a
formal quality control (QC) of the study protocol and statistical analysis plan. QC findings were shared with the study team and the Steering Group, who provided their own feedback. Updates of these documents were discussed in the Steering Group. The study protocol and analysis plan were reviewed and approved for funding by EuroQol’s Executive Committee in June 2022. The Steering Group signed off on the study protocol and the statistical analysis plan in July 2022. The study protocol, including explanation of how the protocol has been designed to resolve quality assurance concerns with a previous English valuation, is being submitted for journal publication.