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Original research
Response process validity of three patient reported outcome measures for people requiring kidney care: a think-aloud study using the EQ-5D-5L, ICECAP-A and ICECAP-O
  1. Paul Mark Mitchell1,
  2. Fergus John Caskey2,3,4,
  3. Jemima Scott3,4,
  4. Sabina Sanghera1,
  5. Joanna Coast1
  1. 1Health Economics Bristol, Population Health Sciences, University of Bristol, Bristol, UK
  2. 2Population Health Sciences, University of Bristol, Bristol, UK
  3. 3UK Renal Registry, Southmead Hospital Bristol, Bristol, UK
  4. 4North Bristol NHS Trust, Southmead Hospital, Bristol, UK
  1. Correspondence to Dr Paul Mark Mitchell; paul.mitchell{at}


Objectives To determine the response process validity, feasibility of completion, acceptability and preferences for three patient-reported outcome measures that could be used in economic evaluation—the EQ-5D-5L, ICECAP-A and ICECAP-O—in people requiring kidney care.

Design Participants were asked to ‘think-aloud’ while completing the EQ-5D-5L, ICECAP-A and ICECAP-O, followed by a semistructured interview. Five raters identified errors or struggles in completing the measures from the think-aloud component of the transcripts. Patient preferences for measures were extracted from the semistructured interview.

Setting Eligible patients were identified through a large UK secondary care renal centre.

Participants In total, 30 participants were included in the study, consisting of patients attending renal outpatients for chronic kidney disease (n=18), with a functioning kidney transplant (n=6) and receiving haemodialysis (n=6).

Results Participants had few errors and struggles in completing the EQ-5D-5L (11% error rate, 3% struggle rate), ICECAP-A (2% error rate, 2% struggle rate) and ICECAP-O (4% error rate, 3% struggle rate). The main errors with the EQ-5D-5L were judgements that did not comply with the ‘your health today’ instruction. Comprehension errors were most prominent on ICECAP-O. Judgement errors were the only errors reported on ICECAP-A. Although the EQ-5D-5L had slightly more errors and struggles, it was the measure most preferred, with participants able to make a clearer link with EQ-5D-5L and their health condition.

Conclusions The EQ-5D-5L, ICECAP-A and ICECAP-O are feasible for people requiring kidney care to complete and can be included in studies conducting economic evaluations of kidney care interventions. Further research is required to assess how health (eg, EQ-5D) and capability (eg, ICECAP) measures can be included in an economic evaluation simultaneously, as well as what ICECAP measure(s) to include when patient groups straddle the age ranges for ICECAP-A (18 years and older) and ICECAP-O (65 years and older).

  • health economics
  • capability approach
  • qualitative research
  • quality of life
  • wellbeing
  • kidney care

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See:

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  • Contributors PM, FC and JC developed the study design. PM, FC and JS were involved in data acquisition. All authors were involved with analysing and interpreting the data. PM initially drafted this paper. All authors (PM, FC, JS, SS, JC) were involved in the revision of the initial draft for important intellectual content and final approval of this version to be published. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding This work was initially supported by a post-doctoral fellowship co-funded by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care West (NIHR CLAHRC West) and the UK Renal Registry (UKRR). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health and Social Care or the UKRR. Time for drafting this paper for Paul Mitchell and Joanna Coast has also been supported through a Wellcome Trust investigator award (205384/Z/16/Z).

  • Competing interests JC led the development of the ICECAP-O and ICECAP-A.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Patient consent for publication Not required.

  • Ethics approval Ethics approval was obtained from the East of England NHS Research Ethics Committee (16/EE/0331) (see supplementary file 1 for research protocol).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available.

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