Quality of life in coeliac disease: qualitative interviews to develop candidate items for the Coeliac Disease Assessment Questionnaire

BACKGROUND: Coeliac-specific measures have been criticized for not complying with current guidance on the development of patient-reported outcome measures (PROMs). The aim of this study was to develop a measure to assess health-related quality of life in adults with coeliac disease (CD), in accordance with current guidance for PROM development. METHODS: In-depth qualitative interviews were conducted with adults with CD. A thematic analysis was undertaken to develop a coding framework. All interviews were analyzed according to this framework. Interviewing continued until data saturation was achieved. Candidate items were developed on the basis of the interview findings. RESULTS: The analysis revealed 6 themes: 1) symptoms, 2) gluten-free diet, 3) emotional health, 4) impact on activities, 5) relationships, and 6) financial issues. Data saturation was reached after 8 interviews, but a total of 23 interviews were conducted to include a wide enough range of diverse participants. From the themes, 64 candidate items (9 for symptoms, 15 for emotional health, 16 for gluten-free diet, 7 for relationships, 12 for impact on activities, and 5 for financial issues) were developed to form the first draft of the Coeliac Disease Assessment Questionnaire (CDAQ). CONCLUSION: The 64 items reflect all the issues of importance to people with CD. Next, these items will be pretested and refined to lead to a shorter draft version of the CDAQ before it is administered in a survey to produce a final version with subscales.