Work

Development, content validation and reliability assessment of the Bowel Irrigation Questionnaire, a Patient-Reported Experience Measure for Transanal Irrigation: a multi-methods study

Year: 2026

Type: preprint

Abstract: Objective To develop the Bowel Irrigation Questionnaire (BIQ), a patient-reported experience measure (PREM) designed to assess the users’ experience of transanal irrigation (TAI) and conduct preliminary evaluation of its content validity and temporal stability. Design A four-stage multi-methods study comprising: (1) item generation through literature review and qualitative interviews; (2) international three-round Delphi survey and consensus meeting; (3) content validity assessment through cognitive interviews and the Questionnaire on Questionnaires (QQ-10); (4) temporal stability assessment. Settings Item generation and the Delphi survey were conducted online with healthcare professionals (HCPs) and TAI users from the UK, Denmark, Sweden, Ireland and the Netherlands. Participants in content validity and temporal stability assessment were recruited from a UK site. Participants HCPs and TAI users were involved throughout development: (1) nine completed qualitative interviews (6 HCPs, 3 TAI users; 4 male, 5 female); (2) 20 completed the Delphi survey (12 HCPs, 8 TAI users; 7 male, 13 female) and (3) six TAI users completed cognitive interviews. Thirty-two TAI users (30 female, 93.8%; median age 52 years, IQR 34-54) completed the BIQ, followed by QQ-10 and repeated BIQ. Results Multi-disciplinary qualitative interviews and literature review generated 215 statements across 20 sub-domains, refined to 73 statements for Delphi survey. Following Delphi survey and cognitive interviews, the 16-item BIQ addressed training and support (one item); usability (five items), and user experience (10 items). Median QQ-10 value and burden scores were 21 (IQR 19-22.5) and 0 (IQR 0-2.3) respectively, supporting acceptability and face validity. Test-retest exact agreement ranged from 83.9% to 100% across items, with 100% agreement within one response category for every item. Conclusions The Bowel Irrigation Questionnaire is a PREM assessing the user experience of TAI. In preliminary assessment, the BIQ demonstrates good measurement properties; however, further psychometric evaluation is required before it can be recommended in clinical practice. Strengths and Limitations The item generation process was thorough and well-grounded in both literature review and qualitative interview, ensuring strong content validity from the outset. Transanal irrigation users were actively involved at every stage of development, supporting its relevance and use in real-world settings. Using an online Delphi survey meant we benefited from the input of topic experts from a range of countries whilst maintaining anonymity to minimise the influence of dominant individuals. This study represents the initial stages of PREM development; a larger study in a broader patient population is required to fully evaluate the psychometric properties of the instrument, including construct validity and internal consistency. No a priori content validity index thresholds or predefined criteria for removing sub-domains were specified; instead, decisions were made iteratively based on quantitative rating and qualitative feedback to balance content validity and patient burden. This may have influenced the final composition of the instrument.

Source: medRxiv

DOI: 10.64898/2026.07.16.26358225