The validity and responsiveness of the ICECAP-A capability-wellbeing measure in women with irritative lower urinary tract symptoms

Purpose: A desire to incorporate broader aspects of wellbeing in health economic evaluations has led to the development of the ICEpop CAPability measure for Adults (ICECAP-A). The ICECAP-A draws upon Amartya Sen’s capability approach, and conceptualises wellbeing as the capability to achieve Stability, Attachment, Autonomy, Achievement, and Enjoyment. The aim of this study is to assess the psychometric performance of the ICECAP-A in a context where patient outcomes can extend beyond health-related quality of life.

Methods: Longitudinal data were collected for 478 women with symptoms of urinary frequency and urgency, with or without incontinence. Women were recruited across 22 hospitals in the UK, and had a mean age of 55 (SD = 14). The psychometric performance of the measure was evaluated in relation to the EuroQol Five Dimension Questionnaire (EQ-5D-3L) and the International Consultation on Incontinence Questionnaire for Overactive Bladder (ICIQ-OAB), and involved an assessment of acceptability, construct validity, and responsiveness using parametric and non-parametric methods.

Results: ICECAP-A showed good convergence with the ICIQ-OAB with 20 out of 22 expected patterns of relationship confirmed. Findings suggested that the ICECAP-A has better discriminative properties than EQ-5D-3L and as good as those of the ICIQ-OAB, confirming expected associations with clinical and demographic factors. The ICECAP-A was more responsive than EQ-5D-3L and ICIQ-OAB to deteriorations of clinical symptoms. Improvements in symptoms were not valued as highly as deteriorations by either ICECAP-A or EQ-5D-3L.

Conclusions: The ICECAP-A is a valid and responsive measure capturing broad emotional and practical impacts of urinary symptoms on women’s wellbeing, and could be considered for use in economic evaluations in this context.