Measuring health-related quality of life and well-being in adults with fecal incontinence: a comparative psychometric evaluation

Background While traditional disease-management regarding fecal incontinence (FI) primarily focuses on symptom-control and health-related quality of life (HrQoL) outcomes, patients often prioritize broader aspects of health, like well-being. This study evaluates the psychometric performance of ICEpop CAPability measure for Adults (ICECAP-A), a capability-based well-being instrument, alongside two established HrQoL-instruments, EQ-5D-5L and the FI quality of life (FIQL) questionnaire, in an outpatient-population with FI. Methods Data were obtained from patients with FI recruited from a randomized-controlled trial evaluating the efficacy of anal plugs for FI ((The CONFIDEnCE trial, NCT04657588). Psychometric evaluation of ICECAP-A involved the assessment of the convergent validity, known-group validity (examined across predefined subgroups), acceptability, and floor and ceiling effects. Results Among 72 participants (mean age 67.3years; 83.3% female), the mean ICECAP-A capability score (0.86, scale 0-1) exceeded the mean EQ-5D-5L utility (0.71, scale - 0.446-1) and the FIQL score (2.34, scale 1-5). ICECAP-A showed good convergent validity (76.6% predefined hypotheses confirmed). Known-group validity was comparable across instruments; ICECAP-A demonstrating significant differences by EQ-VAS, anxiety, and education level, but not outperforming EQ-5D-5L or FIQL. EQ-5D-5L showed stronger effect sizes for anxiety (p < 0.001), depression and symptom severity (non-significant), while FIQL was stronger for education level (p = 0.002). Questionnaire completion was 84.7% overall, reflecting trial dropout only (100% among completers) with no substantial floor or ceiling effects. Conclusions In patients with FI, ICECAP-A showed psychometric performance comparable to EQ-5D-5L and FIQL, despite its broader conceptual scope. Well-being appeared less influenced by symptom severity, possibly reflecting coping or adaptation. Further research is warranted evaluating ICECAP-A's psychometric advantage over traditional HrQoL-instruments in this clinical context.