Responsiveness and interpretability of incontinence severity scores and FIQL in patients with fecal incontinence: a secondary analysis from a randomized controlled trial.

INTRODUCTION AND HYPOTHESIS: This study aims to assess the responsiveness and interpretability of the Vaizey score, Wexner score, and the Fecal Incontinence Quality of Life Scale (FIQL) for use in the evaluation of patients with fecal incontinence (FI). METHODS: Eighty patients with FI with a mean age of 59.3 (SD +/- 11.9) were enrolled in a randomized controlled trial. The patient-reported outcomes were tested for internal and external responsiveness, longitudinal construct validity, and interpretability. RESULTS: All total scores proved to have both adequate to excellent responsiveness and longitudinal construct validity, and changes were in agreement with subjective improvement. Due to variability in minimally important change estimates (Vaizey score -5 to -3, Wexner score -3 to -2, FIQL 1.1 to 1.2), they should be used as indicators. All patient-reported outcomes showed psychometric or practical limitations. CONCLUSIONS: The instruments available to date to evaluate severity and quality of life in FI do not yet attain the highest levels of psychometric soundness. As the focus of patients may differ from that of physicians, it is recommended that several measures should be included for evaluation. So far, there are suggestions that the Wexner score is most suitable for severity assessment and the FIQL for evaluating quality of life.