A comparison of faecal incontinence scoring systems

Questionnaires designed to score the severity of faecal incontinence (FI) are widely used to provide an evaluation of symptoms across settings, studies and time. The Pelvic Floor Disorders Consortium have recommended the use of multiple questionnaires despite some overlap of questions. This study aimed to evaluate whether patient responses to these questionnaires are consistent.

A retrospective analysis was undertaken of patients with FI who attended a dedicated pelvic floor unit between January 2018 and December 2019 and completed the Fecal Incontinence Severity Index, Cleveland Clinic Florida Incontinence Score and St Mark's Incontinence Score simultaneously. For each questionnaire the frequency of incontinence episodes to solid stool, liquid stool and gas was divided into five categories to allow direct comparison. Answers were deemed equivalent if the allocated response was identical, slightly different if the response was in an adjacent category or very different if the response differed to a greater extent.

There were 193 patients who simultaneously completed all three FI questionnaires. There were statistically significant differences between the responses regarding frequency of solid stool, liquid stool and gas incontinence on all three questionnaires (p < 0.005). Across all domains, between 58.0% and 69.9% of responses were equivalent, 14.1%-34.0% of answers were slightly different and 8.0%-18.8% were very different.

Even when completed at the same time, and by the same person, similar questions are answered differently a significant proportion of the time. The utility of using multiple questionnaires simultaneously in the clinical setting to assess FI symptoms should be questioned.