Three subtypes of fecal incontinence (FI) are described in the literature: urge, mixed and passive FI, but the relevance of this classification remains unknown. To our knowledge, no questionnaire has been validated in a general population of patients with FI to classify patients between the different subtypes of FI. The aim of the present study was to validate the Fecal Incontinence Subtype Assessment (FI-SA) questionnaire in a general population of patients with FI.

All consecutive patients referred to our unit for physiological investigations of anorectal function in case of FI were included. A feasibility study was done to assess the acceptability, understanding, and the reproducibility of the FI-SA questionnaire. Its performance to correctly classify patients between subtypes of FI was evaluated in both a feasibility study and in a validation study, using clinical interview as gold standard.

The FI-SA questionnaire was found to be well accepted and easily understood by patients. Moreover, it was filled rapidly by patients, with a good reproducibility with an intra-class correlation coefficient of 0.97 and 0.87 for questions 1 and 2. Lastly, the accuracy of the FI-SA questionnaire to predict subtypes of FI was 93.3 % in the feasibility study (n = 30) and 81.1 % in the validation study (n = 100), in comparison with clinical interview as gold standard.

The FI-SA questionnaire could be used in the future to help standardize the methodology used among studies to evaluate the classification of patients in different subtypes of FI and ultimately to guide therapeutics.