Design and validation of a comprehensive fecal incontinence questionnaire.

PURPOSE: Fecal incontinence can have a profound effect on quality of life. Its prevalence remains uncertain because of stigma, lack of consistent definition, and dearth of validated measures. This study was designed to develop a valid clinical and epidemiologic questionnaire, building on current literature and expertise. METHODS: Patients and experts undertook face validity testing. Construct validity, criterion validity, and test-retest reliability was undertaken. Construct validity comprised factor analysis and internal consistency of the quality of life scale. The validity of known groups was tested against 77 control subjects by using regression models. Questionnaire results were compared with a stool diary for criterion validity. Test-retest reliability was calculated from repeated questionnaire completion. RESULTS: The questionnaire achieved good face validity. It was completed by 104 patients. The quality of life scale had four underlying traits (factor analysis) and high internal consistency (overall Cronbach alpha = 0.97). Patients and control subjects answered the questionnaire significantly differently (P < 0.01) in known-groups validity testing. Criterion validity assessment found mean differences close to zero. Median reliability for the whole questionnaire was 0.79 (range, 0.35-1). CONCLUSIONS: This questionnaire compares favorably with other available instruments, although the interpretation of stool consistency requires further research. Its sensitivity to treatment still needs to be investigated.

The prevalence of fecal incontinence in community-dwelling adults: a systematic review of the literature.

PURPOSE: Reported prevalence estimates for fecal incontinence among community-dwelling adults vary widely. A systematic review was undertaken to investigate the studied prevalence of fecal incontinence in the community and explore the heterogeneity of study designs and sources of bias that may explain variability in estimates. METHODS: A predetermined search strategy was used to locate all studies published that reported the prevalence of fecal incontinence in a community-based sample of adults. Data were extracted onto a proforma for sampling frame and method, sample size, response rate, definition of fecal incontinence used, data-collection method, and prevalence rates. Included studies were critically appraised for possible sources of selection bias, information bias, and imprecision. RESULTS: A total of 16 studies met the inclusion criteria. These could be grouped into definitions of incontinence that included or excluded incontinence of flatus. The estimated prevalence of anal incontinence (including flatus incontinence) varied from 2 to 24 percent, and the estimated prevalence of fecal incontinence (excluding flatus incontinence) varied from 0.4 to 18 percent. Only three studies were found to have a study design that minimized significant sources of bias, and only one of these used a validated instrument for data collection. The prevalence estimate of fecal incontinence from these studies was 11 to 15 percent. No pooling of estimates was undertaken because there was wide variation in study design. CONCLUSIONS: A consensus definition of fecal incontinence is needed that accounts for alterations in quality of life. Further cross-sectional studies are required that minimize bias in their design and use validated self-administered questionnaires.