Systematic review of the prevalence of faecal incontinence

Faecal incontinence (FI) is widely recognized as a significant problem in the community. Conjecture exists around the proportion of the population affected. This systematic review evaluated studies reporting the community prevalence of FI in terms of methodology, design and definitions.

MEDLINE, Embase, CINAHL, the Cochrane Collaboration and National Guideline databases were searched for studies investigating the prevalence of FI in community-based adults published from January 1966 to February 2015. Study data, including methodology, sample size, response rate, definition of FI and prevalence rates, were extracted on to a pro forma and appraised critically. Where possible, FI prevalence estimates were pooled.

Thirty studies were analysed from 4840 screened articles. FI prevalence estimates varied from 1·4 to 19·5 per cent. This variation was explained by differences in data collection method and two factors within definitions of FI: type of stool and frequency of FI episodes. When these factors were accounted for, the FI prevalence at a threshold of at least once per month for liquid or solid stool was 8·3-8·4 per cent for face-to-face or telephone interviews, and 11·2-12·4 per cent for postal surveys. The pooled prevalence rate from studies for functional FI (defined by ROME II criteria) was 5·9 (95 per cent c.i. 5·6 to 6·3) per cent.

When comparable methodologies and definitions are used, studies produce remarkably similar prevalence rates in different community populations. FI remains an unspoken symptom, with lower rates reported in personal interviews compared with anonymous postal questionnaires.