Prevalence of anal incontinence according to age and gender: a systematic review and meta-regression analysis

Context: Anal incontinence is increasingly being recognised as a significant cause of physical and psychological morbidity with implications for healthcare provision within the community. There is controversy about which population groups are most disadvantaged by this chronic condition. Objectives: The aim of this study was to evaluate the prevalence of this condition in the community according to age and gender, a systematic review was performed. Data sources: Data were from Embase, Medline, bibliographies of known articles and contact with experts. Study selection: Studies were selected if data on anal incontinence could be extracted for participants over 15 years of age and living in the community. Data extraction: Data were extracted using a piloted form on participants' characteristics, study quality and incontinence rates. Data synthesis: Meta-analysis was used to combine data from multiple studies, and meta-regression evaluated the variation in rates according to age and gender in an analysis adjusted for study quality. Results: There were 29 studies (69,152 participants), of which 5 met over half of the high quality criteria. The rate of solid and liquid faecal incontinence among people aged 15-60 years was 0.8% [95% confidence interval (CI) 0.3-1.9] in men and 1.6% (95% CI 0.8-3.1) in women. In those aged over 60, this increased to 5.1% (95% CI 3.4-7.6) in men and 6.2% (95% CI 4.9-8.0) in women. Meta-regression showed that age had a significant influence on rates of solid and liquid faecal incontinence (p=0.007), but not gender (p=0.368) or study quality (p=0.085). Conclusions: The rate of solid and liquid faecal incontinence in older people is significantly higher than their younger counterparts. Gender differences in rates did not reach statistical significance.