Systematic review and meta‐analysis of anal motor and rectal sensory dysfunction in male and female patients undergoing anorectal manometry for symptoms of faecal incontinence

AIM: Manometry is the best established technique to assess anorectal function in faecal incontinence. By systematic review, pooled prevalences of anal hypotonia/hypocontractility and rectal hypersensitivity/hyposensitivity in male and female patients were determined in controlled studies using anorectal manometry. METHODS: Searches of MEDLINE and Embase were completed. Screening, data extraction and bias assessment were performed by two reviewers. Meta‐analysis was performed based on a random effects model with heterogeneity evaluated by I (2). RESULTS: Of 2116 identified records, only 13 studies (2981 faecal incontinence patients; 1028 controls) met the inclusion criteria. Anal tone was evaluated in 10 studies and contractility in 11; rectal sensitivity in five. Only three studies had low risk of bias. Pooled prevalence of anal hypotonia was 44% (95% CI 32–56, I (2) = 96.35%) in women and 27% (95% CI 14–40, I (2) = 94.12%) in men. The pooled prevalence of anal hypocontractility was 69% (95% CI 57–81; I (2) = 98.17%) in women and 36% (95% CI 18–53; I (2) = 96.77%) in men. Pooled prevalence of rectal hypersensitivity was 10% (95% CI 4–15; I (2) = 80.09%) in women and 4% (95% CI 1–7; I (2) = 51.25%) in men, whereas hyposensitivity had a pooled prevalence of 7% (95% CI 5–9; I(2) = 0.00%) in women compared to 19% (95% CI 15–23; I (2) = 0.00%) in men. CONCLUSIONS: The number of appropriately controlled studies of anorectal manometry is small with fewer still at low risk of bias. Results were subject to gender differences, wide confidence intervals and high heterogeneity indicating the need for international collective effort to harmonize practice and reporting to improve certainty of diagnosis.