Anorectal function evaluation and predictive factors for faecal incontinence in 600 patients

Abstract

Anorectal function was assessed in patients with and without faecal incontinence (FI) . Risk factors predictive for FI were determined. Between 2003 and 2009, all consecutive patients referred were assessed by questionnaire, anorectal manometry and anal endosonography. Predictive factors were identified and used to develop a statistical model to predict FI. Of 600 patients (519 women), 285 (48%) were faecally incontinent. In comparison with continent women, incontinent women (mean Vaizey score 15.4), were older, had more liquid stools, more deliveries, more urinary incontinence, lower anal pressures, shorter sphincter length, smaller rectal capacity and more sphincter defects. Incontinent men (mean Vaizey score 15.3) were older and had lower anal pressures. Incontinent and continent patients showed an overlap in test results. Predictors in women were age, stool consistency, anal pressures, rectal capacity, and internal and external sphincter defects. The area under the ROC-curve was 0.84 (P < 0.001; 95% confidence interval, 0.80-0.87). Using a cut off point of 0.4, FI was predicted with sensitivity, specificity, positive and negative predictive values of 86%, 68%, 74% and 82%, respectively. The model was studied in five women with a temporary stoma and was accurate in predicting FI after stoma closure. Incontinent patients have lower pressures, smaller rectal capacity and more sphincter defects than controls, but show a large overlap. Our model shows a relatively high sensitivity and negative predictive value for predicting FI in women. The model seems promising in the patients studied with a temporary stoma.