Pathophysiology of fecal incontinence in obese patients: A prospective case-matched study of 201 patients.

BACKGROUND: Obesity is an emerging risk factor for fecal incontinence (FI). The aim of this study was to characterize pathophysiologic mechanisms of FI in obese patients compared with non-obese patients in a prospective case-matched study. METHODS: The general characteristics and data of the anorectal manometry and endosonography of patients who were evaluated for FI at a single institution from 2005 to 2015 were prospectively assessed. Fecal incontinence was defined by a Cleveland Clinic Incontinence Score (CCIS) >4. Obesity was defined by a body mass index ≥30 kg/m2 . Obese patients were case-matched with two age- and sex-matched non-obese patients. KEY RESULTS: A total of 201 patients were included (67 obese matched with 134 non-obese). The CCIS, Knowles-Eccersley-Scott Symptom Constipation Score and quality of life score were comparable between obese and non-obese patients with FI. Factors significantly associated with obesity in FI patients were cholecystectomy (odds ratio [OR]=3.45 [1.19-10.32], P=.0230), irritable bowel syndrome - diarrhea (OR=2.94 [1.22-7.19], P=.0158), upper part of the anal canal resting pressure ≥22 mm Hg (OR=3.45 [1.45-8.76], P=.0045), maximum rectal tolerable volume ≥240 mL (OR=3.14 [1.34-7.54], P=.0082), and abdominal pressure ≥28 mm Hg (OR=2.75 [1.13-7.33], P=.0248) by multivariate analysis. CONCLUSIONS & INFERENCES: Obese patients with FI had a comparable severity of FI to that of non-obese patients with FI. Regarding obesity in patients with FI, physicians should focus on stool consistency.

Prospective cohort study of phenotypic variation based on an anal sphincter function in adults with fecal incontinence.

BACKGROUND: One-third of patients with fecal incontinence (FI) do not have any anal dysfunction. The aim was to characterize patients with FI with normal anal function compared with patients with anal weakness. METHODS: The general characteristics and data of anal manometry, endosonography, and defecography of patients who were evaluated for FI at a single institution from 2005 to 2015 were prospectively assessed. Fecal incontinence was defined by the Cleveland Clinic Incontinence Score (CCIS) >4. Anal weakness was defined by one or more of the three following parameters: <25 mmHg at the upper part of the anal canal, <26 mmHg at the lower part of the anal canal, and <60 mmHg for the mean squeeze pressure. KEY RESULTS: A total of 439 patients with FI were included (152 with normal anal function/287 with anal weakness). Severe constipation (Kess score ≥21) was predominant in patients with normal anal function (44/151 vs 50/284, respectively; p = 0.0054). Fecal incontinence with normal anal function was significantly associated with lower age (>63 years; odds ratio [OR] = 0.29), higher weight (>65 kg; OR = 1.69), fecal urgency (OR = 1.58), less severe FI score (CCIS score >10; OR = 0.52), higher abdominal pressure (>36 mmHg; OR = 2.15), and paradoxical puborectal contraction (OR = 2.07) in a multivariate analysis model. CONCLUSION & INFERENCES: Fecal incontinence with normal anal function is a specific phenotype that involves distal constipation and may be an early stage of FI with anal weakness. Physicians should adapt their management to focus on the treatment of constipation.