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. Obese patients with fecal incontinence (FI) had a comparable severity of FI and quality of life to those of non‐obese patients with FI. Stool consistency is the main factor associated with obesity in FI.