From the AGA Journals

Study documents obesity-related defecation disorders



A new study suggests that being obese is significantly associated with fecal incontinence, fecal urgency, and vaginal digitation, as well as clinically significant rectocele and increased anal resting and rectal pressures.

The study, which was published in the American Journal of Gastroenterology and led by Pam Chaichanavichkij, MBChB, MRCS, of Queen Mary University, London, included 1,155 patients (84% female, median age 52) who were obese (31.7%), overweight (34.8%), or of normal weight 33.5%).

“These results support the notion that rectal evacuation disorder/incomplete evacuation may be an important underlying mechanism for fecal incontinence in obese patients,” the authors wrote.

Obese patients had higher odds of fecal incontinence to liquid stools (69.9 vs. 47.8%; odds ratio, 1.96 [confidence interval, 1.43-2.70]), use of containment products (54.6% vs. 32.6%; OR, 1.81 [CI, 1.31-2.51]), fecal urgency (74.6% vs. 60.7%; OR, 1.54 [CI, 1.11-2.14]), urge fecal incontinence (63.4% vs. 47.3%, OR, 1.68 [CI, 1.23-2.29]), and vaginal digitation (18.0% vs. 9.7%; OR, 2.18 [CI, 1.26-3.86]).

Obese patients were also more likely to have functional constipation (50.3%), compared with overweight (44.8%) and normal weight patients (41.1%).

There was a positive linear association between body mass index (BMI) and anal resting pressure (beta 0.45; R2, 0.25, P = 0.0003), though the odds of anal hypertension were not significantly higher after Benjamini-Hochberg correction. Obese patients more often had a large clinically significant rectocele (34.4% vs. 20.6%; OR, 2.62 [CI, 1.51-4.55]), compared with normal BMI patients.

The data showed higher rates of gynecological surgery, cholecystectomy, diabetes, and self-reported use of opioids, antidepressants, and anticholinergic medications in the obese group, compared with the others.

In morphological differences measured by x-ray defecography, obese patients had more than two-fold higher odds of having a rectocele and even greater odds of the rectocele being large and clinically significant. Anal and rectal resting pressures were linearly related to increasing BMI, the authors report.

Because most patients in the study were female, the findings may not be generalizable to the general population or male patients. Also, diet and exercise, two factors that may affect defecation disorders, were not accounted for in this study.

Dr. Chaichanavichkij reported no disclosures. Two other authors reported financial relationships with Medtronic Inc. and MMS/Laborie.

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