The clinical impact of obesity in patients with disorders of defecation: a cross-sectional study of 1,155 patients.

ObjectivesObesity is a global epidemic. Its clinical impact on symptoms of fecal incontinence (FI) and/or constipation and underlying anorectal pathophysiology remains uncertain.MethodsCross-sectional study of consecutive patients meeting Rome IV criteria for FI and/or functional constipation, with data on body mass index (BMI), attending a tertiary center for investigation between 2017-2021. Clinical history, symptoms and anorectal physiologic test results were analyzed according to BMI categories.Results1,155 patients (84% female) were included in the analysis (33.5% normal BMI; 34.8% overweight; 31.7% obese). Obese patients had higher odds of FI to liquid stools (69.9 vs. 47.8%, OR 1.96 [CI: 1.43-2.70]), use of containment products (54.6% vs. 32.6%, OR 1.81 [1.31-2.51]), fecal urgency (74.6% vs. 60.7%, OR 1.54 [1.11-2.14]) urge FI (63.4% vs 47.3%, OR 1.68 [1.23-2.29]), and vaginal digitation (18.0% vs 9.7%, OR 2.18 [1.26-3.86]). Higher proportions of obese patients had Rome criteria-based FI or coexistent FI and functional constipation (37.3%, 50.3%) compared with overweight (33.8%, 44.8%) and normal BMI patients (28.9%, 41.1%). There was a positive linear association between BMI and anal resting pressure (β 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 [1.51-4.55]) compared with normal BMI patients.ConclusionObesity impacts specific defecatory (mainly FI) and prolapse symptoms and pathophysiologic findings (higher anal resting pressure, significant rectocele). Prospective studies are required to determine if obesity is a modifiable risk factor for FI and constipation.