Are There Sex Differences in Defecation Patterns in Patients with Defecation Disorders?-A Single-center Observational Study

Objectives: Defecation disorders (DD) are characterized by impaired rectal evacuation due to inadequate defecatory propulsion and/or dyssynergic defecation. DD are assessed by rectal and anal pressures during attempted defecation using anorectal manometry (ARM). Thus far, at least four types of dyssynergic patterns have been recognized on ARM. This study aimed to compare the manometric parameters and dyssynergic patterns between men and women with DD. Methods: This study enrolled consecutive patients undergoing anorectal tests for symptoms of DD. Anorectal pressure was measured using a waveform ARM system. DD were diagnosed based on the results of ARM, balloon expulsion tests, and barium defecography. Dyssynergic patterns were defined as a paradoxical increase in anal pressure with (type I) or without (type II) an adequate increase in rectal pressure and failure of a reduction in anal pressure with (type III) or without (type IV) an adequate increase in rectal pressure. Results: This study evaluated 324 women and 234 men. Based on anorectal tests, 73.1% men and 54.6% women were diagnosed with DD. Rectal and anal pressures during attempted defecation in patients with DD were significantly higher in men than in women. Type I patterns were more common in men (64.9%) than in women (28.2%). Conversely, type II (42.9% vs. 24.0%) and IV (20.9% vs. 5.8%) patterns were observed more frequently in women than in men. Conclusions: Men were more likely to experience dyssynergic defecation whereas women were more likely to experience inadequate defecatory propulsion. However, future studies are warranted to confirm these results.