Prevalence and Predictors of Functional Evacuation Disorder in Patients with Chronic Constipation

Background Functional evacuation disorder (FED) is the second most common cause of functional constipation (FC) after constipation-predominant irritable bowel syndrome. However, the data on FED is relatively scanty in our region. Hence, the present study was performed to evaluate the demographics of FED and to find out the predictors of FED in patients with chronic constipation. Methods A total of 134 patients with chronic constipation diagnosed according to the Rome IV criteria who were referred for high-resolution anorectal manometry (HRAM) were retrospectively enrolled in the present study. All FC patients who underwent HRAM were asked to fill a questionnaire and underwent anorectal manometry and were submitted to the balloon expulsion test (BET). Results The mean age of patients was 43.09 ± 9.32 years old, with a total of 76 (54%) males. The most common symptom was straining during defecation (87%) followed by incomplete evacuation (86%). The prevalence of FED, diagnosed by HRAM and by the BET was 39%. Patients with FED had a significantly higher percentage of straining and sensation of anorectal blockade compared with those without FED (96 versus 82%; p < 0.01; 81 versus 44%; p < 0.001, respectively). On the multivariate regression analysis, straining > 30 minutes (odds ratio [OR] = 3.63; p = 0.03), maximum squeeze pressure (OR = 1.05; p < 0.001), and balloon volume at maximal sensation (OR = 1.06; p < 0.001) were found to be significant independent predictors of FED. Conclusion Prolonged straining and sensation of anorectal blockade were significant indicators of FED in patients with chronic constipation.