Predictive Value and Interexaminer Variability of Digital Rectal Examination for Dyssynergic Defecation in Constipated Patients Undergoing Anorectal Manometry

Abstract

Introduction: Determine the efficacy of digital rectal examination (DRE) to identify patients with dyssynergic defecation (DD) by anorectal manometry (ARM) and balloon expulsion test (BET). Methods: We performed a prospective cohort study in adults with chronic constipation (CC) referred for ARM and BET from 5/11 to 5/14. All patients (pts) met the Rome III criteria for functional constipation. Each pt underwent a DRE by an experienced gastroenterologist and ARM/BET by 1 skilled technician. Data from DRE and ARM were collected using a standardized form using prespecified normal and abnormal criteria. During DRE, examiners assessed for sphincter relaxation or paradoxical contraction during simulated defecation. DRE results were compared to ARM (sphincter relaxation or contraction during simulated defecation) and BET (abnormal defined as the inability to pass a 50 ml water filled rectal balloon in <60 seconds). Positive predictive values (PPV = TP/TP+FP), negative predictive values (NPV=TN/TN+FN) and 95% confidence intervals were calculated for the overall group and each GI provider. Results: 209 (188 [90%] females, 86% Caucasian, Mean age = 48, and Mean BMI = 27.4) adults with CC who underwent DRE and ARM/BET were included in the analysis. Overall, 33% of patients who underwent ARM had a paradoxical sphincter contraction and 67% had a normal sphincter relaxation during simulated defecation. 28.9% had an abnormal BET. Compared to ARM, DRE correctly identified paradoxical sphincter contraction during simulated defecation in 34% of patients. Using ARM as a gold standard, DRE accurately detected normal anal sphincter relaxation during simulated defecation in 67% of patients. Predictive values for DRE using BET as a gold standard were similar. (Table 1). When data was stratified by the 3 providers, no significant differences were found in their ability to detect paradoxical sphincter contraction or normal sphincter relaxation during simulated defecation.Table 1Conclusion: These results suggest that the greatest benefit of DRE is derived from a normal examination. Because clinicians had difficulty accurately identifying paradoxical sphincter contraction during simulated defecation, patients with an abnormal DRE should be referred for anorectal manometry to assess for dyssynergic defecation. These results were generalizable amongst multiple providers at our institution. Disclosure - William D. Chey - Consultant: Astra-Zeneca, Forest, Ironwood, Perrigo, Prometheus, Nestle, Sucampo, Takeda, Furiex, SK, Ferring, Entera, Research Grant: Ironwood, Prometheus, Nestle, Perrigo. Jason Baker - no conflicts to disclose. Stacy Menees - no conflicts to disclose. Shanti Eswaran - no conflicts to disclose. Monthira Maneerattanaporn - no conflicts to disclose. Richard Saad - no conflicts to disclose.