The Agreement Between Digital Rectal Examination And High-Resolution AnorectalManometry In The Diagnosis Of Outlet Obstructive Constipation

Background&Objective:Functional Constipation (FC) has been a common problem that affects people’s quality of life. Constipation can be divided into three types according to pathophysiology, the slow-transit constipation, the outlet obstructive constipation and the mix type. The high-resqlution anorectal manometry (HARM) is mainly method to diagnose the outlet obstructive constipation, and the biofeedback therapy is an effective method to alleviate symptoms. But the anorectal manometry is not available in some undeveloped area, the diagnosis and treatment can be delayed. So a more convenient way to diagnose OOC is necessary. Digital rectal examination (DRE) can be a useful clinical tool, but its agreement with HARM has not been studied. We hypothesized that in patients presenting with constipation, a detailed DRE can identify those with outlet obstruction. The aim of our study was:1. Examine the agreement between DRE and HARM in the diagnosis of OOC.2. Compare difference of CSI scores between different types of FC patients. Methods:Consecutive patients referred to Qilu Hospital with symptoms of chronic constipation and difficult defecation, and who fulfilled the Rome III criteria for functional constipation were enrolled in this study. First they would fulfill Constipation Severity Instrument (CSI) to analysis the severity of symptoms. Then they underwent detailed DRE to diagnose whether they had OOC. Then they underwent High-resolution Anorectal Manometry (HRARM), which was the golden standard to diagnose OOC in this study. T-test was used to test whether there were any difference in CSI scores between OOC patients and non-OOC patients. The chi-square test was used to analysis the agreement between DRE and HRARM.Result:Of all the55patients enrolled in this study,32were diagnosed as OOC by HRARM, and23were diagnosed as non-OOC. The total CSI score is of no significant difference between two groups. But the two groups performed quite differently in the CSI subscale. The obstructive score is higher in OOC group (21.093±7.118VS.13.956±10.585, p<0.05), and the colonic inertia score is lower in OOC group (17.34±8.845VS.19.09±7.49,p<0.01).The mean resting anal pressure of OOC patients is higher than non-OOC patients (76.66±19.41vs.59.91±19.89mmHg, p<0.01). The squeezing pressure of OOC patients is higher than non-OOC patients (193.12±58.42vs1154.65±47.84mmHg, p<0.05). Among OOC patients, the proportion of patients with abnormal resting pressure is66%, with abnormal squeezing pressure is46%. In non-OOC patients, the proportion of patients with abnormal resting pressure is52%, with abnormal squeezing pressure is26%.In diagnosing abnormal resting pressure, the agreement of DRE and HARM is52.7%. In diagnosing abnormal squeezing pressure he agreement of DRE and HARM is70.9%.In diagnosing OOC, The specificity of DRE is0.844, specificity is0.913, PPV is0.931, NPV is0.808, consistency is0.873. Conclusion:OOC and non-OOC patients have very different CSI subscale scores, and the symptoms of OOC patients are typical. In OOC patients the proportion of patients with abnormal anorectal dynamic is higher than non-OOC patients. The agreement of DRE with HRARM in diagnosing OOC is good. DRE is a convenient and reliable way to detect OOC, and it has a promising use in the treatment of OOC.