161 Optimizing Clinical Assessment and Diagnostic Evaluation in Patients With Chronic Constipation Based on Systematic Analysis of 97 Articles in the Literature

Abstract

INTRODUCTION: There is still controversy surrounding the use of symptoms, history, and tests for diagnosis of rectal evacuation disorders (RED) and slow transit constipation (STC). We performed a comprehensive literature-based analysis to ascertain pooled prevalence, sensitivity (SN), specificity (SP), and likelihood ratios (LR) for clinical parameters to determine pre- and post-test probabilities of diagnosing RED and STC without RED. METHODS: Using MEDLINE and PUBMED, we examined systematic and clinical reviews, meta-analyses, primers, guidelines, and consensus statements since 1999 to determine the diagnostic utility of history, symptoms, and testing for RED and STC. Studies were included if binary data were available to assess true/false positives or negatives to pool and calculate SN/SP/LR. Given there are no “gold standard” diagnostic criteria for RED or STC, designation of “true” RED or STC was based on confirmation by at least one objective anorectal or colonic transit test. Controls varied across studies; all had normal anorectal and/or transit tests by the specific protocol used in each study. We assessed STC alone (associated with normal anorectal testing). RESULTS: We reviewed 97 articles involving studies from many different countries, and 63 articles for RED and 61 articles for STC met inclusion/exclusion criteria. The prevalence of disease phenotypes among 4160 patients with chronic constipation based on objective testing was RED alone 23.3%, normal transit constipation (NTC) alone 31.9%, STC alone 16.2%, and RED + STC 14.3%. To diagnose RED (Figure 1, Table 1), the most clinically significant symptoms included hard/lumpy stools (+LR 269.6, n = 1583) and urinary symptoms (100% specificity, n = 58). The strongest digital rectal exam (DRE) findings were poor anal relaxation (+LR 5.3, n = 529) or increased anal squeeze (+LR 8.4, n = 395). The most predictive anorectal tests were balloon expulsion time >120 s (+LR 5.5, n = 551) and rectoanal pressure gradient < −40 mmHg with high anal pressure on straining on anorectal manometry (100% specificity, n = 101). For STC alone, the most predictive symptom was a call to stool (+LR 10.5, n = 75). Patients without abdominal distension/fullness/bloating were less likely to have RED (−LR 0.2, n = 324) or STC alone (−LR 0.2, n = 93). CONCLUSION: Symptom assessments and DREs are critical in the evaluation for RED and STC. RED is highly prevalent in patients presenting with chronic idiopathic constipation.