Diagnostic yield of colonoscopy to evaluate melena after a nondiagnostic EGD

Background: Melena can be caused by bleeding from lower GI sources. Colonoscopy is frequently used to investigate melena after a nondiagnostic EGD. Objective: To determine the diagnostic yield and rate of therapeutic intervention during colonoscopy in patients with melena and a nondiagnostic EGD. Design: Retrospective case-control study. Setting: Community and academic centers over a diverse geographic area in the United States. Patients: This study involved patients in the Clinical Outcomes Research Initiative database with a colonoscopy performed to investigate melena within 30 days of a nondiagnostic EGD for the same indication. A control group had colonoscopies performed for average-risk screening. Main Outcome Measurements: The endoscopic finding of a suspected bleeding source defined as right-sided arteriovenous malformation, colitis, polyp ≥ 20 mm, tumor, or ulcer. Rate of therapeutic intervention during colonoscopy. Results: Colonoscopy found a suspected bleeding source in 4.8% of patients with melena, more frequently than in the control group (odds ratio [OR] 2.17; 95% confidence interval [CI], 1.65-2.86; P <.0001). The rate of therapeutic intervention during melena-related colonoscopy was 1.7%. Patients with melena were more likely to have a colon tumor (OR 2.87; 95% CI, 1.82-5.51; P <.0001) than were control patients. Limitations: Retrospective design, conclusions being dependent on the accuracy of database input, and lack of pertinent clinical data (eg, hemoglobin). Conclusion: The diagnostic yield of colonoscopy to investigate melena after nondiagnostic EGD is low. The need for therapeutic intervention during colonoscopy for this indication is very low. This population should undergo colonoscopy because they are at increased risk of colorectal cancer. Colonoscopy can potentially be performed electively in stable patients without continued bleeding.