External Validation of SHAPE Score: A Score to Predict Low-Risk Lower Gastrointestinal Bleeding in the Emergency Department.

Lower gastrointestinal bleeding (LGIB) frequently leads to emergency department (ED) visits and hospitalizations, encompassing a spectrum of outcomes from spontaneous resolution to intrahospital mortality. The purpose of this study was to validate a scoring system designed to identify cases of low-risk LGIB, allowing for safe discharge from the ED. A retrospective analysis of all gastrointestinal bleeding cases presented at three EDs in 2020 was conducted, focusing specifically on patients with LGIB. The SHAPE score incorporates factors such as systolic blood pressure, hemoglobin levels, use of antiplatelet or anticoagulant medications, pulse rate, and episodes of bright blood per rectum. Out of 1112 patients presenting with LGIB to the ED, 55 were hospitalized, 20 required blood transfusions, 15 underwent colonoscopies, one underwent interventional radiology procedures, and two patients died. Employing a SHAPE score with a cutoff value of 1 yielded a specificity of 78.5% (95% CI (confidence interval) [75.8-81.0]), sensitivity of 76.8% (95% CI [63.6-87.0]), positive predictive value (PPV) of 17.0% (95% CI [12.6-22.2]), and negative predictive value (NPV) of 98.3% (95% CI [97.2-99.1]) for predicting the need for hospitalization and intrahospital intervention. When considering return visits to the ED within 7 days with the same presentation, the score demonstrated a specificity of 78.8% (95% CI [76.0-81.3]), sensitivity of 68.6% (95% CI [56.4-79.1]), PPV of 19% (95% CI [14.3-24.4]), and NPV of 97.2% (95% CI [95.8-98.2]). The SHAPE score demonstrates potential in predicting cases of low-risk LGIB, offering a high NPV for hospitalization, the need for intrahospital intervention, and return visits to the ED. However, these findings should be interpreted cautiously given the low prevalence of interventions and limitations in the study's population and design.