In-hospital mortality in patients with lower gastrointestinal bleeding: development and validation of a prediction score

Background Lower gastrointestinal bleeding (LGIB) is a common condition linked to increased morbidity, healthcare costs, and mortality. Currently, no prospectively validated prognostic model exists to predict mortality in patients with LGIB. Our aim was to develop and validate a risk score that could accurately predict in-hospital mortality of patients admitted for LGIB. Methods Patient data from a nationwide cohort study in 15 centers in Italy (2019–2020) were used to derive the risk score, the Acute Lower gastrointestinal Bleeding and In-hospital mortality (ALIBI) score; the model was then externally validated in a cohort of consecutive patients hospitalized for LGIB in 12 centers from six countries (Italy, Spain, France, Greece, Iran, and Brazil) from 2022 to 2024. The main outcome was in-hospital mortality; we also reported rebleeding rates and the in-hospital mortality rate stratified by risk score and timing of colonoscopy. Results Among 1198 patients in the derivation cohort, 105 (8.8%) re-bled and 41 (3.4%) died. Age, Charlson Co-morbidity Index, in-hospital onset, hemodynamic instability, and creatinine level were independent predictors of in-hospital mortality. The model demonstrated excellent discrimination (area under the receiver operating curve [AUROC] 0.81, 95%CI 0.75–0.87) and calibration. In the validation cohort (n = 752 patients), the model's good discrimination (AUROC 0.79, 95%CI 0.72–0.86) and calibration were confirmed. Patients were categorized as low (0–4 points; 1% mortality), intermediate (5–9 points; 4.6% mortality), or high risk (10–13 points; 19.1% mortality). Conclusion A new validated score effectively predicts in-hospital mortality in patients with LGIB, aiding in their risk stratification and management.