BackgroundThis study aimed to determine the performance of the Oakland, Glasgow‐Blatchford, and AIMS65 scores in predicting the clinical outcomes of acute lower gastrointestinal bleeding (LGIB).MethodsThis prospective cohort study was conducted from July 2020 to July 2021. Patients admitted with acute lower gastrointestinal bleeding were enrolled. The Oakland, Glasgow‐Blatchford, and AIMS65 scores were calculated. The primary outcome was validating the performance of the scores in predicting severe LGIB; secondary outcomes were comparing the performance of the scores in predicting the need for blood transfusion, hemostatic interventions, in‐hospital rebleeding, and mortality. Receiver operating characteristic curves were calculated for all outcomes. The associations between all three scores and the primary outcomes were calculated using multivariate logistic regression analysis.ResultsPatients with acute LGIB (n = 150) were enrolled (88 [58.7%] men and mean age: 63.6 ± 17.3 years). The rates of severe LGIB, need for blood transfusion, hemostatic intervention, in‐hospital rebleeding, and in‐hospital mortality were 54.7%, 79.3%, 10.7%, and 3.3%, respectively. The Oakland and Glasgow‐Blatchford scores had comparable performance in predicting severe LGIB, need for blood transfusion, and mortality, outperforming the AIMS65 score. All scores were suboptimal for predicting hemostatic interventions and rebleeding.ConclusionsOur results demonstrate the predictive performances of the Oakland score and the GBS are excellent and comparable for severe LGIB, the need for blood transfusion, and in‐hospital mortality in patients with acute LGIB. Thus, GBS could be considered as an alternative predictive score for stratification of the patients with acute LGIB.