Validation of British Society of Gastroenterology guidelines for acute lower GI bleeding from 8956 cases in Japan

Background and Aims: We sought to validate the British Society of Gastroenterology (BSG) guidelines for acute lower GI bleeding (ALGIB). Methods: We analyzed 8956 patients with ALGIB in the Colonic Diverticular Bleeding Leaders Update Evidence From Multicenter Japanese Study (CODE BLUE-J) study and categorized them into 4 groups based on the BSG guidelines. Outcomes included 30-day rebleeding, 30-day mortality, blood transfusion, therapeutic intervention, and severe bleeding. Results: The severe bleeding rates significantly decreased from group I to group IV: 92.1%, 70.1%, 58.7%, and 38.4%. The rate of the need for blood transfusion and 30-day mortality also decreased from group I to group IV. Although outpatient follow-up was recommended in group IV, it had high rates of severe bleeding (38%) and 30-day rebleeding (11%). Notably, for colonic diverticular bleeding, the rate of 30-day rebleeding was 25.5%, even with an Oakland score of ≤8. We identified abdominal pain, diarrhea, and a high white blood cell count as independent factors that differentiate between nonsevere and severe bleeding cases in group IV. Using these factors, we found that the 30-day rebleeding rate in the nonsevere group was 3.6%, suggesting the feasibility of outpatient follow-up in this group. Furthermore, a novel group, Group X, which deviated from the existing 4 groups, had a high severe bleeding rate (70.9%) comparable to that of group II. Conclusions: The BSG guidelines suggest a management approach that can clearly differentiate severity. However, caution is advised when using the Oakland score to triage patients for outpatient follow-up. Additionally, prompt intervention may be necessary for groups not covered by the guidelines.