Distinct clinical course and poor outcomes of small bowel bleeding in acute hematochezia: a nationwide multicenter study

Although small bowel bleeding is a known cause of acute lower gastrointestinal bleeding (ALGIB), its outcomes compared to colorectal bleeding remain underexplored. This study aimed to identify baseline characteristics and short- and long-term outcomes associated with small bowel bleeding in comparison to colorectal bleeding. This nationwide retrospective cohort study, based on CODE BLUE-J study, involved 10,342 patients hospitalized for ALGIB. Among 195 patients (2.8%) with acute small bowel bleeding, significant associations were observed with laboratory parameters (e.g., low hemoglobin, platelets, and albumin), clinical signs (e.g., tarry stool), and medical history, compared to 6832 patients with colorectal bleeding. Multivariate regression analysis showed no significant difference in 30-day rebleeding or mortality between small bowel and colorectal bleeding. However, small bowel bleeding was associated with higher transfusion volume, lower endoscopic treatment rate, higher rates of interventional radiology and surgery, and longer hospital stay (all p < 0.005). While long-term cumulative rebleeding rates were similar, cumulative mortality was significantly higher in the small bowel bleeding group (p < 0.001). This large-scale endoscopic study revealed differences in several clinical factors at presentation and in short- and long-term outcomes between small bowel and colorectal bleeding. These findings underscore importance of identifying small bowel bleeding in ALGIB.