Characteristics, outcomes, and risk factors of surgery for acute lower gastrointestinal bleeding: nationwide cohort study of 10,342 hematochezia cases

Background Current evidence on the surgical rate, indication, procedure, risk factors, mortality, and postoperative rebleeding for acute lower gastrointestinal bleeding (ALGIB) is limited. Methods We constructed a retrospective cohort of 10,342 patients admitted for acute hematochezia at 49 hospitals (CODE BLUE J-Study) and evaluated clinical data on the surgeries performed. Results Surgery was performed in 1.3% (136/10342) of the cohort with high rates of colonoscopy (87.7%) and endoscopic hemostasis (26.7%). Indications for surgery included colonic diverticular bleeding (24%), colorectal cancer (22%), and small bowel bleeding (16%). Sixty-four percent of surgeries were for hemostasis for severe refractory bleeding. Postoperative rebleeding rates were 22% in patients with presumptive or obscure preoperative identification of the bleeding source and 12% in those with definitive identification. Thirty-day mortality rates were 1.5% and 0.8% in patients with and without surgery, respectively. Multivariate analysis showed that surgery-related risk factors were transfusion need ≥ 6 units ( P < 0.001), in-hospital rebleeding ( P < 0.001), small bowel bleeding ( P < 0.001), colorectal cancer ( P < 0.001), and hemorrhoids ( P < 0.001). Endoscopic hemostasis was negatively associated with surgery ( P = 0.003). For small bowel bleeding, the surgery rate was significantly lower in patients with endoscopic hemostasis as 2% compared to 12% without endoscopic hemostasis. Conclusions Our cohort study elucidated the outcomes and risks of the surgery. Extensive exploration including the small bowel to identify the source of bleeding and endoscopic hemostasis may reduce unnecessary surgery and improve the management of ALGIB.