ABSTRACT
BACKGROUND: The differences in clinical outcomes following emergency medical services between high and low-volume centers with respect to acute lower gastrointestinal bleeding (ALGIB) remain unknown. In this study, we aimed to compare clinical outcomes and management strategies between high and low-volume centers in emergency medical services. METHODS: In this retrospective study, propensity score matching was used to compare high and low-volume hospitals with respect to emergency medical services. We identified 10,550 cases of ALGIB from 43 hospitals including one prefectural group between May 2002 and August 2020. After excluding duplicated cases, 8,286 cases were included and divided into two groups (high and low-volume centers) according to the number of emergency medical services performed in 2019. Hospitals with more than 5,000 cases of emergency medical services in 2019 were categorized as high-volume centers. The remaining centers were considered to be low-volume centers. Age;sex;history of colectomy and colonic diverticular bleeding (CDB);and comorbidities, including Charlson Comorbidity Index, vital signs at admission, laboratory data, and use of antithrombotic agents were used to calculate propensity scores that were matched one-to-one using the nearest neighbor method and applied to the high and the low-volume centers. We compared the two groups in terms of the diagnostic and treatment strategies used, which included computed tomography (CT) and colonoscopy, as well as the clinical outcomes thereof. RESULTS: A total of 2,652 patients were matched in each group. Although CDB was the most common cause of ALGIB in both groups, the proportions of definitive and presumptive CDB were both significantly higher in the low-volume centers (22% vs. 16%, P < 0.0001;45% vs. 41%, P=0.001). Both CT and enhanced CT were performed with greater frequency in the high-volume centers (80% vs. 66%, P < 0.0001;77% vs. 67%, P < 0.0001), but colonoscopy was not (84% vs. 94%, P < 0.0001). The proportion of patients who underwent either early colonoscopy (performed within 24 hours after admission) or endoscopic therapy was significantly lower in the high-volume centers (56% vs. 72%, P <0.0001;24% vs. 30%, P < 0.0001). The incidence of early rebleeding was not significantly different between the groups (16% vs. 18%, P=0.097). The median values (interquartile range) of PRBCs transfused were highest in the high-volume centers (0 [4] vs. 0 [2], P < 0.0001). However, a significant difference was not observed in LOS (7 [7] vs. 7 [6], P=0.069). CONCLUSION: Although clinical strategies for the management of ALGIB varied between the hospitals with high or low volumes of emergency medical services, early rebleeding did not differ between the two groups.