Objective: To explore the diagnostic performance of blood urea nitrogen-to-creatinine (BUN/Cr) ratio in differentiating the site of gastrointestinal bleeding, and to assess the predictive value of early elevated BUN/Cr ratio for clinical outcomes in patients with acute nonvariceal upper gastrointestinal bleeding (ANVUGIB).
Methods: The adult patients diagnosed with gastrointestinal bleeding who were hospitalized in the Department of Gastroenterology, Zhongshan Hospital, Xiamen University between May 2020 and May 2021 were retrospectively enrolled. According to the site of gastrointestinal bleeding, the patients were divided into the upper gastrointestinal tract group, the proximal small intestinal bleeding group, and the distal small intestinal and colonic bleeding group. According to the early dynamic changes of BUN/Cr ratio within 6-48 hours after admission, patients with ANVUGIB were divided into early dynamic elevated BUN/Cr ratio group and non-early dynamic elevated BUN/Cr ratio group. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic performance of BUN/Cr ratio in differentiating the site of gastrointestinal bleeding and examine the predictive efficacy of early dynamic elevated BUN/Cr ratio after admission, Rockall scoring system, and the combined indicator of the two for estimating the primary clinical outcomes in ANVUGIB patients.
Results: A total of 266 patients were enrolled. Among them, 204 cases were in the upper gastrointestinal bleeding group, 15 cases were in the proximal small intestinal bleeding group, and 47 cases were in the distal small intestinal and colonic bleeding group. In the ANVUGIB patients, 16 were in the group with early dynamic elevated BUN/Cr ratio after admission, and 146 were in the group with non-early dynamic elevated BUN/Cr ratio after admission. The area under the ROC curve of the BUN/Cr ratio was 0.831 (95% CI: 0.780-0.874), the optimal cut-off value being 34.59 mg/g for differentiation between upper and lower gastrointestinal bleeding. The area under the ROC curve of the BUN/Cr ratio was 0.901 (95% CI: 0.798-0.963) and the optimal cut-off value was 19.27 mg/g for differentiation between proximal small intestinal bleeding and the distal small intestinal and colonic bleeding. The area under the ROC curve of the early dynamic elevated BUN/Cr ratio after admission was 0.806 (95% CI: 0.737-0.864) for predicting the primary clinical outcome in patients with ANVUGIB. The area under the ROC curve of the combined indicator included the early dynamic elevated BUN/Cr ratio after admission and the Rockall scoring system was 0.909 (95% CI: 0.854-0.949) for predicting the primary clinical outcome in patients with ANVUGIB.
Conclusion: The BUN/Cr ratio shows rather reliable diagnostic performance for identifying the site of gastrointestinal bleeding, and the early dynamic elevated BUN/Cr ratio after admission is a reliable indicator for predicting clinical outcomes in patients with ANVUGIB.
目的: 研究血尿素氮/肌酐（blood urea nitrogen-to-creatinine, BUN/Cr）比值在鉴别消化道出血部位中的诊断性能，以及BUN/Cr比值早期升高对于急性非静脉曲张性上消化道出血（acute nonvariceal upper gastrointestinal bleeding, ANVUGIB）患者临床结局事件的预测价值。
方法: 回顾性纳入2020年5月–2021年5月于厦门大学附属中山医院诊断为消化道出血的成年患者。根据不同消化道出血部位分为：上消化道出血组、小肠近段出血组、小肠远段及结肠出血组。根据ANVUGIB患者入院后早期（6～48 h内）BUN/Cr比值动态变化情况分为：入院后BUN/Cr比值早期动态升高组和入院后BUN/Cr比值非早期动态升高组。通过受试者操作特征（receiver operating characteristic, ROC）曲线分析BUN/Cr比值对于鉴别消化道出血部位的诊断性能，以及探究入院后BUN/Cr比值早期动态升高、Rockall评分系统及其两者联合指标对ANVUGIB患者主要临床结局事件（因为任何原因死亡；再次出现消化道出血；需要急诊外科手术干预；需要急诊介入手术干预）的预测效能。
结果: 共纳入266例消化道出血患者，其中上消化道出血组204例，小肠近段出血组15例，小肠远段及结肠出血组47例；ANVUGIB患者中，入院后BUN/Cr比值早期动态升高组16例，入院后BUN/Cr比值非早期动态升高组146例。BUN/Cr比值对鉴别上、下消化道出血的曲线下面积为0.831（95%CI：0.780～0.874），最佳截断值为34.59 mg/g；BUN/Cr比值对鉴别小肠近段出血、小肠远段及结肠出血的曲线下面积为0.901（95%CI：0.798～0.963），最佳截断值为19.27 mg/g。入院后BUN/Cr比值早期动态升高预测ANVUGIB患者主要临床结局事件的曲线下面积为0.806（95%CI：0.737～0.864），联合Rockall评分后的联合指标预测ANVUGIB患者主要临床结局事件的曲线下面积为0.909（95%CI：0.854～0.949）。
结论: BUN/Cr比值对于鉴别消化道出血部位具有较高的价值，且入院后BUN/Cr比值早期动态升高是预测ANVUGIB患者临床结局事件的可靠指标。
Keywords: Acute nonvariceal upper gastrointestinal bleeding; Blood urea nitrogen-to-creatinine ratio; Gastrointestinal bleeding; Predictive value; Small intestinal bleeding.
Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).