[Construction of a prediction model for predicting rebleeding in patients with obscure gastrointestinal bleeding after capsule endoscopy].

Objective: To explore the risk factors of rebleeding in patients with obscure gastrointestinal bleeding (OGIB) after capsule endoscopy (CE), and construct a model to predict rebleeding. Methods: The data of patients with OGIB who underwent CE in Zhongda Hospital Affiliated to Southeast University from July 2018 to September 2021 were retrospectively analyzed. Follow-up data were obtained via electronic medical records or telephone interviews. Univariate and multivariate Cox regression models were performed to figure out the risk factors of rebleeding in OGIB patients. Then the optimal prediction model was determined and presented as a nomogram. The model was evaluated by C statistic, calibration curve and decision curve analysis. Results: One hundred and thirty patients with OGIB were included, including 64 females and 66 males, aged (55.8±17.2) years (18-87 years), and 39 (30.0%) cases developed rebleeding during follow-up. Univariate and multivariate Cox regression model analysis showed the duration of more than 2 weeks OGIB (HR=3.70, 95%CI: 1.85-7.42, P<0.001), a history of previous gastrointestinal bleeding (HR=5.25, 95%CI: 2.00-13.81, P<0.001), positive CE findings (HR=3.72, 95%CI: 1.66-8.33, P=0.001), and the lowest hemoglobin level before CE<80 g/L (HR=2.00, 95%CI: 1.02-3.84, P=0.044) were risk factors for rebleeding, while specific treatment (HR=0.25, 95%CI: 0.11-0.54, P<0.001) was a protective factor. The corresponding scores of the above five predictive factors were: OGIB duration>2 weeks: 79 points; Previous history of gastrointestinal bleeding: 100 points; The result of CE was positive: 79 points; Specific treatment:-85 points; Minimum hemoglobin before CE<80 g/L: 41 points. The prediction model constructed from the above five variables had good discriminative capability (concordance index=0.798, 95%CI: 0.732-0.865). The calibration curves showed high consistency between nomogram-predicted probabilities and actual observations. The decision curves showed that when the threshold probability was above 0.04, the use of the nomogram to predict rebleeding provided a greater net benefit than the assumption of "all patients rebleeding or no patients rebleeding". Conclusion: The prediction model established in this study has a good ability to predic rebleeding in patients with OGIB after CE examination.目的： 分析影响不明原因消化道出血（OGIB）患者胶囊内镜（CE）检查后再出血的危险因素，构建再出血的预测模型。 方法： 回顾性收集2018年7月至2021年9月东南大学附属中大医院因OGIB行CE检查的患者的临床资料，通过查阅电子病历或进行电话随访。使用单因素和多因素Cox回归模型分析影响OGIB患者再出血的影响因素。确定最优预测模型，以列线图的形式展示。采用C统计量、校准曲线和决策曲线分析进行模型评价。 结果： 共纳入130例OGIB患者，女64例，男66例，年龄（55.8±17.2）岁（18~87岁），39例（30.0%）在随访期间发生再出血。单因素和多因素Cox回归模型分析提示OGIB病程>2周（HR=3.70，95%CI：1.85~7.42，P<0.001）、既往有消化道出血病史（HR=5.25，95%CI：2.00~13.81，P<0.001）、CE结果阳性（HR=3.72，95%CI：1.66~8.33，P=0.001）、CE前最低血红蛋白<80 g/L（HR=2.00，95%CI：1.02~3.84，P=0.044）是再出血的危险因素；而特异性治疗（HR=0.25，95%CI：0.11~0.54，P<0.001）是再出血的保护因素。以上5个预测因素的对应分值分别为：OGIB病程时间>2周：79分；既往消化道出血病史：100分；胶囊内镜结果阳性：79分；行特异性治疗：-85分；CE前最低血红蛋白<80 g/L：41分。由这5个变量构建的预测模型具有良好的区分度（C统计量=0.798，95%CI：0.732~0.865）。校准曲线显示，列线图的预测概率和实际观测概率间的一致性高。决策曲线显示，当阈值概率>0.04，使用列线图预测再出血比“所有患者均再出血或无患者再出血”的假设提供更大的净获益。 结论： 本研究构建的预测模型对OGIB患者CE检查后再出血具有良好的预测能力。.