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

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.