A Predictive Model for Differential Diagnosis of Cardiogenic and Non‐cardiogenic Dyspnea in Patients with Chronic Kidney Disease Based on Cardio and Lung Ultrasound Features: A Single‐Center Observational Study

OBJECTIVES: Lung ultrasound (LUS) quantifying B-lines is valuable to assess fluid status during hemodialysis. However, B-lines may indicate not only cardiogenic pulmonary edema (CPE) but also non-cardiogenic pulmonary diseases, such as pneumonia or interstitial lung disease, posing challenges to guiding fluid therapy decisions. We developed a combined cardiac-LUS diagnostic model to differentiate these etiologies, aiming to prevent misdiagnosis and optimize treatment. METHODS: This retrospective observational study enrolled chronic kidney disease (CKD) stage 3-5 patients divided into training and validation cohorts. Participants were classified into CPE group or non-cardiogenic dyspnea (NCD) group. Multivariable logistic regression identified discriminative echocardiographic and LUS parameters to build a diagnostic model. Predictive performance was assessed using receiver operator characteristic (ROC), calibration and decision curve analysis. A simplified β-weighted scoring system was developed and evaluated. RESULTS: This retrospective study analyzed 215 training and 56 validation participants. Multivariable regression identified E/e' (OR 1.180, 95% CI 1.067-1.304, p = .001), inferior vena cava diameter (OR 1.240, 95% CI 1.023-1.503, p = .029), bilateral symmetric B-pattern (OR 9.720, 95% CI 2.707-34.899, p < .001), bilateral continuous B-pattern (OR 13.777, 95% CI 3.666-51.770, p < .001), ≥1 irregular pleural line region (OR 0.078, 95% CI 0.018-0.326, p < .001), ≥1 consolidation region (OR 0.039, 95% CI 0.008-0.196, p < .001), ≥1 pleural effusion region (OR 4.732, 95% CI 1.148-19.510, p = .032) as independent CPE predictors. The nomogram showed good discrimination, with area under the curve (AUC) of 0.9703 (training) and 0.8910 (validation). The β-weighted scoring system (cut-off as 42.99 scores) showed an AUC of 0.968 (training) and 0.888 (validation). CONCLUSION: The nomogram model demonstrated that the ultrasound parameters and β-weighted scoring system possess reliable clinical application value and high predictive accuracy.