Admission NT-proBNP-to-Albumin Ratio, Systemic Immune-Inflammation Index, and Early Severe Clinical Deterioration in Acute Decompensated Heart Failure

Abstract Background Early risk stratification in acute decompensated heart failure (ADHF) remains challenging in the emergency department. This study aimed to evaluate the association between admission-based laboratory biomarkers, composite inflammatory indices, and early severe clinical deterioration in patients hospitalized with ADHF. Methods This retrospective single-center cohort study included 1,450 adult patients hospitalized from the emergency department with ADHF between January 2023 and January 2025. Admission laboratory biomarkers and composite indices, including the systemic immune-inflammation index (SII), C-reactive protein-to-albumin ratio (CAR), prognostic nutritional index (PNI), and log10 NT-proBNP-to-albumin ratio, were evaluated. The primary outcome was a composite severe clinical course defined as intensive care unit admission, non-invasive ventilation (NIV), or endotracheal intubation during index hospitalization. Results Severe clinical course occurred in 338 patients (23.3%). In multivariable analysis, the log10 NT-proBNP-to-albumin ratio remained independently associated with severe clinical course in both tested models (Model 1: OR 2.008, 95% CI 1.493–2.701; Model 2: OR 1.988, 95% CI 1.498–2.640; both p < 0.001). In the extended model, SII was also independently associated with severe clinical course (OR 1.179 per doubling, 95% CI 1.075–1.293, p < 0.001). ROC curve analysis demonstrated statistically significant but limited discriminatory performance for both the log10 NT-proBNP-to-albumin ratio (AUC 0.608, 95% CI 0.570–0.646, p < 0.001) and SII (AUC 0.595, 95% CI 0.559–0.631, p < 0.001). Conclusion In patients hospitalized with ADHF, early severe clinical deterioration was associated with higher inflammatory, cardiorenal, and myocardial stress markers. The log10 NT-proBNP-to-albumin ratio showed the most consistent independent association, while SII provided an additional inflammatory risk signal. These routinely available admission-based indices may provide complementary information for early risk assessment but demonstrated only modest discriminatory performance.