Association Between the Naples Prognostic Score and In-Hospital Mortality in Patients with Type 2 Cardiorenal Syndrome: A Retrospective Cohort Study

Objective: This study evaluated the association between admission Naples Prognostic Score (NPS) and in-hospital mortality in patients with clinical features consistent with type 2 cardiorenal syndrome (CRS-2). Methods: This retrospective, single-center study included 101 adults hospitalized for decompensated heart failure at Sakarya University Training and Research Hospital between June 2021 and August 2024. CRS-2 classification relied on nephrologist review of historical records. Admission NPS combined albumin, total cholesterol, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio. NPS was analyzed primarily as a continuous score using univariable and multivariable Firth penalized logistic regression with profile penalized-likelihood confidence intervals. Low (0–2) versus high (3–4) NPS comparisons were exploratory; no patient scored 0. Results: Overall, 26 patients (25.7%) died. Mortality was higher in the high-NPS than the low-NPS group (24/52 [46.2%] versus 2/49 [4.1%]; p < 0.001). After adjustment for age, New York Heart Association (NYHA) functional class, and left ventricular ejection fraction (LVEF), the odds ratio per one-point NPS increase was 3.42 (95% confidence interval [CI], 1.76–7.77; p < 0.001). The area under the receiver operating characteristic curve was 0.825 (percentile bootstrap 95% CI, 0.744–0.896). At the established NPS ≥ 3 category boundary, sensitivity was 92.3% (95% CI, 75.9–97.9%) and specificity was 62.7% (95% CI, 51.4–72.7%). Performance was estimated within the same cohort without optimism correction or external validation. Conclusions: Higher admission NPS was associated with in-hospital mortality after adjustment for age, NYHA class, and LVEF. These exploratory findings require external validation and assessment of incremental predictive value and clinical utility.