Insights into the Neutrophil-to-Lymphocyte Ratio and the Platelet-to-Lymphocyte Ratio as Predictors for the Length of Stay and Readmission in Chronic Heart Failure Patients

Background/Objectives: Chronic heart failure (CHF) is characterized by complex pathophysiology, leading to increased hospitalizations and mortality. Inflammatory biomarkers such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) provide valuable diagnostic insights. Methods: This study evaluates the prognostic relationship between NLR, PLR, and, in a specific subcohort, N-terminal pro B-type natriuretic peptide (NT-proBNP), alongside length of stay (LOS) and 90-day readmission rates in CHF patients, irrespective of heart failure phenotype. A retrospective analysis of 427 CHF admissions (males = 57.84%) was conducted. Results: The mean age of the entire population was 68.48 ± 11.53 years. The average LOS was 8.33 ± 5.26 days, with a readmission rate of 73 visits (17.09%) for 56 patients. The NLR (3.79 ± 3.32) showed a low but positive correlation with the LOS (r = 0.222, p < 0.001). Conversely, the PLR (144.84 ± 83.08) did not demonstrate a significant association with the LOS. The NLR presented a low negative correlation for days until the next admission (r = −0.023, p = 0.048). In a prespecified subanalysis of 323 admissions, the NT-proBNP exhibited a low positive Pearson correlation with the NLR (r = 0.241, p < 0.001) and PLR (r = 0.151, p = 0.006). Conclusions: The impact of the NLR across heart failure phenotypes may suggest the role of systemic inflammation in understanding and managing CHF.