Background and Objectives: Heart failure is a chronic disease with a high risk of mortality and morbidity. In these patients, inflammatory markers have been shown to be associated with cardiovascular adverse outcomes and disease progression. To investigate the relationships between eosinophil indices and major cardiovascular events (MACE) in patients with acute decompensated heart failure (ADHF) with reduced ejection fraction. Materials and Methods: A total of 395 consecutive patients admitted to the intensive care unit (ICU) with ADHF and reduced ejection fraction between January 2017 and December 2021 were enrolled in this retrospective study. MACE was defined as the composite of death and re-hospitalization for ADHF within 6 months of index hospitalization. All-cause mortality and MACE were assessed with respect to relationships with eosinophil indices, including neutrophil-to-eosinophil ratio (NER), leukocyte-to-eosinophil ratio (LER), eosinophil-to-lymphocyte ratio (ELR), and eosinophil-to-monocyte ratio (EMR). Results: NER and LER were significantly higher in subjects with MACE. Absolute eosinophil, lymphocyte and basophil count, hemoglobin, serum Na+, albumin, and CRP, and EMR and ELR were significantly lower in subjects with MACE compared to those without. NT-proBNP (OR: 1.682, 95% CI: 1.106−2.312, p = 0.001), Na+ (OR: 0.932, 95% CI: 0.897−0.969, p < 0.001), NER (OR: 2.740, 95 % CI: 1.797−4.177, p < 0.001), LER (OR: 2.705, 95% CI: 1.752−4.176, p < 0.001), EMR (OR:1.654, 95% CI 1.123−2.436, p = 0.011), ELR (OR: 2.112, 95% CI 1.424−3.134, p < 0.001), and eosinophil count (OR: 1.833, 95% CI 1.276−2.635) were independent predictors for development of MACE. Conclusions: Patients with ADHF and reduced ejection fraction who developed MACE within the first six months of index hospitalization had lower levels of absolute eosinophil and lymphocyte counts, and EMR and ELR values, whereas NER and LER were higher compared to those without MACE. The eosinophil indices were independently associated with mortality and MACE development. The eosinophil indices may be used to estimate MACE likelihood with acceptable sensitivity and specificity.
Keywords: acute decompensated heart failure with reduced ejection fraction; eosinophil indices; mortality.