Evaluation of the prognostic value of the platelet, neutrophil, monocyte, basophil, and eosinophil to lymphocyte ratios in patients with severe community-acquired pneumonia (SCAP)

Abstract

Abstract Background: Severe community-acquired pneumonia (SCAP) is a serious respiratory inflammation disease with high morbidity and mortality. This study aimed to evaluate the prognostic value of the platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), basophil-to-lymphocyte ratio (BLR) and eosinophil-to-lymphocyte ratio (ELR) in patients with severe community-acquired pneumonia (SCAP). Methods: The study retrospectively included 554 patients with SCAP and healthy volunteers, and the clinical data were obtained from the electronic patient record (EMR) system. The primary outcome was in-hospital mortality, and the secondary outcomes included hospital length of stay (LOS), overall survival (OS), admission to the intensive care unit (ICU), ICU LOS, and ICU mortality. The correlations of systemic inflammatory factors (PLR, NLR, MLR, BLR, and ELR) with primary and secondary outcomes were analyzed. Results: In the patients with SCAP, both NLR and BLR were significant but independent risk factors for in-hospital mortality; NLR was negatively correlated with hospital LOS while ELR was positively correlated with hospital LOS; both increased NLR and BLR were associated with reduced OS, while increased ELR was associated with improved OS; increased PLR, NLR, MLR, and BLR were all correlated with elevated ICU admission rates, while increased ELR was correlated with reduced ICU admission rates; ELR was positively correlated with ICU LOS, whereas PLR, NLR, MLR, or BLR had no significant correlation with ICU LOS; both higher NLR and BLR were associated with elevated ICU mortality; PLR, NLR, and MLR were improved while ELR was lowered in patients with SCAP compared to healthy volunteers; PLR, NLR, and MLR were reduced while ELR was elevated when the patients were in recovery after treatment. Furthermore, BLR was elevated in patients with SCAP compared with healthy volunteers. Conclusions: NLR and BLR were useful biomarkers for clinical outcomes in patients with SCAP.