Abstract
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 SCAP. The study retrospectively included 554 patients with SCAP, 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 ICU, ICU LOS, and ICU mortality. The results showed that both NLR and BLR were significant but not independent prognostic factors for in-hospital mortality; NLR was negatively correlated with hospital LOS while ELR was positively correlated with hospital LOS; both increased NLR and increased 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 a reduced ICU admission rate; ELR was positively correlated with ICU LOS; both higher NLR and higher BLR were associated with increased ICU mortality. In summary, NLR and BLR were useful prognostic factors for clinical outcomes in patients with SCAP.