Association Between Neutrophil Percentage to-Albumin Ratio, Neutrophil to-Lymphocyte Ratio, Platelet-to Lymphocyte Ratio and in-Hospital Mortality in Elder Patients with Bloodstream Infections.

Background: Bloodstream infections (BSI) is one of the major complications in elder inpatients, which is closely related to inflammation. Neutrophil percentage-to-albumin ratio (NPAR), Neutrophil-to-lymphocyte ratio (NLR), and Platelet-to-lymphocyte (PLR) are convenient predictors of inflammation and poor prognosis for a wide range of diseases. However, the association of NPAR, NLR and PLR with in-hospital mortality in elder inpatients with BSI are unclear. This study aimed to investigate the association and the predictive value of NPAR, NLR and PLR with in-hospital mortality.

Methods: This study included older patients with BSI who were hospitalized in a large healthcare center in Beijing from December 2011 to January 2024. Kaplan-Meier curves and Cox regression analysis were used to explore the association of NPAR, NLR and PLR with in-hospital mortality. Restricted cubic spline analysis and Receiver operating characteristics (ROC) were performed to access the dose-response relationship and predictive value of NPAR, NLR and PLR with in-hospital mortality, respectively.

Results: A total of 511 older patients with BSI were included in this study, with a mean age of 89.9±8.5 years, of which 85 deaths occurred during hospitalization (16.6%). After adjustment, the continuous NPAR level was associated with increased risk of in-hospital mortality (hazard ratio [HR] = 1.08, 95% confidence interval [CI]: 1.05, 1.12). The third tertile group of NPAR significantly increased the risk of in-hospital mortality compared to the first tertile group of NPAR (HR = 3.36, 95% CI: 1.87, 6.02). However, no association between NLR, PLR and in-hospital mortality was found. The area under the ROC curve of NPAR, NLR, and PLR for predicting mortality were 0.681 (95% CI: 0.615-0.747), 0.666 (95% CI: 0.598-0.733), and 0.510 (95% CI: 0.420-0.559), respectively.

Conclusion: Elevated NPAR was associated with higher risk of in-hospital mortality in older patients with BSI. NPAR may serve as a convenient and simple prognostic indicator.