Predictive Value of Neutrophil-To-Lymphocyte Ratio and Systemic Immune-Inflammation Index in the Prognosis of Sepsis-Related Acute Respiratory Distress Syndrome

Abstract

Aims/Background The neutrophil-to-lymphocyte ratio (NLR) was an independent influence factor for mortality in acute respiratory distress syndrome (ARDS). The systemic immune-inflammation index (SII) is a predictive indicator for sepsis. This study was designed to evaluate the predictive value of combined NLR and SII in sepsis-related ARDS. Methods Patients with sepsis-related ARDS (n = 112), admitted to Pingyang Hospital of Wenzhou Medical University from January 2022 to January 2025, were obtained for retrospective analysis. A survivor group (n = 62) and a non-survivor group (n = 50) were formed based on 28-day survival status. Neutrophil, lymphocyte, and platelet counts were detected, and NLR and SII were subsequently calculated. Logistic regression analysis and receiver operating characteristic (ROC) curves were performed to analyze the influences of NLR and SII in the prognosis of sepsis-related ARDS. Results Non-survivor group has longer intensive care unit (ICU) length of stay, higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score and white blood cell (WBC) count, and lower lymphocyte count than those of survivor group (p = 0.001, 0.032, 0.028, 0.004, respectively). Both NLR and SII values were elevated in the non-survivor group (p < 0.001). Furthermore, APACHE II score (odds ratio (OR): 1.150, 95% confidence interval (CI): 1.004-1.317, p = 0.044), ICU length of stay (OR: 1.147, 95% CI: 1.017-1.294, p = 0.026), NLR (OR: 1.158, 95% CI: 1.068-1.255, p < 0.001), and SII >2090.37 (OR: 5.207, 95% CI: 1.800-15.064, p = 0.002) as independent prognostic risk factors. The combined NLR and SII had a superior predictive value (area under the curve (AUC): 0.808, 95% CI: 0.730-0.887, p < 0.001) compared to APACHE II score (AUC: 0.618, 95% CI: 0.503-0.733, p = 0.045), ICU length of stay (AUC: 0.679, 95% CI: 0.573-0.784, p = 0.001), NLR alone (AUC: 0.788, 95% CI: 0.701-0.875, p < 0.001), or SII alone (AUC: 0.748, 95% CI: 0.657-0.840, p < 0.001). The optimal cut-off values for APACHE II score, ICU length of stay, NLR, and SII were 19.5, 15.5, 26.13, and 2090.37, respectively. Conclusion The combination of NLR and SII provides a strong predictive value for the prognosis of sepsis-related ARDS.