To evaluate the prognostic value of neutrophil to albumin ratio (NAR) and lactic acid on 28-day mortality of patients with septic shock.

Clinical data of 118 patients with septic shock admitted to the ICU of Nanjing First Hospital from October 2017 to October 2019 were retrospectively analyzed. The age, sex, body mass index (BMI), acute physiology and chronic health evaluation (APACHE)Ⅱ score, sequential organ failure assessment (SOFA) score, C-reactive protein (CRP), procalcitonin, NAR, leukocyte count, red blood cell distribution width (RDW), lactic acid, ICU stay, mechanical ventilation time, continuous renal replacement therapy (CRRT), pulmonary infection, abdominal infection, urinary tract infection, blood transfusion infection, and 28-day death were recorded in all patients. Then they were included in the univariate Logistic regression analysis, and relative influencing factors were preliminarily screened and included in the multivariate Logistic regression analysis to obtain independent risk factors affecting 28-day mortality in patients with septic shock. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of NAR, lactic acid and their combination on 28-day mortality, and the areas under the curves (AUCs) were compared with the Z-test.

Univariate Logistic regression analysis showed that male [odds ratio (OR) = 0.345, 95% confidence interval (CI) (0.603, 3.357), P = 0.004], SOFA score [OR = 1.183, 95%CI (1.036, 1.350), P = 0.013], NAR [OR = 2.849, 95%CI (1.487, 5.457), P = 0.002], lactic acid [OR = 1.275, 95%CI (1.108, 1.467), P = 0.001], mechanical ventilation time [OR = 0.254, 95%CI (1.025, 1.223), P < 0.001], CRRT [OR = 4.585, 95%CI (1.737, 12.100), P = 0.002], pulmonary infection [OR = 0.282, 95%CI (0.898, 4.732), P < 0.001], abdominal infection [OR = 0.460, 95%CI (0.392, 1.989), P = 0.002] and urinary tract infection [OR = 0.464, 95%CI (0.201, 2.195), P < 0.001] were associated with 28-day mortality of patients with septic shock. When these factors were taken into account in the multiple Logistic regression analysis, the results showed that NAR [OR = 4.424, 95%CI (1.427, 13.717), P = 0.010], lactic acid [OR = 1.267, 95%CI (1.008, 1.594), P = 0.043], mechanical ventilation time [OR = 1.168, 95%CI (1.007, 1.356), P = 0.041] and CRRT [OR = 5.148, 95%CI (1.069, 24.794), P = 0.041] were independent risk factors for 28-day death. ROC curve analysis showed that NAR [AUC = 0.676, 95%CI (0.572, 0.780), P = 0.001], lactic acid [AUC = 0.696, 95%CI (0.592, 0.800), P < 0.001] and their combination [AUC = 0.759, 95%CI (0.699, 0.850), P < 0.001] had predictive values for 28-day death of patients with septic shock. In addition, the AUC of NAR and lactic acid combination was significantly higher than that of NAR (Z = 2.110, P = 0.035) and lactic acid (Z = 1.991, P = 0.047).

NAR and lactic acid are predictive for 28-day mortality of patients with septic shock, and their combination can improve the predictive value.