Abstract: Abstract：Objective To investigate the predictive value of neutrophil-lymphocyte ratio (NLR) combined with procalcitonin (PCT) in the death of patients with bacterial infection of acute exacerbation of chronic obstructive pulmonary disease (COPD). Methods Data of 210 patients with bacterial infection (sputum culture found bacteria at least twice) of acute exacerbation of COPD were analyzed retrospectively. The patients were divided into survival group (n=188) and nonsurvival group (n=22) according to the survival status at the time of discharge. Clinical data and laboratory results were compared between the two groups. The risk factors for death was analyzed by Logistic regression model, and predictive values of NLR, PCT and NLR combined with PCT in the death of patients with bacterial infection of acute exacerbation of COPD were analyzed by receiver operating characteristic (ROC) curve. Results Compared with survival group, the white blood cell count (WBC), neutrophil count (NEU), NLR, PCT, C-reactive protein (CRP) and arterial blood carbon dioxide partial pressure [ p(CO2) ] were significantly higher in non-survival group, while pH value and albumin were significantly lower in non-survival group (P＜0.05). Logistic regression analysis showed that the elevated NLR (OR=1.329, 95%CI:1.106-1.597) and PCT (OR=1.306, 95% CI:1.012-1.685) were high risk factors for death in patients. The ROC curve showed that the area under the curve (AUC) of the NLR, PCT, predictive regression model of NLR combined with PCT were greater than 0.7. And their specificities were 0.739, 0.564, and 0.702, the sensitivities were 0.727, 0.909, and 0.909. Conclusion Both NLR and PCT have preferably good predictive values for death in patients with bacterial infection of acute exacerbation of COPD. The predictive value is higher when the NLR and PCT were evaluated together.

Key words: pulmonary disease, chronic obstructive, acute disease, diagnosis, differential, sensitivity and specificity, neutrophil to lymphocyte ratio, procalcitonin