ObjectiveTo investigate the value of neutrophil/lymphocyte ratio (NLR) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) by detecting the relationship between NLR and other well-known inflammatory biomarkers.MethodsRetrospective study of 610 AECOPD cases was performed. In order to analyze the influence of NLR level on disease condition, treatment plan and prognosis, the clinical data with acute exacerbation were collected and the value of NLR in AECOPD were analyzed.ResultsThe level of NLR was higher in the group with pneumonia than that in the non-pneumonia group (P<0.05), and the more severe the pulmonary inflammation, the higher the NLR level (P<0.05). The level of NLR was higher in the group with heart failure and the group treated with ventilator and glucocorticoid (P<0.05). The NLR level was higher in the group of hospital stay over 14 days than the group of hospital stay less than 14 days (P<0.05). The NLR value of the death group was higher than that of the survival group (P<0.05). With the increase of NLR value, the mortality rate in hospital increased gradually. Compared with C-reactive protein and interleukin-6, NLR had the highest odds ratio by binary regression analysis. Cutoff value of NLR was 5.92 by analysis of receiver-operating characteristic curve with a sensitivity of 88% and a specificity of 51%, and the area under the curve in predicting in-hospital death was 0.727 (OR=4.112, 95% confidence interval 0.609 - 0.849, P=0.02).ConclusionsNLR can be used as an inflammatory marker to evaluate the severity of AECOPD and to predict the prognosis.