Abstract: Objective To investigate the clinical value and significance of sputum culture combined with granulocytic ratio (NLR) and interleukin-6 (IL-6) in the diagnosis of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. Methods Retrospective analysis of 160 AECOPD patients (125 sputum culture-negative cases and 35 sputum culture-positive cases) in Bozhou people's Hospital admitted and diagnosed March 2018~ February 2020 was performed. According to whether the AECOPD process with pulmonary heart disease, respiratory failure or pulmonary hypertension or other dangerous complications, the 125 patients with negative sputum culture were divided into simple group (67 cases) and complicated group (58 cases). Another 35 COPD stable patients were selected as control group. Comparison of blood routine and serum IL-6、hs-CRP, the general clinical data and laboratory indexes were collected and analyzed. Results （1） Comparisons among three groups, there were significantly differences in NLR and IL-6 levels (P<0.05), but no statistical difference in other indicators (P>0.05).（2） NLR in pairwise comparisons among three groups:comparison of AECOPD sputum culture negative group and positive group, we found that there was no statistical difference(P>0.05), but comparison with the control group,AECOPD sputum culture-negative group and positive group showed significant differences(P<0.05).（3） IL-6 level in pairwise comparisons in three groups:comparison with AECOPD sputum culture positive-group, AECOPD sputum culture negative group and the control group showed no statistical difference(P>0.05), but there was a significant difference between AECOPD sputum culture negative group and the control group (P<0.05). （4）In the AECOPD sputum culture-negative cases, there was no statistical significance between complicated group and simple group. （5）The ROC curve analysis of each inflammatory index factor in the sputum culturenegative group of AECOPD patients showed that the area of NLR and IL-6 under the curve of sputum culture negative patients was 0.720, 0.689. Conclusion The results of sputum bacteria culture combined with the expression level of NLR and IL-6 can assist in the diagnosis of AECOPD patients, especially for AECOPD patients without specific indicators in sputum bacteria culture negative.

Key words: Ratio of neutrophils to lymphocytes, Interleukin-6, Chronic obstructive pulmonary disease, Sputum bacterial culture