Abstract:

Objective To study the relationship between sputum cytology and prognosis in patients with acute exacerbation of COPD and provide theoretical basis for accurate diagnosis and treatment of different inflammatory phenotype in COPD. Methods A retrospective observational cohort study was carried out in a tertiary teaching hospital from February 2016 to July 2018. A total of 291 COPD patients with acute exacerbation were admitted in department of pulmonary and critical care medicine. The diagnosis met the requirements described in the Global Initiative for Chronic Obstructive Lung Disease（GOLD）2016 Updated edition and the patients had no other respi⁃ ratory diseases. Sputum inflammatory cells counts and blood routine tests，NLR were conducted and performed on the day of admission and lung functions were measured when the disease was stabilized. The follow⁃up records were made 3 months，1 year and 2 years after the discharge respectively. Statistical analysis of the patient′s condition， treatment，readmission，and time of death were also made. Results The percentage of sputum neutrophils and sputum macrophages was statistically different between GOLD stage 1 and 2 group and GOLD stage 3 and 4 group（P < 0.05）. The recurrence of acute exacerbation in patients within 3 months or 1 year after discharge，the percentage of sputum macrophages，the neutrophil count，blood lymphocyte and NLR were statistically different （P < 0.05）；the percentage of sputum neutrophils，sputum macrophages，blood neutrophils，blood lymphocyte and NLR were statistically different between COPD patients with acute exacerbation who died during the 2⁃year fol⁃ low⁃up period and those COPD survivals（P < 0.05）. ROC curve analysis suggested that the AUC of NLR for predicting death within two years of discharge was 0.676（95%CI：0.597 ~ 0.756，P < 0.05）；the cut ⁃off point 2.6；the sensitivity 80.7% and the specificity 50.2%. The AUC of sputum neutrophils was 0.635（95%CI：0.557 ~ 0.712，P < 0.05）；the cut⁃off point 90.6%；the sensitivity 61.4% and the specificity 62.0%. Conclusion The per⁃ centage of sputum neutrophils and sputum macrophages induced by acute exacerbation may be an indicator to eval⁃ uate the severity of COPD. The percentage of sputum neutrophils and blood NLR induced by acute exacerba⁃ tion have certain value in evaluating the prognosis of COPD patients. 

Key words:

chronic obstructive pulmonary disease, acute exacerbation, sputum neutrophils, neutro? phil?to?lymphocyte ratio, prognosis