ObjectiveTo explore the clinical characteristics and long term mortality of patients with eosinophilic and neutrophilic chronic obstructive pulmonary disease (COPD) exacerbations requiring hospital admission.MethodsA retrospective review of the clinical data and long-term follow up was performed for 510 patients with first diagnosis of acute exacerbation of COPD (AECOPD) requiring hospital admission between January 2015 and December 2016. The follow-up was completed in January 1, 2020. These patients were divided into three groups according to routine blood test: an eosinophilic exacerbation group, with peripheral blood eosinophils >2%; a neutrophilic exacerbation group, with peripheral blood neutrophils >65% or leukocytes >11×109/L; a paucigranulocytic exacerbation group, any case did not belong to the above two groups. The differences of clinical characteristics were compared among three groups. Cox regression model was used for analysis of independent risk factors of all-cause mortality of AECOPD patients.ResultsA total of 510 AECOPD patients were enrolled (180 eosinophilic, 273 neutrophilic and 57 paucigranulocytic, respectively). Compared with the neutrophilic exacerbation group, the eosinophilic exacerbation group had shorter time since onset of symptoms, the lower proportion of comorbid heart failure, the lower proportion of mechanical ventilation, dual antibiotics and systematic corticosteroid treatment, the shorter length of hospitalization and lower hospital mortality (all P<0.05). The average follow-up duration was 41 months for 485 AECOPD patients who completed long term follow-up. Compared with the eosinophilic exacerbation group, the neutrophilic exacerbation group was associated with a higher long-term mortality of AECOPD (HR=1.691, 95%CI 1.205 - 2.373, P=0.002).ConclusionCOPD patients with neutrophilic exacerbations have more serious clinical features and higher mortality than those with eosinophilic exacerbations.
