Different expression about induced sputum cell sorting in the two main types of chronic obstructive pulmonary disease

The difference in expression of sputum cells types between the two main types of chronic obstructive pulmonary disease (COPD) is largely unknown. This study aims to investigate the difference and then wants to depend on sputum cells sorting to direct the treatment of COPD.

A total of 218 patients with stable COPD (FEV1 < 80%) were selected. Stable COPD patients (n = 218) were classified as eosinophilic (A phenotype) or noneosinophilic (B phenotype); sometimes, the subjects were separated into cough group (C phenotype) and dyspnea group (D phenotype). Cross-sectional analysis was conducted comparing demographics and clinical characteristics. Receiver-operating characteristic curve was used to assess predictive ability of sputum eosinophils for D phenotype.

The A phenotype showed a higher correlation with the patients complaining of presenting with dyspnea on exertion, the dyspnea group (D phenotype). The B phenotype showed a higher prevalence of those who cough and product sputum, this was cough group (C phenotype). Sputum eosinophil and macrophages counts were significantly higher in patients with dyspnea (n = 95) compared to those with cough (P < .05), and neutrophils were significantly lower in patients with dyspnea (n = 95) compared to those with cough (P < .05). Percentage sputum eosinophil count was predictive of dyspnea (D phenotype) COPD with area under curve (AUC) of 0.831 (95% confidence interval (CI) 0.77-0.89; P ≤ .001). Neutrophils were also predictive of dyspnea (D phenotype) COPD with AUC of 0.276 (95% CI 0.204-0.347; P ≤ .001).

These findings suggest that the morphological phenotypes of COPD show several clinical characteristics and different sputum cell sorting.