PT  - JOURNAL ARTICLE
AU  - Yang, Huajing
AU  - Wen, Xiang
AU  - Wu, Fan
AU  - Zheng, Youlan
AU  - Dai, Cuiqiong
AU  - Zhao, Ningning
AU  - Deng, Zhishan
AU  - Wang, Zihui
AU  - Peng, Jieqi
AU  - Xiao, Shan
AU  - Lu, Lifei
AU  - Huang, Jianhui
AU  - Yu, Shuqing
AU  - Yang, Changli
AU  - Chen, Shengtang
AU  - Zhou, Yumin
AU  - Ran, Pixin
TI  - Inter-relationships among neutrophilic inflammation, air trapping and future exacerbation in COPD: an analysis of ECOPD study
AID  - 10.1136/bmjresp-2022-001597
DP  - 2023 Apr 01
TA  - BMJ Open Respiratory Research
PG  - e001597
VI  - 10
IP  - 1
4099  - http://bmjopenrespres.bmj.com/content/10/1/e001597.short
4100  - http://bmjopenrespres.bmj.com/content/10/1/e001597.full
SO  - BMJ Open Resp Res2023 Apr 01; 10
AB  - Background The inter-relationships among neutrophilic airway inflammation, air trapping and future exacerbation in chronic obstructive pulmonary disease (COPD) remain unclear.Objective To evaluate the associations between sputum neutrophil proportions and future exacerbation in COPD and to determine whether these associations are modified by significant air trapping.Methods Participants with completed data were included and followed up to the first year in the Early Chronic Obstructive Pulmonary Disease study (n=582). Sputum neutrophil proportions and high-resolution CT-related markers were measured at baseline. Sputum neutrophil proportions were dichotomised based on their median (86.2%) to low and high levels. In addition, subjects were divided into the air trapping or non-air trapping group. Outcomes of interest included COPD exacerbation (separately any, severe and frequent exacerbation, occurring in the first year of follow-up). Multivariable logistic regressions were performed to examine the risk of severe exacerbation and frequent exacerbation with either neutrophilic airway inflammation groups or air trapping groups.Results There was no significant difference between high and low levels of sputum neutrophil proportions in the exacerbation in the preceding year. After the first year of follow-up, subjects with high sputum neutrophil proportions had increased risks of severe exacerbation (OR=1.68, 95% CI: 1.09 to 2.62, p=0.020). Subjects with high sputum neutrophil proportions and significant air trapping had increased odds of having frequent exacerbation (OR=3.29, 95% CI: 1.30 to 9.37, p=0.017) and having severe exacerbation (OR=2.72, 95% CI: 1.42 to 5.43, p=0.003) when compared with those who had low sputum neutrophil proportions and non-air trapping.Conclusions We found that subjects with high sputum neutrophil proportions and significant air trapping are prone to future exacerbation of COPD. It may be a helpful predictor of future exacerbation.Data are available upon reasonable request.