Comparative Analysis Of Clinical Characteristics And Pulmonary Function Among COPD Patients With Different Bronchodilator Responsiveness

Objective:To analyze whether there are differences in clinical characteristics and pulmonary function indexes among COPD patients with different bronchodilator responsiveness（BDR）,and to explore the clinical significance of BDR in COPD patients.Methods:109 patients with stable COPD admitted from January 2020 to December 2021 were collected.According to the responsiveness to bronchodilator,all patients were divided into four groups:○1 FVC-BDR:BDR in FVC but no BDR in FEV₁,○2 FEV₁-BDR:BDR in FEV₁but no BDR in FVC,○3 Combined-BDR:BDR in both FVC and FEV₁and○4 No-BDR:no BDR in either FVC or FEV₁.There were only 5 patients in group FEV₁-BDR,so they were not involved in the follow-up statistical process.Clinical characteristics（including CAT score,m MRC and GOLD grade）,pulmonary function indexes（including ventilatory function,lung volume,diffusion function,airway resistance）,and airway inflammation （including Fe NO and Ca NO）of these patients were compared.The clinical significance of BDR in COPD patients was discussed.Results:1.There were 22 cases in group FVC-BDR（20.18%）,5 cases in group FEV₁-BDR（4.59%）,30 cases in group Combined-BDR（27.52%）and 52 cases in group No-BDR（47.71%）.Compared with group FVC-BDR and group No-BDR,BMI in group Combined-BDR was higher（P<0.05）.Compared with group Combined-BDR and group No-BDR,m MRC and GOLD grade in group FVC-BDR were higher（P<0.01）.There were no significant differences in age,sex,smoking index,CAT score,and allergy among the group FVC-BDR,Combined-BDR,No-BDR（P>0.05）.2.Compared with group Combined-BDR and group No-BDR,FVC,FVC%,FEV₁,FEV₁%,FEV₁/FVC and FEV₁/VC before and after bronchial dilation test in group FVC-BDR were lower and MMEF%,MEF_50%,MEF_25%were lower（P<0.01）.There were no significant differences between the group Combined-BDR and No-BDR（P>0.05）.3.Compared with group Combined-BDR,D_LCO%,VC%and IC%in group FVC-BDR were lower（P<0.05）.Compared with group No-BDR,VC%,IC%in group FVC-BDR were lower and RV%,RV/TLC%were higher（P<0.01）.Compared with group No-BDR,RV%,TLC%,RV/TLC%,FRC%in group Combined-BDR were higher（P<0.01）.4.Compared with group No-BDR,R5-R20 delta in group FVC-BDR were higher（P<0.05）.Compared with group No-BDR,R5,R5%and R20%in group Combined-BDR were higher（P<0.05）.There were no significant differences between the group FVC-BDR and Combined-BDR（P>0.05）.5.Compared with group No-BDR,Fe NO,Ca NO in group Combined-BDR were higher（P<0.001）.There were no significant differences between the group FVC-BDR and No-BDR（P>0.05）.6.Volume bronchodilator responsiveness was negative correlated with small airway dysfunction.The higher the FVC improvement rate,the lower the MMEF%,MEF_50%, MEF_25%（r=-0.444,-0.386 and-0.340,respectively）.Conclusion:1.The clinical characteristics,pulmonary function and airway inflammation among COPD patients with different bronchodilator responsiveness are different.Bronchial dilation test may be an important tool to identify COPD phenotype2.Patients who showed volume bronchodilator responsiveness would show more severe dyspnea,higher GOLD,worse ventilation and diffusion function,more severe hyperinflation and small airway dysfunction.Patients who showed volume and flow bronchodilator responsiveness would show higher airway resistance and more severe airway inflammation.Both of them would be unique phenotypes of COPD patients,which need more attention;3.Volume bronchodilator responsiveness was correlated with small airway dysfunction.The higher the FVC improvement rate,the lower the MMEF%,MEF_50%,MEF_25%（r=-0.444,-0.386 and-0.340,respectively）.