EDN1 and chronic obstructive pulmonary disease: The research group showed significantly higher serum hs-CRP, IL-6, and ET-1 and significantly lower IL-10 expression than the control group (all P < 0.05); serum hs-CRP, IL-6, and ET-1 were negatively correlated with PaO2, FEV1, FVC, and FEV1/FVC and positively correlated with PaCO2; IL-10 was positively correlated with PaO2, FEV1, FVC, and FEV1/FVC and negatively correlated with PaCO2; hs-CRP, IL-6, and ET-1 were positively correlated with COPD-PH severity, and IL-10 was negatively correlated with it.