EDN1 and chronic obstructive pulmonary disease: First, the two groups were compared in hs-CRP, IL-6, IL-10, and ET-1 expression, and it turned out that the research group showed significantly higher serum hs-CRP, IL-6, and ET-1 and significantly lower IL-10 expression than the control group, which indicated that COPD patients with PH and COPD patients without PH showed a significant difference in hs-CRP, IL-6, IL-10, and ET-1 expression and further suggested that the onset of COPD is related to systemic inflammatory response.