EDN1 and pulmonary arterial hypertension: To explore the correlation between high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), endothelin-1 (ET-1), and chronic obstructive pulmonary disease combined with pulmonary hypertension (COPD-PH), a total of 112 COPD patients admitted to our hospital from July 2017 to December 2020 were analyzed prospectively, of which 57 patients combined with PH were enrolled in the research group and the other 55 patients without PH were enrolled in the control group.