Estimation of Endothelin Levels in Chronic Obstructive Pulmonary Disease Patients with Pulmonary Hypertension: A Clinical Insight

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major global health issue, with pulmonary hypertension (PH) as a severe complication linked to increased morbidity and mortality. Endothelin-1 (ET-1) is a vasoconstrictor peptide and a potential biomarker for PH in COPD due to its role in vascular remodeling and hemodynamic stress. OBJECTIVES: This study aimed to assess serum ET-1 levels in COPD patients with and without PH to evaluate its correlation with hemodynamic and metabolic parameters and evaluate its diagnostic potential. METHODOLOGY: A cross-sectional study enrolled 90 subjects (46 COPD with PH, 24 COPD without PH, 20 controls) from January 2023 to December 2024. COPD was confirmed via spirometry (forced expiratory volume in 1 s/forced vital capacity <0.70) and PH defined as mean pulmonary artery pressure (MPAP) >20 mmHg by right heart catheterization or echocardiography. Serum ET-1 was measured using enzyme-linked immunosorbent assay. Data included clinical history, spirometry, hemodynamics, and hemoglobin A1c (HbA1c). Statistical analysis involved analysis of variance, post-hoc tests, bivariate correlations and multivariate regression (P < 0.05 significant). RESULTS: ET-1 levels were significantly elevated in COPD with PH (26.6 ± 16.87 pg/mL) versus COPD without PH (17.96 ± 18.43 pg/mL) and controls (3.3 ± 1.48 pg/mL, P < 0.001). MPAP (27.46 ± 5.62 mmHg vs. 15.02 ± 1.28 and 15.23 ± 1.17 mmHg, P < 0.001) and right atrial (RA) pressure (12.17 ± 2.76 vs. 5.75 ± 0.87 and 5.7 ± 0.82 mmHg, P < 0.001) distinguished the PH group. ET-1 correlated with MPAP (P = 0.001), RA pressure (P = 0.002), and HbA1c (P = 0.003), with HbA1c as an independent predictor (odds ratio: 4.66, 95% confidence interval 0.748-8.58, P = 0.0203). No correlations were observed with smoking (P = 0.83) or lung function (P = 0.295). Echocardiographic markers (P < 0.014) supported PH diagnosis. CONCLUSION: Elevated ET-1 marked PH severity in COPD, with a novel metabolic link to HbA1c, which suggested its utility as a non-invasive diagnostic tool.