Unveiling MicroRNA-21 as a non-invasive diagnostic biomarker in chronic obstructive pulmonary disease-associated pulmonary hypertension: Comparative insights with NT-proBNP

BACKGROUND: Pulmonary hypertension (PH) is a fatal complication of chronic obstructive pulmonary disease (COPD) that worsens its prognosis. However, the associated diagnostic markers are uncertain. We assess the diagnostic utility of microRNA-21 (miR-21) and NT-proBNP for PH diagnosis in COPD patients. METHODS: We selected three groups of participants: Group 1 consisted of 25 patients with COPD who did not have PH (COPD); Group 2 included 35 patients with COPD and PH (COPD-PH); and Group 3 comprised 30 healthy controls. Demographic, spirometric, echocardiographic-Doppler study, and biochemical variables were recorded and compared among these three groups. Serum miR-21 was measured by quantitative real-time PCR. RESULTS: Serum miR-21 level in COPD-PH patients was significantly higher compared with that in COPD patients and controls (P < 0.001). Compared with the COPD group, the COPD-PH group had greater miR-21 and brain natriuretic peptide (BNP) levels but significantly reduced forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), tricuspid annular plane systolic excursion (TAPSE), 6-minute walk test, and right ventricular (RV) functional parameters. Receiver Operating Characteristic curve analysis revealed that miRNA-21 had good diagnostic value for PH diagnosis in COPD patients, with an area under the curve (AUC) of 1.000, 100% sensitivity, and 100% specificity at a cutoff >7.94. While NT-proBNP demonstrated good accuracy, with an AUC of 0.936, sensitivity of 88.6%, and specificity of 88% at a cutoff >390.1 pg/mL. CONCLUSION: miR-21 may serve as a useful and reliable biomarker for diagnosing PH in COPD patients, outperforming the traditional biomarker NT-proBNP.