NPPB and chronic obstructive pulmonary disease: BMI body mass index, mPAP mean pulmonary artery pressure, PVR pulmonary vascular resistance, CI cardiac index, FEV1 forced expiratory volume in 1 s, FEV1/FVC forced expiratory volume in 1 s to forced vital capacity ratio, GOLD Global Initiative for Chronic Obstructive Lung Disease, DLCO diffusing capacity of the lung for carbon monoxide, RBC red blood cell count, RDW red blood cell distribution width, NT-proBNP N-terminal pro B-type natriuretic peptide, CRP C-reactive protein, NA not applicable, pred predicted