NPPB and chronic obstructive pulmonary disease: There were no significant differences between the ADHF groups in age, body mass index, hypertension, admission aminoterminal pro-B-type natriuretic peptide (NT-proBNP) levels, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVIDd), or several co-morbidities theorized to result in alterations in the exhaled metabolome (i.e., diabetes mellitus, chronic obstructive pulmonary disease).