NPPB and chronic obstructive pulmonary disease: A meta-analysis assessing NT-proBNP levels in patients with COPD showed that NT-proBNP levels were significantly higher in patients with COPD combined with pulmonary hypertension and heart failure (HF) compared with those with COPD alone, whereas in patients with HF combined with COPD, NT-proBNP levels did not differ significantly from those in patients with isolated HF [4,25].