Significance of NT-pro-BNP in acute exacerbation of COPD patients without underlying left ventricular dysfunction.

BACKGROUND

B-type natriuretic peptide (BNP) and the N-terminal fragment of pro-BNP (NT-pro-BNP) are established biomarkers of heart failure. Increased levels of natriuretic peptide (NP) have been associated with poor outcomes in acute exacerbation of COPD (AECOPD); however, most studies did not address the conditions that can also increase NT-pro-BNP levels. We aimed to determine if NT-pro-BNP levels correlate with outcomes of AECOPD in patients without heart failure and other conditions that can affect NT-pro-BNP levels.

METHODS

We conducted a retrospective study in patients hospitalized for AECOPD with available NT-pro-BNP levels and normal left ventricular ejection fraction. We compared patients with normal and elevated NT-pro-BNP levels and analyzed the clinical and outcome data.

RESULTS

A total of 167 of 1,420 (11.7%) patients met the study criteria. A total of 77% of male patients and 53% of female patients had elevated NT-pro-BNP levels (=0.0031). NT-pro-BNP levels were not associated with COPD severity and comorbid illnesses. Log-transformed NT-pro-BNP levels were positively associated with echocardiographically estimated right ventricular systolic pressure (=0.3658; 95% confidence interval [CI]: 0.2060-0.5067; <0.0001). Patients with elevated NT-pro-BNP levels were more likely to require intensive care (63% vs 43%; =0.0207) and had a longer hospital length of stay (=0.0052). There were no differences in the need for noninvasive positive pressure ventilation (=0.1245) or mechanical ventilation (=0.9824) or in regard to in-hospital mortality (=0.5273).

CONCLUSION

Patients with AECOPD and elevated NT-pro-BNP levels had increased hospital length of stay and need for intensive care. Based on our study, serum NT-pro-BNP levels cannot be used as a biomarker for increased mortality or requirement for invasive or noninvasive ventilation in this group of patients.