Association of pro-brain natriuretic peptide with degree of severity and prognostic outcome in patients with acute exacerbation of chronic obstructive pulmonary disease

Background: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a major cause of morbidity and mortality. N-terminal pro-brain natriuretic peptide (NT-proBNP) is an established biomarker of heart failure, but its association with AECOPD severity in patients without overt cardiac disease remains unclear. The objective is to assess the association between NT-proBNP levels, disease severity, and prognostic outcomes in patients with AECOPD. Methods: This cross-sectional study was conducted at the Department of Respiratory Medicine, NIDCH, Dhaka, Bangladesh, from July 2018 to June 2019. Seventy patients with established COPD admitted with acute exacerbation were enrolled through purposive sampling. Demographic and clinical data, SpO₂, arterial blood gas parameters, pulmonary artery systolic pressure (PASP), mMRC dyspnea grade, and NT-proBNP levels were recorded. Data were analyzed using chi-square tests, multivariate logistic regression, and Pearson correlation. Statistical significance was set at p<0.05. Results: The mean age was 61.77±8.91 years, and 95.7% of participants were male. Elevated NT-proBNP levels were observed in 74.3% of patients. Multivariate logistic regression identified mMRC dyspnea grade as the only independent factor significantly associated with elevated NT-proBNP (OR=7.457, 95% CI: 1.772–31.370; p=0.006). Significant correlations were reported between NT-proBNP and SpO₂, pH, PCO₂, and PO₂. Smoking exposure of 21–30 pack-years was also significantly associated with elevated NT-proBNP (p=0.042). Conclusions: Elevated NT-proBNP levels were associated with greater dyspnea severity and several respiratory parameters in patients with AECOPD, suggesting potential value in assessing disease severity. Further prospective studies are needed to establish its prognostic utility.