NT-proBNP in stable COPD and future exacerbation risk: Analysis of the SPIROMICS cohort.

BACKGROUND: High N-terminal pro-brain natriuretic peptide (NT-proBNP) during COPD exacerbations is associated with worse clinical outcomes. The prognostic value of NT-proBNP measured during clinical stability has not been well characterized.

METHODS: We studied SPIROMICS participants 40-80 years of age with COPD GOLD spirometric stages 1-4. The association between baseline NT-proBNP and incident COPD exacerbations within one year of follow-up was tested using zero-inflated Poisson regression models adjusted for age, gender, race, body mass index, current smoking status, smoking history, FEV1 percent predicted, COPD Assessment Test score, exacerbation history, total lung capacity on chest CT and cardiovascular disease (any of coronary artery disease, myocardial infarction or congestive heart failure).

RESULTS: Among 1051 participants (mean age 66.1 years, 41.4% women), mean NT-proBNP was 608.9 pg/ml. Subjects in GOLD stage D had the highest mean NT-proBNP. After one year of follow-up, 268 participants experienced one or more COPD exacerbations. One standard deviation increase in baseline NT-proBNP was associated with a 13% increase in the risk of incident exacerbations (incident risk ratio 1.13; 95% CI 1.06-1.19; p < 0.0001). This association was maintained in participants with and without cardiovascular disease.

CONCLUSION: Baseline NT-proBNP in COPD is an independent predictor of respiratory exacerbations, even in individuals without overt cardiac disease. The impact of detection and treatment of early cardiovascular dysfunction on COPD exacerbation frequency warrants further investigation.