Prognostic and diagnostic significance of copeptin in acute exacerbation of chronic obstructive pulmonary disease and acute heart failure: data from the ACE 2 study

BACKGROUND: Copeptin is a novel biomarker that predicts mortality in lower respiratory tract infections and heart failure (HF), but the diagnostic value of copeptin in acute dyspnea and the prognostic significance of copeptin in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is not clear. METHOD: We determined copeptin and NT-proBNP concentrations at hospital admission in 314 patients with acute dyspnea who were categorized by diagnosis. Survival was registered after a median follow-up of 816 days, and the prognostic and diagnostic properties of copeptin and NT-proBNP were analyzed in acute HF (n = 143) and AECOPD (n = 84) separately. RESULTS: The median concentration of copeptin at admission was lower in AECOPD compared to acute HF (8.8 [5.2-19.7] vs. 22.2 [10.2-47.9]) pmol/L, p < 0.001), but NT-proBNP discriminated acute HF from non-HF related dyspnea more accurately than copeptin (ROC-AUC 0.85 [0.81-0.89] vs. 0.71 [0.66-0.77], p < 0.0001). Adjusted for basic risk factors, increased copeptin concentrations predicted mortality in AECOPD (HR per log (ln) unit 1.72 [95% CI 1.21-2.45], p = 0.003) and acute HF (1.61 [1.25-2.09], p < 0.001), whereas NT-proBNP concentrations predicted mortality only in acute HF (1.62 [1.27-2.06], p < 0.001). On top of a basic model copeptin reclassified a significant proportion of patients into a more accurate risk strata in AECOPD (NRI 0.60 [0.19-1.02], p = 0.004) and acute HF (0.39 [0.06-0.71], p = 0.020). CONCLUSION: Copeptin is a strong prognostic marker in both AECOPD and acute HF, while NT-proBNP concentrations predict mortality only in patients with acute HF. NT-proBNP levels are superior to copeptin levels to diagnose acute HF in patients with acute dyspnea.