Objectives This study compared the prognostic value of a marker, C-terminal part of the arginine vasopressin prohormone (Copeptin), with N-terminal B-type natriuretic peptide (NT-proBNP) in patients with severe acute decompensated heart failure.

Methods We conducted a prospective, observational cohort study in a tertiary care hospital and enrolled 129 patients with sever acute decompensated heart failure (NYHA Class III/IV). Clinicians were blinded to investigational markers except NT-proBNP, and the study participants were followed for 90-day. The end point was a composite of cardiovascular death or re-hospitalisation due to decompensated heart failure.

Results Of the 129 patients enrolled, 47 reached end point and 82 in stable condition during follow-up. In patients in stable condition the NP-proBNP and copeptin levels were 3275 (1008.8–8827.0) pg/mL and 0.79 ± 0.30 ng/mL. In patients reach the adverse endpoint the two biomarkers levels were 6656 (2919.0–15701.0) pg/mL and 0.92 ± 0.31 ng/mL. For those two markers, values are significantly higher in adverse endpoint patients than in stable condition patients (P = 0.003, P = 0.022).

Receiver operating characteristic curve (ROC) curve analysis showed that the areas under curve (AUCs) for the prediction of 90-day adverse events were similar for copeptin 0.602 (SE, 0.052; 95% CI 0.499-0.705), NT-proBNP 0.659 (SE, 0.048; 95% CI 0.565-0.753) and their combination 0.670 (SE, 0.050; 95% CI 0.573-0.767). In survival analysis, Kaplan-Meier curve analyses showed that the predictive value of NT-proBNP for survival probability was superior (log-rank test for trend, P = 0.001) than copeptin (log-rank test for trend, P = 0.040). In multivariable Cox proportional-hazards regression analyses, increased NT-proBNP, copeptin plasma concentrations were significant independent predictors of adverse events.

Conclusions The study provides evidence that copeptin measurements have similar predictive properties compared with NT-proBNP determinations for 90-day adverse events in severe acute decompensated heart failure, and copeptin may not provide superior 90-day prediction compared to NT-proBNP.