Diagnostic and prognostic value of urine NT-proBNP levels in heart failure patients

Background: Plasma NT-proBNP levels are sensitive markers of ventricular dysfunction. However, studies of natriuretic peptides in urine are limited. Aims: To compare urine and plasma NT-proBNP levels and to investigate the diagnostic and prognostic value of urine levels in heart failure (HF). Methods: Urinary and plasma NT-proBNP levels were measured in 96 HF patients and 20 control subjects. The patients were functionally classified according to the NYHA criteria. Results: Urine NT-proBNP was higher in HF patients than in control subjects (94 +/- 31 pg/ml vs. 67 +/- 6 pg/ml, p < 0.0001), correlating with plasma NT-proBNP levels (r=0.78, p < 0.0001). Urinary levels were elevated in the more severe functional classes and diminished in obese patients. Urine NT-proBNP was a good tool for diagnosis of HF, the area under the curve (AUC) being 0.96 +/- 0.02 (p < 0.0001), and for predicting 12-month cardiac events (p = 0.011). To determine the prognostic power of urinary NT-proBNP in detecting 12-month cardiac mortality, we obtained an AUC of 0.75 +/- 0.10 (p=0.015). Conclusion: Urinary NT-proBNP, a relatively simple non-invasive test, is a new candidate marker for the diagnosis and evaluation of prognosis in HF and for the characterization of functional status in these patients. (c) 2005 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.