Urinary B-type natriuretic peptide levels in the diagnosis and prognosis of heart failure

Background: Plasma B-type natriuretic peptide (BNP) is a useful biomarker for diagnosis and prognosis of heart failure (HF); however, urine BNP has never been calculated. We sought to compare urinary and plasma BNP levels and to investigate the potential diagnostic and prognostic value of this peptide in HF. Methods and Results: Urine and plasma BNP levels were measured in 92 HF patients and 30 control subjects. Urinary BNP levels were higher in HF patients than in control subjects (P < .0001), correlating with plasma BNP levels (r = 0.64, P < .0001). Urine BNP was a good tool for the diagnosis of HF, the area under the curve (AUC) being 0.91 +/- 0.06 (P < .0001). Urinary BNP levels had prognostic power for cardiac events (cardiac admissions + mortality) with an odds ratio of 6.6 (P < .05). To determine the prognostic power of urinary BNP in detecting 12-month cardiac mortality, we obtained an AUC of 0.76 +/- 0.6 (P = .014). Conclusions: The data suggest that urine BNP is a new candidate marker for diagnosis and prognosis of HF mortality and cardiac events. This raises the possibility of using this relatively simple noninvasive test in primary care settings or in specific conditions where the collection of blood samples could be difficult.