N-terminal-pro-B-type natriuretic peptide (NT-proBNP): reference range for Chinese apparently healthy people and clinical performance in Chinese elderly patients with heart failure.

BACKGROUND: N-terminal-pro-B-type natriuretic peptide (NT-proBNP) has been found to be a useful marker for the diagnosis of heart failure (HF) and left ventricular systolic dysfunction. We established a reference range for Chinese apparently healthy people based on age and gender and evaluated the clinical performance of NT-proBNP in the diagnosis of asymptomatic and symptomatic HF.

METHODS: A group of 442 apparently healthy subjects were enrolled for reference range study. For the clinical performance study, serum NT-proBNP and clinical data were analyzed in 111 elderly patients with HF and 60 normal elderly controls. Serum NT-proBNP was measured by the Roche Elecsys 2010 immunoassay analyzer.

RESULTS: NT-proBNP reference range in Chinese people based on age and gender was <83.72 ng/l for men and <131.6 ng/l for women aged 60 years, which were lower than those for western countries. NT-proBNP had a close correlation with New York Heart Association (NYHA) classification (r=0.818) and LVEF (r=-0.636). The ROC curve analysis revealed an AUC of 0.921 for the diagnosis of HF, 0.840 for asymptomatic HF (NYHA I) and 0.951 for symptomatic HF (NYHA II-IV). The optimal cutoff values for detecting HF, asymptomatic HF and symptomatic HF were 102.2, 102.2, and 204.8 ng/l, respectively. NT-proBNP had high positive predictive value (PPV) for the diagnosis of HF (96.8%), asymptomatic HF (90.3%) and symptomatic HF (90.9%), but low negative predictive value (NPV) for diagnosing HF and asymptomatic HF (74.0% and 78.1%, respectively) except symptomatic HF (93.3%).

CONCLUSIONS: Chinese people have lower reference range of serum NT-proBNP. NT-proBNP assay has a good clinical performance for the diagnosis of symptomatic HF but is not suitable as a screening test for HF.