Prognostic value of B-type natriuretic peptide and its amino-terminal proBNP fragment for cardiovascular events with stratification by renal function.

BACKGROUND: Brain natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) are useful biomarkers for diagnosis and prediction of prognosis. Both of these peptides are elevated in patients with chronic kidney disease (CKD), but there is no evidence as to which peptide is the more suitable biomarker in patients with severe renal dysfunction. METHODS AND
RESULTS: This retrospective cohort study evaluated patients with cardiovascular diseases (64.9±11.7 years, mean±SD). The end points were all-cause death and a composite end point of all-cause death, nonfatal myocardial infarction, nonfatal stroke, hospitalization for severe heart failure, and initiation of hemodialysis. Baseline plasma BNP and NT-proBNP levels, expressed as log-transformed data, were closely correlated in patients with CKD stages 1-3 (n=998) (r2=0.870, p<0.001), whereas for CKD stages 4-5 (n=85) there was a significant but weaker correlation (r2=0.209, p<0.001). During follow-up periods (51.3±0.4 months), 132 patients died and 202 patients reached the composite end point. The area under the receiver operating characteristic curve (AUROC) for BNP and NT-proBNP were similar for CKD stages 1-3. However, for CKD stages 4-5, the AUC for mortality for BNP was 0.713 and that for NT-proBNP was 0.760, while the AUC for the composite end point for BNP was 0.666 and that for NT-proBNP was 0.720.
CONCLUSIONS: Both BNP and NT-proBNP are useful biomarkers for mortality and cardiovascular events, but NT-proBNP may be superior to BNP for CKD stages 4-5.