B-type natriuretic peptide and renal function in the diagnosis of heart failure: an analysis from the Breathing Not Properly Multinational Study.
BACKGROUND
Both B-type natriuretic peptide (BNP) and renal function are prognostic indicators of survival in patients with congestive heart failure (CHF). However, relationships between BNP, renal function, and heart failure as an emergency diagnosis are unknown.


METHODS
The Breathing Not Properly Multinational Study was a prospectively designed diagnostic test evaluation study conducted in seven centers. Of 1,586 participants who presented with acute dyspnea, 1,452 patients (91.6%) had both BNP level and baseline estimated glomerular filtration rate (eGFR) available. Patients with an eGFR less than 15 mL/min/1.73 m2 and those on dialysis therapy were excluded. The final diagnosis was adjudicated by two independent cardiologists who were blinded to BNP results.


RESULTS
The final diagnosis was CHF in 715 patients (49.2%). Raw and log-log transformed correlations between BNP and eGFR values were r = -0.19 and r = -0.17 for those with CHF and r = -0.20 and r = -0.31 for those without CHF (both P < 0.0001 for r not equal 0). Mean BNP levels were 561.6 pg/mL (162.3 fmol/mL), 647.5 pg/mL (187.1 fmol/mL), 745.6 pg/mL (215.5 fmol/mL), and 850.7 pg/mL (245.8 fmol/mL) for those with CHF and 85.4 pg/mL (24.7 fmol/mL), 131.7 pg/mL (38.1 fmol/mL), 297.2 pg/mL (85.9 fmol/mL), and 285.0 pg/mL (82.3 fmol/mL) for those without CHF in eGFR categories of 90 or greater, 89 to 60, 59 to 30, and less than 30 mL/min/1.73 m2, respectively. The area under the receiver operating characteristic curve and optimum cut points for BNP were 0.91 and 70.7 pg/mL (20.4 fmol/mL), 0.90 and 104.3 pg/mL (30.1 fmol/mL), 0.81 and 201.2 pg/mL (58.1 fmol/mL), and 0.86 and 225.0 pg/mL (65.0 fmol/mL) for the eGFR categories of 90 or greater, 89 to 60, 59 to 30, and less than 30 mL/min/1.73 m2, respectively.


CONCLUSIONS
Renal function correlates weakly with BNP and influences the optimal cut point for BNP, particularly in those with an eGFR less than 60 mL/min/1.73 m2.
McCullough
Peter A
PA
University of California, San Diego Veteran's Affairs Medical Center, San Diego, CA, USA. pmc975@yahoo.com
Duc
Philippe
P
Omland
Torbjørn
T
McCord
James
J
Nowak
Richard M
RM
Hollander
Judd E
JE
Herrmann
Howard C
HC
Steg
Philippe G
PG
Westheim
Arne
A
Knudsen
Cathrine Wold
CW
Storrow
Alan B
AB
Abraham
William T
WT
Lamba
Sumant
S
Wu
Alan H B
AH
Perez
Alberto
A
Clopton
Paul
P
Krishnaswamy
Padma
P
Kazanegra
Radmila
R
Maisel
Alan S
AS
D000208:Acute Disease; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood*; D015331:Cohort Studies; D004417:Dyspnea / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012015:Reference Standards; D013534:Survival
D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor