N-terminal proBNP--marker of cardiac dysfunction, fluid overload, or malnutrition in hemodialysis patients?
OBJECTIVE
N-terminal probrain type natriuretic peptide (NTproBNP) has been proven to be a valuable biomarker for predicting cardiac events and mortality in the hemodialysis population. However recent reports have suggested that NTproBNP is a marker of volume overload rather than one of cardiac dysfunction. Therefore this study investigated the effect of fluid volume status on NTproBNP.


METHODS
Volume status was determined pre- and postdialysis in 72 stable hemodialysis outpatients by multifrequency bioimpedance, and the relationship to NTproBNP values was examined.


RESULTS
The mean and median NTproBNP values were 931.9 +/- 230 and 242 (90 to 688) pmol/L, respectively. On simple correlation, NTproBNP was associated with markers of volume overload and cardiac dysfunction. However, on logistical regression analysis, the strongest association was with the predialysis ratio of extracellular water/total body water (beta 26.6, F29.6, P = 0.000), followed by postdialysis mean arterial blood pressure (beta 0.14, F17.1, P = 0.000), dialysate calcium concentration (beta -1.19, F14.1, P = 0.002), and change in extracellular fluid volume with dialysis (beta 0.27, F7.4, P = 0.009)


CONCLUSIONS
In this study, NTproBNP was not associated with cardiac dysfunction as assessed by transthoracic echo or nuclear medicine scintigraphy but was dependent on factors associated with volume overload. However, because bioimpedance results can also be affected by malnutrition with loss of cell mass, NTproBNP may be elevated not only in patients with volume overload, but also those with malnutrition.
Center for Nephrology, Royal Free Hospital, London, UK.
John
J
Booth
Jennifer
J
Pinney
Andrew
A
Davenport
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D001834:Body Water / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D017097:Electric Impedance; D005260:Female; D006331:Heart Diseases / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D044342:Malnutrition / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010045:Outpatients; D010446:Peptide Fragments / Q000097:blood*; D011379:Prognosis; D006435:Renal Dialysis / Q000009:adverse effects; D018570:Risk Assessment; D012307:Risk Factors; D015854:Up-Regulation; D014883:Water-Electrolyte Imbalance / Q000097:blood* / Q000209:etiology / Q000503:physiopathology
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D002118:Calcium