B-type natriuretic peptide (BNP) and N-terminal pro-BNP in obese patients without heart failure: relationship to body mass index and gastric bypass surgery.
BACKGROUND
Further investigations are warranted to better characterize variables that may confound the clinical interpretation of plasma natriuretic peptide measurements, which are increasingly recognized to have diagnostic and predictive importance.


METHODS
Blood samples (EDTA plasma) from patients (n = 206) attending clinics for the medical treatment and follow-up of obesity were analyzed for B-type natriuretic peptide (BNP; Bayer assay) and the N-terminal segment of its prohormone (NT-proBNP; Roche assay). Natriuretic peptide concentration ranges were evaluated in those without diagnosis of congestive heart failure (CHF) or chronic kidney disease (CKD).


RESULTS
BNP and NT-proBNP were directly correlated (r = 0.87; P = 0.01), with NT-proBNP concentrations higher relative to BNP. Of obese patients without CHF or CKD, 21.6% (40 of 185) had NT-proBNP concentrations greater than the published assay upper reference limit. Concentrations of both natriuretic peptides were higher in patients currently exposed to beta blockers, patients with the diagnosis of hypertension or type 2 diabetes, and patients with a history of gastric bypass surgery. An inverse relationship between body mass index (BMI) and both BNP and NT-proBNP was evident. According to the National Institutes of Health, National Heart, Lung, and Blood Institute classification, more than 95% of the participants sampled in this study were either obesity class 2 (35 kg/m(2) < BMI < 39.9 kg/m(2)) or class 3 (BMI >or=40 kg/m(2))


CONCLUSIONS
A substantial proportion of obese patients without CHF or CKD have concentrations greater than the upper reference limit for NT-proBNP but not for simultaneously measured BNP. A history of gastric bypass surgery appeared to be a significant predictor of increased natriuretic peptide concentrations when assessed in a population of patients with class 2 or 3 obesity.
St Peter
John V
JV
College of Pharmacy and School of Medicine, University of Minnesota, Minneapolis, 55455-0343, USA. stpet003@umn.edu
Hartley
Guilford G
GG
Murakami
MaryAnn M
MM
Apple
Fred S
FS
D000328:Adult; D015992:Body Mass Index; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D015390:Gastric Bypass; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D007674:Kidney Diseases / Q000150:complications; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D009765:Obesity / Q000097:blood* / Q000150:complications / Q000601:surgery; D010446:Peptide Fragments / Q000097:blood*; D011446:Prospective Studies; D012016:Reference Values
D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain