title: Atrial fibrillation is an independent determinant of increased NT-proBNP levels in outpatients with signs and symptoms of heart failure.
abstract: BACKGROUND
  N-terminal pro-B-type natriuretic peptide (NT-proBNP) is increasingly used in the diagnosis and prognostic assessment of heart failure; however, the possible influence of atrial fibrillation on BNP is still a matter of controversy. We assessed the influence of atrial fibrillation on NT-proBNP levels in outpatients with signs and symptoms of heart failure.
  
  
  METHODS
  Consecutive outpatients (n = 306) referred to a university hospital heart-failure clinic for evaluation of signs and symptoms of heart failure underwent clinical and echocardiographic assessment and had their NT-proBNP levels determined in a sandwich chemiluminescent immunoassay with two antibodies on an Elecsys analyzer. The influence of atrial fibrillation on NT-proBNP levels was assessed using a non-parsimonious linear regression model with propensity score adjustments to balance for possible confounders.
  
  
  RESULTS
  Atrial fibrillation was associated with increased NT-proBNP levels in patients with (median concentration 1944 vs. 1390 pg/ml) and without (1093 vs. 172 pg/ml) underlying structural disease (P < 0.001). In a linear regression model with a propensity score, atrial fibrillation emerged as an independent determinant of NT-proBNP levels (P = 0.023), even after allowing for possible confounders (left ventricular ejection fraction and end-diastolic diameter, left atrial diameter, mitral insufficiency, age, sex, NYHA class or heart rate).
  
  
  CONCLUSIONS
  Atrial fibrillation is an independent determinant of increased NT-proBNP levels. This association should be taken into account when NT-proBNP levels are used in the diagnosis of heart failure in patients with atrial fibrillation.
authors.affiliation: Department of Vascular Diseases, Division of Internal Medicine, University Clinical Center, Ljubljana, Slovenia. borut.jug@gmail.com
authors.forename: Borut
authors.initials: B
authors.lastname: Jug
authors.forename: Miran
authors.initials: M
authors.lastname: Sebestjen
authors.forename: Miso
authors.initials: M
authors.lastname: Sabovic
authors.forename: Maja
authors.initials: M
authors.lastname: Pohar
authors.forename: Irena
authors.initials: I
authors.lastname: Keber
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D015897:Comorbidity; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010045:Outpatients / Q000706:statistics & numerical data; D010446:Peptide Fragments / Q000097:blood*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D017524:Slovenia / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain