title: Circulating levels of pro-atrial natriuretic peptide in lower respiratory tract infections.
abstract: OBJECTIVE
  To analyse the mid region of plasma N-terminal pro-atrial natriuretic peptide (MR-proANP) levels in patients with lower respiratory tract infections to evaluate its prognostic use for the severity of disease and outcome.
  
  
  METHODS
  Prospective observational study. Setting. Emergency department of a university hospital.
  
  
  METHODS
  A total of 545 consecutive patients with lower respiratory tract infections and 50 healthy controls. Interventions. MR-proANP was measured in serum from all patients using a new sandwich immunoassay.
  
  
  RESULTS
  MR-proANP levels (median [IQR], in pmol L(-1)) were significantly higher in patients with lower respiratory tract infections when compared with controls (138.0 [74.1-279.0] vs. 72.7 [62.5-89.5], P < 0.001), with highest levels in patients with community-acquired pneumonia (CAP). MR-proANP, but not C-reactive protein (CRP) levels, gradually increased with increasing severity of CAP, classified according to the pneumonia severity index (PSI) score (P < 0.001). On admission, MR-proANP levels were significantly higher in nonsurvivors when compared with survivors (293.0 [154.0-633.0] vs. 129.0 [71.4-255.0], P < 0.001). In a receiver operating characteristic (ROC) analysis for the prediction of survival of patients with CAP the area under the ROC curve (AUC) for MR-proANP was 0.69, similar when compared with the PSI (AUC 0.74, P = 0.31), and better when compared with other biomarkers, i.e. procalcitonin (AUC 0.57, P = 0.08), CRP (AUC 0.52, P = 0.02), and leucocyte count (AUC 0.56, P = 0.07).
  
  
  CONCLUSIONS
  MR-proANP levels are increased in lower respiratory tract infections, especially in CAP. Together with other clinical, radiographic and laboratory findings, MR-proANP levels might be helpful for the risk stratification in CAP.
authors.affiliation: Department of Internal Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Müller
authors.forename: E
authors.initials: E
authors.lastname: Süess
authors.forename: P
authors.initials: P
authors.lastname: Schuetz
authors.forename: C
authors.initials: C
authors.lastname: Müller
authors.forename: R
authors.initials: R
authors.lastname: Bingisser
authors.forename: A
authors.initials: A
authors.lastname: Bergmann
authors.forename: D
authors.initials: D
authors.lastname: Stolz
authors.forename: M
authors.initials: M
authors.lastname: Tamm
authors.forename: N G
authors.initials: NG
authors.lastname: Morgenthaler
authors.forename: M
authors.initials: M
authors.lastname: Christ-Crain
mesh_terms: D000208:Acute Disease; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001991:Bronchitis / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D002908:Chronic Disease; D017714:Community-Acquired Infections / Q000097:blood / Q000401:mortality; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D011014:Pneumonia / Q000097:blood / Q000401:mortality; D011379:Prognosis; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000401:mortality; D012372:ROC Curve; D012141:Respiratory Tract Infections / Q000097:blood* / Q000401:mortality; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D009320:Atrial Natriuretic Factor; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide