Circulating levels of pro-atrial natriuretic peptide in lower respiratory tract infections

J Intern Med. 2006 Dec;260(6):568-76. doi: 10.1111/j.1365-2796.2006.01722.x.


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.

Design: Prospective observational study. Setting. Emergency department of a university hospital.

Subjects: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Aged
  • Atrial Natriuretic Factor / blood*
  • Biomarkers / blood
  • Bronchitis / blood
  • C-Reactive Protein / analysis
  • Calcitonin / blood
  • Calcitonin Gene-Related Peptide
  • Chronic Disease
  • Community-Acquired Infections / blood
  • Community-Acquired Infections / mortality
  • Female
  • Humans
  • Leukocyte Count
  • Male
  • Pneumonia / blood
  • Pneumonia / mortality
  • Prognosis
  • Prospective Studies
  • Protein Precursors / blood
  • Pulmonary Disease, Chronic Obstructive / blood
  • Pulmonary Disease, Chronic Obstructive / mortality
  • ROC Curve
  • Respiratory Tract Infections / blood*
  • Respiratory Tract Infections / mortality
  • Severity of Illness Index


  • Biomarkers
  • CALCA protein, human
  • Protein Precursors
  • Atrial Natriuretic Factor
  • Calcitonin
  • C-Reactive Protein
  • Calcitonin Gene-Related Peptide