A link between impaired lung function and increased cardiac stress

Respiration. 2010;79(5):355-62. doi: 10.1159/000265751. Epub 2009 Dec 10.


Background: Patients with impaired lung function often have systemic inflammation. C-reactive protein (CRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are markers for inflammation and cardiac stress, respectively.

Objectives: To evaluate the association between both markers and the potential impacts of lung disease on this relationship.

Methods: CRP and NT-proBNP were prospectively measured in 697 consecutive outpatients (57.5 +/- 16.4 years) with chronic dyspnea. The patients were stratified into quartiles according to CRP levels (quartile 1: median CRP 0.35 mg/l; quartile 2: 1.50 mg/l; quartile 3: 3.62 mg/l; quartile 4: 10.90 mg/l) and classified into 2 categories based on the presence (n = 176) or absence (n = 521) of heart disease.

Results: Patients with at least moderately severe airway obstruction and those with interstitial lung disease had higher CRP values than patients without lung disease (median 3.50 vs. 4.34 vs. 1.80 mg/l, respectively; p < 0.01). In patients without heart disease, NT-proBNP values increased from CRP quartiles 1-3 to quartile 4 (median 47.4 vs. 82.1 pg/ml; p < 0.01) after adjusting for important covariates such as age, sex, body mass index, renal function and arterial hypertension. Likewise, the values for NT-proBNP were lower in CRP quartiles 1-3 than in quartile 4 (median 212.0 vs. 647.7 pg/ml; p < 0.01) in patients with heart disease after additional adjustment for the type of cardiac disorder. Lung disease had no direct effect on the relationship between CRP and NT-proBNP.

Conclusion: Systemic inflammation that originates in the lung places an excess burden on the heart, which may contribute to the functional impairment of patients with advanced pulmonary disease.

MeSH terms

  • Airway Obstruction / etiology
  • Biomarkers / blood
  • C-Reactive Protein / analysis*
  • Dyspnea / etiology
  • Female
  • Forced Expiratory Volume
  • Heart Diseases / blood*
  • Humans
  • Lung Diseases / blood*
  • Male
  • Middle Aged
  • Natriuretic Peptide, Brain / blood*
  • Peptide Fragments / blood*
  • Prospective Studies
  • Severity of Illness Index


  • Biomarkers
  • Peptide Fragments
  • pro-brain natriuretic peptide (1-76)
  • Natriuretic Peptide, Brain
  • C-Reactive Protein