title: Biomarkers of cardiac dysfunction and mortality from community-acquired pneumonia in adults.
abstract: BACKGROUND
  Cardiac dysfunction is common in acute respiratory diseases and may influence prognosis. We hypothesised that blood levels of N-terminal B-type natriuretic peptide (NT-proBNP) and high-sensitivity Troponin T would predict mortality in adults with community-acquired pneumonia.
  
  
  RESULTS
  A prospective cohort of 474 consecutive patients admitted with community-acquired pneumonia to two New Zealand hospitals over one year. Blood taken on admission was available for 453 patients and was analysed for NT-proBNP and Troponin T. Elevated levels of NT-proBNP (>220 pmol/L) were present in 148 (33%) and 86 (19%) of these patients respectively. Among the 26 patients who died within 30 days of admission, 23 (89%) had a raised NT-proBNP and 14 (53%) had a raised Troponin T level on admission compared to 125 (29%) and 72 (17%) of the 427 who survived (p values<0.001). Both NT-proBNP and Troponin T predicted 30-day mortality in age-adjusted analysis but after mutual adjustment for the other cardiac biomarker and the Pneumonia Severity Index, a raised N-terminal pro-brain natriuretic peptide remained a predictor of 30-day mortality (OR = 5.3, 95% CI 1.4-19.8, p = 0.013) but Troponin T did not (OR = 1.3, 95% CI 0.5-3.2, p = 0.630). The areas under the receiver-operating curves to predict 30-day mortality were similar for NT-proBNP (0.88) and the Pneumonia Severity Index (0.87).
  
  
  CONCLUSIONS
  Elevated N-terminal B-type natriuretic peptide is a strong predictor of mortality from community-acquired pneumonia independent of clinical prognostic indicators. The pathophysiological basis for this is unknown but suggests that cardiac involvement may be an under-recognised determinant of outcome in pneumonia and may require a different approach to treatment. In the meantime, measurement of B-type natriuretic peptides may help to assess prognosis.
authors.affiliation: Department of Respiratory Medicine, Waikato Hospital, Hamilton, New Zealand.
authors.forename: Catherina L
authors.initials: CL
authors.lastname: Chang
authors.forename: Graham D
authors.initials: GD
authors.lastname: Mills
authors.forename: Noel C
authors.initials: NC
authors.lastname: Karalus
authors.forename: Lance C
authors.initials: LC
authors.lastname: Jennings
authors.forename: Richard
authors.initials: R
authors.lastname: Laing
authors.forename: David R
authors.initials: DR
authors.lastname: Murdoch
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chambers
authors.forename: Dominic
authors.initials: D
authors.lastname: Vettise
authors.forename: Christine M
authors.initials: CM
authors.lastname: Tuffery
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hancox
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000097:blood / Q000401:mortality* / Q000503:physiopathology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011014:Pneumonia / Q000097:blood / Q000401:mortality* / Q000503:physiopathology*; D012372:ROC Curve; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D020107:Troponin T; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain