title: Biomarkers improve mortality prediction by prognostic scales in community-acquired pneumonia.
abstract: BACKGROUND
  Prognostic scales provide a useful tool to predict mortality in community-acquired pneumonia (CAP). However, the inflammatory response of the host, crucial in resolution and outcome, is not included in the prognostic scales.
  
  
  METHODS
  The aim of this study was to investigate whether information about the initial inflammatory cytokine profile and markers increases the accuracy of prognostic scales to predict 30-day mortality. To this aim, a prospective cohort study in two tertiary care hospitals was designed. Procalcitonin (PCT), C-reactive protein (CRP) and the systemic cytokines tumour necrosis factor alpha (TNFalpha) and interleukins IL6, IL8 and IL10 were measured at admission. Initial severity was assessed by PSI (Pneumonia Severity Index), CURB65 (Confusion, Urea nitrogen, Respiratory rate, Blood pressure, > or = 65 years of age) and CRB65 (Confusion, Respiratory rate, Blood pressure, > or = 65 years of age) scales. A total of 453 hospitalised CAP patients were included.
  
  
  RESULTS
  The 36 patients who died (7.8%) had significantly increased levels of IL6, IL8, PCT and CRP. In regression logistic analyses, high levels of CRP and IL6 showed an independent predictive value for predicting 30-day mortality, after adjustment for prognostic scales. Adding CRP to PSI significantly increased the area under the receiver operating characteristic curve (AUC) from 0.80 to 0.85, that of CURB65 from 0.82 to 0.85 and that of CRB65 from 0.79 to 0.85. Adding IL6 or PCT values to CRP did not significantly increase the AUC of any scale. When using two scales (PSI and CURB65/CRB65) and CRP simultaneously the AUC was 0.88.
  
  
  CONCLUSIONS
  Adding CRP levels to PSI, CURB65 and CRB65 scales improves the 30-day mortality prediction. The highest predictive value is reached with a combination of two scales and CRP. Further validation of that improvement is needed.
authors.affiliation: Servicio de Neumología, Universitary Hospital La Fe, Ciber de enfermedades respiratorias (CIBERES), Avda de Campanar 21, 46009 Valencia, Spain. rmenend@separ.es
authors.forename: R
authors.initials: R
authors.lastname: Menéndez
authors.forename: R
authors.initials: R
authors.lastname: Martínez
authors.forename: S
authors.initials: S
authors.lastname: Reyes
authors.forename: J
authors.initials: J
authors.lastname: Mensa
authors.forename: X
authors.initials: X
authors.lastname: Filella
authors.forename: M A
authors.initials: MA
authors.lastname: Marcos
authors.forename: A
authors.initials: A
authors.lastname: Martínez
authors.forename: C
authors.initials: C
authors.lastname: Esquinas
authors.forename: P
authors.initials: P
authors.lastname: Ramirez
authors.forename: A
authors.initials: A
authors.lastname: Torres
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D017714:Community-Acquired Infections / Q000097:blood / Q000401:mortality; D016207:Cytokines / Q000097:blood; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000097:blood / Q000401:mortality*; D011379:Prognosis; D011498:Protein Precursors / Q000097:blood
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D016207:Cytokines; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide