title: Stability in community-acquired pneumonia: one step forward with markers?
abstract: BACKGROUND
  Biological markers as an expression of systemic inflammation have been recognised as useful for evaluating the host response in community-acquired pneumonia (CAP). The objective of this study was to evaluate whether the biological markers procalcitonin (PCT) and C-reactive protein (CRP) might reflect stability after 72 h of treatment and the absence of subsequent severe complications.
  
  
  METHODS
  A prospective cohort study was performed in 394 hospitalised patients with CAP. Clinical stability was evaluated using modified Halm's criteria: temperature <or=37.2 degrees C; heart rate <or=100 beats/min; respiratory rate <or=24 breaths/min; systolic blood pressure >or=90 mm Hg; oxygen saturation >or=90%; or arterial oxygen tension >or=60 mm Hg. PCT and CRP levels were measured on day 1 and after 72 h. Severe complications were defined as mechanical ventilation, shock and/or intensive care unit (ICU) admission, or death after 72 h of treatment.
  
  
  RESULTS
  220 patients achieved clinical stability at 72 h and had significantly lower levels of CRP (4.2 vs 7 mg/dl) and of PCT (0.33 vs 0.48 ng/ml). Regression logistic analyses were performed to calculate several areas under the ROC curve (AUC) to predict severe complications. The AUC for clinical stability was 0.77, 0.84 when CRP was added (p = 0.059) and 0.77 when PCT was added (p = 0.45). When clinical stability was achieved within 72 h and marker levels were below the cut-off points (0.25 ng/ml for PCT and 3 mg/dl for CRP), no severe complications occurred.
  
  
  CONCLUSIONS
  Low levels of CRP and PCT at 72 h in addition to clinical criteria might improve the prediction of absence of severe complications.
authors.affiliation: Servicio de Neumología, Universitary Hospital La Fe, Ciber de enfermedades respiratorias (CIBERES), Valencia, Spain. rmenend@separ.es
authors.forename: R
authors.initials: R
authors.lastname: Menéndez
authors.forename: R
authors.initials: R
authors.lastname: Martinez
authors.forename: S
authors.initials: S
authors.lastname: Reyes
authors.forename: J
authors.initials: J
authors.lastname: Mensa
authors.forename: E
authors.initials: E
authors.lastname: Polverino
authors.forename: X
authors.initials: X
authors.lastname: Filella
authors.forename: C
authors.initials: C
authors.lastname: Esquinas
authors.forename: A
authors.initials: A
authors.lastname: Martinez
authors.forename: P
authors.initials: P
authors.lastname: Ramirez
authors.forename: A
authors.initials: A
authors.lastname: Torres
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism*; D002116:Calcitonin / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide; D017714:Community-Acquired Infections / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; C000606589:CALCA protein, human; D016207:Cytokines; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide