title: Serum cortisol predicts death and critical disease independently of CRB-65 score in community-acquired pneumonia: a prospective observational cohort study.
abstract: BACKGROUND
  Several biomarkers and prognostic scores have been evaluated to predict prognosis in community-acquired pneumonia (CAP). Optimal risk stratification remains to be evaluated. The aim of this study was to evaluate serum cortisol as biomarker for the prediction of adverse outcomes independently of the CRB-65 score und inflammatory biomarkers in a large cohort of hospitalised patients with CAP.
  
  
  METHODS
  984 hospitalised CAP-patients were included. Serum cortisol was measured and its prognostic accuracy compared to the CRB-65 score, leucocyte count and C-reactive protein. Predefined endpoints were 30-day mortality and the combined endpoint critical pneumonia, defined as presence of death occurring during antibiotic treatment, mechanical ventilation, catecholamine treatment or ICU admission.
  
  
  RESULTS
  64 patients died (6.5%) and 85 developed critical pneumonia (8.6%). Cortisol levels were significantly elevated in both adverse outcomes (p < 0.001) and predicted mortality (AUC 0.70, cut-off 795 nmol/L) and critical pneumonia (AUC 0.71) independently of all other measured variables after logistic regression analysis (p = 0.005 and 0.001, respectively). Prognostic accuracy of CRB-65 was significantly improved by adding cortisol levels (combined AUC 0.81 for both endpoints). In Kaplan-Meier analysis, cortisol predicted survival within different CRB-65 strata (p = 0.003). In subgroup analyses, cortisol independently predicted critical pneumonia when compared to procalcitonin, the CURB65 score and minor criteria for severe pneumonia according to the 2007 ATS/IDSA-guideline.
  
  
  CONCLUSIONS
  Cortisol predicts mortality and critical disease in hospitalised CAP-patients independently of clinical scores and inflammatory biomarkers. It should be incorporated into trials assessing optimal combinations of clinical criteria and biomarkers to improve initial high risk prediction in CAP.
authors.affiliation: Division of Pulmonology, Medical Department 1, University Hospital Carl Gustav Carus, Fetscherstr. 74, 01307 Dresden, Germany. martin.kolditz@uniklinikum-dresden.de
authors.forename: Martin
authors.initials: M
authors.lastname: Kolditz
authors.forename: Gert
authors.initials: G
authors.lastname: Höffken
authors.forename: Peter
authors.initials: P
authors.lastname: Martus
authors.forename: Gernot
authors.initials: G
authors.lastname: Rohde
authors.forename: Hartwig
authors.initials: H
authors.lastname: Schütte
authors.forename: Robert
authors.initials: R
authors.lastname: Bals
authors.forename: Norbert
authors.initials: N
authors.lastname: Suttorp
authors.forename: Mathias W
authors.initials: MW
authors.lastname: Pletz
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000401:mortality*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000401:mortality*; D011379:Prognosis; D011446:Prospective Studies; D044967:Serum / Q000737:chemistry*; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein; D006854:Hydrocortisone