title: Validation of a clinical prediction model for early admission to the intensive care unit of patients with pneumonia.
abstract: OBJECTIVE
  The Risk of Early Admission to the Intensive Care Unit (REA-ICU) index is a clinical prediction model that was derived based on 4,593 patients with community-acquired pneumonia (CAP) for predicting early admission to the intensive care unit (ICU; i.e., within 3 days following emergency department [ED] presentation). This study aimed to validate the REA-ICU index in an independent sample.
  
  
  METHODS
  The authors retrospectively stratified 850 CAP patients enrolled in a multicenter prospective randomized trial conducted in Switzerland, using the REA-ICU index, alternate clinical prediction models of severe pneumonia (SMART-COP, CURXO-80, and the 2007 IDSA/ATS minor severity criteria), and pneumonia severity assessment tools (the Pneumonia Severity Index [PSI] and CURB-65).
  
  
  RESULTS
  The rate of early ICU admission did not differ between the validation and derivation samples within each risk class of the REA-ICU index, ranging from 1.1% to 1.8% in risk class I to 27.1% to 27.6% in risk class IV. The areas under the receiver operating characteristic (ROC) curve were 0.76 (95% confidence interval [CI] = 0.70 to 0.83) and 0.80 (95% CI = 0.77 to 0.83) in the validation and derivation samples, respectively. In the validation sample, the REA-ICU index performed better than the pneumonia severity assessment tools, but failed to demonstrate an accuracy advantage over alternate prediction models in predicting ICU admission.
  
  
  CONCLUSIONS
  The REA-ICU index reliably stratifies CAP patients into four categories of increased risk for early ICU admission within 3 days following ED presentation. Further research is warranted to determine whether inflammatory biomarkers may improve the performance of this clinical prediction model.
authors.affiliation: Quality of Care Unit, Grenoble University Hospital, Grenoble, France. jlabarere@chu-grenoble.fr
authors.forename: José
authors.initials: J
authors.lastname: Labarère
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuetz
authors.forename: Bertrand
authors.initials: B
authors.lastname: Renaud
authors.forename: Yann-Erick
authors.initials: YE
authors.lastname: Claessens
authors.forename: Werner
authors.initials: W
authors.lastname: Albrich
authors.forename: Beat
authors.initials: B
authors.lastname: Mueller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D003422:Critical Care / Q000379:methods; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010343:Patient Admission; D011014:Pneumonia / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D011237:Predictive Value of Tests; D000091402:Prohibitins; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome