title: Routine use of the Pneumonia Severity Index for guiding the site-of-treatment decision of patients with pneumonia in the emergency department: a multicenter, prospective, observational, controlled cohort study.
abstract: BACKGROUND
  Although the Pneumonia Severity Index (PSI) has been extensively validated, little is known of the impact of its routine use as an aid to site-of-treatment decisions for patients with pneumonia who present to emergency departments (EDs).
  
  
  METHODS
  A prospective, observational, controlled cohort study of patients with pneumonia was conducted in 8 EDs that used the PSI (PSI-user EDs) and 8 EDs that did not use the PSI (PSI-nonuser EDs) in France. The outcomes examined included the proportion of "low-risk" patients (PSI risk classes I-III) treated as outpatients, all-cause 28-day mortality, admission of inpatients to the intensive care unit, and subsequent hospitalization of outpatients.
  
  
  RESULTS
  Of the 925 patients enrolled in the study, 472 (51.0%) were treated at PSI-user EDs, and 453 (49.0%) were treated at PSI-nonuser EDs; 449 (48.5%) of all patients were considered to be at low risk. In PSI-user EDs, 92 (42.8%) of 215 patients at low risk were treated as outpatients, compared with 56 (23.9%) of 234 patients at low risk in PSI-nonuser EDs. The adjusted odds ratios for outpatient treatment were higher for patients in PSI risk classes I and II who were treated in PSI-user EDs, compared with PSI-nonuser EDs (adjusted odds ratio, 7.0 [95% confidence interval, 2.0-25.0] and 4.6 [95% confidence interval, 1.3-16.2], respectively), whereas the adjusted odds ratio did not differ by PSI-user status among patients in risk class III or among patients at high risk. After adjusting for pneumonia severity, mortality was lower in patients who were treated in PSI-user EDs; other safety outcomes did not differ between patients treated in PSI-user and PSI-nonuser EDs.
  
  
  CONCLUSIONS
  The routine use of the PSI was associated with a larger proportion of patients in PSI risk classes I and II who had pneumonia and who were treated in the outpatient environment without compromising their safety.
authors.affiliation: Department of Emergency Medicine, Centre Hospitalier Universtaire Henri Mondor, Créteil, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Renaud
authors.forename: Eva
authors.initials: E
authors.lastname: Coma
authors.forename: Jose
authors.initials: J
authors.lastname: Labarere
authors.forename: Jan
authors.initials: J
authors.lastname: Hayon
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Roy
authors.forename: Hélène
authors.initials: H
authors.lastname: Boureaux
authors.forename: Fabienne
authors.initials: F
authors.lastname: Moritz
authors.forename: Jean François
authors.initials: JF
authors.lastname: Cibien
authors.forename: Thomas
authors.initials: T
authors.lastname: Guérin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Carré
authors.forename: Armelle
authors.initials: A
authors.lastname: Lafontaine
authors.forename: Marie Pierre
authors.initials: MP
authors.lastname: Bertrand
authors.forename: Aline
authors.initials: A
authors.lastname: Santin
authors.forename: Christian
authors.initials: C
authors.lastname: Brun-Buisson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Fine
authors.forename: Eric
authors.initials: E
authors.lastname: Roupie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality / Q000503:physiopathology; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality / Q000503:physiopathology; D003657:Decision Making; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality / Q000503:physiopathology; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index