title: Risk factors for the development of acute lung injury in patients with infectious pneumonia.
abstract: BACKGROUND
  Although pneumonia has been identified as the single most common risk factor for acute lung injury (ALI), we have a limited knowledge as to why ALI develops in some patients with pneumonia and not in others. The objective of this study was to determine frequency, risk factors, and outcome of ALI in patients with infectious pneumonia.
  
  
  METHODS
  A retrospective cohort study of adult patients with microbiologically positive pneumonia, hospitalized at two Mayo Clinic Rochester hospitals between January 1, 2005, and December 31, 2007. In a subsequent nested case-control analysis, we evaluated the differences in prehospital and intrahospital exposures between patients with and without ALI/acute respiratory distress syndrome (ARDS) matched by specific pathogen, isolation site, gender, and closest age in a 1:1 manner.
  
  
  RESULTS
  The study included 596 patients; 365 (61.2%) were men. The median age was 65 (IQR, 53 to 75) years. In total, 171 patients (28.7%) were diagnosed with ALI. The occurrence of ALI was less frequent in bacterial (n = 99 of 412, 24%) compared with viral (n = 19 of 55, 35%), fungal (n = 39 of 95, 41%), and mixed isolates pneumonias (n = 14 of 34, 41%; P = 0.002). After adjusting for baseline severity of illness and comorbidities, patients in whom ALI developed had a markedly increased risk of hospital death (ORadj 9.7; 95% CI, 6.0 to 15.9). In a nested case-control study, presence of shock (OR, 8.9; 95% CI, 2.8 to 45.9), inappropriate initial antimicrobial treatment (OR, 3.2; 95% CI, 1.3 to 8.5), and transfusions (OR, 4.8; 95% CI, 1.5 to 19.6) independently predicted ALI development.
  
  
  CONCLUSIONS
  The development of ALI among patients hospitalized with infectious pneumonia varied among pulmonary pathogens and was associated with increased mortality. Inappropriate initial antimicrobial treatment and transfusion predict the development of ALI independent of pathogen.
authors.affiliation: The Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Marija
authors.initials: M
authors.lastname: Kojicic
authors.forename: Guangxi
authors.initials: G
authors.lastname: Li
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Hanson
authors.forename: Kun-Moo
authors.initials: KM
authors.lastname: Lee
authors.forename: Lokendra
authors.initials: L
authors.lastname: Thakur
authors.forename: Jayanth
authors.initials: J
authors.lastname: Vedre
authors.forename: Adil
authors.initials: A
authors.lastname: Ahmed
authors.forename: Larry M
authors.initials: LM
authors.lastname: Baddour
authors.forename: Jay H
authors.initials: JH
authors.lastname: Ryu
authors.forename: Ognjen
authors.initials: O
authors.lastname: Gajic
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000150:complications* / Q000382:microbiology / Q000628:therapy; D012128:Respiratory Distress Syndrome / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome