title: Clinical and economic consequences of ventilator-associated pneumonia: a systematic review.
abstract: BACKGROUND
  Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in critically ill patients. The clinical and economic consequences of VAP are unclear, with a broad range of values reported in the literature
  
  
  OBJECTIVE
  To perform a systematic review to determine the incidence of VAP and its attributable mortality rate, length of stay, and costs.
  
  
  METHODS
  Computerized PUBMED and MEDLINE search supplemented by manual searches for relevant articles, limited to articles published after 1990.
  
  
  METHODS
  English-language observational studies and randomized trials that provided data on the incidence of VAP were included. Matched cohort studies were included for calculation of attributable mortality rate and length of stay.
  
  
  METHODS
  Data were extracted on patient population, diagnostic criteria for VAP, incidence, outcome, type of intensive care unit, and study design.
  
  
  RESULTS
  The cumulative incidence of VAP was calculated by combining the results of several studies using standard formulas for combining proportions, in which the weighted average and variance are calculated. Results from studies comparing intensive care unit and hospital mortality due to VAP, additional length of stay, and additional days of mechanical ventilation were pooled using a random effects model, with assessment of heterogeneity.
  
  
  RESULTS
  Our findings indicate a) between 10% and 20% of patients receiving >48 hrs of mechanical ventilation will develop VAP; b) critically ill patients who develop VAP appear to be twice as likely to die compared with similar patients without VAP (pooled odds ratio, 2.03; 95% confidence interval, 1.16-3.56); c) patients with VAP have significantly longer intensive care unit lengths of stay (mean = 6.10 days; 95% confidence interval, 5.32-6.87 days); and d) patients who develop VAP incur > or = USD $10,019 in additional hospital costs.
  
  
  CONCLUSIONS
  Ventilator-associated pneumonia occurs in a considerable proportion of patients undergoing mechanical ventilation and is associated with substantial morbidity, a two-fold mortality rate, and excess cost. Given these findings, strategies that effectively prevent VAP are urgently needed.
authors.affiliation: Section of Infectious Diseases, Department of Medicine, University of Wisconsin Medical School, 600 Highland Avenue, Madison, WI 53792, USA. ns2@medicine.wisc.edu
authors.forename: Nasia
authors.initials: N
authors.lastname: Safdar
authors.forename: Cameron
authors.initials: C
authors.lastname: Dezfulian
authors.forename: Harold R
authors.initials: HR
authors.lastname: Collard
authors.forename: Sanjay
authors.initials: S
authors.lastname: Saint
mesh_terms: D003422:Critical Care / Q000191:economics*; D003428:Cross Infection / Q000191:economics* / Q000209:etiology / Q000401:mortality; D017048:Health Care Costs; D006801:Humans; D015994:Incidence; D007902:Length of Stay / Q000191:economics; D011014:Pneumonia / Q000191:economics* / Q000209:etiology / Q000401:mortality; D012121:Respiration, Artificial / Q000009:adverse effects*