title: A simple clinical predictive index for objective estimates of mortality in acute lung injury.
abstract: OBJECTIVE
  We sought to develop a simple point score that would accurately capture the risk of hospital death for patients with acute lung injury (ALI).
  
  
  METHODS
  This is a secondary analysis of data from two randomized trials. Baseline clinical variables collected within 24 hours of enrollment were modeled as predictors of hospital mortality using logistic regression and bootstrap resampling to arrive at a parsimonious model. We constructed a point score based on regression coefficients.
  
  
  METHODS
  Medical centers participating in the Acute Respiratory Distress Syndrome Clinical Trials Network (ARDSnet).
  
  
  METHODS
  Model development: 414 patients with nontraumatic ALI participating in the low tidal volume arm of the ARDSnet Acute Respiratory Management in ARDS study. Model validation: 459 patients participating in the ARDSnet Assessment of Low tidal Volume and elevated End-expiratory volume to Obviate Lung Injury study. Model Validation: 459 patients participating in the ARDSnet Assessment of Low tidal Volume and elevated End-expiratory volume to Obviate Lung Injury trial.
  
  
  METHODS
  None.
  
  
  RESULTS
  Variables comprising the prognostic model were hematocrit <26% (1 point), bilirubin >or=2 mg/dL (1 point), fluid balance >2.5 L positive (1 point), and age (1 point for age 40-64 years, 2 points for age >or=65 years). Predicted mortality (95% confidence interval) for 0, 1, 2, 3, and 4+ point totals was 8% (5% to 14%), 17% (12% to 23%), 31% (26% to 37%), 51% (43% to 58%), and 70% (58% to 80%), respectively. There was an excellent agreement between predicted and observed mortality in the validation cohort. Observed mortality for 0, 1, 2, 3, and 4+ point totals in the validation cohort was 12%, 16%, 28%, 47%, and 67%, respectively. Compared with the Acute Physiology Assessment and Chronic Health Evaluation III score, areas under the receiver operating characteristic curve for the point score were greater in the development cohort (0.72 vs. 0.67, p = 0.09) and lower in the validation cohort (0.68 vs. 0.75, p = 0.03).
  
  
  CONCLUSIONS
  Mortality in patients with ALI can be predicted using an index of four readily available clinical variables with good calibration. This index may help inform prognostic discussions, but validation in nonclinical trial populations is necessary before widespread use.
authors.affiliation: Division of Pulmonary and Critical Care Medicine , University of Washington, Seattle, WA, USA. crcooke@u.washington.edu
authors.forename: Colin R
authors.initials: CR
authors.lastname: Cooke
authors.forename: Chirag V
authors.initials: CV
authors.lastname: Shah
authors.forename: Robert
authors.initials: R
authors.lastname: Gallop
authors.forename: Scarlett
authors.initials: S
authors.lastname: Bellamy
authors.forename: Marek
authors.initials: M
authors.lastname: Ancukiewicz
authors.forename: Mark D
authors.initials: MD
authors.lastname: Eisner
authors.forename: Paul N
authors.initials: PN
authors.lastname: Lanken
authors.forename: A Russell
authors.initials: AR
authors.lastname: Localio
authors.forename: Jason D
authors.initials: JD
authors.lastname: Christie
mesh_terms: D018806:APACHE; D055371:Acute Lung Injury / Q000401:mortality*; D000328:Adult; D000368:Aged; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis