title: Derivation and validation of a prognostic model for pulmonary embolism.
abstract: BACKGROUND
  An objective and simple prognostic model for patients with pulmonary embolism could be helpful in guiding initial intensity of treatment.
  
  
  OBJECTIVE
  To develop a clinical prediction rule that accurately classifies patients with pulmonary embolism into categories of increasing risk of mortality and other adverse medical outcomes.
  
  
  METHODS
  We randomly allocated 15,531 inpatient discharges with pulmonary embolism from 186 Pennsylvania hospitals to derivation (67%) and internal validation (33%) samples. We derived our prediction rule using logistic regression with 30-day mortality as the primary outcome, and patient demographic and clinical data routinely available at presentation as potential predictor variables. We externally validated the rule in 221 inpatients with pulmonary embolism from Switzerland and France.
  
  
  METHODS
  We compared mortality and nonfatal adverse medical outcomes across the derivation and two validation samples.
  
  
  RESULTS
  The prediction rule is based on 11 simple patient characteristics that were independently associated with mortality and stratifies patients with pulmonary embolism into five severity classes, with 30-day mortality rates of 0-1.6% in class I, 1.7-3.5% in class II, 3.2-7.1% in class III, 4.0-11.4% in class IV, and 10.0-24.5% in class V across the derivation and validation samples. Inpatient death and nonfatal complications were <or= 1.1% among patients in class I and <or= 1.9% among patients in class II.
  
  
  CONCLUSIONS
  Our rule accurately classifies patients with pulmonary embolism into classes of increasing risk of mortality and other adverse medical outcomes. Further validation of the rule is important before its implementation as a decision aid to guide the initial management of patients with pulmonary embolism.
authors: Division of General Internal Medicine, Clinical Epidemiology Center, University of Lausanne, Lausanne, Switzerland. drahomir.aujesky@chuv.ch
authors: Drahomir
authors: D
authors: Aujesky
authors: D Scott
authors: DS
authors: Obrosky
authors: Roslyn A
authors: RA
authors: Stone
authors: Thomas E
authors: TE
authors: Auble
authors: Arnaud
authors: A
authors: Perrier
authors: Jacques
authors: J
authors: Cornuz
authors: Pierre-Marie
authors: PM
authors: Roy
authors: Michael J
authors: MJ
authors: Fine
mesh_terms: D000208:Acute Disease; D000368:Aged; D002423:Cause of Death; D015897:Comorbidity; D003661:Decision Support Techniques; D016002:Discriminant Analysis; D005260:Female; D005602:France / Q000453:epidemiology; D006785:Hospitals, University; D006801:Humans; D016015:Logistic Models; D008297:Male; D010414:Pennsylvania / Q000453:epidemiology; D011237:Predictive Value of Tests; D011379:Prognosis; D011655:Pulmonary Embolism / Q000145:classification* / Q000150:complications / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D012372:ROC Curve; D018570:Risk Assessment / Q000458:organization & administration*; D012307:Risk Factors; D012720:Severity of Illness Index; D013557:Switzerland / Q000453:epidemiology