title: Cost-effectiveness of strategies for diagnosing pulmonary embolism among emergency department patients presenting with undifferentiated symptoms.
abstract: OBJECTIVE
  Symptoms associated with pulmonary embolism can be nonspecific and similar to many competing diagnoses, leading to excessive costly testing and treatment, as well as missed diagnoses. Objective studies are essential for diagnosis. This study evaluates the cost-effectiveness of different diagnostic strategies in an emergency department (ED) for patients presenting with undifferentiated symptoms suggestive of pulmonary embolism.
  
  
  METHODS
  Using a probabilistic decision model, we evaluated the incremental costs and effectiveness (quality-adjusted life-years gained) of 60 testing strategies for 5 patient pretest categories (distinguished by Wells score [high, moderate, or low] and whether deep venous thrombosis is clinically suspected). We performed deterministic and probabilistic sensitivity analyses.
  
  
  RESULTS
  In the base case, for all patient pretest categories, the most cost-effective diagnostic strategy is to use an initial enzyme-linked immunosorbent assay D-dimer test, followed by compression ultrasonography of the lower extremities if the D-dimer is above a specified cutoff. The level of the preferred cutoff varies with the Wells pretest category and whether a deep venous thrombosis is clinically suspected. D-dimer cutoffs higher than the current recommended cutoff were often preferred for patients with even moderate and high Wells categories. Compression ultrasonography accuracy had to decrease below commonly cited levels in the literature before it was not part of a preferred strategy.
  
  
  CONCLUSIONS
  When pulmonary embolism is suspected in the ED, use of an enzyme-linked immunosorbent assay D-dimer assay, often at cutoffs higher than those currently in use (for patients in whom deep venous thrombosis is not clinically suspected), followed by compression ultrasonography as appropriate, can reduce costs and improve outcomes.
authors.affiliation: Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA. ram1@stanford.edu
authors.forename: Ram S
authors.initials: RS
authors.lastname: Duriseti
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Brandeau
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis; D000784:Aortic Dissection / Q000175:diagnosis; D001014:Aortic Aneurysm / Q000175:diagnosis; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000191:economics; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000592:standards; D006801:Humans; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000191:economics; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000000981:diagnostic imaging