title: Influence of age on the cost-effectiveness of diagnostic strategies for suspected pulmonary embolism.
abstract: BACKGROUND
  Age has a marked effect on the diagnostic yield of D-dimer measurement and lower limb compression ultrasonography (CUS) in patients with suspected pulmonary embolism (PE), suggesting that specific diagnostic strategies may be needed in elderly patients.
  
  
  OBJECTIVE
  To evaluate the cost-effectiveness of including D-dimer and CUS in the workup of PE, with particular attention to patient age.
  
  
  METHODS
  We analyzed data from two recent outcome studies that enrolled 1721 consecutive outpatients with suspected PE. Both studies used a sequential diagnostic strategy that included assessment of clinical probability, D-dimer measurement, CUS, and helical computed tomography (hCT). A decision analysis model was created for analyzing cost-effectiveness according to six classes of age. The main outcome measures were 3-month quality-adjusted expected survival and costs per patient managed.
  
  
  RESULTS
  All strategies were equally safe, with variations in the 3-month survival never exceeding 0.5% as compared to the most effective strategy. D-dimer measurement was highly cost-saving under the age of 80 years. Above 80 years, the cost-sparing effect of D-dimer was diminished, but not completely abolished. Inclusion of CUS increased the costs of diagnostic strategies irrespective of age. Results were unchanged over a wide range of the variables of interest (costs, sensitivity, and specificity of the tests).
  
  
  CONCLUSIONS
  Diagnostic strategies using D-dimer are less expensive. The cost-sparing effect of D-dimer is reduced but not abolished above 80 years, suggesting that adapting specific diagnostic strategies in elderly outpatients is not mandatory. CUS is costly, and only marginally improves the safety of diagnostic strategies for PE.
authors.affiliation: Division of Angiology and Haemostasis, Department of Internal Medicine, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland. marc.righini@hcuge.ch
authors.forename: M
authors.initials: M
authors.lastname: Righini
authors.forename: M
authors.initials: M
authors.lastname: Nendaz
authors.forename: G
authors.initials: G
authors.lastname: Le Gal
authors.forename: H
authors.initials: H
authors.lastname: Bounameaux
authors.forename: A
authors.initials: A
authors.lastname: Perrier
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D003362:Cost-Benefit Analysis; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D006801:Humans; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000188:drug therapy; D012680:Sensitivity and Specificity
chemical_list: D000925:Anticoagulants; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D