title: How should we diagnose suspected deep-vein thrombosis?
abstract: BACKGROUND
  Many different approaches are used to diagnose suspected deep-vein thrombosis (DVT), but there has been little formal comparison of strategies.
  
  
  OBJECTIVE
  To identify the most cost-effective strategy for the UK National Health Service (NHS).
  
  
  METHODS
  Systematic review, meta-analysis and cost-effectiveness analysis.
  
  
  METHODS
  We identified 18 strategies and estimated the diagnostic performance of constituent tests by systematic review and meta-analysis. Outcomes of testing and treatment were estimated from published data or by an expert panel. Costs were estimated from NHS reference costs and published data. We built a decision-analysis model to estimate, for each strategy, the overall accuracy, costs, and outcomes (valued as quality-adjusted life-years, QALYs), compared to a 'no testing, no treatment' alternative. Probabilistic analysis estimated the net benefit of each strategy at varying thresholds for willingness to pay for health gain.
  
  
  RESULTS
  At the thresholds for willingness to pay recommended by the National Institute for Clinical Excellence (20,000 pounds sterling-30,000 pounds sterling per QALY), the optimal strategy was to discharge patients with a low or intermediate Wells score and negative D-dimer, limiting ultrasound to those with a high score or positive D-dimer. Strategies using radiological testing for all patients were only cost-effective at 40,000 pound sterling per QALY or more.
  
  
  CONCLUSIONS
  The optimal strategy for DVT diagnosis is to use ultrasound selectively in patients with a high clinical risk or positive D-dimer. Radiological testing for all patients does not appear to be a cost-effective use of health service resources.
authors.affiliation: Medical Care Research Unit, University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA. s.goodacre@sheffield.ac.uk
authors.forename: S
authors.initials: S
authors.lastname: Goodacre
authors.forename: M
authors.initials: M
authors.lastname: Stevenson
authors.forename: A
authors.initials: A
authors.lastname: Wailoo
authors.forename: F
authors.initials: F
authors.lastname: Sampson
authors.forename: A J
authors.initials: AJ
authors.lastname: Sutton
authors.forename: S
authors.initials: S
authors.lastname: Thomas
mesh_terms: D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D003935:Diagnostic Techniques, Cardiovascular / Q000191:economics; D006801:Humans; D019057:Quality-Adjusted Life Years; D013222:State Medicine / Q000191:economics; D006113:United Kingdom; D020246:Venous Thrombosis / Q000175:diagnosis*