title: The CHD challenge: comparing four cost-effectiveness models.
abstract: OBJECTIVE
  To compare four UK models evaluating the cost-effectiveness of interventions in coronary heart disease (CHD), exploring the relative importance of structure and inputs in accounting for differences, and the scope for consensus on structure and data.
  
  
  METHODS
  We compared published cost-effectiveness results (incremental cost, quality-adjusted life year, and cost-effectiveness ratio) of three models conforming to the National Institute for Health and Clinical Excellence guidelines dealing with three interventions (statins, percutaneous coronary intervention, and clopidogrel) with a model developed in Southampton. Comparisons were made using three separate stages: 1) comparison of published results; 2) comparison of the results using the same data inputs wherever possible; and 3) an in-depth exploration of reasons for differences and the potential for consensus.
  
  
  RESULTS
  Although published results differed by up to 73% (for statins), standardization of inputs (stage 2) narrowed these gaps. Greater understanding of the reasons for differences was achieved, but a consensus on preferred values for all data inputs was not reached.
  
  
  CONCLUSIONS
  We found that published guidance on methods was important to reduce variation in important model inputs. Although the comparison of models did not lead to consensus for all model inputs, it provided a better understanding of the reasons for these differences, and enhanced the transparency and credibility of all models. Similar comparisons would be aided by fuller publication of models, perhaps through detailed web appendices.
authors.affiliation: Wessex Institute University of Southampton, Southampton, UK. dturner@soton.ac.uk
authors.forename: David
authors.initials: D
authors.lastname: Turner
authors.forename: James
authors.initials: J
authors.lastname: Raftery
authors.forename: Keith
authors.initials: K
authors.lastname: Cooper
authors.forename: Eleanor
authors.initials: E
authors.lastname: Fairbank
authors.forename: Stephen
authors.initials: S
authors.lastname: Palmer
authors.forename: Sue
authors.initials: S
authors.lastname: Ward
authors.forename: Roberta
authors.initials: R
authors.lastname: Ara
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000191:economics; D000077144:Clopidogrel; D003327:Coronary Disease / Q000191:economics* / Q000628:therapy*; D003362:Cost-Benefit Analysis / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000191:economics / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017059:Models, Econometric; D010975:Platelet Aggregation Inhibitors / Q000191:economics / Q000627:therapeutic use; D019057:Quality-Adjusted Life Years; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000191:economics / Q000627:therapeutic use; D006113:United Kingdom
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine