Pharmacoeconomic evaluations of atypical antipsychotics have become important elements in the decision making process. Decision tree models provide realistic, wide range projections of available data as well as important information on costs and outcomes.
This paper develops five different models, each of which becomes progressively more complex as key confounding variables are added.
Modelling studies indicated that atypical antipsychotics may be more or less cost-effective than typical antipsychotics depending upon whether or not key confounding variables such as switch, compliance, institutionalisation, dropout rate and disease severity were taken into account in the model’s ongoing development. Drawing from reviews of previously published models, the present study was undertaken to establish the extent to which various models included key confounding variables. The models studied were also appraised with the intention of learning from them and thereby enabling an evaluation of their strengths, weaknesses and effectiveness.
The assessment revealed that caution should be exercised when reviewing data as results indicate that serious discrepancies can occur between different methods of analysis. The authors argue in support of the need for standardised pharmacoeconomic models.