Impact of patient sample on costs of events in pharmacoeconomic models

Pharmacoeconomic guidelines have focused on improving the measurement of effectiveness, but have largely ignored the assessment of cost inputs. We explored differences in adverse event cost estimates derived from three different sources in a case study of selective COX2 NSAIDs. We found substantial differences in costs of adverse events across data sources. We also determined that treatment costs associated with adverse events differed substantially based upon inclusion/exclusion criteria. Health services researchers should be deliberate in the choice of adverse event treatment costs that are used in decision analytic models. Future guidelines should seek to delineate best practices for cost calculations.