A decision model to compare health care costs of olanzapine and risperidone treatment for schizophrenia in Germany

Second-generation atypical antipsychotics such as clozapine, olanzapine, risperidone, quetiapine, ziprasidone, amisulpride and ariprazole offer the potential to reduce the significant health care resource demands in the treatment of schizophrenia through improved levels of initial clinical response and reduced levels of long-term acute relapse. However, the optimal sequencing of these drugs remains unclear. To consider this issue from a health economic viewpoint a decision model approach was used comparing healthcare costs and clinical outcomes when treating patients with alternative sequences of atypical antipsychotic treatment. Treated patients were assumed to be in a current acute episode with at least a 10-year history of disease and to be naive to previous atypical treatments. Treatment strategies were based on either first-line olanzapine or risperidone with switching to the alternative drug as second-line treatment following an inadequate clinical response to first-line drug therapy. Clinical response data were derived from a pivotal published comparative study of both olanzapine and risperidone. Published data on the long-term use of antipsychotic drugs where used wherever possible to populate the model for relapse rates during the maintenance phase. Health care resource data were defined for Germany based on expert clinical opinion. A treatment strategy of first-line olanzapine was shown to be cost saving over a 1-year period, with additional clinical benefits in the form of avoided relapses. The model suggests that over the first year of treatment a strategy of first-line olanzapine is associated with lower risk of additional relapse (0.33 fewer acute relapses per 100 patients per year) and with cost savings (€35,306 per 100 patients per year). There is a need for longer term direct in-trial comparisons of atypical antipsychotics to confirm these indicative results.