RODOS Investigator Group - Risperidone Olanzapine Drug Outcomes studies in Schizophrenia (RODOS): health economic results of an international naturalistic study

We report the health economic data from the Risperidone Olanzapine Drug Outcomes studies in Schizophrenia (RODOS) programme. Details of the efficacy and tolerability data from RODOS are available in a companion paper. The population analysed during RODOS consisted of 1901 patients with diagnoses of schizophrenia or schizoaffective disorder. The mean ± SD daily dose of olanzapine treatment was 14.5 ± 5.1 mg compared to 5.3 ± 2.6 mg for risperidone. Use of concomitant neuroleptics (risperidone, 65%; olanzapine, 62%; P = 0.2) and other concomitant drugs (risperidone, 76%; olanzapine, 73%; P = 0.2) was similar in both groups. The mean ± SD total costs of all inpatient drugs was significantly (P < 0.001) higher for olanzapine (US$297.5 ± 305.1) than risperidone (US$159.9 ± 183.3). Although this difference in the average total costs in part reflects the longer treatment duration for olanzapine compared to risperidone (34 days versus 31 days), the cost difference remained when looking at costs on a daily basis. The mean ± SD daily cost of all inpatient drugs was also significantly (P < 0.001) higher for olanzapine (US$7.7 ± 4.0) than for risperidone (US$4.6 ± 2.9). These findings were very consistent across all nine countries. The results from RODOS suggest that treatment costs are significantly higher with olanzapine than with risperidone without any clinical benefit to offset this.