Risperidone compared with olanzapine in a naturalistic clinical study in Ireland: a cost analysis

Risperidone and olanzapine are thought to have similar clinical effects. This study was designed to compare costs of treatment.

To compare costs of treatment with risperidone or olanzapine in a naturalistic setting.

The Irish Risperidone Olanzapine Drug Outcomes studies in Schizophrenia (RODOS) programme was a retrospective review of medical notes and prescription charts in 396 inpatients with schizophrenia or schizoaffective disorder. The main outcome measure was cost of inpatient drug treatment.

There was no statistical difference in length of hospital stay between risperidone-treated and olanzapine-treated patients (mean duration of stay 37.8 and 40.5 days, p=0.90). Mean+/-SD doses of risperidone and olanzapine were 4.2+/-2.1 mg/day and 12.9+/-5.0 mg/day, respectively. Average daily cost of all inpatient drugs was significantly higher for olanzapine than for risperidone (i.e. IEP5.61 [7.12] vs IEP3.38 [4.29]; p<0.0001), as was mean total costs of all inpatient drugs (i.e. IEP114.8 [145.8] vs IEP62.0 [78.7]; p<0.0001). This partly reflected the mean, non-significant, longer treatment duration for olanzapine compared with risperidone (mean 30.0 vs 26.4 days; p=0.27). Concomitant neuroleptic use was similar for both groups (71% risperidone, 73% olanzapine; p=0.54).

Risperidone was associated with significantly lower drug treatment costs.