Economic outcomes of antipsychotic agents in a medicaid population: Traditional agents vs. Risperidone

Clinical trials reveal that the newer atypical antipsychotic agents are more effective and have fewer side effects than traditional agents. However, these newer agents have a higher acquisition cost than traditional agents. This study assessed the differential impact of risperidone and traditional agents on the total schizophrenia-related cost of care for Medicaid patients suffering from schizophrenia. This was a retrospective longitudinal pretest- posttest analysis of Medicaid claims data covering January 1992 to August 1996. Continuously eligible patients (n=150) with a documented diagnosis of schizophrenia were evaluated. Medical claims were analyzed for patients treated with traditional antipsychotics for at least 12 months and then switched to risperidone and followed for at least 12 months. Patients who failed on at least one traditional agent and who remained on other traditional agents throughout the study timeframe served as a control group. Monthly costs per patient were estimated using mixed model linear regression with age and gender serving as covariates. The total monthly costs per patient for the risperidone and traditional cohorts were similar ($1,050.52 and $946.24, respectively; p=.5438) during the pretest phase of the study. For patients treated with risperidone, drug costs were $177.35 higher (CL_0.95±$7.64; p=.0001) per patient per month in the posttest period compared with the pretest period. However inpatient hospital costs were $312.04 lower (CL_0.95±$146.76; p=.001) per patient per month in the posttest period compared with the pretest period. In addition, physician costs were $9.55 lower (CL_0.95±$5.31; p=.0004) per patient per month in the posttest period. The difference from the pretest to posttest period for outpatient mental health clinic costs was statistically similar. For those in the risperidone cohort, total estimated costs decreased by $204.87 per patient per month during treatment with risperidone (CL_0.95±$161.01; p=.0127). Over the same timeframe, total costs increased $160.68 per patient per month (CL_0.95±$196.04; n.s.; p=.1082) in the control cohort. While the mean monthly drug cost was significantly higher during treatment with risperidone, this increase was offset by cost reductions elsewhere in the system.