Cost effectiveness of long-acting risperidone injection versus alternative antipsychotic agents in patients with schizophrenia in the USA

The availability of long-acting risperidone injection may increase adherence and lead to improved clinical and economic outcomes for individuals with schizophrenia. The objective of this study was to assess the cost effectiveness of longacting risperidone, oral risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, and haloperidol depot in patients with schizophrenia over 1 year from a healthcare system perspective. Published medical literature, unpublished data from clinical trials and a consumer health database, and a clinical expert panel were utilized to populate a decision analytical model comparing the seven treatment alternatives. The model captured rates of patient compliance, the rates, frequency and duration of relapse, incidence of adverse events, and healthcare resource utilization and associated costs. Primary outcomes were expressed in terms of percentage of patients relapsing per year, number of relapse days per year (number and duration of relapses per patient per year), and total direct 2003 medical cost per patient per year. On the basis of model projections, the proportions of patients experiencing a relapse requiring hospitalization in 1 year were 66% for haloperidol depot, 41% for oral risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole, and 26% for long-acting risperidone, whereas the proportions of patients with an exacerbation not requiring hospitalization were 60% for haloperidol depot, 37% for oral risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole, and 24% for long-acting risperidone. The mean number of days of relapse requiring hospitalization per patient per year were 28 for haloperidol depot, 18 for oral risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole, and 11 for long-acting risperidone, whereas the mean number of days of exacerbation not requiring hospitalization were eight for haloperidol depot, five for oral risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole, and three for long-acting risperidone. This would translate into direct medical cost savings with long-acting risperidone compared with oral risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, and haloperidol depot of US$161, 1425, 508, 259, 1068, and 8224, respectively. These findings were supported by sensitivity analyses. The utilization of long-acting risperidone is predicted to result in better clinical outcomes and lower total healthcare costs than its comparators, oral risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, and haloperidol depot. Longacting risperidone may therefore be a cost saving therapeutic option for patients with schizophrenia.