One-year clinical and economic consequences of oral atypical antipsychotics in the treatment of schizophrenia

Objective: To assess the clinical and economic consequences of oral atypical antipsychotic treatment (aripiprazole, olanzapine, paliperidone ER, quetiapine, risperidone, and ziprasidone) in schizophrenia over one-year from a US healthcare system perspective. Methods: The decision model captured rates of discontinuation, symptom response, frequency and duration of relapse, adverse events (extrapyramidal symptoms and weight gain), resource utilization, and unit costs. Published randomized, double-blind, placebo-controlled clinical trial data were used to obtain response rates for comparators. Published clinical trial data from long-term effectiveness trials reflective of typical clinical settings were used for time on therapy, rates of discontinuation, likelihood of switching, relapse rates, and adverse event rates. Drug costs were based on Wholesale Acquisition Cost weighted by Wolters Kluwer Retail and First Databank Pricing drug utilization data. PharMetrics Patient-Centric database was utilized for length of stay, frequency of relapse, and unit cost of healthcare resource data. A clinical expert panel provided resource-use information not available in published literature or healthcare databases. To test the robustness of the findings, sensitivity analyses were performed using plausible ranges of key model input parameters. Results: The model estimated that, over 1 year, clinical outcomes of patients administered oral atypical antipsychotics would not vary considerably. This is partly due to differences 'washing out' because of frequent switching and discontinuation of medication. Economic outcomes did vary among pharmacotherapies: paliperidone ER was associated with cost savings in direct medical costs per patient per year compared to risperidone (cost savings using paliperidone ER vs. risperidone: $793), quetiapine ($1191), olanzapine ($1259), ziprasidone ($2159), and aripiprazole ($2204)). Limitations of this analysis include the absence of direct head-to-head long-term comparative data for antipsychotics. However, the results of the decision analysis held true when tested through a multitude of sensitivity analyses. Conclusion: This modeling study showed that paliperidone ER had the most favorable clinical and economic outcomes compared to other oral atypical antipsychotics for patients with schizophrenia. The analysis supports the notion that frequent discontinuation of medication is a problem with all oral antipsychotic treatments for schizophrenia.