The impact of atypical antipsychotic medications on the use of health care by patients with schizophrenia.
OBJECTIVE
Using data in real-world clinical practice, this study aims to compare the health-care use patterns of patients with schizophrenia who use oral antipsychotics.


METHODS
A total of 219,504 episodes of antipsychotic drug therapy initiated during the period from 2000 to 2002 were identified using data from the California Medicaid program. Four types of episodes were analyzed based on the patient's drug use history as far back as 1994: restarting therapy after a break in therapy using the same drug used in the preceding episode; switching therapy after a break in treatment using a different medication; switching therapy without a break in therapy; and augmentation. Health-care use patterns over a 1-year post-treatment period were analyzed using ordinary least squares (OLS) regressions, Cox proportional hazards models, and logistic regression.


RESULTS
The impact of atypical antipsychotics on health-care use in the first post-treatment year varies by episode type. Patients switching to atypical medications generally cost significantly more than similar patients switching to a conventional antipsychotic. Olanzapine and risperidone, however, were associated with reductions in total costs relative to conventional antipsychotics when used in restart and augmentation episodes. Differences across all three second-generation antipsychotics were relatively small.


CONCLUSIONS
Small differences across the atypical antipsychotics suggest that these drugs are interchangeable, raising the question of whether drug costs could be reduced through selectively contracting for a preferred drug. Potential savings may be limited by several factors. First, most episodes of treatment are restart episodes. Switching these patients to a preferred drug may have clinical risk. Second, patients with schizophrenia switch and augment therapies frequently, thus quickly reducing the population of patients who could be effectively treated with a single preferred drug.
Chen
Lei
L
Department of Pharmaceutical Economics and Policy, School of Pharmacy, University of Southern California, Los Angeles, CA, USA.
McCombs
Jeffrey S
JS
Park
Jinhee
J
D014150:Antipsychotic Agents / Q000191:economics / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000191:economics / Q000627:therapeutic use*; D003024:Clozapine / Q000191:economics / Q000627:therapeutic use; D003987:Dibenzothiazepines / Q000191:economics / Q000627:therapeutic use; D016527:Drug Costs; D017723:Drug Utilization Review; D017050:Episode of Care; D017048:Health Care Costs; D006295:Health Resources / Q000191:economics / Q000706:statistics & numerical data*; D006801:Humans; D000077152:Olanzapine; D000069348:Quetiapine Fumarate; D018967:Risperidone / Q000191:economics / Q000627:therapeutic use; D012559:Schizophrenia / Q000188:drug therapy* / Q000191:economics
D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D001569:Benzodiazepines; D000069348:Quetiapine Fumarate; D003024:Clozapine; D018967:Risperidone; D000077152:Olanzapine