Ethnic Differences in Use of Antipsychotic Medication Among Texas Medicaid Clients With Schizophrenia

Background: Culture and ethnicity have been suggested to influence the presentation of patients with schizophrenia. These factors are thought to affect the diagnoses, courses of treatment, and medical utilization patterns of patients with schizophrenia. Specifically, the differences between whites, African Americans, and Mexican Americans are of particular importance, as these groups comprise the majority of the population in the United States today. The traditional course of treatment for many patients with schizophrenia is the drug haloperidol. However, research has shown that some ethnic groups (African Americans and Mexican Americans) may respond better to atypical drugs, such as olanzapine, but may be less likely to receive these drugs. A better response to the course of treatment results in improved medical utilization patterns. The purpose of this study was to examine if ethnicity helped predict whether Texas Medicaid patients were prescribed haloperidol versus olanzapine when other factors were controlled for.

Method: The study population consisted of 726 patients whose index drug was haloperidol and 1875 patients whose index drug was olanzapine. Patients had an ICD-9-CM diagnosis of schizophrenia or schizoaffective disorder. Texas medical and prescription claims data were used in a logistic regression analysis to determine significant predictors of the type of antipsychotic (haloperidol vs. olanzapine) patients were prescribed. Variables included in the analysis were ethnicity, gender, age, region, other mental illness comorbidities, and previous utilization of medications and resources. Data were collected from Jan. 1, 1996, to Aug. 31, 1998.

Results: The results show that when other demographic and utilization factors were controlled for, African Americans were less likely than whites to receive olanzapine rather than haloperidol.

Conclusion: Ethnicity is a significant predictor of the type of antipsychotic that is prescribed.