Objective: To discern predictors of use of concomitant atypical antipsychotic pharmacotherapy among US Medicaid beneficiaries diagnosed with schizophrenia.
Methods: Data were abstracted from the 2010 US National Ambulatory Medical Care Survey (NAMCS) for all state Medicaid program beneficiaries with a diagnosis of schizophrenia (ICD-9-CM codes 295.00–295.99). The US NAMCS is a national cross-sectional probability sample designed and conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. Data are collected by the US Census Bureau. Primary patient-level characteristics of interest were: use of concomitant antipsychotic pharmacotherapy, patient age, gender, race/ethnicity, physician specialty (per the physician–patient encounter reported in the US NAMCS), urban or rural location, and comorbidity.
Results: In 2010, there were 1,353,299 US Medicaid beneficiaries with a diagnosis of schizophrenia. The mean age of beneficiaries was 47.6 years; 62.1% were male, and 58.9% were white non-Hispanic. Of these, 1,079,576 (79.8%) were prescribed an antipsychotic, 72.4% were prescribed an atypical antipsychotic, and 10.7% were prescribed >1 atypical antipsychotic. Predictors of receipt for >1 atypical antipsychotic were physician specialty being psychiatry (odds ratio [OR], 7.9; 95% confidence interval [CI], 6.2–15.3; p<0.05) and urban location (OR, 4.8; 95% CI, 3.5–9.1; p<0.05).
Conclusion: In 2010, 10.7% of US Medicaid beneficiaries diagnosed with schizophrenia were prescribed >1 atypical antipsychotic. A physician specialty of psychiatry increased the probability of receipt of >1 atypical antipsychotic 8-fold, while an urban location increased the probability 5-fold, compared with non-urban location, potentially reflecting greater distribution of physician specialists within urban settings.