Payer types associated with antipsychotic polypharmacy in an ambulatory care setting

Abstract

Abstract Objectives Antipsychotic polypharmacy is increasingly prescribed despite little documented evidence of a therapeutic benefit. There is also a limited understanding of the role that health insurance plays on the prevalence of antipsychotic polypharmacy. This study was undertaken to investigate the relationship between antipsychotic polypharmacy and individuals' intended source of payment in a US national sample of ambulatory care patients. Methods The study combined 2002, 2003 and 2004 data from the National Ambulatory Medical Care Survey (NAMCS) among adults seeking outpatient-based physician medical care services in the USA. We investigated characteristic differences among patients who were prescribed multiple antipsychotics versus individuals receiving only a single antipsychotic medication. Multivariable logistic regression examined the association between antipsychotic polypharmacy and patients' primary payment type classified as private insurance, Medicaid, Medicare or other (primarily out-of-pocket) payment type. Key findings Use of more than one antipsychotic agent was recorded in 68 of 830 (8.2%) outpatient physician visits in the 3-year period 2002–2004. Among the payer types studied, Medicaid payment status was correlated with increased risk of antipsychotic polypharmacy (odds ratio 2.7, 95% confidence interval 1.1–6.7). Conclusions Insurance status was associated with antipsychotic polypharmacy among non-institutionalized US residents prescribed antipsychotic medications. Patients reporting Medicaid as their primary payer were nearly three times as likely to be prescribed multiple antipsychotic drugs, potentially increasing their risk of adverse side effects as well as greater taxpayer burden. Future research should determine whether these trends continued after 2004 and to determine the costs of treating patients in the public sector with multiple antipsychotic drugs, a common scenario despite financial pressures and uncertain medical benefit.