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67. Polypharmacy Prescribing of Antipsychotic Medications among Thirteen Veterans Affairs Hospitals

W Feng, HSR&D Center for Mental Health Care and Outcomes Research (CeMHOR), Central Arkansas Veterans Health Care System, Little Rock, AR and the Centers for Mental Health Care Research, Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, AR; RR Owen, HSR&D Center for Mental Health Care and Outcomes Research (CeMHOR), Central Arkansas Veterans Health Care System, Little Rock, AR and the Centers for Mental Health Care Research, Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, AR; M Austen, HSR&D Center for Mental Health Care and Outcomes Research (CeMHOR), Central Arkansas Veterans Health Care System, Little Rock, AR and the Centers for Mental Health Care Research, Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, AR

Objectives: Pharmacotherapy is instrumental for effective treatment for schizophrenia. In this study, we investigated multiple antipsychotic prescribing among 13 Veterans Affairs Medical Centers. We further analyzed whether patient sociodemographic factors were associated with receiving multiple antipsychotic agents.

Methods: This analysis included 13 VA Medical Centers (VAMC) that participated in a large project funded by the VA, the Schizophrenia Guidelines Project. These thirteen VAMCs satisfy the following criteria: at least 125 patients with a primary diagnosis of schizophrenia were discharged from inpatient psychiatry units in 1997; mental health managers were interested in participating in the project; and a second VAMC in the candidate's Veterans Integrated Service Network also met these criteria; the site agreed to provide extracts of pharmacy and service utilization data from the local Veterans Information System Technology and Architecture (VISTA) databases. For each site, data were extracted for all patients discharged from inpatient psychiatry units with a primary diagnosis of schizophrenia (ICD-9 codes 295.1-295.3, 295.6 or 295.9) between January 1 and December 31, 1997. For patients hospitalized more than once during this period, the most recent hospitalization was used. Measure of polypharmacy as well as indicators reflecting the use of atypical antipsychotic medications were constructed from all inpatient antipsychotic medications that were prescribed between seven days prior to the discharge and the discharge date. Chi-square tests were used to compare facilities on polypharmacy prescription. A logistic regression model for use of polypharmacy was developed, with age, ethnicity, gender, marital status, atypical, and facilities as independent variables.

Results: Total 590 patients were included in the study across all 13 facilities. The average age was 48 (range 22-89). The majority were males (N=568; 96 percent) and only fifteen percent were married. Half were Caucasians. Also about half (N=291) were prescribed novel antipsychotic medications. In the entire sample, 20 percent (N=116) of the patients were prescribed multiple antipsychotic medications. There was wide variation among the facilities in the use of polypharmacy (range 6-45 percent, c2=40, df=12, p<0.0001). Results from the logistic regression model show that polypharmacy was more common among those who received novel antipsychotic medications (OR=8.13, chi-square=53, df=1, p<0.0001), and prescription of polypharmacy was significantly associated with facilities (chi-square=27, df=12, p<0.0071). Prescription of polypharmacy was not significantly influenced by age, gender, race or marital status.

Conclusions: The proportion of patients receiving more than one antipsychotic medication is relatively high. In addition, there was significant variation among facilities suggesting that institutional factors may influence prescribing practices. Prescription of polypharmacy was more common in those receiving novel antipsychotic agents. However, there is no evidence or guideline recommendation to support this practice.

Impact: Our study found substantial practice variation in polypharmacy prescribing of antipsychotic medications across the 13 VAMCs examined. This finding adds to the growing evidence suggesting that the local organizational climate may have a profound effect on prescribing practices. Additional research is needed to determine the clinical appropriateness of these practices, and to test interventions to improve practice.