Patient- and facility-level factors associated with diffusion of a new antipsychotic in the VA health system.

OBJECTIVE: When new medications are introduced, a period of diffusion, evaluation, and adoption follows. This study evaluated the influence of patient- and facility-level characteristics on the early use of a new antipsychotic, ziprasidone, among Department of Veterans Affairs (VA) patients with schizophrenia.
METHODS: Data on demographic characteristics, diagnoses, and outpatient pharmacy dispensings were obtained from the VA National Psychosis Registry for VA patients who received both a diagnosis of schizophrenia and oral antipsychotic medications during the fiscal years (FYs) 2001 (N=77,397), 2002 (N=74,724), and 2003 (N=74,399). Generalized estimating equations were used to examine associations between patient- and facility-level factors and ziprasidone use for each fiscal year.
RESULTS: In FY2001, 1.2 percent of patients used ziprasidone. Ziprasidone use more than tripled to 4.0 percent by FY2002 and more than quadrupled to 5.9 percent by FY2003. In all study years, patients who were white, younger, and female were more likely to receive ziprasidone. Patients who had previous psychiatric hospitalizations or who had diabetes were also more likely to receive ziprasidone. Differences by race diminished over time. Facility academic affiliation and region were only minimally associated with use.
CONCLUSIONS: Ziprasidone use increased rapidly among patients with schizophrenia after FDA approval, which suggests that both patients and providers remain eager to try new antipsychotic medications. Earlier dissemination was associated with clinical factors, such as comorbid diabetes, and with nonclinical factors, such as race or ethnicity. Differences by race diminished over time. The underlying processes and implications for affected patient groups are unclear.