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.
Valenstein
Marcia
M
SMITREC/VA Ann Arbor Center for Excellence, P.O. Box 130170, Ann Arbor, Michigan 48113-0170, USA. marciav@med.umich.edu
McCarthy
John F
JF
Ignacio
Rosalinda V
RV
Dalack
Gregory W
GW
Stavenger
Thomas
T
Blow
Frederic C
FC
D000368:Aged; D000465:Algorithms; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D017277:Drug Approval; D004358:Drug Therapy / Q000639:trends*; D017723:Drug Utilization Review; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008605:Mental Health Services / Q000331:legislation & jurisprudence* / Q000458:organization & administration*; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use*; D012042:Registries; D012559:Schizophrenia / Q000188:drug therapy*; D013844:Thiazoles / Q000627:therapeutic use*; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans / Q000523:psychology*
D014150:Antipsychotic Agents; D010879:Piperazines; D013844:Thiazoles; C092292:ziprasidone