title: Polypharmacy with antipsychotic drugs in patients with schizophrenia: trends in multiple health care systems.
abstract: OBJECTIVE
  Patterns of pharmacologic treatment in U.S. outpatients with schizophrenia across multiple health care settings were investigated.
  
  
  METHODS
  Antipsychotic drug utilization by patients with schizophrenia and related disorders was analyzed using data on 119,662 patients served by the Veterans Affairs (VA) health care system in fiscal years 2005-09, data on 5,440 enrollees in two health maintenance organizations (HMOs) in 2002-09, and National Ambulatory Medical Care Survey (NAMCS) data reflecting the experience of 17.6 million U.S. residents seeking care outside federal systems during the same eight-year period. Polypharmacy was defined as the use of more than one antipsychotic agent during one year (in the VA sample) or one week (in the HMO and NAMCS samples). The association of polypharmacy with hospital admissions was assessed via multivariable logistic regression.
  
  
  RESULTS
  Rates of antipsychotic use in the VA sample ranged from 74% to 78%, with lower and more variable rates in the NAMCS sample (69-84%) and the HMO sample (22-67%). VA patients were found to have lower polypharmacy rates (20-22%) than patients in the HMO and NAMCS samples (19-31%). In all samples evaluated, polypharmacy was associated with an increased likelihood of hospital admission (odds ratio range, 1.4-2.4).
  
  
  CONCLUSIONS
  A multisystem study revealed that antipsychotic use among patients with schizophrenia varied substantially among health care systems and that nearly one fifth of patients with schizophrenia or other psychotic disorders in most of the health care systems experienced antipsychotic polypharmacy.
authors.affiliation: FangFang Sun, M.S., is Health Services Researcher, Center for Applied Health Research, Temple, TX. Eileen M. Stock, Ph.D., is Research Scientist, Center for Applied Health Research, and Assistant Professor, College of Medicine, Texas A&M Health Sciences Center, Bryan. Laurel A. Copeland, Ph.D., is Interim Associate Chief of Staff of Research, Central Texas Veterans Health Care System, Temple, and Associate Director, Center for Applied Health Research, and Associate Professor, College of Medicine, Texas A&M Health Sciences Center. John E. Zeber, Ph.D., is Co-Director, Health Outcomes Core (jointly sponsored by Central Texas Veterans Health Care System and Scott & White Healthcare), Temple, and Associate Professor, College of Medicine, Texas A&M Health Sciences Center. Brian K. Ahmedani, Ph.D., LMSW, is Research Scientist, Center for Health Policy & Health Services Research, Henry Ford Health System, Detroit, MI. Sandra B. Morissette, Ph.D., is Assessment Core Chief, Veterans Affairs VISN 17 Center of Excellence for Research on Returning War Veterans, Waco, TX, and Associate Professor, College of Medicine, Texas A&M Health Sciences Center.
authors.forename: FangFang
authors.initials: F
authors.lastname: Sun
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Stock
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Copeland
authors.forename: John E
authors.initials: JE
authors.lastname: Zeber
authors.forename: Brian K
authors.initials: BK
authors.lastname: Ahmedani
authors.forename: Sandra B
authors.initials: SB
authors.lastname: Morissette
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003695:Delivery of Health Care; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019338:Polypharmacy; D012559:Schizophrenia / Q000188:drug therapy*; D014481:United States; D014493:United States Department of Veterans Affairs; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents
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