title: Regional variation in antibiotic prescribing among medicare part D enrollees, 2013.
abstract: BACKGROUND
  Antibiotics are among the most widely prescribed medications. The geographic variation in antibiotic prescribing patterns and associated costs among Medicare Part D recipients have not been described. The purpose of this study was to assess the regional variation in antibiotic prescriptions and costs among Medicare Part D enrollees in 2013.
  
  
  METHODS
  Retrospective cohort review of all Medicare Part D enrollees in 2013, using the Medicare Provider Utilization and Payment Data: Part D Prescriber Public Use File. All original or refill prescription claims for antibiotics as listed in the Part D Prescriber Public Use File were included. Our primary outcomes were total antibiotic claims and antibiotic cost per Medicare Part D Enrollee. Data were analyzed descriptively by state and by geographic region as defined by the United States Census Bureau. Antibiotic claims were described overall and by antibiotic class.
  
  
  RESULTS
  Over 54 million outpatient antibiotic claims were filed for Part D enrollees in 2013, representing more than $1.5 billion in total antibiotic expenditures. Antibiotic use was highest in the South (1,623 claims/1,000 enrollees), followed by the Midwest (1,401 claims/1,000 enrollees), Northeast (1,366 claims/1,000 enrollees), and West (1,292 claims/1,000 enrollees). Average antibiotic costs per enrollee in each region were as follows: South $46.58, Northeast $43.70, Midwest $40.54, and West $36.42. Fluoroquinolones were the most commonly prescribed class overall (12.2 million claims).
  
  
  CONCLUSIONS
  Antibiotic use among elderly Medicare enrollees in the United States was highest in the South region. Fluoroquinolones were the most common antibiotics used in all regions. These patterns could be utilized in the development of targeted antimicrobial stewardship efforts.
authors.affiliation: College of Pharmacy, The University of Texas at Austin, Austin, TX, USA.|Pharmacotherapy Education and Research Center, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Andre
authors.initials: A
authors.lastname: Arizpe
authors.affiliation: College of Pharmacy, The University of Texas at Austin, Austin, TX, USA.|Pharmacotherapy Education and Research Center, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Reveles
authors.affiliation: Division of Pharmacy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 0090, Houston, TX, 77030, USA. slaitken@mdanderson.org.|Center for Antimicrobial Resistance and Microbial Genomics, UTHealth McGovern Medical School, Houston, TX, USA. slaitken@mdanderson.org.
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Aitken
mesh_terms: D000900:Anti-Bacterial Agents / Q000191:economics / Q000627:therapeutic use*; D003365:Costs and Cost Analysis; D011307:Drug Prescriptions / Q000191:economics / Q000706:statistics & numerical data*; D024841:Fluoroquinolones / Q000191:economics / Q000627:therapeutic use; D006801:Humans; D054524:Medicare Part D / Q000191:economics / Q000706:statistics & numerical data*; D010045:Outpatients / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones
keywords: Antibiotic stewardship; Cephalosporins; Claims data; Elderly; Fluoroquinolones; Macrolides; Outpatient prescriptions; Penicillins