title: Regional variation in use of a new class of antidiabetic medication among medicare beneficiaries: the case of incretin mimetics.
abstract: BACKGROUND
  When incretin mimetic (IM) medications were introduced in 2005, their effectiveness compared with other less-expensive second-line diabetes therapies was unknown, especially for older adults. Physicians likely had some uncertainty about the role of IMs in the diabetes treatment armamentarium. Regional variation in uptake of IMs may be a marker of such uncertainty.
  
  
  OBJECTIVE
  To investigate the extent of regional variation in the use of IMs among beneficiaries and estimate the cost implications for Medicare.
  
  
  METHODS
  This was a cross-sectional analysis of 2009-2010 claims data from a nationally representative sample of 238 499 Medicare Part D beneficiaries aged ≥65 years, who were continuously enrolled in fee-for-service Medicare and Part D and filled ≥1 antidiabetic prescription. Beneficiaries were assigned to 1 of 306 hospital-referral regions (HRRs) using ZIP codes. The main outcome was adjusted proportion of antidiabetic users in an HRR receiving an IM.
  
  
  RESULTS
  Overall, 29 933 beneficiaries (12.6%) filled an IM prescription, including 26 939 (11.3%) for sitagliptin or saxagliptin and 3718 (1.6%) for exenatide or liraglutide. The adjusted proportion of beneficiaries using IMs varied more than 3-fold across HRRs, from 5th and 95th percentiles of 5.2% to 17.0%. Compared with non-IM users, IM users faced a 155% higher annual Part D plan ($1067 vs $418) and 144% higher patient ($369 vs $151) costs for antidiabetic prescriptions.
  
  
  CONCLUSIONS
  Among older Part D beneficiaries using antidiabetic drugs, substantial regional variation exists in the use of IMs, not accounted for by sociodemographics and health status. IM use was associated with substantially greater costs for Part D plans and beneficiaries.
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA zam12@pitt.edu.
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Marcum
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Driessen
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA VA Pittsburgh Healthcare System, Pittsburgh, PA, USA.
authors.forename: Carolyn T
authors.initials: CT
authors.lastname: Thorpe
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Donohue
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA VA Pittsburgh Healthcare System, Pittsburgh, PA, USA.
authors.forename: Walid F
authors.initials: WF
authors.lastname: Gellad
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000188:drug therapy* / Q000191:economics / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000191:economics / Q000627:therapeutic use*; D054795:Incretins / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D054524:Medicare Part D / Q000191:economics; D008687:Metformin / Q000191:economics / Q000627:therapeutic use; D013453:Sulfonylurea Compounds / Q000191:economics / Q000627:therapeutic use; D045162:Thiazolidinediones / Q000191:economics / Q000627:therapeutic use; D014481:United States / Q000453:epidemiology
chemical_list: D007004:Hypoglycemic Agents; D054795:Incretins; D013453:Sulfonylurea Compounds; D045162:Thiazolidinediones; D008687:Metformin
keywords: Medicare; diabetes; pharmacoepidemiology; regional variation