title: Potential savings associated with drug substitution in Medicare Part D: the Translating Research into Action for Diabetes (TRIAD) study.
abstract: BACKGROUND
  Drug substitution is a promising approach to reducing medication costs.
  
  
  OBJECTIVE
  To calculate the potential savings in a Medicare Part D plan from generic or therapeutic substitution for commonly prescribed drugs.
  
  
  METHODS
  Cross-sectional, simulation analysis.
  
  
  METHODS
  Low-income subsidy (LIS) beneficiaries (n = 145,056) and non low-income subsidy (non-LIS) beneficiaries (n = 1,040,030) enrolled in a large, national Part D health insurer in 2007 and eligible for a possible substitution.
  
  
  METHODS
  Using administrative data from 2007, we identified claims filled for brand-name drugs for which a direct generic substitute was available. We also identified the 50 highest cost drugs separately for LIS and non-LIS beneficiaries, and reached consensus on which drugs had possible therapeutic substitutes (27 for LIS, 30 for non-LIS). For each possible substitution, we used average daily costs of the original and substitute drugs to calculate the potential out-of-pocket savings, health plan savings, and when applicable, savings for the government/LIS subsidy.
  
  
  RESULTS
  Overall, 39 % of LIS beneficiaries and 51 % of non-LIS beneficiaries were eligible for a generic and/or therapeutic substitution. Generic substitutions resulted in an average annual savings of $160 in the case of LIS beneficiaries and $127 in the case of non-LIS beneficiaries. Therapeutic substitutions resulted in an average annual savings of $452 in the case of LIS beneficiaries and $389 in the case of non-LIS beneficiaries.
  
  
  CONCLUSIONS
  Our findings indicate that drug substitution, particularly therapeutic substitution, could result in significant cost savings. There is a need for additional studies evaluating the acceptability of therapeutic substitution interventions within Medicare Part D.
authors: David Geffen School of Medicine, University of California, Los Angeles, CA, USA, kduru@mednet.ucla.edu.
authors: O Kenrik
authors: OK
authors: Duru
authors: Susan L
authors: SL
authors: Ettner
authors: Norman
authors: N
authors: Turk
authors: Carol M
authors: CM
authors: Mangione
authors: Arleen F
authors: AF
authors: Brown
authors: Jeffery
authors: J
authors: Fu
authors: Leslie
authors: L
authors: Simien
authors: Chien-Wen
authors: CW
authors: Tseng
mesh_terms: D000368:Aged; D017046:Cost Savings / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D016527:Drug Costs / Q000706:statistics & numerical data*; D011307:Drug Prescriptions / Q000191:economics / Q000706:statistics & numerical data; D057915:Drug Substitution / Q000191:economics*; D016568:Drugs, Generic / Q000191:economics; D005260:Female; D006302:Health Services Research / Q000379:methods; D006801:Humans; D008297:Male; D054524:Medicare Part D / Q000191:economics*; D011203:Poverty; D011306:Prescription Fees / Q000706:statistics & numerical data; D057170:Translational Research, Biomedical / Q000379:methods; D014481:United States
chemical_list: D016568:Drugs, Generic
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