title: How rebates, copayments, and administration costs affect the cost-effectiveness of osteoporosis therapies.
abstract: OBJECTIVE
  Because of rising drug expenditures, cost considerations have become essential, necessitating the requirement for cost-effectiveness analyses for managed care organizations (MCOs). The study objective is to examine the impact of various drug-cost components, in addition to wholesale acquisition cost (WAC), on the cost-effectiveness of osteoporosis therapies.
  
  
  METHODS
  A Markov model of osteoporosis was used to exemplify different drug cost scenarios.
  
  
  METHODS
  We examined the effect of varying rebates for oral bisphosphonates--risedronate and ibandronate--as well as considering the impact of varying copayments and administration costs for intravenous zoledronate. The population modeled was 1,000 American women, > or = 50 years with osteoporosis. Patients were followed for 1 year to reflect an annual budget review of formularies by MCOs. The cost of therapy was based on an adjusted WAC, and is referred to as net drug cost. The total annual cost incurred by an MCO for each drug regimen was calculated using the net drug cost and fracture cost. We estimated cost on a quality adjusted life year (QALY) basis.
  
  
  RESULTS
  When considering different rebates, results for risedronate versus ibandronate vary from cost-savings (i.e., costs less and more effective) to approximately $70,000 per QALY. With no risedronate rebate, an ibandronate rebate of approximately 65% is required before cost per QALY surpasses $50,000. With rebates greater than 25% for risedronate, irrespective of ibandronate rebates, results become cost-saving. Results also showed the magnitude of cost savings to the MCO varied by as much as 65% when considering no administration cost and the highest coinsurance rate for zoledronate.
  
  
  CONCLUSIONS
  Our study showed that cost-effectiveness varies considerably when factors in addition to the WAC are considered. This paper provides recommendations for pharmaceutical manufacturers and MCOs when developing and interpreting such analyses.
authors.affiliation: Cornerstone Research Group, Burlington, Ontario. nferko@cornerstone-research.com
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Ferko
authors.forename: Natalie
authors.initials: N
authors.lastname: Borisova
authors.forename: Parisa
authors.initials: P
authors.lastname: Airia
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Grima
authors.forename: Melissa F
authors.initials: MF
authors.lastname: Thompson
mesh_terms: D050071:Bone Density Conservation Agents / Q000191:economics* / Q000627:therapeutic use; D017047:Cost Sharing; D003362:Cost-Benefit Analysis; D004164:Diphosphonates / Q000191:economics* / Q000627:therapeutic use; D016527:Drug Costs; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000191:economics / Q000627:therapeutic use; D005260:Female; D005598:Fractures, Spontaneous / Q000191:economics; D006801:Humans; D000077557:Ibandronic Acid; D008390:Markov Chains; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy*; D012051:Reimbursement Mechanisms; D000068296:Risedronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D000068296:Risedronic Acid; D012968:Etidronic Acid; D000077557:Ibandronic Acid