title: Impact of cost sharing on specialty drug utilization and outcomes: a review of the evidence and future directions.
abstract: OBJECTIVE
  Specialty drugs often represent major medical advances for patients with few other effective options available, but high costs have attracted the attention of both payers and policy makers. We reviewed the evidence regarding the impact of cost sharing on utilization of specialty drugs indicated for rheumatoid arthritis (RA), multiple sclerosis (MS), and cancer, and on the use of nondrug medical services, health outcomes, and spending.
  
  
  METHODS
  Systematic review of Medline-indexed studies identified via an OVID search for articles published in English from 1995 to 2014, using combinations of terms for cost sharing and specialty drugs, and/or our 3 conditions of interest. We identified additional studies from reference lists.
  
  
  RESULTS
  We identified 19 articles focusing on specialty drugs indicated for MS (n = 9), cancer (n = 8), and RA (n = 8). Studies examined prescription abandonment (n = 3), initiation or any utilization (n = 8), adherence (n = 9), persistence/discontinuation (n = 7), number of claims (n = 1), and drug spending (n = 1). Findings varied by disease, but generally indicated stronger effects for noninitiation or abandonment of a prescription at the pharmacy and somewhat smaller effects for refill behavior and drug spending once patients initiated therapy. Studies have not examined specialty tier cost sharing seen under Medicare Part D or health insurance exchanges, nor effects on medical utilization, spending, or health outcomes.
  
  
  CONCLUSIONS
  Evidence to date generally indicates reductions in specialty drug utilization associated with higher cost sharing; effects have varied by type of disease and specialty drug use outcome. We draw upon our findings and the gaps in evidence to summarize future directions for research and policy.
authors.affiliation: Center for Evidence-based Practice, Director, Value-based Insurance Design Initiatives, Center for Health Incentives and Behavioral Economics, University of Pennsylvania, 1223 Blockley Hall, Philadelphia, PA 19104. E-mail: jdoshi@mail.med.upenn.edu.
authors.forename: Jalpa A
authors.initials: JA
authors.lastname: Doshi
authors.forename: Pengxiang
authors.initials: P
authors.lastname: Li
authors.forename: Vrushabh P
authors.initials: VP
authors.lastname: Ladage
authors.forename: Amy R
authors.initials: AR
authors.lastname: Pettit
authors.forename: Erin A
authors.initials: EA
authors.lastname: Taylor
mesh_terms: D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D017047:Cost Sharing / Q000191:economics*; D016527:Drug Costs; D004363:Drug Utilization / Q000191:economics*; D019317:Evidence-Based Medicine; D005260:Female; D005102:Health Expenditures / Q000639:trends*; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000188:drug therapy; D009369:Neoplasms / Q000188:drug therapy; D055553:Prescription Drugs / Q000008:administration & dosage / Q000191:economics*; D014481:United States
chemical_list: D055553:Prescription Drugs