title: Evaluating the Effects of Pioneer Accountable Care Organizations on Medicare Part D Drug Spending and Utilization.
abstract: The improvement of medication use is a critical mechanism that accountable care organization (ACO) could use to save overall costs. Currently pharmaceutical spending is not part of the calculation for ACO-shared savings and risks. Thus, ACO providers may have strong incentives to prescribe more medications hoping to avoid expensive downstream medical costs.
  
  
  
  We designed a quasinatural experiment study to evaluate the effects of Pioneer ACOs on Medicare Part D spending and utilization. Medicare fee-for-service beneficiaries with Part D drug coverage who were aligned to a Pioneer ACO were compared with a random 5% sample of non-ACO beneficiaries. Outcomes included changes in Part D spending, number of prescription fills, percent of brand medications, and total Part A and B medical spending. We utilized a generalized linear model with a difference-in-differences approach to estimate 2011-2012 changes in these outcomes among beneficiaries aligned with Pioneer ACOs, adjusting for all beneficiary-level demographics, income and insurance status, clinical characteristics, and regional fixed effects.
  
  
  
  Being in an ACO did not significantly affect Part D spending (-$23.52; P=0.19), total prescriptions filled (-0.12; P=0.27), and the percent of claims for brand-name drugs (0.06%; P=0.23). The ACO group was associated with savings in Parts A and B spending of $345 (P<0.0001) per person per year.
  
  
  
  We found that beneficiaries aligned to Pioneer ACOs were not associated with changes in pharmaceutical spending and use, but were associated with savings in Parts A and B spending in 2012.
authors.affiliation: *Department of Health Policy and Management, University of Pittsburgh, Pittsburgh, PA †Centers for Medicare and Medicaid Services, Office of Enterprise Data and Analytics, Baltimore, MD.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kadin J
authors.initials: KJ
authors.lastname: Caines
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Powers
mesh_terms: D060866:Accountable Care Organizations / Q000191:economics* / Q000706:statistics & numerical data; D017046:Cost Savings; D016527:Drug Costs; D004363:Drug Utilization / Q000191:economics* / Q000706:statistics & numerical data; D018588:Fee-for-Service Plans / Q000191:economics* / Q000706:statistics & numerical data; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006801:Humans; D054524:Medicare Part D / Q000191:economics*; D014481:United States