title: County-Level Population Economic Status and Medicare Imaging Resource Consumption.
abstract: OBJECTIVE
  The aim of this study was to assess relationships between county-level variation in Medicare beneficiary imaging resource consumption and measures of population economic status.
  
  
  METHODS
  The 2013 CMS Geographic Variation Public Use File was used to identify county-level per capita Medicare fee-for-service imaging utilization and nationally standardized costs to the Medicare program. The County Health Rankings public data set was used to identify county-level measures of population economic status. Regional variation was assessed, and multivariate regressions were performed.
  
  
  RESULTS
  Imaging events per 1,000 Medicare beneficiaries varied 1.8-fold (range, 2,723-4,843) at the state level and 5.3-fold (range, 1,228-6,455) at the county level. Per capita nationally standardized imaging costs to Medicare varied 4.2-fold (range, $84-$353) at the state level and 14.1-fold (range, $33-$471) at the county level. Within individual states, county-level utilization varied on average 2.0-fold (range, 1.1- to 3.1-fold), and costs varied 2.8-fold (range, 1.1- to 6.4-fold). For both large urban populations and small rural states, Medicare imaging resource consumption was heterogeneously variable at the county level. Adjusting for county-level gender, ethnicity, rural status, and population density, countywide unemployment rates showed strong independent positive associations with Medicare imaging events (β = 26.96) and costs (β = 4.37), whereas uninsured rates showed strong independent positive associations with Medicare imaging costs (β = 2.68).
  
  
  CONCLUSIONS
  Medicare imaging utilization and costs both vary far more at the county than at the state level. Unfavorable measures of county-level population economic status in the non-Medicare population are independently associated with greater Medicare imaging resource consumption. Future efforts to optimize Medicare imaging use should consider the influence of local indigenous socioeconomic factors outside the scope of traditional beneficiary-focused policy initiatives.
authors.affiliation: Department of Radiology, NYU Langone Medical Center, New York, New York. Electronic address: andrew.rosenkrantz@nyumc.org.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.affiliation: Harvey L. Neiman Health Policy Institute, Reston, Virginia; Department of Health Administration and Policy, George Mason University, Fairfax, Virginia.
authors.forename: Danny R
authors.initials: DR
authors.lastname: Hughes
authors.affiliation: Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Anand M
authors.initials: AM
authors.lastname: Prabhakar
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Richard
authors.initials: R
authors.lastname: Duszak
mesh_terms: D003365:Costs and Cost Analysis; D003952:Diagnostic Imaging / Q000191:economics / Q000706:statistics & numerical data*; D018588:Fee-for-Service Plans / Q000191:economics / Q000706:statistics & numerical data*; D006295:Health Resources; D006801:Humans; D006278:Medicare / Q000191:economics / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D014481:United States
keywords: Medicare; Socioeconomics; geographic variation; imaging utilization; public health