title: Reliance on Veterans Affairs outpatient care by Medicare-eligible veterans.
abstract: OBJECTIVE
  To examine longitudinal changes in Medicare-eligible veterans' reliance on the Department of Veterans Affairs (VA) healthcare system for primary and specialty care over 4 years.
  
  
  METHODS
  We merged VA administrative and Medicare claims data to examine outpatient use during fiscal years (FY) 2001 to 2004 by 15,520 Medicare-eligible veterans who used VA primary care in FY2000. Reliance on VA outpatient care was defined as the proportion of total (VA/Medicare) visits received in VA for primary or specialty care.
  
  
  RESULTS
  Of 869,000 primary and specialty care visits in the study period, 39% occurred within VA and 77% were specialty care. Reliance on VA primary care was substantially higher than specialty care (66% vs. 50% in FY2001; P<0.001). Reliance on VA primary and specialty care decreased over time (57% vs. 31% in FY2004; P<0.001). Significant shifts occurred at both extremes of VA reliance. From FY2001 to FY2004, the proportion of patients in the top decile of reliance on VA primary care decreased from 39% to 31%, whereas the proportion in the bottom decile doubled from 8% to 18%. Similarly, the proportion of patients in the top decile of reliance on VA specialty care decreased from 24% to 13%, whereas the proportion in the bottom decile doubled from 22% to 47%.
  
  
  CONCLUSIONS
  Reliance on VA primary and specialty care among VA primary care patients decreased substantially over time, particularly for specialty care. Increasing use of non-VA services may complicate VA's implementation of patient-centered medical home models and performance measurement.
authors.affiliation: Northwest Center for Outcomes Research in Older Adults, VA Puget Sound Health Care System, University of Chicago, Chicago, IL 98101, USA. fliu@u.washington.edu
authors.forename: Chuan-Fen
authors.initials: CF
authors.lastname: Liu
authors.forename: Willard G
authors.initials: WG
authors.lastname: Manning
authors.forename: James F
authors.initials: JF
authors.lastname: Burgess
authors.forename: Paul L
authors.initials: PL
authors.lastname: Hebert
authors.forename: Chris L
authors.initials: CL
authors.lastname: Bryson
authors.forename: John
authors.initials: J
authors.lastname: Fortney
authors.forename: Mark
authors.initials: M
authors.lastname: Perkins
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Sharp
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Maciejewski
mesh_terms: D000368:Aged; D000553:Ambulatory Care / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D006297:Health Services Accessibility / Q000191:economics; D006301:Health Services Needs and Demand / Q000191:economics; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D006278:Medicare / Q000191:economics*; D008511:Medicine; D011320:Primary Health Care / Q000191:economics*; D014481:United States; D014493:United States Department of Veterans Affairs / Q000191:economics*; D014728:Veterans