title: Use of health services by previously uninsured Medicare beneficiaries.
abstract: BACKGROUND
  Previously uninsured adults who enroll in the Medicare program at the age of 65 years may have greater morbidity, requiring more intensive and costlier care over subsequent years, than they would if they had been previously insured.
  
  
  METHODS
  We used longitudinal data from the nationally representative Health and Retirement Study to assess self-reported health care use and expenditures from 1992 through 2004 among 5158 adults who were privately insured or uninsured before Medicare coverage began at the age of 65 years. We used propensity-score methods to compare health care use and expenditures for previously insured and uninsured beneficiaries who were similar across numerous characteristics at 59 to 60 years of age and adjusted for differences in supplemental and prescription-drug coverage after 65 years of age.
  
  
  RESULTS
  Among 2951 adults with hypertension, diabetes, heart disease, or stroke diagnosed before 65 years of age, previously uninsured adults who acquired Medicare coverage at the age of 65 reported significantly greater increases in the numbers of doctor visits (P<0.001) and hospitalizations (P=0.001) and in total medical expenditures (P=0.02) than did previously insured adults. Significant differential increases were not evident among the 2207 adults without these conditions (P>0.12 for all comparisons). In analyses adjusted for supplemental and prescription-drug coverage, previously uninsured adults with these conditions reported more doctor visits (13% relative difference, P=0.04), more hospitalizations (20% relative difference, P=0.04), and higher total medical expenditures (51% relative difference, P=0.09) from ages 65 to 72 years than did previously insured adults.
  
  
  CONCLUSIONS
  The costs of expanding health insurance coverage for uninsured adults before they reach the age of 65 years may be partially offset by subsequent reductions in health care use and spending for these adults after the age of 65, particularly if they have cardiovascular disease or diabetes before the age of 65 years.
authors.affiliation: Division of General Medicine and Primary Care, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: J Michael
authors.initials: JM
authors.lastname: McWilliams
authors.forename: Ellen
authors.initials: E
authors.lastname: Meara
authors.forename: Alan M
authors.initials: AM
authors.lastname: Zaslavsky
authors.forename: John Z
authors.initials: JZ
authors.lastname: Ayanian
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases; D003920:Diabetes Mellitus; D005260:Female; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006296:Health Services / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007348:Insurance, Health; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D017057:Medically Uninsured; D006278:Medicare; D008875:Middle Aged; D012959:Socioeconomic Factors; D014481:United States