title: On being new to an insurance plan: health care use associated with the first years in a health insurance plan.
abstract: BACKGROUND
  We wanted to compare health care utilization and costs in the first year of being in a health insurance plan with those of subsequent years.
  
  
  METHODS
  We used claims data from an independent practitioner association (IPA)-style managed care organization in the Rochester, NY, metropolitan area from 1996 through 1999. Cross-sectional and panel analyses of up to 4 years of claims data were conducted, involving 335,547 adult patients assigned to the panels of 687 primary care physicians (internists and family physicians). Multivariate analyses, adjusting for age, sex, case mix, and socioeconomic status derived from ZIP codes, examined the relationship between the first year of health insurance and Papanicolaou tests, mammograms in women older than 40 years, physician use, avoidable hospitalization, and expenditures.
  
  
  RESULTS
  After multivariate adjustment, the first year of insurance was associated with a higher risk of not getting a mammogram, a higher risk of avoidable hospitalization, greater likelihood of visiting a physician, and higher expenditures, especially for testing. There was no relationship, however, between Papanicolaou test compliance and year of enrollment.
  
  
  CONCLUSIONS
  The findings suggest there might be adverse clinical and financial implications associated with changing insurance.
authors.affiliation: Center for Health Services Research in Primary Care and Department of Family and Community Medicine, University of California, Davis, Sacramento, Calif 95817, USA. pfranks@ucdavis.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Franks
authors.forename: Colin
authors.initials: C
authors.lastname: Cameron
authors.forename: Klea D
authors.initials: KD
authors.lastname: Bertakis
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data*; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006297:Health Services Accessibility / Q000191:economics; D006302:Health Services Research; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007193:Independent Practice Associations / Q000191:economics* / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009518:New York; D009819:Office Visits; D011314:Preventive Health Services / Q000706:statistics & numerical data; D011320:Primary Health Care / Q000706:statistics & numerical data; D012044:Regression Analysis; D012307:Risk Factors; D013997:Time Factors; D014600:Utilization Review / Q000191:economics*