title: The effect of area HMO market share on cancer screening.
abstract: OBJECTIVE
  Managed care may have widespread impacts on health care delivery for all patients in the areas where they operate. We examine the relationship between area managed care activity and screening for breast, cervical, and prostate cancer among patients enrolled in more managed care plans and patients who are enrolled in less managed plans.
  
  
  METHODS
  Data on cancer screening from the 1996 Medical Expenditure Panel Survey (MEPS) were linked to data on health maintenance organization (HMO) and preferred provider organization (PPO) market share and HMO competition at the metropolitan statistical area (MSA) level. Logistic regression analysis was used to examine the relationship between area managed care prevalence and the use of mammography, clinical breast examination, Pap smear, and prostate cancer screening in the past two years, controlling for important covariates.
  
  
  RESULTS
  Among all patients, increases in area-level HMO market share are associated with increases in the appropriate use of mammography, clinical breast exam, and Pap smear (OR for high relative to low managed care areas are 1.75, p < .01, for mammography, 1.58, p < .05, for clinical breast exam, and 1.71, p < .01, for Pap smear). In analyses of subgroups, the relationship is significant only for individuals who are enrolled in the nonmanaged plans; there is no relationship for individuals in more managed plans. No relationship is observed between area HMO market share and prostate cancer screening in any analysis. Neither the level of competition between area HMOs nor area PPO market share is associated with screening rates.
  
  
  CONCLUSIONS
  Area-level managed care activity can influence preventive care treatment patterns.
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Laurence C
authors.initials: LC
authors.lastname: Baker
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Phillips
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Haas
authors.forename: Su-Ying
authors.initials: SY
authors.lastname: Liang
authors.forename: Dean
authors.initials: D
authors.lastname: Sonneborn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis; D005260:Female; D019981:Health Care Sector; D006801:Humans; D008297:Male; D008327:Mammography / Q000706:statistics & numerical data; D008329:Managed Care Programs / Q000191:economics*; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis*; D065006:Papanicolaou Test; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012959:Socioeconomic Factors; D014481:United States; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis; D014626:Vaginal Smears / Q000706:statistics & numerical data