title: Does medical insurance type (private vs public) influence the physician's decision to perform Caesarean delivery?
abstract: BACKGROUND
  US data reveal a Caesarean rate discrepancy between insured and uninsured patients, with the C-section rate highest among the privately insured. The data have prompted concern that financial incentives associated with insurance status might influence American physicians' decisions to perform Caesarean deliveries.
  
  
  OBJECTIVE
  To determine whether differences in medical risk factors account for the apparent Caesarean rate discrepancy between Medicaid and privately insured patients in Michigan, USA.
  
  
  METHODS
  A retrospective review was performed of 617 269 live birth deliveries in Michigan hospitals during 2004-8. All live birth records that were able to be linked to their mothers' hospital discharge records were utilised. Diagnosis-related group codes from the hospitalisation records were used to identify Caesarean deliveries. Regression models determined Caesarean probability for the time period under study, adjusted for insurance type, maternal age, race, maternal medical conditions, multiple births, prematurity and birth weight.
  
  
  RESULTS
  From 2004 to 2008, Caesarean rates were 33% for privately insured patients and 29% for Medicaid patients. The probability of Caesarean delivery was significantly greater for privately insured than Medicaid patients on univariate analysis (OR 1.2, 95% CI 1.19 to 1.22) but not on multivariate analysis (adjusted OR 1.01, 95% CI 0.99 to 1.02).
  
  
  CONCLUSIONS
  No significant disparity was found in the odds of Caesarean delivery between privately insured and Medicaid patients in Michigan after adjusting for other Caesarean risk factors. A positive disparity would have provided de facto evidence that financial incentives play a role in physician decision-making regarding Caesarean delivery.
authors.affiliation: Department of Epidemiology, Michigan State University, East Lansing, MI 48824, USA. tmovsas@epi.msu.edu
authors.forename: Tammy Z
authors.initials: TZ
authors.lastname: Movsas
authors.forename: Eden
authors.initials: E
authors.lastname: Wells
authors.forename: Ann
authors.initials: A
authors.lastname: Mongoven
authors.forename: Violanda
authors.initials: V
authors.lastname: Grigorescu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002585:Cesarean Section / Q000191:economics / Q000706:statistics & numerical data*; D002755:Choice Behavior / Q000941:ethics*; D003657:Decision Making / Q000941:ethics; D003953:Diagnosis-Related Groups / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D019458:Insurance Coverage / Q000191:economics / Q000706:statistics & numerical data*; D007348:Insurance, Health / Q000191:economics / Q000706:statistics & numerical data*; D008484:Medicaid / Q000191:economics / Q000706:statistics & numerical data*; D017057:Medically Uninsured / Q000706:statistics & numerical data; D008824:Michigan / Q000453:epidemiology; D016017:Odds Ratio; D010818:Practice Patterns, Physicians' / Q000191:economics* / Q000941:ethics; D011247:Pregnancy; D017149:Private Sector / Q000706:statistics & numerical data*; D017150:Public Sector / Q000706:statistics & numerical data*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States