title: Effect of expanding medicaid for parents on children's health insurance coverage: lessons from the Oregon experiment.
abstract: OBJECTIVE
  In the United States, health insurance is not universal. Observational studies show an association between uninsured parents and children. This association persisted even after expansions in child-only public health insurance. Oregon's randomized Medicaid expansion for adults, known as the Oregon Experiment, created a rare opportunity to assess causality between parent and child coverage.
  
  
  OBJECTIVE
  To estimate the effect on a child's health insurance coverage status when (1) a parent randomly gains access to health insurance and (2) a parent obtains coverage.
  
  
  METHODS
  Oregon Experiment randomized natural experiment assessing the results of Oregon's 2008 Medicaid expansion. We used generalized estimating equation models to examine the longitudinal effect of a parent randomly selected to apply for Medicaid on their child's Medicaid or Children's Health Insurance Program (CHIP) coverage (intent-to-treat analyses). We used per-protocol analyses to understand the impact on children's coverage when a parent was randomly selected to apply for and obtained Medicaid. Participants included 14409 children aged 2 to 18 years whose parents participated in the Oregon Experiment.
  
  
  METHODS
  For intent-to-treat analyses, the date a parent was selected to apply for Medicaid was considered the date the child was exposed to the intervention. In per-protocol analyses, exposure was defined as whether a selected parent obtained Medicaid.
  
  
  METHODS
  Children's Medicaid or CHIP coverage, assessed monthly and in 6-month intervals relative to their parent's selection date.
  
  
  RESULTS
  In the immediate period after selection, children whose parents were selected to apply significantly increased from 3830 (61.4%) to 4152 (66.6%) compared with a nonsignificant change from 5049 (61.8%) to 5044 (61.7%) for children whose parents were not selected to apply. Children whose parents were randomly selected to apply for Medicaid had 18% higher odds of being covered in the first 6 months after parent's selection compared with children whose parents were not selected (adjusted odds ratio [AOR]=1.18; 95% CI, 1.10-1.27). The effect remained significant during months 7 to 12 (AOR=1.11; 95% CI, 1.03-1.19); months 13 to 18 showed a positive but not significant effect (AOR=1.07; 95% CI, 0.99-1.14). Children whose parents were selected and obtained coverage had more than double the odds of having coverage compared with children whose parents were not selected and did not gain coverage (AOR=2.37; 95% CI, 2.14-2.64).
  
  
  CONCLUSIONS
  Children's odds of having Medicaid or CHIP coverage increased when their parents were randomly selected to apply for Medicaid. Children whose parents were selected and subsequently obtained coverage benefited most. This study demonstrates a causal link between parents' access to Medicaid coverage and their children's coverage.
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland2OCHIN, Inc, Portland, Oregon.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: DeVoe
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland.
authors.forename: Miguel
authors.initials: M
authors.lastname: Marino
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland.
authors.forename: Heather
authors.initials: H
authors.lastname: Angier
authors.affiliation: Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland.
authors.forename: Jean P
authors.initials: JP
authors.lastname: O'Malley
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland.
authors.forename: Courtney
authors.initials: C
authors.lastname: Crawford
authors.affiliation: OCHIN, Inc, Portland, Oregon.
authors.forename: Christine
authors.initials: C
authors.lastname: Nelson
authors.affiliation: Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland.
authors.forename: Carrie J
authors.initials: CJ
authors.lastname: Tillotson
authors.affiliation: Department of Family Medicine, Oregon Health & Science University, Portland.
authors.forename: Steffani R
authors.initials: SR
authors.lastname: Bailey
authors.affiliation: Office of Health Analytics, Oregon Health Authority, Portland.
authors.forename: Charles
authors.initials: C
authors.lastname: Gallia
authors.affiliation: OCHIN, Inc, Portland, Oregon5Kaiser Permanente Center for Health Research, Portland, Oregon.
authors.forename: Rachel
authors.initials: R
authors.lastname: Gold
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002669:Child Welfare / Q000191:economics; D002675:Child, Preschool; D005260:Female; D006297:Health Services Accessibility / Q000191:economics; D006801:Humans; D019458:Insurance Coverage / Q000706:statistics & numerical data; D007348:Insurance, Health / Q000706:statistics & numerical data*; D008297:Male; D008484:Medicaid / Q000706:statistics & numerical data*; D009922:Oregon; D010290:Parents; D011897:Random Allocation; D012959:Socioeconomic Factors; D014481:United States