title: Medicaid expansion initiative in Massachusetts: enrollment among substance-abusing homeless adults.
abstract: OBJECTIVE
  We assessed whether homeless adults entering substance abuse treatment in Massachusetts were less likely than others to enroll in Medicaid after implementation of the MassHealth Medicaid expansion program in 1997.
  
  
  METHODS
  We used interrupted time-series analysis in data on substance abuse treatment admissions from the Treatment 0Episode Data Set (1992-2009) to evaluate Medicaid coverage rates in Massachusetts and to identify whether trends differed between homeless and housed participants. We also compared Massachusetts data with data from 17 other states and the District of Columbia combined.
  
  
  RESULTS
  The percentage of both homeless and housed people entering treatment with Medicaid increased approximately 21% after expansion (P = .01), with an average increase of 5.4% per year over 12 years (P = .01). The increase in coverage was specific to Massachusetts, providing evidence that the MassHealth policy was the cause of this increase.
  
  
  CONCLUSIONS
  Findings provide evidence in favor of state participation in the Medicaid expansion in January 2014 under the Affordable Care Act and suggest that hard-to-reach vulnerable groups such as substance-abusing homeless adults are as likely as other population groups to benefit from this policy.
authors.affiliation: At the time of the study, Julia Zur and Ramin Mojtabai were with the Department of Mental Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD.
authors.forename: Julia
authors.initials: J
authors.lastname: Zur
authors.forename: Ramin
authors.initials: R
authors.lastname: Mojtabai
mesh_terms: D000293:Adolescent; D000328:Adult; D006291:Health Policy; D006703:Ill-Housed Persons / Q000706:statistics & numerical data*; D006801:Humans; D008404:Massachusetts; D008484:Medicaid / Q000706:statistics & numerical data* / Q000639:trends; D010343:Patient Admission / Q000706:statistics & numerical data* / Q000639:trends; D016320:Substance Abuse Treatment Centers / Q000706:statistics & numerical data*; D014481:United States; D055815:Young Adult
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