title: Effect of insurance parity on substance abuse treatment.
abstract: OBJECTIVE
  This study examined the impact of insurance parity on the use, cost, and quality of substance abuse treatment.
  
  
  METHODS
  The authors compared substance abuse treatment spending and utilization from 1999 to 2002 for continuously enrolled beneficiaries covered by Federal Employees Health Benefit (FEHB) plans, which require parity coverage of mental health and substance use disorders, with spending and utilization among beneficiaries in a matched set of health plans without parity coverage. Logistic regression models estimated the probability of any substance abuse service use. Conditional on use, linear models estimated total and out-of-pocket spending. Logistic regression models for three quality indicators for substance abuse treatment were also estimated: identification of adult enrollees with a new substance abuse diagnosis, treatment initiation, and treatment engagement. Difference-in-difference estimates were computed as (postparity - preparity) differences in outcomes in plans without parity subtracted from those in FEHB plans.
  
  
  RESULTS
  There were no significant differences between FEHB and non-FEHB plans in rates of change in average utilization of substance abuse services. Conditional on service utilization, the rate of substance abuse treatment out-of-pocket spending declined significantly in the FEHB plans compared with the non-FEHB plans (mean difference=-$101.09, 95% confidence interval [CI]=-$198.06 to -$4.12), whereas changes in total plan spending per user did not differ significantly. With parity, more patients had new diagnoses of a substance use disorder (difference-in-difference risk=.10%, CI=.02% to .19%). No statistically significant differences were found for rates of initiation and engagement in substance abuse treatment.
  
  
  CONCLUSIONS
  Findings suggest that for continuously enrolled populations, providing parity of substance abuse treatment coverage improved insurance protection but had little impact on utilization, costs for plans, or quality of care.
authors.affiliation: Department of Health Care Policy, Harvard Medical School, 180 Longwood Ave., Boston, MA 02115, USA. azzone@hcp.med.harvard.edu
authors.forename: Vanessa
authors.initials: V
authors.lastname: Azzone
authors.forename: Richard G
authors.initials: RG
authors.lastname: Frank
authors.forename: Sharon-Lise T
authors.initials: SL
authors.lastname: Normand
authors.forename: M Audrey
authors.initials: MA
authors.lastname: Burnam
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005382:Financing, Personal / Q000191:economics / Q000706:statistics & numerical data; D054625:Healthcare Disparities / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009310:National Health Insurance, United States / Q000191:economics / Q000331:legislation & jurisprudence / Q000706:statistics & numerical data; D011787:Quality of Health Care / Q000191:economics / Q000706:statistics & numerical data; D019966:Substance-Related Disorders / Q000191:economics / Q000628:therapy*; D014481:United States; D055815:Young Adult