title: Estimating State Transitions for Opioid Use Disorders.
abstract: The aim was to estimate transitions between periods in and out of treatment, incarceration, and legal supervision, for prescription opioid (PO) and heroin users.
  
  
  
  We captured all individuals admitted for the first time for publicly funded treatment for opioid use disorder (OUD) in California (2006 to 2010) with linked mortality and criminal justice data. We used Cox proportional hazards and competing risks models to assess the effect of primary PO use (v. heroin) on the hazard of transitioning among 5 states: (1) opioid detoxification treatment; (2) opioid agonist treatment (OAT); (3) legal supervision (probation or parole); (4) incarceration (jail or prison); and (5) out-of-treatment. Transitions were conditional on survival, and death was modeled as an absorbing state.
  
  
  
  Both primary PO (n = 11,733) and heroin (n = 19,926) users spent most of their median 2.3 y of observation out of treatment. Primary PO users were significantly younger (median age 30 v. 34 y), and a higher percentage were female (43.1% v. 31.5%; P < 0.001), white (74.6% v. 63.1%; P < 0.001), and had completed high school (31.8% v. 18.9%; P < 0.001). When compared to primary heroin users, PO users had a higher hazard of transitioning from detoxification to OAT (Hazard Ratio (HR), 1.65; 95% CI, 1.54 to 1.77), and had a lower hazard of transitioning from out-of-treatment to either detoxification (0.75 [0.70, 0.81]) or OAT (0.90 [0.85, 0.96]).
  
  
  
  Our findings can be applied directly in state transition modeling to improve the validity of health economic evaluations. Although PO users tended to remain in treatment for longer durations than heroin users, they also tended to remain out of treatment for longer after transitioning to an out-of-treatment state. Despite the proven effectiveness of time-unlimited treatment, individuals with OUD spend most of their time out of treatment.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS (EK, JEM, TK, BN).
authors.forename: Emanuel
authors.initials: E
authors.lastname: Krebs
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS (EK, JEM, TK, BN).
authors.forename: Jeong E
authors.initials: JE
authors.lastname: Min
authors.affiliation: UCLA Integrated Substance Abuse Programs (EE, LL, DH, DU, YH).
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Evans
authors.affiliation: UCLA Integrated Substance Abuse Programs (EE, LL, DH, DU, YH).
authors.forename: Libo
authors.initials: L
authors.lastname: Li
authors.affiliation: Northwestern University Feinberg School of Medicine (LL).
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: UCLA Integrated Substance Abuse Programs (EE, LL, DH, DU, YH).
authors.forename: David
authors.initials: D
authors.lastname: Huang
authors.affiliation: UCLA Integrated Substance Abuse Programs (EE, LL, DH, DU, YH).
authors.forename: Darren
authors.initials: D
authors.lastname: Urada
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS (EK, JEM, TK, BN).|Division of AIDS, Faculty of Medicine, University of British Columbia (TK).
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.affiliation: UCLA Integrated Substance Abuse Programs (EE, LL, DH, DU, YH).
authors.forename: Yih-Ing
authors.initials: YI
authors.lastname: Hser
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS (EK, JEM, TK, BN).|Faculty of Health Sciences, Simon Fraser University (BN).
authors.forename: Bohdan
authors.initials: B
authors.lastname: Nosyk
mesh_terms: D000328:Adult; D002140:California; D005260:Female; D006801:Humans; D008297:Male; D009293:Opioid-Related Disorders / Q000503:physiopathology* / Q000534:rehabilitation; D012189:Retrospective Studies
keywords: criminal justice; heroin; opioid use disorder treatment; prescription opioids; state transitions; subdistribution hazard model