MODELING THE COST-EFFECTIVENESS OF OPIOID AGONIST TREATMENT POLICY ALTERNATIVES IN CALIFORNIA'S PUBLICLY-FUNDED DRUG TREATMENT FACILITIES

Purpose: California treats the largest population of individuals with opioid use disorders in the USA and is among a small group of states that applies regulations for opioid agonist treatment (OAT) that are more stringent than existing federal regulations. We assessed the cost-effectiveness of the current standard of OAT in California, which includes mandated short-term (21 day) detoxification for OAT-naïve clients, compared to a scenario in which all entrants access non-time-limited (or maintenance-oriented) OAT.

Method: Our semi-Markov model captures the chronic, recurrent nature of opioid dependence, capturing periods of treatment, incarceration (defined as time spent in jail or prison), relapse (defined by opioid use outside of treatment), opioid abstinence and death. Hypothetical cohorts of prescription opioid (PO) and heroin users entered the model in either detoxification or maintenance treatment with the latter available in both strategies in subsequent treatment attempts. We used linked state-wide administrative data on drug treatment, criminal justice and incarceration, supplemented with other published data, to populate our model. We allowed for subsequent episodes of treatment and relapse to differ in duration, controlling for individuals being under legal supervision (parole or probation) or not. We compared an ‘actual practice’ scenario based on the observed distribution of PO and heroin users across detoxification and maintenance at first treatment to the hypothetical scenario of all treatment entrants initiating maintenance. One-way and probabilistic sensitivity analyses were executed for a range of alternate scenarios.

Result: Allowing access to maintenance-oriented treatment to OAT-naïve individuals was found to be a dominant strategy at 1-year, 5-year and lifetime horizons, resulting in lower total costs and higher quality-adjusted life-year (QALY) gains. Over a lifetime horizon, individuals who initiated maintenance upon first treatment entry gained 13.0 discounted QALYs on average (vs 12.1 for those receiving the standard of care) and generated a societal cost of $0.74 million (vs $1.02 million). Cost savings in the maintenance initiation cohort were realized primarily because of greater treatment retention and the lower costs of criminality associated with the reduced time spent out-of-treatment.

Conclusion: Synthesizing population-level data on OAT in publicly-funded drug treatment facilities in California, we found that immediate access to maintenance treatment may be more effective and less costly than the current standard of care for individuals presenting for opioid use disorder treatment.

Funding: NIDA R01DA031727;R01DA032551;P30DA016383 (PI:Hser)