Benefits and costs of methadone treatment: results from a lifetime simulation model

A Systematic Review of Simulation Models to Track and Address the Opioid Crisis

The opioid overdose crisis is driven by an intersecting set of social, structural, and economic forces. Simulation models offer a tool to help us understand and address this complex, dynamic, and nonlinear social phenomenon. We conducted a systematic review of the literature on simulation models of opioid use and overdose up to September 2019. We extracted modeling types, target populations, interventions, and findings. Further, we created a database of model parameters used for model calibration, and evaluated study transparency and reproducibility. Of the 1,398 articles screened, we identified 88 eligible articles. The most frequent types of models were compartmental (36%), Markov (20%), system dynamics (16%), and Agent-Based models (16%). Over a third evaluated intervention cost-effectiveness (40%), and another third (39%) focused on treatment and harm reduction services for people with opioid use disorder (OUD). More than half (61%) discussed calibrating their models to empirical data, and 31% discussed validation approaches used in their modeling process. From the 63 studies that provided model parameters, we extracted the data sources on opioid use, OUD, OUD treatment, cessation/relapse, emergency medical services, and mortality parameters. This database offers a tool that future modelers can use to identify potential model inputs and evaluate comparability of their models to prior work. Future applications of simulation models to this field should actively tackle key methodological challenges, including the potential for bias in the choice of parameter inputs, investment in model calibration and validation, and transparency in the assumptions and mechanics of simulation models to facilitate reproducibility.

Economic Evaluation in Opioid Modeling: Systematic Review

OBJECTIVES

The rapid increase in opioid overdose and opioid use disorder (OUD) over the past 20 years is a complex problem associated with significant economic costs for healthcare systems and society. Simulation models have been developed to capture and identify ways to manage this complexity and to evaluate the potential costs of different strategies to reduce overdoses and OUD. A review of simulation-based economic evaluations is warranted to fully characterize this set of literature.

METHODS

A systematic review of simulation-based economic evaluation (SBEE) studies in opioid research was initiated by searches in PubMed, EMBASE, and EbscoHOST. Extraction of a predefined set of items and a quality assessment were performed for each study.

RESULTS

The screening process resulted in 23 SBEE studies ranging by year of publication from 1999 to 2019. Methodological quality of the cost analyses was moderately high. The most frequently evaluated strategies were methadone and buprenorphine maintenance treatments; the only harm reduction strategy explored was naloxone distribution. These strategies were consistently found to be cost-effective, especially naloxone distribution and methadone maintenance. Prevention strategies were limited to abuse-deterrent opioid formulations. Less than half (39%) of analyses adopted a societal perspective in their estimation of costs and effects from an opioid-related intervention. Prevention strategies and studies' accounting for patient and physician preference, changing costs, or result stratification were largely ignored in these SBEEs.

CONCLUSION

The review shows consistently favorable cost analysis findings for naloxone distribution strategies and opioid agonist treatments and identifies major gaps for future research.

Economic Evaluation of Interventions to Address Opioid Misuse: A Systematic Review of Methods Used in Simulation Modeling Studies

OBJECTIVES

Several evidence-based interventions exist for people who misuse opioids, but there is limited guidance on optimal intervention selection. Economic evaluations using simulation modeling can guide the allocation of resources and help tackle the opioid crisis. This study reviews methods employed by economic evaluations using computer simulations to investigate the health and economic effects of interventions meant to address opioid misuse.

METHODS

We conducted a systematic mapping review of studies that used simulation modeling to support the economic evaluation of interventions targeting prevention, treatment, or management of opioid misuse or its direct consequences (ie, overdose). We searched 6 databases and extracted information on study population, interventions, costs, outcomes, and economic analysis and modeling approaches.

RESULTS

Eighteen studies met the inclusion criteria. All of the studies considered only one segment of the continuum of care. Of the studies, 13 evaluated medications for opioid use disorder, and 5 evaluated naloxone distribution programs to reduce overdose deaths. Most studies estimated incremental cost per quality-adjusted life-years and used health system and/or societal perspectives. Models were decision trees (n = 4), Markov (n = 10) or semi-Markov models (n = 3), and microsimulations (n = 1). All of the studies assessed parameter uncertainty though deterministic and/or probabilistic sensitivity analysis, 4 conducted formal calibration, only 2 assessed structural uncertainty, and only 1 conducted expected value of information analyses. Only 10 studies conducted validation.

CONCLUSIONS

Future economic evaluations should consider synergies between interventions and examine combinations of interventions to inform optimal policy response. They should also more consistently conduct model validation and assess the value of further research.

Change in alcohol and other drug use during five years of continuous opioid substitution treatment

BACKGROUND

English national prospective, observational cohort study of patients continuously enrolled for five years in opioid substitution treatment (OST) with oral methadone and sublingual buprenorphine. This is a secondary outcome analysis of change in use of alcohol and other drug use (AOD) following identification of heroin use trajectories during OST.

METHODS

All adults admitted to community OST in 2008/09 and enrolled to 2013/14 (n = 7717). Data from 11 sequential, six-monthly clinical reviews were used to identify heroin and AOD use trajectories by multi-level Latent Class Growth Analysis. OST outcome in the sixth and seventh year was 'successful completion and no re-presentation' (SCNR) to structured treatment and was assessed using multi-level logistic regression.

RESULTS

With 'rapid decreasing' heroin use trajectory as referent, 'continued high-level' heroin use predicted 'continued high-level' crack cocaine use (relative risk ratio [RRR] 58.7; 95% confidence interval [CI] 34.2-100.5),'continued high-level' alcohol use (RRR 1.2; 95% CI 1.0-1.5), 'increasing' unspecified drug use (RRR 1.7; 95% CI 1.4-2.1) and less 'high and increasing' cannabis use (RRR 0.5; 95% CI 0.4-0.6). 'Increasing' crack use was negatively associated with SCNR outcome for the 'decreasing then increasing' and 'gradual decreasing' heroin use groups (adjusted odds ratio [AOR] 0.5; 95% CI 0.3-0.9 and AOR 0.2; 95% CI 0.1-0.7, respectively).

CONCLUSIONS

Continued high-level heroin use non-response during long-term OST is associated with high-level crack cocaine and alcohol use, increasing unspecified drug use, but less high and increasing cannabis use. Increasing use of crack cocaine is negatively associated with the likelihood that long-term OST is completed successfully.

The costs of crime associated with stimulant use in a Canadian setting

BACKGROUND

Costs attributable to criminal activity are a major component of the economic burden of substance use disorders, yet there is a paucity of empirical evidence on this topic. Our aim was to estimate the costs of crime associated with different forms and intensities of stimulant use.

METHODS

Retrospective cohort study, including individuals from three prospective cohorts in Vancouver, Canada, measured biannually (2011-2015), reporting stimulant use at baseline assessment. Monthly crime costs included policing, court, corrections, and criminal victimization (2016 CAD). We estimated monthly crime costs associated with mutually exclusive categories of crack, cocaine, methamphetamine, and polystimulant use, stratified by daily/non-daily use, relative to stimulant abstinence, as well as the independent effects of treatment (opioid agonist (OAT) and other addiction treatment). We used a two-part model, capturing the probability of criminal activity and costs of crime with generalized linear logistic and gamma regression models, respectively, controlling for age, gender, education, homelessness, mental health issues, employment, prior incarceration, alcohol and opioid use.

RESULTS

The study sample included 1599 individuals (median age 39, 65.9% male) assessed over 5299 biannual interviews. Estimates of associated monthly crime costs ranged from $5449 [95% C.I.: $2180, $8719] for non-daily polystimulant use, to $8893 [$4196, $13,589] for daily polystimulant use. Cost differences between daily/non-daily use, injection/non-injection, and stimulant type were not statistically significant. Drug treatment was not associated with lower monthly crime costs in our sample.

CONCLUSIONS

Substantial crime-related costs were associated with stimulant use, emphasizing the urgency for development and implementation of efficacious treatment regimens.

Estimating State Transitions for Opioid Use Disorders

AIM

The aim was to estimate transitions between periods in and out of treatment, incarceration, and legal supervision, for prescription opioid (PO) and heroin users.

METHODS

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.

RESULTS

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]).

CONCLUSION

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.

Opioid Use Disorder in Pregnancy: Health Policy and Practice in the Midst of an Epidemic

Opioid abuse among pregnant women has reached epidemic proportions and has influenced maternal and child health policy at the federal, state, and local levels. As a result, we review the current state of opioid use in pregnancy and evaluate recent legislative and health policy initiatives designed to combat opioid addiction in pregnancy. We emphasize the importance of safe and responsible opioid-prescribing practices, expanding the availability and accessibility of medication-assisted treatment and standardizing care for neonates at risk of neonatal abstinence syndrome. Efforts to penalize pregnant women and negative consequences for disclosing substance use to health care providers are harmful and may prevent women from seeking prenatal care and other beneficial health care services during pregnancy. Instead, health care providers should advocate for health policy informed by scientific research and evidence-based practice to reduce the burden of prenatal opioid abuse and optimize outcomes for mothers and their neonates.

A systematic review of health economic models of opioid agonist therapies in maintenance treatment of non-prescription opioid dependence

BACKGROUND

Opioid dependence is a chronic condition with substantial health, economic and social costs. The study objective was to conduct a systematic review of published health-economic models of opioid agonist therapy for non-prescription opioid dependence, to review the different modelling approaches identified, and to inform future modelling studies.

METHODS

Literature searches were conducted in March 2015 in eight electronic databases, supplemented by hand-searching reference lists and searches on six National Health Technology Assessment Agency websites. Studies were included if they: investigated populations that were dependent on non-prescription opioids and were receiving opioid agonist or maintenance therapy; compared any pharmacological maintenance intervention with any other maintenance regimen (including placebo or no treatment); and were health-economic models of any type.

RESULTS

A total of 18 unique models were included. These used a range of modelling approaches, including Markov models (n = 4), decision tree with Monte Carlo simulations (n = 3), decision analysis (n = 3), dynamic transmission models (n = 3), decision tree (n = 1), cohort simulation (n = 1), Bayesian (n = 1), and Monte Carlo simulations (n = 2). Time horizons ranged from 6 months to lifetime. The most common evaluation was cost-utility analysis reporting cost per quality-adjusted life-year (n = 11), followed by cost-effectiveness analysis (n = 4), budget-impact analysis/cost comparison (n = 2) and cost-benefit analysis (n = 1). Most studies took the healthcare provider's perspective. Only a few models included some wider societal costs, such as productivity loss or costs of drug-related crime, disorder and antisocial behaviour. Costs to individuals and impacts on family and social networks were not included in any model.

CONCLUSION

A relatively small number of studies of varying quality were found. Strengths and weaknesses relating to model structure, inputs and approach were identified across all the studies. There was no indication of a single standard emerging as a preferred approach. Most studies omitted societal costs, an important issue since the implications of drug abuse extend widely beyond healthcare services. Nevertheless, elements from previous models could together form a framework for future economic evaluations in opioid agonist therapy including all relevant costs and outcomes. This could more adequately support decision-making and policy development for treatment of non-prescription opioid dependence.

A systematic review of modelling approaches in economic evaluations of health interventions for drug and alcohol problems

Background

The overarching goal of health policies is to maximize health and societal benefits. Economic evaluations can play a vital role in assessing whether or not such benefits occur. This paper reviews the application of modelling techniques in economic evaluations of drug and alcohol interventions with regard to (i) modelling paradigms themselves; (ii) perspectives of costs and benefits and (iii) time frame.

Methods

Papers that use modelling approaches for economic evaluations of drug and alcohol interventions were identified by carrying out searches of major databases.

Results

Thirty eight papers met the inclusion criteria. Overall, the cohort Markov models remain the most popular approach, followed by decision trees, Individual based model and System dynamics model (SD). Most of the papers adopted a long term time frame to reflect the long term costs and benefits of health interventions. However, it was fairly common among the reviewed papers to adopt a narrow perspective that only takes into account costs and benefits borne by the health care sector.

Conclusions

This review paper informs policy makers about the availability of modelling techniques that can be used to enhance the quality of economic evaluations for drug and alcohol treatment interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1368-8) contains supplementary material, which is available to authorized users.

The causal effect of opioid substitution treatment on HAART medication refill adherence

BACKGROUND

People who inject drugs (PWID) account for roughly 13% of the prevalent HIV/AIDS population outside of sub-Saharan Africa, and access to opioid substitution treatment (OST) is limited in many settings globally. OST likely facilitates access to HAART, yet sparse evidence is available to support this hypothesis. Our objective was to determine the causal impact of OST exposure on HAART adherence among HIV-positive PWID in a Canadian setting.

METHODS

We executed a retrospective cohort study using linked population-level data for British Columbia, Canada (January 1996-March 2010). We considered HIV-positive PWID after meeting HAART initiation criteria. A marginal structural model was estimated on a monthly timescale using inverse probability of treatment weights. The primary outcome was 95% HAART adherence, according to pharmacy refill compliance. Exposure to OST was defined as 95% of OST receipt, and we controlled for a range of fixed and time-varying covariates.

RESULTS

Our study included 1852 (63.3%) HIV-positive PWID with a median follow-up of 5.5 years; 34% were female and 39% had previously accessed OST. The baseline covariate-adjusted odds of HAART adherence following OST exposure was 1.96 (95% confidence interval: 1.72-2.24), although the adjusted odds estimated within the marginal structural model was 1.68 (1.48-1.92). Findings were robust to sensitivity analyses on model specification.

CONCLUSION

In a setting characterized by universal healthcare and widespread access to both office-based OST and HAART, OST substantially increased the odds of HAART adherence. This underlines the need to address barriers to OST globally to reduce the disease burden of both opioid dependence and HIV/AIDS.

Economic evaluations of contingency management in illicit drug misuse programmes: A systematic review

ISSUES

UK clinical guidelines published in 2007 recommended contingency management (CM) as an adjunct to opiate substitution therapy. However, CM has not been adopted in the UK despite evidence of clinical effectiveness. Evidence for the cost-effectiveness of CM is less clear and will need to be explored if CM is to be adopted by national health systems in countries such as the UK.

APPROACH

Systematic review and descriptive synthesis of published economic evaluations.

KEY FINDINGS

The review identified nine published studies that could be classified as economic evaluations. These were all based within US treatment settings, and five were conducted by the same group of authors. All studies found that the addition of CM to usual care increased both costs and effects (commonly drug abstinence or medication adherence).

IMPLICATIONS

This review confirms that the existing evidence base for cost-effectiveness has limited generalisability beyond the original research clinical settings and populations.

CONCLUSION

The data were not sufficiently strong to make any conclusion about the cost-effectiveness of CM. More relevant and comprehensive evidence for cost-effectiveness than currently exists is needed.

The Cost-effectiveness of Alcohol Screening, Brief Intervention, and Referral to Treatment (SBIRT) in Emergency and Outpatient Medical Settings

OBJECTIVE

This study analyzed the cost-effectiveness of delivering alcohol screening, brief intervention, and referral to treatment (SBIRT) in emergency departments (ED) when compared to outpatient medical settings.

METHODS

A probabilistic decision analytic tree categorized patients into health states. Utility weights and social costs were assigned to each health state. Health outcome measures were the proportion of patients not drinking above threshold levels at follow-up, the proportion of patients transitioning from above threshold levels at baseline to abstinent or below threshold levels at follow-up, and the quality-adjusted life years (QALYs) gained. Expected costs under a provider perspective were the marginal costs of SBIRT, and under a societal perspective were the sum of SBIRT cost per patient and the change in social costs. Incremental cost-effectiveness ratios were computed.

RESULTS

When considering provider costs only, compared to outpatient, SBIRT in ED cost $8.63 less, generated 0.005 more QALYs per patient, and resulted in 13.8% more patients drinking below threshold levels. Sensitivity analyses in which patients were assumed to receive a fixed number of treatment sessions that met clinical sites' guidelines made SBIRT more expensive in ED than outpatient; the ED remained more effective. In this sensitivity analysis, the ED was the most cost-effective setting if decision makers were willing to pay more than $1500 per QALY gained.

CONCLUSIONS

Alcohol SBIRT generates costs savings and improves health in both ED and outpatient settings. EDs provide better effectiveness at a lower cost and greater social cost reductions than outpatient.

Dynamics in the costs of criminality among opioid dependent individuals

BACKGROUND

Research into the avoided crime-related costs associated with methadone maintenance treatment (MMT) is sparse. Our objective was to characterize the dynamics in crime-related costs associated with MMT effectiveness among opioid dependent individuals in Vancouver, Canada.

METHODS

We considered individuals enrolled in a prospective study between December, 2011 and May, 2013. Monthly crime-related costs (2013 CAD) were derived from self-reported criminal activity. On the basis of MMT receipt and illicit opioid use, individuals were classified in mutually exclusive health states: (i) MMT high effectiveness; (ii) MMT low effectiveness; (iii) opioid abstinence; or (iv) relapse. We classified individuals as daily, non-daily or non-stimulant users and controlled for demographic and socio-economic characteristics. A two-part multiple regression model was constructed; the first part modeled non-zero cost probability, the second estimated the level of costs. Avoided costs were estimated for each health state and stratified by stimulant use intensity.

RESULTS

Our study included 982 individuals (median age 47, 38% female) for 2232 observations. Individuals on MMT with high effectiveness incurred lower monthly costs of criminality (avoided costs of $6298; 95% C.I. ($1578, $11,017)), as did opioid abstinent individuals ($6563 ($1564, $11,561)). Avoided costs for daily stimulant users were greater than for non-daily users, both for individuals on MMT with high effectiveness ($12,975 vs. $4125) and opioid abstinent ($12,640 vs. $4814).

CONCLUSION

Using longitudinal data on individuals with a history of MMT, we found substantially lower costs of criminality associated with high effect to MMT. Avoided costs were highest among daily stimulant users that were on MMT with high effectiveness or those opioid abstinent.

Utilization and outcomes of detoxification and maintenance treatment for opioid dependence in publicly-funded facilities in California, USA: 1991-2012

BACKGROUND

California treats the largest population of opioid dependent individuals in the USA and is among a small group of states that applies regulations for opioid treatment that are more stringent than existing federal regulations. We aim to characterize changes in patient characteristics and treatment utilization over time, and identify determinants of successful completion of detoxification and MMT retention in repeated attempts.

METHODS

State-wide administrative data was obtained from California Outcome Measurement System during the period: January 1st, 1991-March 31st, 2012. Short-term detoxification treatment and long-term maintenance treatment, primarily with methadone, was available to study participants. Mixed effects regression models were used to define determinants of successful completion of the detoxification treatment protocol (as classified by treatment staff) and duration of maintenance treatment.

RESULTS

The study sample consisted of 237,709 unique individuals and 885,971 treatment episodes; 837% were detoxification treatment episodes in 1994, dropping to 40.5% in 2010. Among individuals accessing only detoxification, the adjusted odds of success declined with each successive attempt (vs. 1st attempt: 2nd: OR: 0.679; 95% CI (0.610, 0.755); 3rd: 0.557 (0.484, 0.641); 4th: 0.526 (0.445, 0.622); 5th: 0.407 (0.334, 0.497); ≥6th: 0.339 (0.288, 0.399). For those ever accessing maintenance treatment, later subsequent attempts were longer in duration, and those with two or more prior attempts at detoxification had marginally longer subsequent maintenance episodes (hazard ratio: 0.97; 95% CI: 0.95, 0.99). Finally, only 10.9% of all detoxification episodes were followed by admission into maintenance treatment within 14 days.

CONCLUSIONS

This study has revealed high rates of detoxification treatment for opioid dependence in California throughout the study period, and decreasing odds of success in repeated attempts at detoxification.

Characterizing longitudinal health state transitions among heroin, cocaine, and methamphetamine users

AIMS

Characterize longitudinal patterns of drug use careers and identify determinants of drug use frequency across cohorts of primary heroin, methamphetamine (MA) and cocaine users.

DESIGN

Pooled analysis of prospective cohort studies.

SETTINGS

Illicit drug users recruited from community, criminal justice and drug treatment settings in California, USA.

PARTICIPANTS

We used longitudinal data on from five observational cohort studies featuring primary users of heroin (N=629), cocaine (N=694) and methamphetamine (N=474). The mean duration of follow-up was 20.9 years.

MEASUREMENTS

Monthly longitudinal data was arranged according to five health states (incarceration, drug treatment, abstinence, non-daily and daily use). We fitted proportional hazards (PH) frailty models to determine independent differences in successive episode durations. We then executed multi-state Markov (MSM) models to estimate probabilities of transitioning between health states, and the determinants of these transitions.

FINDINGS

Across primary drug use types, PH frailty models demonstrated durations of daily use diminished in successive episodes over time. MSM models revealed primary stimulant users had more erratic longitudinal patterns of drug use, transitioning more rapidly between periods of treatment, abstinence, non-daily and daily use. MA users exhibited relatively longer durations of high-frequency use. Criminal engagement had a destabilizing effect on health state durations across drug types. Longer incarceration histories were associated with delayed transitions toward cessation.

CONCLUSIONS

PH frailty and MSM modeling techniques provided complementary information on longitudinal patterns of drug abuse. This information can inform clinical practice and policy, and otherwise be used in health economic simulation models, designed to inform resource allocation decisions.

A call for evidence-based medical treatment of opioid dependence in the United States and Canada

Despite decades of experience treating heroin or prescription opioid dependence with methadone or buprenorphine--two forms of opioid substitution therapy--gaps remain between current practices and evidence-based standards in both Canada and the United States. This is largely because of regulatory constraints and pervasive suboptimal clinical practices. Fewer than 10 percent of all people dependent on opioids in the United States are receiving substitution treatment, although the proportion may increase with expanded health insurance coverage as a result of the Affordable Care Act. In light of the accumulated evidence, we recommend eliminating restrictions on office-based methadone prescribing in the United States; reducing financial barriers to treatment, such as varying levels of copayment in Canada and the United States; reducing reliance on less effective and potentially unsafe opioid detoxification; and evaluating and creating mechanisms to integrate emerging treatments. Taking these steps can greatly reduce the harms of opioid dependence by maximizing the individual and public health benefits of treatment.

Did we get our money's worth? Bridging economic and behavioral measures of program success in adolescent drug prevention

The recent U.S. Congressional mandate for creating drug-free learning environments in elementary and secondary schools stipulates that education reform rely on accountability, parental and community involvement, local decision making, and use of evidence-based drug prevention programs. By necessity, this charge has been paralleled by increased interest in demonstrating that drug prevention programs net tangible benefits to society. One pressing concern is precisely how to integrate traditional scientific methods of program evaluation with economic measures of “cost efficiency”. The languages and methods of each respective discipline don’t necessarily converge on how to establish the true benefits of drug prevention. This article serves as a primer for conducting economic analyses of school-based drug prevention programs. The article provides the reader with a foundation in the relevant principles, methodologies, and benefits related to conducting economic analysis. Discussion revolves around how economists value the potential costs and benefits, both financial and personal, from implementing school-based drug prevention programs targeting youth. Application of heterogeneous costing methods coupled with widely divergent program evaluation findings influences the feasibility of these techniques and may hinder utilization of these practices. Determination of cost-efficiency should undoubtedly become one of several markers of program success and contribute to the ongoing debate over health policy.

Interim versus standard methadone treatment: a benefit-cost analysis

A benefit-cost analysis was conducted as part of a clinical trial in which newly-admitted methadone patients were randomly assigned to interim methadone (IM; methadone without counseling) for the first 4 months of 12 months of methadone treatment or 12 months of methadone with one of two counseling conditions. Health, residential drug treatment, criminal justice costs, and income data in 2010 dollars were obtained at treatment entry, and 4- and 12-month follow-up from 200 participants and program costs were obtained. The net benefits of treatment were greater for the IM condition but controlling for the baseline variables noted above, the difference between conditions in net monetary benefits was not significant. For the combined sample, there was a pre- to post-treatment net benefit of $1470 (95% CI: -$625; $3584) and a benefit-cost ratio of 1.5 (95% CI: 0.8, 2.3), but using our conservative approach to calculating benefits, these values were not significant.

Offender diversion into substance use disorder treatment: the economic impact of California's proposition 36

OBJECTIVES

We determined the costs and savings attributable to the California Substance Abuse and Crime Prevention Act (SACPA), which mandated probation or continued parole with substance abuse treatment in lieu of incarceration for adult offenders convicted of nonviolent drug offenses and probation and parole violators.

METHODS

We used individually linked, population-level administrative data to define intervention and control cohorts of offenders meeting SACPA eligibility criteria. Using multivariate difference-in-differences analysis, we estimated the effect of SACPA implementation on the total and domain-specific costs to state and county governments, controlling for fixed individual and county characteristics and changes in crime at the county level.

RESULTS

The additional costs of treatment were more than offset by savings in other domains, primarily in the costs of incarceration. We estimated the statewide policy effect as an adjusted savings of $2317 (95% confidence interval = $1905, $2730) per offender over a 30-month postconviction period. SACPA implementation resulted in greater incremental cost savings for Blacks and Hispanics, who had markedly higher rates of conviction and incarceration.

CONCLUSIONS

The monetary benefits to government exceeded the additional costs of SACPA implementation and provision of treatment.

Characterizing durations of heroin abstinence in the California Civil Addict Program: results from a 33-year observational cohort study

In accordance with the chronic disease model of opioid dependence, cessation is often observed as a longitudinal process rather than a discrete endpoint. We aimed to characterize and identify predictors of periods of heroin abstinence in the natural history of recovery from opioid dependence. Data were collected on participants from California who were enrolled in the Civil Addict Program from 1962 onward by use of a natural history interview. Multivariate regression using proportional hazards frailty models was applied to identify independent predictors and correlates of repeated abstinence episode durations. Among 471 heroin-dependent males, 387 (82.2%) reported 932 abstinence episodes, 60.3% of which lasted at least 1 year. Multivariate analysis revealed several important findings. First, demographic factors such as age and ethnicity did not explain variation in durations of abstinence episodes. However, employment and lower drug use severity predicted longer episodes. Second, abstinence durations were longer following sustained treatment versus incarceration. Third, individuals with multiple abstinence episodes remained abstinent for longer durations in successive episodes. Finally, abstinence episodes initiated >10 and ≤20 years after first use lasted longer than others. Public policy facilitating engagement of opioid-dependent individuals in maintenance-oriented drug treatment and employment is recommended to achieve and sustain opioid abstinence.

Methadone treatments in a Swiss region, 2001-2008: a registry-based analysis

BACKGROUND

To determine, in a region of Switzerland, the duration of retention in opioid substitution treatments with methadone (OSTM), duration of treatment interruptions, probability of re-entry to treatment after a treatment interruption, and associated factors.

METHODS

A secondary analysis of registry-based data was performed with patients (n = 2880) registered in the methadone treatment register database of the Public Health Service of the canton of Vaud between January 1, 2001 and June 30, 2008. Survival analysis and multivariate analysis was conducted.

RESULTS

The probability of remaining on treatment was 69% at 1 year and 45% at 3 years (n =1666). One-third of patients remained on treatment beyond 5 years. The estimated hazard of leaving treatment was increased by a ratio of 1.31 in the case of a first treatment (P = 0.001), 1.83 for those without a fixed home (P < 0.001), and 1.29 for those younger than 30 years old (P < 0.001). The probability of having begun a new treatment after a first interruption was 21% at one year, 38% at 3 years, and 43% at 5 years (n = 1581). Factors at the interruption of treatment associated with a higher probability of re-entering were: interruption not due to methadone withdrawal, bad physical health, and higher methadone dose.

CONCLUSIONS

OSTM are long-term (maintenance) treatments in Switzerland. Younger age, bad living conditions at entry, and first treatment are predictors of lower retention. Approximately one-half of patients who interrupt treatment will re-enter treatment within 5 years.

Continuous time simulation and discretized models for cost-effectiveness analysis

The design of decision-analytic models for cost-effectiveness analysis has been the subject of discussion. The current work addresses this issue by noting that, when time is to be explicitly modelled, we need to represent phenomena occurring in continuous time. Models evaluated in continuous time may not have closed-form solutions, and in this case, two approximations can be used: simulation models in continuous time and discretized models at the aggregate level. Stylized examples were set up where both approximations could be implemented. These aimed to illustrate determinants of the use of the two approximations: cycle length and precision, the use of continuity corrections in discretized models and the discretization of rates into probabilities. The examples were also used to explore the impact of the approximations not only in terms of absolute survival but also cost effectiveness and incremental comparisons. Discretized models better approximate continuous time results if lower cycle lengths are used. Continuous time simulation models are inherently stochastic, and the precision of the results is determined by the simulation sample size. The use of continuity corrections in discretized models allows the use of greater cycle lengths, producing no significant bias from the discretization. How the process is discretized (the conversion of rates into probabilities) is key. Results show that appropriate discretization coupled with the use of a continuity correction produces results unbiased for higher cycle lengths. Alternative methods of discretization are less efficient, i.e. lower cycle lengths are needed to obtain unbiased results. The developed work showed the importance of acknowledging bias in estimating cost effectiveness. When the alternative approximations can be applied, we argue that it is preferable to implement a cohort discretized model rather than a simulation model in continuous time. In practice, however, it may not be possible to represent the decision problem by any conventionally defined discretized model, in which case other model designs need to be applied, e.g. a simulation model.

Benefits and costs of substance abuse treatment programs for state prison inmates: results from a lifetime simulation model

Reflecting drug use patterns and criminal justice policies throughout the 1990s and 2000s, prisons hold a disproportionate number of society's drug abusers. Approximately 50% of state prisoners meet the criteria for a diagnosis of drug abuse or dependence, but only 10% receive medically based drug treatment. Because of the link between substance abuse and crime, treating substance abusing and dependent state prisoners while incarcerated has the potential to yield substantial economic benefits. In this paper, we simulate the lifetime costs and benefits of improving prison-based substance abuse treatment and post-release aftercare for a cohort of state prisoners. Our model captures the dynamics of substance abuse as a chronic disease; estimates the benefits of substance abuse treatment over individuals' lifetimes; and tracks the costs of crime and criminal justice costs related to policing, adjudication, and incarceration. We estimate net societal benefits and cost savings to the criminal justice system of the current treatment system and five policy scenarios. We find that four of the five policy scenarios provide positive net societal benefits and cost savings to the criminal justice system relative to the current treatment system. Our study demonstrates the societal gains to improving the drug treatment system for state prisoners.

Clinical implications of drug abuse epidemiology

Research on the epidemiology of illicit drug use disorders provides continued critical insights into the distribution and determinants of drug use and drug use disorders in the United States. This research serves as a foundation for understanding the etiology of these disorders, helping to disentangle the complex interrelationship of developmental, genetic, and environmental risk and protective factors. Building on an understanding of this research in substance abuse epidemiology, it is important for clinicians to understand the unique trends in drug use in the overall communities that they serve and the unique risk factors for given individuals. The generally high prevalence of substance use disorders, along with their high comorbidity with other psychiatric disorders and with the HIV epidemic, make prevention, evaluation, and referral for treatment for drug abuse an important part of routine clinical practice in a range of clinical settings, including primary care, psychiatric, and emergency department settings. Ongoing efforts to ensure insurance coverage parity for the treatment of mental health and substance use disorders offer the promise of continued improvements in the integration and availability of such services in the broader US health care system.

Conducting economic evaluations of screening and brief intervention for hazardous drinking: Methods and evidence to date for informing policy

ISSUES

Many policy review articles have concluded that alcohol screening and brief intervention (SBI) is both cost-effective and cost-beneficial. Yet a recent cost-effectiveness review for the United Kingdom's National Institute for Health and Clinical Excellence suggests that these conclusions may be premature.

APPROACH

This article offers a brief synopsis of the various types of economic analyses that may be applied to SBI, including cost analysis, cost-effectiveness analysis, cost-utility analysis, cost-benefit analysis and other types of economic evaluation. A brief overview of methodological issues is provided, and examples from the SBI evaluation literature are provided.

KEY FINDINGS, IMPLICATIONS AND CONCLUSIONS

The current evidence base is insufficient to draw firm conclusions about the cost, cost-effectiveness or cost-benefit of SBI and about the impact of SBI on health-care utilisation.[Cowell AJ, Bray JW, Mills MJ, Hinde JM. Conducting economic evaluations of screening and brief intervention for hazardous drinking: Methods and evidence to date for informing policy.

The cost of integrated HIV care and buprenorphine/naloxone treatment: results of a cross-site evaluation

BACKGROUND

Implementing integrated HIV and buprenorphine/naloxone treatment requires cost estimates to plan and obtain funding.

METHODS

We identified costs incurred at HIV clinical sites participating in a cross-site evaluation of integrated care that followed patients for 1 year. Costs include labor, overhead, and urine toxicology analyses (clinic perspective), buprenorphine/naloxone (payer perspective) and patient time and transportation (patient perspective). Sites provided resource utilization quarterly, and providers estimated time required for each activity. With site as the unit of analysis, results are reported as median (range) of average site costs in 2008 US dollars.

RESULTS

The median number of monthly provider encounters for integrated care patients was 3.2 (1.5-13.3) compared with 1.7 (1.1-4.2) for similar patients not in integrated care, but integrated care patients had fewer physician encounters. Median monthly clinic costs per integrated care patient were $136 ($67-$677) for labor and overhead and $8 ($2-$23) for toxicology analyses, $22 higher than clinic costs for patients not in integrated care. Median monthly costs for buprenorphine/naloxone were $209 ($165-$272), and monthly patient costs in integrated care were $11 ($1-$54) higher.

CONCLUSIONS

Integrated HIV and buprenorphine/naloxone treatment requires different resources, including costs that are not third-party reimbursed. Implementing integrated care will require funding for training and for new staff such as buprenorphine coordinators, in addition to reimbursement for buprenorphine/naloxone. Further research is needed to identify potential cost offsets outside of the clinic setting.

What are your priorities right now? Identifying service needs across recovery stages to inform service development

Substance use disorders (SUD) are, for many, chronic conditions that are typically associated with severe impairments in multiple areas of functioning. "Recovery" from SUD is, for most, a lengthy process; improvements in other areas of functioning do not necessarily follow the attainment of abstinence. The current SUD service model providing intense, short-term, symptom-focused services is ill-suited to address these issues. A recovery-oriented model of care is emerging, which provides coordinated recovery-support services using a chronic-care model of sustained recovery management. Information is needed about substance users' priorities, particularly persons in recovery who are not currently enrolled in treatment, to guide the development of recovery-oriented systems. As a first step in filling this gap, we present qualitative data on current life priorities among a sample of individuals that collectively represent successive recovery stages (N = 356). Findings suggest that many areas of functioning remain challenging long after abstinence is attained, most notably employment and education, family/social relations, and housing. Although the ranking of priorities changes somewhat across recovery stages, employment is consistently the second most important priority, behind working on one's recovery. Study limitations are noted, and the implications of findings for the development and evaluation of recovery-oriented services are discussed.

The cost-effectiveness of prize-based and voucher-based contingency management in a population of cocaine- or opioid-dependent outpatients

OBJECTIVE

To evaluate the cost-effectiveness of using prize-based and voucher-based contingency management (CM) as additions to standard treatment for cocaine- or heroin-dependent outpatients in community treatment centers.

METHODS

This cost-effectiveness analysis is based on a randomized clinical trial conducted at three community-based outpatient psychosocial substance abuse treatment clinics. A total of 142 cocaine- or heroin-dependent outpatients were randomly assigned to one of three treatment conditions: standard treatment (ST), ST with prizes (prize CM), or ST with vouchers (voucher CM) for 12 weeks. The primary patient outcome was the longest duration of confirmed abstinence (LDA) from cocaine, opioids and alcohol during treatment. Unit costs were collected from the three participating clinics. Resource utilizations and patient outcomes were obtained from the clinical trial. Incremental cost-effectiveness ratios (ICERs) and acceptability curves were used to evaluate the relative cost-effectiveness of the interventions.

RESULTS

Based on the ICERs and acceptability curves, ST is likely to be the most cost-effective intervention when the threshold value to decision makers of lengthening the LDA during treatment by 1 week is less than approximately $166, and prize CM is likely to be the most cost-effective intervention when the threshold value is greater than approximately $166.

CONCLUSIONS

Prize CM was found likely to be the most cost-effective intervention over a comparatively wide range of threshold values for lengthening the LDA during treatment by 1 week. However, additional studies with alternative incentive parameters are required to determine the generalizability of our results.

Treating drug abuse and addiction in the criminal justice system: improving public health and safety

Despite increasing evidence that addiction is a treatable disease of the brain, most individuals do not receive treatment. Involvement in the criminal justice system often results from illegal drug-seeking behavior and participation in illegal activities that reflect, in part, disrupted behavior ensuing from brain changes triggered by repeated drug use. Treating drug-involved offenders provides a unique opportunity to decrease substance abuse and reduce associated criminal behavior. Emerging neuroscience has the potential to transform traditional sanction-oriented public safety approaches by providing new therapeutic strategies against addiction that could be used in the criminal justice system. We summarize relevant neuroscientific findings and evidence-based principles of addiction treatment that, if implemented in the criminal justice system, could help improve public heath and reduce criminal behavior.

Individual and system influences on waiting time for substance abuse treatment

Waiting time is a contemporary reality of many drug abuse treatment programs, resulting in substantial problems for substance users and society. Individual and system factors that influence waiting time are diverse and may vary at different points in the treatment continuum. This study assessed waiting time preceding clinical assessment at a centralized intake unit and during the period after the assessment but before treatment entry. The present study included 577 substance abusers who were enrolled in a large clinical trial of two brief treatment interventions in a midsize metropolitan area in Ohio. Bivariate analyses identified individual and system factors that influenced preassessment and postassessment waiting time, as well as total wait to treatment services. Multivariate analyses demonstrated that longer wait time for an assessment is influenced by being court referred, less belief in having a substance abuse problem, and less desire for change. A shorter wait to actually enter treatment is predicted by having a case manager, being more ready for treatment, and having less severe employment and alcohol problems. The different influences present during the two waiting periods suggest that assessment and treatment programs need to implement system changes and entry enhancement interventions that are specific to the needs of substance abusers at each waiting period.

Employment among chronic drug users at baseline and 6-month follow-up

Most studies of unemployment among chronic drug users (CDUs) are drug-user treatment-based and there is little information on employment/unemployment among CDUs not in treatment. Between June 2003 and September 2004, 492 CDUs in Miami-Dade, Florida, were administered a quantitative survey at baseline and 6 months later; employment status was measured. Descriptive statistics showed that only 15% were employed at both periods, an equal percentage becoming employed and unemployed at 6 months. The majority of CDUs were unemployed at both time periods. Men were more likely than women to exhibit consistent employment over the two time periods. The study's limitations are noted and future research is suggested.

Can discrete event simulation be of use in modelling major depression?

BACKGROUND

Depression is among the major contributors to worldwide disease burden and adequate modelling requires a framework designed to depict real world disease progression as well as its economic implications as closely as possible.

OBJECTIVES

In light of the specific characteristics associated with depression (multiple episodes at varying intervals, impact of disease history on course of illness, sociodemographic factors), our aim was to clarify to what extent "Discrete Event Simulation" (DES) models provide methodological benefits in depicting disease evolution.

METHODS

We conducted a comprehensive review of published Markov models in depression and identified potential limits to their methodology. A model based on DES principles was developed to investigate the benefits and drawbacks of this simulation method compared with Markov modelling techniques.

RESULTS

The major drawback to Markov models is that they may not be suitable to tracking patients' disease history properly, unless the analyst defines multiple health states, which may lead to intractable situations. They are also too rigid to take into consideration multiple patient-specific sociodemographic characteristics in a single model. To do so would also require defining multiple health states which would render the analysis entirely too complex. We show that DES resolve these weaknesses and that its flexibility allow patients with differing attributes to move from one event to another in sequential order while simultaneously taking into account important risk factors such as age, gender, disease history and patients attitude towards treatment, together with any disease-related events (adverse events, suicide attempt etc.).

CONCLUSION

DES modelling appears to be an accurate, flexible and comprehensive means of depicting disease progression compared with conventional simulation methodologies. Its use in analysing recurrent and chronic diseases appears particularly useful compared with Markov processes.

Does America spend enough on addiction treatment? Results from public opinion surveys

Addiction treatment is often misunderstood and underappreciated in the United States. Although a large body of literature clearly demonstrates the clinical and economic benefits of addiction treatment for many clients and in most settings, the general public has a somewhat ambivalent attitude toward treatment expansion and taxpayer financing. A potential reason for this disconnect between economic evidence and public opinion is a weak identification with the need for, or the success of, addiction treatment for those individuals without a substance abuse problem themselves or in members of their family. Alternatively, addiction treatment stakeholders may be delivering an ineffective or misdirected message about the social value of this industry. This article explores these and other potential explanations for the paradoxically low placement of the addiction treatment industry among other socially important institutions in the United States. Although none of the explanations advanced in this article has been scientifically tested or verified, it is hoped that the historical inquiry and information provided herein will offer practical strategies for the stability and growth of the addiction treatment industry.