Treatment retention in opioid agonist therapy: comparison of methadone versus buprenorphine/naloxone by analysis of daily-witnessed dispensed medication in a Canadian Province

A Scoping Review of Evidence-Based Interventions and Health-Related Services for Youth Who Use Nonmedical Opioids in Canada and the United States

PURPOSE

This scoping review synthesizes the characteristics and outcomes of recent evidence-based treatments and services for youth with nonmedical opioid use/opioid use disorder in the context of the ongoing opioid crisis in Canada and the United States.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - Extension for Scoping Reviews guidelines, empirical health databases were searched for literature describing treatments or health-related services for nonmedical opioid use/opioid use disorder among youth (ages 12-25). Two independent reviewers conducted study screening, selection, and data extraction. A deductive content analysis further synthesized the interventions' characteristics following the Consolidated Framework for Implementation Research and an inductive content analysis synthesized the interventions' efficacy/effectiveness outcomes.

RESULTS

Twenty-five articles met inclusion from 2,761 screened; 88% described opioid agonist treatment (alone or in combination with nonpharmacological treatment). Following the Consolidated Framework for Implementation Research, commonly identified adaptable characteristics included treatment decision-making processes, integrated health and social services, and treatment settings. Efficacy/effectiveness outcomes most frequently included substance use and treatment engagement.

DISCUSSION

This study informs future development, implementation, and evaluation of practices and policies that could be tailored to improve the quality of opioid agonist treatment for youth at risk of significant harms from nonmedical opioid use.

Effectiveness of buprenorphine (naloxone) for opioid dependence does not differ across opioid categories: a retrospective cohort study from India

We aimed to examine whether treatment retention, abstinence, and adherence to buprenorphine-naloxone (BNX) differ among individuals with opioid dependence (OD) across three common categories of opioids- heroin, opium, and low-potency pharmaceutical. In a retrospective cohort study, we analyzed outpatient treatment records from March 2020 through February 2022. Opioid category was determined by lifetime and current opioid use. We defined treatment retention as weeks of uninterrupted clinic attendance. Abstinence and BNX adherence were calculated by weeks of extra-medical opioid-negative and buprenorphine-positive urine screening from treatment initiation. Four-hundred-thirteen patients were eligible; 406 (98.3%) were included in the final analysis. Two-hundred-ninety (71.4%) patients were dependent on heroin; 66 (16.3%) were natural opioid dependent, and 50 (12.3%) were dependent on low-potency pharmaceutical opioids. BNX effectiveness in treatment retention, abstinence, and adherence did not differ in patients dependent on heroin, natural, and low-potency pharmaceutical opioids. Patients on ≥8 mg daily BNX had better retention and adherence than those on <8 mg daily. Patients from lower socioeconomic status (SES) had higher odds of retention, abstinence, and adherence than those from upper/middle SES. Treatment outcomes on BNX did not differ across opioid categories. However, BNX should be dosed adequately.

Retention and critical outcomes among new methadone maintenance patients following extended take-home reforms: a retrospective observational cohort study

Background

Approximately 1800 opioid treatment programs (OTPs) in the US dispense methadone to upwards of 400,000 patients with opioid use disorder (OUD) annually, operating under longstanding highly restrictive guidelines. OTPs were granted novel flexibilities beginning March 15, 2020, allowing for reduced visit frequency and extended take-home doses to minimize COVID exposure with great variation across states and sites. We sought to use electronic health records to compare retention in treatment, opioid use, and adverse events among patients newly entering methadone maintenance in the post-reform period in comparison with year-ago, unexposed, controls.

Methods

Retrospective observational cohort study across 9 OTPs, geographically dispersed, in the National Institute of Drug Abuse (NIDA) Clinical Trials Network. Newly enrolled patients between April 15 and October 14, 2020 (post-COVID, reform period) v. March 15-September 14, 2019 (pre-COVID, control period) were assessed. The primary outcome was 6-month retention. Secondary outcomes were opioid use and adverse events including emergency department visits, hospitalizations, and overdose.

Findings

821 individuals were newly admitted in the post-COVID and year-ago control periods, average age of 38.3 (SD 11.1), 58.9% male. The only difference across pre- and post-reform groups was the prevalence of psychostimulant use disorder (25.7% vs 32.9%, p = 0.02). Retention was non-inferior (60.0% vs 60.1%) as were hazards of adverse events in the aggregate (X2 (1) = 0.55, p = 0.46) in the post-COVID period. However, rates of month-level opioid use were higher among post-COVID intakes compared to pre-COVID controls (64.8% vs 51.1%, p < 0.001). Moderator analyses accounting for stimulant use and site-level variation in take-home schedules did not change findings.

Interpretation

Policies allowing for extended take-home schedules were not associated with worse retention or adverse events despite slightly elevated rates of measured opioid use while in care. Relaxed guidelines were not associated with measurable increased harms and findings could inform future studies with prospective trials.

Funding

USDHHSNIDACTNUG1DA013035-15.

Endogenous opiates and behavior: 2022

This paper is the forty-fifth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2022 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Characterizing opioid agonist therapy uptake and factors associated with treatment retention among people with HIV in British Columbia, Canada

Accidental overdoses are now the leading cause of death among people with HIV (PWH) in British Columbia (BC). We examined the utilization and retention of opioid agonist therapy (OAT). Adult PWH (≥19 years) with ≥ 1 OAT dispensation in BC between 2008 and 2020 were included (n = 1,515). OAT treatment episodes were formed based on specific criteria for slow-release oral morphine (SROM), methadone, injectable OAT (iOAT), and buprenorphine/naloxone. Retention in treatment was defined as any episode lasting ≥ 12 months. Logistic regression with generalized estimating equations modeled retention-associated factors. There was a 56.6% decline in OAT retention over time. Buprenorphine treatment exhibited significantly lower odds of retention (OR: 0.58; 95% CI: 0.36-0.92) compared to methadone. Conversely, no significant change in retention odds was observed for SROM (0.72; 0.33-1.54) and iOAT (0.81; 0.31-2.12). Factors associated with increased odds of retention included a 10-year increase in age (1.69; 1.46-1.95), previous retention history (1.96; 1.40-2.73), achieving OAT therapeutic dose (8.22; 6.67-10.14), and suppressed HIV viral load (1.35; 1.10-1.67). Individuals with a lifetime HCV diagnosis receiving iOAT were more likely to retain (3.61; 1.20-10.83). Each additional year on OAT during the study period was associated with a 4% increase in the odds of retention. A significant proportion of PWH had a history of OAT prescribing but experienced low retention rates. Retention outcomes were more positive for SROM and iOAT. The association between OAT medication type and retention odds may be particularly influenced by HCV diagnosis. Optimal management of opioid use disorder among PWH, with an emphasis on attaining the therapeutic dose is crucial.

Buprenorphine versus methadone for the treatment of opioid dependence: a systematic review and meta-analysis of randomised and observational studies

BACKGROUND

Opioid dependence is associated with substantial health and social burdens, and opioid agonist treatment (OAT) is highly effective in improving multiple outcomes for people who receive this treatment. Methadone and buprenorphine are common medications provided as OAT. We aimed to examine buprenorphine compared with methadone in the treatment of opioid dependence across a wide range of primary and secondary outcomes.

METHODS

We did a systematic review and meta-analysis in accordance with GATHER and PRISMA guidelines. We searched Embase, MEDLINE, CENTRAL, and PsycINFO from database inception to Aug 1, 2022; clinical trial registries and previous relevant Cochrane reviews were also reviewed. We included all RCTs and observational studies of adults (aged ≥18 years) with opioid dependence comparing treatment with buprenorphine or methadone. Primary outcomes were retention in treatment at 1, 3, 6, 12, and 24 months, treatment adherence (measured through doses taken as prescribed, dosing visits attended, and biological measures), or extra-medical opioid use (measured by urinalysis and self-report). Secondary outcomes were use of benzodiazepines, cannabis, cocaine, amphetamines, and alcohol; withdrawal; craving; criminal activity and engagement with the criminal justice system; overdose; mental and physical health; sleep; pain; global functioning; suicidality and self-harm; and adverse events. Single-arm cohort studies and RCTs that collected data on buprenorphine retention alone were also reviewed. Data on study, participant, and treatment characteristics were extracted. Study authors were contacted to obtain additional data when required. Comparative estimates were pooled with use of random-effects meta-analyses. The proportion of individuals retained in treatment across multiple timepoints was pooled for each drug. This study is registered with PROSPERO (CRD42020205109).

FINDINGS

We identified 32 eligible RCTs (N=5808 participants) and 69 observational studies (N=323 340) comparing buprenorphine and methadone, in addition to 51 RCTs (N=11 644) and 124 observational studies (N=700 035) that reported on treatment retention with buprenorphine. Overall, 61 studies were done in western Europe, 162 in North America, 14 in north Africa and the Middle East, 20 in Australasia, five in southeast Asia, seven in south Asia, two in eastern Europe, three in central Europe, one in east Asia, and one in central Asia. 1 040 827 participants were included in these primary studies; however, gender was only reported for 572 111 participants, of whom 377 991 (66·1%) were male and 194 120 (33·9%) were female. Mean age was 37·1 years (SD 6·0). At timepoints beyond 1 month, retention was better for methadone than for buprenorphine: for example, at 6 months, the pooled effect favoured methadone in RCTs (risk ratio 0·76 [95% CI 0·67-0·85]; I·=74·2%; 16 studies, N=3151) and in observational studies (0·77 [0·68-0·86]; I·=98·5%; 21 studies, N=155 111). Retention was generally higher in RCTs than observational studies. There was no evidence suggesting that adherence to treatment differed with buprenorphine compared with methadone. There was some evidence that extra-medical opioid use was lower in those receiving buprenorphine in RCTs that measured this outcome by urinalysis and reported proportion of positive urine samples (over various time frames; standardised mean difference -0·20 [-0·29 to -0·11]; I·=0·0%; three studies, N=841), but no differences were found when using other measures. Some statistically significant differences were found between buprenorphine and methadone among secondary outcomes. There was evidence of reduced cocaine use, cravings, anxiety, and cardiac dysfunction, as well as increased treatment satisfaction among people receiving buprenorphine compared with methadone; and evidence of reduced hospitalisation and alcohol use in people receiving methadone. These differences in secondary outcomes were based on small numbers of studies (maximum five), and were often not consistent across study types or different measures of the same constructs (eg, cocaine use).

INTERPRETATION

Evidence from trials and observational studies suggest that treatment retention is better for methadone than for sublingual buprenorphine. Comparative evidence on other outcomes examined showed few statistically significant differences and was generally based on small numbers of studies. These findings highlight the imperative for interventions to improve retention, consideration of client-centred factors (such as client preference) when selecting between methadone and buprenorphine, and harmonisation of data collection and reporting to strengthen future syntheses.

FUNDING

Australian National Health and Medical Research Council.