Comparative effectiveness of buprenorphine-naloxone versus methadone for treatment of opioid use disorder: a population-based observational study protocol in British Columbia, Canada

Prescribing practices in opioid agonist treatment and changes in compliance to clinical dosing guidelines in British Columbia, Canada

BACKGROUND AND AIM

In British Columbia, Canada, clinical guidelines for the treatment of opioid use disorders (OUD) were updated in 2017, during a period in which the potency and composition of the illicit drug supply changed rapidly. We aimed to describe changes in opioid agonist treatment (OAT) prescribing practices at the population level in a setting in which fentanyl and its analogs have become the primary illicit opioid of use.

DESIGN, SETTING AND PARTICIPANTS

This was a population-based retrospective cohort study using three linked health administrative databases in British Columbia (BC), Canada. All individuals with at least one OAT dispensation in BC between 1 January 2014 and 31 August 2021 took part.

MEASUREMENTS

To assess changes in OAT prescribing practices over time, we calculated initiation doses, dose titration intervals, maintenance doses and take-home dosing intervals stratified by medication [methadone, buprenorphine-naloxone and slow-release oral morphine (SROM)] according to recommended guidelines.

FINDINGS

A total of 265 410 OAT episodes (57.5% on methadone, 34.5% on buprenorphine-naloxone and 8.0% on SROM) were initiated during the study period. Compared with the guideline recommendation, observed initiation doses were higher among all medications from 2014 (2017 for SROM) to 2021 (buprenorphine-naloxone: 14-29%; methadone: 53-66%; SROM: 26-55%). Titration intervals were shorter for all medications, consistent with guidelines for buprenorphine-naloxone (26-49%), but shorter than recommended for methadone or SROM (28-51% and 12-41%, respectively). Higher maintenance dosing was observed for methadone (68-78%) and SROM (3-21%). Take-home allowances extending beyond the recommended guideline length increased across medications (buprenorphine-naloxone: 18-35%; methadone: 50-64%; SROM: 34-39%). Changes in prescribing patterns were similar for first-time OAT initiators.

CONCLUSION

In British Columbia, Canada, from 2014 to 2021, prescribers of opioid agonist treatment (OAT) appeared to initiate both new and experienced OAT clients at higher doses than guideline recommendations, titrate them more rapidly and maintain clients at higher doses. Take-home dose allowances also gradually increased.

The role of attachment and personality traits in choosing opiate addiction replacement therapy

Contemporary medical approaches for opioid addiction often include medication-assisted therapy, utilizing methadone and buprenorphine. However, factors influencing patient preferences for starting buprenorphine or methadone therapy are poorly understood. This study aims to explore whether variances in personality traits and attachment styles are related to treatment preferences among individuals undergoing buprenorphine and methadone maintenance therapies. 300 participants completed the Big Five Questionnaire for personality traits and sub-dimensions and the Experiences in Close Relationship Scale for assessing attachment styles. The results indicated that patients with higher levels of Dynamism, Conscientiousness, and Perseverance personality traits were more likely to choose buprenorphine over methadone for achieving and maintaining abstinence. Although attachment styles showed a greater ability to differentiate between groups compared to personality traits, the differences were not significant. However, Conscientiousness stood out for its high discriminant validity, suggesting that scores in this personality dimension could significantly distinguish between groups, with individuals in the buprenorphine group showing higher levels of Conscientiousness compared to the methadone group. The study suggests a partial association between individuals' preference for abstinence therapy and their personality traits. These findings could be considered useful indicators when choosing maintenance therapy to help opiate-addicted patients achieve and maintain abstinence.

Optimizing Safe Opioid Prescribing: A Paradigm Shift in Buprenorphine Management for Orthopaedic Surgery

The worsening opioid epidemic in the United States, exacerbated by the COVID-19 pandemic, necessitates innovative approaches to pain management. Buprenorphine, a long-acting opioid, has gained popularity due to its safety profile and accessibility. Orthopaedic surgeons, encountering an increasing number of patients on buprenorphine, face challenges in perioperative management. This article will update orthopaedic surgeons on new developments in the understanding of buprenorphine as a pain reliever and share evidence-based practice guidelines for buprenorphine management. For patients on buprenorphine for opioid use disorder or chronic pain, the updated recommendation is to continue their home dose of buprenorphine through the perioperative period. The patient's buprenorphine prescriber should be contacted and notified of any impending surgery. The continuation of buprenorphine should be accompanied by a multimodal approach to analgesia, including a preoperative discussion about expectations of pain and pain control, regional anesthesia, standing acetaminophen, Nonsteroidal anti-inflammatory drugs when possible, gabapentinoids at night for patients under 65 years, cryotherapy, elevation, and early mobilization. Patients can also be prescribed short-acting, immediate-release opioids for breakthrough pain. Transdermal buprenorphine is emerging as an excellent option for the management of acute perioperative pain in both elective and nonelective orthopaedic patients. A single patch can provide a steady dose of pain medication for up to 1 week during the postoperative period. A patch delivery method can help combat patient nonadherence and ultimately provide better overall pain control. In the future, transdermal buprenorphine patches could be applied in virtually all fracture surgery, spinal surgery, total joint arthroplasty, ligament reconstructions with bony drilling, etc. As the stigma surrounding buprenorphine decreases, further opportunities for perioperative use may develop.

Comparative Analysis of Instrumental Variables on the Assignment of Buprenorphine/Naloxone or Methadone for the Treatment of Opioid Use Disorder

BACKGROUND

Instrumental variable (IV) analysis provides an alternative set of identification assumptions in the presence of uncontrolled confounding when attempting to estimate causal effects. Our objective was to evaluate the suitability of measures of prescriber preference and calendar time as potential IVs to evaluate the comparative effectiveness of buprenorphine/naloxone versus methadone for treatment of opioid use disorder (OUD).

METHODS

Using linked population-level health administrative data, we constructed five IVs: prescribing preference at the individual, facility, and region levels (continuous and categorical variables), calendar time, and a binary prescriber's preference IV in analyzing the treatment assignment-treatment discontinuation association using both incident-user and prevalent-new-user designs. Using published guidelines, we assessed and compared each IV according to the four assumptions for IVs, employing both empirical assessment and content expertise. We evaluated the robustness of results using sensitivity analyses.

RESULTS

The study sample included 35,904 incident users (43.3% on buprenorphine/naloxone) initiated on opioid agonist treatment by 1585 prescribers during the study period. While all candidate IVs were strong (A1) according to conventional criteria, by expert opinion, we found no evidence against assumptions of exclusion (A2), independence (A3), monotonicity (A4a), and homogeneity (A4b) for prescribing preference-based IV. Some criteria were violated for the calendar time-based IV. We determined that preference in provider-level prescribing, measured on a continuous scale, was the most suitable IV for comparative effectiveness of buprenorphine/naloxone and methadone for the treatment of OUD.

CONCLUSIONS

Our results suggest that prescriber's preference measures are suitable IVs in comparative effectiveness studies of treatment for OUD.

Improving the effectiveness of SUD treatment through a national registry

CONTEXT

Recent research into the effectiveness of abstinence-based substance use disorder (SUD) treatment indicates that there has not been a substantial improvement since the Drug Abuse Treatment Outcome Study research in 1993. Research into medication-supported treatments for SUD are hindered by a dearth of real-world longitudinal outcome studies. Patient registries have dramatically improved survival rates in many diseases by providing researchers with longitudinal data on a broad spectrum of patients undergoing a variety of treatments. Policy prescription: We recommend the creation of a national registry for patients receiving treatment for SUD akin to the Surveillance, Epidemiology, and End Results Program established in 1971 to track cancer patient outcomes. One option would be to expand the data currently being collected in the Treatment Episode Data Set (TEDS) to include all nonpublicly funded treatment and to allow for longitudinal tracking of deidentified individuals. Information on medication use and deaths could be kept up to date through integrations with state-wide death registries and Prescription Drug Monitoring Programs. The TEDS dataset already undergoes extensive data deidentification to make sure individuals cannot be identified prior to releasing the admissions and discharge datasets to researchers. Once longitudinal tracking is available, even more stringent deidentification will be necessary, and access to the dataset would be restricted to public health researchers.

CONCLUSION

The development of a registry of individuals undergoing treatment for SUD can be expected to enhance our understanding of the progression of the disease and the relative effectiveness of different treatment modalities for patients with different drug use histories and characteristics.

Opioid agonist therapy and mortality among First Nations and other residents with concurrent alcohol use disorder in British Columbia, Canada: A population-based cohort study

BACKGROUND

Despite the prevalence of alcohol use among people with opioid use disorder (PWOUD) engaged in opioid agonist therapy (OAT), clinical care guidance for concurrent alcohol use disorder (AUD) and OUD is scarce. We assessed the prevalence and risk of mortality for concurrent AUD among PWOUD who accessed OAT in British Columbia (BC).

METHODS

Data were obtained from six linked population-level health administrative datasets to identify PWOUD from January 1996 to March 2020. All-cause age and sex standardized mortality ratios (SMR) were calculated to determine the mortality risk by OAT status (on vs. discontinued), stratified by First Nations and other residents with concurrent AUD and OUD. Adjusted risk ratios compared the relative risk of mortality by AUD status (AUD detected vs. not) among First Nations and other residents.

RESULTS

We identified 62,110 PWOUD who received OAT, including 6305 (10.2%) First Nations. OAT substantially lowered the SMR among First Nations (SMR=6.6, 95% CI: 5.4-8.1) and other residents (SMR=6.6; 95% CI: 6.2-7.0) with concurrent AUD and OUD, compared to those who discontinued (SMR=22.7, 95% CI: 20.4-25.1, SMR=17.5, 95% CI: 16.8-18.2 respectively). The risk of mortality was 1.9 (95% CI: 1.6-2.2) times higher for First Nations and 2.0 (95% CI: 1.8-2.2) times higher for other residents with concurrent OUD and AUD compared to those without an indication of AUD.

CONCLUSIONS

The protective effect of OAT remained despite the presence of a concurrent AUD among both First Nations and other residents with OUD. Findings have implications for clinical care management of concurrent disorders.

Comparative effectiveness of urine drug screening strategies alongside opioid agonist treatment in British Columbia, Canada: a population-based observational study protocol

INTRODUCTION

Urine drug tests (UDTs) are commonly used for monitoring opioid agonist treatment (OAT) responses, supporting the clinical decision for take-home doses and monitoring potential diversion. However, there is limited evidence supporting the utility of mandatory UDTs-particularly the impact of UDT frequency on OAT retention. Real-world evidence can inform patient-centred approaches to OAT and improve current strategies to address the ongoing opioid public health emergency. Our objective is to determine the safety and comparative effectiveness of alternative UDT monitoring strategies as observed in clinical practice among OAT clients in British Columbia, Canada from 2010 to 2020.

METHODS AND ANALYSIS

We propose a population-level retrospective cohort study of all individuals 18 years of age or older who initiated OAT from 1 January 2010 to 17 March 2020. The study will draw on eight linked health administrative databases from British Columbia. Our primary outcomes include OAT discontinuation and all-cause mortality. To determine the effectiveness of the intervention, we will emulate a 'per-protocol' target trial using a clone censoring approach to compare fixed and dynamic UDT monitoring strategies. A range of sensitivity analyses will be executed to determine the robustness of our results.

ETHICS AND DISSEMINATION

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Ethics Board and the Simon Fraser University Office of Research Ethics. Results will be disseminated to local advocacy groups and decision-makers, national and international clinical guideline developers, presented at international conferences and published in peer-reviewed journals electronically and in print.

Cost-effectiveness of flexible take-home buprenorphine-naloxone versus methadone for treatment of prescription-type opioid use disorder

BACKGROUND

Our objective was to examine the cost-effectiveness of flexible take-home buprenorphine-naloxone (BNX) versus methadone alongside the OPTIMA trial in Canada.

METHODS

The OPTIMA study was a pragmatic, open-label, noninferiority, two-arm randomized controlled trial, to assess the comparative effectiveness of flexible take-home BNX vs. methadone in routine clinical care for individuals with prescription-type opioid use disorder. We evaluated cost-effectiveness using a semi-Markov cohort model. Probabilities of overdose were calibrated, accounting for fentanyl prevalence and other overdose risk factors such as naloxone availability. We considered health sector and societal cost perspectives, including costs (2020 CAD) for treatment, health resource use, criminal activity, and health state-specific preference weights as outcomes to calculate incremental cost-effectiveness ratios. Six-month and lifetime (3% annual discount rate) time-horizons were explored.

RESULTS

Over a lifetime time horizon, individuals accumulated -0.144 [CI: -0.302, -0.025] incremental quality-adjusted life years (QALYs) in BNX compared with methadone. Incremental costs were -$2047 [CI: -$39,197, $24,250] from a societal perspective, and -$4549 [CI: -$6332, -$3001] from a health sector perspective. Over a six-month time-horizon, individuals accumulated 0.002 [credible interval (CI): -0.011, 0.016] incremental QALYs in BNX compared with methadone. Incremental costs were -$307 [CI: -$10,385, $8466] from a societal perspective and -$1111 [CI: -$1517, -$631] from a health sector perspective. BNX was dominated (costlier, less effective) in 49.7% of simulations when adopting a societal perspective over a lifetime time horizon.

CONCLUSIONS

Flexible take-home BNX was not cost-effective versus methadone over a lifetime time horizon, resulting from better treatment retention in methadone compared to BNX.

Access to tablet injectable opioid agonist therapy in rural and smaller urban settings in British Columbia, Canada: a qualitative study

BACKGROUND

Rural and smaller urban settings in Canada are disproportionately impacted by the overdose crisis, highlighting the need for novel public health interventions within these jurisdictions. Tablet injectable opioid agonist therapy (TiOAT) programs have been implemented in select rural communities as a means to address drug-related harms. However, little is known about the accessibility of these novel programs. Therefore, we conducted this study to understand the rural context and factors that affected access of TiOAT programs.

METHODS

Between October 2021 to April 2022, individual qualitative semi-structured interviews were conducted with 32 individuals enrolled in a TiOAT program at participating rural and smaller urban sites in British Columbia, Canada. Interview transcripts were coded using NVivo 12 and data were analyzed thematically.

RESULTS

TiOAT access varied considerably. TiOAT delivery in rural settings is complicated due to geographic challenges. Participants who were homeless and staying at a nearby shelter or those in centrally-located supportive housing had minimal issues compared to those living in more affordable housing on the outskirts of town with limited transportation options. Dispensing policies that required daily-witnessed ingestion multiple times daily were challenging for most. Only one site provided evening take-home doses whereas participants at the other site could only resort to the illicit opioid supply to address withdrawal outside of program hours. Participants described the clinics as providing a positive and familial social environment compared to experiences of stigma elsewhere. Medication interruptions did occur when participants were in hospital and custodial settings, leading to withdrawal, program discontinuation, and overdose risk.

CONCLUSIONS

This study highlights the beneficial ways in which health services tailored for people who use drugs can create a stigma-free environment with an emphasis on social bonds. Other factors such as transportation access, dispensing policies, and access in rural hospitals and custodial settings produced unique challenges for rural people who use drugs. Public health authorities in rural and smaller settings should consider these factors when designing, implementing, and scaling up future substance use services, including TiOAT programs.

Advancing virtual primary care for people with opioid use disorder (VPC OUD): a mixed-methods study protocol

INTRODUCTION

The emergence of COVID-19 introduced a dual public health emergency in British Columbia, which was already in the fourth year of its opioid-related overdose crisis. The public health response to COVID-19 must explicitly consider the unique needs of, and impacts on, communities experiencing marginalisation including people with opioid use disorder (PWOUD). The broad move to virtual forms of primary care, for example, may result in changes to healthcare access, delivery of opioid agonist therapies or fluctuations in co-occurring health problems that are prevalent in this population. The goal of this mixed-methods study is to characterise changes to primary care access and patient outcomes following the rapid introduction of virtual care for PWOUD.

METHODS AND ANALYSIS

We will use a fully integrated mixed-methods design comprised of three components: (a) qualitative interviews with family physicians and PWOUD to document experiences with delivering and accessing virtual visits, respectively; (b) quantitative analysis of linked, population-based administrative data to describe the uptake of virtual care, its impact on access to services and downstream outcomes for PWOUD; and (c) facilitated deliberative dialogues to co-create educational resources for family physicians, PWOUD and policymakers that promote equitable access to high-quality virtual primary care for this population.

ETHICS AND DISSEMINATION

Approval for this study has been granted by Research Ethics British Columbia. We will convene PWOUD and family physicians for deliberative dialogues to co-create educational materials and policy recommendations based on our findings. We will also disseminate findings via traditional academic outputs such as conferences and peer-reviewed publications.

Validation and endorsement of health system performance measures for opioid use disorder in British Columbia, Canada: A Delphi panel study

Background

Limited data exists on the performance of the healthcare system in opioid use disorder (OUD). We evaluated the face validity and potential risks of a set of health system performance measures for OUD collaboratively with clinicians, policymakers and people with lived experience of opioid use (PWLE) in the interest of establishing an endorsed set of measures for public reporting.

Methods

Through a two-stage Delphi-panel approach, a panel of clinical and policy experts validated and considered 102 previously constructed OUD performance measures for endorsement using information on measurement construction, sensitivity analyses, quality of evidence, predictive validity, and feedback from local PWLE. We collected quantitative and qualitative survey responses from 49 clinicians and policymakers, and 11 PWLE. We conducted inductive and deductive thematic analysis to present qualitative responses.

Results

A total of 37 measures of 102 were strongly endorsed (9/13 cascade of care, 2/27 clinical guideline compliance, 17/44 healthcare integration, and 9/18 healthcare utilization measures). Thematic analysis of responses revealed several themes regarding measurement validity, unintended consequences, and key contextual considerations. Overall, measures related to the cascade of care (excluding opioid agonist treatment dose tapering) received strong endorsements. PWLE highlighted barriers to accessing treatment, undignified aspects of treatment, and lack of a full continuum of care as their concerns.

Conclusion

We defined 37 endorsed health system performance measures for OUD and presented a range of perspectives on their validity and use. These measures provide critical considerations for health system improvement in the care of people with OUD.

The effect of a methadone reformulation on opioid agonist treatment outcomes: A population-based study in British Columbia, Canada, 2013-14

INTRODUCTION

The province of British Columbia, Canada, changed the existing oral anhydrous methadone solution to a 10-times more concentrated pre-mixed solution, Methadose®, on February 1, 2014. We aimed to assess the immediate effects of the methadone reformulation on missed doses, days off methadone, changes in medication dosing and dispensations of opioids for pain, and hospitalizations and mortality among all people receiving treatment at or near the time of the change.

METHODS

We conducted a population-based retrospective cohort study including all individuals receiving at least one methadone dispensation in the 12 months prior to the study period. We executed a difference-in-differences analysis by estimating a multivariate regression model to compare outcomes in the three months before and after the reformulation (November 1, 2013 to April 30, 2014) versus a time-lagged control cohort with similar characteristics observed during an equivalent nonoverlapping interval. We used daily individual-level linked health administrative data capturing missed doses, days off methadone, changes in methadone dosing, concurrent dispensations of opioids for pain, hospitalizations, and mortality. We stratified the cohorts into three subgroups: (i) those receiving OAT for ≥12 months; (ii) those receiving OAT for <12 months; and (iii) those not receiving OAT at the start of the study period. We conducted sensitivity analyses and placebo tests to assess the robustness of our results.

RESULTS

Among the 16,339 individuals receiving methadone during the study period, the reformulation was associated with more instances of methadone dose increases (34.5% [95% Confidence Interval (CI): 27.4%, 41.5%]). For those retained in treatment ≥12 months prior to the study period (n = 7449), the reformulation was associated with more instances of methadone dose increases (50.2% [39.5%, 60.8%]) and dispensations of opioids for pain (62.2% [40.8%, 83.5%]), as well as an increase in missed doses (41.9% [29.1%, 54.7%]) and days off methadone (62.6% [39.7%, 85.4%]). We found no statistically significant change in risk of hospitalization or mortality. Sensitivity analyses supported our results.

CONCLUSION

Our results reinforce the need expressed by people receiving methadone for greater client involvement in the planning and implementation of regulatory changes that may impact client care, especially those patients with a relatively long treatment history.

Endogenous opiates and behavior: 2020

This paper is the forty-third consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2020 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).

Modeling the population-level impact of opioid agonist treatment on mortality among people accessing treatment between 2001 and 2020 in New South Wales, Australia

BACKGROUND AND AIMS

The individual-level effectiveness of opioid agonist treatment (OAT) in reducing mortality is well established, but there is less evidence on population-level benefits. We use modeling informed with linked data from the OAT program in New South Wales (NSW), Australia, to estimate the impact of OAT provision in the community and prisons on mortality and the impact of eliminating excess mortality during OAT initiation/discontinuation.

DESIGN

Dynamic modeling.

SETTING AND PARTICIPANTS

A cohort of 49 359 individuals who ever received OAT in NSW from 2001 to 2018.

MEASUREMENTS

Receipt of OAT was represented through five stages: (i) first month on OAT, (ii) short (1-9 months) and (iii) longer (9+ months) duration on OAT, (iv) first month following OAT discontinuation and (v) rest of time following OAT discontinuation. Incarceration was represented as four strata: (i) never or not incarcerated in the past year, (ii) currently incarcerated, (iii) released from prison within the past month and (iv) released from prison 1-12 months ago. The model incorporated elevated mortality post-release from prison and OAT impact on reducing mortality and incarceration.

FINDINGS

Among the cohort, mortality was 0.9 per 100 person-years, OAT coverage and retention remained high (> 50%, 1.74 years/episode). During 2001-20, we estimate that OAT provision reduced overdose and other cause mortality among the cohort by 52.8% [95% credible interval (CrI) = 49.4-56.9%] and 26.6% (95% CrI =22.1-30.5%), respectively. We estimate 1.2 deaths averted and 9.7 life-years gained per 100 person-years on OAT. Prison OAT with post-release OAT-linkage accounted for 12.4% (95% CrI = 11.5-13.5%) of all deaths averted by the OAT program, primarily through preventing deaths in the first month post-release. Preventing elevated mortality during OAT initiation and discontinuation could have averted up to 1.4% (95% CrI =  0.8-2.0%) and 3.0% (95% CrI = 2.1-5.3%) of deaths, respectively.

CONCLUSION

The community and prison opioid agonist treatment program in New South Wales, Australia appears to have substantially reduced population-level overdose and all-cause mortality in the past 20 years, partially due to high retention.

Development and validation of health system performance measures for opioid use disorder in British Columbia, Canada

BACKGROUND

Performance measurement provides an evidence-based means to inform development of interventions to improve the quality of care for people who use opioids. We aimed to develop and assess the predictive validity of health system performance measures for opioid use disorder (OUD) in British Columbia (BC), Canada.

METHODS

Performance measures were generated using retrospective population-level administrative datasets (both provincial and regional) and publicly-reported retrospective data according to four domains (care engagement, clinical guideline compliance, integration, and healthcare utilization). The adjusted odds ratio was estimated via generalized linear mixed models to determine predictive validity for all-cause hospitalization or mortality within 6 months of measurement.

FINDINGS

A total of 102 performance measures were constructed. We identified 55,470 diagnosed PWOUD, and 39,456 ever engaged in opioid agonist treatment (OAT). We found divergent rates of treatment for concurrent conditions (7.4% for alcohol use disorder to 80.1% for HIV/AIDS), low levels of linkage to OAT and other outpatient care following acute care, and increasing levels of service provision, including increases in OAT prescribers and pharmacies, naloxone kit distribution and overdose prevention site visitation. Our analyses on the predictive validity measures largely supported a priori hypotheses on the direction of effect on the outcome.

CONCLUSIONS

We identified a range of priorities to improve the quality of care for PWOUD, with critical gaps in linkage to care through acute care settings and long-term engagement in OAT. The proposed measures can be derived for geographic and clinical subgroups and updated over time, providing a basis to monitor and evaluate efforts to address the public health burden of OUD.

Assessing the determinants of completing OAT induction and long-term retention: A population-based study in British Columbia, Canada

BACKGROUND

Pharmacological treatments for opioid use disorder are essential, life-saving medications, yet successful induction of them and long-term retention on them is limited in many settings. Induction into opioid agonist treatment (OAT) features the highest risk of mortality throughout the treatment course, and greatest risk of discontinuation. We aimed to identify determinants of completing OAT induction and, among those completing induction, time to OAT discontinuation in British Columbia (BC), Canada.

METHODS

We conducted a retrospective study using linked population-level health administrative databases to capture all individuals in BC receiving at least one OAT dispensation from January 1, 2008, to September 30, 2018. We constructed covariates capturing client demographics, clinical history, and characteristics of the treatment episode and the primary prescribing physician. We estimated a two-part model to identify determinants of the probability of completing induction using a generalized linear mixed model with logit link and the time to OAT discontinuation among those completing induction using a Cox proportional hazards frailty model.

RESULTS

We observed 220,474 OAT episodes (73.9% initiated with methadone, 24.7% with buprenorphine, and 1.4% with slow-release oral morphine) among 45,608 individuals over the study period. Less than 60% of all OAT episodes completed induction (59.0% for methadone episodes, 56.7% for buprenorphine/naloxone, 41.0% for slow-release oral morphine) and half of all episodes that completed induction reached the minimum effective dosage (51.0% for methadone episodes [60 mg/day], 48.2% for buprenorphine/naloxone [12 mg/day], 59.4% for slow-release oral morphine [240 mg/day]). In multiple regression analysis, the adjusted odds of completing induction with buprenorphine improved over time, exceeding that of methadone in 2018: 1.46 (1.40, 1.51). For those who completed induction, buprenorphine use was associated with shorter times to discontinuation throughout the study period, but the estimated rate of discontinuation decreased over time (adjusted hazard ratio, vs. methadone in 2008: 2.50 (2.35, 2.66); in 2018: 1.79 (1.74, 1.85)).

CONCLUSION

We found low rates of completing OAT induction and, for those who did complete it, low rates of reaching the minimum effective dose.

Chronic opioid use modulates human enteric microbiota and intestinal barrier integrity

Over the past three decades the United States has experienced a devastating opioid epidemic. One of the many debilitating side effects of chronic opioid use is opioid-induced bowel dysfunction. We investigated the impact of methadone maintenance treatment (MMT) on the gut microbiome, the gut bacterial metabolite profile, and intestinal barrier integrity. An imbalance in key bacterial communities required for production of short-chain fatty acids (SCFAs), mucus degradation, and maintenance of barrier integrity was identified. Consistent with dysbiosis, levels of fecal SCFAs were reduced in MMT. We demonstrated that metabolites synthesized by Akkermansia muciniphila modulate intestinal barrier integrity in vitro by strengthening the pore pathway and regulating tight junction protein expression. This study provides essential information about the therapeutic potential of A. muciniphila and warrants development of new clinical strategies that aim to normalize the gut microbiome in individuals affected by chronic opioid use.

Opioid Use Disorder and Perinatal Outcomes

OBJECTIVES

Evidence on the perinatal health of mother-infant dyads affected by opioids is limited. Elevated risks of opioid-related harms for people with opioid use disorder (OUD) increase the urgency to identify protective factors for mothers and infants. Our objectives were to determine perinatal outcomes after an OUD diagnosis and associations between opioid agonist treatment and birth outcomes.

METHODS

We conducted a population-based retrospective study among all women with diagnosed OUD before delivery and within the puerperium period in British Columbia, Canada, between 2000 and 2019 from provincial health administrative data. Controlling for demographic and clinical characteristics, we determined associations of opioid agonist treatment on birth weight, gestational age, infant disorders related to gestational age and birth weight, and neonatal abstinence syndrome via logistic regression.

RESULTS

The population included 4574 women and 6720 live births. Incidence of perinatal OUD increased from 166 in 2000 to 513 in 2019. Compared with discontinuing opioid agonist treatment during pregnancy, continuous opioid agonist treatment reduced odds of preterm birth (adjusted odds ratio: 0.6; 95% confidence interval: 0.4-0.8) and low birth weight (adjusted odds ratio: 0.4; 95% confidence interval: 0.2-0.7). Treatment with buprenorphine-naloxone (compared with methadone) reduced odds of each outcome including neonatal abstinence syndrome (adjusted odds ratio: 0.6; 95% confidence interval: 0.4-0.9).

CONCLUSIONS

Perinatal OUD in British Columbia tripled in incidence over a 20-year period. Sustained opioid agonist treatment during pregnancy reduced the risk of adverse birth outcomes, highlighting the need for expanded services, including opioid agonist treatment to support mothers and infants.

Characterizing opioid agonist treatment discontinuation trends in British Columbia, Canada, 2012-2018

BACKGROUND

Given the elevated risk of mortality immediately following opioid agonist treatment (OAT) discontinuation, determining the frequency and timing of OAT discontinuation can help guide the planning of services to facilitate uninterrupted OAT. We sought to describe weekly and monthly trends in OAT episode discontinuations in British Columbia to determine the potential resource needs for implementing support services.

METHODS

This population-based retrospective study utilized a provincial-level linkage of health administrative databases to identify all people with opioid use disorder (PWOUD) who received OAT between 01/2012-08/2018. We defined OAT episodes as continuous medication dispensations without interruptions in prescribed doses lasting ≥5 days for methadone and ≥6 days for buprenorphine/naloxone. We derived the percentage of PWOUD discontinuing OAT every month and we considered weekly discontinuations between 09/2017-08/2018, accounting for weeks during which monthly income assistance payments from social service programs occurred.

RESULTS

Our study included 37,207 PWOUD discontinuing 158,027 OAT episodes. Discontinuations were relatively stable month-to-month, increasing from 10.6 % to 14.9 % (2012-2018). The monthly percentage of discontinuations was 21.2 % for buprenorphine/naloxone and 10.0 % for methadone. Weekly discontinuations were greater in income disbursement weeks (816; IQR: 752, 901) compared to other weeks (655; IQR: 615, 683; p < 0.01).

CONCLUSIONS

We identified a high, and stable rate of monthly OAT discontinuations and a consistently higher rate of discontinuing treatment among PWOUD accessing buprenorphine/naloxone. There is an urgent need to develop the evidence base for interventions to support OAT engagement and to improve clinical management of OUD to address the opioid-related overdose crisis.

The cascade of care for opioid use disorder among youth in British Columbia, 2018

BACKGROUND

Medication for opioid use disorder (MOUD) is associated with substantial reductions in the risk of mortality, and American and Canadian guidelines recommend it as part of the full range of available treatments for youth with opioid use disorder (OUD). We estimated the OUD cascade of care for all adolescents (ages 12-18) and young adults (19-24) with OUD in British Columbia, Canada (BC) in 2018.

METHODS

Using a provincial-level linkage of six health administrative databases, we classified youth with OUD as adolescents (ages 12-18) or young adults (19-24) to compare with older adults (≥25) and described key factors known to influence engagement in health care. The eight-stage cascade of care included diagnosed with OUD, ever engaged in MOUD, recently in MOUD, currently in MOUD, and retained in MOUD for ≥1 month, ≥3 months, ≥12 months, ≥24 months.

RESULTS

We identified 4048 youth diagnosed with OUD as of September 30, 2018 (6.3% of all people with OUD). Most were young adults, aged 19-24 (n = 3602; 89.0% of all youth), a majority of whom were males (n = 1984; 55.1%). In contrast, adolescents diagnosed with OUD (n = 446; 11.0% of all youth) were mostly females (n = 287; 64.4%). Compared to adolescents, there were more young adults diagnosed with OUD ever engaged in MOUD (71.4% v. 36.5%), currently on MOUD (29.3% v. 16.8%), and retained in care for ≥1 year (8.6% v. 2.0%).

CONCLUSIONS

A high proportion of youth aged 12-24 diagnosed with OUD in a health care setting in British Columbia received MOUD yet continued engagement is infrequent, particularly for adolescents. Long-term treatment plans for youth need to consider including MOUD when appropriate as part of tailored, youth-friendly services.