Impact of Alternative Ways to Operationalize Buprenorphine Treatment Duration on Understanding Continuity of Care for Opioid Use Disorder

The association between buprenorphine doses above 16 milligrams and treatment retention in a multi-payer national sample in the United States, 2014 to 2021

BACKGROUND AND AIMS

Buprenorphine-naloxone reduces overdose deaths in people with opioid use disorder (OUD). Treatment retention increases with higher daily doses. No national studies exist on retention's association with 24, 32 and 40 mg. This study aimed to: (1) estimate the effect on treatment retention of buprenorphine-naloxone doses between 4 and 40 mg compared with 16; and (2) compare the effect on treatment retention of 24, 32 and 40 mg doses.

DESIGN

Observational cohort study in a national, multi-payer sample of prescription claims (IQVIA) of episodes involving buprenorphine-naloxone for OUD. Incident episodes started between 1 January 2014 and 31 March 2020, with a washout of 180 days. New episodes started with a 14+ day gap between prescriptions.

SETTING

United States of America.

PARTICIPANTS

The sample involved 620 229 episodes across 498 879 patients [42.3% female; mean age 37.9 (standard deviaion: 11.9)] who were dispensed prescriptions of buprenorphine-naloxone for OUD.

MEASUREMENTS

The exposure was the maximum daily dose of buprenorphine-naloxone reached in the first 30 days of an episode, ranging from 4 to 40 mg. The outcome, treatment retention, was defined as having an active prescription at 1, 3, 6, 12, or 18 months. Covariates were age, sex, race and ethnicity, primary payer, and year of episode initiation.

FINDINGS

Daily doses of 24, 32 and 40 mg increased retention compared with 16 mg at 1-18 months [adjusted odds ratio (aOR) range = 1.17; 95% confidence interval (CI) = 1.14, 1.20 at 18 months to 1.52 (CI = 1.49, 1.54) at 1 month, both for 24 mg]. In pairwise comparisons, 32 mg was favorable to 24 mg at 6, 12 and 18 months [aOR = 1.06 (95% CI = 1.02, 1.10) at 6 months; aOR = 1.09 (95% CI = 1.04, 1.14) at 12 months; aOR = 1.12 (95% CI = 1.06, 1.19) at 18 months], and 40 mg was favorable to 24 mg at 12 and 18 months [aOR = 1.10 (95% CI = 1.01, 1.21) at 12 months; aOR = 1.18 (95% CI = 1.06, 1.30) at 18 months].

CONCLUSIONS

Daily buprenorphine-naloxone doses of 24 mg appear to be associated with increased treatment retention compared with 16 mg and, for 6+ month episodes, 32 and 40 mg appear to be associated with increased retention compared with 24 mg.

Opioid use disorder Cascade of care: defining a taxonomy for measurement

Background: The opioid use disorder Cascade of care (OUD Cascade) is a public health framework used by federal/state/other agencies and researchers to facilitate monitoring and evaluating responses to the opioid epidemic, including surveillance and performance evaluation. As the use of the framework proliferates, there is an urgent need to standardize stage definitions to accurately monitor and improve patient outcomes and to align interpretation of findings across settings.Objectives: Define a taxonomy to uniformly apply the OUD Cascade to improve delivery of OUD services and better compare patient outcomes across settings and populations.Methods: We conducted a narrative review and synthesis focused on research and guidelines defining and measuring four key OUD Cascade stages: OUD identification, service engagement, medication initiation, and retention. Included articles come from peer-reviewed literature and define and/or operationalize OUD Cascade stages and associated measures across six characteristics based on an adaptation of the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist including: 1) settings, 2) specific population, 3) perspective, 4) time horizon, 5) assumptions, and 6) analytic method.Results: Our review (n = 27 articles) and synthesis provide an overview of how OUD Cascade definitions and framework designs have been variously applied. We found considerable heterogeneity in study approaches for all four OUD Cascade stages. We define a taxonomy to guide future research emphasizing standardized definitions to harmonize efforts across settings. In particular, we emphasize the need for clarity in defining criteria for sample construction (i.e. Identification), clear distinctions between receipt of care services generally (i.e. Engagement) from MOUD Initiation specifically, and Retention definitions that use a 30+ day gap in treatment to define discontinuation.Conclusion: Establishing a shared taxonomy for key terms specifying OUD Cascade stages will help the field advance, compare approaches and results across settings, and improve population-level patient outcomes.

State-level racial and ethnic disparities in buprenorphine treatment duration in the United States

BACKGROUND AND OBJECTIVES

National trends reveal a concerning escalation in racial and ethnic disparities in buprenorphine treatment duration for opioid use disorder. However, the extent of such disparities at the state level remains largely unexplored. This study aims to examine such disparities at the state level.

METHODS

We analyzed 9,040,620 buprenorphine prescriptions dispensed between January 2011 and December 2020 from IQVIA Longitudinal Prescription data. The primary outcome was the difference in median treatment duration between White people and racial and ethnic minorities. We also included a second outcome measurement to quantify the difference in median treatment duration among episodes lasting ≥180 days. Using quantile regressions, we examined racial and ethnic disparities in treatment duration, adjusting for the patient's age, sex, payment type, and calendar year of the treatment episode. All analyses were conducted at the state level.

RESULTS

Our study revealed substantial statewide variations in racial and ethnic disparities. Specifically, 21 states showed longer treatment durations for White people across all episodes, and eight states displayed similar trends among episodes lasting ≥180 days. Five states exhibited longer treatment durations for White people in both overall and long-term episodes. Fifteen states showed no racial and ethnic disparities.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

These results are among the first to indicate substantial statewide variations in racial and ethnic disparities in buprenorphine treatment episode duration, providing a critical foundation for targeted interventions to enhance buprenorphine treatment, especially in states confronting such pronounced racial and ethnic disparities.

Prescription psychostimulant use, admissions and treatment initiation and retention in pregnant people with opioid use disorder

While attention deficit hyperactivity disorder is common among people with addiction, the risks and benefits of attention deficit hyperactivity disorder medication in pregnant people with opioid use disorder are poorly understood. Here, using US multistate administrative data, we examined 3,247 pregnant people initiating opioid use disorder treatment, of whom 5% received psychostimulants. Compared to peers not receiving psychostimulants, the psychostimulant cohort had greater buprenorphine (adjusted relative risk 1.81 (1.50-2.18)) but lower methadone initiation (adjusted relative risk 0.39 (0.19-0.78)). Among psychostimulant recipients who initiated buprenorphine, we observed lower buprenorphine discontinuation associated with the psychostimulant cohort compared to nonrecipients (adjusted hazard ratio 0.77 (0.67-0.88)). In within-person case-crossover analyses, person-days defined by psychostimulant fills were associated with fewer substance use disorder-related admissions compared to days without fills (odds ratio 0.50 (0.33-0.76)). Overall, our data suggest that psychostimulant use in pregnancy may be associated with increased buprenorphine initiation, decreased methadone initiation and improved buprenorphine retention. Decreased substance use disorder-related admissions were associated with person-days of psychostimulant receipt, although other risks of psychostimulant use in pregnancy warrant further investigation.

Medication for Opioid Use Disorder After Serious Injection-Related Infections in Massachusetts

Importance

Serious injection-related infections (SIRIs) cause significant morbidity and mortality. Medication for opioid use disorder (MOUD) improves outcomes but is underused. Understanding MOUD treatment after SIRIs could inform interventions to close this gap.

Objectives

To examine rehospitalization, death rates, and MOUD receipt for individuals with SIRIs and to assess characteristics associated with MOUD receipt.

Design, Setting, and Participants

This retrospective cohort study used the Massachusetts Public Health Data Warehouse, which included all individuals with a claim in the All-Payer Claims Database and is linked to individual-level data from multiple government agencies, to assess individuals aged 18 to 64 years with opioid use disorder and hospitalization for endocarditis, osteomyelitis, epidural abscess, septic arthritis, or bloodstream infection (ie, SIRI) between July 1, 2014, and December 31, 2019. Data analysis was performed from November 2021 to May 2023.

Exposure

Demographic and clinical factors potentially associated with posthospitalization MOUD receipt.

Main Outcomes and Measures

The main outcome was MOUD receipt measured weekly in the 12 months after hospitalization. We used zero-inflated negative binomial regression to examine characteristics associated with any MOUD receipt and rates of treatment in the 12 months after hospitalization. Secondary outcomes were receipt of any buprenorphine formulation, methadone, and extended-release naltrexone examined individually.

Results

Among 8769 individuals (mean [SD] age, 43.2 [12.0] years; 5066 [57.8%] male) who survived a SIRI hospitalization, 4305 (49.1%) received MOUD, 5919 (67.5%) were rehospitalized, and 973 (11.1%) died within 12 months. Of those treated with MOUD in the 12 months after hospitalization, the mean (SD) number of MOUD initiations during follow-up was 3.0 (1.7), with 956 of 4305 individuals (22.2%) receiving treatment at least 80% of the time. MOUD treatment after SIRI hospitalization was significantly associated with MOUD in the prior 6 months (buprenorphine: adjusted odds ratio [AOR], 16.51; 95% CI, 13.81-19.74; methadone: AOR, 28.46; 95% CI, 22.41-36.14; or naltrexone: AOR, 2.05; 95% CI, 1.56-2.69). Prior buprenorphine (incident rate ratio [IRR], 1.17; 95% CI, 1.11-1.24) or methadone (IRR, 1.89; 95% CI, 1.79-2.01) use was associated with higher treatment rates after hospitalization, and prior naltrexone use (IRR, 0.86; 95% CI, 0.77-0.95) was associated with lower rates.

Conclusions and Relevance

This study found that in the year after a SIRI hospitalization in Massachusetts, mortality and rehospitalization were common, and only half of patients received MOUD. Treatment with MOUD before a SIRI was associated with posthospitalization MOUD initiation and time receiving MOUD. Efforts are needed to initiate MOUD treatment during SIRI hospitalizations and subsequently retain patients in treatment.

Treatment setting and buprenorphine discontinuation: an analysis of multi-state insurance claims

BACKGROUND

Potential differences in buprenorphine treatment outcomes across various treatment settings are poorly characterized in multi-state administrative data. We thus evaluated the association of opioid use disorder (OUD) treatment setting and insurance type with risk of buprenorphine discontinuation among commercial insurance and Medicaid enrollees initiated on buprenorphine.

METHODS

In this observational, retrospective cohort study using the Merative MarketScan databases (2006-2016), we analyzed buprenorphine retention in 58,200 US adults with OUD. Predictor variables included insurance status (Medicaid vs commercial) and treatment setting, operationalized as substance use disorder (SUD) specialty treatment facility versus outpatient primary care physicians (PCPs) versus outpatient psychiatry, ascertained by linking physician visit codes to buprenorphine prescriptions. Treatment setting was inferred based on timing of prescriber visit claims preceding prescription fills. We estimated time to buprenorphine discontinuation using multivariable cox regression.

RESULTS

Among enrollees with OUD receiving buprenorphine, 26,168 (45.0%) had prescriptions from SUD facilities without outpatient buprenorphine treatment, with the remaining treated by outpatient PCPs (n = 23,899, 41.1%) and psychiatrists (n = 8133, 13.9%). Overall, 50.6% and 73.3% discontinued treatment at 180 and 365 days respectively. Buprenorphine discontinuation was higher among enrollees receiving prescriptions from SUD facilities (aHR = 1.03[1.01-1.06]) and PCPs (aHR = 1.07[1.05-1.10]). Medicaid enrollees had lower buprenorphine retention than those with commercial insurance, particularly those receiving buprenorphine from SUD facilities and PCPs (aHR = 1.24[1.20-1.29] and aHR = 1.39[1.34-1.45] respectively, relative to comparator group of commercial insurance enrollees receiving buprenorphine from outpatient psychiatry).

CONCLUSION

Buprenorphine discontinuation is high across outpatient PCP, psychiatry, and SUD treatment facility settings, with potentially lower treatment retention among Medicaid enrollees receiving care from SUD facilities and PCPs.

Application of an opioid use disorder cascade of care in a large public health system

Background: Over the past decade, hospitals and health systems have increasingly adopted interventions to address the needs of patients with substance use disorders. The Opioid Use Disorder (OUD) Cascade of Care provides a framework for organizing and tracking patient health milestones over time and can assist health systems in identifying areas of intervention to maximize the impact of evidence-based services. However, detailed protocols are needed to guide health systems in how to operationalize the OUD Cascade and track outcomes using electronic health records.Objective: In this paper, we describe the process of operationalizing and applying the OUD Cascade in a large, urban, public hospital system.Methods: Through this case example, we describe the technical processes around data mining, as well as the decision-making processes, challenges encountered, lessons learned from compiling preliminary patient data and defining stages and outcome measures for the OUD Cascade of Care, and preliminary dataResults: We identified 33,616 (26.17% female) individuals with an OUD diagnosis. Almost half (48%) engaged with addiction services, while only 10.7% initiated medication-based treatment in an outpatient setting, 6.7% had timely follow-up, and 3.5% were retained for a minimum of 6 months.Conclusion: The current paper serves as a primer for other health systems seeking to implement data-informed approaches to guide more efficient care and improved substance use-related outcomes. An OUD Cascade of Care must be tailored to local systems based on inherent data limitations and services design with an emphasis on early stages wherein drop-off is the greatest.

Co-occurring psychiatric disorders and disparities in buprenorphine utilization in opioid use disorder: An analysis of insurance claims

Background

As the overdose crisis continues in the U.S. and Canada, opioid use disorder (OUD) treatment outcomes for people with co-occurring psychiatric disorders are not well characterized. Our objective was to examine the influence of co-occurring psychiatric disorders on buprenorphine initiation and discontinuation.

Methods

This retrospective cohort study used multi-state administrative claims data in the U.S. to evaluate rates of buprenorphine initiation (relative to psychosocial treatment without medication) in a cohort of 236,198 people with OUD entering treatment, both with and without co-occurring psychiatric disorders, grouping by psychiatric disorder subtype (mood, psychotic, and anxiety-and-related disorders). Among people initiating buprenorphine, we assessed the influence of co-occurring psychiatric disorders on buprenorphine retention. We used multivariable Poisson regression to estimate buprenorphine initiation and Cox regression to estimate time to discontinuation, adjusting for all 3 classes of co-occurring disorders simultaneously and adjusting for baseline demographic and clinical characteristics.

Results

Buprenorphine initiation occurred in 29.3 % of those with co-occurring anxiety-and-related disorders, compared to 25.9 % and 17.5 % in people with mood and psychotic disorders. Mood (adjusted-risk-ratio[aRR] = 0.82[95 % CI = 0.82-0.83]) and psychotic disorders (aRR = 0.95[0.94-0.96]) were associated with decreased initiation (versus psychosocial treatment), in contrast to greater initiation in the anxiety disorders cohort (aRR = 1.06[1.05-1.06]). We observed an increase in buprenorphine discontinuation associated with mood (adjusted-hazard-ratio[aHR] = 1.20[1.17-1.24]) and anxiety disorders (aHR = 1.12[1.09-1.14]), in contrast to no association between psychotic disorders and buprenorphine discontinuation.

Conclusions

We observed underutilization of buprenorphine among people with co-occurring mood and psychotic disorders, as well as high buprenorphine discontinuation across anxiety, mood, and psychotic disorders.

Gabapentin Use Among Individuals Initiating Buprenorphine Treatment for Opioid Use Disorder

Importance

Gabapentin prescriptions have drastically increased in the US due to off-label prescribing in settings such as opioid use disorder (OUD) treatment to manage a range of comorbid conditions and withdrawal symptoms, despite a lack of evidence.

Objective

To assess the purpose and associated risks of off-label gabapentin use in OUD treatment.

Design, Setting, and Participants

This retrospective recurrent-event case-control study with a crossover design used administrative claims data from MarketScan Commercial and Multi-State Medicaid databases from January 1, 2006, to December 31, 2016. Individuals aged 12 to 64 years with an OUD diagnosis and filling buprenorphine prescriptions were included in the primary analysis conducted from July 1, 2022, through June 1, 2023. Unit of observation was the person-day.

Exposures

Days covered by filled gabapentin prescriptions.

Main Outcomes and Measures

Primary outcomes were receipt of gabapentin in the 90 days after initiation of buprenorphine treatment and drug-related poisoning. Drug-related poisonings were defined using codes from International Classification of Diseases, Ninth Revision, and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision.

Results

A total of 109 407 patients were included in the analysis (mean [SD] age, 34.0 [11.2] years; 60 112 [54.9%] male). Among the 29 967 patients with Medicaid coverage, 299 (1.0%) were Hispanic, 1330 (4.4%) were non-Hispanic Black, 23 112 (77.1%) were non-Hispanic White, and 3399 (11.3%) were other. Gabapentin was significantly less likely to be prescribed to Black or Hispanic patients, and more likely to be prescribed to female patients, those with co-occurring substance use or mood disorders, and those with comorbid physical conditions such as neuropathic pain. Nearly one-third of persons who received gabapentin (4336 [31.1%]) had at least 1 drug-related poisoning after initiating buprenorphine treatment, compared with 13 856 (14.5%) among persons who did not receive gabapentin. Adjusted analyses showed that days of gabapentin use were not associated with hospitalization for drug-related poisoning (odds ratio, 0.98 [95% CI, 0.85-1.13]). Drug-related poisoning risks did not vary based on dosage.

Conclusions and Relevance

Gabapentin is prescribed in the context of a myriad of comorbid conditions. Even though persons receiving gabapentin are more likely to have admissions for drug-related poisoning, these data suggest that gabapentin is not associated with an increased risk of drug-related poisoning alongside buprenorphine in adjusted analyses. More data on the safety profile of gabapentin in OUD settings are needed.

Racial and Ethnic Inequities in Buprenorphine and Methadone Utilization Among Reproductive-Age Women with Opioid Use Disorder: an Analysis of Multi-state Medicaid Claims in the USA

BACKGROUND

Associations between race/ethnicity and medications to treat OUD (MOUD), buprenorphine and methadone, in reproductive-age women have not been thoroughly studied in multi-state samples.

OBJECTIVE

To evaluate racial/ethnic variation in buprenorphine and methadone receipt and retention in a multi-state U.S. sample of Medicaid-enrolled, reproductive-age women with opioid use disorder (OUD) at the beginning of OUD treatment.

DESIGN

Retrospective cohort study.

SUBJECTS

Reproductive-age (18-45 years) women with OUD, in the Merative™ MarketScan® Multi-State Medicaid Database (2011-2016).

MAIN MEASURES

Differences by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, "other" race/ethnicity) in the likelihood of receiving buprenorphine and methadone during the start of OUD treatment (yes/no) were estimated using multivariable logistic regression. Differences in time to medication discontinuation (days) by race/ethnicity were evaluated using multivariable Cox regression.

RESULTS

Of 66,550 reproductive-age Medicaid enrollees with OUD (84.1% non-Hispanic White, 5.9% non-Hispanic Black, 1.0% Hispanic, 5.3% "other"), 15,313 (23.0%) received buprenorphine and 6290 (9.5%) methadone. Non-Hispanic Black enrollees were less likely to receive buprenorphine (adjusted odds ratio, aOR = 0.76 [0.68-0.84]) and more likely to be referred to methadone clinics (aOR = 1.78 [1.60-2.00]) compared to non-Hispanic White participants. Across both buprenorphine and methadone in unadjusted analyses, the median discontinuation time for non-Hispanic Black enrollees was 123 days compared to 132 days and 141 days for non-Hispanic White and Hispanic enrollees respectively (χ2 = 10.6; P = .01). In adjusted analyses, non-Hispanic Black enrollees experienced greater discontinuation for buprenorphine and methadone (adjusted hazard ratio, aHR = 1.16 [1.08-1.24] and aHR = 1.16 [1.07-1.30] respectively) compared to non-Hispanic White peers. We did not observe differences in buprenorphine or methadone receipt or retention for Hispanic enrollees compared to the non-Hispanic White enrollees.

CONCLUSIONS

Our data illustrate inequities between non-Hispanic Black and non-Hispanic White Medicaid enrollees with regard to buprenorphine and methadone utilization in the USA, consistent with literature on the racialized origins of methadone and buprenorphine treatment.

Application of an Opioid Use Disorder Cascade of Care in a Large Public Health System

Background

Over the past decade, hospitals and health systems have increasingly adopted interventions to address the needs of patients with substance use disorders. The Opioid Use Disorder (OUD) Cascade of Care provides a framework for organizing and tracking patient health milestones over time, and can assist health systems in identifying areas of intervention to prevent overdose and maximize the impact of evidence-based services for patients with OUD. However, detailed protocols are needed to guide health systems in how to operationalize the OUD Cascade and track outcomes using their systems' electronic medical records (EMR).

Objective

In this paper, we describe the process of operationalizing and implementing the OUD Cascade in one large, urban, public hospital system.

Methods

Through this case example, we describe the technical processes around data mining, as well as the decision-making processes, challenges encountered, and lessons learned from compiling patient data and defining stages and outcome measures for the OUD Cascade of Care. The current established framework and process will set the stage for subsequent research studies that quantify and evaluate patient progression through each stage of OUD treatment across the health system and identify target areas for quality improvement initiatives to better engage patients in care and improve health outcomes.

Results

The current paper can therefore serve as a primer for other health systems seeking to implement a data-informed approach to guide more efficient care and improved substance use-related outcomes.

Conclusion

An OUD Cascade of Care must be tailored to local systems based on inherent data limitations and services design.

Measuring time in buprenorphine treatment stages among people with HIV and opioid use disorder by retention definition and its association with cocaine and hazardous alcohol use

BACKGROUND

We use a novel, longitudinal approach to describe average time spent in opioid use disorder (OUD) cascade of care stages for people with HIV (PWH) and with OUD, incorporating four definitions of treatment retention. Using this approach, we describe the impact of cocaine or hazardous alcohol use on time spent retained on buprenorphine.

METHODS

We followed PWH with OUD enrolled in the Johns Hopkins HIV Clinical Cohort from their first buprenorphine treatment episode between 2013 and 2020. We estimated 4-year restricted mean time spent on buprenorphine below buprenorphine retention threshold, on buprenorphine above retention threshold, off buprenorphine and in HIV care, loss to follow-up, and death. Retention definitions were based on retention threshold (180 vs 90 days) and allowable treatment gap (7 vs 30 days). Differences in 2-year restricted mean time spent retained on buprenorphine were estimated for patients with and without cocaine or hazardous alcohol use.

RESULTS

The study sample (N = 179) was 63% male, 82% non-Hispanic Black, and mean age was 53 (SD 8) years. Patients spent on average 13.9 months (95% CI 11.4, 16.4) on buprenorphine over 4 years. There were differences in time spent retained on buprenorphine based on the retention definition, ranging from 6.5 months (95% CI 4.6, 8.5) to 9.6 months (95% CI 7.4, 11.8). Patients with cocaine use spent fewer months retained on buprenorphine. There were no differences for patients with hazardous alcohol use.

CONCLUSIONS

PWH with OUD spend relatively little time receiving buprenorphine in their HIV primary care clinic. Concurrent cocaine use at buprenorphine initiation negatively impact time on buprenorphine.

Prescription amphetamines in people with opioid use disorder and co-occurring psychostimulant use disorder initiating buprenorphine: an analysis of treatment retention and overdose risk

BACKGROUND

Attention-deficit and hyperactivity disorder (ADHD) is frequently diagnosed in patients with substance use disorders (SUDs), including opioids. There remains concern about the safety and efficacy of prescription amphetamines (PAs) and their impact on effectiveness of opioid use disorder (OUD) treatment with buprenorphine.

OBJECTIVES

To assess the effect of PAs on OUD buprenorphine treatment retention and/or SUD-related emergency admission or drug-related poisonings.

METHODS

We used a retrospective cohort design with a secondary analysis of data from Merative MarketScan Commercial and Multi-State Medicaid Databases from 1 January 2006 to 31 December 2016. Individuals included were aged 12-64 years, had an OUD diagnosis and were prescribed buprenorphine. Our analysis used multivariable Cox regression to evaluate the relationship between PA receipt and time to buprenorphine discontinuation. The second part focused on subsamples of buprenorphine initiators who had either (1) any SUD-related emergency admissions or (2) drug-related poisoning. These outcomes were modelled as a function of PA exposure using conditional logistic regression models as part of a within-person, case-crossover design.

FINDINGS

Our sample had 90 269 patients with OUD (mean age 34.2 years (SD=11.3)) who initiated buprenorphine. Being prescribed a PA was associated with improved buprenorphine retention among individuals both with (adjusted HR (aHR) 0.91 (95% CI 0.86 to 0.97)) and without a concurrent psychostimulant use disorder (PSUD) (aHR 0.92 (95% CI 0.90 to 0.93)).

CONCLUSIONS

PA use was associated with improved buprenorphine retention in people with OUD with and without co-occurring PSUD. The risks of acute SUD-related events and drug-related poisonings associated with PA use did not differ when comparing PA-using days with days without PA use.

CLINICAL IMPLICATIONS

Patients with OUD on buprenorphine should receive treatment with a PA when indicated.