Data-driven strategies for increasing patient diversity in Bristol Myers Squibb-sponsored US oncology clinical trials.

BACKGROUND/AIMS: Determining whether clinical trial findings are applicable to diverse, real-world patient populations can be challenging when the full demographic characteristics of enrolled patients are not consistently reported. Here, we present the results of a descriptive analysis of racial and ethnic demographic information for patients in Bristol Myers Squibb (BMS)-sponsored oncology trials in the United States (US) and describe factors associated with increased patient diversity. METHODS: BMS-sponsored oncology trials conducted at US sites with study enrollment dates between 1 January 2013 and 31 May 2021 were analyzed. Patient race/ethnicity information was self-reported in case report forms. As principal investigators (PIs) did not report their own race/ethnicity, a deep-learning algorithm (ethnicolr) was used to predict PI race/ethnicity. Trial sites were linked to counties to understand the role of county-level demographics. The impact of working with patient advocacy and community-based organizations to increase diversity in prostate cancer trials was analyzed. The magnitude of associations between patient diversity and PI diversity, US county demographics, and recruitment interventions in prostate cancer trials were assessed by bootstrapping. RESULTS: A total of 108 trials for solid tumors were analyzed, including 15,763 patients with race/ethnicity information and 834 unique PIs. Of the 15,763 patients, 13,968 (89%) self-reported as White, 956 (6%) Black, 466 (3%) Asian, and 373 (2%) Hispanic. Among 834 PIs, 607 (73%) were predicted to be White, 17 (2%) Black, 161 (19%) Asian, and 49 (6%) Hispanic. A positive concordance was observed between Hispanic patients and PIs (mean = 5.9%; 95% confidence interval (CI) = 2.4, 8.9), a less positive concordance between Black patients and PIs (mean = 1.0%; 95% CI = -2.7, 5.5), and no concordance between Asian patients and PIs. Geographic analyses showed that more non-White patients enrolled in study sites in counties with higher proportions of non-White residents (e.g. a county population that was 5%-30% Black had 7%-14% more Black patients enrolled in study sites). Following purposeful recruitment efforts in prostate cancer trials, 11% (95% CI = 7.7, 15.3) more Black men enrolled in prostate cancer trials. CONCLUSION: Most patients in these clinical trials were White. PI diversity, geographic diversity, and recruitment efforts were related to greater patient diversity. This report constitutes an essential step in benchmarking patient diversity in BMS US oncology trials and enables BMS to understand which initiatives may increase patient diversity. While complete reporting of patient characteristics such as race/ethnicity is critical, identifying diversity improvement tactics with the highest impact is essential. Strategies with the greatest concordance to clinical trial patient diversity should be implemented to make meaningful improvements to the diversity of clinical trial populations.

Multimorbidity in patients attending 2 Australian primary care practices.

PURPOSE: Multiple chronic conditions in a single patient can be a challenging health burden. We aimed to examine patterns and prevalence of multimorbidity among patients attending 2 large Australian primary care practices and to estimate disease severity burden using the Cumulative Illness Rating Scale (CIRS). METHODS: Using published CIRS guidelines and a disease severity index calculated for each individual, we extracted data from the medical records of all 7,247 patients (58.5% female) seen over 6 months in 2008 who were rated for chronic conditions across 14 anatomical domains. RESULTS: Fifty-two percent of patients had multimorbidity in 2 or more CIRS domains, ranging from 20.6% if younger than 25 years, 43.7% if aged 25 to 44 years, 75.5% if aged 45 to 64 years, 87.5% if aged 65 to 74 years, and 97.1% if aged 75 years and older. Using a cutoff of 3 or more CIRS domains, 34.5% had multimorbidity ranging from 4.8% if younger than 25 years, 22.3% if aged 25 to 44 years, 56.1% if aged 45 to 64 years, 74.6% if aged 65 to 74 years, and 92.0% if aged 75 years and older. Musculoskeletal, singularly or in combination with others, was the commonest morbidity domain. The moderate severity index category increased with increasing age. CONCLUSIONS: Multimorbidity is a significant problem in men and women across all age-groups, and the moderate severity index increases with age. The musculoskeletal domain was most commonly affected. Mild and moderate severity index categories may underrepresent disease burden. Severity burden assessment in the primary care setting needs to take into account the severity index, as well as levels of domain severity within the index categories.

Perceptions of barriers to discussing and testing for sexually transmitted infections in a convenience sample of general practice patients.

We aimed to identify patient perceptions of barriers to discussing sexually transmitted infections (STIs) at the primary care level. An anonymous questionnaire was available to patients (16-70 years) in the waiting room of four metropolitan Perth general practices. Results are based on 370 participant views (9.5% of the potential target population). Patients felt comfortable discussing STIs with their general practitioner (GP) and their level of comfort would be enhanced if they knew their GP had a special interest or qualification in sexual health. Willingness to discuss issues increased or remained unchanged if the GP took time to explain it to them or was a good listener. Patients were willing to discuss STIs if they were a new patient and irrespective of the GP's gender and age. Fewer patients were willing to discuss STIs if they knew the GP socially. Patients who had sex with a new partner were willing to request a STI test from their GP. Patients were not embarrassed if discussion was initiated in a consultation unrelated to sexual health and did not mind discussing the topic in the presence of a partner or parent, though this depended on circumstances. Waiting room STI test advertising did not affect patient comfort level. Patients would involve their GP when seeking information about STIs. Patients have fewer barriers to discussing sexual health matters than perceived by GPs.

Disruption caused by the COVID-19 pandemic response from a Western Australian metropolitan general practice perspective: a qualitative descriptive study.

BACKGROUND: In 2020 and 2021, Western Australia (WA) was an early adopter of the 'COVID zero' policy, eliminating community transmission and pursuing vaccine roll out to enable a 'soft landing' once coronavirus disease 2019 (COVID-19) infiltrated the community in 2022. Optimisation and augmentation of general practice services were at the forefront of policies. This study explores metropolitan general practice responses to the resulting disruption caused. METHODS: Qualitative descriptive methodology, purposive sampling and template analysis were used. Semi-structured interviews were undertaken from March to June 2021 with teams from six general practices in metropolitan WA; six general practitioners, four practice nurses and three practice managers. RESULTS: Staff at all levels responded rapidly amid uncertainty and workload challenges with marked personal toll (anxiety and fear of exposure to risks, frustrations of patients and balancing work and family life). Self-reliance, teamwork and communication strategies built on inclusivity, autonomy and support were important. Responding to changes in general patient behaviour was to the fore. Increasing use of telehealth (telephone and video) became important to meet patient needs. Lessons learned from what was implemented in early-stage lockdowns provided practices with preparedness for the future, and smoother transitions during subsequent lockdowns. CONCLUSION: The study demonstrates the self-reliance, teamwork and adaptability of the general practice sector in responding to a sudden, unexpected major disruption, yet maintaining ongoing service provision for their patients. Although the COVID-19 landscape has now changed, the lessons learned and the planning that took place will help general practice in WA adapt to similar future situations readily.

Challenges to Provision of Adequate Medical Nutrition Therapy in a Critically Ill COVID-19 Patient Fed in the Prone Position.

Adults with acute respiratory distress syndrome (ARDS) may experience enteral nutrition (EN) intolerance. They often require mechanical ventilation and other specialized management including prone positioning. There is a controversy as to whether patients fed in prone position experience more EN intolerance than when they are in supine position. This narrative review synthesizes the literature published between 2001 and 2021 in adults with ARDS who are fed EN while in the prone position to determine safety and tolerance. A case of an adult patient with Down syndrome who developed ARDS due to COVID-19 and required EN while in prone position is presented.

Participant experiences of intervention to detect and manage familial hypercholesterolaemia in Australian general practice: A qualitative descriptive study.

BACKGROUND AND OBJECTIVES: General practitioners (GPs) are ideally placed to have a much larger role in detection and management of familial hypercholesterolaemia (FH) among their patients. The aim of this study was to seek the reflections of practice staff and newly diagnosed patients with FH on the implementation of an FH model of care in the general practice setting. METHOD: Qualitative descriptive methodology was used. Interviews were conducted with 36 practice staff and 51 patients from 15 practices participating in the study. RESULTS: Data were analysed thematically and coded into themes - efficacy of GP training, screening for FH, model of care, patient awareness and cascade testing. DISCUSSION: Findings reflect the real-world clinical experience of Australian general practice and the acceptability of the model of care for both patients with FH and practice staff. Patient health literacy is a barrier to both management of FH and cascade testing. A systematic approach to cascade testing is required.

Cost impact of undertaking detection and management of familial hypercholesterolaemia in Australian general practice.

BACKGROUND AND OBJECTIVES: Familial hypercholesterolaemia (FH) can be effectively detected and managed in primary care, but the health economic evidence for this is scarce. The aim of this study was to examine management pathways and cost implications of FH screening and management in Australian general practice. METHOD: Cost-effectiveness outcomes were projected using a life table model. Data was used from 133 patients in 15 Australian general practice clinics from an earlier screening and management study. Costing and mortality data were sourced from governmental sources and published literature. RESULTS: Most patients had a regular general practice consultation at baseline (82%), though the proportion seen under a chronic disease management item at follow-up increased to 23%. The median cost of management was $275 per annum in the first year of management. Managing patients with statins up to the age of 60 years yielded an increase of 248,954 life-years at a cost of $759 million, representing a cost per life-year gained of $3047. DISCUSSION: Screening and management of FH in general practice has the potential for substantial health benefits while requiring relatively modest investments from the health system.

Clinical response and tolerability to abatacept in patients with rheumatoid arthritis previously treated with infliximab or abatacept: open-label extension of the ATTEST Study.

OBJECTIVE: To assess the efficacy and safety of abatacept in biological-naive patients with rheumatoid arthritis and an inadequate response to methotrexate treated in the long-term extension (LTE) of the ATTEST trial. METHODS: Patients randomly assigned to abatacept, placebo or infliximab completing the 1-year double-blind period were eligible to receive abatacept ∼10 mg/kg in the open-label LTE. Efficacy to year 2 is presented for patients randomly assigned to abatacept or infliximab who switched to open-label abatacept. Safety data are presented for all patients entering LTE regardless of double-blind treatment. RESULTS: Of 431 patients randomly assigned, 79.8% remained on abatacept at year 2. At years 1 and 2, 19.7% and 26.1% of abatacept and 13.3% and 28.6% of infliximab-to-abatacept patients achieved disease activity score 28-defined remission (<2.6). Safety with abatacept during the cumulative study period was consistent with the double-blind experience, with no increase in adverse event incidence following the switch to abatacept. CONCLUSION: In methotrexate-inadequate responders, abatacept efficacy was maintained over 2 years. For infliximab-to-abatacept patients, efficacy improvements were seen in year 2 after patients switched to abatacept. Switching directly from infliximab to abatacept was well tolerated. These data demonstrate that abatacept provides sustained responses and consistent safety, suggesting that switching from infliximab to abatacept is a viable treatment option.

Capacity census - a pilot study of general practices in Western Australia.

The GP Super Clinics that will provide multidisciplinary primary care services are seen as a key feature of the Federal Government's health infrastructure development. They are designed to improve convenience for patients when accessing services ­ especially patients with multiple comorbidities requiring visits to multiple providers ­ as well as providing the space and equipment for teaching and research in primary care. In addition, Medicare Locals are seen as facilitating 'investments in primary healthcare infrastructure, including GP Super Clinics'. Enhancements to existing private general practices to 'support a broader team, teaching or visiting sessions from other health professionals' are also seen as infrastructure development possibilities. Although no one model is provided for GP Super Clinics, it is intended that each 'will bring together general practitioners, nurses, visiting medical specialists, allied health professionals and other healthcare providers to deliver better healthcare, tailored to the needs and priorities of the local community'.

Awareness of familial hypercholesterolaemia in Australian primary care: A qualitative descriptive study.

BACKGROUND AND OBJECTIVES: A lack of public and health professional awareness about familial hypercholesterolaemia (FH) leads to an estimated 90,000 Australians remaining undiagnosed. The aim of this study was to establish the level of knowledge and awareness of FH in Australian general practices. METHOD: A qualitative descriptive methodology was used to explore baseline knowledge and perceptions of practice staff about diagnosing and managing FH. Overall, 63 interviews were conducted with general practice staff at 15 practices taking part in a National Health and Medical Research Council partnership grant study (GNT1142883). RESULTS: Data were analysed thematically and coded into themes - knowledge/awareness/recall, management, use of guidelines/referrals, and contacting family members. Most general practitioners treated the high cholesterol component as their primary focus. Guidelines and referrals were rarely used. DISCUSSION: This research reflected a lack of knowledge, awareness and use of guidelines similar to that shown in other published studies. Improved primary care infrastructure, knowledge and awareness of FH need to be addressed.

Improving detection and management of familial hypercholesterolaemia in Australian general practice.

OBJECTIVE: Familial hypercholesterolaemia (FH) is characterised by elevated low-density lipoprotein (LDL)-cholesterol and increased risk of cardiovascular disease. However, FH remains substantially underdiagnosed and undertreated. We employed a two-stage pragmatic approach to identify and manage patients with FH in primary healthcare. METHODS: Medical records for 232 139 patients who attended 15 general practices at least once in the previous 2 years across five Australian States were first screened for potential risk of FH using an electronic tool (TARB-Ex) and confirmed by general practitioner (GP) clinical assessment based on phenotypic Dutch Lipid Clinic Network Criteria (DLCNC) score. Follow-up GP consultation and management was provided for patients with phenotypic FH. RESULTS: A total of 1843 patients were identified by TARB-Ex as at potential risk of FH (DLCNC score ≥5). After GP medical record review, 900 of these patients (49%) were confirmed with DLCNC score ≥5 and classified as high-risk of FH. From 556 patients subsequently clinically assessed by GPs, 147 (26%) were diagnosed with phenotypic FH (DLCNC score >6). Follow-up GP consultation and management for 77 patients resulted in a significant reduction in LDL-cholesterol (-16%, p<0.01). A higher proportion of these patients attained the treatment target of 50% reduction in LDL-cholesterol (74% vs 62%, p<0.001) and absolute levels of LDL-cholesterol goals compared with baseline (26% vs 12%, p<0.05). CONCLUSIONS: A pragmatic approach integrating electronic medical record tools and clinical GP follow-up consultation is a feasible method to identify and better manage patients with FH in the primary healthcare setting. TRIAL REGISTRATION NUMBER: 12616000630415.

Opportunistic screening for chlamydia in young men.

BACKGROUND: Information on prevalence of genital Chlamydia trachomatis in young men attending Australian general practices is scarce. OBJECTIVE: We aimed to estimate the prevalence of chlamydia in this group; establish behaviours associated with infection, and evaluate general practitioner follow up of positive cases. METHODS: Sexually active men (aged 15-29 years) attending 10 general practices in Perth, Western Australia, were tested for chlamydia and completed a self report questionnaire concerning sexual practices and symptoms. RESULTS: Prevalence of chlamydia was 3.7% (95% CI: 2-6%, n=14/383). High rates of risky sexual practices were observed in both chlamydia positive and negative participants. The association between chlamydia status and risky sexual practices however, was not statistically significant. Treatment and notification of positive cases were usually undertaken, but GPs did not always check that patients had contacted sexual partners. CONCLUSION: We found little relationship between reported sexual behaviour and chlamydia infection in young men. It may be appropriate to offer screening to all at risk individuals.

Biodegradability of naltrexone-poly(DL) lactide implants in vivo assessed under ultrasound in humans.

Ultrasound was used to assess the in vivo biodegradability of a sustained release poly(DL)lactide naltrexone implant in 71 persons previously treated for heroin dependence. We assessed 139 implant sites ranging from 2 to 1808 days post implant. Ultrasound assessment showed that implant tablets were initially well demarcated from each other and from the surrounding tissues. Biodegradation resulted in less demarcated tablets followed by clumping into a single mass-like structure. This mass subsequently dispersed by approximately 1201 days post implant with no implant material visualized by ultrasound. The biodegradation was also assessed by visual clinical examination and palpation of the implant site as well as patient self-report. These measures were generally well correlated with ultrasound results. Clinical assessment of the biodegradation process concluded that the implant changed from 'firm' to 'less firm' and from 'initial square edge' to 'rounded edge' tablets. Collectively, these data provide direct evidence of the in vivo absorption of the Go Medical implant over time, and its biodegradability in humans.

A general practice street health service: Patient and allied service provider perspectives

DISCUSSION: People who are homeless or marginalised have poor engagement with mainstream healthcare services. The aim of this study was to explore patient and staff perspectives of a street-based, primary health service, to help identify factors influencing patient access and management. A qualitative study was undertaken from April to September 2016. Interviews (n = 27) explored patients' experiences of accessing healthcare services. Interviews with allied service staff (n = 5) explored referral pathways and patients' access to healthcare.  Factors influencing patients' willingness to access primary healthcare through the street health service were identified as doctor­patient empathy, better understanding of patient circumstances, fostering of social capital, facilitating referral pathways and supporting the transition to mainstream general practice as circumstances improve. Hospital discharge planning and follow-up management were identified as gaps in the continuity of service. Ease of access provided by a street-based health service facilitates access to the healthcare system for homeless and marginalised patients. 

Increasing multimorbidity in an Australian street health service: A 10-year retrospective cohort study

Background and objectives: Street-based clinics provide general practice services to marginalised and homeless persons. The objective of this study was to examine prevalence, patterns and severity of multimorbidity in patients attending one such service. Method: A retrospective cohort study (2006­15), comprising medical record review of patients (n = 4285), was undertaken. A Cumulative Illness Rating Scale (CIRS) was used to assess multimorbidity. Results: Average age of patients was 38.2 ± 17.9 years. Of 31.5% Aboriginal patients, 50.8% were female (37.6% in non Aboriginal patients). Of all patients, 53% had multimorbidity. Aboriginal patients had higher rates of multimorbidity than non-Aboriginal patients (58.0% vs 50.6%, P <0.001). Psychiatric, musculoskeletal (especially skin) and respiratory conditions were most common. Disease severity was mild to moderate, with 26.8% having at least one severe or extremely severe condition. Multimorbidity and disease severity increased between 2006­11 and 2012­15. Aboriginality was the strongest predictor of multimorbidity (odds ratio [OR] = 2.1; 95% confidence interval [CI]: 1.8­2.4; P <0.001). Discussion: Street-based general practice services are critical to facilitate easy access to primary and secondary management of chronic multimorbid conditions in marginalised (especially Aboriginal) patients.

Mental health outcomes following naltrexone implant treatment for heroin-dependence.

BACKGROUND: Oral naltrexone is an approved treatment for opioid dependence. However, the impact of sustained release naltrexone on the mental health of treated opioid users has not been studied. AIMS: To assess if naltrexone via implant treatment was associated with any change in (i) risk, (ii) rate, and (iii) duration for hospital morbidity related to several categories of mental disorders among treated heroin users. METHOD: A cohort of 359 heroin users treated with sustained release naltrexone via implants in Western Australia was retrospectively followed up for mental health related outcomes via a health record linkage system over an average period of 1.78 years post-treatment. RESULTS: Individual patient's risk for hospital mental diagnoses was not altered after naltrexone implant. On a population cohort level, hospital admission rates related to all mental health problems, except mood disorders, declined significantly post-treatment; however, length of hospital stay did not improve. Overall, young, female patients or those with pre-existing mental illness were more likely than other patients to require hospital care for mental health issues following treatment. Longer period of heroin use was associated with poorer mood outcomes. CONCLUSIONS: Naltrexone implants were not associated with an increased risk for hospitalisation due to mental illness, and in most cases, were associated with a decrease in mental related hospital admission rate.

Detection and management of familial hypercholesterolaemia in primary care in Australia: protocol for a pragmatic cluster intervention study with pre-post intervention comparisons.

INTRODUCTION: Familial hypercholesterolaemia (FH), an autosomal dominant disorder of lipid metabolism, results in accelerated onset of atherosclerosis if left untreated. Lifelong treatment with diet, lifestyle modifications and statins enable a normal lifespan for most patients. Early diagnosis is critical. This protocol trials a primary care-based model of care (MoC) to improve detection and management of FH. METHODS AND ANALYSIS: Pragmatic cluster intervention study with pre-post intervention comparisons in Australian general practices. At study baseline, current FH detection practice is assessed. Medical records over 2 years are electronically scanned using a data extraction tool (TARB-Ex) to identify patients at increased risk. High-risk patients are clinically reviewed to provide definitive, phenotypic diagnosis using Dutch Lipid Clinic Network Criteria. Once an index family member with FH is identified, the primary care team undertake cascade testing of first-degree relatives to identify other patients with FH. Management guidance based on disease complexity is provided to the primary care team. Study follow-up to 12 months with TARB-Ex rerun to identify total number of new FH cases diagnosed over study period (via TARB-Ex, cascade testing and new cases presenting). At study conclusion, patient and clinical staff perceptions of enablers/barriers and suggested improvements to the approach will be examined. Resources at each stage will be traced to determine the economic implications of implementing the MoC and costed from health system perspective. Primary outcomes: increase in number of index cases clinically identified; reduction in low-density lipoprotein cholesterol of treated cases. SECONDARY OUTCOMES: increase in the number of family cases detected/contacted; cost implications of the MoC. ETHICS AND DISSEMINATION: Study approval by The University of Notre Dame Australia Human Research Ethics Committee Protocol ID: 0 16 067F. Registration: Australian New Zealand Clinical Trials Registry ID: 12616000630415. Information will be disseminated via research seminars, conference presentations, journal articles, media releases and community forums. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry ID 12616000630415; Pre-results.

A new electronic screening tool for identifying risk of familial hypercholesterolaemia in general practice.

OBJECTIVE: To evaluate the performance of a new electronic screening tool (TARB-Ex) in detecting general practice patients at potential risk of familial hypercholesterolaemia (FH). METHODS: Medical records for all active patients seen between 2012 and 2014 (n=3708) at a large general practice in Perth, Western Australia were retrospectively screened for potential FH risk using TARB-Ex. Electronic extracts of medical records for patients identified with potential FH risk (defined as Dutch Lipid Clinic Network Criteria (DLCNC) score ≥5) through TARB-Ex were reviewed by a general practitioner (GP) and lipid specialist. High-risk patients were recalled for clinical assessment to determine phenotypic FH diagnosis. Performance was evaluated against a manual record review by a GP in the subset of 360 patients with high blood cholesterol (cholesterol ≥7 mmol/L or low-density lipoprotein cholesterol ≥4.0 mmol/L). RESULTS: Thirty-two patients with DLCNC score ≥5 were identified through electronic screening compared with 22 through GP manual review. Sensitivity was 95.5% (95% CI 77.2% to 99.9%), specificity was 96.7% (95% CI 94.3% to 98.3%), negative predictive accuracy was 99.7% (95% CI 98.3% to 100%) and positive predictive accuracy was 65.6% (95% CI 46.9% to 8%). Electronic screening was completed in 10 min compared with 60 h for GP manual review. 10 of 32 patients (31%) were considered high risk and recalled for clinical assessment. Six of seven patients (86%) who attended clinical assessment were diagnosed with phenotypic FH on examination. CONCLUSIONS: TARB-Ex screening is a time-effective and cost-effective method of systematically identifying potential FH risk patients from general practice records for clinical follow-up.

Reducing hospital presentations for opioid overdose in patients treated with sustained release naltrexone implants.

BACKGROUND: Non-fatal overdoses represent a significant morbidity for regular heroin users. Naltrexone is an opioid antagonist capable of blocking the effects of heroin, thereby preventing accidental overdose. However, treatment with oral naltrexone is often associated with non-compliance. An alternative is the use of a sustained release preparation of naltrexone. The aim of this study was to assess the change in number of opioid and other drug overdoses in a large cohort of heroin dependent persons (n=361; 218 males) before and after treatment with a sustained release naltrexone implant. A sub-group of this cohort (n=146; 83 males) had previously received treatment with oral naltrexone, which also allowed a comparison of overdoses pre- and post-oral and also post-implant treatments. METHOD: We used a pre-post design, with data prospectively collected via the West Australian Health Services Research Linked Database, and the Emergency Department Information System. Participants were treated under the Australian Therapeutic Goods Administration's special access guidelines. RESULTS: Most (336, 93%) of the cohort was in one or both databases. We identified 21 opioid overdoses involving 20 persons in the 6 months pre-treatment that required emergency department presentation or hospital admission: none were observed in the 6 months post-treatment. This is consistent with the existing pharmacokinetic data on this implant, which indicates maintenance of blood naltrexone levels at or above 2 ng/ml for approximately 6 months. A reduced number of opioid overdoses were also observed 7-12 months post-implant. The study found a significant increase in sedative "overdoses", some of which occurred in the 10 days following implant treatment and were likely associated with opioid withdrawal and/or implant treatment. For those previously treated with oral naltrexone, more opioid overdoses occurred in both the 6-months prior to and after oral compared to the 6-months post-implant treatment. CONCLUSIONS: The findings support the clinical efficacy of this sustained release naltrexone implant in preventing opioid overdose. However, given the high prevalence of poly-substance use among dependent heroin users, programs offering this type of treatment should also focus on preventing, detecting and managing poly-substance use.