"Everybody is impacted. Everybody's hurting": Grief, loss and the emotional impacts of overdose on harm reduction workers.

BACKGROUND: The emotional impacts of witnessing and responding to overdose and overdose-related deaths have been largely overlooked during the drug toxicity overdose crisis in North America. Scarce research has analyzed these impacts on the health and well-being of harm reduction workers, and the broader determinants of harm reduction work. Our study investigates the experiences and impacts of witnessing and responding to frequent and escalating rates of overdose on harm reduction workers in Toronto, Canada. METHODS: Using semi-structured interviews, 11 harm reduction workers recruited from harm reduction programs with supervised consumption services in Toronto, Canada, explored experiences with and reactions to overdose in both their professional and personal lives. They also provided insights on supports necessary to help people cope with overdose-related loss. We used thematic analysis to develop an initial coding framework, subsequent iterations of codes and emergent themes. RESULTS: Results revealed that harm reductions workers experienced physical, emotional, and social effects from overdose-related loss and grief. While some effects were due to the toll of overdose response and grief from overdose-related losses, they were exacerbated by the lack of political response to the scale of the drug toxicity overdose crisis and the broader socio-economic-political environment of chronic underfunding for harm reduction services. Harm reduction workers described the lack of appropriate workplace supports for trauma from repeated overdose response and overdose-related loss, alongside non-standard work arrangements that resulted in a lack of adequate compensation or access to benefits. CONCLUSIONS: Our study highlights opportunities for organizational practices that better support harm reduction workers, including formal emotional supports and community-based supportive care services. Improvement to the socio-economic-political determinants of work such as adequate compensation and access to full benefit packages are also needed in the harm reduction sector for all workers.

Trends in opioid toxicities among people with and without opioid use disorder and the impact of the COVID-19 pandemic in Ontario, Canada: A population-based analysis.

BACKGROUND: Across Canada, the COVID-19 pandemic occurred amidst an ongoing drug toxicity crisis. Although elevated rates of substance-related harms have been observed nationally, it remains unknown if the pandemic state of emergency led to disproportionate increases in opioid toxicities among people with opioid use disorder (OUD) compared to those without. METHODS: We conducted a population-based repeated cross-sectional time series analysis of fatal and non-fatal opioid toxicities between January 1, 2014, and December 31, 2021, in Ontario, Canada. We used interventional autoregressive integrated moving average models to examine the impact of the pandemic on monthly rates of opioid toxicities per 100,000 Ontario residents stratified by people with and without OUD. RESULTS: We identified 80,296 opioid toxicities of which 53.5 % occurred among people with OUD. Among 52,052 unique individuals, 60.5 % were male and 46.2 % were 25-44 years old. Between January 2014 and December 2021, the rate of opioid toxicities increased from 2.6 to 10.5 per 100,000 (rate ratio [RR]=4.07). The magnitude of this increase differed among people with OUD (0.8 to 7.4 per 100,000; RR=9.35) and without OUD (1.8 to 3.1 per 100,000; RR=1.74). We observed a significant ramp increase in the overall rate of opioid toxicities following the declaration of the pandemic emergency in March 2020 (+0.19 per 100,000 monthly, 95 % CI: 0.029, 0.36, p = 0.021). In a stratified analysis, we found a similar ramp increase among people with OUD (+0.19 per 100,000 monthly, 95 % CI: 0.10, 0.28, p < 0.001); however, this was not observed among people without OUD (p = 0.95). CONCLUSIONS: The rate of opioid toxicities accelerated across Ontario following the pandemic-related state of emergency, with the majority of this increase among people with OUD. The important differences observed among people with OUD compared with those without, highlights the critical need for improved access to harm reduction and treatment interventions among this population.

Validation of case-ascertainment algorithms using health administrative data to identify people who inject drugs in Ontario, Canada.

OBJECTIVES: Health administrative data can be used to improve the health of people who inject drugs by informing public health surveillance and program planning, monitoring, and evaluation. However, methodological gaps in the use of these data persist due to challenges in accurately identifying injection drug use (IDU) at the population level. In this study, we validated case-ascertainment algorithms for identifying people who inject drugs using health administrative data in Ontario, Canada. STUDY DESIGN AND SETTING: Data from cohorts of people with recent (past 12 months) IDU, including those participating in community-based research studies or seeking drug treatment, were linked to health administrative data in Ontario from 1992 to 2020. We assessed the validity of algorithms to identify IDU over varying look-back periods (ie, all years of data [1992 onwards] or within the past 1-5 years), including inpatient and outpatient physician billing claims for drug use, emergency department (ED) visits or hospitalizations for drug use or injection-related infections, and opioid agonist treatment (OAT). RESULTS: Algorithms were validated using data from 15,241 people with recent IDU (918 in community cohorts and 14,323 seeking drug treatment). An algorithm consisting of ≥1 physician visit, ED visit, or hospitalization for drug use, or OAT record could effectively identify IDU history (91.6% sensitivity and 94.2% specificity) and recent IDU (using 3-year look back: 80.4% sensitivity, 99% specificity) among community cohorts. Algorithms were generally more sensitive among people who inject drugs seeking drug treatment. CONCLUSION: Validated algorithms using health administrative data performed well in identifying people who inject drugs. Despite their high sensitivity and specificity, the positive predictive value of these algorithms will vary depending on the underlying prevalence of IDU in the population in which they are applied.

Economic Evaluations of Establishing Opioid Overdose Prevention Centers in 12 North American Cities: A Systematic Review.

OBJECTIVES: Overdose prevention centers (OPCs) provide a safe place where people can consume preobtained drugs under supervision so that a life-saving medical response can be provided quickly in the event of an overdose. OPCs are programs that are established in Canada and have recently become legally sanctioned in only a few United States jurisdictions. METHODS: We conducted a systematic review that summarizes and identifies gaps of economic evidence on establishing OPCs in North America to guide future expansion of OPCs. RESULTS: We included 16 final studies that were evaluated with the Consolidated Health Economic Evaluation Reporting Standards and Drummond checklists. Eight studies reported cost-effectiveness results (eg, cost per overdose avoided or cost per quality-adjusted life-year), with 6 also including cost-benefit; 5 reported only cost-benefit results, and 3 cost offsets. Health outcomes primarily included overdose mortality outcomes or HIV/hepatitis C virus infections averted. Most studies used mathematical modeling and projected OPC outcomes using the experience of a single facility in Vancouver, BC. CONCLUSIONS: OPCs were found to be cost-saving or to have favorable cost-effectiveness or cost-benefit ratios across all studies. Future studies should incorporate the experience of OPCs established in various settings and use a greater diversity of modeling designs.

Episodic disability questionnaire (EDQ) measurement properties among adults living with HIV in Canada, Ireland, United Kingdom, and United States.

BACKGROUND: The Episodic Disability Questionnaire (EDQ) is a generic 35-item patient-reported outcome measure of presence, severity and episodic nature of disability. We assessed the measurement properties of the Episodic Disability Questionnaire (EDQ) with adults living with HIV. METHODS: We conducted a measurement study with adults living with HIV in eight clinical settings in Canada, Ireland, United Kingdom, and United States. We electronically administered the EDQ followed by three reference measures (World Health Organization Disability Assessment Schedule; Patient Health Questionnaire; Social Support Scale) and a demographic questionnaire. We administered the EDQ only 1 week later. We assessed the internal consistency reliability (Cronbach's alpha; > 0.7 acceptable), and test-retest reliability (Intra Class Correlation Coefficient; > 0.7 acceptable). We estimated required change in EDQ domain scores to be 95% certain that a change was not due to measurement error (Minimum Detectable Change (MDC95%)). We evaluated construct validity by assessing 36 primary hypotheses of relationships between EDQ scores and scores on the reference measures (> 75% hypotheses confirmed indicated validity). RESULTS: Three hundred fifty nine participants completed the questionnaires at time point 1, of which 321 (89%) completed the EDQ approximately 1 week later. Cronbach's alpha for internal consistency ranged from 0.84 (social domain) to 0.91 (day domain) for the EDQ severity scale, and 0.72 (uncertainty domain) to 0.88 (day domain) for the EDQ presence scale, and 0.87 (physical, cognitive, mental-emotional domains) to 0.89 (uncertainty domain) for the EDQ episodic scale. ICCs for test-retest reliability ranged from 0.79 (physical domain) to 0.88 (day domain) for the EDQ severity scale and from 0.71 (uncertainty domain) to 0.85 (day domain) for the EDQ presence scale. Highest precision was demonstrated in the severity scale for each domain (MDC95% range: 19-25 out of 100), followed by the presence (MDC95% range: 37-54) and episodic scales (MDC95% range:44-76). Twenty-nine of 36 (81%) construct validity hypotheses were confirmed. CONCLUSIONS: The EDQ possesses internal consistency reliability, construct validity, and test-retest reliability, with limited precision when administered electronically with adults living with HIV across in clinical settings in four countries. Given the measurement properties, the EDQ can be used for group level comparisons for research and program evaluation in adults living with HIV.

The multiple makings of a supervised consumption service in a hospital setting.

BACKGROUND: Whereas supervised consumption services (SCSs) are common in many community settings, they are seldomly found in acute care hospitals. As hospitals present unique circumstances that can shape the impacts of an SCS, careful consideration of local implementation contexts and practices is required. We explored the pre-implementation stage of an SCS, to examine how an SCS is made and made differently in relation to the material-discursive context of the hospital. METHODS: We conducted 11 focus groups with 83 staff and clinicians at an inner-city hospital in Toronto, Canada. Data analysis followed principles of grounded theory and was informed by an 'evidence making interventions' framework. RESULTS: While most participants indicated they would support the establishment of an SCS at the hospital, multiple enactments of an SCS emerged. An SCS was enacted: as a means to reduce drug-related risks for all people who use drugs, as an opportunity to intervene on patients' drug use, as a means to centralize drug use, and as a transformative intervention for the hospital. In our findings, harm reduction, abstinence, security, and risk mitigation goals existed closely together, yielding overlaying realities. CONCLUSION: Our findings revealed various enactments of an SCS, some of which are likely to negatively affect people who use drugs and service access. As more hospitals consider the implementation of an SCS, understanding how an SCS is made in practice will be key to building a service that focuses on the needs of people who use drugs.

Initiation of opioid agonist therapy after hospital visits for opioid poisonings in Ontario.

BACKGROUND: Emergency department visits and hospital admissions for opioid toxicity are opportunities to initiate opioid agonist therapy (OAT), which reduces morbidity and mortality in patients with opioid use disorder (OUD). The study objectives were to evaluate OAT initiation rates after a hospital encounter for opioid toxicity in Ontario, Canada, and determine whether publication of a 2018 Canadian OUD management guideline was associated with increased initiation. METHODS: We conducted a retrospective, population-based serial cross-sectional study of hospital encounters for opioid toxicity among patients with OUD between Jan. 1, 2013, and Mar. 31, 2020, in Ontario, Canada. The primary outcome was OAT initiation (methadone, buprenorphine-naloxone, or slow-release oral morphine) within 7 days of discharge, measured quarterly. We examined the impact of the release of the OUD management guideline on OAT initiation rates using Autoregressive Integrated Moving Average models. RESULTS: Among 20 702 hospital visits for opioid toxicity among patients with OUD, the median age was 35 years, and 65.1% were male. Over the study period, the percentage of visits leading to OAT initiation within 7 days rose from 1.7% or less (Q1 2013) to 5.6% (Q1 2020); however, the publication of the Canadian OUD management guideline was not associated with a significant increase in these rates (0.14% slope change, 95% confidence interval -0.11% to 0.38%; p = 0.3). INTERPRETATION: Among hospital encounters for opioid toxicity, despite rising prevalence over time, only 1 in 18 patients were dispensed OAT within a week of discharge in early 2020. These findings highlight missed opportunities to initiate therapies proven to reduce mortality in patients with OUD.

Initiations of safer supply hydromorphone increased during the COVID-19 pandemic in Ontario: An interrupted time series analysis.

AIMS: Calls to prescribe safer supply hydromorphone (SSHM) as an alternative to the toxic drug supply increased during the COVID-19 pandemic but it is unknown whether prescribing behaviour was altered. We aimed to evaluate how the number of new SSHM dispensations changed during the pandemic in Ontario. METHODS: We conducted a retrospective interrupted time-series analysis using provincial administrative databases. We counted new SSHM dispensations in successive 28-day periods from March 22, 2016 to August 30, 2021. We used segmented Poisson regression methods to test for both a change in level and trend of new dispensations before and after March 17, 2020, the date Ontario's pandemic-related emergency was declared. We adjusted the models to account for seasonality and assessed for over-dispersion and residual autocorrelation. We used counterfactual analysis methods to estimate the number of new dispensations attributable to the pandemic. RESULTS: We identified 1489 new SSHM dispensations during the study period (434 [mean of 8 per 28-day period] before and 1055 [mean of 56 per 28-day period] during the pandemic). Median age of individuals initiating SSHM was 40 (interquartile interval 33-48) with 61.7% (N = 919) male sex. Before the pandemic, there was a small trend of increased prescribing (incidence rate ratio [IRR] per period 1.002; 95% confidence interval [95CI] 1.001-1.002; p<0.001), with a change in level (immediate increase) at the pandemic date (relative increase in IRR 1.674; 95CI 1.206-2.322; p = 0.002). The trend during the pandemic was not statistically significant (relative increase in IRR 1.000; 95CI 1.000-1.001; p = 0.251). We estimated 511 (95CI 327-695) new dispensations would not have occurred without the pandemic. CONCLUSION: The pandemic led to an abrupt increase in SSHM prescribing in Ontario, although the rate of increase was similar before and during the pandemic. The absolute number of individuals who accessed SSHM remained low throughout the pandemic.

Client experiences using a new supervised consumption service in Sudbury, Ontario: A qualitative study.

Overdoses are increasing in the province of Ontario, Canada, where northern communities such as Sudbury have witnessed disproportionately elevated rates, with opioid-related deaths double that of the provincial average. To address this issue, governments have implemented supervised consumption services (SCS) where people who use drugs (PWUD) can use their pre-obtained substances onsite under trained supervision. In September 2022, the city of Sudbury opened its first SCS, 'The Spot', but the site's sustainability is contingent on demonstrating benefit to PWUD and the neighboring community. We undertook a qualitative study exploring experiences among clients who used the consumption service inside The Spot. In December 2022, clients of The Spot were invited to participate in a brief survey which collected socio-demographic information and substance use profiles, followed by an in-person semi-structured qualitative interview. Participant survey and interview data were combined with administrative site utilization data provided by site staff of all clients who accessed the consumption service from September 2022 to August 2023 to examine overall service utilization and uptake. Qualitative data were analyzed using iterative thematic analysis techniques, and results were informed by common responses to research questions. The responses were narratively presented. Administrative site utilization data highlighted a relatively stable increase in uptake and utilization of the site since its inception. A total of 20 clients participated in the survey and semi-structured interviews. Participants described the importance of the site in preventing and responding to overdoses, providing a safe and comfortable environment to consume their drugs, and decreasing public drug use, which they suggested may potentially reduce stigmatization in the community. However, clients also suggested challenges, including issues regarding site operational policies that hindered consumption room utilization. Service suggestions made by clients to improve site utilization include the addition of inhalation services, relocating the site to a location in downtown Sudbury where PWUD commonly congregate, and extending operational hours. Positive impacts and recommendations can be drawn on and considered by other northern or rural communities interested in implementing similar harm reduction services.

'I don't chase drugs as much anymore, and I'm not dead': Client reported outcomes associated with safer opioid supply programs in Ontario, Canada.

INTRODUCTION: The ongoing opioid overdose crisis, which has killed over 30,000 people in Canada since 2016, is driven by the volatility of an unregulated opioid drug supply comprised primarily of fentanyl. The Canadian government has recently funded safer opioid supply (SOS) programs, which include off-label prescriptions of pharmaceutical-grade opioids to high risk individuals with the goal of reducing overdose deaths. METHODS: In 2021, we examined the implementation and adaption of four SOS programs in Ontario. These programs use a primary care model and serve communities experiencing marginalisation. We conducted semi-structured interviews with program clients. We present the results of a thematic analysis with the aim of describing clients' self-reported impact of these programs on their health and well-being. RESULTS: We interviewed 52 clients between June and October 2021 (mean age 47 years, 56% men, 17% self-identified Indigenous, 14% living with HIV). Our results indicate multifaceted pathways to improved self-reported health and well-being among clients including changes to drug use practices, fewer overdoses, reduced criminalised activity, improved trust and engagement in health care, and increased social stability (e.g., housing). DISCUSSION AND CONCLUSION: Most clients reported that the intervention saved their life because of the reduced frequency of overdoses. Findings suggest that SOS programs improved clients' health outcomes and increase opportunities for engagement in health services. Our results provide insight into the mechanisms behind some of the emergent evidence on the impact of safer supply prescribing.

Constrained Optimization for Decision Making in Health Care Using Python: A Tutorial.

HIGHLIGHTS: This tutorial provides a user-friendly guide to mathematically formulating constrained optimization problems and implementing them using Python.Two examples are presented to illustrate how constrained optimization is used in health applications, with accompanying Python code provided.

Burden of opioid toxicity death in the fentanyl-dominant era for people who experience incarceration in Ontario, Canada, 2015-2020: a whole population retrospective cohort study.

OBJECTIVES: To describe mortality due to opioid toxicity among people who experienced incarceration in Ontario between 2015 and 2020, during the fentanyl-dominant era. DESIGN: In this retrospective cohort study, we linked Ontario coronial data on opioid toxicity deaths between 2015 and 2020 with correctional data for adults incarcerated in Ontario provincial correctional facilities. SETTING: Ontario, Canada. PARTICIPANTS: Whole population data. MAIN OUTCOMES AND MEASURES: The primary outcome was opioid toxicity death and the exposure was any incarceration in a provincial correctional facility between 2015 and 2020. We calculated crude death rates and age-standardised mortality ratios (SMR). RESULTS: Between 2015 and 2020, 8460 people died from opioid toxicity in Ontario. Of those, 2207 (26.1%) were exposed to incarceration during the study period. Among those exposed to incarceration during the study period (n=1 29 152), 1.7% died from opioid toxicity during this period. Crude opioid toxicity death rates per 10 000 persons years were 43.6 (95% CI=41.8 to 45.5) for those exposed to incarceration and 0.95 (95% CI=0.93 to 0.97) for those not exposed. Compared with those not exposed, the SMR for people exposed to incarceration was 31.2 (95% CI=29.8 to 32.6), and differed by sex, at 28.1 (95% CI=26.7 to 29.5) for males and 77.7 (95% CI=69.6 to 85.9) for females. For those exposed to incarceration who died from opioid toxicity, 10.6% died within 14 days of release and the risk was highest between days 4 and 7 postrelease, at 288.1 per 10 000 person years (95% CI=227.8 to 348.1). CONCLUSIONS: The risk of opioid toxicity death is many times higher for people who experience incarceration compared with others in Ontario. Risk is markedly elevated in the week after release, and women who experience incarceration have a substantially higher SMR than men who experience incarceration. Initiatives to prevent deaths should consider programmes and policies in correctional facilities to address high risk on release.

Episodic Disability Questionnaire (EDQ) measurement properties among adults living with HIV in Canada, Ireland, United Kingdom, and United States.

Background: The Episodic Disability Questionnaire (EDQ) is a generic 35-item patient-reported outcome measure of presence, severity and episodic nature of disability. We assessed the measurement properties of the Episodic Disability Questionnaire (EDQ) with adults living with HIV. Methods: We conducted a measurement study with adults living with HIV in eight clinical settings in Canada, Ireland, United Kingdom, and United States. We electronically administered the EDQ followed by three reference measures (World Health Organization Disability Assessment Schedule; Patient Health Questionnaire; Social Support Scale) and a demographic questionnaire. We administered the EDQ only 1 week later. We assessed the internal consistency reliability (Cronbach's alpha; >0.7 acceptable), and test-retest reliability (Intra Class Correlation Coefficient; >0.7 acceptable). We estimated required change in EDQ domain scores to be 95% certain that a change was not due to measurement error (Minimum Detectable Change (MDC95%)). We evaluated construct validity by assessing 36 primary hypotheses of relationships between EDQ scores and scores on the reference measures (> 75% hypotheses confirmed indicated validity). Results: 359 participants completed the questionnaires at time point 1, of which 321 (89%) completed the EDQ approximately 1 week later. Cronbach's alpha for internal consistency ranged from 0.84 (social domain) to 0.91 (day domain) for the EDQ severity scale, and 0.72 (uncertainty domain) to 0.88 (day domain) for the EDQ presence scale, and 0.87 (physical, cognitive, mental-emotional domains) to 0.89 (uncertainty domain) for the EDQ episodic scale. ICCs for test-retest reliability ranged from 0.79 (physical domain) to 0.88 (day domain) for the EDQ severity scale and from 0.71 (uncertainty domain) to 0.85 (day domain) for the EDQ presence scale. Highest precision was demonstrated in the severity scale for each domain (MDC95% range: 19-25 out of 100), followed by the presence (MDC95% range: 37-54) and episodic scales (MDC95% range:44-76). Twenty-nine of 36 (81%) construct validity hypotheses were confirmed. Conclusions: The EDQ possesses internal consistency reliability, construct validity, and test-retest reliability, with limited precision when administered electronically with adults living with HIV across in clinical settings in four countries. Given the measurement properties, the EDQ can be used for group level comparisons for research and program evaluation in adults living with HIV.

Controlled-release hydromorphone and risk of infection in adults: a systematic review.

BACKGROUND: Preliminary evidence suggests that people who inject drugs (PWID) may be at an increased risk of developing infective endocarditis (IE), hepatitis C virus (HCV) infection, and/or human immunodeficiency virus (HIV) infection from hydromorphone controlled-release formulation. The hypothesized mechanism is related to insolubility of the drug, which promotes reuse, leading to contamination of injecting equipment. However, this relationship has not been confirmed. We aimed to conduct a systematic review including adult PWID exposed to controlled-release hydromorphone and the risk of acquiring IE, HCV, and HIV. METHODS: We searched MEDLINE, EMBASE, and Evidence Based Medicine reviews from inception until September 2021. Following pilot testing, two reviewers conducted all screening of citations and full-text articles, as well as abstracted data, and appraised risk of bias using the Newcastle-Ottawa scale and Effective Practice and Organization of Care tool. Equity issues were examined using the PROGRESS-PLUS framework. Discrepancies were resolved consistently by a third reviewer. Meta-analysis was not feasible due to heterogeneity across the studies. RESULTS: After screening 3,231 citations from electronic databases, 722 citations from unpublished sources/reference scanning, and 626 full-text articles, five studies were included. Five were cohort studies, and one was a case-control study. The risk of bias varied across the studies. Two studies reported on gender, as well as other PROGRESS-PLUS criteria (race, housing, and employment). Three studies focused specifically on the controlled-release formulation of hydromorphone, whereas two studies focused on all formulations of hydromorphone. One retrospective cohort study found an association between controlled-release hydromorphone and IE, whereas a case-control study found no evidence of an association. One retrospective cohort study found an association between the number of hydromorphone controlled-release prescriptions and prevalence of HCV. None of the studies specifically reported on associations with HIV. DISCUSSION: Very few studies have examined the risk of IE, HCV, and HIV infection after exposure to controlled-release hydromorphone. Very low-quality and scant evidence suggests uncertainty around the risks of blood-borne infections, such as HCV and IE to PWID using this medication.

Piloting an online telecoaching community-based exercise intervention with adults living with HIV: protocol for a mixed-methods implementation science study.

INTRODUCTION: Our aim is to evaluate the implementation of an online telecoaching community-based exercise (CBE) intervention with the goal of reducing disability and enhancing physical activity and health among adults living with HIV. METHODS AND ANALYSIS: We will conduct a prospective longitudinal mixed-methods two-phased intervention study to pilot the implementation of an online CBE intervention with ~30 adults (≥18 years) living with HIV who consider themselves safe to participate in exercise. In the intervention phase (0-6 months), participants will take part in an online CBE intervention involving thrice weekly exercise (aerobic, resistance, balance and flexibility), with supervised biweekly personal training sessions with a fitness instructor, YMCA membership providing access to online exercise classes, wireless physical activity monitor to track physical activity and monthly online educational sessions on topics related to HIV, physical activity and health. In the follow-up phase (6-12 months), participants will be encouraged to continue independent exercise thrice weekly. Quantitative assessment: Bimonthly, we will assess cardiopulmonary fitness, strength, weight, body composition and flexibility, followed by administering self-reported questionnaires to assess disability, contextual factor outcomes (mastery, engagement in care, stigma, social support), implementation factors (cost, feasibility, technology), health status and self-reported physical activity. We will conduct a segmented regression analyses to describe the change in level and trend between the intervention and follow-up phases. Qualitative assessment: We will conduct online interviews with a subsample of ~10 participants and 5 CBE stakeholders at baseline (month 0), postintervention (month 6) and end of follow-up (month 12) to explore experiences, impact and implementation factors for online CBE. Interviews will be audiorecorded and analysed using content analytical techniques. ETHICS AND DISSEMINATION: Protocol approved by the University of Toronto Research Ethics Board (Protocol # 40410). Knowledge translation will occur in the form of presentations and publications in open-access peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05006391.

How do members of the public expect to use variants of uncertain significance in their health care? A population-based survey.

PURPOSE: Genomic sequencing can generate complex results, including variants of uncertain significance (VUS). In general, VUS should not inform clinical decision-making. This study aimed to assess the public's expected management of VUS. METHODS: An online, hypothetical survey was conducted among members of the Canadian public preceded by an educational video. Participants were randomized to 1 of 2 arms, VUS or pathogenic variant in a colorectal cancer gene, and asked which types of health services they expected to use for this result. Expected health service use was compared between randomization arms, and associations between participants' sociodemographic characteristics, attitudes, and medical history were explored. RESULTS: Among 1003 respondents (completion rate 60%), more participants expected to use each type of health service for a pathogenic variant than for a VUS. However, a considerable proportion of participants expected to request monitoring (73.4%) and consult health care providers (60.9%) for a VUS. There was evidence to support associations between expectation to use health services for a VUS with family history of genetic disease, family history of cancer, education, and attitudes toward health care and technology. CONCLUSION: Many participants expected to use health services for a VUS in a colorectal cancer predisposition gene, suggesting a potential disconnect between patients' expectations for VUS management and guideline-recommended care.

Developing a fall prevention intervention economic model.

PURPOSE: Model-based economic evaluations require conceptualization of the model structure. Our objectives were to identify important health states, events, and patient attributes to be included in a model-based cost-effectiveness analysis of fall prevention interventions, to develop a model structure to examine cost-effectiveness of fall prevention interventions, and to assess the face validity of the model structure. METHODS: An expert panel comprising clinicians, health service researchers, health economists, a patient partner, and policy makers completed two rounds of online surveys to gain consensus on health states, events, and patient attributes important for fall prevention interventions. The surveys were informed by a literature search on fall prevention interventions for older adults (≥65 years) including economic evaluations and clinical practice guidelines. The results of the Delphi surveys and subsequent discussions can support the face validity of a state-transition model for an economic evaluation of fall prevention interventions. RESULTS: In total, 11 experts rated 24 health states/events and 41 patient attributes. Consensus was achieved on 14 health states/events and 26 patient characteristics. The proposed model structure incorporated 12 of the 14 selected health states/events. Panelists confirmed the face validity of the model structure during teleconferences. CONCLUSIONS: There is a dearth of studies presenting the model conceptualization process; consequently, this study involving multiple end user partners with opportunities for input at several stages adds to the literature as another case study. This process is an example of how a fall prevention economic model was developed using a modified Delphi process and assessed for face validity.

Association of Illicit Fentanyl Use with Injection Risk Practices Among People who Inject Drugs.

We investigated the association between fentanyl injection frequency and sharing of injection equipment among people who inject drugs. We surveyed 249 people who inject drugs in Toronto in 2019. We estimated predicted probabilities of associations between fentanyl injection frequency and injection risk practices. In prior 6 months, 117 (47.0%) of participants injected fentanyl daily, 49 (19.7%) less than daily, and 78 (31.3%) did not inject fentanyl. Participants who injected fentanyl daily shared syringes more often than those not injecting fentanyl (25.0% vs. 4.9%; χ2 = 11.54, p = 0.0007). Participants who injected fentanyl daily (42.4% vs. 11.3%; χ2 = 18.05, p < 0.0001) and less than daily (37.2% vs. 11.3%; χ2 = 5.88 p = 0.02) shared cookers more often than those not injecting fentanyl. Participants who injected fentanyl daily (30.2% vs. 9.7%; χ2 = 9.05, p = 0.003) and less than daily (30.3% vs. 9.7%; χ2 = 4.11, p = 0.04) shared filters more often than those not injecting fentanyl. No differences in probabilities of sharing equipment were detected between participants who injected fentanyl daily and less than daily. People using fentanyl reported injection practices that increased risk for infectious disease transmission.

Evaluation of the gap in delivery of opioid agonist therapy among individuals with opioid-related health problems: a population-based retrospective cohort study.

AIMS: Although opioid-related harms have reached new heights across North America, the size of the gap in opioid agonist therapy (OAT) delivery for opioid-related health problems is unknown in most jurisdictions. This study sought to characterize the gap in OAT treatment using a cascade of care framework, and determine factors associated with engagement and retention in treatment. DESIGN: A population-based retrospective cohort study. SETTING: Ontario, Canada. PARTICIPANTS: Individuals who sought medical care for opioid-related health problems or died from an opioid-related cause between 2005 and 2019. MEASUREMENTS: Monthly treatment status for buprenorphine/naloxone or methadone OAT between 2013 and 2019 (i.e. 'off OAT', 'retained on OAT < 6 months', 'retained on OAT ≥ 6 months'). FINDINGS: Of 122 811 individuals in the cohort, 97 516 (79.4%) received OAT at least once during the study period. There was decreasing 6-month treatment retention over time. Model results indicated that males had higher odds of being on OAT each month [odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.23-1.28] but lower odds of OAT retention (OR = 0.90, 95% CI = 0.88-0.92), while the reverse was observed for older individuals (monthly: OR = 0.76 per 10-year increase, 95% CI = 0.76-0.77; retention: OR = 1.36 per 10-year increase, 95% CI = 1.34-1.38) and individuals with higher neighbourhood income (e.g. highest income quintile, monthly: OR = 0.79, 95% CI = 0.77-0.82; highest income quintile, retention: OR = 1.15, 95% CI = 1.11-1.20). Individuals residing in rural areas and with a history of mental health diagnoses had poorer outcomes overall, including lower odds of being on OAT each month (rural: OR = 0.75, 95% CI = 0.73-0.78; mental health: OR = 0.89, 95% CI = 0.87-0.92) and OAT retention (rural: OR = 0.79, 95% CI = 0.77-0.82; mental health: OR = 0.81, 95% CI = 0.78-0.83), as well as higher risk of starting/stopping OAT [rural, starting OAT: hazard ratio (HR) = 1.07, 95% CI = 1.05-1.10; mental health, starting OAT: HR = 1.20, 95% CI: 1.18-1.23; rural, stopping OAT: HR = 1.24, 95% CI: = 1.22-1.26; mental health, stopping OAT: HR = 1.11, 95% CI = 1.09-1.13]. Individuals with a history of mental health diagnoses also had a higher risk of death, regardless of OAT status (off OAT death: HR = 1.49, 95% CI = 1.33-1.66; on OAT death: HR = 1.20, 95% CI = 1.09-1.31). CONCLUSIONS: Factors influencing engagement and declining retention in treatment with opioid agonist therapy in Ontario's health system include age, sex and neighbourhood income, as well as mental health diagnoses or residing in rural regions.