Ongoing Gaps in the Hepatitis C Care Cascade during the Direct-Acting Antiviral Era in a Large Retrospective Cohort in Canada: A Population-Based Study.

To achieve hepatitis C virus (HCV) elimination, high uptake along the care cascade steps for all will be necessary. We mapped engagement with the care cascade overall and among priority groups in the post-direct-acting antivirals (DAAs) period and assessed if this changed relative to pre-DAAs. We created a population-based cohort of all reported HCV diagnoses in Quebec (1990-2018) and constructed the care cascade [antibody diagnosed, RNA tested, RNA positive, genotyped, treated, sustained virologic response (SVR)] in 2013 and 2018. Characteristics associated with RNA testing and treatment initiation were investigated using marginal logistic models via generalized estimating equations. Of the 31,439 individuals HCV-diagnosed in Quebec since 1990 and alive as of 2018, there was significant progress in engagement with the care cascade post- vs. pre-DAAs; 86% vs. 77% were RNA-tested, and 64% vs. 40% initiated treatment. As of 2018, a higher risk of not being RNA-tested or treated was observed among individuals born <1945 vs. >1965 [hazard ratio (HR); 95% CI; 1.35 (1.16-1.57)], those with material and social deprivation [1.21 (1.06-1.38)], and those with alcohol use disorder [1.21 (1.08-1.360]. Overall, non-immigrants had lower rates of RNA testing [0.76 (0.67-0.85)] and treatment initiation [0.63 (0.57-0.70)] than immigrants. As of 2018, PWID had a lower risk of not being RNA tested [0.67 (0.61-0.85)] but a similar risk of not being treated, compared to non-PWID. Engagement in the HCV care cascade have improved in the post-DAA era, but inequities remain. Vulnerable subgroups, including certain older immigrants, were less likely to have received RNA testing or treatment as of 2018 and would benefit from focused interventions to strengthen these steps.

Temporal Trends and Determinants of HIV Testing at Antenatal Care in Sub-Saharan Africa: A Pooled Analysis of Population-Based Surveys (2005-2021).

BACKGROUND: In sub-Saharan Africa (SSA), integrating HIV testing into antenatal care (ANC) has been crucial toward reducing mother-to-child transmission of HIV. With the introduction of new testing modalities, we explored temporal trends in HIV testing within and outside of ANC and identified sociodemographic determinants of testing during ANC. METHODS: We analyzed data from 139 nationally representative household surveys conducted between 2005 and 2021, including more than 2.2 million women aged 15-49 years in 41 SSA countries. We extracted data on women's recent HIV testing history (<24 months), by modality (ie, at ANC versus outside of ANC) and sociodemographic variables (ie, age, socioeconomic status, education level, number of births, urban/rural). We used Bayesian generalized linear mixed models to estimate HIV testing coverage and the proportion of those that tested as part of ANC. RESULTS: HIV testing coverage (<24 months) increased substantially between 2005 and 2021 from 8% to 38%, with significant variations between countries and subregions. Two percent of women received an HIV test in the 24 months preceding the survey interview as part of ANC in 2005 and 11% in 2021. Among women who received an HIV test in the 24 months preceding the survey, the probability of testing at ANC was significantly greater for multiparous, adolescent girls, rural women, women in the poorest wealth quintile, and women in West and Central Africa. CONCLUSION: ANC testing remains an important component to achieving high levels of HIV testing coverage and benefits otherwise underserved women, which could prove instrumental to progress toward universal knowledge of HIV status in SSA.

Characteristics of male perpetrators of intimate partner violence and implications for women's HIV status: A pooled analysis of cohabiting couples from 27 countries in Africa (2000-2020).

Intimate partner violence (IPV) may increase women's HIV acquisition risk. Still, knowledge on pathways through which IPV exacerbates HIV burden is emerging. We examined the individual and partnership-level characteristics of male perpetrators of physical and/or sexual IPV and considered their implications for women's HIV status. We pooled individual-level data from nationally representative, cross-sectional surveys in 27 countries in Africa (2000-2020) with information on past-year physical and/or sexual IPV and HIV serology among cohabiting couples (≥15 years). Current partners of women experiencing past-year IPV were assumed to be IPV perpetrators. We used Poisson regression, based on Generalized Estimating Equations, to estimate prevalence ratios (PR) for male partner and partnership-level factors associated with perpetration of IPV, and men's HIV status. We used marginal standardization to estimate the adjusted risk differences (aRD) quantifying the incremental effect of IPV on women's risk of living with HIV, beyond the risk from their partners' HIV status. Models were adjusted for survey fixed effects and potential confounders. In the 48 surveys available from 27 countries (N = 111,659 couples), one-fifth of women reported that their partner had perpetrated IPV in the past year. Men who perpetrated IPV were more likely to be living with HIV (aPR = 1.09; 95%CI: 1.01-1.16). The aRD for living with HIV among women aged 15-24 whose partners were HIV seropositive and perpetrated past-year IPV was 30% (95%CI: 26%-35%), compared to women whose partners were HIV seronegative and did not perpetrate IPV. Compared to the same group, aRD among women whose partner was HIV seropositive without perpetrating IPV was 27% (95%CI: 23%-30%). Men who perpetrated IPV are more likely to be living with HIV. IPV is associated with a slight increase in young women's risk of living with HIV beyond the risk of having an HIV seropositive partner, which suggests the mutually reinforcing effects of HIV/IPV.

A population-based study of reported hepatitis C diagnoses from 1998 to 2018 in immigrants and nonimmigrants in Quebec, Canada.

Immigrants living in low hepatitis C (HCV) prevalence countries bear a disproportionate HCV burden, but there are limited HCV population-based studies focussed on this population. We estimated rates and trends of reported HCV diagnoses over a 20-year period in Quebec, Canada, to investigate subgroups with the highest rates and changes over time. A population-based cohort of all reported HCV diagnoses in Quebec (1998-2018) linked to health administrative and immigration databases. HCV rates, rate ratios (RR) and trends overall and stratified by immigrant status and country of birth were estimated using Poisson regression. Among 38,348 HCV diagnoses, 14% occurred in immigrants, a median of 7.5 years after arrival. The average annual HCV rate/100,000 decreased for immigrants and nonimmigrants, but the risk (RR) among immigrants increased over the study period [35.7 vs. 34.5 (RR = 1.03) and 18.4 vs. 12.7 (1.45) between 1998-2008 and 2009-2018]. Immigrants from middle-income Europe & Central Asia [55.8 (RR = 4.39)], sub-Saharan Africa [51.7 (RR = 4.06)] and South Asia [32.8 (RR = 2.58)] had the highest rates between 2009 and 2018. Annual HCV rates decreased more slowly among immigrants vs. nonimmigrants (-5.9% vs. -8.9%, p < 0.001), resulting in a 2.5-fold (9%-21%) increase in the proportion of HCV diagnoses among immigrants (1998-2018). The slower decline in HCV rates among immigrants over the study period highlights the need for targeted screening for this population, particularly those from sub-Saharan Africa, Asia and middle-income Europe. These data can inform micro-elimination efforts in Canada and other low-HCV-prevalence countries.

The effects of intimate partner violence on women's risk of HIV acquisition and engagement in the HIV treatment and care cascade: a pooled analysis of nationally representative surveys in sub-Saharan Africa.

BACKGROUND: Achieving the 95-95-95 targets for HIV diagnosis, treatment, and viral load suppression to end the HIV epidemic hinges on eliminating structural inequalities, including intimate partner violence (IPV). Sub-Saharan Africa has among the highest prevalence of IPV and HIV worldwide. We aimed to examine the effects of IPV on recent HIV infection and women's engagement in the HIV care cascade in sub-Saharan Africa. METHODS: We did a retrospective pooled analysis of data from nationally representative, cross-sectional surveys with information on physical or sexual IPV (or both) and HIV testing, from Jan 1, 2000, to Dec 31, 2020. Relevant surveys were identified from data catalogues and previous large-scale reviews, and included the Demographic and Health Survey, the AIDS Indicator Survey, the Population-based HIV Impact Assessment, and the South Africa National HIV Prevalence, Incidence, Behavior and Communication Survey. Individual-level data on all female respondents who were ever-partnered (currently or formerly married or cohabiting) and aged 15 years or older were included. We used Poisson regression to estimate crude and adjusted prevalence ratios (PRs) for the association between past-year experience of physical or sexual IPV (or both), as the primary exposure, and recent HIV infection (measured with recency assays), as the primary outcome. We also assessed associations of past-year IPV with self-reported HIV testing (also in the past year), and antiretroviral therapy (ART) uptake and viral load suppression at the time of surveying. Models were adjusted for participant age, age at sexual debut (HIV recency analysis), urban or rural residency, partnership status, education, and survey-level fixed effects. FINDINGS: 57 surveys with data on self-reported HIV testing and past-year physical or sexual IPV were available from 30 countries, encompassing 280 259 ever-partnered women aged 15-64 years. 59 456 (21·2%) women had experienced physical or sexual IPV in the past year. Six surveys had information on recent HIV infection and seven had data on ART uptake and viral load suppression. The crude PR for recent HIV infection among women who had experienced past-year physical or sexual IPV, versus those who had not, was 3·51 (95% CI 1·64-7·51; n=19 179). The adjusted PR was 3·22 (1·51-6·85). Past-year physical or sexual IPV had minimal effect on self-reported HIV testing in the past year in crude analysis (PR 0·97 [0·96-0·98]; n=274 506) and adjusted analysis (adjusted PR 0·99 [0·98-1·01]). Results were inconclusive for the association of ART uptake with past-year IPV among women living with HIV (crude PR 0·90 [0·85-0·96], adjusted PR 0·96 [0·90-1·02]; n=5629). Women living with HIV who had experienced physical or sexual IPV in the past year were less likely to achieve viral load suppression than those who had not experienced past-year IPV (crude PR 0·85 [0·79-0·91], adjusted PR 0·91 [0·84-0·98], n=5627). INTERPRETATION: Past-year physical or sexual IPV was associated with recent HIV acquisition and less frequent viral load suppression. Preventing IPV is inherently imperative but eliminating IPV could contribute to ending the HIV epidemic. FUNDING: Canadian Institutes of Health Research, the Canada Research Chairs Program, and Fonds de recherche du Québec-Santé. TRANSLATIONS: For the French, Spanish and Portuguese translations of the abstract see Supplementary Materials section.

Developing International Classification of Disease code definitions for the study of enteric infection sequelae in Canada.

Background: Enteric infections and their chronic sequelae are a major cause of disability and death. Despite the increasing use of administrative health data in measuring the burden of chronic diseases in the population, there is a lack of validated International Classification of Disease (ICD) code-based case definitions, particularly in the Canadian context. Our objective was to validate ICD code definitions for sequelae of enteric infections in Canada: acute kidney injury (AKI); hemolytic uremic syndrome (HUS); thrombotic thrombocytopenic purpura (TTP); Guillain-Barré syndrome/Miller-Fisher syndrome (GBS/MFS); chronic inflammatory demyelinating polyneuropathy (CIDP); ankylosing spondylitis (AS); reactive arthritis; anterior uveitis; Crohn's disease, ulcerative colitis, celiac disease, erythema nodosum (EN); neonatal listeriosis (NL); and Graves' disease (GD). Methods: We used a multi-step approach by conducting a literature review to identify existing validated definitions, a clinician assessment of the validated definitions, a chart review to verify proposed definitions and a final clinician review. We measured the sensitivity and positive predictive value (PPV) of proposed definitions. Results: Forty studies met inclusion criteria. We identified validated definitions for 12 sequelae; clinicians developed three (EN, NL, GD). We reviewed 181 charts for 6 sequelae (AKI, HUS, TTP, GBS/MFS, CIDP, AS). Sensitivity (42.8%-100%) and PPV (63.6%-100%) of ICD code definitions varied. Six definitions were modified by clinicians following the chart review (AKI, TTP, GBS/MFS, CIDP, AS, reactive arthritis) to reflect coding practices, increase specificity or sensitivity, and address logistical constraints. Conclusion: The multi-step design to derive ICD code definitions provided flexibility to identify existing definitions, to improve their sensitivity and PPV and adapt them to the Canadian context.

Patterns of enteric infections in a population-wide cohort study of sequelae, British Columbia, Canada.

We assessed patterns of enteric infections caused by 14 pathogens, in a longitudinal cohort study of sequelae in British Columbia (BC) Canada, 2005-2014. Our population cohort of 5.8 million individuals was followed for an average of 7.5 years/person; during this time, 40 523 individuals experienced 42 308 incident laboratory-confirmed, provincially reported enteric infections (96.4 incident infections per 100 000 person-years). Most individuals (38 882/40 523; 96%) had only one, but 4% had multiple concurrent infections or more than one infection across the study. Among individuals with more than one infection, the pathogens and combinations occurring most frequently per individual matched the pathogens occurring most frequently in the BC population. An additional 298 557 new fee-for-service physician visits and hospitalisations for enteric infections, that did not coincide with a reported enteric infection, also occurred, and some may be potentially unreported enteric infections. Our findings demonstrate that sequelae risk analyses should explore the possible impacts of multiple infections, and that estimating risk for individuals who may have had a potentially unreported enteric infection is warranted.

Using synthetic controls to estimate the population-level effects of Ontario's recently implemented overdose prevention sites and consumption and treatment services.

BACKGROUND: Between 2017 and 2020, Ontario implemented overdose prevention sites (OPS) and consumption and treatment services (CTS) in nine of its 34 public health units (PHU). We tested for the effect of booth-hours (spaces within OPS/CTSs for supervised consumption) on opioid-related health service use and mortality rates at the provincial- (aggregate) and PHU-level. METHODS: We used monthly rates of all opioid-related emergency department (ED) visits, hospitalizations, and deaths between January 2015 and March 2021 as our three outcomes. For each PHU that implemented OPS/CTSs, we created a synthetic control as a weighted combination of unexposed PHUs. Our exposure was the time-varying rate of booth-hours provided. We estimated the population-level effects of the intervention on each outcome per treated/synthetic-control pair using controlled interrupted time series with segmented regression; and tested for the aggregate effect using a multiple baseline approach. We adjusted for time-varying provision of prescription opioids for pain management, opioid agonist treatment (OAT), and naloxone kits; and corrected for seasonality and autocorrelation. All rates were per 100,000 population. For sensitivity analysis, we restricted the post-implementation period to before COVID-19 public health measures were implemented (March 2020). RESULTS: Our aggregate analyses found no effect per booth-hour on ED visits (0.00, 95% CI: -0.01, 0.01; p-value=0.6684), hospitalizations (0.00, 95% CI: 0.00, 0.00; p-value=0.9710) or deaths (0.00, 95% CI: 0.00, 0.00; p-value=0.2466). However, OAT reduced ED visits (-0.20, 95% CI: -0.35, -0.05; p-value=0.0103) and deaths (-0.04, 95% CI: -0.05, -0.03; p-value=<0.0001). Conversely, prescription opioids for pain management modestly increased deaths (0.0008, 95% CI: 0.0002, 0.0015; p-value=0.0157) per 100,000 population, respectively. Except for a few treated PHU/synthetic control pairs, disaggregate results were congruent with overall findings. CONCLUSION: Booth-hours had no population-level effect on opioid-related overdose ED visit, hospitalization, or death rates.

Evaluating the population-level effects of overdose prevention sites and supervised consumption sites in British Columbia, Canada: Controlled interrupted time series.

BACKGROUND: On 14 April 2016, British Columbia's Provincial Medical Health Officer declared the overdose crisis a public health emergency, sanctioning the implementation of new overdose prevention sites (OPS) and supervised consumption sites (SCS) across the province. METHODS: We used the BC Centre for Disease Control's Provincial Overdose Cohort of all overdose events between 1 January 2015 and 31 December 2017 to evaluate the population-level effects of OPSs and SCSs on acute health service use and mortality. We matched local health areas (LHA) that implemented any site with propensity score matched controls and conducted controlled interrupted time series analysis. RESULTS: During the study period, twenty-five OPSs and SCSs opened across fourteen of British Columbia's 89 LHAs. Results from analysis of LHAs with matched controls (i.e. excluding Vancouver DTES) were mixed. Significant declines in reported overdose events, paramedic attendance, and emergency department visits were observed. However, there were no changes to trends in monthly hospitalization or mortality rates. Extensive sensitivity analyses found these results persisted. CONCLUSIONS: We found OPSs and SCSs reduce opioid-related paramedic attendance and emergency department visit rates but no evidence that they reduce local hospitalization or mortality rates.

Relative effectiveness of medications for opioid-related disorders: A systematic review and network meta-analysis of randomized controlled trials.

INTRODUCTION: Several pharmacotherapeutic interventions are available for maintenance treatment for opioid-related disorders. However, previous meta-analyses have been limited to pairwise comparisons of these interventions, and their efficacy relative to all others remains unclear. Our objective was to unify findings from different healthcare practices and generate evidence to strengthen clinical treatment protocols for the most widely prescribed medications for opioid-use disorders. METHODS: We searched Medline, EMBASE, PsycINFO, CENTRAL, and ClinicalTrials.gov for all relevant randomized controlled trials (RCT) from database inception to February 12, 2022. Primary outcome was treatment retention, and secondary outcome was opioid use measured by urinalysis. We calculated risk ratios (RR) and 95% credible interval (CrI) using Bayesian network meta-analysis (NMA) for available evidence. We assessed the credibility of the NMA using the Confidence in Network Meta-Analysis tool. RESULTS: Seventy-nine RCTs met the inclusion criteria. Due to heterogeneity in measuring opioid use and reporting format between studies, we conducted NMA only for treatment retention. Methadone was the highest ranked intervention (Surface Under the Cumulative Ranking [SUCRA] = 0.901) in the network with control being the lowest (SUCRA = 0.000). Methadone was superior to buprenorphine for treatment retention (RR = 1.22; 95% CrI = 1.06-1.40) and buprenorphine superior to naltrexone (RR = 1.39; 95% CrI = 1.10-1.80). However, due to a limited number of high-quality trials, confidence in the network estimates of other treatment pairs involving naltrexone and slow-release oral morphine (SROM) remains low. CONCLUSION: All treatments had higher retention than the non-pharmacotherapeutic control group. However, additional high-quality RCTs are needed to estimate more accurately the extent of efficacy of naltrexone and SROM relative to other medications. For pharmacotherapies with established efficacy profiles, assessment of their long-term comparative effectiveness may be warranted. TRIAL REGISTRATION: This systematic review has been registered with PROSPERO (https://www.crd.york.ac.uk/prospero) (identifier CRD42021256212).

Chemsex and incidence of sexually transmitted infections among Canadian pre-exposure prophylaxis (PrEP) users in the l'Actuel PrEP Cohort (2013-2020).

OBJECTIVES: Use of illicit substances during sex (chemsex) may increase transmission of HIV and other STIs. Pre-exposure prophylaxis (PrEP) is highly effective at preventing HIV transmission, providing an important prevention tool for those who practise chemsex. However, it does not prevent acquisition of other STIs. We aim to examine the impact of chemsex on STI incidence among gay, bisexual and other men who have sex with men (gbMSM), and transgender women using PrEP in Montréal, Canada. METHODS: We linked baseline sociodemographic and behavioural data with follow-up STI testing from 2013 to 2020 among PrEP users in the l'Actuel PrEP Cohort (Canada). Focusing on the 24 months following PrEP initiation, we estimated the effect of chemsex reported at baseline on cumulative incidence of gonorrhoea and chlamydia using Kaplan-Meier curves and survival analyses. We investigated the role of polysubstance use and effect modification by sociodemographic factors. RESULTS: There were 2086 clients (2079 cisgender gbMSM, 3 transgender gbMSM, 4 transgender women) who initiated PrEP, contributing 1477 years of follow-up. There were no incident HIV infections among clients on PrEP. Controlling for sociodemographic confounders, clients reporting chemsex at baseline had a 32% higher hazard of gonorrhoea/chlamydia diagnosis (adjusted HR=1.32; 95% CI: 1.10 to 1.57), equivalent to a risk increase of 8.9 percentage points (95% CI: 8.5 to 9.4) at 12 months. The effect was greater for clients who reported polysubstance use (adjusted HR=1.51; 95% CI: 1.21 to 1.89). The strength of the effect of chemsex on STI incidence varied by age, education and income. CONCLUSION: Among PrEP users, chemsex at baseline was linked to increased incidence of gonorrhoea and chlamydia. This effect was stronger for people reporting multiple chemsex substances. The high STI incidence among gbMSM who report chemsex highlights the importance of PrEP for this population and the need for integrated services that address the complexities of sexualised substance use.

Comorbidities and Medical Complications in Hospitalized Subarachnoid Hemorrhage Patients.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (SAH) remains a devastating condition with a case fatality of 36% at 30 days. Risk factors for mortality in SAH patients include patient demographics and the severity of the neurological injury. Pre-existing conditions and non-neurological medical complications occurring during the index hospitalization are also risk factors for mortality in SAH. The magnitude of the effect on mortality of pre-existing conditions and medical complications, however, is less well understood. In this study, we aim to determine the effect of pre-existing conditions and medical complications on SAH mortality. METHODS: For a 25% random sample of the Greater Montreal Region, we used discharge abstracts, physician billings, and death certificate records, to identify adult patients with a new diagnosis of non-traumatic SAH who underwent cerebral angiography or surgical clipping of an aneurysm between 1997 and 2014. RESULTS: The one-year mortality rate was 14.76% (94/637). Having ≥3 pre-existing conditions was associated with increased one-year mortality OR 3.74, 95% CI [1.25, 9.57]. Having 2, or ≥3 medical complications was associated with increased one-year mortality OR, 2.42 [95% CI 1.25-4.69] and OR, 2.69 [95% CI 1.43-5.07], respectively. Sepsis, respiratory failure, and cardiac arrhythmias were associated with increased one-year mortality. Having 1, 2, or ≥3 pre-existing conditions was associated with increased odds of having medical complications in hospital. CONCLUSIONS: Pre-existing conditions and in-hospital non-neurological medical complications are associated with increased one-year mortality in SAH. Pre-existing conditions are associated with increased medical complications.

Evaluating Montréal's harm reduction interventions for people who inject drugs: protocol for observational study and cost-effectiveness analysis.

INTRODUCTION: The main harm reduction interventions for people who inject drugs (PWID) are supervised injection facilities, needle and syringe programmes and opioid agonist treatment. Current evidence supporting their implementation and operation underestimates their usefulness by excluding skin, soft tissue and vascular infections (SSTVIs) and anoxic/toxicity-related brain injury from cost-effectiveness analyses (CEA). Our goal is to conduct a comprehensive CEA of harm reduction interventions in a setting with a large, dispersed, heterogeneous population of PWID, and include prevention of SSTVIs and anoxic/toxicity-related brain injury as measures of benefit in addition to HIV, hepatitis C and overdose morbidity and mortalities averted. METHODS AND ANALYSIS: This protocol describes how we will develop an open, retrospective cohort of adult PWID living in Québec between 1 January 2009 and 31 December 2020 using administrative health record data. By complementing this data with non-linkable paramedic dispatch records, regional monthly needle and syringe dispensation counts and repeated cross-sectional biobehavioural surveys, we will estimate the hazards of occurrence and the impact of Montréal's harm reduction interventions on the incidence of drug-use-related injuries, infections and deaths. We will synthesise results from our empirical analyses with published evidence to simulate infections and injuries in a hypothetical population of PWID in Montréal under different intervention scenarios including current levels of use and scale-up, and assess the cost-effectiveness of each intervention from the public healthcare payer's perspective. ETHICS AND DISSEMINATION: This study was approved by McGill University's Institutional Review Board (Study Number: A08-E53-19B). We will work with community partners to disseminate results to the public and scientific community via scientific conferences, a publicly accessible report, op-ed articles and open access peer-reviewed journals.

Can hepatitis C elimination targets be sustained among people who inject drugs post-2030?

BACKGROUND: In high-income countries, people who inject drugs (PWID) are a priority population for eliminating hepatitis C virus (HCV) by 2030. Despite evidence informing micro-elimination strategies, little is known regarding efforts needed to maintain elimination targets in populations with ongoing acquisition risks. This model-based study investigates post-elimination transmission dynamics of HCV and HIV among PWID under different scenarios where harm reduction interventions and HCV testing and treatment are scaled-down. METHODS: We calibrated a dynamic compartmental model of concurrent HCV and HIV transmission among PWID in Montréal (Canada) to epidemiological data (2003-2018). We then simulated achieving the World Health Organization elimination targets by 2030. Finally, we assessed the impact of four post-elimination scenarios (2030-2050): 1) scaling-down testing, treatment, opioid agonist therapy (OAT), and needle and syringe programs (NSP) to pre-2020 levels; 2) only scaling-down testing and treatment; 3) suspending testing and treatment, while scaling down OAT and NSP to pre-2020 levels; 4) suspending testing and treatment and maintaining OAT and NSP coverage required for elimination. RESULTS: Scaling down interventions to pre-2020 levels (scenario 1) leads to a modest rebound in chronic HCV incidence from 2.4 to 3.6 per 100 person-years by 2050 (95% credible interval - CrI: 0.8-7.2). When only scaling down testing and treatment (scenario 2), chronic HCV incidence continues to decrease. In scenario 3 (suspending treatment and scaling down OAT and NSP), HCV incidence and mortality rapidly increase to 11.4 per 100 person-years (95%CrI: 7.4-15.5) and 3.2 per 1000 person-years (95%CrI: 2.4-4.0), respectively. HCV resurgence was mitigated in scenario 4 (maintaining OAT and NSP) as compared to scenario 3. All scenarios lead to decreases in the proportion of reinfections among incident cases and have little impact on HIV incidence and HIV-HCV coinfection prevalence. CONCLUSION: Despite ongoing transmission risks, HCV incidence rebounds slowly after 2030 under pre-2020 testing and treatment levels. This is heightened by maintaining high-coverage harm reduction interventions. Overall, sustaining elimination would require considerably less effort than achieving it.

Chemsex practices and pre-exposure prophylaxis (PrEP) trajectories among individuals consulting for PrEP at a large sexual health clinic in Montréal, Canada (2013-2020).

INTRODUCTION: Chemsex among gay, bisexual and other men who have sex with men (gbMSM) has raised public health concerns because of its association with sexual behaviours that can increase transmission of sexually transmitted infections, including HIV. Pre-exposure prophylaxis (PrEP) is highly effective at blocking HIV acquisition, addressing important prevention needs among individuals practicing chemsex. This study aims to improve our understanding of chemsex practices and PrEP trajectories of gbMSM and transgender women consulting for PrEP. METHODS: We used data from the PrEP cohort of Clinique médicale l'Actuel, a major sexual health clinic in Montréal. We describe the sociodemographic profile of clients consulting for PrEP, characterize chemsex and polysubstance use trends over time, and evaluate PrEP trajectories using Kaplan-Meier curves. RESULTS: Among 2923 clients who consulted for PrEP between 2013-2020 (2910 cisgender gbMSM, 6 transgender gbMSM, 7 transgender women), 24 % reported chemsex in the past year and 13 % reported polysubstance use. The most common chemsex substances were ecstasy (14 %), GHB (13 %), and cocaine (12 %). The proportion of clients reporting chemsex and polysubstance use decreased over time. In both the chemsex and no-chemsex group, 73 % of clients initiated PrEP. The median time to discontinuation was similar between the chemsex (6.5 months; 95 %CI: 5.3-7.2) and no-chemsex group (6.9 months; 95 %CI: 6.3-7.5). CONCLUSION: Chemsex is not a barrier to PrEP initiation or persistence. However, these results suggest a high prevalence of chemsex among gbMSM consulting for PrEP, highlighting the need for services addressing the intersection of sexual health and substance use for this population.

Opioid prescribing practice standard in British Columbia, Canada: Rationale, controversies, and directions.

British Columbia (BC) has been the hardest hit province in Canada's ongoing overdose epidemic. As part of the province-level response, the College of Physicians and Surgeons of British Columbia (CPSBC) implemented the "Safe Prescribing of Drugs with Potential for Misuse/Diversion" practice standard in June 2016. The practice standard established specific dose and quantity thresholds for opioid prescribing as professional and ethical conduct expectations for physicians in BC. This supply side intervention was based on expert interpretation of available evidence of non-superiority of opioid treatments to non-opioid treatments. However, the potential for misinterpretation of dosage ceiling thresholds and the negative repercussions to patients that could follow raised concerns among both physicians and patients. We provide a comprehensive overview of the rationale, early impact, controversies, and potential shortcomings of the CPSBC's practice standard.

Evaluating the intended and unintended consequences of opioid-prescribing interventions on primary care in British Columbia, Canada: protocol for a retrospective population-based cohort study.

INTRODUCTION: Between 2015 and 2018, there were over 40 000 opioid-related overdose events and 4551 deaths among residents in British Columbia (BC). During this time the province mobilised a variety of policy levers to encourage physicians to expand access to opioid agonist treatment and the College of Physicians and Surgeons of British Columbia (CPSBC) released a practice standard establishing legally enforceable minimum thresholds of professional behaviour in the hopes of curtailing overdose events. Our goal is to conduct a comprehensive investigation of the intended and unintended consequences of these policy changes. Specifically, we aim to understand the effects of these measures on physician prescribing behaviours, identify physician characteristics associated with uptake of the new measures, and measure the effects of the policy changes on patients' access to quality primary care. METHODS AND ANALYSIS: This is a population-level, retrospective cohort study of all BC primary care physicians who prescribed any opioid medication for opioid-use disorder or chronic non-cancer pain during the study period, and their patients. The study period is 1 January 2013-31 December 2018, with a 1-year wash-in period (1 January 2012-31 December 2012) to exclude patients who initiated long-term opioid treatment prior to our study period or whose pain type (ie, 'chronic non-cancer', 'acute', 'cancer or palliative', or 'other') cannot be confirmed. The project combines five administrative health datasets under the authority of the BC Ministry of Health, with the CPSBC's Physician Registry, BC Cancer Agency's Cancer Registry and Vital Statistics' Mortality data. We will create measures of prescribing concordance, access, continuity, and comprehensiveness to assess primary care delivery and quality at both the physician and patient level. We will use generalised estimating equations, interrupted time series, mixed effects models, and funnel plots to identify factors related to changes in prescribing and evaluate the impact of the changes to prescribing policies. Results will be reported using appropriate Enhancing the QUAlity and Transparency Of health Research guidelines (eg, STrengthening the Reporting of OBservational studies in Epidemiology). ETHICS AND DISSEMINATION: This study has been approved by McGill University's Institutional Review Board (#A11-M55-19A), and the University of British Columbia's Research Ethics Board (#H19-03537). We will disseminate results via a combination of open access peer-reviewed journal publications, conferences, lay summaries and OpEds.

Determining the long-term health burden and risk of sequelae for 14 foodborne infections in British Columbia, Canada: protocol for a retrospective population-based cohort study.

INTRODUCTION: Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality, for the population of British Columbia, Canada (~4.7 million). METHODS AND ANALYSIS: We will conduct a population-based retrospective cohort study of the British Columbia provincial population, over a 10-year study period (1 January 2005 to 31 December 2014). Exposure is defined as a provincially reported illness caused by Clostridium botulinum, Campylobacter, Cryptosporidium, Cyclospora, Giardia, hepatitis A virus, Listeria, non-typhoidal Salmonella spp, Salmonella Typhi, Salmonella Paratyphi, Shiga toxin-producing Escherichia coli, Shigella, Vibrio parahaemolyticus or Yersinia (excluding pestis). We will link individual-level longitudinal data from eight province-wide administrative health and reportable disease databases that include physician visits, hospitalisations and day surgeries, deaths, stillbirths, prescription medications (except those to treat HIV) and reportable foodborne diseases. Using these linked databases, we will investigate the likelihood of various sequelae and death. Hazard models will be used to estimate the risk of outcomes and their association with the type of foodborne infection. Epidemiological analyses will be conducted to determine the progression of illness and the fraction of sequelae attributable to specific foodborne infections. Economic analyses will assess the consequent direct healthcare costs. ETHICS AND DISSEMINATION: This study has been approved by a University of Waterloo Research Ethics Committee (no 30645), the University of British Columbia Behavioral Research Ethics Board (no H16-00021) and McGill University's Institutional Review Board (no A03-M12-19A). Results will be disseminated via presentations to academics, public health practitioners and knowledge users, and publication in peer-reviewed journals. Where such publications are not open access, manuscripts will also be available via the University of Waterloo's Institutional Repository (https://uwspace.uwaterloo.ca).

Geographic variation in the costs of medical care for people living with HIV in British Columbia, Canada.

BACKGROUND: Regional variation in medical care costs can indicate heterogeneity in clinical practice, inequities in access, or inefficiencies in service delivery. We aimed to estimate regional variation in medical costs for people living with HIV (PLHIV), adjusting for demographics and case-mix. METHODS: We conducted a retrospective cohort study using linked health administrative databases of PLHIV, from 2010 to 2014, in British Columbia (BC), Canada. Quarterly health care costs (2018 CAD) were derived from inpatient, outpatient, prescription drugs, antiretroviral therapy (ART), and HIV diagnostics. We used a two-part model with a logit link for the probability of incurring costs, and a log link and gamma distribution for observations with positive costs. We also estimated quarterly utilization rates for hospitalization-, physician billing- and prescription drug-days. Primary variables were indicators of individuals' Health Service Delivery Area (HSDA). We adjusted cost and utilization estimates for demographic characteristics, HIV-disease progression, and comorbidities. RESULTS: Our cohort included 9577 PLHIV (median age 45.5 years, 80% male). Adjusted total quarterly costs for all 16 HSDAs were within 20% of the provincial mean, 8/16 for hospitalization costs, 16/16 for physician billing costs and 10/16 for prescription drug costs. Northern Interior and Northeast HSDAs had 38 and 44% lower quarterly non-ART prescription drug costs, and 2 and 5% higher quarterly inpatient costs, respectively. CONCLUSIONS: We observed limited variation in medical care costs and utilization among PLHIV in BC. However, lower levels of outpatient care and higher levels of inpatient care indicate possible barriers to accessing care among PLHIV in the most rural regions of the province.