Towards cross-Canada monitoring of the unregulated street drug supply.

BACKGROUND: The well-being of people who use drugs (PWUD) continues to be threatened by substances of unknown type or quantity in the unregulated street drug supply. Current efforts to monitor the drug supply are limited in population reach and comparability. This restricts capacity to identify and develop measures that safeguard the health of PWUD. This study describes the development of a low-barrier system for monitoring the contents of drugs in the unregulated street supply. Early results for pilot sites are presented and compared across regions. METHODS: The drug content monitoring system integrates a low-barrier survey and broad spectrum urine toxicology screening to compare substances expected to be consumed and those actually in the drug supply. The system prototype was developed by harm reduction pilot projects in British Columbia (BC) and Montreal with participation of PWUD. Data were collected from harm reduction supply distribution site clients in BC, Edmonton and Montreal between May 2018-March 2019. Survey and urine toxicology data were linked via anonymous codes and analyzed descriptively by region for trends in self-reported and detected use. RESULTS: The sample consisted of 878 participants from 40 sites across 3 regions. Reported use of substances, their detection, and concordance between the two varied across regions. Methamphetamine use was reported and detected most frequently in BC (reported: 62.8%; detected: 72.2%) and Edmonton (58.3%; 68.8%). In Montreal, high concordance was also observed between reported (74.5%) and detected (86.5%) cocaine/crack use. Among those with fentanyl detected, the percentage of participants who used fentanyl unintentionally ranged from 36.1% in BC, 78.6% in Edmonton and 90.9% in Montreal. CONCLUSIONS: This study is the first to describe a feasible, scalable monitoring system for the unregulated drug supply that can contrast expected and actual drug use and compare trends across regions. The system used principles of flexibility, capacity-building and community participation in its design. Results are well-suited to meet the needs of PWUD and inform the local harm reduction services they rely on. Further standardization of the survey tool and knowledge mobilization is needed to expand the system to new jurisdictions.

The need for treatment scale-up to impact HCV transmission in people who inject drugs in Montréal, Canada: a modelling study.

BACKGROUND: HCV transmission remains high in people who inject drugs (PWID) in Montréal. New direct-acting antivirals (DAAs), highly effective and more tolerable than previous regimens, make a "Treatment as Prevention" (TasP) strategy more feasible. This study assesses how improvements in the cascade of care could impact hepatitis C burden among PWID in Montréal. METHODS: We used a dynamic model to simulate HCV incidence and prevalence after 10 years, and cirrhosis complications after 10 and 40 years. Eight scenarios of improved cascade of care were examined. RESULTS: Using a baseline incidence and prevalence of 22.1/100 person-years (PY) and 53.1%, implementing the current cascade of care using DAAs would lead to HCV incidence and prevalence estimates at 10 years of 9.4/100PY and 55.8%, respectively. Increasing the treatment initiation rate from 5%/year initially to 20%/year resulted in large decreases in incidence (6.4/100PY), prevalence (36.6%), and cirrhosis complications (-18%/-37% after 10/40 years). When restricting treatment to fibrosis level ≥ F2 instead of F0 (reference scenario), such decreases in HCV occurrence were unreachable. Improving the whole cascade of care led to the greatest effect by halving both the incidence and prevalence at 10 years, and the number of cirrhosis complications after 40 years. CONCLUSIONS: The current level of treatment access in Montréal is limiting a massive decrease in hepatitis C burden among PWID. A substantial treatment scale-up, regardless of fibrosis level, is necessary. While improving the rest of the cascade of care is necessary to optimize a TasP strategy and control the HCV epidemic, a treatment scale-up is first needed.

Sex Work as an Emerging Risk Factor for Human Immunodeficiency Virus Seroconversion Among People who Inject Drugs in the SurvUDI Network.

BACKGROUND: Recent analyses have shown an emerging positive association between sex work and human immunodeficiency virus (HIV) incidence among people who inject drugs (PWIDs) in the SurvUDI network. METHODS: Participants who had injected in the past 6 months were recruited across the Province of Quebec and in the city of Ottawa, mainly in harm reduction programs. They completed a questionnaire and provided gingival exudate for HIV antibody testing. The associations with HIV seroconversion were tested with a Cox proportional hazard model using time-dependent covariables including the main variable of interest, sexual activity (sex work; no sex work; sexually inactive). The final model included significant variables and confounders of the associations with sexual activity. RESULTS: Seventy-two HIV seroconversions were observed during 5239.2 person-years (py) of follow-up (incidence rates: total = 1.4/100 py; 95% confidence interval [CI], 1.1-1.7; sex work = 2.5/100 py; 95% CI, 1.5-3.6; no sex work = 0.8/100 py; 95% CI, 0.5-1.2; sexually inactive = 1.8/100 py; 95% CI, 1.1-2.5). In the final multivariate model, HIV incidence was significantly associated with sexual activity (sex work: adjusted hazard ratio [AHR], 2.19; 95% CI, 1.13-4.25; sexually inactive: AHR, 1.62; 95% CI, 0.92-2.88), and injection with a needle/syringe used by someone else (AHR, 2.84; 95% CI, 1.73-4.66). CONCLUSIONS: Sex work is independently associated with HIV incidence among PWIDs. At the other end of the spectrum of sexual activity, sexually inactive PWIDs have a higher HIV incidence rate, likely due to more profound dependence leading to increased vulnerabilities, which may include mental illness, poverty, and social exclusion. Further studies are needed to understand whether the association between sex work and HIV is related to sexual transmission or other vulnerability factors.

Nonmedical Use of Prescription Medication Among Adolescents Using Drugs in Quebec.

OBJECTIVE: To determine the prevalence and factors associated with nonmedical use of prescription medication (NMUPM) among adolescents who use drugs (ages 12 to 17 years) in Quebec. METHOD: Secondary data analyses were carried out with data from a 6-month study, namely, the 2010-2011 Quebec Health Survey of High School Students-a large-scale survey that sought to gain a better understanding of the health and well-being of young Quebecers in high school. Bivariate and multivariate logistic regression analyses were conducted to study NMUPM among adolescents who use drugs, according to sociodemographic characteristics, peer characteristics, health indicators (anxiety, depression, or attention-deficit disorder [ADD] with or without hyperactivity), self-competency, family environment, and substance use (alcohol and drug use) factors. RESULTS: Among adolescents who had used drugs in the previous 12 months, 5.4% (95% CI 4.9% to 6.0%) reported NMUPM. Based on multivariate analyses, having an ADD (adjusted odds ratio [AOR] 1.47; 95% CI 1.13 to 1.91), anxiety disorder (AOR 2.14; 95% CI 1.57 to 2.92), low self-esteem (AOR 1.62; 95% CI 1.26 to 2.08), low self-control (AOR 1.95; 95% CI 1.55 to 2.45), low parental supervision (AOR 1.43; 95% CI 1.11 to 1.83), regular alcohol use (AOR 1.72; 95% CI 1.36 to 2.16), and polysubstance use (AOR 4.09; 95% CI 3.06 to 5.48) were associated with increased odds of reporting NMUPM. CONCLUSIONS: The observed prevalence of NMUPM was lower than expected. However, the associations noted with certain mental health disorders and regular or heavy use of other psychoactive substances are troubling. Clinical implications are discussed.

Breakthrough cases of mpox: One-dose vaccination is associated with milder clinical manifestations.

BACKGROUND: Very few studies have investigated the effectiveness of vaccination in decreasing the severity of breakthrough mpox. Our goal was to estimate the strength of the associations between recent mpox vaccination with MVA-BN and various clinical manifestations of the disease. METHODS: Telephone interviews using standardized questionnaires, upon notification and 28 days later, of the 403 persons with mpox reported to Montreal Public Health in 2022. MVA-BN vaccination data were obtained from the provincial immunization registry. The main outcomes were numbers of skin lesions and body sites affected, other clinical manifestations (OCM) compatible with mpox, complications, and hospitalization. FINDINGS: 155 persons with mpox (39% of 403) had received 1 dose of vaccine at least 14 days before symptom onset. One-dose vaccination, adjusting for age and HIV status, was significantly associated with fewer lesions, sites affected with lesions, and OCMs. HIV-positive persons with breakthrough mpox reported significantly more lesions, sites affected, and OCMs at initial interview, than HIV-negative ones. However, vaccination was associated with a lower risk of all outcomes to the same degree irrespective of HIV status. INTERPRETATION: One dose of MVA-BN vaccine was about 60% effective in decreasing the frequency and extent of clinical manifestations, among both HIV-positive and HIV-negative persons with breakthrough mpox. Beyond preventing infection, mpox vaccination can be promoted to reduce clinical manifestations in persons at risk for mpox, even if HIV+ . FUNDING: This work used data obtained as part of Montreal Public Health's 2022 mpox outbreak response and received no external funding.

HIV and HCV seroincidence, associated factors and drug use in people who inject drugs, SurvUDI network, eastern central Canada, 1995-2020.

BACKGROUND: The SurvUDI network is a biobehavioural survey among people who inject drugs (PWID) in Eastern Central Canada. OBJECTIVES: The objectives were to describe HIV and HCV seroincidence trends, associated factors and changes in drug use behaviours. METHODS: The network was initiated in 1995 and targets hard-to-reach, mostly out-of- treatment PWID. Participants were recruited mostly in harm reduction programs, completed an interviewer-administered questionnaire, provided a sample of gingival exudate for HIV and HCV antibody testing and were identified using an encrypted code allowing identification of multiple participations. Time trends were examined for HIV and HCV seroincidence, selected characteristics and behaviours. Cox proportional hazard regression was used to examine factors associated to HIV and HCV seroincidence. RESULTS: Between January 1995 and March 2020, 15,907 individuals have completed 31,051 questionnaires. HIV seroincidence decreased significantly from 5.0 per 100 person-years (p-y) in 1995 to 0.4 per 100 p-y in 2018. HCV seroincidence also decreased significantly between 1998 and 2011. The use of syringes already used by someone else decreased significantly, from 43.4 % in 1995 to 12.4 % in 2019, as well as the use of equipment other than syringe already used by someone else. Cocaine/crack injection decreased significantly while "opioids other than heroin" injection increased, concomitant to daily injection. Injection with syringes already used by someone else and cocaine as the most often injected drug were significantly associated with HIV seroincidence (1995-2020). Injected opioid other than heroin, injected cocaine/crack, injected 100 or more times in the past month, injected for less than 3 years, injected with syringes or equipment already used by someone else, injected with someone else and reported client sex partners were significantly associated with HCV seroincidence (2004-2020). CONCLUSION: HIV seroincidence and syringe/equipment sharing behaviour trends are encouraging, but HCV seroincidence remains high.

Changes in supervised consumption site use and emergency interventions in Montréal, Canada in the first twelve months of the COVID-19 pandemic: An interrupted time series study.

BACKGROUND: The COVID-19 pandemic has impacted supervised consumption site (SCS) operations in Montréal, Canada, potentially including changes in SCS visits, on-site emergency interventions, injection of specific drugs, and distribution of harm reduction materials. METHOD: We used administrative data from all four Montréal SCS from 1 March 2018 - 28 February 2021 to conduct an interrupted time series study with 13 March 2020 as the intervention point. We employed segmented regression using generalised least squares fit by maximum likelihood. We analysed monthly SCS visits and materials distributed as counts, and emergency interventions and drugs injected as proportions of visits. RESULTS: SCS visits (level change = -1,286; 95% CI [-1,642, -931]) and the proportion of visits requiring emergency intervention (level = -0.27% [-0.47%, -0.06%]) decreased immediately in March 2020, followed by an increasing trend in emergency interventions (slope change = 0.12% [0.10%, 0.14%]) over the ensuing 12 months. Over the same period, the proportion of injections involving opioids increased (slope = 0.05% [0.03%, 0.07%]), driven by increasing pharmaceutical opioid and novel synthetic opioid injections. Novel synthetic opioids were the drugs most often injected prior to overdose. The proportion of injections involving unregulated amphetamines increased immediately (level = 7.83% [2.93%, 12.73%]), then decreased over the next 12 months (slope = -1.86% [-2.51%, -1.21%]). There was an immediate increase in needle/syringe distribution (level = 16,552.81 [2,373, 30,732]), followed by a decreasing trend (slope = -2,398 [-4,218, -578]). There were no changes in pre-existing increasing trends in naloxone or fentanyl test strip distribution. CONCLUSION: Reduced SCS use and increasing emergency interventions at SCS are cause for serious concern. Findings suggest increased availability of novel synthetic opioids in Montréal, heightening overdose risk.

The challenge of understanding mortality changes among street youth.

According to a cohort study conducted in Montréal, Québec from 1995 to 2000, the mortality rate among street youth was 921/100,000 person-years. Several new community initiatives aiming to increase access to housing and to social and health services for the homeless were implemented in the city between 2000 and 2003. This study aims to update the mortality rate estimate for the period 2001-2006 and to examine factors that could explain a difference between rates, if any. A second cohort study was conducted between 2001 and 2006. The Cohort 2 mortality rate was computed and compared with the Cohort 1 rate. Several analyses were then carried out: (1) mortality rates in the general population were compared with street youth rates using standardized mortality ratios (SMR); (2) Cohorts 1 and 2 distributions of risk factors for mortality were examined, and their effects were assessed using multivariate proportional hazards regression analyses carried out on a combined Cohorts 1 and 2 dataset. Mortality rate among street youth decreased by 79% while it declined by only 19% in the general population; the SMR for Cohort 1 was higher than for Cohort 2 (11.6 versus 3.0). Multivariate proportional hazards regression analyses yielded estimates that were close to the model's estimates based on Cohort 1 data only, and participation in Cohort 1 was an independent predictor of mortality, with an adjusted hazard ratio of 9.0. The mortality decline cannot be completely explained by a similar decrease among the general population or by a difference in distribution of risk factors for mortality between the two cohorts. Field workers suggested that the decrease in heroin consumption they had observed in the streets might have contributed to the mortality decline. We then performed additional analyses which showed that even though the proportion of street youth currently using heroin decreased significantly between 1995 and 2005, the association between heroin use and mortality was not significant (adjusted hazard ratio of 0.9; 95% CI, 0.4 to 2.3). It seems that various factors could have contributed to the decline in mortality rates among street youth, one plausible factor being the implementation of new services for the homeless. This study underscores the importance of monitoring risky behaviors among vulnerable populations to ensure that morbidity and mortality data among these populations is correctly interpreted. Setting up a system to monitor the drug market could improve the quality of information collected.

Upsurge of chlamydial reinfection in a large Canadian city: an indication of suboptimal chlamydia screening practices?

OBJECTIVES: Given the limited knowledge on chlamydial reinfection (CR) in Canada, we examined the extent and predictors of CR in Montréal, a large Canadian city. METHODS: We retrospectively studied all Montréal residents aged > or =10 years for whom > or =1 laboratory-confirmed chlamydial infection was reported to the public health department between 1988 and 2007 (n = 44,580). Each person was passively followed for two years after baseline infection or until reinfection. Socio-demographic factors and histories of other notifiable diseases were examined as potential predictors. Cox multivariate regression was used to model the time to CR. Survival analyses were stratified by age group (<25 vs. > or =25 years). RESULTS: We estimated an overall two-year CR rate of 6.4%, an incidence density of 3.5 per 100 person-years, and a median time to reinfection of nine months. CR significantly increased over time. Among persons <25 years, reinfection was significantly more likely among females [adjusted hazard ratio (AHR): 1.58] and younger participants (10-14 years: AHR: 2.98; 15-19 years: AHR: 1.81). Residing within the South Central sector was deleterious for six months following initial infection after which it became protective. Among persons > or =25 years, a history of sexually transmitted infections increased the risk of reinfection (AHR: 1.79). CONCLUSION: CR is a significant and growing problem in Montreal. The current recommendation for a single repeat screening six months posttreatment might be usefully complemented with additional screenings. Our results also underscore the importance of screening high-risk populations, particularly young women.

Impact of sex work on risk behaviours and their association with HIV positivity among people who inject drugs in Eastern Central Canada: cross-sectional results from an open cohort study.

OBJECTIVES: The objectives of this study were: (1) to examine the correlates of HIV positivity among participants who injected drugs and engaged in sex work (PWID-SWs) in the SurvUDI network between 2004 and 2016, after stratification by sex, and (2) to compare these correlates with those of sexually active participants who did not engage in sex work (PWID non-SWs). DESIGN AND SETTING: This biobehavioural survey is an open cohort of services where participants who had injected in the past 6 months were recruited mainly through harm reduction programmes in Eastern Central Canada. PARTICIPANTS: Data from 5476 participants (9223 visits in total; 785 not included in multivariate analyses due to missing values) were included. METHODS: Participants completed an interviewer-administered questionnaire and provided saliva samples for anti-HIV antibody testing. Generalised estimating equations taking into account multiple participations were used. RESULTS: Baseline HIV prevalence was higher among SWs compared with non-SWs (women: 13.0% vs 7.7%; P<0.001, and men: 17.4% vs 10.8%; P<0.001). PWID-SWs were particularly susceptible to HIV infection as a result of higher levels of vulnerability factors and injection risk behaviours. They also presented different risk-taking patterns than their non-SWs counterparts, as shown by differences in correlates of HIV positivity. Additionally, the importance of sex work for HIV infection varies according to gender, as suggested by a large proportion of injection risk behaviours associated with HIV among women and, conversely, a stronger association between sexual behaviours and HIV positivity observed among men. CONCLUSION: These results suggest that sex work has an impact on the risk of HIV acquisition and that risk behaviours vary according to gender. Public health practitioners should take those specificities into account when designing HIV prevention interventions aimed at PWIDs.

Trends in injection drug use behaviors over 10 years among street youth.

OBJECTIVES: To determine the temporal trends of initiation into injection drug use, current injection, and recent receptive sharing of injection paraphernalia among street youth. DESIGN: Data from two cohort studies conducted between 1995 and 2005 were combined. METHODS: Recruitment was done on an ongoing basis. Interviews were performed semi-annually. Overall and annual drug injection incidence rates were calculated with the person-time method. Poisson regression was used to assess the predictive power of calendar year on incidence rate. Generalized estimating equations (GEE) were used to assess linear trends in current injection among street youth and in recent receptive sharing of syringe and other injection paraphernalia among current injection drug users. RESULTS: By 31 March 2005, 1633 subjects had completed 8875 questionnaires. Most subjects were born in Canada (94%), their mean age at entry was 20 years, 68% were boys and almost half (44%) had injected drugs before recruitment. Among 778 never injectors at entry, 130 subjects initiated injection in 1898 person-years of follow-up (incidence rate: 6.8 per 100 person-years). When controlling for age, calendar year was not a significant predictor of incidence rate. Prevalence of current injection was stable (around 30%). Odds of both sharing behaviors decreased by approximately 10% per year. CONCLUSIONS: In addition to injection paraphernalia sharing reduction efforts, interventions aimed at preventing initiation into injection drug use among high-risk youth are needed.

Drug use practices among people who inject drugs in a context of drug market changes: Challenges for optimal coverage of harm reduction programs.

BACKGROUND: Until the early 2000s, people who inject drugs (PWID) in Québec had mainly been injecting powder cocaine and heroin. Since then, ethnographic studies have shown that the drug market has diversified, with crack and prescription opioids (PO) becoming increasingly available. This could have led to changes in drug use practices among PWID. The objectives of our study were to examine annual trends in injection of different drugs, crack smoking and frequent injection (FI), as well as relationships between injected drugs and FI. METHODS: PWID are participants in the ongoing Québec SurvUDI surveillance system. PWID (past 6 months) were recruited in 2 urban and 6 semi-urban/rural sites. Each visit included a structured interview addressing drug use behaviours. Analyses were carried out using GEE methods. For trend analyses (2003-2014) on drugs and FI (number of injections≥upper quartile, previous month), the first annual interview was selected for PWID with multiple participations per year. Analyses on associations between FI and types of injected drugs were based on all interviews (2004-2014). RESULTS: Crack/cocaine and heroin injection declined significantly, with prevalence ratios (PR) per year of 0.983 [95% confidence interval (CI): 0.980-0.986] and 0.979 (95% CI: 0.969-0.990), while PO injection [PR=1.052 (1.045-1.059)], crack smoking [PR=1.006 (1.001-1.012)], and FI (≥120 injections, previous month) significantly increased [PR=1.015 (1.004-1.026)]. Compared to PWID who injected crack/cocaine±other drugs, the proportion of PWID reporting FI was higher among those who injected PO+heroin/speedball, crack/cocaine or other drugs (adjusted PR 2.29; 95% CI: 2.07-2.53) or PO only (aPR 1.72; 95%CI: 1.47-2.01). CONCLUSIONS: Changes that have occurred in the drug market are reflected in PWID's practices. The high frequency of injection observed among PO injectors is of particular concern. Drug market variations are a challenge for health authorities responsible for harm reduction programs.

HIV incidence among street youth in Montreal, Canada.

OBJECTIVES: To estimate HIV incidence and identify predictors of seroconversion among Montreal street youth. METHODS: From 1995 to 2000, street youth aged 14-25 years were recruited in a prospective cohort study. Interviews were conducted semiannually and included anti-HIV antibody testing. Among subjects who tested HIV negative at study entry and were interviewed at least twice, predictors of HIV seroconversion were identified using Cox regression. Variables considered as potential predictors were age, sex, injection drug use, being a male reporting male sexual partners, and survival sex. RESULTS: Overall, 1013 youth were recruited in the study. HIV prevalence at study entry was 1.4% [95% confidence interval (CI) 0.8-2.4] and was stable over the 6 recruitment years. Among the 863 subjects selected for the incidence analysis, 66.7% were boys, 47.2% had ever injected drugs at study entry, and 25.7% had ever engaged in survival sex. The selected participants cumulated 2327 person-years of follow-up and 16 HIV seroconversions were observed, for an incidence rate of 0.69 per 100 person-years (95% CI 0.39-1.11). In univariate analysis, injection drug use [hazard ratio (HR), 7.0] and involvement in survival sex (HR, 4.0) were associated with HIV incidence. In the multivariate analysis, only injection drug use was retained. CONCLUSIONS: Among Montreal street youth, injection drug use was the strongest predictor of HIV seroconversion. Prevention of initiation into injection drug use must become a public health priority.

Drug injection among street youth: the first time.

AIMS: To describe the circumstances of the first drug injection among street youth. DESIGN: A cohort study conducted in 1995-2000. PARTICIPANTS: Subjects aged 14-25 years old were recruited in all major Montreal organizations offering free services to street youth. MEASUREMENT: Subjects who reported having ever injected drugs completed questions on the circumstances of their first injection (calendar time, location, type of relationship with the initiator, presence of others, drug first injected, source of needle and use of clean needle and other injection materials). Questions on characteristics of the initiator and prior use of the first injected drug were added during the course of the study. FINDINGS: Of 980 participants, 530 (54%) had ever injected drugs. Questionnaires were completed by 505 subjects, including 77 who also answered the additional questions. The mean age at first injection was 17.7 years. First injection occurred mainly in public places (41%). It was performed by a close friend (41%), the youth himself/herself (27%), an acquaintance (15%), a lover (10%) or another person (7%). Overall, 84% of youth first injected with a clean needle; only 62% used clean drug preparation equipment. The first drug injected was generally cocaine (47%) or heroin (41%). Two-thirds (53/77) had used the drug of first injection previously; however, the majority was not dependent upon it. CONCLUSIONS: Most street youth used clean needles at first injection, but use of other clean injection materials was less frequent. Factors other than dependence appear to play a significant role in initiation into injection.

Seroprevalence and risk factors for hepatitis A among Montreal street youth.

OBJECTIVE: To estimate the prevalence of hepatitis A virus (HAV) antibodies among Montreal street youth. METHOD: Anti-HAV antibody testing was performed on blood samples from a hepatitis B and C study conducted among street youth in 1995-96. RESULTS: Among the 427 youth aged 14 to 25 years, prevalence of HAV antibodies was 4.7% (95% confidence interval [CI]: 2.9%-7.2%). A multivariate logistic regression analysis showed that birth in a country with a high anti-HAV prevalence (Adjusted odds ratio [AOR]: 200.7; 95% CI: 38.1-1058.4), having had sexual partner(s) with history of unspecified hepatitis (AOR: 13.8; 95% CI: 4.2-45.2), and insertive anal penetration (AOR: 5.1; 95% CI: 1.6-16.7) were independently associated with infection. CONCLUSION: Based on the relatively low HAV prevalence, the high prevalence of risk factors for infection, and the substantial hepatitis B and C prevalence, vaccination against hepatitis A is now actively promoted among Montreal street youth.

Mortality in a cohort of street youth in Montreal.

CONTEXT: Many studies have shown a high prevalence of sexually transmitted diseases, human immunodeficiency virus (HIV) infection, viral hepatitis, drug dependence, and mental health problems among street youth. However, data on mortality among these youth are sparse. OBJECTIVES: To estimate mortality rate among street youth in Montreal and to identify causes of death and factors increasing the risk of death. DESIGN, SETTING, AND POPULATION: From January 1995 to September 2000, 1013 street youth 14 to 25 years of age were recruited in a prospective cohort with semi-annual follow-ups. Original study objectives were to determine the incidence and risk factors for HIV infection in that population; however, several participants died during the first months of follow-up, prompting investigators to add mortality to the study objectives. Mortality data were obtained from the coroner's office and the Institut de la Statistique du Québec. MAIN OUTCOME MEASURES: Mortality rate among participants and factors increasing the risk of death. RESULTS: Twenty-six youth died during follow-up for a mortality rate of 921 per 100 000 person-years (95% confidence interval [CI], 602-1350); this represented a standardized mortality ratio of 11.4. The observed causes of death were as follows: suicide (13), overdose (8), unintentional injury (2), fulminant hepatitis A (1), heart disease (1); 1 was unidentified. In multivariate Cox regression analyses, HIV infection (adjusted hazard ratio [AHR] = 5.6; 95% CI, 1.9-16.8), daily alcohol use in the last month (AHR = 3.2; 95% CI, 1.3-7.7), homelessness in the last 6 months (AHR = 3.0; 95% CI, 1.1-7.6), drug injection in the last 6 months (AHR = 2.7; 95% CI, 1.2-6.2), and male sex (AHR = 2.6; 95% CI, 0.9-7.7) were identified as independent predictors of mortality. CONCLUSIONS: Current heavy substance use and homelessness were factors associated with death among street youth. HIV infection was also identified as an important predictor of mortality; however, its role remains to be clarified. These findings should be taken into account when developing interventions to prevent mortality among street youth.

Accuracy of physician reporting in routine public health surveillance for hepatitis C virus infection.

OBJECTIVE: From January 2007 to December 2008, the Montréal Public Health Department sent postal questionnaires to physicians and conducted patient interviews for all those newly diagnosed with hepatitis C virus (HCV) infection. We evaluated physician responses to risk factor questions for non-acute HCV cases. METHODS: We compared physician and patient responses with each of nine risk factor questions, determined the sensitivity and specificity of physician responses compared with patient responses, and evaluated agreement using Gwet's agreement coefficient (AC1). We ranked risk factors and compared the distributions by principal exposure category according to physician reporting vs. patient interview using the Chi-square test. RESULTS: The completeness of physicians' responses (yes, no, or unknown) varied by risk factor question from 90.8% to 96.7%. For risk factors present among more than 5% of cases, sensitivity of physician responses ranged from 26.9% to 87.7% and specificity ranged from 93.0% to 98.6%. The AC1 coefficients for agreement between physician and patient responses to lifetime risk factors considered most important in HCV acquisition were 0.80 for injection drug use, 0.95 for blood transfusion before 1990, and 0.86 for birth in a country with high HCV prevalence. Risk distributions by principal exposure category according to physician reporting vs. patient interview were not statistically different (χ(2)[4] = 2.17, p=0.704). CONCLUSION: Postal questionnaires completed by physicians appear valid for determining the principal exposure category among non-acute HCV cases. Physician reporting can be a useful and low-cost component of routine HCV surveillance.

Estimating the size of the population of persons who inject drugs in the island of Montréal, Canada, using a six-source capture-recapture model.

BACKGROUND: To plan and implement services to persons who inject drugs (PWID), knowing their number is essential. For the island of Montréal, Canada, the only estimate, of 11,700 PWID, was obtained in 1996 through a capture-recapture method. Thirteen years later, this study was undertaken to produce a new estimate. METHODS: PWID were defined as individuals aged 14-65 years, having injected recently and living on the island of Montréal. The study period was 07/01/2009 to 06/30/2010. An estimate was produced using a six-source capture-recapture log-linear regression method. The data sources were two epidemiological studies and four drug dependence treatment centres. Model selection was conducted in two steps, the first focusing on interactions between sources and the second, on age group and gender as covariates and as modulators of interactions. RESULTS: A total of 1480 PWID were identified in the six capture sources. They corresponded to 1132 different individuals. Based on the best-fitting model, which included age group and sex as covariates and six two-source interactions (some modulated by age), the estimated population was 3910 PWID (95% confidence intervals (CI): 3180-4900) which represents a prevalence of 2.8 (95% CI: 2.3-3.5) PWID per 1000 persons aged 14-65 years. CONCLUSIONS: The 2009-2010 estimate represents a two-third reduction compared to the one for 1996. The multisource capture-recapture method is useful to produce estimates of the size of the PWID population. It is of particular interest when conducted at regular intervals thus allowing for close monitoring of the injection phenomenon.

Prevalence and temporal trends of crack injection among injection drug users in eastern central Canada.

BACKGROUND: Little is known about crack injection and its temporal trends in North America. This article describes the extent of crack injection and examines temporal trends among injection drug users (IDUs) recruited from 2003 to 2010 in the SurvUDI network. METHODS: IDUs who injected recently (past 6 months) were recruited in harm reduction and health programs in eastern central Canada. Trend analyses were performed using generalized estimating equations. Some IDUs participated multiple times; first interview was retained for the descriptive analyses, while first interview per year was retained for the trend analyses. RESULTS: Of the 4088 IDUs recruited, 15.2% (621) reported crack injection; large variations across sites were noted (range: 0.3-39.5%). Trend analyses were limited to Ottawa (449 crack injectors) and Montréal (121). For Ottawa, a significant decline was observed, from 48.3% to 36.9%, with a prevalence ratio (PR) of 0.97 per year (95% CI: 0.94-0.99). For Montréal, a significant rise was observed, from 6.0% to 18.4%, with a PR of 1.29 per year (95% CI: 1.19-1.40). CONCLUSIONS: Strong variations in crack injection exist throughout the SurvUDI network, and reversed temporal trends have been observed in Ottawa and Montréal. These data will be useful to local harm reduction programs to evaluate the need to distribute items required by crack injectors and to develop prevention messages.

Injection of drug residue as a potential risk factor for HCV acquisition among Montréal young injection drug users.

BACKGROUND: Preparing drugs or medications for injection may leave residues in containers and filters used by injection drug users (IDUs). Little is known about the specific practice of injecting someone else's drug residue as a possible route of HCV transmission. METHODS: A prospective cohort study of street youth aged 14-23 years old was carried out between July 2001 and December 2005. For this analysis, youth who injected in the six months prior to interview were selected if they were HCV-negative and had completed at least one follow-up visit. Semi-annual visits involved completing an interviewer-administered questionnaire and providing a blood sample for HCV antibody testing. "Sharing behaviors" (any injection preparation behavior that could entail IDUs using injection equipment used by others) including injecting someone else's drug residue were assessed at each interview. Predictors of HCV seroconversion were identified using Cox proportional hazards regression analyses. Two multivariate models were built, one considering sharing behaviors only, and one with cocaine injection forced into it. RESULTS: Of the 175 participants, 60% were male and their mean age was 20.7years old. In both models, residue injection was a predictor of HCV incidence, although with marginal statistical significance. The adjusted hazard ratio estimates were (2.15; 95% CI 0.99-4.67) and (2.11; 95% CI 0.97-4.62) respectively. CONCLUSION: This epidemiological study underscores the role injection of drug residue may play in HCV transmission among IDUs. In the current context of the worldwide HCV epidemics, this question deserves further investigation.