Periods of Homelessness Linked to Higher VACS Index Among HIV-Positive People Who Use Drugs.

We sought to evaluate the impact of homelessness on HIV disease progression among people who use unregulated drugs (PWUD) living with HIV and test if this association was mediated by adherence to antiretroviral therapy (ART). We applied general linear mixed-effects modeling to estimate the longitudinal relationship between homelessness and the Veterans Aging Cohort Study (VACS) Index, a validated measure of HIV disease progression that predicts all-cause mortality, among a prospective cohort of PWUD. In a longitudinal model adjusted for ART adherence, homelessness was significantly associated with increased VACS Index scores and 16% of the association was mediated by ART adherence. These findings indicate that homelessness was a significant risk factor for HIV disease progression and this association was marginally mediated by ART adherence. Future studies are needed to quantify the other mechanisms (e.g., food insecurity, mental health) by which homelessness increases mortality risk among PWUD living with HIV.

The Veterans Aging Cohort Study (VACS) Index Predicts Mortality in a Community-recruited Cohort of People With Human Immunodeficiency Virus (HIV) Who Use Illicit Drugs.

The Veterans Aging Cohort Study (VACS) index combines commonly collected clinical biomarkers to estimate human immunodeficiency virus (HIV) disease severity. Among a prospective cohort of people living with HIV who use illicit drugs (PWUD) (n = 948), we found that the VACS index was significantly associated with mortality over a 20-year study period.

Prevalence and longitudinal correlates of recent exposure to fentanyl among HIV-positive people who use unregulated drugs during a community-wide overdose crisis.

The United States and Canada are experiencing an opioid overdose crisis driven largely by exposure to fentanyl (a potent synthetic opioid), with little known about fentanyl exposure among HIV-positive people who use unregulated drugs (PWUD). We sought to estimate the prevalence and correlates of fentanyl exposure among a community-recruited sample derived from a prospective cohort study of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects analyses were used to identify longitudinal factors associated with a fentanyl-positive urine drug screen test. Between June 2016-November 2017, 456 participants were recruited and contributed 1007 observations. At baseline, 96% of participants were ART-exposed, 72% had an HIV viral load (VL) <50 copies/mL and 21% had a fentanyl-positive test. Longitudinally, fentanyl-positive tests were characterized by: younger participant age (Adjusted Odds Ratio [AOR] = 0.45), recent non-fatal overdose (AOR = 2.30), engagement in opioid agonist therapy (AOR = 1.91), and at least daily heroin injection (AOR = 11.27). CD4+ cell count was negatively associated with fentanyl urine positivity (AOR = 0.92) (all p < 0.05). We identified several risk factors for overdose linked to fentanyl exposure among this sample, although no link with HIV treatment engagement or detectable HIV VL. Innovative strategies are needed to reduce the harmful effects of the contaminated unregulated drug supply experienced by PWUD.

Pain and Barriers to Accessing Health Services Among People Who Use Drugs.

BACKGROUND: The opioid overdose crisis underscores the need for health services among people who use drugs (PWUD) with concurrent pain. AIMS: Investigating the effect of pain on barriers to accessing health services among PWUD. DESIGN: Prospective cohort study. SETTINGS: A setting of universal access to no-cost medical care in Vancouver, Canada from June 2014 to May 2016. PARTICIPANTS/SUBJECTS: PWUD who completed at least one study interview. METHODS: Data derived from interviewer-administered questionnaires were used for multivariable generalized linear mixed-effects multiple regression (GLMM) analyses. RESULTS: Among 1,348 PWUD, 469 (34.8%) reported barriers to accessing health services at least once during the study period. The median average pain severity was 3 (IQR: 0-6) out of 10. A dose-response relationship was observed between greater pain and increased odds of reporting barriers to accessing health services (adjusted odds ratio [AOR]: 1.59, 95% confidence interval [CI]: 1.15-2.21, p = .005 for mild versus no pain; AOR: 1.76, 95% CI: 1.30-2.37, p < .001 for moderate versus no pain; AOR: 2.55, 95% CI: 1.92-3.37, p < .001 for severe versus no pain). Common barriers included poor treatment by health professionals, socio-structural barriers such as transportation or mobility, and long wait lists or wait times. CONCLUSIONS: Pain may be a significant risk factor associated with increased barriers to accessing health services among PWUD. Attention to pain management may improve access to health services, and reducing barriers to health services may conversely improve pain management and its related risks and harms.

High-intensity cannabis use and hospitalization: a prospective cohort study of street-involved youth in Vancouver, Canada.

BACKGROUND: There is concern that cannabis use negatively affects vulnerable groups such as youth; however, the relationship between cannabis use and health care utilization has not been well characterized in this population. We longitudinally evaluated the association between daily cannabis use and hospitalization among a prospective cohort of street-involved youth. METHODS: Data were collected from the At-Risk Youth Study (ARYS) in Vancouver, Canada, from September 2005 to May 2015. Participants were interviewed semi-annually and multivariable generalized estimating equation (GEE) logistic regression was used to examine the relationship between daily cannabis use and hospitalization. RESULTS: A total of 1216 participants (31.2% female) were included in this analysis, and 373 (30.7%) individuals reported hospitalization at some point during the study period. In a multivariable GEE analysis, daily cannabis use was not significantly associated with hospitalization (Adjusted Odds Ratio [AOR] = 1.17, 95% Confidence interval [CI] = 0.84, 1.65). We did observe a significant interaction between daily cannabis use and sex (AOR = 0.51, 95% CI = 0.34, 0.77), whereby cannabis use was associated with a decreased odds of hospitalization among males (AOR = 0.60, 95% CI = 0.47, 0.78), yet was not significantly associated with hospitalization among females (AOR = 1.19, 95% CI = 0.84, 1.67). CONCLUSIONS: The finding that daily cannabis use was not associated with hospitalization among street-involved youth is encouraging given the high rates of cannabis use in this population and the expansion of cannabis legalization and regulation. Future studies, however, are warranted to monitor possible changes in the consequences of cannabis use as cannabis legalization and regulation increase internationally.

Trust in research physicians as a key dimension of randomized controlled trial participation in clinical addictions research.

Background: In the development of pharmacotherapies for substance use disorders, willingness to participate in randomized controlled trials (RCTs) among people who use drugs (PWUD) is influenced by numerous social and structural factors. Considering the criminalization and stigma experienced by PWUD and range of experiences in healthcare and research, PWUD may vary in their trust of health providers, health research physicians, or medical research processes. We therefore examine associations between trust in these three domains and willingness to participate in a hypothetical RCT for a novel pharmacotherapy for stimulant use among PWUD. Methods: Data were derived from a cross-sectional questionnaire administered to participants using crack and/or cocaine from three cohort studies of PWUD in Vancouver (N = 229). Results: A majority of participants were "definitely" or "probably" willing to participate in an RCT. In multivariable ordinal regression, trust in research physicians was positively associated with willingness to participate, while trust in primary care providers or medical research processes were not significantly associated. Conclusions: This data suggests trust in research physicians plays a role in RCT decision-making among PWUD, while trust in healthcare providers and research processes appears less relevant. These findings highlight opportunities for supporting RCT recruitment by building trust in research physicians.

Inability to access primary care clinics among people who inject drugs in a Canadian health care setting.

OBJECTIVE: To examine the prevalence and correlation of self-reported inability to access community primary care clinics among people who inject drugs (PWID). DESIGN: Self-report questionnaire data. SETTING: Vancouver, BC. PARTICIPANTS: Data were derived from 3 prospective cohort studies of PWID between 2013 and 2016. MAIN OUTCOME MEASURES: Multivariable generalized estimating equations were used to determine prevalence of and reasons for self-reported inability to access primary care, as well as factors associated with inability to access care. RESULTS: Of 1396 eligible participants, including 525 (37.6%) women, 209 (15.0%) persons were unable to access a primary care clinic at some point during the study period. In the multivariable analysis, factors independently associated with inability to access clinics included ever being diagnosed with a mental health disorder (adjusted odds ratio [AOR] = 1.63, 95% CI 1.14 to 2.35), dealing drugs (AOR = 1.60, 95% CI 1.15 to 2.22), using emergency services (AOR = 1.51, 95% CI 1.13 to 2.02), being female (AOR = 1.49, 95% CI 1.08 to 2.08), and testing positive for HIV (AOR = 0.47, 95% CI 0.30 to 0.72) (for all factors, P < .05). CONCLUSION: Specific exposures were linked to challenges in accessing primary care among the sample of PWID, even in a publicly funded health care setting. Notably, models designed for care of people with HIV appear to increase access to primary care among PWID. Further research is needed to determine how to effectively treat accompanying mental illness, how to provide women-centred services, and how to connect people with primary care who would likely otherwise go to the emergency department.

Effect of witnessing an overdose on the use of drug checking services among people who use illicit drugs in Vancouver, Canada.

BACKGROUND: Since 2013, fentanyl-contaminated drugs have been driving North America's opioid-overdose epidemic. Drug checking, which enables people who use illicit drugs (PWUD) to test and receive feedback regarding the contents of their drugs, is being considered as a potential tool to address the toxic drug supply. While some PWUD witness overdoses, little is known about the impact of these experiences on subsequent risk reduction practices. OBJECTIVE: The purpose of this study was to examine the effect of witnessing an overdose on drug checking service use. METHODS: Data were derived from prospective cohorts of PWUD in Vancouver, Canada, a setting with a community-wide fentanyl overdose crisis, between June 1, 2018 and December 1, 2018. Multivariable logistic regression was used to estimate the effect of witnessing an overdose on drug checking service use. RESULTS: 1,426 participants were eligible for the study, including 530 females; 767 (53.8%) participants reported witnessing an overdose and 196 (13.7%) reported using drug checking services in the last 6 months. In multivariable analyses, after adjusting for a range of confounders including the use of fentanyl, witnessing an overdose was positively associated with drug checking service use (adjusted odds ratio = 2.32; 95% confidence interval: 1.57-3.49). CONCLUSION: Our findings suggest that witnessing an overdose may motivate PWUD to use drug checking services. Given that only a small proportion of PWUD in the study reported using drug checking services, our findings highlight the need to continue to scale-up a range of overdose prevention interventions.

Overdose Risk and Acquiring Opioids for Nonmedical Use Exclusively from Physicians in Vancouver, Canada.

BACKGROUND: A primary response to the alarming rise in overdose and mortality due to nonmedical prescription opioid (PO) use has been to restrict opioid prescribing; however, little is known about the relationship between obtaining opioids from a physician and overdose risk among people who use POs nonmedically and illicit street drugs. Objectives: Investigate the relationship between non-fatal overdose and acquiring POs exclusively from physicians for the purposes of engaging in nonmedical PO use. Methods: Data were collected between 2013 and 2016 among participants in two harmonized prospective cohort studies of people who use drugs in Vancouver: the At-Risk Youth Study (ARYS) and the Vancouver Injection Drug Users Study (VIDUS). Analyses were restricted to participants who engaged in nonmedical PO use and used generalized estimating equations. Results: Among 599 participants who used POs nonmedically, 82 (14%) individuals reported acquiring POs exclusively from a physician and 197 (33%) experienced a non-fatal overdose at some point over the study period. Acquiring POs exclusively from physicians was significantly and negatively associated with non-fatal overdose in the bivariate analysis (Odds Ratio = 0.60, 95% Confidence Interval (CI): 0.39-0.94) but not the final multivariate analysis (Adjusted Odds Ratio =0.87, 95% CI: 0.53-1.44). Conclusions: Compared to individuals who acquired POs from friends or the streets, participants who acquired POs exclusively from a physician were not at an increased risk of non-fatal overdose. Although responsible opioid prescribing is an important priority, additional strategies to address nonmedical PO use are urgently needed to reduce overdose and related morbidity and mortality.

Temporal changes in non-fatal opioid overdose patterns among people who use drugs in a Canadian setting.

Background and Aims: Little is known about how the expansion of opioid agonist therapy (OAT) and emergence of fentanyl in the illicit drug supply in North America has influenced non-fatal opioid overdose (NFOD) risk. Therefore, we sought to identify patterns of substance use and addiction treatment engagement (i.e., OAT, other inpatient or outpatient treatment) prior to NFOD, as well as the trends and correlates of each pattern among people who use drugs (PWUD) in Vancouver, Canada. Methods: Data were derived from participants in three prospective cohorts of PWUD in Vancouver in 2009-2016. Observations from participants reporting opioid-related NFOD in the previous six months were included. A latent class analysis was used to identify classes based on substances used at the time of last NFOD and addiction treatment engagement in the month prior to the last NFOD. Multivariable generalized estimating equations estimated the correlates of each class membership. Results: In total, 889 observations from 570 participants were included. Four distinct classes were identified: (1) polysubstance use (PSU) and addiction treatment engagement; (2) PSU without treatment engagement; (3) exposure to unknown substances, mostly without treatment engagement; and (4) primary heroin users without treatment engagement. The class of exposure to unknown substances appeared in 2015 and became the dominant group (76.9%) in 2016. In multivariable analyses, the odds of membership in the class of primary heroin users decreased over time (adjusted odds ratio [AOR]: 0.74, 95% confidence interval [CI]: 0.68-0.81). Conclusions: Changing profiles of PWUD reporting opioid-related NFOD were seen over time. Notably, there was a sudden increase in reports of overdose following exposure to unknown substances since 2015, the majority of whom reported no recent addiction treatment engagement. Further study into patterns of substance use and strategies to improve addiction treatment engagement is needed to improve and focus overdose prevention efforts.

Disparities in uptake of direct-acting antiviral therapy for hepatitis C among people who inject drugs in a Canadian setting.

BACKGROUND & AIMS: Despite the high burden of hepatitis C virus (HCV) infection among people who inject drugs (PWID), uptake of interferon-based therapies has been extremely low. Increasing availability of direct-acting antiviral (DAA)-based therapies offers the possibility of rapid treatment expansion with the goal of controlling the HCV epidemic. We evaluated DAA-based treatment uptake among HCV-positive PWID in Vancouver after introduction of DAAs in the government drug formulary. METHODS: Using data from three cohorts of PWID in Vancouver, Canada, we investigated factors associated with DAA-therapies uptake among participants with HCV between April 2015 and November 2017. RESULTS: Of the 915 HCV-positive PWID, 611 (66.8%) were recent PWID and 369 (40.3%) had HIV coinfection. During the study period, 146 (16.0%) initiated DAA-therapies, a rate of 6.0 per 100 person-year, with higher initiation rates among non-recent PWID and an increasing trend over time. In multivariable analysis, HIV coinfection (Adjusted Odds Ratio [AOR] = 2.29, 95% Confidence Interval [CI]: 1.55-3.40), white race (AOR = 1.56, 95% CI: 1.05-2.35), and engagement in HCV care (AOR = 1.94, 95% CI: 1.31-2.90) were positively associated with DAA-therapies uptake, while high-risk drinking (AOR = 0.47, 95% CI: 0.23-0.88) and daily crack use were negatively associated (AOR = 0.41, 95% CI: 0.17-0.85). Among recent PWID, engagement in opioid agonist therapy emerged as an independent correlate of DAA uptake. CONCLUSIONS: Despite increases in HCV treatment uptake among PWID after the introduction of DAAs in our setting, disparities in access remain. Social-structural and behavioural barriers to HCV care should be addressed for the success of any HCV elimination strategy.

Characterizing Men Who Have Sex with Men and Use Injection Drugs in Vancouver, Canada.

We examined factors associated with reporting sex with men among men who inject drugs in Vancouver, Canada. Data were drawn from three open prospective cohorts of people who use drugs between 2005 and 2014. Generalized estimating equations were used to identify factors associated with reporting non-transactional sex with men (MSM) in the previous 6 months. Of 1663 men who used injection drugs, 225 (13.5%) were MSM over the study period. Sex with men was independently associated with younger age [Adjusted Odds Ratio (AOR) = 0.96], childhood sexual abuse (AOR = 2.65), sex work (AOR = 3.33), crystal methamphetamine use (AOR = 1.30), borrowing used syringes (AOR = 1.39), inconsistent condom use (AOR = 1.76), and HIV seropositivity (AOR = 3.82). MSM were less likely to be Hepatitis C-positive (AOR = 0.43) and to have accessed addiction treatment in the previous 6 months (AOR = 0.83) (all p < 0.05). Findings highlight vulnerabilities and resiliencies among MSM-PWID and indicate a need for trauma-informed and affirming harm reduction and substance use treatment services for MSM-PWID.

Food insufficiency is associated with depression among street-involved youth in a Canadian setting.

OBJECTIVE: Food insufficiency, defined by the experience of hunger, is known to be prevalent and a source of health-related harm among-street involved youth, but little is known about its relationship with depression in this population. Therefore, we sought to assess the association between food insufficiency and symptoms of depression among a cohort of street-involved youth. DESIGN: Multivariable logistic regression was used to assess the relationship between food insufficiency, defined as being hungry but not having enough money to buy food, and depression as measured by the Center for Epidemiological Studies Depression (CES-D) scale. SETTING: Data from April 2006 to November 2013 were derived from the At-Risk Youth Study (ARYS), a prospective cohort of street-involved youth who use illicit drugs in Vancouver, Canada. SUBJECTS: There were 1066 street-involved youth enrolled in the study, including 340 (31·9 %) females. RESULTS: Of 1066 youth enrolled in the study, 724 (67·9 %) reported some food insufficiency and 565 (53·0 %) met criteria for depression. Compared with youth who did not report food insufficiency, those who reported often experiencing food insufficiency had a higher likelihood of reporting depression (adjusted OR=2·52; 95 % CI 1·74, 3·67), as did those who reported sometimes experiencing food insufficiency (adjusted OR=1·99; 95 % CI 1·47, 2·70). CONCLUSIONS: Food insufficiency was prevalent and associated in a dose-dependent trend with symptoms of depression among street-involved youth in our setting. Findings highlight the need to address the nutritional and mental health needs of youth and identify pathways by which food insufficiency may contribute to depression among vulnerable populations.

Residential eviction predicts initiation of or relapse into crystal methamphetamine use among people who inject drugs: a prospective cohort study.

Reports of increasing methamphetamine use among vulnerable populations may be attributed in part to the adaptive use of stimulants in response to the loss of stable housing through residential eviction. We employed multivariable recurrent event extended Cox regression to examine the independent association between recent evictions and initiation of or relapse into crystal methamphetamine use among people who inject drugs in Vancouver, Canada enrolled in two prospective cohort studies. In a multivariable analysis, eviction remained independently associated with methamphetamine initiation or relapse (adjusted hazard ratio = 1.90; 95% confidence interval: 1.31-2.75). Findings demonstrate the need to secure tenancies for drug-using populations to reduce harms.

High Prevalence of Self-Reported Exposure to Adulterated Drugs Among People Who Experienced an Opioid Overdose in Canada: A Cohort Study.

BACKGROUND: In North America, rates of overdoses are increasing largely due to the adulteration of illicit drugs by illicit synthetic opioids. OBJECTIVES: We sought to examine the prevalence and correlates of self-reported exposure to adulterated drugs among people who experienced a non-fatal opioid overdose. METHODS: Data were derived from three prospective cohort studies of people who use drugs in Vancouver, Canada between June and November 2016. Multivariable logistic regression analyses were used to examine the prevalence and correlates of self-reported exposure to adulterated drugs. RESULTS: Among 117 participants who reported symptoms consistent with a non-fatal opioid overdose, 78 (66.7%) reported believing the drug was adulterated during their last overdose. Of those, 42 (53.8%) had not perceived adulteration prior to overdose. In the multivariable analysis, engagement in opioid agonist therapy (Adjusted Odds Ratio [AOR] = 2.79, 95% Confidence Interval [CI]: 1.10, 7.45) was independently associated with having not perceived adulteration prior to overdose. Daily heroin use (AOR = 5.28; 95% CI: 1.92, 15.97) and reporting supervised injection site staff were present at most recent overdose (AOR = 6.16; 95% CI: 1.25, 47.27) were independently associated with having perceived adulteration prior to overdose. Conclusions/Importance: We found a high prevalence of believing adulterated drugs were present for the most recent overdose. Further, the high prevalence of unperceived adulteration prior to overdose supports the need to lower the risk of overdose by providing individuals with options to consume drugs in a safer manner, including supervised consumption sites.

Perceived Devaluation among a Cohort of Street-Involved Youth in Vancouver, Canada.

BACKGROUND: Perceived devaluation is a barrier to seeking mental and physical health services among people who use illicit drugs. OBJECTIVE: Assessing the prevalence and correlates of perceived devaluation within a cohort of street-involved youth. METHODS: Data were drawn from an open prospective cohort of street-involved youth who use illicit drugs (aged 14-26 at study enrollment) between December 2013 and May 2015 in Vancouver, Canada. Perceived devaluation was measured using an adapted version of Perceived Devaluation and Discrimination scale. Multivariable generalized estimating equations were constructed to examine factors independently associated with high perceived devaluation. RESULTS: Among 411 street-involved youth, 95.1% reported high perceived devaluation at some point during the study period. In a multivariable analysis, youth who reported high perceived devaluation were significantly more likely to engage in: unprotected sex (Adjusted Odds Ratio [AOR] = 1.56, 95% Confidence Interval 1.03-2.37); heavy alcohol use (AOR = 2.31, 95% CI 1.22-4.36); and daily heroin use (AOR = 2.07, 95% CI 1.16-3.70). Youth who resided in the Downtown Eastside neighborhood were significantly less likely to report high perceived devaluation (AOR = 0.41, 95% CI 0.26-0.65). CONCLUSIONS: Perceived devaluation was extremely prevalent among street-involved youth in our sample. We also observed that youth most in need of health and social services were significantly more likely to report high levels of perceived devaluation which may result in a reluctance to seek out key services and supports. These findings highlight the need to implement stigma reduction interventions for vulnerable youth in this setting.

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) use and transitions to injection drug use among street-involved youth.

Background: Despite the popularity of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) among young people across North America and Europe, MDMA is rarely explored in studies of young people at high risk of injecting drugs. We conducted a study among street-involved youth who use illicit drugs in Vancouver, Canada, to understand if use of MDMA is associated with initiation of injection drugs. Methods: We followed injection-naïve participants in the At-Risk Youth Study (ARYS), an ongoing prospective cohort of street-involved youth aged 14-26 who use illicit drugs. Bivariate and multivariate extended Cox models with time-updated variables were used to examine the association between MDMA use and initiation of injection drug use between September 2005 and May 2015. Results: Among 483 youth, 306 (63.4%) had a history of MDMA use and 218 (45.1%) had used MDMA in the previous 6 months at baseline. A total of 105 (21.7%) youth initiated injection drug use over the 10-year period, yielding an incidence density of 8.51 (95% confidence interval [CI]: 6.96-10.30) per 100 person-years. MDMA use was not significantly associated with initiating injection drugs at the bivariate (hazard ratio: 0.93, 95% CI: 0.61-1.42) or multivariate (adjusted hazard ratio: 0.88, 95% CI: 0.57-1.35) level, after adjusting for socio-demographic and substance use confounders. Conclusions: Amid ongoing frequent use of MDMA among some young people in North America, we did not observe an elevated risk of injection initiation among those who used MDMA in this cohort of street-involved youth.

HIV Incidence Among Men Who Have Sex with Men and Inject Drugs in a Canadian Setting.

Few data on HIV incidence among men who have sex with men and inject drugs (MSM-PWID) are available. Drawing on a prospective cohort in Vancouver, Canada, we examined the relationship between MSM status and HIV incidence among PWID using Kaplan-Meier analyses and extended Cox regression. Data were collected from 1996 to 2014 and analyzed in 2017. Of 1131 HIV-negative male PWID, 8.6% (n = 97) reported sex with men over the study period. MSM status was crudely associated with HIV incidence [Hazard Ratio (HR) = 1.81; 95% CI 1.08-3.03], but not after adjustment for daily cocaine injection and syringe borrowing (Adjusted HR = 1.33; 95% CI 0.78-2.28). Findings highlight the need for harm reduction interventions and socio-behavioral research focused on MSM-PWID.

Patterns of Non-injection Drug Use Associated with Injection Cessation among Street-Involved Youth in Vancouver, Canada.

Although abstinence from drug use is often a key goal of youth substance use treatment, transitioning to less harmful routes and types of drug use is desirable from both a clinical and public health perspective. Despite this, little is known about the trajectories of youth who inject drugs including changes in patterns of non-injection drug use. The At-Risk Youth Study (ARYS) is a longitudinal cohort of street-involved youth who use drugs in Vancouver, Canada. We used linear growth curve modeling to compare changes in non-injection drug use among participants who ceased injecting drugs for at least one 6-month period between September 2005 and May 2015 to matched controls who continued injecting over the same period. Of 387 eligible participants, 173 (44.7%) reported ceasing drug injection at least once. Non-injection drug use occurred during 160 (79.6%) periods of injection cessation. In adjusted linear growth curve analyses, the only non-injection drug use pattern observed to decrease significantly more than controls following injection cessation was daily crack/cocaine use (p = 0.024). With the exception of frequent crack/cocaine use, transitions out of injection drug use did not appear to coincide with increased reductions in patterns of non-injection drug use. Our findings indicate that most (80%) of the observed injection cessation events occurred in the context of ongoing substance use. Given that transitioning out of drug injection represents a significant reduction in risk and harm, efforts supporting vulnerable youth to move away from injecting may benefit from approaches that allow for ongoing non-injection drug use.

Hospitalization among street-involved youth who use illicit drugs in Vancouver, Canada: a longitudinal analysis.

BACKGROUND: Street-involved youth who use illicit drugs are at high risk for health-related harms; however, the profile of youth at greatest risk of hospitalization has not been well described. We sought to characterize hospitalization among street-involved youth who use illicit drugs and identify the most frequent medical reasons for hospitalization among this population. METHODS: From January 2005 to May 2016, data were collected from the At-Risk Youth Study (ARYS), a prospective cohort study of street-involved youth in Vancouver, Canada. Multivariable generalized estimating equation (GEE) was used to identify factors associated with hospitalization. RESULTS: Among 1216 participants, 373 (30.7%) individuals reported hospitalization in the previous 6 months at some point during the study period. The top three reported medical reasons for hospital admission were the following: mental illness (37.77%), physical trauma (12.77%), and drug-related issues (12.59%). Factors significantly associated with hospitalization were the following: past diagnosis of a mental illness (adjusted odds ratio [AOR] = 1.85; 95% confidence interval [95% CI] 1.47-2.33), frequent cocaine use (AOR = 2.15; 95% CI 1.37-3.37), non-fatal overdose (AOR = 1.76; 95% CI 1.37-2.25), and homelessness (AOR = 1.40; 95% CI 1.16-1.68) (all p < 0.05). CONCLUSIONS: Findings suggest that mental illness is a key driver of hospitalization among our sample. Comprehensive approaches to mental health and substance use in addition to stable housing offer promising opportunities to decrease hospitalization among this vulnerable population.