Cari L. Miller

Factors associated with premature mortality among young injection drug users in Vancouver

BackgroundYoung injection drug users (IDUs) may be at increased risk of premature mortality due to the health risks associated with injection drug use including overdoses and infections. However, there has been little research conducted on mortality causes, rates and associations among this population. We undertook this study to investigate patterns of premature mortality, prior to age 30 years, among young IDUs.MethodsSince 1996, 572 young (≤29 years) IDUs have been enrolled in the Vancouver Injection Drug Users Study (VIDUS). Semi-annually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and hepatitis C (HCV). Mortality data have been continually updated through linkages with the Provincial Coroners Office. Crude and age-specific mortality rates, standardized mortality ratios, and life expectancy measures were calculated using person-time methods. Predictors of mortality were identified using Cox regression analyses.FindingsTwenty-two participants died prior to age 30 years during the follow-up period for an overall crude mortality rate of 1,368 per 100,000 person-years. Overall, young IDUs were 16.4 times (95% confidence interval [CI]; 9.1–27.1) more likely to die; young women IDUs were 54.1 times (95%CI; 29.6–90.8) and young men IDUs were 12.9 times (95%CI; 5.5, 25.3) more likely to die when compared to the Canadian non-IDU population of the same age. The leading observed cause of death among females was: homicide (N = 9); and among males: suicide (N = 3) and overdose (N = 3). In Cox regression analyses, factors associated with mortality were, HIV infection (Hazard Ratio [HR]: 4.55; CI: 1.92–10.80) and sex work (HR: 2.76; CI: 1.16–6.56).InterpretationPremature mortality was 13 and 54 times higher among young men and women who use injection drugs in Vancouver than among the general population in Canada. The majority of deaths among the women were attributable to homicide, suggesting that interventions should occur not only through harm reduction services but also through structural interventions at the legal and policy level.

Food Insecurity and Sexual Risk in an HIV Endemic Community in Uganda

Food insecurity has been linked to high-risk sexual behavior in sub-Saharan Africa, but there are limited data on these links among people living with HIV/AIDS, and on the mechanisms for how food insecurity predisposes individuals to risky sexual practices. We undertook a series of in-depth open-ended interviews with 41 individuals living with HIV/AIDS to understand the impact of food insecurity on sexual-risk behaviors. Participants were recruited from the Immune Suppression Clinic at the Mbarara University of Science and Technology in Mbarara, Uganda. Interviews were recorded, transcribed verbatim, translated, and coded following the strategy of grounded theory. Four major themes emerged from the interview data: the relationship between food insecurity and transactional sex for women; the impact of a husband’s death from HIV on worsening food insecurity among women and children; the impact of food insecurity on control over condom use, and the relationship between food insecurity and staying in violent/abusive relationships. Food insecurity led to increased sexual vulnerability among women. Women were often compelled to engage in transactional sex or remain in violent or abusive relationships due to their reliance on men in their communities to provide food for themselves and their children. There is an urgent need to prioritize food security programs for women living with HIV/AIDS and address broader gender-based inequities that are propelling women to engage in risky sexual behaviors based on hunger. Such interventions will play an important role in improving the health and well-being of people living with HIV/AIDS, and preventing HIV transmission.

Surviving the sex trade: a comparison of HIV risk behaviours among street-involved women in two Canadian cities who inject drugs.

In Canada, very little is known about the factors and processes that cause drug-related harm among female intravenous drug users (IDUs). Women who inject drugs and participate in the survival sex trade are considered to be at increased risk for sexual and drug-related harms, including HIV infection. Between September 1999 and September 2000, women participating in the VIDUS cohort in Vancouver and the St. Luc Cohort in Montreal completed interviewer-administered questionnaires. Analyses were conducted to compare the demographic characteristics, sexual risk behaviours, risky injection practices and drug use patterns among women who self-identified as participating in the sex trade with those who did not identify as participating in the sex trade. Logistic regression was used to identify factors independently associated with exchanging sex for money or drugs. HIV prevalence at the study visit (September 1999-2000) was 29% for sex trade workers and 29.2% for non-sex trade workers. While patterns of sexual risk were similar, the risky injection practice and drug use patterns between sex trade workers and non-sex trade workers were markedly different. Logistic regression analysis of cross-sectional data revealed that independent behaviours associated with the sex trade included: greater than once per day use of heroin (adjusted OR 2.7), smokeable crack cocaine (adjusted OR=3.3) and borrowing used syringes (adjusted OR=2.0). Creative, client-driven interventions are urgently needed for women who trade sex for money or for drugs.

Women and Vulnerability to HAART Non-Adherence: A Literature Review of Treatment Adherence by Gender from 2000 to 2011

A literature review of original research articles on adherence to antiretroviral therapy (ART) in developed countries, covering January 2000 to June 2011, was conducted to determine if gender differences exist in the prevalence of nonadherence to ART. Of the 1,255 articles reviewed, only 189 included data on the proportion of the study population that was adherent and only 57 (30.2%) of these reported proportional adherence values by gender. While comparing articles was challenging because of varied reporting strategies, women generally exhibit poorer adherence than men. Thirty of the 44 articles (68.2%) that reported comparative data on adherence by gender found women to be less adherent than men. Ten articles (17.5%) reported significant differences in proportional adherence by gender, nine of which showed women to be less adherent than men. These findings suggest that in multiple studies from developed countries, female gender often predicts lower adherence. The unique circumstances of HIV–positive women require specialized care to increase adherence to ART.

The future face of coinfection: prevalence and incidence of HIV and hepatitis C virus coinfection among young injection drug users.

The purpose of this study was to determine the prevalence and incidence of HIV and hepatitis C virus (HCV) coinfection among young (aged 29 years or younger) injection drug users (IDUs) and to compare sociodemographic and risk characteristics between (HIV/HCV) coinfected, monoinfected, or HIV- and HCV-negative youth. Data were collected through the Vancouver Injection Drug Users Study (VIDUS). To date, more than 1400 IDUs have been enrolled and followed, of whom 479 were aged 29 years or younger. Semiannually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and HCV. Univariate and multivariate logistic regression analyses were undertaken to investigate predictors of baseline coinfection. Cox regression models with time-dependent covariates were used to identify predictors of time to secondary infection seroconversion. A Cochran-Armitage trend test was used to determine risk associations across 3 categories: no infection, monoinfection, and coinfection. Of the 479 young injectors, 78 (16%) were coinfected with HIV and HCV at baseline and a further 45 (15%) with follow-up data became coinfected during the study period. Baseline coinfection was independently associated with being female, being aboriginal, older age, greater number of years injecting, and living in the IDU epicenter. Factors independently associated with time to secondary infection seroconversion were borrowing needles and greater than once-daily cocaine injection, and accessing methadone maintenance therapy in the previous 6 months was protective. There were clear trends across the 3 categories for increasing proportions of female subjects, aboriginal subjects, older age, greater number of years injecting, living in the IDU epicenter, and daily cocaine use. There were a shocking number of youth living with coinfection, particularly female and aboriginal youth. The median number of years injecting for youth seroconverting to a secondary infection was 3 years, suggesting that appropriate public health interventions should be implemented immediately.

Injection drug use among street-involved youth in a Canadian setting

BackgroundStreet-involved youth contend with an array of health and social challenges, including elevated rates of blood-borne infections and mortality. In addition, there has been growing concern regarding high-risk drug use among street-involved youth, in particular injection drug use. We undertook this study to examine the prevalence of injection drug use and associated risks among street-involved youth in Vancouver, Canada.MethodsFrom September 2005 to November 2007, baseline data were collected for the At-Risk Youth Study (ARYS), a prospective cohort of street-recruited youth aged 14 to 26 in Vancouver, Canada. Using multiple logistic regression, we compared youth with and without a history of injection.ResultsThe sample included 560 youth among whom the median age was 21.9 years, 179 (32%) were female, and 230 (41.1%) reported prior injection drug use. Factors associated with injection drug use in multivariate analyses included age ≥ 22 years (adjusted odds ratio [AOR] = 1.18, 95% CI: 1.10–1.28); sex work involvement (AOR = 2.17, 95% CI: 1.35–3.50); non-fatal overdose (AOR = 2.10, 95% CI: 1.38–3.20); and hepatitis C (HCV) infection (AOR = 22.61, 95% CI: 7.78–65.70).ConclusionThese findings highlight an alarmingly high prevalence of injection drug use among street-involved youth and demonstrate its association with an array of risks and harms, including sex work involvement, overdose, and HCV infection. These findings point to the need for a broad set of policies and interventions to prevent the initiation of injection drug use and address the risks faced by street-involved youth who are actively injecting.

Binge Drug Use Independently Predicts HIV Seroconversion Among Injection Drug Users: Implications for Public Health Strategies

Several studies have highlighted risk factors that cause HIV vulnerability among injection drug users (IDUs); these studies in turn have prompted public health officials to take action to minimize these risks. We sought to evaluate the potential association between binge drug use and HIV seroconversion and, subsequently, risk factors associated with binge drug use among a cohort of IDUs. To do this, we performed analyses of (1) associations with HIV seroconversion and (2) associations with binge drug use among participants enrolled in the Vancouver Injection Drug Users Study (VIDUS), a prospective cohort of IDU. Because serial measures for each individual were available, we undertook a time-updated Cox regression analysis to detect associations with HIV incidence and variables potentially associated with binge drug use were evaluated by using generalized estimating equations (GEE). Overall, 1548 IDU were enrolled into the VIDUS cohort between May 1996 and May 2003. There were 1013 individuals who were HIV seronegative at enrollment and had at least one follow-up visit; 125 (12%) became HIV positive during the study period for a cumulative incidence rate of 14% at 64 months after enrollment. In the final multivariate model, binge drug use [Adjusted Hazards Ratio: 1.61 (CI: 1.12, 2.31)] was independently associated with HIV seroconversion. In subanalyses, when we evaluated associations with binge drug use in GEE analyses, borrowing [Odds Ratio (OR): 153 (CI: 1.33–1.76)] and lending [OR: 1.73 (CI: 1.50–1.98)] syringes, sex trade work [OR: 1.14 (CI: 1.01–1.29)], frequent cocaine [OR: 2.34 (CI: 2.11–2.60)] and heroin [OR: 1.29 (CI: 1.17–1.43)] injection were independently associated with binge drug use and methadone [OR: 0.80 (CI: 0.71–0.89)] was protective against binge drug use. Our study identified an independent association between binge drug use and HIV incidence and demonstrated several high-risk drug practices associated with bingeing. Given the unaddressed public health risks associated with bingeing, a public health response protocol must be developed to minimize the personal and public health risks associated with the binge use of drugs.

Risk-taking behaviors among injecting drug users who obtain syringes from pharmacies, fixed sites, and mobile van needle exchanges

Needle-exchange programs (NEPs) have been shown to be effective in reducing barm related to injection drug use and to act as an important link between the injection drug using community and preventive/treatment services. Different needle-exchange distribution methods may reach different subpopulations of injecting drug users (IDUs). We undertook this study to characterize risk behaviors by primary source of clean needles accessed by IDUs in a city with pharmacy access and fixed and mobile exchange programs. We hypothesized there would be a gradient of risk across the three types of distribution. Data were collected from within the Vancouver Injection Drug Users Study (VIDUS), a prospective cohort study. Participants who primarily obtained clean needles from pharmacies, fixed sites, or mobile exchange vans were compared using the Cochran-Armitage trend test to test for trends in increasing risk behaviors across the three types of distribution. Ordinal multivariate regression was used to adjust the associations for potential confounders. Results illustrate clear trends for increasing risk profiles from pharmacy to fixed site to mobile exchange vans. Van users were generally at higher risk than fixed-site and pharmacy users. Independent predictors of van use were fewer years injecting, difficulty finding needles, Aboriginal ethnicity, incarceration in the previous 6 months, and injecting cocaine daily. An important component of needle-exchange programs is outreach to access those who are at highest risk. Use of distribution beyond fixed sites will improve such outreach, thereby increasing program effectiveness and further preventing the transmission of blood-borne infections.

A qualitative exploration of gender in the context of injection drug use in two US-Mexico border cities.

Injection drug use is of increasing concern along the U.S.–Mexico border where Tijuana and Ciudad (Cd.) Juarez are located. We conducted a qualitative study to explore the context of drug use, with a focus on gender differences. In-depth interviews were conducted with 10 male and 10 female injection drug users (IDUs) in Tijuana and 15 male and 8 female IDUs in Cd. Juarez. Topics included types of drugs used, injection settings, access to sterile needles and environmental influences. Interviews were taped, transcribed and translated. Content analysis was conducted to identify themes. Several themes emerged with respect to gender: (a) how drugs were obtained; (b) where drugs were used; (c) relationship dynamics surrounding drug use; and (d) sex in exchange for money or drugs. Men reported buying and injecting in shooting galleries and other locations, whereas women tended to buy and inject drugs with people they knew and trusted. All men reported having shared syringes in shooting galleries, often with strangers. In these two cities, venue-based interventions may be more appropriate for male IDUs, whereas personal network interventions may be more appropriate among female IDUs.

Elevated rates of HIV infection among young Aboriginal injection drug users in a Canadian setting

ObjectivesRecent reports have suggested that Aboriginal and American Indian people are at elevated risk of HIV infection. We undertook the present study to compare socio-demographic and risk variables between Aboriginal and non-Aboriginal young (aged 13 – 24 years) injection drug users (IDUs) and characterize the burden of HIV infection among young Aboriginal IDUs.MethodsWe compared socio-demographic and risk variables between Aboriginal and non-Aboriginal young IDUs. Data were collected through the Vancouver Injection Drug Users Study (VIDUS). Semi-annually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and Hepatitis C (HCV).ResultsTo date over 1500 Vancouver IDU have been enrolled and followed, among whom 291 were aged 24 years and younger. Of the 291 young injectors, 80 (27%) were Aboriginal. In comparison to non-Aboriginal youth, Aboriginal youth were more likely to test seropositive for either HIV (20% vs 7%, p=< 0.001) or Hepatitis C virus (HCV) (66% vs 38%, p =< 0.001), be involved in sex work and live in the citys IDU epi-centre at baseline. After 48 months of follow-up, Aboriginal youth experienced significantly higher HIV seroconversion rates than non-Aboriginal youth, 27.8 per ppy (95% CI: 13.4–42.2) vs. 7.0 per ppy (95% CI: 2.3–11.8) respectively (log-rank p = 0.005) and the incidence density over the entire follow-up period was 12.6 per 100 pyrs (CI: 6.49–21.96) and 3.9 per 100 pyrs (CI: 1.8–7.3) respectively.InterpretationThese findings demonstrate that culturally relevant, evidence based prevention programs are urgently required to prevent HIV infection among Aboriginal youth.