Patterns of drug use, risky behavior, and health status among persons who inject drugs living in San Diego, California: a latent class analysis

Predictors of substance use disorder treatment and mutual support group participation among Black women across the criminal legal spectrum: A latent class approach

BACKGROUND

The purpose of this study includes: 1) identifying classes of substance-related needs among Black women, and 2) examining the effect of substance-related need classes and culturally-relevant factors on Black women's use of substance use disorder (SUD) treatment and mutual support groups.

METHODS

As part of a longitudinal cohort study, Black women were recruited in prison nearing release, on probation, and in the community without involvement in the criminal legal system (CLS, n=565) and followed-up at 18-months. We conducted a baseline latent class analysis of substance-related needs among Black women. Logistic regression models adjusted for culturally-relevant factors to predict the use of treatment and frequency of mutual support group participation over 18-months among Black women who use drugs.

RESULTS

Four classes by level of needs were found: low, daily marijuana use, high mental health, and high comorbidity. During the 18-month follow-up, women characterized by the high comorbidity need class and with higher scores of religious well-being were more likely to frequently participate in mutual support groups. Non-CLS-involved women were less likely to engage with both treatment and mutual support groups than women from the prison sample at 18-months.

CONCLUSIONS

This study highlights four distinct classes of substance-related needs among Black women, highlighting the complex patterns of behavior and within-racial group differences among Black women. Black women with high comorbidity needs were more likely to participate in mutual support groups, but the latent classes did not predict SUD treatment indicating other non-medical and social contextual need factors may be at play.

No decline in drug overdose deaths in Norway: An ecological approach to understanding at-risk groups and the impact of interventions

Aim: This Norwegian case study examines groups at risk of drug overdose deaths, evidence-based harm reduction interventions, low-threshold services and treatment implemented, as well as trends in drug overdose deaths between 2010 and 2021. We aimed to explore the relevance of interventions for at-risk groups and discuss their potential impact on drug overdose trends. Method/data: Using an ecological approach, we analysed the following: (1) groups identified through latent profile analysis (LPA) among a sample of 413 high-risk drug users collected in 2010-2012, supplemented with other relevant studies up to 2021; (2) published information on harm-reduction interventions, low-threshold services and treatment in Norway; and (3) nationwide drug overdose mortality figures supplemented with published articles on the topic. Results: High-risk drug users in 2010-2012 commonly engaged in frequent illegal drug use, injecting and poly-drug use (including pharmaceutical opioids), which continued into following decade. The interventions implemented between 2010 and 2021 were relevant for at-risk groups identified in the surveys. However, there was no decrease in the trend of drug overdose deaths up to 2021. While relevant interventions may have mitigated a theoretical increase in mortality, new at-risk groups may have contributed to fatal outcomes associated with pharmaceutical opioids. Conclusion: The interventions were relevant to the risk groups identified among high-risk drug users and potentially effective in preventing an increase in drug overdose trends. However, tailored interventions are needed for individuals at risk of death from prescribed opioids. Comprehensive studies encompassing all at-risk populations, including both legal and non-medical users of prescription opioids, are needed.

A Latent Class Analysis of Substance Use and Longitudinal HIV RNA Patterns Among PWH in DC Cohort

People with HIV (PWH) with substance use disorders (SUD) have worse health outcomes than PWH without SUD. Our objective was to characterize substance use patterns and their impact on longitudinal HIV RNA trajectories among those enrolled in an observational study of PWH in care in Washington, DC. Substance use by type (alcohol, cannabis, opioid, stimulant, hallucinogen, inhalant, sedative) was used to identify shared patterns of substance use using Latent Class Analysis (LCA). A multinomial logistic regression model evaluated the association between the resulting substance use classes and the membership probability in longitudinal HIV RNA trajectory groups. There were 30.1% of participants with at least one substance reported. LCA resulted in a three-class model: (1) Low-Level Substance Use, (2) Opioid Use, and (3) Polysubstance. The Opioid and Polysubstance Use classes were more likely to have a mental health diagnosis (45.4% and 53.5%; p < 0.0001). Members in the Opioid Use class were older (median age of 54.9 years (IQR 50.3-59.2) than both the Polysubstance and Low-Level Substance Use Classes (p < 0.0001). There were 3 HIV RNA trajectory groups: (1) Undetectable, (2) Suppressed, and (3) Unsuppressed HIV RNA over 18 months of follow-up. The probability of being in the unsuppressed HIV RNA group trajectory when a member of the Opioid Use or Polysubstance Use classes was 2.5 times and 1.5 times greater than the Low-Level Substance Use class, respectively. The Opioid Use and Polysubstance Use classes, with higher-risk drug use, should be approached with more targeted HIV-related care to improve outcomes.

Neurological, Behavioral, and Pathophysiological Characterization of the Co-Occurrence of Substance Use and HIV: A Narrative Review

Combined antiretroviral therapy (cART) has greatly reduced the severity of HIV-associated neurocognitive disorders in people living with HIV (PLWH); however, PLWH are more likely than the general population to use drugs and suffer from substance use disorders (SUDs) and to exhibit risky behaviors that promote HIV transmission and other infections. Dopamine-boosting psychostimulants such as cocaine and methamphetamine are some of the most widely used substances among PLWH. Chronic use of these substances disrupts brain function, structure, and cognition. PLWH with SUD have poor health outcomes driven by complex interactions between biological, neurocognitive, and social factors. Here we review the effects of comorbid HIV and psychostimulant use disorders by discussing the distinct and common effects of HIV and chronic cocaine and methamphetamine use on behavioral and neurological impairments using evidence from rodent models of HIV-associated neurocognitive impairments (Tat or gp120 protein expression) and clinical studies. We also provide a biopsychosocial perspective by discussing behavioral impairment in differentially impacted social groups and proposing interventions at both patient and population levels.

Drug checking in the fentanyl era: Utilization and interest among people who inject drugs in San Diego, California

BACKGROUND

In North America, overdose rates have steeply risen over the past five years, largely due to the ubiquity of illicitly manufactured fentanyls in the drug supply. Drug checking services (DCS) represent a promising harm reduction strategy and characterizing experiences of use and interest among people who inject drugs (PWID) is a priority.

METHODS

Between February-October 2022, PWID participating in a cohort study in San Diego, CA and Tijuana, Mexico completed structured surveys including questions about DCS, socio-demographics and substance use behaviors. We used Poisson regression to assess factors associated with lifetime DCS use and characterized experiences with DCS and interest in free access to DCS.

RESULTS

Of 426 PWID, 72% were male, 59% Latinx, 79% were experiencing homelessness and 56% ever experienced a nonfatal overdose. One third had heard of DCS, of whom 57% had ever used them. Among the latter, most (98%) reported using fentanyl test strips (FTS) the last time they used DCS; 66% did so less than once per month. In the last six months, respondents used FTS to check methamphetamine (48%), heroin (30%) or fentanyl (29%). Relative to White/non-Latinx PWID, those who were non-White/Latinx were significantly less likely to have used DCS [adjusted risk ratio (aRR): 0.22; 95% CI: 0.10, 0.47), as were PWID experiencing homelessness (aRR:0.45; 95% CI: 0.28, 0.72). However, a significant interaction indicated that non-White/Latinx syringe service program (SSP) clients were more likely to have used DCS than non-SSP clients (aRR: 2.79; CI: 1.09, 7.2). Among all PWID, 44% expressed interest in free access to FTS, while 84% (of 196 PWID) expressed interest in advanced spectrometry DCS to identify and quantify multiple substances.

CONCLUSIONS

Our findings highlight low rates of DCS awareness and utilization, inequities by race/ethnicity and housing situation, high interest in advanced spectrometry DCS versus FTS, and the potential role of SSPs in improving access to DCS, especially among racial/ethnic minorities.

Patterns of opioid use behaviors among patients seen in the emergency department: Latent class analysis of baseline data from the POINT pragmatic trial

INTRODUCTION

The nation's overdose epidemic has been characterized by increasingly potent opioids resulting in more emergency department (ED) encounters over time. ED-based opioid use interventions are growing in popularity; however, they tend to treat people who use opioids as a homogenous population. The current study sought to understand heterogeneity among people who use opioids who encounter the ED by identifying qualitatively different subgroups among participants in an opioid use intervention clinical trial at baseline and examining associations between subgroup membership and multiple correlates.

METHODS

Participants were from a larger pragmatic clinical trial of the Planned Outreach, Intervention, Naloxone, and Treatment (POINT) intervention (n = 212; 59.2 % male, 85.3 % Non-Hispanic White, mean age = 36.6 years). The study employed latent class analysis (LCA) using five indicators of opioid use behavior: preference for opioids, preference for stimulants, usually use drugs alone, injection drug use, and opioid-related problem at ED encounter. Correlates of interest included participants' demographics, prescription histories, health care contact histories, and recovery capital (e.g., social support, naloxone knowledge).

RESULTS

The study identified three classes: (1) noninjecting opioid preferers, (2) injecting opioid and stimulant preferers, and (3) social nonopioid preferers. We identified limited significant differences in correlates across the classes: differences existed for select demographics, prescription histories, and recovery capital but not for health care contact histories. For example, members of Class 1 were the most likely to be a race/ethnicity other than non-Hispanic White, oldest on average, and most likely to have received a benzodiazepine prescription, whereas members of Class 2 had the highest average barriers to treatment and members of Class 3 were the least likely to have been diagnosed with a major mental health illness and had the lowest average barriers to treatment.

CONCLUSIONS

LCA identified distinct subgroups among POINT trial participants. Knowledge of such subgroups assists with the development of better-targeted interventions and can help staff to identify the most appropriate treatment and recovery pathways for patients.

Drug use typology, demographic covariates, and associations with condomless anal sex: A latent class analysis among a U.S. national cohort of men who have sex with men

BACKGROUND

Prior research has shown that men who have sex with men (MSM) who use drugs are at increased risk of sexually transmitted infections (STI) and Human Immunodeficiency Virus (HIV). Often, MSM who use drugs use multiple substances at once and research has indicated that certain substances are used in combination more frequently. As a vulnerable population, it is important to understand the various ways in which this population uses drugs in order to structure prevention, harm reduction, and treatment programs to their needs.

METHODS

Data for this analysis were taken from a cohort of geographically diverse U.S. national sample of cisgender men who have sex with men (n = 6111). After assessing prevalence of drug use in the sample, we used iterative latent class analysis to determine substance use classes for 10 substances. After a model was selected, class assignments were examined for association with mean number of insertive and receptive condomless anal sex (CAS) partners in the past three months.

RESULTS

The final model indicated six latent classes: class 1 = "cannabis use" (n = 1,996), class 2 = "diverse use" (n = 299), class 3 = "cocaine and inhalant use" (n = 421), class 4 = "methamphetamine, GHB, and inhalant use" (n = 345), class 5 = "no use" (n = 2431), class 6 = "sedative use" (n = 619). Age, race, annual income, residence in EHE jurisdictions, past history of houselessness, and past history of incarceration was significantly associated with membership in some classes. In outcome modeling, participants best assigned to Class 4 had the highest mean number of insertive (Mean = 9.70, 95% CI: 5.92 - 13.47) and receptive (Mean = 8.71, 95% CI: 6.75 - 10.66) condomless anal sex (CAS) partners in the prior three months.

CONCLUSION

The six heterogenous classes may indicate discrete typologies of use behavior corresponding to different settings or activities, which may themselves differ by regional HIV incidence trends and participant demographics. Programs seeking to address substance use among MSM may be well served to tailor toward these divergent clusters of substance use.

Trends and distinct profiles of persons who inject drugs in the United States, 2015-2019

Drug injection represents a major health problem in the US, with severe health consequences including the transmission of blood-borne infections. An examination of the most recent trends in drug injection is warranted by the fast-evolving drug epidemic and recent policy changes such as the federal funding ban on needle exchange programs. This research examines current drug injection trends, patterns, and socioeconomic and behavioral profiles of people who inject drugs (PWID). Data were derived from the 2002 to 2019 National Survey on Drug Use and Health (NSDUH). After examining the annual prevalence of drug injection since 2002, a latent class analysis was conducted to identify drug injection and other substance misuse patterns among PWID using the latest (2015-2019) NSDUH datasets. Associations between class membership and behavioral health comorbidities and treatment receipt were also assessed. The drug injection prevalence among US adults aged 18-64 increased from 0.21% in 2002/2004 to 0.36% in 2017/2019. Three distinctive groups were identified: the heroin injection group (45.2%), the methamphetamine injection group (28.0%), and the multi-drug injection group (26.8%). The methamphetamine injection group reported greater risks of experiencing serious psychological distress, suicidality, and limited substance use treatment. Special attention is needed for those who primarily injected methamphetamine. Programs to promote harm reduction and increase access to addiction treatment need to be expanded in at-risk communities while accounting for their distinct socioeconomic and drug use/misuse profiles.

Analysis of drug-related infectious diseases in people who inject drugs - Pilsen Region, 2003-2018

OBJECTIVES

The aim of the study is to analyse drug-related infectious diseases (DRID) rates for people who inject drugs (PWID) in the Pilsen Region in order to identify the main determiners of infection risk and also to provide a foundation for comparison between this region and the others in the Czech Republic.

METHODS

In a descriptive cross-sectional study, we analysed the Pilsen Region's data on PWID. The data was transcribed from the 2003 to 2018 internal database of the Ulice Outreach Programme. In addition to the data regarding the testing of DRID, we analysed commercial sex work (CSW) and the PWID's duration of drug use, age and current address. The statistical analysis was performed using SPSS, primarily employing logistic regression (i.e., backward elimination method) to explore predictors of seropositivity. Moreover, we calculated its prevalence from an epidemiological perspective.

RESULTS

In total, 384 PWID were tested, from which 54.7% were males, and 84.1% were from Pilsen. The average age for initiation of using drug was 19.37 years. The most used drug was methamphetamine (64.8%), 77 women (20.1%) were reported to be CSW. The prevalence of DRID was as follows: hepatitis C virus (HCV) 37.24%, syphilis 1.82%, hepatitis B virus (HBV) 0.78%, and HIV infection 0.26%. The analysis showed that men had a lower risk of syphilis than women. Individuals who started their drug use via injection had a 1.365-times higher risk of DRID in comparison to those who initiated intravenous drug use later in their drug-using lives. We identified a significant association between the drug type and the risk of HCV infection: the main predictor of seropositivity was the use of fentanyl, which posed a 1.930-times higher risk than in the case of methamphetamine.

CONCLUSIONS

This study is the first descriptive cross-sectional study implemented in the Pilsen Region in the Czech Republic with a focus on the subpopulation of PWID with individual data. A high prevalence of HCV infection still persists but the prevalence of HBV and HIV infections in this study (and generally in the Czech Republic) is relatively low compared to foreign studies. Syphilis is not closely associated with injecting-drug use, but rather with the sexual behaviour of the people who use drugs intravenously. The most important predictor of seropositivity for syphilis was CSW. We also found the duration of being a CSW to be significant influence. The women who had been CSWs for less than 5 years had a significantly lower risk of syphilis than those who had prostituted for more than 5 years.

Latent Classes of Polysubstance Use and Associations with HIV Risk and Structural Vulnerabilities among Cisgender Women Who Engage in Street-Based Transactional Sex in Baltimore City

We describe patterns of polysubstance use and associations with HIV risk-related behaviors among women engaged in street-based transactional sex, an understudied yet important population and area of research. This sample was restricted to cisgender women who reported drug use (n = 244) in the baseline of the longitudinal SAPPHIRE cohort study. Latent class analysis (LCA) was conducted using drug use measures (route of administration (injection/non-injection); type of drug (specific opioids, stimulants)) and selection based on fit statistics and qualitative interpretation of the classes. Polysubstance use was prevalent (89% ≥ 2), and 68% had injected drugs in the past 3 months. A three-class solution was selected: Class 1 ("heroin/cocaine use", 48.4% of sample), Class 2 ("poly-opioid use", 21.3%), and Class 3 ("poly-route, polysubstance use", 30.3%). Class 3 was significantly younger, and Class 2 was disproportionately non-White. Women reported high levels of housing (63%) and food (55%) insecurity, condomless sex with clients (40%), and client-perpetrated violence (35%), with no significant differences by class. Obtaining syringes from syringe services programs differed significantly by class, despite injection behaviors in all classes. Tailored HIV and overdose prevention programming that considers drug use patterns would strengthen their impact.

Mortality among people who inject drugs: a prospective cohort followed over three decades in Baltimore, MD, USA

BACKGROUND AND AIMS

During the past decades, people who inject drugs (PWID) have been impacted by the development of combination antiretroviral therapy (cART) to combat HIV/AIDS, the prescription opioid crisis and increased use of lethal synthetic opioids. We measured how these dynamics have impacted mortality among PWID in an urban US city.

DESIGN

Prospective cohort study using data from the AIDS Linked to the Intravenous Experience (ALIVE).

SETTING

Baltimore, MD, USA from 1988 to 2018.

PARTICIPANTS

A total of 5506 adult PWIDs (median age at baseline 37 years).

MEASUREMENTS

Mortality was identified by linkage to National Death Index-Plus (NDI-Plus) and categorized into HIV/infectious disease (HIV/ID) deaths, overdose and violence-related (drug-related) deaths and chronic disease deaths. Person-time at risk accrued from baseline and ended at the earliest of death or study period. All-cause and cause-specific mortality were calculated annually. The Fine & Gray method was used to estimate the subdistribution hazards of cause-specific deaths accounting for competing risks.

FINDINGS

Among 5506 participants with 84 226 person-years of follow-up, 43.9% were deceased by 2018. Among all deaths, 30.5% were HIV/ID deaths, 24.4% drug-related deaths and 33.3% chronic disease deaths. Age-standardized all-cause mortality increased from 23 to 45 per 1000 person-years from 1988 to 1996, declined from 1996 to 2014, then trended upward to 2018. HIV/ID deaths peaked in 1996 coincident with the availability of cART, then continuously declined. Chronic disease deaths increased continuously as the cohort aged. Drug-related deaths declined until 2011, but increased more than fourfold by 2018. HIV/HCV infection and active injecting were independently associated with HIV/ID and drug-related deaths. Female and black participants had a higher risk of dying from HIV/ID deaths and a lower risk of dying from drug-related deaths than male and non-black participants.

CONCLUSIONS

Deaths in Baltimore, MD, USA attributable to HIV/ID appear to have declined following the widespread use of combination antiretroviral therapy. Increases in the rates of drug-related deaths in Baltimore were observed prior to and continue in conjunction with national mortality rates associated with the opiate crisis.

The association of opioid use disorder and homelessness nationally in the veterans health administration

BACKGROUND

Substance use disorder (SUD) is a major risk factor for homelessness, but the specific association of opioid use disorder (OUD) and homelessness in the context of their shared risk factors has not been the focus of prior studies. We used national data from the United States Veterans Health Administration (VHA) to examine the association of OUD and homelessness in the context of shared risk factors.

METHODS

In this cross-sectional analysis of veterans who received VHA care during Fiscal Year 2012 (N = 5,450,078), we compared the prevalence of OUD and other sociodemographic, and clinical factors among homeless and non-homeless veterans. We estimated the odds ratio for homelessness associated with OUD alone, and after adjusting for other factors through multivariate logistic regression.

RESULTS

Homeless veterans had substantially higher prevalence of OUD than other VHA patients (7.7 % Vs 0.6 %) and OUD was associated with 13 times higher unadjusted odds of homelessness (Odds Ratio [OR] 13.36, 95 % CI 13.09-13.62), which decreased with adjustment for sociodemographic factors (black race, mean income and age), other SUD, medical, and psychiatric diagnoses (final OR 1.57, 95 % CI 1.53-1.61). Other SUDs (alcohol, cannabis, cocaine, and hallucinogens) showed similar or slightly higher odds of homelessness as OUD in the final model.

CONCLUSIONS

OUD was strongly associated with homelessness among US veterans although this association was largely but not entirely attenuated by shared sociodemographic and co-morbid risk factors including several other SUDs. Treatment of homeless veterans with OUD should address socio-economic vulnerabilities and other co-morbidities in addition to treatments for OUD.

Risky Sexual Behavior of Young Adults in Hong Kong: An Exploratory Study of Psychosocial Risk Factors

There is limited knowledge of the prevalence and nature of risky sexual behavior (RSB) among young adults in Hong Kong. This cross-sectional study explored the psychosocial risk factors of RSB with a sample of 1,171 Hong Kong university students (aged 18-40 years). Grounded in the theoretical propositions of several criminological theories (i.e., the theories of self-control, general strain, social learning, social control, and routine activity), engagement in three types of RSB (i.e., general, penetrative, and non-penetrative) was studied alongside a range of psychosocial risk factors. Relative to female participants, male participants reported significantly higher mean levels of general, penetrative, and non-penetrative RSB. Male participants also reported significantly higher mean levels of negative temperament, use of alcohol and other drugs, and paraphilic interests than female participants, who reported significantly higher mean levels of self-control and social bonds than their male counterparts. The results of multivariate analyses (i.e., OLS regressions) revealed that, to a large extent, the male and female participants shared a similar set of psychosocial risk factors (i.e., use of alcohol and other drugs, and paraphilic interest) for their involvement in general, penetrative, and non-penetrative RSB. Furthermore, a high level of negative temperament was significantly associated with penetrative RSB for both genders, while a high level of perceived neighborhood disorganization was found to be an important factor in the participation of females in general, penetrative, and non-penetrative RSB. The findings of this study may have important implications for practice in regard to reducing, if not entirely preventing, the tendency to engage in RSB.

Co-use of methamphetamine and opioids among people in treatment in Oregon: A qualitative examination of interrelated structural, community, and individual-level factors

BACKGROUND

Rates of methamphetamine use and methamphetamine-related deaths have increased steadily in the United States in recent years. Methamphetamine is increasingly present in opioid-related deaths. An initial study of de-identified urine specimens (n = 102) collected at a drug treatment program between 2017 and 2018 indicated that 61% of specimens contained methamphetamine; of the specimens containing methamphetamine, people were, on average, five years younger than those who tested negative for methamphetamine; and non-fentanyl opioids were more than three times as common in methamphetamine positive specimens. The National Drug Early Warning System (NDEWS) Coordinating Center initiated a HotSpot Study to assess whether there was an emerging dynamic in the area, or if enhanced data collection could give insights into the co-use of methamphetamine and opioids.

METHODS

A qualitative study, grounded in principles of rapid ethnographic assessment and a social science/anthropological framework was conducted and used methodological complementarity to contextualize results from the initial urinalysis study. Targeted sampling was conducted at two treatment sites. Program staff and patients were recruited to participate in focus groups and semi-structured interviews to assess structural, community, and individual-level factors impacting methamphetamine and opioid co-use.

RESULTS

Within our broader framework of structural, community, and individual-level factors intersecting co-use, our data yielded three sub-themes: 1) the circulation of stigma regarding methamphetamine use was consistently described by both patients and staff and this intersected structural changes in treatment policy and suggested compounded stigma; 2) community-level factors and temporality were important for understanding patterns of methamphetamine use and for further interpreting the initial urinalysis; 3) patient rationales regarding the co-use of methamphetamine and opioids included strategies to mitigate the harms of heroin, as well as to detox or titrate the effects of heroin.

CONCLUSION AND IMPLICATIONS

Using an ethnographically-oriented and social science/anthropological approach and methodological complementarity to contextualize the prior urinalysis study demonstrates how behavioral variables cannot be abstracted from larger socio-structural and community contexts which impact people's decision-making process regarding co-use of methamphetamine and opioids. Further, by grounding our analysis in the meaning-centered and experiential narratives of people who use drugs, our research demonstrates the importance of considering the expertise of people who co-use opioids and methamphetamine as central for informing future sustainable program planning to address co-use that also accounts for the interrelationship between structural, community, and individual-level factors.

Interest in reducing methamphetamine and opioid use among syringe services program participants in Washington State

BACKGROUND

Methamphetamine use is increasing, and opioid use remains elevated in the US. Understanding interest in reducing/stopping substance use among people who inject drugs (PWID), as well as types of help wanted, can inform interventions.

METHODS

Data from the 2019 Washington State Syringe Exchange Survey were used in logistic regression analyses to assess if demographics, substance use, and concern about anxiety or depression were associated with interest in reducing/stopping substance use among people whose main drug was methamphetamine or opioids. Types of help wanted to reduce/stop use are reported.

RESULTS

Of 583 participants included, 76 % reported opioids were their main drug, of whom 82 % were interested in reducing/stopping their opioid use. 24 % reported methamphetamine as their main drug, of whom 46 % were interested in reducing/stopping their methamphetamine use. Among those whose main drug was an opioid, female gender (AOR:2.19, p = .023) and concern about depression (AOR:3.04, p = .002) were associated with interest in reducing/stopping opioid use. Among participants whose main drug was methamphetamine, being in jail in the past year and having an infection likely related to injection (e.g., abscess) in the past year were associated with over twice the odds of interest in reducing/stopping methamphetamine use (AOR:2.14, p = .056 and 2.43, p = .052, respectively); however, these findings were not significant. Several types of help to reduce/stop use were endorsed.

CONCLUSION

There were high, though differing, levels of interest in reducing/stopping opioid or methamphetamine use and in a range of support services. PWID should be asked about interest in reducing/stopping use and provided appropriate support.

Estimating the contribution of stimulant injection to HIV and HCV epidemics among people who inject drugs and implications for harm reduction: A modeling analysis

BACKGROUND

Stimulants, such as amphetamines and cocaine, are widely injected among people who inject drugs (PWID). Systematic reviews indicate stimulant injection is associated with HIV and HCV among PWID. Using these associations, we estimated the contribution of stimulant injection to HIV and HCV transmission among PWID.

METHODS

We modeled HIV and HCV transmission among PWID, incorporating excess injecting and sexual risk among PWID who inject stimulants. We simulated three illustrative settings with different stimulants injected, prevalence of stimulant injecting, and HIV/HCV epidemiology. We estimated one-year population attributable fractions of stimulant injection on new HIV and HCV infections, and impact of scaling up needle-syringe programs (NSP).

RESULTS

In low prevalence settings of stimulant injection (St. Petersburg-like, where 13 % inject amphetamine), 9% (2.5-97.5 % interval [95 %I]: 6-15 %) and 7% (95 %I 4-11 %) of incident HIV and HCV cases, respectively, could be associated with stimulant injection in the next year. With moderate stimulant injection (Montreal-like, where 34 % inject cocaine), 29 % (95 %I: 19-37 %) and 19 % (95 %I: 16-21 %) of incident HIV and HCV cases, respectively, could be associated with stimulant injection. In high-burden settings like Bangkok where 65 % inject methamphetamine, 23 % (95%I:10-34%) and 20 % (95%I: 9-27%) of incident HIV and HCV cases could be due to stimulant injection. High-coverage NSP (60 %) among PWID who inject stimulants could reduce HIV (by 22-65 %) and HCV incidence (by 7-11 %) in a decade.

DISCUSSION

Stimulant injection contributes substantially to HIV and HCV among PWID. NSP scale-up and development of novel interventions among PWID who inject stimulants are warranted.

Characterizing profiles of polysubstance use among high school students in Baltimore, Maryland: A latent class analysis

BACKGROUND

Adolescent drug use has long term health consequences, like substance use disorders and psychiatric illnesses. Proximal health risks, especially for overdose, are amplified when multiple substances are combined. Existing literature on polysubstance use among adolescents has largely focused on alcohol, tobacco, and marijuana, but has largely excluded other drugs like opioids. Understanding how adolescents combine illicit drugs is essential for intervening to prevent poor health outcomes.

METHODS

We aimed to explore patterns of lifetime polysubstance use among adolescents in Baltimore City. We used data on 9th-12th graders recruited to participate in the 2017 local Baltimore Youth Risk Behavior Survey who reported any lifetime drug use (n = 387; 60 % female, 77 % non-Hispanic Black). We then conducted a latent class analysis using 10 indicators of lifetime drug and alcohol use. After selecting the class model, we tested for associations between the class profiles and race, sex, school grade, and lifetime injection drug use.

RESULTS

We identified three profiles of lifetime polysubstance use in our sample: alcohol and marijuana (68.6 % of sample), polysubstance (22.0 %), and alcohol/pain medication/inhalant use (9.4 %). Members of the polysubstance use class were more likely to be male and to report injection drug use.

CONCLUSIONS

Understanding broader patterns of drug use beyond alcohol, tobacco and marijuana among adolescents is a crucial step towards preventing adverse drug and health-related outcomes later in life. More research is needed to characterize the full health impact of youth polysubstance use patterns and related risk behaviors like injection drug use.

Associations between housing stability and injecting frequency fluctuations: findings from a cohort of people who inject drugs in Montréal, Canada

BACKGROUND

The relationship between housing stability and drug injecting is complex, as both outcomes fluctuate over time. The objectives were to identify short-term trajectories of housing stability and injecting frequency among people who inject drugs (PWID) and examine how patterns of injecting frequency relate to those of housing stability.

METHODS

At three-month intervals, PWID enrolled between 2011 and 2016 in the Hepatitis Cohort completed an interviewer-administered questionnaire and were tested for hepatitis C and HIV infections. At each visit, participants reported, for each of the past three months, the accommodation they lived in the longest (stable/unstable) and the number of injecting days (0-30). Group-based dual trajectory modeling was conducted to identify housing stability and injecting frequency trajectories evolving concomitantly over 12 months and estimate the probabilities of following injecting trajectories conditional upon housing trajectories.

RESULTS

386 participants were included (mean age 40.0, 82 % male). Three housing stability trajectories were identified: sustained (53 %), declining (20 %), and improving (27 %). Five injecting frequency trajectories were identified: sporadic (26 %), infrequent (34 %), increasing (15 %), decreasing (11 %), and frequent (13 %). PWID with improving housing were less likely to increase injecting (8 %) compared to those with sustained (17 %) or declining housing (17 %).

CONCLUSIONS

Improving housing was associated with a lower probability of increasing injecting compared to declining housing, while sustained housing stability was associated with a higher probability of increasing injecting compared to improving housing. Therefore, policies to improve PWID's access to stable housing are warranted and may reduce, to some extent, drug injecting and related harms.

Adolescent Anabolic-Androgenic Steroid Use in Association with Other Drug Use, Injection Drug Use, and Team Sport Participation

Introduction

The majority of epidemiologic research on adolescent non-medical anabolic-androgenic steroid (AAS) use was conducted in the 1990s and early 2000s, indicating a need to update evidence for the modern era. We aim to understand the prevalence of AAS use among US adolescents and assess associations between AAS use, sports participation, other drug use, and injection drug use (IDU).

Methods

Using data from the 2017 National Youth Risk Behavior Survey, we estimated the prevalence of AAS use and tested for associations between AAS use, sports participation, and drug use, overall and by sex.

Results

The prevalence of AAS use was 2.98%. The prevalence among boys (3.46%) was higher than among girls (2.41%). AAS use was high among youth with lifetime heroin use (64.41%) and IDU (64.42%). There was no association between AAS and team sport participation (p=0.61).

Conclusions

Our results indicate that adolescent AAS use is an aspect of polysubstance use rather than a substance used solely for performance enhancement in sports. Research with adolescents should be mindful of the overlap of heroin and AAS use among youth with IDU.

Opioid Misuse Among HIV-Positive Adults in Medical Care: Results From the Medical Monitoring Project, 2009-2014

BACKGROUND

People living with HIV are prescribed opioids more often and at higher doses than people who do not have HIV, and disproportionately experience risk factors for substance use disorder, which suggests they could be at increased risk of the misuse of opioids. Researchers also suggest that opioid misuse negatively affects various HIV clinical outcomes, increasing the risk of transmission to partners with an HIV-negative status.

METHODS

We calculated weighted percentages and 95% confidence intervals to estimate substance use characteristics among a probability sample of 28,162 HIV-positive adults receiving medical care in the United States who misused opioids (n = 975). Then, we used Rao-Scott χ tests to assess bivariate associations between opioid misuse and selected characteristics.

RESULTS

In all, 3.3% misused opioids. Misuse was more common among young adults, males, and non-Hispanic whites. Persons who misused opioids were less likely to: have been prescribed antiretroviral therapy (ART) (88.7%), report being adherent to ART medications in the past 3 days (78.1%), and have durable viral suppression (54.3%) than persons who did not misuse opioids (92.5%, 87.7%, and 64.7%, respectively). Persons who misused opioids were more likely to report condomless sex with partners of negative or unknown HIV status while not durably virally suppressed (11.7% vs 3.4%) than persons who did not misuse opioids.

CONCLUSIONS

Opioid misuse among adults receiving HIV medical care is associated with inadequate ART adherence, insufficient durable viral suppression, and higher risk of HIV transmission to sexual partners.

CAM Practices and Treatment Adherence Among Key Subpopulations of HIV+ Latinos Receiving Care in the San Diego-Tijuana Border Region: A Latent Class Analysis

Latinos living in the United States-Mexico border region bear a disproportionate HIV/AIDS burden compared to individuals living in the interior of both nations and face a constellation of barriers that determine their ability to access and adhere to HIV care. Use of complementary and alternative medicine (CAM) may be associated with suboptimal treatment adherence. Sociodemographic factors, health practices, and social determinants of health unique to the border region may further contribute to health disparities that undermine care engagement and continuity. Improved understanding of HIV-positive Latino subgroups and their risk profiles can lead to more effective, targeted clinical and public health interventions. We undertook this study to identify and characterize distinct classes of HIV-positive Latinos in the San Diego-Tijuana border region, differentiated by HIV and border-related factors, utilizing latent class analysis. We investigated relationships between class membership and CAM utilization and self-reported antiretroviral therapy (ART) adherence. Five distinct classes were identified with unique demographic, HIV risk, and border mobility profiles. CAM was recently used by nearly half of each class, though there were significant differences in the proportion of CAM use by class ranging from 44.4 to 90.9%. As well, all classes were currently receiving ART at similarly high rates and ART adherence outcomes were not significantly different based on class. Findings highlight the significant use of CAM by all HIV-positive Latinos in the border region and imply the need for a research framework which appropriately acknowledges the heterogeneous nature of this population, such as intersectionality. Further research is recommended into understanding how patients integrate CAM into HIV treatment and the risks and benefits of incorporating CAM into HIV treatment.

Identifying high risk subgroups of MSM: a latent class analysis using two samples

Background

Latent class analyses (LCA) are increasingly being used to target specialized HIV interventions, but generalizability of emergent population structures across settings has yet to be considered. We compare LCA performed on two online samples of HIV negative Chinese men who have sex with men (MSM) to detect more generalizable latent class structures and to assess the extent to which sampling considerations impact the validity of LCA results.

Methods

LCAs were performed on an 1) nationwide online survey which involved no in-person contact with study staff and a 2) sentinel surveillance survey in which participants underwent HIV and syphilis testing in the city of Guangzhou, both conducted in 2014. Models for each sample were informed by risk factors for HIV acquisition in MSM that were common to both datasets.

Results

An LCA of the Guangzhou sentinel surveillance data indicated the presence of two relatively similar classes, differing only by the greater tendency of one to report group sex. In contrast an LCA of the nationwide survey identified three classes, two of which shared many of the same features as those identified in the Guangzhou survey, including the fact that they were mainly distinguished by group sex behaviors. The final latent class in the nationwide survey was composed of members with notably few risk behaviors.

Conclusions

Comparisons of the latent class structures of each sample lead us to conclude that the nationwide online sample captured a larger, possibly more representative group of Chinese MSM comprised of a larger, higher risk group and a small yet distinct lower group with few reported behaviors. The absence of a lower risk group in the Guangzhou sentinel surveillance dataset suggests that MSM recruited into studies involving free HIV/STI testing may oversample MSM with higher risk behaviors and therefore greater risk perception. Lastly, two types of higher risk MSM were emergent across both samples distinguished largely by their recent group sex behaviors. Higher odds not only of self-reported HIV infection but also of closeted tendencies and gender fluid identities in this highest risk group suggest that interacting factors drive individual and structural facets of HIV risk.

Results of a Naloxone Screening Quality-Improvement Project in an Academic Emergency Department

BACKGROUND

The Emergency Department (ED) is a medical setting increasingly utilized by opioid users. In January 2016, our health system initiated a take-home naloxone education and distribution program. From July to August 2016, screening was performed in the ED to identify patients for take-home naloxone.

OBJECTIVE

To evaluate the outcomes of routine screening for take-home naloxone in the ED setting and to determine key screening questions. Secondary analysis of Electronic Health Records for discrete elements that could help identify individuals for naloxone.

METHODS

This is a single-center, retrospective cohort study conducted at two EDs within an academic health system. A screening tool was verbally administered to a convenience sample of ED patients as part of a pilot project to identify patients for overdose education and naloxone. Patient charts were reviewed retrospectively for pre-determined historical elements, medications prescribed, and substance use history. Descriptive and comparative analysis using Fisher two-tailed tests were performed with regard to historical elements, naloxone recommendation and prescription.

RESULTS

A total of 182 patients were included. Following screening, 58 (31.9%) were identified as candidates for take-home naloxone. Of those, 36 (62.1%) accepted naloxone recommendation and 19 (32.8%) were prescribed naloxone. Individuals not prescribed naloxone despite recommendation either declined naloxone 22 (37.9%) or were not prescribed naloxone 17 (29.3%). Subanalysis of questions with binary yes/no answers (N = 171) demonstrated significant prediction of both naloxone recommendation (ROC = 0.944) and prescription (ROC = 0.897).

CONCLUSIONS

Routine screening for take-home naloxone can help identify patients at-risk for opioid overdose and increase naloxone access in the ED.

A latent class approach to identify multi-risk profiles associated with phylogenetic clustering of recent hepatitis C virus infection in Australia and New Zealand from 2004 to 2015

INTRODUCTION

Over the last two decades, the incidence of hepatitis C virus (HCV) co-infection among men who have sex with men (MSM) living with HIV began increasing in post-industrialized countries. Little is known about transmission of acute or recent HCV, in particular among MSM living with HIV co-infection, which creates uncertainty about potential for reinfection after HCV treatment. Using phylogenetic methods, clinical, epidemiological and molecular data can be combined to better understand transmission patterns. These insights may help identify strategies to reduce reinfection risk, enhancing effectiveness of HCV treatment as prevention strategies. The aim of this study was to identify multi-risk profiles and factors associated with phylogenetic pairs and clusters among people with recent HCV infection.

METHODS

Data and specimens from five studies of recent HCV in Australia and New Zealand (2004 to 2015) were used. HCV Core-E2 sequences were used to infer maximum likelihood trees. Clusters were identified using 90% bootstrap and 5% genetic distance threshold. Multivariate logistic regression and latent class analyses were performed.

RESULTS

Among 237 participants with Core-E2 sequences, 47% were in a pair/cluster. Among HIV/HCV co-infected participants, 60% (74/123) were in a pair/cluster, compared to 30% (34/114) with HCV mono-infection (p < 0.001). HIV/HCV co-infection (vs. HCV mono-infection; adjusted odds ratio (AOR), 2.37, 95% confidence interval (CI), 1.45, 5.15) was independently associated with phylogenetic clustering. Latent class analysis identified three distinct risk profiles: (1) people who inject drugs, (2) HIV-positive gay and bisexual men (GBM) with low probability of injecting drug use (IDU) and (3) GBM with IDU & sexual risk behaviour. Class 2 (vs. Class 1, AOR 3.40; 95% CI, 1.52, 7.60), was independently associated with phylogenetic clustering. Many clusters displayed homogeneous characteristics, such as containing individuals exclusively from one city, individuals all with HIV/HCV co-infection or individuals sharing the same route of acquisition of HCV.

CONCLUSIONS

Clusters containing individuals with specific characteristics suggest that HCV transmission occurs through discrete networks, particularly among HIV/HCV co-infected individuals. The greater proportion of clustering found among HIV/HCV co-infected participants highlights the need to provide broad direct-acting antiviral access encouraging rapid uptake in this population and ongoing monitoring of the phylogeny.

A latent class analysis of alcohol and drug use immediately before or during sex among women

BACKGROUND

Alcohol and drug use by women is related to high-risk sexual practices and protective behaviors.

OBJECTIVES

To determine sexual risk and protective behaviors using information about women's drug use immediately before or during sex.

METHODS

Latent class analysis using PROC LCA in SAS software was used to determine classes of women using both past 30-day drug use and before or during sex. Participants were recruited from a community-based research site located in a low socio-economic area of Los Angeles County and completed the Risk Behavior Assessment, which elicits information on drug and sex risk behaviors.

RESULTS

The Risk Behavior Assessment and HIV and sexually transmitted infections testing was obtained on 812 women. Five distinct groups were identified by PROC LCA: An Abstinent group comprised of 26% of participants; an Alcohol and Marijuana group (16%); an Amphetamine group (11%); a No Sex-with-Alcohol group (37%); and a Poly Drug group (11%). Multinomial logistic regression revealed that sexual behaviors and condom use were different across the five groups: The Alcohol and Marijuana group had a higher odds of vaginal intercourse, while the No Sex-with-Alcohol group was most likely to use condoms for vaginal intercourse. The Poly Drug group had the highest risk for anal intercourse while the Amphetamine and Poly Drug groups had high proportions of women with injection-drug using and men-who-have-sex-with-men sexual partners.

CONCLUSION

Identifying women based on drug use immediately before or during sex can help providers understand prevention and risk-reduction practices and interventions for drug-using women.

A fragmented code: The moral and structural context for providing assistance with injection drug use initiation in San Diego, USA

BACKGROUND

Injection drug use initiation is shaped by social networks and structural contexts, with people who inject drugs often assisting in this process. We sought to explore the norms and contexts linked to assisting others to initiate injection drug use in San Diego, USA, to inform the development of structural interventions to prevent this phenomenon.

METHODS

We undertook qualitative interviews with a purposive sample of people who inject drugs and had reported assisting others to initiate injection (n = 17) and a sub-sample of people who inject drugs (n = 4) who had not reported initiating others to triangulate accounts. We analyzed data thematically and abductively.

RESULTS

Respondents' accounts of providing initiation assistance were consistent with themes and motives reported in other contexts: of seeking to reduce harm to the 'initiate', responding to requests for help, fostering pleasure, accessing resources, and claims that initiation assistance was unintentional. We developed analysis of these themes to explore initiation assistance as governed by a 'moral code'. We delineate a fragmented moral code which includes a range of meanings and social contexts that shape initiation assistance. We also show how assistance is happening within a structural context that limits discussion of injection drug use, reflecting a prevailing silence on drug use linked to stigma and criminalization.

CONCLUSIONS

In San Diego, the assistance of others to initiate injection drug use is governed by a fragmented moral code situated within particular social norms and contexts. Interventions that address the social and structural conditions shaped by and shaping this code may be beneficial, in tandem with efforts to support safe injection and the reduction of injection-related harms.

A virtual academy of polydrug use: Masters, novices and the art of combinations

Aims

Information technology has become an essential part of drug culture, providing a platform for lay knowledge concerning drug use. Due to the co-effects of different substances, making substance "combos" requires advanced skills to enhance pleasures and manage risks. In this study, we focussed on Finnish and Swedish online discussions as a context for learning and sharing experiences of combining substances.

Methods

Taking influences from positioning theory, we used qualitative methods to map what kinds of mutual interactive positions related to the expertise in polydrug use online discussants take and how these positions are negotiated and reformulated in the online setting. We reflect these results through Howard S. Becker's theory of social learning, according to which becoming a drug user is a process that occurs in interaction with other users, as the beginners need a model and advice from experienced users in order to claim their place in the users' community.

Results

In online forums, users discuss the risks and pleasures of combining drugs - on the one hand, in relation to different situations and, on the other hand, in relation to different competence positions. This occurs by asking for advice, presenting one's knowledge, challenging others, repositioning oneself, defending one's position or proving one's competence.

Conclusion

Online discussion forums constitute a kind of virtual academy where knowledge of the pleasures and risks of combining substances is produced and circulated, and where experienced masters mediate their expertise to less experienced novices.

Patterns of substance use and mortality risk in a cohort of 'hard-to-reach' polysubstance users

AIMS

To examine the mortality risk in a cohort of 'hard-to-reach' polysubstance users and its putative associations with substance use. Specifically, we estimated all-cause mortality risk as a function of individual substance use indicators, and then as a function of their complex, 'real-life' patterns as identified through latent class analysis (LCA).

DESIGN

Prospective cohort study among street- and low-threshold service-recruited polysubstance users included between September and November 2013 and followed through the National Cause of Death Registry until 31 October 2015.

SETTING

Seven Norwegian cities.

PARTICIPANTS

A total of 884 users of illegal opioids and/or stimulants. Of these, 357 were in opioid substitution treatment (OST) at the time of inclusion. Forty-four participants died during follow-up.

MEASUREMENTS

Primary outcome: all-cause mortality risk. Unadjusted and adjusted Cox proportional hazard (PH) regression models (covariates: male, age, homelessness/shelter use, overdose experience, OST status, years of injecting, individual substance use indicators, city, use patterns). LCA models estimated separately for those in and those not in OST due to measurement invariance.

FINDINGS

The crude mortality rate was 2.52 per 100 person-years. Standardized mortality ratio was 26.11 [95% confidence interval (CI) = 10.06-54.87] for women and 10.71 (95% CI = 6.39-16.81) for men. No single drug use indicator, such as 'heroin injection' or 'number of drugs used', was associated with the mortality risk. However, meaningful use patterns were identified; three OST and non-OST patterns each. The non-OST patterns 'polysubstance injectors' [hazard ratio (HR) = 3.45, 95% CI = 0.98-12.14] and 'low frequent injectors' (HR = 3.17, CI = 1.05-9.56) were associated significantly with the mortality risk even when adjusted for other known risk factors.

CONCLUSIONS

In a Norwegian prospective cohort study, 'hard-to-reach' polysubstance users had a more than 10 times higher mortality risk than the general population. Mortality risk was not a function of any single drug use indicator, but two distinct combinations of substances, frequencies and routes of administration were associated with the mortality risk.

Big Data's Role in Precision Public Health

Precision public health is an emerging practice to more granularly predict and understand public health risks and customize treatments for more specific and homogeneous subpopulations, often using new data, technologies, and methods. Big data is one element that has consistently helped to achieve these goals, through its ability to deliver to practitioners a volume and variety of structured or unstructured data not previously possible. Big data has enabled more widespread and specific research and trials of stratifying and segmenting populations at risk for a variety of health problems. Examples of success using big data are surveyed in surveillance and signal detection, predicting future risk, targeted interventions, and understanding disease. Using novel big data or big data approaches has risks that remain to be resolved. The continued growth in volume and variety of available data, decreased costs of data capture, and emerging computational methods mean big data success will likely be a required pillar of precision public health into the future. This review article aims to identify the precision public health use cases where big data has added value, identify classes of value that big data may bring, and outline the risks inherent in using big data in precision public health efforts.

Drug use and phylogenetic clustering of hepatitis C virus infection among people who use drugs in Vancouver, Canada: A latent class analysis approach

This study estimated latent classes (ie, unobserved subgroups in a population) of people who use drugs in Vancouver, Canada, and examined how these classes relate to phylogenetic clustering of hepatitis C virus (HCV) infection. HCV antibody-positive people who use drugs from two cohorts in Vancouver, Canada (1996-2012), with a Core-E2 sequence were included. Time-stamped phylogenetic trees were inferred, and phylogenetic clustering was determined by time to most common recent ancestor. Latent classes were estimated, and the association with the phylogenetic clustering outcome was assessed using an inclusive classify/analyse approach. Among 699 HCV RNA-positive participants (26% female, 24% HIV+), recent drug use included injecting cocaine (80%), injecting heroin (70%), injecting cocaine/heroin (ie, speedball, 38%) and crack cocaine smoking (28%). Latent class analysis identified four distinct subgroups of drug use typologies: (i) cocaine injecting, (ii) opioid and cocaine injecting, (iii) crack cocaine smoking and (iv) heroin injecting and currently receiving opioid substitution therapy. After adjusting for age and HIV infection, compared to the group defined by heroin injecting and currently receiving opioid substitution therapy, the odds of phylogenetic cluster membership was greater in the cocaine injecting group (adjusted OR [aOR]: 3.06; 95% CI: 1.73, 5.42) and lower in the crack cocaine smoking group (aOR: 0.06; 95% CI: 0.01, 0.48). Combining latent class and phylogenetic clustering analyses provides novel insights into the complex dynamics of HCV transmission. Incorporating differing risk profiles associated with drug use may provide opportunities to further optimize and target HCV treatment and prevention strategies.

Rural and urban comparisons of polysubstance use profiles and associated injection behaviors among people who inject drugs in Puerto Rico

INTRODUCTION

In contrast to urban populations, little is known about polysubstance use among rural people who inject drugs (PWID), particularly in Puerto Rico where injection drug use and related health consequences are prevalent. The aim of the study is to compare injection and non-injection substance use profiles among separate urban and rural samples of Puerto Rican PWID.

MATERIAL AND METHODS

Data for the urban sample come from 455 PWID who participated in the CDC's National HIV Behavioral Surveillance survey of injection drug use in San Juan. The data for the rural sample come from 315 PWID residing in four rural cities approximately 40-miles from San Juan. Latent class analysis was used to derive separate urban and rural profiles of weekly injection and non-injection substance use. Injection behaviors were examined as possible correlates of latent class membership.

RESULTS

Five latent classes were identified in the urban sample, and three latent classes were identified in the rural sample. Classes were similar across samples; however, key differences emerged. Both samples had classes of primary heroin injectors, primary speedball injectors, and cocaine-heroin injectors. The urban sample had one high polysubstance class. Polysubstance use profiles that shared similar characteristics between samples also shared similar injection patterns, with some variation.

DISCUSSION

Variations in substance use patterns and associated health risks are likely shaped by social and geographic boundaries.

CONCLUSIONS

Understanding variations in substance use patterns across rural and urban locales may improve surveillance efforts and tailor desistance and harm reduction efforts at the state and local levels.

Prevalence and Correlates of Heroin-Methamphetamine Co-Injection Among Persons Who Inject Drugs in San Diego, California, and Tijuana, Baja California, Mexico

OBJECTIVE

Although persons who inject drugs (PWID) in the western United States-Mexico border region are known to inject both heroin and methamphetamine, little is known about the prevalence and risks associated with co-injection of this depressant-stimulant combination (also known as "goofball" and "Mexican speedball").

METHOD

Baseline data from parallel cohort studies of PWID conducted concurrently in San Diego, CA, and Tijuana, Mexico, were used to estimate the prevalence and identify correlates of heroin-methamphetamine co-injection. PWID older than 18 years of age who reported injecting illicit drugs in the past month (N = 1,311; 32.7% female) were recruited in San Diego (n = 576) and Tijuana (n = 735) and completed interviewer-administered questionnaires. Bivariate and multivariable logistic regression analyses were used to identify correlates of heroin-meth-amphetamine co-injection.

RESULTS

The prevalence of co-injection in the past 6 months was 39.9% overall and was higher in Tijuana (55.8%) than in San Diego (19.8%). In multivariable analyses adjusting for study cohort, distributive syringe sharing, purchasing syringes prefilled with drugs, finding it hard to get new syringes, reporting great or urgent need for treatment, and younger age were independently associated with co-injection. Past-6-month overdose was significantly associated with higher odds of co-injection in San Diego than in Tijuana.

CONCLUSIONS

These findings indicate that heroin-methamphetamine co-injection is more common in Tijuana than in San Diego, yet this practice was only associated with overdose in San Diego. Heroin-methamphetamine coinjection was also independently associated with HIV-associated injection risk behaviors. Overdose-prevention interventions should address co-injection of depressants and stimulants.

Heroin and Methamphetamine Injection: An Emerging Drug Use Pattern

OBJECTIVE

We sought to describe an emerging drug use pattern characterized by injection of both methamphetamine and heroin. We examined differences in drug injection patterns by demographics, injection behaviors, HIV and HCV status, and overdose.

METHODS

Persons who inject drugs (PWID) were recruited as part of the National HIV Behavioral Surveillance (NHBS) system in Denver, Colorado. We used chi-square statistics to assess differences between those who reported only heroin injection, only methamphetamine injection, and combined heroin and methamphetamine injection. We used generalized linear models to estimate unadjusted and adjusted prevalence ratios to describe the association between drug injection pattern and reported nonfatal overdose in 2015. We also examined changes in the drug reported as most frequently injected across previous NHBS cycles from 2005, 2009, and 2012.

RESULTS

Of 592 participants who completed the survey in 2015, 173 (29.2%) reported only injecting heroin, 123 (20.8%) reported only injecting methamphetamine, and 296 (50.0%) reported injecting both drugs during the past 12 months. Injecting both heroin and methamphetamine was associated with a 2.8 (95% confidence interval: 1.7, 4.5) fold increase in reported overdose in the past 12 months compared with only injecting heroin. The proportion of those reporting methamphetamine as the most frequently injected drug increased from 2.1% in 2005 to 29.6% in 2015 (p < 0.001).

CONCLUSIONS

The rapid increase in methamphetamine injection, and the emergence of combining methamphetamine with heroin, may have serious public health implications.

A Hazard Analysis of Risk Factors of Mortality in Individuals Who Inject Drugs in Denver CO

Despite multiple risk factors for mortality among People Who Inject Drugs (PWID), more research is warranted that examines sub-populations within PWID. Mortality data from PWID participating in longitudinal HIV prevention research in Denver were obtained from The Colorado Department of Public Health and Environment. Risk factors for both all-cause and acute-toxicity related mortality were analyzed using Cox proportional hazards regression. Two-thousand seven individuals were interviewed at baseline. Eighty-six individuals died during the time frame of the study, 58 of which were due to acute-toxicity. Disabled (HR = 3.3, p < 0.001), gay/lesbian-identified (HR = 2.6, p = 0.03), white race/ethnicity (HR = 2.4, p = 0.003), and use of a shared cooker (HR = 2.1, p = 0.01) were important adjusted risk factors. These suggest that drug and HIV interventions should utilize techniques that can address the needs of marginalized populations in addition to HIV drug risk behaviors.

Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico

INTRODUCTION AND AIMS

Patterns of polydrug use among people who inject drugs (PWID) may be differentially associated with overdose and unique human immunodeficiency virus (HIV) risk factors. Subgroups of PWID in Tijuana, Mexico, were identified based on substances used, route of administration, frequency of use and co-injection indicators.

DESIGN AND METHODS

Participants were PWID residing in Tijuana age ≥18 years sampled from 2011 to 2012 who reported injecting an illicit substance in the past month (n = 735). Latent class analysis identified discrete classes of polydrug use characterised by 11 indicators of past 6 months substance use. Multinomial logistic regression examined class membership association with HIV risk behaviours, overdose and other covariates using an automated three-step procedure in mplus to account for classification error.

RESULTS

Participants were classified into five subgroups. Two polydrug and polyroute classes were defined by use of multiple substances through several routes of administration and were primarily distinguished from each other by cocaine use (class 1: 5%) or no cocaine use (class 2: 29%). The other classes consisted primarily of injectors: cocaine, methamphetamine and heroin injection (class 3: 4%); methamphetamine and heroin injection (class 4: 10%); and heroin injection (class 5: 52%). Compared with the heroin-only injection class, memberships in the two polydrug and polyroute use classes were independently associated with both HIV injection and sexual risk behaviours.

DISCUSSION AND CONCLUSIONS

Substance use patterns among PWID in Tijuana are highly heterogeneous, and polydrug and polyroute users are a high-risk subgroup who may require more tailored prevention and treatment interventions. [Meacham MC, Roesch SC, Strathdee SA, Lindsay S, Gonzalez-Zuniga P, Gaines TL. Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico. Drug Alcohol Rev 2018;37:128-136].

A socio-structural approach to preventing injection drug use initiation: rationale for the PRIMER study

BACKGROUND

Injection drug use remains a primary driver of HIV and HCV-related harms globally. However, there is a gap in efforts to prevent individuals from transitioning into injecting. People who inject drugs (PWID) play a key role in the transition of others into injecting, and while behavioral interventions have been developed to address this phenomenon, socio-structural approaches remain unexplored. To that end, we hypothesize that certain interventions designed to reduce injecting-related risk behaviors may also reduce the risk that PWID expose and introduce others into injecting. Identifying the preventive potential of existing interventions will inform broader efforts to prevent injecting and related harms.

METHODS

The Preventing Injecting by Modifying Existing Responses (PRIMER) study is a multi-country mixed methods study with an aim to investigate whether specific interventions (e.g., opioid substitution therapy, supervised injection facilities, stable housing, incarceration environments) and related factors (e.g., public injecting and gender) influence the likelihood that PWID initiate others into injecting. This study will (1) investigate the PWID participation in injection initiation; (2) identify factors influencing the risk that PWID expose others to or facilitate injection initiation; (3) describe drug scene roles that increase the risk of PWID facilitating injection initiation; and (4) evaluate the impact of structural, social, or biomedical interventions on the risk that PWID facilitate injection initiation. It does so by pooling observational data from cohort studies of PWID in six cities: Vancouver, Canada; San Diego, USA; Tijuana, Mexico; Paris, Marseille, and Bordeaux, France.

RESULTS

Team members are conducting a prospective, multi-site study of PWID (n = 3050) in North America and France that includes quantitative and qualitative data collection through four separate cohort studies of PWID (San Diego, STAHR II; Tijuana, El Cuete IV; Vancouver, V-DUS; Bordeaux, Marseille, Paris and Strasbourg, COSINUS).

CONCLUSIONS

PRIMER is the largest study of injection initiation to date and the first to investigate structural approaches to preventing injection drug use initiation. Findings have the potential to inform the development and scale up of new and existing interventions to prevent transitions into injecting.

TRIAL REGISTRATION

Preventing Injecting by Modifying Existing Responses (PRIMER), NIDA DP2-DA040256-01 .

Factors associated with patterns of mobile technology use among persons who inject drugs

BACKGROUND

New and innovative methods of delivering interventions are needed to further reduce risky behaviors and increase overall health among persons who inject drugs (PWID). Mobile health (mHealth) interventions have potential for reaching PWID; however, little is known about mobile technology use (MTU) in this population. In this study, the authors identify patterns of MTU and identified factors associated with MTU among a cohort of PWID.

METHODS

Data were collected through a longitudinal cohort study examining drug use, risk behaviors, and health status among PWID in San Diego, California. Latent class analysis (LCA) was used to define patterns of MTU (i.e., making voice calls, text messaging, and mobile Internet access). Multinomial logistic regression was then used to identify demographic characteristics, risk behaviors, and health indicators associated with mobile technology use class.

RESULTS

In LCA, a 4-class solution fit the data best. Class 1 was defined by low MTU (22%, n = 100); class 2, by PWID who accessed the Internet using a mobile device but did not use voice or text messaging (20%, n = 95); class 3, by primarily voice, text, and connected Internet use (17%, n = 91); and class 4, by high MTU (41%, n = 175). Compared with low MTU, high MTU class members were more likely to be younger, have higher socioeconomic status, sell drugs, and inject methamphetamine daily.

CONCLUSION

The majority of PWID in San Diego use mobile technology for voice, text, and/or Internet access, indicating that rapid uptake of mHealth interventions may be possible in this population. However, low ownership and use of mobile technology among older and/or homeless individuals will need to be considered when implementing mHealth interventions among PWID.

A typology of people who tamper with pharmaceutical opioids: responses to introduction of a tamper-resistant formulation of controlled-release oxycodone

PURPOSE

In April 2014, a tamper-resistant controlled-release oxycodone formulation was released in Australia. We aimed to determine whether there are latent classes of people who tamper with pharmaceutical opioids based on frequency of opioid and illicit drug use, the demographic and clinical profiles of these groups, and if there were changes in use and harms following the introduction.

METHODS

A prospective cohort of 606 people who regularly tamper with pharmaceutical opioids was interviewed January to March 2014 (Wave 1) and May to August 2014 (Wave 2). Latent class analysis identified groups based on non-prescribed opioid, illicit drug and prescribed opioid substitution therapy (OST) use at Wave 1. Regression models examined whether group membership predicted use and harms at Wave 2.

RESULTS

Four groups were identified: frequent OST group (39%), mixed OST/heroin group (7%), infrequent pharmaceutical opioid and heroin group (44%) and frequent oxycodone group (25%). Compared with the frequent OST group, the infrequent pharmaceutical opioid/heroin group was more likely to report non-everyday pain and risky alcohol use, and the frequent oxycodone group had higher odds of homelessness. At Wave 2, oxycodone use decreased across groups (odds ratios (OR) ≤ 0.18, p < 0.001, particularly for the frequent oxycodone group: OR ≤ 0.05, p < 0.001), with reductions in days of use (g ≥ 0.35, p < 0.050). Non-prescribed pharmaceutical opioid use, illicit drug use and harms remained stable or decreased.

CONCLUSIONS

Despite heterogeneity among people who tamper with pharmaceutical opioids, the tamper-resistant formulation was followed by reductions in oxycodone tampering among high-frequency and low-frequency users. There was no evidence of increased use of other opioids or illicit drugs.

Benzodiazepine use as an independent risk factor for HIV infection in a Canadian setting

BACKGROUND

Although the harms of prescription drug diversion are of growing international concern, the potential impact of prescription drug use on HIV infection has not been well assessed. We evaluated whether benzodiazepine use was associated with HIV seroconversion among a cohort of persons who inject drugs (PWID) in a Canadian setting.

METHODS

Between May, 1996 and November, 2013, data were derived through a prospective cohort study of PWID in Vancouver, Canada. A total of 1682 baseline HIV negative participants were followed for a median of 79.5 months (interquartile range: 32.1-119.1), among whom 501 (29.8%) reported benzodiazepine use at baseline, and 176 seroconverted during follow-up, equal to an incidence density of 1.5 (95% Confidence Interval [CI]: 1.3-1.7) cases per 100 person-years. Poisson regression with time-dependent variables was used to assess whether benzodiazepine use was associated with the time to HIV seroconversion.

RESULTS

After adjustment for potential confounders, benzodiazepine use (Adjusted Rate Ratio: 1.50; 95% CI: 1.01-2.24) was independently associated with a higher rate of HIV seroconversion.

CONCLUSIONS

Benzodiazepine use was an independent risk factor for HIV seroconversion among PWID in this setting. Greater recognition of the safety concerns related to benzodiazepine medications including diversion are needed.