Latent class analysis of polysubstance use, sexual risk behaviors, and infectious disease among South African drug users

Ecological momentary assessment study of same-hour polysubstance use among people who use opioids and additional substances

BACKGROUND

Polysubstance use is a defining feature of the opioid overdose epidemic in the United States today. Most quantitative studies of polysubstance use rely on 30-day retrospective measures. Understanding how drugs are co-used in shorter (daily and hourly) timeframes enhances our understanding of polysubstance-related overdose risk.

METHODS

We used ecological momentary assessment (EMA) to assess polysubstance in community-based sample of people who use drugs in Oakland, CA (N = 117). Participants provided data on substance use three times daily over 28 days, using a smartphone app. We created binary variables of same-day and same-hour polysubstance use and estimated its prevalence with mixed-effects logistic regression models.

RESULTS

The response rate to thrice-daily prompts was 64.6 %. The prevalence of same-day polysubstance use on any given day was 0.77 (95 % CI 0.73, 0.82), and the prevalence of same-hour polysubstance use was 0.71 (95 % CI 0.66, 0.76). Defined as the combination of opioids with stimulants, opioids with alcohol, opioids with benzodiazepines, or more than one opioid in the same hour, the probability of risky polysubstance use on a given day was 0.59 (95 % CI 0.52, 0.65). Excluding methadone from a treatment program, the probability of risky polysubstance use on a given day was 0.51 (95 % CI 0.44, 0.58).

CONCLUSIONS

Our findings highlight the importance of targeted prevention efforts addressing the diverse substance combinations that increase overdose risk. It is crucial to develop and test substance use treatment and overdose prevention strategies that address the complexities of polysubstance use, in partnership with people who use drugs.

Major Depression in Comorbidity with Substance use Disorders: Patients' Features and Clinical-Neurobiological Rationale of Antidepressant Treatments

The frequent co-occurrence of major depressive disorder (MDD) and substance use disorders (SUDs) entails significant clinical challenges. Compared to patients with MDD alone, patients with MDD and SUD often show increased anhedonia, emotional blunting, and impaired cognitive function. These symptoms lead to an inability to control cravings, more substance use, increased relapse rates, and poor adherence to the treatment. This fosters a detrimental cycle leading to more severe depressive symptoms, functional impairment, and chronicity, culminating in heightened morbidity, mortality, and healthcare resource utilization. Data on antidepressant treatment of MDD-SUD patients are inconclusive and often conflicting because of a number of confounding factors in clinical trials or difficulty in dissecting the specific contributions of pharmacological versus psychological interventions in real-world studies. The patient's unique clinical features and specific SUD and MDD subtypes must be considered when choosing treatments. Ideally, drug treatment for MDD-SUD should act on both conditions and address core symptoms such as anhedonia, craving, and cognitive dysfunction while ensuring minimal emotional blunting, absence of drug interactions, and no addictive potential. This approach aims to address unmet needs and optimize the outcomes in a clinical population often underrepresented in treatment paradigms.

Soccer and Vocational Training are Ineffective Delivery Strategies to Prevent HIV and Substance Abuse by Young, South African Men: A Cluster Randomized Controlled Trial

HIV and substance abuse are common among young men, associated with a cluster of risk behaviors. Yet, most services addressing these challenges are delivered in setting underutilized by men and are often inconsistent with male identity. This cluster randomized controlled trial aimed to reduce multiple risk behaviors found among young men township areas on the outskirts of Cape Town, South Africa. Young men aged 18-29 years (N = 1193) across 27 neighborhoods were randomized by area to receive HIV-related skills training during either: (1) a 12-month soccer league (SL) intervention; (2) 6-month SL followed by 6 months of vocational training (VT) intervention (SL/VT, n = 9); or 3) a control condition (CC). Bayesian longitudinal mixture models were used to evaluate behaviors over time. Because we targeted multiple outcomes as our primary outcome, we analyzed if the number of significantly different outcomes between conditions exceeded chance for 13 measures over 18 months (with 83%, 76%, and 61% follow-up). Only if there were three significant benefits favoring the SL/VT over the SL would benefits be significant. Outcome measures included substance use, HIV-testing, protective sexual behaviors, violence, community engagement and mental health. Consistent participation in the SL was typically around 45% over time across conditions, however, only 17% of men completed SL/VT. There were no significant differences between conditions over time based on the number of study outcomes. These structural interventions were ineffective in addressing young men's substance abuse and risk for HIV.Clinical Trial Registration: This trial was prospectively registered on 24 November 2014 with ClinicalTrials.gov (NCT02358226).

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.

Utilizing Soccer for Delivery of HIV and Substance Use Prevention for Young South African Men: 6-Month Outcomes of a Cluster Randomized Controlled Trial

Young men in South Africa face the intersecting epidemics of HIV, substance use and endemic poverty. We tested the effectiveness of a behavioral intervention using soccer training to reduce the cluster of risks associated with HIV and substance use. This cluster randomized controlled trial was conducted with men aged 18-29 years old in 27 neighborhoods in the townships of Cape Town, South Africa. Neighborhoods were randomized to receive for 6 months either: (1) Soccer League (SL; n = 18 neighborhoods, n = 778 men) who attended soccer three times weekly (72 sessions; 94% uptake, 45.5% weekly attendance rate), combined with an HIV/substance use, cognitive-behavioral intervention; or (2) a Control Condition (CC; n = 9; 415 men) who received educational materials and referrals at 3 month intervals. The primary outcome was the number of significant changes in a cluster of outcomes including HIV-related risks, substance abuse, employment/income, mental health, violence, and community engagement. There was only one significant difference on the rapid diagnostic tests for mandrax at 6 months, an insufficient number of changes to indicate a successful intervention. A group-based behavioral intervention was ineffective in addressing multiple risk behaviors among at-risk young men, similar to the findings of several recent soccer-related interventions. Early adulthood may be too late to alter well-established patterns of risk behaviors.Clinical Trial Registration This trial was prospectively registered on 24 November 2014 with ClinicalTrials.gov NCT02358226.

Polysubstance Use Patterns Associated With HIV Disease Severity Among Those With Substance Use Disorders: A Latent Class Analysis

OBJECTIVE

Polysubstance use is common among people with HIV infection (PWH) and with substance use disorder (SUD), but its effects are understudied. We aimed to identify polysubstance use patterns over time and assess their associations with HIV disease severity.

METHOD

In 233 PWH with current or past SUD, latent class analysis identified polysubstance use patterns based on the Alcohol Use Disorders Identification Test-Consumption and past-30-day use of cannabis, cocaine, opioids, and tranquilizers at baseline. We categorized changes in use patterns and tested associations between those changes and CD4 count and HIV viral suppression at 12 months in linear and logistic regressions.

RESULTS

Three patterns were identified at baseline: 18% did not use any substance (NONE--a priori defined); 63% used mostly cannabis and alcohol (CA); and 19% used opioids along with other drugs, including cocaine, tranquilizers, cannabis, and alcohol (MULTI). At 12 months, 40% moved from a high to a lower substance use class (MULTI to CA, either to NONE) or remained as NONE, 43% were in CA both times and 17% increased (NONE to CA, either to MULTI) or remained as MULTI. The adjusted mean CD4 count (for baseline covariates and baseline CD4 count) was significantly lower among participants increasing or remaining in MULTI (523, 95% CI [448, 598], cells/mm3) compared with those who decreased/abstained throughout (607, 95% CI [552, 663], p = .02). No significant difference was observed for HIV viral suppression.

CONCLUSIONS

We identified distinct polysubstance use patterns among PWH with SUD: cannabis/alcohol and opioids with alcohol and other drugs. Changes over time toward fewer substances/no use were associated with lower HIV disease severity based on CD4 count but not based on HIV viral suppression.

Resilience profiles predict polysubstance use in adolescents with a history of childhood maltreatment

Background

Childhood maltreatment (CM) can be an impediment to normative development and consistently predicts increased risk for substance misuse and polysubstance use (polySU). Yet, a subset of individuals who experience CM exhibit successful adaptations across the lifespan. Although there is an expansive literature on socioemotional and cognitive protective factors that mitigate impacts of CM, less is known about other, intra-individual resilience-promoting factors (e.g., positive future orientation) known to assuage high-risk SU patterns during adolescence.

Method

This study examined heterogeneity in individual-level resilience characteristics in maltreated youth as it related to CM characteristics and SU patterns during adolescence. Participants included maltreated youth from the longitudinal LONGSCAN sample (N=355; 181 females). Latent Profile Analysis was used to identify subgroups of CM-exposed individuals based on 5 resilience indicator variables (i.e., commitment to goals, engaging in demanding activities, self-reliance, positive future orientation, and externalizing behaviors). Tests for differences in SU patterns and CM characteristics between the resultant profiles were performed.

Results

Data models revealed 3 latent profiles based on participants' resilience traits (i.e., Low Resilience, Average Resilience, and High Resilience). There were no profile differences on the basis of CM characteristics. Those in the High Resilience profile were less likely to engage in polySU compared to the Average Resilience profile.

Implications

These findings highlight the promise of individual-level resilience factors that are not necessarily dependent upon caregiver or environmental inputs as protective against polySU following CM. This work represents a promising avenue for future preventative intervention efforts targeting emergent SU behaviors in high-risk youth.

Risk Behaviors Associated with Patterns of Sexualized Stimulant and Alcohol Use among Men Who Have Sex with Men: a Latent Class Analysis

Substance use during sexual encounters (sexualized substance use) is an important driver of HIV and sexually transmitted infection (STI) disparities that are experienced by men who have sex with men (MSM). This analysis aimed to identify patterns of sexualized substance use and their associations with HIV risk behaviors. We utilized visit-level data from a longitudinal cohort of predominantly Black/Latinx MSM, half with HIV and half with substance use in Los Angeles, California. Every 6 months from 8/2014 to 3/2020, participants underwent STI testing and completed surveys on demographics, sexualized substance use (stimulant and/or alcohol intoxication during oral sex, receptive anal intercourse [RAI] and/or insertive anal intercourse [IAI]), transactional sex, biomedical HIV prevention (pre-/post-exposure prophylaxis use or undetectable viral load), and depressive symptoms. Latent class analysis was used to identify patterns of sexualized substance use. Multinomial logit models evaluated risk behaviors associated with latent classes. Among 2386 study visits from 540 participants, 5 classes were identified: no substance use, sexualized stimulant use, sexualized alcohol use, sexualized stimulant and alcohol use, and stimulant/alcohol use during oral sex and RAI. Compared to the no sexualized substance use class, sexualized stimulant use was associated with transactional sex, current diagnosis of STIs, not using HIV biomedical prevention, and depressive symptoms. Sexualized alcohol use had fewer associations with HIV risk behaviors. Patterns of sexual activities, and the substances that are used during those activities, confer different risk behavior profiles for HIV/STI transmission and demonstrate the potential utility of interventions that combine substance use treatment with HIV prevention.

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.

Prevalence and Sociodemographic Determinants of Substance Use in Turkey

BACKGROUND

Substance use disorder is a serious public health problem. It is essential to know who is prone to substance use in order to adopt appropriate measures.

OBJECTIVES

This study aims to determine the use prevalence ratios of substance use (tobacco, alcohol, cannabis, cocaine, synthetic cannabinoids, ecstasy, and others) in a large-scale sample of a general population. It also intends to examine related sociodemographic factors.

METHODS

This study is based on a cross-sectional survey conducted with a nationally representative sample of 24,494 individuals in face-to-face interviews conducted by a trained team of 125 clinical psychologists.

RESULTS

Lifetime prevalence of single substance use and polysubstance use are 4.5 and 2.6%, respectively (nicotine and alcohol excluded). Age, gender, education level, and marital status are important sociodemographic determinants for other substance use. Similarly, smoking and alcohol consumption are important determinants for other substance use. The multinomial regression analysis results showed that compared with adults aged 39 years and older, early-emerging adults (aged 18-23 years), late-emerging adults (aged 24-29 years), and young adults (aged 30-39 years) are more likely to turn to single substance use and polysubstance use.

CONCLUSION

Tobacco, alcohol, and other substance use are serious health concerns in Turkey. Sociodemographic status is an important determinant of several aspects of tobacco, alcohol, and other substance use and, therefore, should be examined thoroughly to be able to develop effective protective and preventive strategies.

Risk factors associated with infection of blood-borne virus among people who used methamphetamine

BACKGROUND

The surge of methamphetamine use has been a complicating factor compounding the steeply increasing number of drug overdose deaths in the U.S. Infection from blood-borne viruses including hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV, related to methamphetamine use continue to grow. This study aims to examine the risk factors associated with HBV, HCV and HIV among people who used methamphetamine.

METHODS

People who ever used methamphetamine were identified from five National Health and Nutrition Examination Survey (NHANES) cohorts, 2007 to 2016. The outcome was either positive or negative for blood-borne viruses as identified from laboratory tests. Weighted statistics for the combined ten years of data were calculated by multiplying the weighted variable for laboratory measurements by 0.2. We examined the association of sexual activities (sexual partners, sexual identity), drug use behaviors (poly-drug use, injection drug use, frequency of drug use, age started using methamphetamine), demographics, and socio-economic status with blood-borne viruses using bivariate and multivariable logistic regression models.

RESULTS

There were 1132 participants representing approximately 11,996,319 persons who ever used methamphetamine in the U.S. Blood-borne viruses' positive rate was 13.0 per 100,000. Multivariable logistic regression analyses showed significant associations of blood-borne infections with age 40-49 years (vs. age 20-29 years, adjusted odds ratio 4.77, 95% CI 1.11-20.55), age 50-59 years (vs. age 20-29 years, 10.25, 2.40-43.82), living within poverty index 1-1.9 (vs. poverty index > = 2, 2.55; 1.19-5.49), living below the poverty threshold (vs. poverty index > = 2, 2.55; 1.11-5.86), having lower than high school education (vs. equal or higher than high school education, 3.13; 1.51-6.46), sexual identity as other than heterosexual (vs. heterosexual, 5.60; 1.72-18.28), using methamphetamine and heroin and cocaine (vs. using methamphetamine alone, 4.24; 1.06-16.92), injection drug use (vs. no injection drug use, 3.15; 1.61-6.16), and started using methamphetamine at age above 25 (vs. started using methamphetamine at age between 10 and 17, 2.09; 1.01-4.35).

CONCLUSIONS

Among people who use methamphetamine, those who use polysubstance, or who inject substances, are in urgent need for vaccination and interventions to avoid further harm from blood borne infections.

Examining risk behavior and syringe coverage among people who inject drugs accessing a syringe services program: A latent class analysis

INTRODUCTION

Injection drug use (IDU) remains a significant public health problem. IDU has been associated closely with the opioid crisis; driving overdose, HIV, and Hepatitis C (HCV) infection nationwide. Syringe services programs (SSPs) remain pivotal evidence-based interventions to reduce harm and engage subgroups of people who inject drugs (PWID). This study aims to provide policy considerations from the IDEA SSP, the first legal SSP in the state of Florida.

METHODS

We performed a latent class analysis on patterns of substance use among participants (N = 982) newly enrolled in a syringe services program (SSP). Associations between classes of substance use and sociodemographic variables, risky injection and sex behaviors, HIV/HCV status and syringe coverage were analyzed using the R3STEP and BCH 3-step procedures in latent class regression.

RESULTS

We found a three-class solution: Heroin-Dominant class (73.9%), Methamphetamine-Dominant class (9.5%) and Heroin/Cocaine class (16.6%). Compared to Heroin-Dominant class, the Heroin/Cocaine class were more likely to report homelessness, sharing works, unprotected sex, public injection, and to be HCV positive. Compared to both Heroin-Dominant and Heroin/Cocaine classes, the Methamphetamine-Dominant class were more likely to be male, Hispanic, gay or bisexual orientation, HIV positive, to report unprotected sex and sex with PWID. In addition, the lowest and highest syringe coverage were among those in the Heroin/Cocaine and Methamphetamine-Dominant classes, respectively.

CONCLUSION

Existing interventions among this population to mitigate infectious disease risk, such as SSPs, can be a used to engage differing PWID populations. However, multi-component, targeted preventive interventions and need-based syringe distribution policies are required to further reduce HIV and HCV risk among various PWID populations.

Trends of poly-substance use among Canadian youth

INTRODUCTION

Poly-substance use, increasingly understood as a behaviour with uniquely adverse consequences, is on the rise among Canadian youth. High levels of e-cigarette vaping and the recent legalization of recreational cannabis use may result in an acceleration of this trend. The aim of this work was to characterise changes in youth poly-substance use over time, generate baseline data for future investigations, and highlight areas of interest for policy action.

METHODS

Descriptive statistics and regression models explored patterns and trends in concurrent use of multiple substances (alcohol, cigarettes, cannabis, and e-cigarettes) among Canadian high school students taking part in the COMPASS prospective cohort study during Y2 (2013/2014; n = 45,298), Y3 (2014/2015, n = 42,355), Y4 (2015/2016; n = 40,436), Y5 (2016/2017; n = 37,060), and Y6 (2017/2018; n = 34,879).

RESULTS

Poly-substance use increased significantly over time, with over 50% of students who used substance reporting past-year use of multiple substances by 2017/2018. Male and Indigenous students were significantly more likely to report poly-substance use than female and white students respectively. E-cigarette vaping doubled from Y5 to Y6 and was included in all increasingly prevalent substance use combinations.

CONCLUSIONS

Youth poly-substance use, rising since 2012/2013, saw a particularly steep increase after 2016/2017. Differential effects were observed for distinct demographic subpopulations, indicating tailored interventions may be required. E-cigarette vaping surged in parallel with the observed increase, suggesting a key role for this behaviour in shaping youth poly-substance use.

Types of Polydrug Use Among Spanish Students in Health Sciences

Polydrug use among university students may be a predictor for established patterns of multiple substance use and potentially entail long-term health problems. This study examined the types of polydrug use among Spanish students in health sciences. Undergraduate students (n = 968), aged 18-38 years (M = 21.09 years, SD = 4.10), completed the survey. A percentage of 44.3% of the participants were classified as polydrug users. Type A users (alcohol and cigarettes) made up 17.8% of the participants surveyed, whereas 20.1% were Type B (cannabis with cigarettes and/or alcohol), and a further 5.7% were Type C (cannabis with cigarettes and/or alcohol, plus at least another kind of illegal drug). Type A was the most common type among women, whereas Type C was the most common among men. Type B use was higher among women 18-19 years old than among women 25-29 years old, whereas there were no female Type C users younger than 20 years old. Weekend consumption was higher, than weekday consumption, across all polydrug user types and substances. These results suggest that the prevalence of polydrug use among Spanish students in health sciences was similar to students in other disciplines, with Type B as the most prevalent among healthcare and nonhealthcare students. Taking into account the differences based on gender, age, and time of consumption, a specific approach to the different typologies of polydrug users might be a vital step in the successful development of preventive interventions tailored to the changing reality of psychoactive substance use.

Patterns of Polysubstance Use Among Non-Hispanic White and American Indian/Alaska Native Adolescents: An Exploratory Analysis

INTRODUCTION

The prevalence of polysubstance use is well described, but less is known about correlates and patterns of polysubstance use. Previous research characterized latent subgroups of substance users by the type substance used. Racial disparities in the prevalence of polysubstance use exist, particularly for American Indian/Alaska Native (AI/AN) populations. The objective of our study was to describe differences in patterns of polysubstance use between non-Hispanic white and AI/AN adolescents.

METHODS

We obtained data from the 2013 Youth Risk Behavior Survey (YRBS). We analyzed substance use patterns (cigarettes, alcohol, marijuana, cocaine, inhalants, heroin, methamphetamines, ecstasy, steroids, and injected drugs) separately among 375 AI/AN and 15,633 non-Hispanic white adolescents. We calculated pairwise correlations. Exploratory factor analysis identified latent factors of polysubstance use patterns.

RESULTS

The use of all substances by AI/AN adolescents was the same or higher than use by non-Hispanic white adolescents, particularly for cocaine, heroin, and steroids. We found strong correlations between use of heroin and injected drugs and between use of cocaine and ecstasy among both populations. We found a latent factor for cigarettes, alcohol, and marijuana and another factor for broad polysubstance use among both populations. We found a factor for steroids and injected drugs among AI/AN adolescents, a factor for cocaine and ecstasy among non-Hispanic white adolescents, and a unique factor for methamphetamines.

CONCLUSION

Differences in substance use patterns exist between AI/AN and non-Hispanic white adolescents, particularly for illegal drug use. If validated in future research, information on these differences could be used to inform tailored intervention programs aimed at preventing substance use.

A latent class analysis of the past-30-day substance use patterns among lifetime cocaine users: Findings from a community sample in North Central Florida

Objectives

Cocaine use is increasing and many cocaine users engage in polysubstance use. Within polysubstance use, relationships among use of individual substances are necessarily complex. To address this complexity, we used latent class analysis (LCA) to identify patterns of polysubstance use among lifetime cocaine users and examine associations among these patterns, demographics, and risk profiles.

Methods

Members of HealthStreet, an ongoing community engagement program, were asked about lifetime and past 30-day use of cocaine, alcohol, tobacco, marijuana, and prescription medications, mental health conditions, recent Emergency Department (ED) visits and demographics. LCA was used to identify classes of past 30-day polysubstance use among individuals who endorsed lifetime cocaine use. Multinomial logistic regression identified factors associated with these classes.

Results

Among 1797 lifetime cocaine users, a five-class LCA model was identified: 1) past 30-day tobacco use only (45%), 2) past 30-day alcohol, marijuana and tobacco use (31%), 3) past 30-day tobacco, prescription opioid and sedative use (13%), 4) past 30-day cocaine, alcohol, marijuana and tobacco use (9%), 5) past 30-day cocaine and multiple polysubstance use (2%). Demographics, ED visits and mental health conditions were associated with class membership.

Conclusions

Approximately 11% of lifetime cocaine users used cocaine in the past 30 days with two different concurrent substance use patterns. Prescription medication (opioids and sedatives) and complex polysubstance use patterns were stronger indicators of negative outcomes than current cocaine use. Cocaine was not used frequently with other stimulants. In addition to polysubstance use, prescription medication use should be targeted for intervention among lifetime cocaine users.

Understanding HIV Risk Behaviors Among Young Men in South Africa: A Syndemic Approach

Young men in South Africa experience several adverse socio-structural and psychosocial factors that may contribute HIV risk behaviors. This study applied a syndemic framework to explore whether these syndemic factors are interconnected and work in synergy to increase HIV risk behaviors. Five syndemic factors were assessed including: binge drinking, polydrug use, depressive symptoms, violence and food insecurity on two HIV risk behaviors: multiple sex partners and transactional sex. Participants were (N = 1233) young men aged 18-29 years from a township in Cape Town, South Africa. Bivariate logistic regression analysis demonstrated that many of the syndemic factors were related to one another. Pairwise interactions (on an additive scale) among the syndemic factors revealed significant positive interactions between binge drinking and violence on greater odds of reporting multiple sex partners (aOR = 5.10, 95% CI 3.10, 8.29; p = < .001) compared to reporting neither factor. Also, food insecurity and violence (aOR = 2.89, 95% CI 1.63, 5.11; p = < .001) as well as food insecurity and polydrug use (aOR = 2.73, 95% CI 1.54, 4.84; p = < .001) were significantly associated with greater odds of transactional sex compared to reporting neither factor. Our findings highlight a synergistic relationship between some adverse socio-structural and psychosocial factors on HIV risk behaviors. HIV prevention programs that address multiple syndemic factors simultaneously may achieve greater impact on HIV risk reduction.

Differentially classified methamphetamine-using men who have sex with men: A latent class analysis

CONTEXT

Substance use interventions for methamphetamine-using men who have sex with men (MSM) are limited by the assumption that they are a uniform group. We hypothesized that an LCA would identify distinct patterns of substance use and demographic and psychosocial variables associated with different substance-using groups would aid in understanding distinctions. Using cross-sectional data from 343 methamphetamine-using MSM, we conducted an LCA to model the patterns of polysubstance use then examined how the classes varied on psychosocial variables defined by the Information-Motivation-Behavioral Skills (IMB) model.

FINDINGS

Because we were interested in identifying patterns of polysubstance use (PSU) among our sample, we identified four classes: minimal PSU, marijuana PSU, cocaine/hallucinogens PSU, and designer drugs/heroin PSU. Men in the marijuana PSU class were less likely to have positive attitudes towards methamphetamine than participants in the other three classes. Men in the Cocaine and Hallucinogens PSU class were more likely to have higher PANAS scores (OR = 13.00 [3.25, 52.07]) compared to the other classes, and they were more likely to have higher self-efficacy to enact safer substance use strategies (OR = 10.72 [3.23, 35.47]). MSM in the Designer Drug and Heroin PSU class were more likely to have a diagnosis of Hepatitis B (OR = 4.07 [0.86, 19.36] despite having higher knowledge of sexual health practices (OR = 0.55 [0.36, 0.84].

CONCLUSIONS

Differential classification for methamphetamine-using MSM suggests an opportunity for tailored interventions and secondary prevention programs. By understanding how men vary on illicit substance use, interventionists can routinely screen and link men before they potentially progress to another classification.

The Opioid Epidemic in Africa And Its Impact

Purpose of review

Opioid use disorder (OUD) is a global phenomenon and is on the rise in Africa, denoting a shift from historical patterns of drug transport to internal consumption. In contrast, opioids for clinical pain management in Africa remain among the least available globally. This region also has the highest HIV and HCV disease burden, and the greatest shortages of health workers and addiction treatment. We undertook a systematic review of the literature to describe opioid use in Africa and how it is being addressed.

Recent findings

A total of 84 articles from 2000 to 2018 were identified. Descriptions of country-specific populations and patterns of opioid misuse were common. A smaller number of articles described interventions to address OUD.

Summary

OUD occurs in sub-Saharan Africa, with attendant clinical and social costs. Evidence-based policies and health system resources are needed to promote OUD prevention and management, and infectious disease transmission reduction.

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.

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.

Polysubstance use profiles among electronic dance music party attendees in New York City and their relation to use of new psychoactive substances

BACKGROUND

Electronic Dance Music (EDM) party attendees are often polysubstance users and are at high risk for use of new psychoactive substances (NPS). We sought to identify patterns of use of common illegal drugs among EDM party attendees, sociodemographic correlates, and use of NPS as a function of patterns of use of more common drugs to inform prevention and harm reduction.

METHOD

Using time-space-sampling, 1045 individuals aged 18-40 were surveyed entering EDM parties in New York City. We queried past-year use of common illegal drugs and 98 NPS. We conducted latent class analysis to identify polysubstance use profiles of use of eight common drugs (i.e., ecstasy, ketamine, LSD, mushrooms, powder cocaine, marijuana, amphetamine, benzodiazepines). Relationships between drug classification membership and sociodemographics and use of drugs within six NPS categories were examined.

RESULTS

We identified four profiles of use of common drugs: non-polysubstance use (61.1%), extensive polysubstance use (19.2%), moderate polysubstance use/stimulants (12.8%), and moderate polysubstance use/psychedelics (6.7%). Those in the moderate/psychedelic group were at higher odds of using NPS with psychedelic-type effects (2C, tryptamines, and other "new" psychedelics; Ps<0.05). Extensive polysubstance users were at increased odds of reporting use of 2C drugs, synthetic cathinones ("bath salts"), tryptamines, other new (non-phenethylamine) psychedelics, new dissociatives, and synthetic cannabinoids (Ps<0.05).

CONCLUSION

NPS preference is linked to the profile of use of common drugs among individuals in the EDM scene. Most participants were identified as non-polysubstance users, but findings may help inform preventive and harm reduction interventions among those at risk in this scene.

Screening for Sexually Transmitted Infections in Adolescent Girls and Young Women in Mombasa, Kenya: Feasibility, Prevalence, and Correlates

INTRODUCTION

As adolescents and young women become sexually active, they are at risk of adverse reproductive health outcomes including sexually transmitted infections (STIs). We assessed feasibility and acceptability of STI screening among 15- to 24-year-old women in Mombasa, Kenya.

METHODS

After sensitization activities, participants were recruited from 3 high schools and 1 university. Study staff conducted informational sessions. Students interested in participating were given consent forms to take home, and invited to visit our clinic for STI screening. During clinic visits, participants completed a self-administered questionnaire and provided a urine specimen for STI testing using a nucleic acid amplification test.

RESULTS

Between August 2014 and March 2015, 463 high school and 165 university students collected consent forms. Of these, 293 (63%) from high schools versus 158 (95%) from university attended clinic for STI screening (P < 0.001). Of the 150 (33%) who reported any history of insertive vaginal sex, 78 (52.0%) reported condom use at the last sex act, 31 (20.7%) reported using modern nonbarrier contraceptive methods, and 37 (24.7%) reported not using any contraception at the last sex act. Twenty-six (5.8%) participants were diagnosed with STIs (7 [1.6%] Neisseria gonorrhoeae, 16 [3.6%] Chlamydia trachomatis, 3 [0.7%] Trichomonas vaginalis). In multivariable analyses, reporting receptive vaginal sex without a condom was associated with having a laboratory confirmed STI (odds ratio, 6.21; 95% confidence interval, 1.72-22.28).

CONCLUSIONS

These findings support the need for reproductive health interventions to reduce the risk of STIs in a population of adolescent girls and young women in East Africa.

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.

Health outcomes associated with crack-cocaine use: Systematic review and meta-analyses

BACKGROUND

Crack-cocaine use is prevalent largely in socio-economically marginalized populations in the Americas. Its use has been associated with diverse health outcomes, yet no recent or systematic reviews of these exist.

METHODS

A systematic review of health outcomes associated with crack-cocaine use was performed, using MEDLINE, Scopus, Web of Science, CINAHL, PsycINFO, and LILACS up to October 2016. Search terms included crack-cocaine and health outcome-related keywords, targeting peer-reviewed studies on quantified health outcomes associated with crack-cocaine use. Random effects meta-analyses produced pooled odds ratios. Levels of evidence for major results were assessed using the GRADE approach. A review protocol was registered with PROSPERO (CRD42016035486).

RESULTS

Of 4700 articles returned, 302 met eligibility criteria, reporting on health outcomes for 14 of 22 ICD-10 chapters. Conclusive evidence and meta-analyses showed positive associations between crack-cocaine use and blood/sexually transmitted diseases (HIV and hepatitis C virus, others); moderate evidence and meta-analyses supported associations with neonatal health, and violence. There were mixed associations for mental and other health outcomes, yet insufficient evidence to perform meta-analyses for many categories (e.g., mortality). Most underlying research was of limited or poor quality, with crack-cocaine commonly assessed as a secondary covariate.

CONCLUSIONS

Crack-cocaine use was associated with a range of health outcomes, although it was unclear if there was direct causal impact, interactions between risk factors, or external drivers of both crack-cocaine use and outcomes. Rigorous epidemiological studies are needed to systematically assess health outcomes of crack-cocaine use and underlying pathways, also to inform evidence-based interventions.

Latent Class Analysis of HIV Risk Behaviors Among Russian Women at Risk for Alcohol-Exposed Pregnancies

The number of HIV cases attributed to heterosexual contact and the proportion of women among HIV positive individuals has increased worldwide. Russia is a country with the highest rates of newly diagnosed HIV infections in the region, and the infection spreads beyond traditional risk groups. While young women are affected disproportionately, knowledge of HIV risk behaviors in women in the general population remains limited. The objectives of this study were to identify patterns of behaviors that place women of childbearing age at high risk for HIV transmission and determine whether socio-demographic characteristics and alcohol use are predictive of the risk pattern. A total of 708 non-pregnant women, aged between 18 and 44 years, who were at risk for an alcohol-exposed pregnancy were enrolled in two regions in Russia. Participants completed a structured interview focused on HIV risk behaviors, including risky sexual behavior and alcohol and drug use. Latent class analysis was utilized to examine associations between HIV risk and other demographic and alcohol use characteristics and to identify patterns of risk among women. Three classes were identified. 34.93% of participants were at high risk, combining their risk behaviors, e.g., having multiple sexual partners, with high partner's risk associated with partner's drug use (class I). Despite reporting self-perceived risk for HIV/STI, this class of participants was unlikely to utilize adequate protection (i.e., condom use). The second high risk class included 13.19% of participants who combined their risky sexual behaviors, i.e., multiple sexual partners and having STDs, with partner's risk that included partner's imprisonment and partner's sex with other women (class II). Participants in this class were likely to utilize protection/condoms. Finally, 51.88% of participants were at lower risk, which was associated primarily with their partners' risk, and these participants utilized protection (class III). The odds of being in class I compared with class III were 3.3 (95% CI [1.06, 10.38]) times higher for those women who had Alcohol Use Disorders Identification Test scores ≥ 8 than those who had lower scores, and were 3.9 (95% CI [1.69, 8.97]) times higher for those who used alcohol before sex than those who did not. In addition, women who drank more days per week were 1.36 times more likely to be in class II than in class III. The study informs prevention by identifying specific population groups and targets for interventions. Alcohol use is a significant predictor and an overarching factor of HIV risk in women. Since at-risk drinking is common among young Russian women, alcohol risk reduction should be an essential component of HIV prevention efforts.

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].

Characteristic substance misuse profiles among youth entering an urban emergency department: neighborhood correlates and behavioral comorbidities

BACKGROUND

Little is known about characteristic profiles of substance use - and their individual- and neighborhood-level correlates - among high-risk youth.

OBJECTIVES

To identify characteristic substance misuse profiles among youth entering an urban emergency department (ED) and explore how those profiles relate to individual- and community-level factors.

METHODS

Individual-level measures came from screening surveys administered to youth aged 14-24 at an ED in Flint, Michigan (n = 878); alcohol outlet and crime data came from public sources. Binary misuse indicators were generated by using previously established cut-points on scores of alcohol and drug use severity. Latent class analysis (LCA) identified classes of substance use; univariate tests and multinomial models identified correlates of class membership.

RESULTS

Excluding non-misusers (51.5%), LCA identified three classes: marijuana-only (27.9%), alcohol/marijuana (16.1%), and multiple substances (polysubstance) (4.6%). Moving from non-misusers to polysubstance misusers, there was an increasing trend in rates of: unprotected sex, motor vehicle crash, serious violence, weapon aggression, and victimization (all p < .001). Controlling for individual-level variables, polysubstance misusers lived near more on-premises alcohol outlets than non-misusers (RRR = 1.42, p = .01) and marijuana-only misusers (RRR = 1.31, p = .03). Alcohol/marijuana misusers were more likely to live near high violent crime density areas than non-misusers (RRR = 1.83, p = .01), and were also more likely than marijuana-only misusers to live in areas of high drug crime density (RRR = 1.98, p = .03). No other relationships were significant.

CONCLUSION

Substance-misusing youth seeking ED care have higher risk for other problem behaviors and neighborhood-level features display potential for distinguishing between use classes. Additional research to elucidate at-risk sub-populations/locales has potential to improve interventions for substance misuse by incorporating geographic information.

Mostly Smokers: Identifying Subtypes of Emerging Adult Substance Users

BACKGROUND

The concurrent use of marijuana and other substances among emerging adults (ages 18-25) is a major public health problem. This study examined if there are distinct subtypes of emerging adult marijuana users and if these are associated with demographic and substance use variables.

METHODS

The design was a cross-sectional interview with a community sample of 1,503 emerging adults in the northeastern U.S. who reported last month marijuana use. We used latent class analysis (LCA) to identify distinct subtypes of emerging adults who used additional substances and examined predictors of the latent classes.

RESULTS

We identified three distinct classes of emerging adults who use substances: "mostly smokers" (those who primarily use marijuana and nicotine), "moderate users" (those who primarily use marijuana and/or heavy episodic alcohol), and "polysubstance users." Polysubstance users had higher probabilities of use of all assessed substances (e.g. cocaine, opiates, sleep medications, stimulants, synthetic marijuana, and inhalants) than the other two groups. Not being currently enrolled in school and male gender were associated with mostly smokers and polysubstance users group status.

CONCLUSIONS

We identified a distinct group of emerging adult marijuana users who primarily smoke marijuana and cigarettes, suggesting that there could be a shared vulnerability for risk of co-occurrence.

Gender Differences in the Association Between Religion/Spirituality and Simultaneous Polysubstance Use (SPU)

While religion/spirituality strongly protects against drug use (Cheney et al. in J Drug Issues 44(1):94-113, 2014), little is known about gender differences in the association of religion/spirituality on simultaneous polysubstance use (SPU) among those who use prescription opioids. Data come from a community-based study that recruited community members from the St Louis area (N = 632). Participants were asked whether they used prescription opioids when not prescribed for them or in ways other than prescribed in the past 12 months. Religion/spirituality was categorized as high, medium, or low based on personal views on the importance of religion and spirituality, attendance at religious services, and advice seeking from religious leaders. SPU was defined as non-medical use of opioids simultaneously with use of cocaine, alcohol, ecstasy, or marijuana. Multivariate logistic regression determined the association between religion/spirituality, demographic variables, and SPU. Men with high levels of religion/spirituality had 63 % decreased odds of SPU compared with men with low levels. Other variables associated with SPU in men were four or more arrests (AOR 2.21), multiple sex partners (AOR 2.11), and opioid use without a prescription (AOR 3.04). Women with high or medium levels of religion/spirituality had 58 and 62 % decreased odds of SPU compared with women with low levels. Variables that predicted SPU in women also included 4+ arrests (AOR 5.00) and never being married (AOR 2.13). Being African-American was associated with decreased odds of SPU in women (AOR 0.32). Overall, a high level of religion/spirituality was associated with lower odds of SPU. Gender differences in this association were evident, whereas women with even a medium level of religion/spirituality had significantly decreased odds of SPU. Future drug prevention and interventions should consider the relevance of religion/spirituality in SPU.

It is complicated: sexual partner characteristic profiles and sexually transmitted infection rates within a predominantly African American population in Mississippi

BACKGROUND

Mississippi has among the highest prevalence of sexually transmitted infections (STIs) in the United States. Understanding sexual networks can provide insight into risk factors for transmission and guide prevention interventions.

METHODS

Participants included 1437 primarily African American (95%) adults presenting for care at an STI clinic in Jackson, Mississippi. Latent class analysis identified underlying population subgroups with unique patterns of response on a comprehensive set of 14 sexual partner variables, such as living with or having a child with a partner, partner dependence and trust, 1-time sexual encounters, multiple main partners, substance use, sexual concurrency, and incarceration. Classes were compared on participant age, sex, sexual orientation, public assistance, lifetime partners, relationship status, and self-reported past-year STI.

RESULTS

Three classes emerged. Class 1 (n = 746) participants were less dependent on partners and less likely to live with or have a child with a partner. Class 2 participants (n = 427) endorsed multiple STI risk factors, including partner incarceration, 6 or more lifetime partners, sexual concurrency, 1-time sexual encounters, and substance use at last sex. Class 3 participants (n = 226) were more likely to be in dependent, committed relationships with children. Class 2 had a higher proportion of self-report past-year STIs (36.7%) compared with classes 1 (26.6%) and 3 (26.1%).

CONCLUSIONS

Certain partner factors such as incarceration, substance use, and concurrency may contribute to increased STI risk. Partner factors may be useful proxies for STI risks and could be useful questions to include in screening questionnaires in clinical settings.

The development of a new condom use expectancy scale for at-risk adults

RATIONALE

Engaging in risky sexual behavior increases transmission of HIV.

OBJECTIVE

The present study used previously elicited salient outcomes of condom use to examine the factor structure and test the predictive utility of a condom use expectancy scale.

METHODS

Participants were drug offenders from court ordered drug diversion programs in Southern California. The condom use expectancy scale consisted of three factors: positive condom outcome items, negative condom outcome items, and safe sex items.

RESULTS

The factor analysis confirmed the three-factor structure. Positive condom use expectancies were a significant predictor of both condom use and intentions to use condoms, and negative condom use expectancies predicted non-use of condoms.

CONCLUSION

Understanding conditions of condom use can aid public health researchers and practitioners to better identify those in need of HIV prevention and how to target those needs.

Opioid withdrawal, craving, and use during and after outpatient buprenorphine stabilization and taper: a discrete survival and growth mixture model

INTRODUCTION

Most patients relapse to opioids within one month of opioid agonist detoxification, making the antecedents and parallel processes of first use critical for investigation. Craving and withdrawal are often studied in relationship to opioid outcomes, and a novel analytic strategy applied to these two phenomena may indicate targeted intervention strategies.

METHODS

Specifically, this secondary data analysis of the Prescription Opioid Addiction Treatment Study used a discrete-time mixture analysis with time-to-first opioid use (survival) simultaneously predicted by craving and withdrawal growth trajectories. This analysis characterized heterogeneity among prescription opioid-dependent individuals (N=653) into latent classes (i.e., latent class analysis [LCA]) during and after buprenorphine/naloxone stabilization and taper.

RESULTS

A 4-latent class solution was selected for overall model fit and clinical parsimony. In order of shortest to longest time-to-first use, the 4 classes were characterized as 1) high craving and withdrawal, 2) intermediate craving and withdrawal, 3) high initial craving with low craving and withdrawal trajectories and 4) a low initial craving with low craving and withdrawal trajectories. Odds ratio calculations showed statistically significant differences in time-to-first use across classes.

CONCLUSIONS

Generally, participants with lower baseline levels and greater decreases in craving and withdrawal during stabilization combined with slower craving and withdrawal rebound during buprenorphine taper remained opioid-free longer. This exploratory work expanded on the importance of monitoring craving and withdrawal during buprenorphine induction, stabilization, and taper. Future research may allow individually tailored and timely interventions to be developed to extend time-to-first opioid use.

Correlates of Trichomonas vaginalis Among Middle Age and Older Adults Who Use Drugs

BACKGROUND

Recent studies have reported high rates of Trichomonas vaginalis among middle age and older adults. Though trichomoniasis risk factors in this age cohort remain largely unknown, illicit drug use has been associated with increased incidence of sexually transmitted infections (STIs). The number of mid-older adults using illicit drugs has increased significantly in recent years suggesting the need to understand the relationship between drug use and STIs in this age cohort.

OBJECTIVES

This study examined the relationship between drug use, sexual-risk behaviors, and biologically confirmed T. vaginalis in a sample of mid-older and younger adults who reported recent drug use.

METHODS

The cross-sectional design examined the relationship between past 6-month drug use, sexual risk-behaviors, and PCR-confirmed T. vaginalis in 264 adults age 18-64 who were recruited from Baltimore, Maryland. These relationships were also explored in the age-stratified sample among those 18-44 years ("younger") and individuals 45+ years ("mid-older").

RESULTS

Trichomoniasis prevalence did not differ significantly between younger (18.8%) and mid-older (19.1%) adults. Mid-older adults that tested positive for T. vaginalis were more likely to have used marijuana and crack in the past 6 months. Among younger adults, there were no associations between trichomoniasis and past 6-month drug use and sexual-risk behavior.

CONCLUSIONS/IMPORTANCE

Age- and drug-related immune decline is hypothesized to contribute to increase susceptibility to T. vaginalis in mid-older adults. Broad screening for trichomoniasis, particularly among older adults who are often not regarded as at risk for STIs, is needed to control this often asymptomatic infection.

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

BACKGROUND

Among persons who inject drugs (PWID), polydrug use (the practice of mixing multiple drugs/alcohol sequentially or simultaneously) increases risk for HIV transmission and unintentional overdose deaths. Research has shown local drug markets influence drug use practices. However, little is known about the impact of drug mixing in markets dominated by black tar heroin and methamphetamine, such as the western United States.

METHODS

Data were collected through an ongoing longitudinal study examining drug use, risk behavior, and health status among PWID. Latent class analysis (LCA) was used to identify patterns of substance use (heroin, methamphetamine, prescription drugs, alcohol, and marijuana) via multiple administration routes (injecting, smoking, and swallowing). Logistic regression was used to identify behaviors and health indicators associated with drug use class.

RESULTS

The sample included 511 mostly white (51.5%) males (73.8%), with mean age of 43.5 years. Two distinct classes of drug users predominated: methamphetamine by multiple routes (51%) and heroin by injection (49%). In multivariable logistic regression, class membership was associated with age, race, and housing status. PWID who were HIV-seropositive and reported prior sexually transmitted infections had increased odds of belonging to the methamphetamine class. Those who were HCV positive and reported previous opioid overdose had an increased odds of being in the primarily heroin injection class (all P-values < .05).

CONCLUSION

Risk behaviors and health outcomes differed between PWID who primarily inject heroin vs. those who use methamphetamine. The findings suggest that in a region where PWID mainly use black tar heroin or methamphetamine, interventions tailored to sub-populations of PWID could improve effectiveness.

Polysubstance use: diagnostic challenges, patterns of use and health

PURPOSE OF REVIEW

Polysubstance use is common, particularly amongst some age groups and subcultures. It is also associated with elevated risk of psychiatric and physical health problems. We review the recent research findings, comment on changes to polysubstance diagnoses, report on contemporary clinical and epidemiological polysubstance trends, and examine the efficacy of preventive and treatment approaches.

RECENT FINDINGS

Approaches to describing polysubstance use profiles are becoming more sophisticated. Models over the last 18 months that employ latent class analysis typically report a no use or limited-range cluster (alcohol, tobacco and marijuana), a moderate-range cluster (limited range and amphetamine derivatives), and an extended-range cluster (moderate range, and nonmedical use of prescription drugs and other illicit drugs). Prevalence rates vary as a function of the population surveyed. Wide-ranging polysubstance users carry higher risk of comorbid psychopathology, health problems, and deficits in cognitive functioning.

SUMMARY

Wide-ranging polysubstance use is more prevalent in subcultures such as 'ravers' (dance club attendees) and those already dependent on substances. Health risks are elevated in these groups. Research into the prevention and treatment of polysubstance use is underdeveloped. There may be benefit in targeting specific polysubstance use and risk profiles in prevention and clinical research.