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

Differences in hepatitis C virus (HCV) testing and treatment by opioid, stimulant, and polysubstance use among people who use drugs in rural U.S. communities

BACKGROUND

People who use drugs (PWUD) in rural communities increasingly use stimulants, such as methamphetamine and cocaine, with opioids. We examined differences in hepatitis C virus (HCV) testing and treatment history among rural PWUD with opioids, stimulants, and other substance use combinations.

METHODS

PWUD were enrolled from ten rural U.S. communities from 2018 to 2020. Participants self-reporting a positive HCV result were asked about their HCV treatment history and drug use history. Drug use was categorized as opioids alone, stimulants alone, both, or other drug(s) within the past 30 days. Prevalence ratios (PR) were yielded using adjusted multivariable log-binomial regression with generalized linear mixed models.

RESULTS

Of the 2,705 PWUD, most reported both opioid and stimulant use (74%); while stimulant-only (12%), opioid-only (11%), and other drug use (2%) were less common. Most (76%) reported receiving HCV testing. Compared to other drug use, those who reported opioid use alone had a lower prevalence of HCV testing (aPR = 0.80; 95% CI: 0.63, 1.02). Among participants (n = 944) who self-reported an HCV diagnosis in their lifetime, 111 (12%) ever took anti-HCV medication; those who used both opioids and stimulants were less likely to have taken anti-HCV medication compared with other drug(s) (aPR = 0.41; 95% CI: 0.19, 0.91).

CONCLUSIONS

In this pre-COVID study of U.S. rural PWUD, those who reported opioid use alone had a lower prevalence of reported HCV testing. Those diagnosed with HCV and reported both opioid and stimulant use were less likely to report ever taking anti-HCV medication.

Telehealth to increase healthcare access; perspectives of people who use drugs

BACKGROUND

People who use drugs (PWUD) often face restricted healthcare access despite their heightened healthcare needs. Factors such as stigma, mistrust of the healthcare system, competing priorities, and geographical barriers pose significant healthcare access challenges. Telehealth offers an innovative solution to expand healthcare access for better inclusion of underserved populations in healthcare. We aimed to explore PWUDs' perceptions of telehealth as a healthcare delivery modality.

METHODS

We utilized purposive sampling to recruit participants (N = 57) for nine focus group discussions (FGDs) in Athens, Greece. Eligibility criteria required participants to be at least 18 years, with current or prior injection drug use, and current internet access. The FGDs followed a semi-structured interview guide, were audio recorded, transcribed verbatim, translated into English, and de-identified. We applied thematic analysis to analyze FGD transcripts.

RESULTS

Participants' mean (standard deviation) age was 47.9 (8.9) years, 89.5% (51/57) were male, 91.2% (52/57) were of Greek origin, and 61.4% (35/57) had attended at least 10 years of school. Three main themes emerged from the FGDs: (1) high internet utilization for healthcare-related purposes among PWUD, (2) highlighting telehealth benefits despite access obstacles and PWUDs' concerns about diagnostic accuracy, and (3) approaches to overcome access obstacles and build digital trust. Participants extensively used the internet for healthcare-related processes, such as accessing healthcare information and scheduling provider appointments. Despite being telehealth-inexperienced, most participants expressed a strong willingness to embrace telehealth due to its perceived convenience, time-saving nature, and trusted digital environment. Some participants recognized that the inability to conduct physical examinations through telehealth reduces its diagnostic accuracy, while others expressed concerns about digital literacy and technological infrastructure accessibility. Most participants expressed a preference for video-based telehealth encounters over audio-only encounters. To build trust in telehealth and promote patient-centeredness, participants recommended an initial in-person visit, virtual eye contact during telehealth encounters, patient education, and partnerships with PWUD-supportive community organizations equipped with appropriate infrastructure.

CONCLUSIONS

PWUD frequently use the internet for health-related purposes and suggested several approaches to enhance virtual trust. Their insights and suggestions are practical guidance for policymakers seeking to enhance healthcare access for underserved populations through telehealth.

TRIAL REGISTRATION

NCT05794984.

Modeling the impact of a supervised consumption site on HIV and HCV transmission among people who inject drugs in three counties in California, USA

BACKGROUND

Supervised consumption sites (SCS) have been shown to reduce receptive syringe sharing among people who inject drugs (PWID) in the United States and elsewhere, which can prevent HIV and hepatitis C virus (HCV) transmission. PWID are at risk of disease transmission and may benefit from SCS, however legislation has yet to support their implementation. This study aims to determine the potential impact of SCS implementation on HIV and HCV incidence among PWID in three California counties.

METHODS

A dynamic HIV and HCV joint transmission model among PWID (sexual and injecting transmission of HIV, injecting transmission of HCV) was calibrated to epidemiological data for three counties: San Francisco, Los Angeles, and San Diego. The model incorporated HIV and HCV disease stages and HIV and HCV treatment. Based on United States data, we assumed access to SCS reduced receptive syringe sharing by a relative risk of 0.17 (95 % CI: 0.04-1.03). This model examined scaling-up SCS coverage from 0 % to 20 % of the PWID population within the respective counties and assessed its impact on HIV and HCV incidence rates after 10 years.

RESULTS

By increasing SCS from 0 % to 20 % coverage among PWID, 21.8 % (95 % CI: -1.2-32.9 %) of new HIV infections and 28.3 % (95 % CI: -2.0-34.5 %) of new HCV infections among PWID in San Francisco County, 17.7 % (95 % CI: -1.0-30.8 %) of new HIV infections and 29.8 % (95 % CI: -2.1-36.1 %) of new HCV infections in Los Angeles County, and 32.1 % (95 % CI: -2.8-41.5 %) of new HIV infections and 24.3 % (95 % CI: -1.6-29.0 %) of new HCV infections in San Diego County could be prevented over ten years.

CONCLUSION

Our models suggest that SCS is an important intervention to enable HCV elimination and could help end the HIV epidemic among PWID in California. It could also have additional benefits such facilitating pathways into drug treatment programs and preventing fatal overdose.

Sexually Transmitted Infection (STI) Incidence, STI Screening, and Human Immunodeficiency Virus Preexposure Prophylaxis Uptake in United States Veterans With Opioid Use Disorder in Long Island, New York

Background

Opioid use disorder (OUD) confers increased risk of contracting bloodborne and sexually transmitted infections (STIs). Limited data exist on infectious disease screening and preexposure prophylaxis (PrEP) usage among United States Veterans (USVs) with OUD, including persons who inject drugs (PWID). This study aimed to evaluate the epidemiology of human immunodeficiency virus (HIV), hepatitis C virus (HCV), bacterial STIs, and PrEP uptake in USVs with OUD, including PWID.

Methods

A retrospective chart review of USVs with OUD seeking care at Northport Veterans Affairs Medical Center between 2012 and 2022 was completed. Sociodemographics, HIV, HCV, STI testing rates and diagnosis, and PrEP uptake were compared between USVs, stratified by injection drug use history.

Results

We identified 502 USVs with OUD; 43% had a history of injection drug use. Overall, 2.2% of USVs had HIV and 28.7% had HCV. An STI was diagnosed in 10% of USVs, most frequently syphilis (1.8%). PWID were more likely to be tested for HIV (93.5% PWID vs. 73.1% non-PWID; P < .001), HCV (95.8% PWID vs. 80.8% non-PWID; P < .001), and syphilis (80% PWID vs. 69.2% non-PWID; P = .006). Total gonorrhea and chlamydia testing rates were 31.9% and 33.7%, respectively, without difference between the groups. PrEP was prescribed in 1.2% of USVs.

Conclusions

In USVs with OUD, gonorrhea and chlamydia screening occurred less frequently than syphilis, HCV, and HIV. PWID were more likely to be screened for HIV, HCV, and syphilis. PrEP uptake was low. Both PWID and non-PWID may benefit from increased STI screening and linkage to PrEP.

A cross-sectional assessment of injection of "salts" and HIV transmission-related behaviours among a cohort of people who inject drugs in Kyrgyzstan

INTRODUCTION

Despite the increasing availability of new psychoactive substances (hereafter referred to as "salts") in Eastern Europe and Central Asia, there is a dearth of epidemiological data on the relationship between injecting "salts" and HIV risk behaviours. This is particularly relevant in settings where injection drug use accounts for a substantial proportion of the HIV burden, such as in Kyrgyzstan, a former Soviet Republic. This study assessed whether injecting "salts" is associated with sexual and injection-related HIV risk behaviours among people who inject drugs in Kyrgyzstan.

METHODS

The Kyrgyzstan InterSectional Stigma Study is a cohort of people who inject drugs in Kyrgyzstan's capital of Bishkek and the surrounding rural administrative division of Chuy Oblast. We conducted a cross-sectional analysis using survey data collected from cohort participants between July and November 2021, which included information on injection drug use (including "salts") and HIV risk behaviours. To minimize confounding by measured covariates, we used inverse-probability-weighted logistic and Poisson regression models to estimate associations between recent "salt" injection and HIV risk behaviours.

RESULTS

Of 181 participants included in the analysis (80.7% men, 19.3% women), the mean age was 40.1 years (standard deviation [SD] = 8.8), and 22% (n = 39) reported that they had injected "salts" in the past 6 months. Among people who injected "salts," 72% (n = 28) were men, and most were ethnically Russian 59% (n = 23), with a mean age of 34.6 (SD = 9.6). Injecting "salts" was significantly associated with a greater number of injections per day (adjusted relative risk [aRR] = 1.59, 95% confidence interval [CI] = 1.30-1.95) but lower odds of using syringe service programmes in the past 6 months (adjusted odds ratio [aOR] = 0.20, 95% CI = 0.12-0.32). Injecting "salts" was also significantly associated with lower odds of condomless sex in the past 6 months (aOR = 0.42, 95% CI = 0.24-0.76) and greater odds of having ever heard of pre-exposure prophylaxis (aOR = 4.80, 95% CI = 2.61-8.83).

CONCLUSIONS

(PWID) people who inject drugs who inject "salts" are a potentially emergent group with increased HIV acquisition risk in Kyrgyzstan. Targeted outreach bundled with comprehensive harm reduction and pre-exposure prophylaxis services are needed to prevent transmission of HIV and other blood-borne viruses.

PrEP for people who use opioids: A NIDA clinical trials network survey study in Southern U.S. cities where HIV incidence is high

BACKGROUND

People who use opioids (PWUO) are at increased risk for HIV. Pre-exposure prophylaxis (PrEP) is effective but underutilized as HIV prevention among PWUO. This study examined predictors of willingness to take daily oral PrEP and long-acting injectable (LAI) PrEP among PWUO across eight Southern urban cities with high HIV incidence.

METHODS

HIV-negative PWUO (N = 308) seeking services in community-based programs participated in this cross-sectional survey study. Measures included demographics, sexual risk behavior, substance use frequency, and awareness of and willingness to take oral and injectable PrEP. Data were analyzed using mixed-effects models.

RESULTS

Willingness to take daily oral and LAI PrEP was moderately high (69.16% and 62.02%, respectively). Half had heard of PrEP, but only 4% had ever taken it. Only education and condomless vaginal sex predicted willingness to take oral PrEP. Only education predicted willingness to take LAI PrEP. Polysubstance use was prevalent, with substantial proportions of PWUO reporting frequent use of injection drugs (opioids or stimulants, 79.5%), non-injection opioids (73.3%), non-injection stimulants (71.1%), cannabis (62.6%), and hazardous drinking (29.6%). About 20% reported past-year condomless anal sex, and one-third reported past-year condomless vaginal sex.

CONCLUSIONS

PWUO in this study were amenable to PrEP, particularly in light of education and condomless vaginal sex. Careful consideration for matching PrEP messaging to the PWUO audience is needed. PrEP promotion should expand beyond men who have sex with men to include groups such as these predominantly heterosexual, polysubstance-using PWUO with HIV risk who were open to both formulations of PrEP.

Stimulant Drugs and Stimulant Use Disorder

The authors aim to summarize several key points of stimulant drugs and stimulant use disorder, including their indications, short-term and long-term adverse effects, current treatment strategies, and association with opioid medications. The global prevalence of stimulant use has seen annual increase in the last decade. Multiple studies have shown that stimulant use and stimulant use disorder are associated with a range of individual and public health issues. Stimulant misuse has led to a significant increase of overdose deaths in the United States.

High Seroprevalence of Hepatitis C Virus Among Cisgender Women Who Exchange Sex in the Seattle, Washington Area

BACKGROUND

Injection drug use (IDU) is a risk factor for hepatitis C virus (HCV) acquisition and occurs disproportionately among women who exchange sex (WES). However, little is known about HCV epidemiology in this population. We estimated HCV seroprevalence, identified correlates of HCV seropositivity, and characterized social networks by HCV serostatus and IDU history among WES in the Seattle, Washington, area.

METHODS

This was a secondary analysis of data from the 2016 National HIV Behavioral Surveillance survey in the Seattle, Washington area, a cross-sectional survey that used respondent-driven sampling (RDS) to enroll WES for money or drugs (N = 291). All participants were offered rapid HCV-antibody testing. We estimated HCV seropositivity and used log regression methods to estimate crude and adjusted prevalence ratios (PRs) for correlates of HCV seropositivity among WES. Using RDS recruitment chain data, we computed homophily indices to estimate the extent to which participants were likely to recruit another participant with the same HCV serostatus and IDU history.

RESULTS

In the study sample of WES in the Seattle, Washington area, 79% reported lifetime IDU and 60% were HCV seropositive. HCV seropositivity was strongly associated with ever injecting drugs (PRadj: 7.7 [3.3, 18.0]). The RDS homophily scores for HCV seropositivity (0.07) and ever injecting drugs (0.02) suggested that participants did not tend to recruit others with the same characteristics beyond what would be expected by chance.

CONCLUSION

Among this sample of WES in Seattle, Washington area, HCV seroprevalence was high and strongly associated with a history of IDU. The high burden of HCV among WES suggests this marginalized group would benefit from additional harm reduction services and targeted HCV treatment campaigns to reduce forward transmission. We saw little evidence of preferential recruitment among WES who were HCV seropositive or reported a history of IDU, suggesting the potential futility of peer-based referrals for HCV treatment.

Longitudinal changes in neurocognitive performance related to drug use intensity in a sample of persons with and without HIV who use illicit stimulants

BACKGROUND

Illicit stimulant use remains a public health concern that has been associated with multiple adverse outcomes, including cognitive deficits. The effects of stimulant use on cognition may be particularly deleterious in persons with HIV. Stimulant use intensity may be an important factor in the magnitude of observed deficits over time.

METHODS

We completed neurocognitive testing in a sample of people who use stimulants with (n = 84) and without HIV (n = 123) at baseline and up to 4 follow-up time points over approximately 1 year. Participants reported on substance use at each visit, including frequency of use and stimulant dependence. Mixed effects models examined the relationship between stimulant-related factors and neurocognitive function over time.

RESULTS

Participants were mostly male (57%), African American (86%), and 47.41 years old on average. All participants actively used stimulants at enrollment and use remained prevalent throughout the follow-up period, with an average of ≥24 days of use in the past 90 days at all time points. Retention was excellent, with 86% completing all 4 follow-up assessments. Mixed effects models showed that stimulant dependence was associated with lower neurocognitive performance independent of HIV status (p = 0.002), whereas frequency of use had a greater negative impact on performance in participants with HIV compared to those without HIV (p = 0.045).

CONCLUSIONS

Our key finding is that stimulant-related factors are associated with neurocognitive performance over time, but in complex ways. These findings have important implications for harm reduction approaches, particularly those that target cognitive function.

Gender, sexual orientation identity, and initiation of amphetamine injecting among people who inject drugs: Examination of an expanding drug era in Montreal, Canada, 2011-19

BACKGROUND

Amphetamine injection is expanding in North America and has been associated with male homosexuality among people who inject drugs (PWID). Applying subcultural evolution theory, we examined overall and gender-stratified trends in amphetamine injection and assessed sexual orientation as a gender-specific predictor of initiation among PWID in Montreal, Canada.

METHODS

Data were from HEPCO, an open prospective cohort of PWID. Gender and sexual orientation were self-identified at enrolment. Interviewer-administered questionnaires at three-monthly (HCV RNA-negative participants) or yearly (RNA-positive) intervals captured past three-month amphetamine injection and covariates. Annual prevalence and linear trends in amphetamine injection were estimated using GEE. Incidence was computed among naïve individuals and hazard ratios for initiation estimated using gender-stratified, time-varying Cox regression models.

RESULTS

803 participants contributed 8096 observations between March 2011 and December 2019. Annual prevalence of amphetamine injecting increased from 3.25% [95%CI: 2.06-4.43%] to 12.7% [9.50-16.0] (trend p<0.001). Bivariate Cox regression models suggested similar and divergent predictors of initiation by gender. Incidence was 3.27 per 100 person-years [95%CI: 2.51-4.18] among heterosexual men, 7.18 [3.50-13.2] among gay/bisexual men, 1.93 [0.78-4.02] among heterosexual women and 5.30 [1.69-12.8] among gay/bisexual women. Among men, gay/bisexual identity doubled risk of initiation after adjusting for age, ethnicity, calendar year (aHR 2.16 [1.07-4.36]) and additional covariates (2.56 [1.24-5.30]). Among women, evidence for an association with gay/bisexual identity was inconclusive (aHR 2.63 [0.62-11.2]) and sample size precluded further adjustment CONCLUSIONS: Prevalence of amphetamine injection among PWID increased four-fold from 2011 to 2019, with elevated risk of initiation in gay and bisexual men.

Real-world hepatitis C treatment outcomes and reinfections among people who inject drugs at a needle and syringe program in Stockholm, Sweden

BACKGROUND

People who inject drugs (PWID) represent a population with an increased prevalence of hepatitis C (HCV) infections. HCV treatment among PWID is essential to reach the WHO goal of eliminating HCV as a major public health threat by 2030. Despite better understanding of PWID subgroups and changes in risk behaviors over time, more knowledge about HCV treatment outcomes in different HCV prevalence populations and settings is warranted to enhance the continuum of care.

METHODS

All Stockholm Needle and Syringe Program (NSP) participants who initiated HCV treatment between October 2017 and June 2020 were HCV RNA tested at end of treatment and twelve weeks thereafter to confirm cure with a sustained virological response (SVR). All cured participants were prospectively followed from SVR to the last negative HCV RNA test or a subsequent reinfection, until October 31, 2021.

RESULTS

Overall, 409 NSP participants initiated HCV treatment, 162 at the NSP and 247 in another treatment setting. There were a total of 6.4% treatment dropouts (n = 26), 11.7% among participants treated at the NSP and 2.8% among those treated elsewhere (p < 0.001). Stimulant use (p < 0.05) and not being in an opioid agonist treatment program (p < 0.05) was associated with dropout. More participants treated outside the NSP were lost to follow-up between end of treatment and SVR (p < 0.05). During follow-up post-SVR, 43 reinfections occurred, corresponding to a reinfection rate of 9.3/100 PY (95% CI 7.0, 12.3). Factors associated with reinfection were younger age (p < 0.001), treatment while in prison (p < 0.01) and homelessness (p < 0.05).

DISCUSSION

In this high HCV prevalence NSP setting, with a majority of stimulant users, treatment success was high and the level of reinfections manageable. To reach HCV elimination, there is a need to target specific PWID subgroups for HCV treatment, in both harm reduction and adjacent healthcare settings frequented by PWID.

Increases in methamphetamine injection among treatment admissions in the U.S

BACKGROUND

Prior research indicates rising methamphetamine use and harms in the U.S., potentially related to increases in methamphetamine injection. To date, research on trends and correlates of methamphetamine injection is limited.

METHODS

Analysis of trends and correlates of methamphetamine injection among treatment admissions among persons aged ≥ 12 whose primary substance of use at admission is methamphetamine. Data are from the Treatment Episode Data Set. Analyses includes descriptive statistics, trend analyses, and multilevel multivariable logistic regression.

RESULTS

Primary methamphetamine treatment admissions increased from 138,379 in 2010 to 201,021 in 2019. Among primary methamphetamine admissions, injection as the usual route of use increased from 24,821 (18.0 % of admissions) in 2010 to 55,951 (28.2 % of admissions) in 2019. Characteristics associated with increased adjusted odds of reporting methamphetamine injection included: males (aOR = 1.13, 95 % CI = 1.10-1.15); admission age 25-34 years (aOR = 1.23, 95 % CI = 1.19-1.28) and 35-44 years (aOR = 1.12, 95 % CI = 1.08-1.17) compared to age 18-24; dependent living (aOR = 1.33, 95 % CI = 1.29-1.37) and homelessness (aOR = 1.58, 95 % CI = 1.54-1.63) compared to independent living; part-time employment (aOR = 1.08, 95 % CI = 1.02-1.14), unemployment (aOR = 1.39, 95 % CI = 1.34-1.44) and not in labor force (aOR = 1.43, 95 % CI = 1.37-1.49) compared to full-time employment; one to ≥ four prior treatment admissions (aORs ranging from 1.19 to 1.94) compared to no prior admissions; also reporting use of cocaine (aOR = 1.10, 95 % CI = 1.05-1.16), heroin (aOR = 3.52, 95 % CI = 3.40-3.66), prescription opioids (aOR = 1.61, 95 % CI = 1.54-1.67), or benzodiazepines (aOR = 1.42, 95 % CI = 1.32-1.52) at treatment admission.

CONCLUSIONS

Findings lend further evidence to a resurgence of methamphetamine use that is intertwined with the ongoing opioid crisis in the U.S. Efforts to expand evidence-based prevention, treatment, and response efforts, particularly to populations at highest risk, are urgently needed.

Qualitative inquiry into perceptions of HIV pre-exposure prophylaxis among people who inject drugs living with hepatitis C in Seattle, WA, USA

BACKGROUND

The incidence of HIV among persons who inject drugs (PWID) in the USA has been increasing since 2014, signaling the need to identify effective ways to engage PWID in HIV prevention services, namely pre-exposure prophylaxis (PrEP). Yet, the uptake of PrEP in this population is minimal compared to other populations at risk of HIV acquisition. In this work, we sought to explore knowledge, attitudes, and perspectives of PrEP acceptability among PWID.

METHODS

In the context of a pilot study to explore the acceptability of pharmacy-based hepatitis C virus (HCV) treatment, we conducted semi-structured interviews (n = 24) and focus groups (n = 4, 16 participants) with people who were living with HCV and reported active injection drug use (≤ 90 days since last use). Participants were asked open-ended questions about their familiarity with and motivation to use PrEP. As part of a sub-analysis focused on PrEP, qualitative data were analyzed using a Rapid Assessment Process, where three coders used structured templates to summarize qualitative data and iteratively reviewed coded templates to identify themes. Participants also completed short quantitative questionnaires regarding drug use history and attitudes toward health concerns.

RESULTS

Forty-seven percent of participants expressed having little or no concern regarding HIV acquisition. Targeted analyses focused on HIV prevention identified three themes, which help characterize behavioral determinants of nonadoption. First, knowledge of PrEP was limited among PWID and influenced by infrequent open community discussions around HIV risk. Second, PWID perceived sexual behaviors-but not injection drug use-as a motivator for HIV risk prevention. Finally, PWID identified many individual and environmental barriers that hinder PrEP uptake.

CONCLUSION

Among PWID, PrEP is rarely discussed and concerns about the feasibility of using daily PrEP are common. Taken with the prevalent perception that drug use is not a high risk for HIV acquisition, our findings point to opportunities for public health work to target PrEP education to PWID and to leverage other successful interventions for PWID as an opportunity to provide PrEP to this vulnerable population.

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.

Mathematical modeling of HIV-HCV co-infection model: Impact of parameters on reproduction number

Background: Hepatitis C Virus (HCV) and Human Immunodeficiency Virus (HIV) are both as classified blood-borne viruses since they are transmitted through contact with contaminated blood. Approximately 1.3 million of the 2.75 million global HIV/HCV carriers inject drugs (PWID). HIV co-infection has a harmful effect on the progression of HCV, resulting in greater rates of HCV persistence after acute infection, higher viral levels, and accelerated progression of liver fibrosis and end-stage liver disease. In this study, we developed and investigated a mathematical model for the dynamical behavior of HIV/AIDS and HCV co-infection, which includes therapy for both diseases, vertical transmission in HIV cases, unawareness and awareness of HIV infection, inefficient HIV treatment follow-up, and efficient condom use. Methods: Positivity and boundedness of the model under investigation were established using well-known theorems. The equilibria were demonstrated by bringing all differential equations to zero. The associative reproduction numbers for mono-infected and dual-infected models were calculated using the next-generation matrix approach. The local and global stabilities of the models were validated using the linearization and comparison theorem and the negative criterion techniques of bendixson and dulac, respectively. Results: The growing prevalence of HIV treatment dropout in each compartment of the HIV model led to a reduction in HIV on treatment compartments while other compartments exhibited an increase in populations . In dually infected patients, treating HCV first reduces co-infection reproduction number R ech , which reduces liver cancer risk. Conclusions: From the model's results, we infer various steps that policymakers could take to reduce the number of mono-infected and co-infected individuals.

Mathematical modeling of HIV-HCV co-infection model: Impact of parameters on reproduction number

Background: Hepatitis C Virus (HCV) and Human Immunodeficiency Virus (HIV) are both classified as blood-borne viruses since they are transmitted through contact with contaminated blood. Approximately 1.3 million of the 2.75 million global HIV/HCV carriers are people who inject drugs (PWID). HIV co-infection has a harmful effect on the progression of HCV, resulting in greater rates of HCV persistence after acute infection, higher viral levels, and accelerated progression of liver fibrosis and end-stage liver disease. In this study, we developed and investigated a mathematical model for the dynamical behavior of HIV/AIDS and HCV co-infection, which includes therapy for both diseases, vertical transmission in HIV cases, unawareness and awareness of HIV infection, inefficient HIV treatment follow-up, and efficient condom use. Methods: Positivity and boundedness of the model under investigation were established using well-known theorems. The equilibria were demonstrated by bringing all differential equations to zero. The associative reproduction numbers for mono-infected and dual-infected models were calculated using the next-generation matrix approach. The local and global stabilities of the models were validated using the linearization and comparison theorem and the negative criterion techniques of bendixson and dulac, respectively. Results: The growing prevalence of HIV treatment dropout in each compartment of the HIV model led to a reduction in HIV on treatment compartments while other compartments exhibited an increase in populations . In dually infected patients, treating HCV first reduces co-infection reproduction number R ech , which reduces liver cancer risk. Conclusions: From the model's results, we infer various steps (such as: campaigns to warn individuals about the consequences of having multiple sexual partners; distributing more condoms to individuals; continuing treatment for chronic HCV and AIDS) that policymakers could take to reduce the number of mono-infected and co-infected individuals.

Challenges of sexually transmitted infections and sexual health among people who inject drugs

PURPOSE OF REVIEW

This review provides a summary of recently published research on sexually transmitted infections (STI) and related behaviors among people who inject drugs (PWID), covering three major areas: sexual behavior and its role in STI transmission among PWID, multilevel factors associated with STI risk, and strategies addressing sexual health of PWID. This review is timely given the growing priority of combination prevention approaches and integrated care for PWID.

RECENT FINDINGS

Modern research improves the understanding that PWID have an increased risk of STI, which varies by gender, setting, type of substance used, and presence of mental disorders. Major socioeconomic and structural factors, specific and nonspecific to PWID, facilitate inequality and sexual risk behavior. Sexual transmission continues to contribute substantially to the spread of bloodborne infections among PWID, accounting for at least 10% of new HIV cases according to epidemiological modeling. Despite the substantial evidence that behavioral interventions can improve sexual health and reduce sex-related risks among PWID, there is a research-practice gap, reflected in the scarcity of implementation studies published recently.

SUMMARY

Integration of sexual health into prevention programs for PWID is essential to curb transmission of STI, including HIV, among PWID and their sexual partners.

Cardiac surgeons' perspectives and practices regarding people who use drugs: A scoping review

BACKGROUND AND AIM OF STUDY

The rising rates of drug use and associated cardiovascular complications, particularly infective endocarditis, have led to poorer health outcomes for people who use drugs (PWUD). The objectives of this scoping review were to identify (1) attitudes of cardiac surgeons toward PWUD and (2) challenges faced in the surgical treatment of drug use-related disease.

METHODS

A comprehensive literature search of three databases was performed with this assistance of a medical librarian. Articles were screened and analyzed for common themes by two independent authors. After literature review, a scoping review was conducted according to preferred reporting items for systematic reviews and meta-analyses and Joanna Briggs Institute guidelines, summarizing existing evidence.

RESULTS

Analysis of 35 qualified articles revealed eight themes regarding the perspectives and practices of cardiac surgeons toward PWUD: (1) need for multidisciplinary care teams (45.7%); (2) insufficient resources for treatment of underlying substanceuse disorders (40.0%); (3) stigma toward PWUD (37.1%); (4) willingness of surgeons to operate (31.4%); (5) incomplete guidelines for surgical management of drug-use related infective endocarditis (17.1%); (6) recognizing the importance of psychosocial factors (14.3%); (7) use of drug abstinence contracts (14.3%); and (8) use of stigmatizing language to describe PWUD and/or sterile injection (40.0%).

CONCLUSIONS

Provision of equitable care for PWUD requires effort from multiple disciplines including cardiothoracic surgeons, infectious disease specialists, addiction medicine specialists, and social workers. Additionally, further research is needed to gather sufficient data for evidence-based guidelines in the treatment of cardiac complications in PWUD.

Mapping drug epidemiology futures

Epidemiology is a core discipline generating evidence to inform and drive drug policy. In this essay, we speculate on what the future of drug epidemiology might become. We highlight for attention two areas shaping the future of drug epidemiology: nesting epidemiology within a 'syndemic' and 'relational' approach; and innovating in relation to causal inference in the face of complexity. We argue that shifts towards a more relational approach emphasise contingency, including in relation to how drugs might constitute benefit or harm. This leads us to speculate on a 'positive epidemiology'; one that is configured not merely in relation to harm but also in relation to the potential benefits of drugs in relation to well-being. In responding to the complex challenges of delineating contingent causalities, we emphasise the potential of carefully conducted observational study designs that go beyond statistical associations to test causal inference. We acknowledge that each of these developments we describe - a shift towards more relational approaches which emphasise contingent causation, and methodological innovations in relation to establishing causal inference - can be at odds with the other in how they imagine drug epidemiology futures.

Pilot study of extended-release lorcaserin for cocaine use disorder among men who have sex with men: A double-blind, placebo-controlled randomized trial

OBJECTIVE

To determine if men who have sex with men (MSM) with cocaine use disorder (CUD) and actively-using cocaine could be enrolled and retained in a pharmacologic intervention trial of lorcaserin-a novel 5-HT2cR agonist-and determine the degree to which participants would adhere to study procedures.

METHODS

This was a phase II randomized, double-blind, placebo-controlled pilot study with 2:1 random parallel group assignment to daily extended-release oral lorcaserin 20 mg versus placebo (clinicaltrials.gov identifier-NCT03192995). Twenty-two of a planned 45 cisgender MSM with CUD were enrolled and had weekly follow-up visits during a 12-week treatment period, with substance use counseling, urine specimen collection, and completion of audio-computer assisted self-interview (ACASI) behavioral risk assessments. Adherence was measured by medication event monitoring systems (MEMS) caps and self-report. This study was terminated early because of an FDA safety alert for lorcaserin's long-term use.

RESULTS

Eighty-six percent completed the trial, with 82% of weekly study follow-up visits completed. Adherence was 55.3% (lorcaserin 51.6% vs. placebo 66.2%) by MEMS cap and 56.9% (56.5% vs. placebo 57.9%) by self-report and did not differ significantly by treatment assignment. Intention-to-treat analyses (ITT) did not show differences in cocaine positivity by urine screen between the lorcaserin and placebo groups by 12 week follow-up (incidence risk ratio [IRR]: 0.96; 95%CI = 0.24-3.82, P = 0.95). However, self-reported cocaine use in timeline follow-back declined more significantly in the lorcaserin group compared to placebo (IRR: 0.66; 95%CI = 0.49-0.88; P = 0.004).

CONCLUSION

We found that it is feasible, acceptable, and tolerable to conduct a placebo-controlled pharmacologic trial for MSM with CUD who are actively using cocaine. Lorcaserin was not associated with significant reductions in cocaine use by urine testing, but was associated with significant reductions in self-reported cocaine use. Future research may be needed to continue to explore the potential utility of 5-HT2cR agonists.

Can hepatitis C elimination targets be sustained among people who inject drugs post-2030?

BACKGROUND

In high-income countries, people who inject drugs (PWID) are a priority population for eliminating hepatitis C virus (HCV) by 2030. Despite evidence informing micro-elimination strategies, little is known regarding efforts needed to maintain elimination targets in populations with ongoing acquisition risks. This model-based study investigates post-elimination transmission dynamics of HCV and HIV among PWID under different scenarios where harm reduction interventions and HCV testing and treatment are scaled-down.

METHODS

We calibrated a dynamic compartmental model of concurrent HCV and HIV transmission among PWID in Montréal (Canada) to epidemiological data (2003-2018). We then simulated achieving the World Health Organization elimination targets by 2030. Finally, we assessed the impact of four post-elimination scenarios (2030-2050): 1) scaling-down testing, treatment, opioid agonist therapy (OAT), and needle and syringe programs (NSP) to pre-2020 levels; 2) only scaling-down testing and treatment; 3) suspending testing and treatment, while scaling down OAT and NSP to pre-2020 levels; 4) suspending testing and treatment and maintaining OAT and NSP coverage required for elimination.

RESULTS

Scaling down interventions to pre-2020 levels (scenario 1) leads to a modest rebound in chronic HCV incidence from 2.4 to 3.6 per 100 person-years by 2050 (95% credible interval - CrI: 0.8-7.2). When only scaling down testing and treatment (scenario 2), chronic HCV incidence continues to decrease. In scenario 3 (suspending treatment and scaling down OAT and NSP), HCV incidence and mortality rapidly increase to 11.4 per 100 person-years (95%CrI: 7.4-15.5) and 3.2 per 1000 person-years (95%CrI: 2.4-4.0), respectively. HCV resurgence was mitigated in scenario 4 (maintaining OAT and NSP) as compared to scenario 3. All scenarios lead to decreases in the proportion of reinfections among incident cases and have little impact on HIV incidence and HIV-HCV coinfection prevalence.

CONCLUSION

Despite ongoing transmission risks, HCV incidence rebounds slowly after 2030 under pre-2020 testing and treatment levels. This is heightened by maintaining high-coverage harm reduction interventions. Overall, sustaining elimination would require considerably less effort than achieving it.

'Resurgent', 'twin' or 'silent' epidemic? A select data overview and observations on increasing psycho-stimulant use and harms in North America

In the early 2000s, increasing prevalence of psycho-stimulant (e.g., crack/cocaine, methamphetamine) use and related harms, including severe adverse health outcomes, was observed among - mostly marginalized - populations of persons using illicit drugs in North America, underscoring an urgent need for interventions options towards improved prevention and treatment. By about 2010, however, the 'opioid crisis', featuring unprecedented use and public health burden, had accelerated into full force in North America, largely muting attention to the psycho-stimulant issue until recently. Recent surveillance data on drug use and related mortality/morbidity from the present decade has documented a marked resurgence of psycho-stimulant use and harms especially in at-risk populations, commonly in direct combination with opioids, across North America, resulting in a 'twin epidemic' comprised of opioids and psycho-stimulants We briefly review select epidemiological data indicators for these developments from the United States and Canada; in the latter jurisdiction, related evidence has been less prevalent and systematic but corroborating the same trends. Evidently, the (widely ongoing) focus on the 'opioid epidemic' as a 'mono-type' drug problem has become an anachronism that requires urgent and appropriate correction. We then briefly consider existing, evidence-based options for - prevention and treatment - interventions targeting psycho-stimulant use and harms, which are substantially more limited and/or less efficacious than those available for problematic opioid use, while presenting major gaps and challenges. The observed resurgence of psycho-stimulants may, indirectly, relate to recent efforts towards curtailing (medical) opioid availability, thereby accelerating demand and supply for both illicit opioids and psycho-stimulants. The presently unfolding 'twin epidemic' of opioids and psycho-stimulants, combined with limited intervention resources, presents an acute challenge for public health and may crucially undermine actively extensive efforts to reduce opioid-related health harms in North America.