Differences in time to injection onset by drug in California: Implications for the emerging heroin epidemic

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.

The influence of transformations in supply on methamphetamine initiation among people injecting opioids in the United States

BACKGROUND

Co-use of methamphetamine (MA) and opioids (pharmaceutical pills, heroin and fentanyls) has increased in the United States and is represented in rising mortality. Although coinciding with the import of low cost, high potency and purity methamphetamine, the relationship between supply and demand in propelling this polydrug use is not well understood. We consider the influence of macro changes in supply on the uptake of opioid and methamphetamine co-use by injection at the level of individual drug and injection initiation in West Virginia, a state which leads the US in drug overdose mortality.

METHOD

We recruited n = 30 people for semi-structured interviews who self-reported injecting heroin/fentanyl and using methamphetamine by any route at a West Virginia syringe service program and through snowball sampling. Interviews were recorded and transcripts analyzed using a thematic approach. Ethnographic observation was also conducted and recorded in fieldnotes. Sequence of substance and mode of use initiation and use trajectories for opioids and stimulants were charted for each participant.

RESULTS

A clear pattern of individual drug initiation emerged that matched each successive supply wave of the US overdose epidemic: 25 participants had initiated opioid use with pills, followed by heroin, often mixed with/replaced by fentanyl, and subsequently added methamphetamine use. For participants, the supply and consumption of opioid analgesics had set in motion a series of steps leading to the addition of stimulant injection to existing opioid injecting repertoires. Unlike other studies that have found a birth cohort effect in patterns of initiation, participants showed the same sequence across age groups. Considerations of economy, availability, dependence, tolerance and the erosion of taboos that marked transitions from opioid pills to heroin injection influenced these subsequent trajectories in novel ways. The form, timing and extent of opioid and stimulant consumption was influenced by four stages of the changing drug supply, which in turn reflected back on demand.

CONCLUSION

Transformations in the social meaning and supply of methamphetamine enabled these transitions while other desired, non-injectable drugs were difficult to obtain. We discuss policy implications of injectable drugs' market dominance at this location and possible interventions.

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.

Early OxyContin Marketing Linked To Long-Term Spread Of Infectious Diseases Associated With Injection Drug Use

The initial marketing of the opioid analgesic OxyContin in 1996 increased fatal drug overdoses over the course of the opioid epidemic in the US. However, the long-term impacts of this marketing on complications of injection drug use, a key feature of the ongoing crisis, are undetermined. This study evaluated the effects of exposure to initial OxyContin marketing on the long-term trajectories of injection drug use-related outcomes in the US. We used a difference-in-differences analysis to compare outcomes in states with high versus low exposure to initial marketing before and after the 2010 reformulation of OxyContin, which facilitated the use of illicit drugs and the spread of infectious disease. Exposure to initial OxyContin marketing statistically significantly increased rates of fatal synthetic opioid-related overdoses; acute hepatitis A, B, and C viral infections; and infective endocarditis-related deaths. The greatest burden of adverse long-term outcomes has been in states that experienced the highest exposure to early OxyContin marketing. Our findings indicate that OxyContin marketing decisions from the mid-1990s increased viral and bacterial complications of injection drug use and illicit opioid-related overdose deaths twenty-five years later.

A Pilot Study of Polysubstance Use Sequences across the Lifespan among Assiniboine and Sioux People Who Use Injection Drugs

Compared with other racial/ethnic groups in the United States, American Indians/Alaska Natives have the highest rates of acute Hepatitis C Virus (HCV) infection, the highest HCV-related mortality, and one of the fastest climbing rates of drug overdose deaths involving stimulants. In this pilot study, a life history calendar was administered to Indigenous people who use injection drugs (IPWIDs) to understand sequences of polysubstance use across the lifespan. 40 IPWIDs completed a questionnaire and life history calendar. Social sequence analysis was used to examine patterns in sequential phenomena among substances reported over years of the lifespan. Most participants (55%) began injecting substances before the age of 21, 62.5% shared syringes with others, and 45% had ever been diagnosed with HCV. An appreciably large increase in the use of stimulants occurred between the year prior to and following injection initiation (33% to 82%). A three-cluster solution distinguished younger IPWIDs transitioning into polysubstance use involving stimulants and/or narcotic analgesics from adults using narcotic analgesics with stimulants over longer periods of time, and adults most focused on stimulant use over time. Findings from this pilot study contribute to an understanding of how methamphetamine injection plays a role in the HCV epidemic among IPWIDs.

Under the Skin: The Relationship Between Subcutaneous Injection and Skin Infections Among People Who Inject Drugs

OBJECTIVES

People who inject drugs (PWID) are at increased risk for numerous negative health outcomes. Subcutaneous injections (aka skin popping) can result in greater risk of skin and soft tissue infections (SSTIs), but less is known about PWID who choose this route of administration. This study compares subcutaneous injectors to intravenous injectors, characterizes those who inject subcutaneously, and examines whether subcutaneous injection is associated with SSTIs in the past year.

METHODS

A cohort of hospitalized PWID (n = 252) were interviewed regarding injection-related behaviors, history of SSTI, and knowledge of subcutaneous injection risk. We examined differences between those who do and do not inject subcutaneously and used a negative binomial regression model to estimate adjusted odds associating subcutaneous injection and SSTI.

RESULTS

Participants averaged 38 years, with 58.3% male, 59.5% White, 20.6% Black, and 15.9% Latinx. PWID who performed subcutaneous injection were not demographically different from other PWID; however, the mean rate of past year SSTIs was higher for persons injecting subcutaneously than for those who did not (1.98 vs 0.96, P < 0.001). Persons injecting subcutaneously did not differ from those who injected intravenously in terms of their knowledge of subcutaneous injection risk (P = 0.112) and knowledge score was not associated with SSTIs (P = 0.457).

CONCLUSIONS

PWID who perform subcutaneous injections are demographically similar to other PWID but had higher rates of past year SSTIs. Knowledge of subcutaneous injection risk was not associated with SSTI risk.

Cost-effectiveness of syringe service programs, medications for opioid use disorder, and combination programs in hepatitis C harm reduction among opioid injection drug users: a public payer perspective using a decision tree

BACKGROUND: The hepatitis C virus (HCV) prevalence rate among injection drug users (IDUs) in North America is 55.2%, with 1.41 million individuals estimated to be HCV-antibody positive. Studies have shown the effectiveness of syringe service programs (SSPs) alone, medications for opioid use disorder (MOUD) alone, or SSP+MOUD combination in reducing HCV transmission among opioid IDUs. OBJECTIVE: To evaluate the cost-effectiveness of SSP alone, MOUD alone, and SSP + MOUD combination in preventing HCV cases among opioid IDUs in the United States. METHODS: We used a decision tree analysis model based on published literature and publicly available data. Effectiveness was presented as the number of HCV cases avoided per 100 opioid IDUs. A micro-costing approach was undertaken and included both direct medical and nonmedical costs. Cost-effectiveness was assessed from a public payer perspective over a 1-year time horizon. It was expressed as an incremental cost-effectiveness ratio (ICER) and an incremental cost savings per HCV case avoided per 100 opioid IDUs compared with cost savings with "no intervention." Costs were standardized to 2019 U.S. dollars. RESULTS: The incremental cost savings per HCV case avoided per 100 opioid IDUs compared with no intervention were as follows: SSP + MOUD combination = $347,573; SSP alone = $363,821; MOUD alone = $317,428. The ICER for the combined strategy was $4,699 compared with the ICER for the SSP group. Sensitivity analysis showed that the results of the base-case cost-effectiveness analysis were sensitive to variations in the probabilities of injection-risk behavior for the SSP and SSP + MOUD combination groups, probability of no HCV with no intervention, and costs of MOUD and HCV antiviral medications. CONCLUSIONS: The SSP + MOUD combination and SSP alone strategies dominate MOUD alone and no intervention strategies. SSP had the largest incremental cost savings per HCV case avoided per 100 opioid IDUs compared with the no intervention strategy. Public payers adopting the SSP + MOUD combination harm-reduction strategy instead of SSP alone would have to pay an additional $4,699 to avoid an additional HCV case among opioid IDUs. Although these harm-reduction programs will provide benefits in a 1-year time frame, the largest benefit may become evident in the years ahead. DISCLOSURES: This research had no external funding. The authors declare no financial interests in this article. Ijioma is a Health Economics and Outcomes Research (HEOR) postdoctoral Fellow with Virginia Commonwealth University and Indivior. Indivior is a pharmaceutical manufacturer of opioid addiction treatment drugs but was not involved in the design, analysis, or write-up of the manuscript.

The Changing Epidemiology of Hepatitis C Virus Infection in the United States During the Years 2010 to 2018

Hepatitis C virus (HCV) infection remains an important cause of morbidity and mortality throughout the world, leading to serious health problems among those who are chronically infected. Since 1992, the Centers for Disease Control and Prevention has been collecting data on the incidence of HCV infection in the United States. In 2018, more than 50 000 individuals were estimated to have acute HCV infection.The most recently reported data on the prevalence of infection indicate that approximately 2.4 million people are living with hepatitis C in the United States. Transmission of HCV occurs predominantly through sharing contaminated equipment for injecting drugs.Two major events have had a significant impact on the incidence and prevalence of hepatitis C in the past few decades: the US opioid crisis and the discovery of curative treatments for HCV infection. To better understand the impact of these events, we examine reported trends in the incidence and prevalence of infection.

Cost-effectiveness of Direct Antiviral Agents for Hepatitis C Virus Infection and a Combined Intervention of Syringe Access and Medication-assisted Therapy for Opioid Use Disorders in an Injection Drug Use Population

BACKGROUND

There are too many plausible permutations and scale-up scenarios of combination hepatitis C virus (HCV) interventions for exhaustive testing in experimental trials. Therefore, we used a computer simulation to project the health and economic impacts of alternative combination intervention scenarios for people who inject drugs (PWID), focusing on direct antiviral agents (DAA) and medication-assisted treatment combined with syringe access programs (MAT+).

METHODS

We performed an allocative efficiency study, using a mathematical model to simulate the progression of HCV in PWID and its related consequences. We combined 2 previously validated simulations to estimate the cost-effectiveness of intervention strategies that included a range of coverage levels. Analyses were performed from a health-sector and societal perspective, with a 15-year time horizon and a discount rate of 3%.

RESULTS

From a health-sector perspective (excluding criminal justice system-related costs), 4 potential strategies fell on the cost-efficiency frontier. At 20% coverage, DAAs had an incremental cost-effectiveness ratio (ICER) of $27 251/quality-adjusted life-year (QALY). Combinations of DAA at 20% with MAT+ at 20%, 40%, and 80% coverage had ICERs of $165 985/QALY, $325 860/QALY, and $399 189/QALY, respectively. When analyzed from a societal perspective (including criminal justice system-related costs), DAA at 20% with MAT+ at 80% was the most effective intervention and was cost saving. While DAA at 20% with MAT+ at 80% was more expensive (eg, less cost saving) than MAT+ at 80% alone without DAA, it offered a favorable value compared to MAT+ at 80% alone ($23 932/QALY).

CONCLUSIONS

When considering health-sector costs alone, DAA alone was the most cost-effective intervention. However, with criminal justice system-related costs, DAA and MAT+ implemented together became the most cost-effective intervention.

A Review of Factors Associated with Age of First Injection

Injection drug use (IDU) is of increasing public health concern in the United States. Misuse of and addiction to opioids has contributed to declining life expectancies and rebounding risk of HIV and HCV acquisition among people who inject drugs. While some effective treatment strategies for individuals with substance use disorders have been established, effective interventions to prevent IDU require greater tailoring to subpopulations and social contexts. To better understand contextual variables associated with initiation of IDU, we conducted a narrative review of the existing literature that assessed correlates of age of first injection. We found sixteen studies that met our inclusion criteria. Across studies, later IDU initiation was associated with being African American and female, while early initiation was associated with earlier illicit substance use, childhood trauma, and incarceration. We also found that early initiation was associated with riskier substance-using behaviors, though the findings were mixed with respect to differences between early and late initiates in infectious disease prevalence. These correlates of age of first injection can potentially inform tailored injection prevention strategies. By identifying the features and behaviors of relevant subpopulations before they inject, interventions to prevent IDU could become more effective.

A Transitioning Epidemic: How The Opioid Crisis Is Driving The Rise In Hepatitis C

The hepatitis C virus is responsible for more deaths in the United States than any other infectious disease, and hepatitis C infections have been rising at an alarming rate since 2010. We evaluated the role of the opioid epidemic and, in particular, the 2010 introduction of an abuse-deterrent version of OxyContin. The OxyContin reformulation led some users of the drug to switch to heroin, which could have exposed them to the hepatitis C virus. We used difference-in-differences methods, using data for the period 2004-15, to assess whether states with higher rates of OxyContin misuse prior to reformulation-states where the reformulation had more impact-experienced faster growth in infections after the reformulation. States with above-median OxyContin misuse before the reformulation experienced a 222 percent increase in hepatitis C infection rates in the post-reformulation period, while states with below-median misuse experienced only a 75 percent increase. These results suggest that interventions to deter opioid misuse can have unintended long-term public health consequences.

Associations between perceived illicit fentanyl use and infectious disease risks among people who inject drugs

BACKGROUND

Over the last several years, fentanyl has been introduced into the illicit drug supply in the United States. While the impact of fentanyl on overdose fatalities is clear, the increase in fentanyl use may also be affecting drug use practices with implications for infectious disease transmission. We conducted a cross-sectional survey to explore associations of perceived illicit fentanyl use with opioid use frequency, injection frequency and syringe sharing among people who inject drugs in two California cities.

METHODS

People who inject drugs (PWID) were recruited from community settings in Los Angeles and San Francisco, CA from June 2017 to September 2018. Multivariable logistic regression was used to explore adjusted associations between perceived illicit fentanyl use and high frequency opioid use, high frequency injection and syringe sharing.

RESULTS

Among the 395 study participants, the median age of participants was 44 years; 74% of participants were cisgender male; 73% reported to be homeless; 61% lived in San Francisco and 39% in Los Angeles. The prevalence of perceived illicit fentanyl use in the past six months was 50.4% (95% confidence interval (CI): 45.4%-55.3%) among PWID. Findings from our adjusted logistic regression models suggested that people reporting perceived illicit fentanyl use had a greater odds of high frequency opioid use (adjusted odds ratio (aOR) = 2.36; 95% CI: 1.43-3.91; p = 0.001), high frequency injection (aOR = 1.84; 95% CI: 1.08-3.13; p = 0.03) and receptive syringe sharing (aOR = 2.16; 95% CI: 1.06-4.36; p = 0.03), as compared to people using heroin and other street drugs but not fentanyl.

CONCLUSION

People reporting perceived illicit fentanyl use were at increased risk for injection-related infectious disease risks. Actions must be taken to reduce these risks, including improved access to syringe service programs and opioid treatment and consideration of innovative approaches, such as supervised consumption services.

Gang Involvement and Drug Use Histories Among People Who Inject Drugs in California: A Retrospective Analysis

We examined whether gang membership history was associated with earlier age of first drug use, first drug injection, and shorter time to injection (TTI) drug use among people who inject drugs (PWID). PWID ( N = 438) were interviewed in California (2011-2013). Surveys addressed demographics, current/former drug use practices, gang membership, and parental drug use. Multivariate analyses were conducted to identify whether gang membership history was associated with age at first drug use, first injection drug use, and TTI. Gang membership was reported by 23% of sample. Gang membership history was associated with earlier ages of first drug use (–1.35 years; 95% confidence interval [CI]= [−0.50, −2.20]), age at first injection (–1.89 years; 95% CI = [0.00, −3.78]), but not TTI. Gang involvement facilitates drug use including earlier age of first injection drug use.

Factors Associated with Frequency of Recent Initiation of Others into Injection Drug Use Among People Who Inject Drugs in Los Angeles and San Francisco, CA, USA, 2016-17

Objective: Drug injection initiation is often assisted by a person who injects drugs (PWID). How often PWID provide this assistance has not been examined. We examine frequency of injection initiation assistance and factors associated with high (4+) and low frequency (1-3) initiation assistance as compared to no initiation assistance among PWID. Methods: Participants were 979 Californian PWID. PWID were interviewed about providing injection initiation assistance in the last 6 months among other items. Multinomial regression analysis was used to examine factors associated with levels of frequency of injection initiation assistance. Results: Among participants, 132 (14%) had initiated 784 people into injection (mean = 5.94 [standard deviation = 20.13]; median = 2, interquartile range = 1,4) in the last 6 months. PWID engaged in high frequency initiation (26% of sample) assisted 662 new initiates (84% of total). Using multinomial regression analysis with no initiating as the referent group, we found that high frequency initiating was statistically associated with higher injection frequency, having a paying sex partner, taking someone to a shooting gallery, and providing injection assistance. Lower frequency initiation was statistically associated with having a paying sex partner, illegal income source, and providing injection assistance. Conclusion: Differences between high and low frequency initiators were not found. Sex work and assisting with drug injection were linked to initiating others. Individual-level interventions that reduce this behavior among PWID and structural interventions such as safe consumption sites and opioid medication treatments that interrupt the social process of injection initiation should be considered as ways to reduce injection initiations.

Age of Initiation and Patterns of Use among People Who Inject Drugs Welcomed in Harm Reduction Facilities in France from 2006 to 2015

This exploratory analysis of time-series cross-sectional data provides insights on trends in age at first injection among people who inject drugs in France, and on associations with recent risky injecting behaviors. Data were collected from a national survey conducted in harm reduction facilities in five phases between 2006 and 2015. Standardized questionnaires collected information on demographics, substance use, and route of administration, as well as lifetime and past-month injection. Descriptive and multilevel models were applied to account for the hierarchical structure of the data. Prevalence of lifetime and past-month injection remained stable over time, while the prevalence of daily injection increased significantly. Mean age at first injection only appeared to increase for data collected after 2010. Gender differences in mean age at first injection decreased over time, suggesting the development of converging patterns of initiation independent of sex. After controlling for covariates, early initiation of injection was unrelated to daily injection or material sharing, and associated with the number of recently injected substances. Early initiation is likely a predictor of injected polysubstance use. Findings are relevant to the planning, implementation, and evaluation of prevention programs.

HIV infection among MSM who inject methamphetamine in 8 US cities

BACKGROUND AND AIMS

Men who have sex with men (MSM) and inject drugs are at risk for HIV infection. Although research exists on non-injection methamphetamine (meth) use and sexual risk among MSM, less is known about meth injection and its association with HIV infection among MSM who inject drugs.

METHODS

We analyzed data from men aged ≥18 years who reported injecting drugs and male-to-male sexual contact. Men were recruited using respondent-driven sampling, interviewed, and tested for HIV during the 2012 and 2015 cycles of National HIV Behavioral Surveillance among persons who inject drugs. We included data from 8 cities where ≥10 MSM reported meth as the primary drug injected. We assessed differences in demographic characteristics, past 12 months risk behaviors, and HIV infection between MSM who primarily injected meth and those who primarily injected another drug.

RESULTS

Among 961 MSM, 33.7% reported meth as the drug they injected most often. Compared to MSM who primarily injected other drugs, MSM who primarily injected meth were more likely to have had ≥5 condomless anal sex partners, have been diagnosed with syphilis, and were less likely to report sharing syringes. In multivariable analysis, injecting meth was associated with being HIV-positive (adjusted prevalence ratio 1.48; 95% confidence interval 1.08-2.03). Including number of condomless anal sex partners in mediation analysis rendered this association no longer significant.

CONCLUSIONS

HIV prevalence among MSM who primarily injected meth was almost 50% higher than among MSM who primarily injected other drugs, and this association was mediated by sexual risk.