Estimation of the cost-effectiveness of HIV prevention portfolios for people who inject drugs in the United States: A model-based analysis

Effectively engaging faith-based leaders on syringe services programs: U.S. pastors' knowledge, perceptions, and questions

OBJECTIVE

To identify faith-based leaders' (FBLs') knowledge, perceptions, and questions about syringe services programs (SSPs).

METHODS

We conducted a one-time, national online survey of 461 Christian FBLs August-September 2022.

RESULTS

56% of FBLs agreed they support having SSPs in their communities; only 7% strongly disagreed. We identified 15 main questions FBLs have about SSPs. We found statistically significant differences based on FBL Protestant affiliations. Mainline FBLs are more knowledgeable about SSPs, likely to believe a larger number of SSP services would benefit their community, supportive of SSPs, interested in data related to SSPs, and likely to look to local public health officials to shape their opinions on SSPs compared with non-mainline FBLs.

CONCLUSIONS

SSP advocates can address questions that FBLs have about SSPs before beginning outreach. By understanding common Protestant denominational affiliations, advocates can focus initial engagement efforts on FBLs in their communities who are more likely to support SSPs. Our findings suggest that local public health officials can influence FBLs' opinions about SSPs.

Past-Year HIV Testing, Current Antiretroviral Therapy Use, and Participation in Services for People Who Inject Drugs

Evaluating routine HIV testing and treatment and use of services for people who inject drugs (PWID) is critical to curb the ongoing HIV epidemic. We analyzed data from the 2018 National HIV Behavioral Surveillance of PWID aged 18 years or older, recruited using respondent-driven sampling and offered anonymous HIV testing after survey. We performed bivariate and multivariable analyses with log-linked Poisson regression of the generalized linear models to examine the associations between demographics and PWID service use, past-year HIV testing, and current antiretroviral therapy (ART) use. Among 10,311 HIV-negative PWID, 56% reported past-year HIV testing, and of the 553 HIV-positive PWID, 69% reported current ART use. Of the HIV-negative PWID, 64% (2874/4482) in drug treatment and 62% (3386/5440) who used syringe service programs (SSPs) reported past-year HIV testing. Among HIV-positive PWID, 75% (187/248) in drug treatment and 67% (200/298) SSP participants were on ART. In the adjusted multivariable model, past-year HIV testing was associated with drug use treatment (aPR 1.26, 95% CI 1.23-1.31) and SSP participation (aPR 1.19, 95% CI 1.13-1.26) among HIV-negative PWID. Current ART use was associated with drug use treatment (aPR 1.13, 95% CI 1.00-1.28) but the link was not significant probably due to small sample size. Findings support the expansion and improvement of PWID-targeted services, into comprehensive programs, including drug use treatment, SSP, and HIV testing and treatment.

The ASAM/AAAP Clinical Practice Guideline on the Management of Stimulant Use Disorder

The American Society of Addiction Medicine/American Academy of Addiction Psychiatry (ASAM/AAAP) Clinical Practice Guideline on the Management of Stimulant Use Disorder provides guidance on evidence-based strategies for the treatment of stimulant use disorders (StUDs), stimulant intoxication, and stimulant withdrawal, as well as secondary and tertiary prevention of harms associated with stimulant use. The Clinical Guideline Committee (CGC) comprised experts from ASAM and AAAP representing a range of clinical settings and patient populations. The guideline was developed following modified GRADE methodology. The process included a systematic literature review as well as several targeted supplemental searches. The CGC utilized Evidence to Decision tables to review available evidence and rate the strength of each recommendation. The clinical practice guideline was revised based on external stakeholder review. Key takeaways included: Contingency management represents the current standard of care for treatment of StUDs; Pharmacotherapies may be utilized off-label to treat StUDs; Acute stimulant intoxication can result in life-threatening complications that should be addressed in an appropriate level of care; Secondary and tertiary prevention strategies should be used to reduce harms related to risky stimulant use.

The Intersection of Substance Use Disorders and Infectious Diseases in the Emergency Department

Substance use disorders (SUDs) intersect clinically with many infectious diseases, leading to significant morbidity and mortality if either condition is inadequately treated. In this article, we will describe commonly seen SUDs in the emergency department (ED) as well as their associated infectious diseases, discuss social drivers of patient outcomes, and introduce novel ED-based interventions for co-occurring conditions. Clinicians should come away from this article with prescriptions for both antimicrobial medications and pharmacotherapy for SUDs, as well as an appreciation for social barriers, to care for these patients.

Harm Reduction for Opioid Use Disorder: Strategies and Outcome Metrics

Tweet: The authors discuss harm reduction strategies and associated outcome metrics in relation to the ongoing opioid crisis.

Rationale, evidence, and steps for implementation of medication for opioid use disorder treatment programs in HIV primary care settings

As the opioid crisis continues to escalate, the management of patients with opioid use disorder has crossed over to the care of patients with chronic infectious diseases, specifically HIV, HBV, and HCV, typically managed in the primary care setting. Consensus guidelines recommend testing for HIV and hepatitis in persons who inject drugs at least annually, but high-risk sexual activity may put other patients at risk as well. Significant barriers to robust care of these patient populations include low rates of HIV and hepatitis testing, limited access to methadone treatment programs, lack of widespread knowledge of how to prescribe office-based opioid treatment, and ongoing stigma surrounding prescribing of HIV treatment and prophylaxis medications. Clinical pharmacists across ambulatory, infectious diseases, and opioid stewardship specialties have the opportunity to play a key role in the implementation and support of harm reduction and medication for opioid use disorder services in the outpatient setting. The goal of this article is to discuss the rationale and evidence for these services and provide a framework for implementation.

A Bayesian Spatio-temporal Model to Optimize Allocation of Buprenorphine in North Carolina

The opioid epidemic is an ongoing public health crisis. In North Carolina, overdose deaths due to illicit opioid overdose have sharply increased over the last 5-7 years. Buprenorphine is a U.S. Food and Drug Administration approved medication for treatment of opioid use disorder and is obtained by prescription. Prior to January 2023, providers had to obtain a waiver and were limited in the number of patients that they could prescribe buprenorphine. Thus, identifying counties where increasing buprenorphine would yield the greatest overall reduction in overdose death can help policymakers target certain geographical regions to inform an effective public health response. We propose a Bayesian spatiotemporal model that relates yearly, county-level changes in illicit opioid overdose death rates to changes in buprenorphine prescriptions. We use our model to forecast the statewide count and rate of illicit opioid overdose deaths in future years, and we use nonlinear constrained optimization to identify the optimal buprenorphine increase in each county under a set of constraints on available resources. Our model estimates a negative relationship between death rate and increasing buprenorphine after accounting for other covariates, and our identified optimal single-year allocation strategy is estimated to reduce opioid overdose deaths by over 5.

Infectious Disease Modelling of HIV Prevention Interventions: A Systematic Review and Narrative Synthesis of Compartmental Models

BACKGROUND

The HIV epidemic remains a major public health problem. Critical to transmission control are HIV prevention strategies with new interventions continuing to be developed. Mathematical models are important for understanding the potential impact of these interventions and supporting policy decisions. This systematic review aims to answer the following question: when a new HIV prevention intervention is being considered or designed, what information regarding it is necessary to include in a compartmental model to provide useful insights to policy makers? The primary objective of this review is therefore to assess suitability of current compartmental HIV prevention models for informing policy development.

METHODS

Articles published in EMBASE, Medline, Econlit, and Global Health were screened. Included studies were identified using permutations of (i) HIV, (ii) pre-exposure prophylaxis (PrEP), circumcision (both voluntary male circumcision [VMMC] and early-infant male circumcision [EIMC]), and vaccination, and (iii) modelling. Data extraction focused on study design, model structure, and intervention incorporation into models. Article quality was assessed using the TRACE (TRAnsparent and Comprehensive Ecological modelling documentation) criteria for mathematical models.

RESULTS

Of 837 articles screened, 48 articles were included in the review, with 32 unique mathematical models identified. The substantial majority of studies included PrEP (83%), whilst fewer modelled circumcision (54%), and only a few focussed on vaccination (10%). Data evaluation, implementation verification, and model output corroboration were identified as areas of poorer model quality. Parameters commonly included in the mathematical models were intervention uptake and effectiveness, with additional intervention-specific common parameters identified. We identified key modelling gaps; critically, models insufficiently incorporate multiple interventions acting simultaneously. Additionally, population subgroups were generally poorly represented-with future models requiring improved incorporation of ethnicity and sexual risk group stratification-and many models contained inappropriate data in parameterisation which will affect output accuracy.

CONCLUSIONS

This review identified gaps in compartmental models to date and suggests areas of improvement for models focusing on new prevention interventions. Resolution of such gaps within future models will ensure greater robustness and transparency, and enable more accurate assessment of the impact that new interventions may have, thereby providing more meaningful guidance to policy makers.

The integration of harm reduction services in the Veterans Health Administration (VHA): a qualitative analysis of barriers and facilitators

BACKGROUND

Substance use is common among U.S. military veterans and veterans are at high risk for negative consequences associated with substance use, such as injection-related infections and overdose. Although harm reduction services (HRS) are highly evidence-based, implementation in traditional healthcare settings has been limited. This formative, qualitative study sought to identify barriers and facilitators to the integration of HRS and identify appropriate implementation strategies to support the optimized integration of a comprehensive bundle of HRS in the Veterans Health Administration (VHA).

METHODS

Semi-structured interviews explored how harm reduction is currently understood by VHA providers and elicited input on perceived facilitators and barriers to implementation. Data were analyzed using a directed content analysis and the Practical, Robust Implementation and Sustainability Model (PRISM) implementation framework was used to organize findings. Results were then mapped to relevant implementation strategies using the Consolidated Framework for Implementation Research - Expert Recommendations for Implementing Change (CFIR - ERIC) tool.

RESULTS

15 interviews with VHA providers were conducted across 5 sites. Respondents reported that current HRS are fragmented and dependent on the knowledge, time, and comfort level of individual providers. Stigma around substance use at the patient, provider, and institutional levels was noted to be a key barrier to HRS adoption. Based on identified barriers and facilitators, strategies that may be effective for increasing adoption of HRS include engagement of champions, communication and educational strategies, and adaptation of existing infrastructure.

CONCLUSIONS

Many of the barriers identified in this formative study may be addressed using evidence-based implementation strategies. Additional research is needed to identify implementation strategies that are effective for addressing stigma, which is perceived to be a persistent challenge to the provision of integrated harm reduction services.

Costs and Cost-Effectiveness of Biomedical, Non-Surgical HIV Prevention Interventions: A Systematic Literature Review

BACKGROUND

Considerable evidence on the costs and cost-effectiveness of biomedical, non-surgical interventions to prevent human immunodeficiency virus (HIV) transmission has been generated over the last decade. This study aims to synthesize findings and identify remaining knowledge gaps to suggest future research priorities.

METHODS

A systematic literature review was carried out in August 2020 using the MEDLINE, Embase, Global Health and EconLit databases to retrieve economic evaluations and costing studies of oral pre-exposure prophylaxis (PrEP), injectable long-acting PrEP, vaginal microbicide rings and gels, HIV vaccines and broadly neutralizing antibodies. Studies reporting costs from the provider or societal perspective were included in the analysis. Those reporting on behavioural methods of prevention, condoms and surgical approaches (voluntary medical male circumcision) were excluded. The quality of reporting of the included studies was assessed using published checklists.

RESULTS

We identified 3007 citations, of which 87 studies were retained. Most were set in low- and middle-income countries (LMICs; n = 53) and focused on the costs and/or cost-effectiveness of oral PrEP regimens (n = 70). Model-based economic evaluations were the most frequent study design; only two trial-based cost-effectiveness analyses and nine costing studies were found. Less than half of the studies provided practical details on how the intervention would be delivered by the health system, and only three of these, all in LMICs, explicitly focused on service integration and its implication for delivery costs. 'Real-world' programme delivery mechanisms and costs of intervention delivery were rarely considered. PrEP technologies were generally found to be cost-effective only when targeting high-risk subpopulations. Single-dose HIV vaccines are expected to be cost-effective for all groups despite substantial uncertainty around pricing.

CONCLUSIONS

A lack of primary, detailed and updated cost data, including above-service level costs, from a variety of settings makes it difficult to evaluate the cost-effectiveness of specific delivery modes at scale, or to evaluate strategies for services integration. Closing this evidence gap around real-world implementation is vital, not least because the strategies targeting high-risk groups that are recommended by PrEP models may incur substantially higher costs and be of limited practical feasibility in some settings.

Medical Complications of Injection Drug Use - Part II

Medical Complications of Injection Drug Use - Part IIDuring the past 2 decades, the risk of death, as well as the prevalence of hospitalizations in the United States, has increased substantially among people who inject drugs, mainly because of the opioid epidemic. In Part Two of this two-part review, the authors review complications observed in people who inject drugs and strategies to reduce harm.

The Cost-Effectiveness of HIV/STI Prevention in High-Income Countries with Concentrated Epidemic Settings: A Scoping Review

The purpose of this scoping review is to establish the state of the art on economic evaluations in the field of HIV/STI prevention in high-income countries with concentrated epidemic settings and to assess what we know about the cost-effectiveness of different measures. We reviewed economic evaluations of HIV/STI prevention measures published in the Web of Science and Cost-Effectiveness Registry databases. We included a total of 157 studies focusing on structural, behavioural, and biomedical interventions, covering a variety of contexts, target populations and approaches. The majority of studies are based on mathematical modelling and demonstrate that the preventive measures under scrutiny are cost-effective. Interventions targeted at high-risk populations yield the most favourable results. The generalisability and transferability of the study results are limited due to the heterogeneity of the populations, settings and methods involved. Furthermore, the results depend heavily on modelling assumptions. Since evidence is unequally distributed, we discuss implications for future research.

Long-Acting Injectable Human Immunodeficiency Virus Pre-Exposure Prophylaxis Preferred Over Other Modalities Among People Who Inject Drugs: Findings from a Qualitative Study in California

People who inject drugs (PWID) have extraordinarily low uptake of human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) despite high levels of need. Long-acting PrEP modalities hold promise for HIV prevention among PWID, but product preferences remain poorly understood. From September to November 2021, we conducted qualitative interviews with 28 HIV-negative, adult (≥18 years) PWID in San Diego County, CA, to explore their perspectives on daily oral PrEP pills and long-acting PrEP modalities (i.e., injections, implants, intravaginal rings, and broadly neutralizing antibodies), which we explained using standard scripts. Thematic analysis identified variations in PrEP modality interest and acceptability. We identified three key factors across the 28 interviews that appeared to influence PrEP modality preferences: perceived convenience of use, invasiveness, and familiarity (based on past experience). Overall, most participants preferred injectable PrEP over other modalities because they viewed injectable medications as convenient, noninvasive, and familiar. While injectable PrEP was recently approved for use in the United States and was most the acceptable PrEP modality in this sample, our findings suggest that intervention and implementation research is urgently needed to improve our understanding of strategies that could support access, uptake, and sustained adherence to longer-acting PrEP for PWID.

Modeling the impact of interventions during an outbreak of HIV infection among people who inject drugs in 2012-2013 in Athens, Greece

BACKGROUND

A large HIV outbreak in People Who Inject Drugs (PWID) occurred in Athens, Greece in 2011-2013. In response, opioid substitution treatment (OST) and needle and syringe programs (NSP) were scaled-up and a seek-test-treat program was introduced in mid-2012. We aim to assess the impact of these interventions.

METHODS

A mathematical model of HIV transmission among PWID was calibrated to data available over time (2009-2013) on HIV prevalence, NSP/antiretroviral treatment (ART) coverage and high-risk injection. A combined interventions scenario, including decrease in high-risk injection through linkage to OST and modification of risk behaviours and access to NSP and ART, was compared to a counterfactual scenario (no improvement at the levels of these interventions), with HIV incidence being the main outcome.

RESULTS

HIV incidence increased from <0.1 new cases/100 person-years (in 2009) to 11.0 new cases/100 person-years (in 2012). Under both models, a subsequent decline was projected following early 2012, with incidence at the end of 2013 in the combined interventions scenario being lower by 77% compared to the counterfactual. The projected reduction in incidence under the intervention scenario was in agreement with empirical data. HIV prevalence would have escalated to 20.4% (95% CrI: 16.9%, 23.6%) in 2013 under the counterfactual scenario (vs. 16.8% (95% CrI: 11.2%, 23.0%) under the combined interventions scenario). In total, 31.4% of HIV cases (392) were averted over 2012-2013.

CONCLUSION

These results underline the importance of high-coverage harm reduction programs and of community-based interventions to rapidly reach PWID most in need.

A Systematic Review of Simulation Models to Track and Address the Opioid Crisis

The opioid overdose crisis is driven by an intersecting set of social, structural, and economic forces. Simulation models are a tool to help us understand and address thiscomplex, dynamic, and nonlinear social phenomenon. We conducted a systematic review of the literature on simulation models of opioid use and overdose up to September 2019. We extracted modeling types, target populations, interventions, and findings; created a database of model parameters used for model calibration; and evaluated study transparency and reproducibility. Of the 1,398 articles screened, we identified 88 eligible articles. The most frequent types of models were compartmental (36%), Markov (20%), system dynamics (16%), and agent-based models (16%). Intervention cost-effectiveness was evaluated in 40% of the studies, and 39% focused on services for people with opioid use disorder (OUD). In 61% of the eligible articles, authors discussed calibrating their models to empirical data, and in 31%, validation approaches used in the modeling process were discussed. From the 63 studies that provided model parameters, we extracted the data sources on opioid use, OUD, OUD treatment, cessation or relapse, emergency medical services, and death parameters. From this database, potential model inputs can be identified and models can be compared with prior work. Simulation models should be used to tackle key methodological challenges, including the potential for bias in the choice of parameter inputs, investment in model calibration and validation, and transparency in the assumptions and mechanics of simulation models to facilitate reproducibility.

Using Economic Evaluation to Inform Responses to the Opioid Epidemic in the United States: Challenges and Suggestions for Future Research

Background: Several aspects of the opioid epidemic and of public health care organization in the United States (US) make the conduct of economic evaluation and the design of policies to respond to this crisis particularly challenging. Objectives: This commentary offers suggestions for how economic evaluation may address and overcome four key features of the opioid epidemic: 1) its magnitude and geographical distribution, 2) its intersection with multiple epidemics, 3) its rapidly changing dynamics, 4) its multi-sectoral causes and consequences. Results: We first offer pragmatic suggestions to address the difficulties in delivering a coordinated response given the fragmented nature of health care in the US. In view of the broad suite of responses required to address opioid use disorder and its associated comorbidities, we highlight the need for economic evaluations which consider interventions throughout the continuum of care (i.e. primary, secondary and tertiary levels of prevention). We examine how the use of predictive modelling alongside economic evaluation might be adopted to address the rapidly evolving situation affecting distinct populations and geographic areas and encourage investments in epidemic preparedness. Finally, we propose methods to capture the interdependence of various sectors of government affected by the opioid crisis in economic evaluations to ensure optimal levels of investment towards a comprehensive response. Conclusions: The opioid epidemic in the US represents an unprecedented public health challenge, but sound epidemiological modelling and economic analysis can help to guide use of limited resources committed to addressing it in ways that can have greatest impact in limiting its adverse consequences.

Syringe Coverage Among People Who Inject Drugs in West Virginia, USA

Ensuring people who inject drugs (PWID) have ≥ 100% sterile syringe coverage (i.e., persons have access to a sterile syringe for all injections) is optimal for HIV prevention. Existing syringe coverage literature is informative, yet little work has examined syringe coverage among PWID in rural communities. Using data from a 2018 PWID population estimation study conducted in a rural county in West Virginia, we used logistic regression to identify correlates of adequate sterile syringe coverage (at least 100%). A minority (37%) of PWID reported having adequate syringe coverage. Factors inversely associated with adequate syringe coverage included having recently (past 6 months): engaged in transactional sex work, shared syringes, and injected fentanyl. Having exclusively acquired syringes from a syringe services program was associated with increased odds of adequate syringe coverage. Rural PWID may benefit from tailored interventions designed to increase sterile syringe access.

Predicting the Effectiveness of Endemic Infectious Disease Control Interventions: The Impact of Mass Action versus Network Model Structure

BACKGROUND

Analyses of the effectiveness of infectious disease control interventions often rely on dynamic transmission models to simulate intervention effects. We aim to understand how the choice of network or compartmental model can influence estimates of intervention effectiveness in the short and long term for an endemic disease with susceptible and infected states in which infection, once contracted, is lifelong.

METHODS

We consider 4 disease models with different permutations of socially connected network versus unstructured contact (mass-action mixing) model and heterogeneous versus homogeneous disease risk. The models have susceptible and infected populations calibrated to the same long-term equilibrium disease prevalence. We consider a simple intervention with varying levels of coverage and efficacy that reduces transmission probabilities. We measure the rate of prevalence decline over the first 365 d after the intervention, long-term equilibrium prevalence, and long-term effective reproduction ratio at equilibrium.

RESULTS

Prevalence declined up to 10% faster in homogeneous risk models than heterogeneous risk models. When the disease was not eradicated, the long-term equilibrium disease prevalence was higher in mass-action mixing models than in network models by 40% or more. This difference in long-term equilibrium prevalence between network versus mass-action mixing models was greater than that of heterogeneous versus homogeneous risk models (less than 30%); network models tended to have higher effective reproduction ratios than mass-action mixing models for given combinations of intervention coverage and efficacy.

CONCLUSIONS

For interventions with high efficacy and coverage, mass-action mixing models could provide a sufficient estimate of effectiveness, whereas for interventions with low efficacy and coverage, or interventions in which outcomes are measured over short time horizons, predictions from network and mass-action models diverge, highlighting the importance of sensitivity analyses on model structure.

HIGHLIGHTS

• We calibrate 4 models-socially connected network versus unstructured contact (mass-action mixing) model and heterogeneous versus homogeneous disease risk-to 10% preintervention disease prevalence.• We measure the short- and long-term intervention effectiveness of all models using the rate of prevalence decline, long-term equilibrium disease prevalence, and effective reproduction ratio.• Generally, in the short term, prevalence declined faster in the homogeneous risk models than in the heterogeneous risk models.• Generally, in the long term, equilibrium disease prevalence was higher in the mass-action mixing models than in the network models, and the effective reproduction ratio was higher in network models than in the mass-action mixing models.

Perceptions of Syringe Service Programs and Supervised Use Sites Among a Sample of Registered Voters in a US State

CONTEXT

The decision to initiate a syringe service program or expand to a supervised use site is often influenced by local public support or opposition.

OBJECTIVE

The purpose of this study was to better understand public attitudes to local syringe service programs to inform the possibility of expanding services.

DESIGN, SETTING, AND PARTICIPANTS

We surveyed a sample of registered voters (n = 690) in the 8 counties in the state of Colorado with existing syringe service programs.

MAIN OUTCOME MEASURES

Respondents were asked about their awareness of and attitudes toward syringe service programs and supervised use sites.

RESULTS

More than three-fourths of respondents reported they were familiar with syringe service programs, but only a quarter knew they were legal, despite all survey respondents living near an operating program. Nearly one in 3 respondents thought a syringe service program or a supervised use site makes a community better, and a majority (57%) thought supervised use sites should be legal in their state. There were significant differences in attitudes toward the benefits and risks of syringe service programs by political party affiliation.

CONCLUSION

Understanding the level of community knowledge and support for syringe service programs, as well as the reasons for opposition, can be helpful in addressing community concerns when seeking to initiate or expand services.

Cost-effectiveness of Treatments for Opioid Use Disorder

IMPORTANCE

Opioid use disorder (OUD) is a significant cause of morbidity and mortality in the US, yet many individuals with OUD do not receive treatment.

OBJECTIVE

To assess the cost-effectiveness of OUD treatments and association of these treatments with outcomes in the US.

DESIGN AND SETTING

This model-based cost-effectiveness analysis included a US population with OUD.

INTERVENTIONS

Medication-assisted treatment (MAT) with buprenorphine, methadone, or injectable extended-release naltrexone; psychotherapy (beyond standard counseling); overdose education and naloxone distribution (OEND); and contingency management (CM).

MAIN OUTCOMES AND MEASURES

Fatal and nonfatal overdoses and deaths throughout 5 years, discounted lifetime quality-adjusted life-years (QALYs), and costs.

RESULTS

In the base case, in the absence of treatment, 42 717 overdoses (4132 fatal, 38 585 nonfatal) and 12 660 deaths were estimated to occur in a cohort of 100 000 patients over 5 years, and 11.58 discounted lifetime QALYs were estimated to be experienced per person. An estimated reduction in overdoses was associated with MAT with methadone (10.7%), MAT with buprenorphine or naltrexone (22.0%), and when combined with CM and psychotherapy (range, 21.0%-31.4%). Estimated deceased deaths were associated with MAT with methadone (6%), MAT with buprenorphine or naltrexone (13.9%), and when combined with CM, OEND, and psychotherapy (16.9%). MAT yielded discounted gains of 1.02 to 1.07 QALYs per person. Including only health care sector costs, methadone cost $16 000/QALY gained compared with no treatment, followed by methadone with OEND ($22 000/QALY gained), then by buprenorphine with OEND and CM ($42 000/QALY gained), and then by buprenorphine with OEND, CM, and psychotherapy ($250 000/QALY gained). MAT with naltrexone was dominated by other treatment alternatives. When criminal justice costs were included, all forms of MAT (with buprenorphine, methadone, and naltrexone) were associated with cost savings compared with no treatment, yielding savings of $25 000 to $105 000 in lifetime costs per person. The largest cost savings were associated with methadone plus CM. Results were qualitatively unchanged over a wide range of sensitivity analyses. An analysis using demographic and cost data for Veterans Health Administration patients yielded similar findings.

CONCLUSIONS AND RELEVANCE

In this cost-effectiveness analysis, expanded access to MAT, combined with OEND and CM, was associated with cost-saving reductions in morbidity and mortality from OUD. Lack of widespread MAT availability limits access to a cost-saving medical intervention that reduces morbidity and mortality from OUD. Opioid overdoses in the US likely reached a record high in 2020 because of COVID-19 increasing substance use, exacerbating stress and social isolation, and interfering with opioid treatment. It is essential to understand the cost-effectiveness of alternative forms of MAT to treat OUD.

Factors that influence enrollment in syringe services programs in rural areas: a qualitative study among program clients in Appalachian Kentucky

BACKGROUND

Enrolling sufficient number of people who inject drugs (PWID) into syringe services programs (SSP) is important to curtail outbreaks of drug-related harms. Still, little is known about barriers and facilitators to SSP enrollment in rural areas with no history of such programs. This study's purpose was to develop a grounded theory of the role of the risk environment and individual characteristics of PWID in shaping SSP enrollment in rural Kentucky.

METHODS

We conducted one-on-one semi-structured interviews with 41 clients of 5 SSPs that were established in rural counties in Appalachian Kentucky in 2017-2018. Interviews covered PWID needs, the process of becoming aware of SSPs, and barriers and facilitators to SSP enrollment. Applying constructivist grounded theory methods and guided by the Intersectional Risk Environment Framework (IREF), we applied open, axial and selective coding to develop the grounded theory.

RESULTS

Stigma, a feature of IREF's meso-level social domain, is the main factor hampering SSP enrollment. PWID hesitated to visit SSPs because of internalized stigma and because of anticipated stigma from police, friends, family and healthcare providers. Fear of stigma was often mitigated or amplified by a constellation of meso-level environmental factors related to healthcare (e.g., SSPs) and social (PWID networks) domains and by PWID's individual characteristics. SSPs mitigated stigma as a barrier to enrollment by providing low threshold services in a friendly atmosphere, and by offering their clients program IDs to protect them from paraphernalia charges. SSP clients spread positive information about the program within PWID networks and helped their hesitant peers to enroll by accompanying them to SSPs. Individual characteristics, including child custody, employment or high social status, made certain PWID more susceptible to drug-related stigma and hence more likely to delay SSP enrollment.

CONCLUSIONS

Features of the social and healthcare environments operating at the meso-level, as well as PWID's individual characteristics, appear to enhance or mitigate the effect of stigma as a barrier to SSP enrollment. SSPs opening in locations with high stigma against PWID need to ensure low threshold and friendly services, protect their clients from police and mobilize PWID networks to promote enrollment.

Health information technology interventions and engagement in HIV care and achievement of viral suppression in publicly funded settings in the US: A cost-effectiveness analysis

BACKGROUND

The US National HIV/AIDS Strategy (NHAS) emphasizes the use of technology to facilitate coordination of comprehensive care for people with HIV. We examined cost-effectiveness from the health system perspective of 6 health information technology (HIT) interventions implemented during 2008 to 2012 in a Ryan White HIV/AIDS Program (RWHAP) Special Projects of National Significance (SPNS) Program demonstration project.

METHODS/FINDINGS

HIT interventions were implemented at 6 sites: Bronx, New York; Durham, North Carolina; Long Beach, California; New Orleans, Louisiana; New York, New York (2 sites); and Paterson, New Jersey. These interventions included: (1) use of HIV surveillance data to identify out-of-care individuals; (2) extension of access to electronic health records (EHRs) to support service providers; (3) use of electronic laboratory ordering and prescribing; and (4) development of a patient portal. We employed standard microcosting techniques to estimate costs (in 2018 US dollars) associated with intervention implementation. Data from a sample of electronic patient records from each demonstration site were analyzed to compare prescription of antiretroviral therapy (ART), CD4 cell counts, and suppression of viral load, before and after implementation of interventions. Markov models were used to estimate additional healthcare costs and quality-adjusted life-years saved as a result of each intervention. Overall, demonstration site interventions cost $3,913,313 (range = $287,682 to $998,201) among 3,110 individuals (range = 258 to 1,181) over 3 years. Changes in the proportion of patients prescribed ART ranged from a decrease from 87.0% to 72.7% at Site 4 to an increase from 74.6% to 94.2% at Site 6; changes in the proportion of patients with 0 to 200 CD4 cells/mm3 ranged from a decrease from 20.2% to 11.0% in Site 6 to an increase from 16.7% to 30.2% in Site 2; and changes in the proportion of patients with undetectable viral load ranged from a decrease from 84.6% to 46.0% in Site 1 to an increase from 67.0% to 69.9% in Site 5. Four of the 6 interventions-including use of HIV surveillance data to identify out-of-care individuals, use of electronic laboratory ordering and prescribing, and development of a patient portal-were not only cost-effective but also cost saving ($6.87 to $14.91 saved per dollar invested). In contrast, the 2 interventions that extended access to EHRs to support service providers were not effective and, therefore, not cost-effective. Most interventions remained either cost-saving or not cost-effective under all sensitivity analysis scenarios. The intervention that used HIV surveillance data to identify out-of-care individuals was no longer cost-saving when the effect of HIV on an individual's health status was reduced and when the natural progression of HIV was increased. The results of this study are limited in that we did not have contemporaneous controls for each intervention; thus, we are only able to assess sites against themselves at baseline and not against standard of care during the same time period.

CONCLUSIONS

These results provide additional support for the use of HIT as a tool to enhance rapid and effective treatment of HIV to achieve sustained viral suppression. HIT has the potential to increase utilization of services, improve health outcomes, and reduce subsequent transmission of HIV.

The opioid crisis and HIV in the USA: deadly synergies

The opioid epidemic is one of the greatest public health problems that the USA faces. Opioid overdose death rates have increased steadily for more than a decade and doubled in 2013-17, as the highly potent synthetic opioid fentanyl entered the drug supply. Demographics of new HIV diagnoses among people who inject drugs are also changing, with more new HIV diagnoses occurring among White people, young people (aged 13-34 years), and people who reside outside large central metropolitan areas. Racial differences also exist in syringe sharing, which decreased among Black people and Hispanic people but remained unchanged among White people in 2005-15. Recent HIV outbreaks have occurred in rural areas of the USA, as well as among marginalised people in urban areas with robust HIV prevention and treatment services (eg, Seattle, WA). Multiple evidence-based interventions can effectively treat opioid use disorder and prevent HIV acquisition. However, considerable barriers exist precluding delivery of these solutions to many people who inject drugs. If the USA is serious about HIV prevention among this group, stigma must be eliminated, discriminatory policies must change, and comprehensive health care must be accessible to all. Finally, root causes of the opioid epidemic such as hopelessness need to be identified and addressed.

Human Immunodeficiency Virus Prevention for People Who Use Drugs: Overview of Reviews and the ICOS of PICOS

BACKGROUND

This article summarizes the results from systematic reviews of human immunodeficiency virus (HIV) prevention interventions for people who use drugs (PWUD). We performed an overview of reviews, meta-analysis, meta-epidemiology, and PROSPERO Registration CRD42017070117.

METHODS

We conducted a comprehensive systematic literature search using the Centers for Disease Control and Prevention HIV/AIDS Prevention Research Synthesis Project database to identify quantitative systematic reviews of HIV public heath interventions with PWUD published during 2002-2017. We recombined results of US studies across reviews to quantify effects on HIV infections, continuum of HIV care, sexual risk, and 5 drug-related outcomes (sharing injection equipment, injection frequency, opioid use, general drug use, and participation in drug treatment). We conducted summary meta-analyses separately for reviews of randomized controlled trials (RCTs) and quasi-experiments. We stratified effects by 5 intervention types: behavioral-psychosocial (BPS), syringe service programs (SSP), opioid agonist therapy (OAT), financial and scheduling incentives (FSI), and case management (CM).

RESULTS

We identified 16 eligible reviews including >140 US studies with >55 000 participants. Summary effects among US studies were significant and favorable for 4 of 5 outcomes measured under RCT (eg, reduced opioid use; odds ratio [OR] = 0.70, confidence interval [CI] = 0.56-0.89) and all 6 outcomes under quasi-experiments (eg, reduced HIV infection [OR = 0.42, CI = 0.27-0.63]; favorable continuum of HIV care [OR = 0.68, CI = 0.53-0.88]). Each intervention type showed effectiveness on 1-6 outcomes. Heterogeneity was moderate to none for RCT but moderate to high for quasi-experiments.

CONCLUSIONS

Behavioral-psychosocial, SSP, OAT, FSI, and CM interventions are effective in reducing risk of HIV and sequelae of injection and other drug use, and they have a continuing role in addressing the opioid crisis and Ending the HIV Epidemic.

From Hospital to the Community: Redesigning the Human Immunodeficiency Virus (HIV) Clinical Service Model to Respond to an Outbreak of HIV Among People Who Inject Drugs

An outbreak of human immunodeficiency virus (HIV) among people who inject drugs in Glasgow, Scotland started in 2014. We describe 156 cases over 5 years and evaluate the impact of clinical interventions using virological and phylogenetic analysis. We established (1) HIV services within homeless health facilities, including outreach nurses, and (2) antiretroviral therapy (ART) via community pharmacies. Implementation of the new model reduced time to ART initiation from 264 to 23 days and increased community viral load suppression rates to 86%. Phylogenetic analysis demonstrated that 2019 diagnoses were concentrated within a single network. Traditional HIV care models require adaptation for this highly complex population.

Ending the HIV Epidemic Among Persons Who Inject Drugs: A Cost-Effectiveness Analysis in Six US Cities

BACKGROUND

Persons who inject drugs (PWID) are at a disproportionately high risk of HIV infection. We aimed to determine the highest-valued combination implementation strategies to reduce the burden of HIV among PWID in 6 US cities.

METHODS

Using a dynamic HIV transmission model calibrated for Atlanta, Baltimore, Los Angeles, Miami, New York City, and Seattle, we assessed the value of implementing combinations of evidence-based interventions at optimistic (drawn from best available evidence) or ideal (90% coverage) scale-up. We estimated reduction in HIV incidence among PWID, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) for each city (10-year implementation; 20-year horizon; 2018 $ US).

RESULTS

Combinations that maximized health benefits contained between 6 (Atlanta and Seattle) and 12 (Miami) interventions with ICER values ranging from $94 069/QALY in Los Angeles to $146 256/QALY in Miami. These strategies reduced HIV incidence by 8.1% (credible interval [CI], 2.8%-13.2%) in Seattle and 54.4% (CI, 37.6%-73.9%) in Miami. Incidence reduction reached 16.1%-75.5% at ideal scale.

CONCLUSIONS

Evidence-based interventions targeted to PWID can deliver considerable value; however, ending the HIV epidemic among PWID will require innovative implementation strategies and supporting programs to reduce social and structural barriers to care.

Health outcomes and cost-effectiveness of diversion programs for low-level drug offenders: A model-based analysis

BACKGROUND

Cycles of incarceration, drug abuse, and poverty undermine ongoing public health efforts to reduce overdose deaths and the spread of infectious disease in vulnerable populations. Jail diversion programs aim to divert low-level drug offenders toward community care resources, avoiding criminal justice costs and disruptions in treatment for HIV, hepatitis C virus (HCV), and drug abuse. We sought to assess the health benefits and cost-effectiveness of a jail diversion program for low-level drug offenders.

METHODS AND FINDINGS

We developed a microsimulation model, calibrated to King County, Washington, that captured the spread of HIV and HCV infections and incarceration and treatment systems as well as preexisting interventions such as needle and syringe programs and opiate agonist therapy. We considered an adult population of people who inject drugs (PWID), people who use drugs but do not inject (PWUD), men who have sex with men, and lower-risk heterosexuals. We projected discounted lifetime costs and quality-adjusted life years (QALYs) over a 10-year time horizon with and without a jail diversion program and calculated resulting incremental cost-effectiveness ratios (ICERs) from the health system and societal perspectives. We also tracked HIV and HCV infections, overdose deaths, and jail population size. Over 10 years, the program was estimated to reduce HIV and HCV incidence by 3.4% (95% CI 2.7%-4.0%) and 3.3% (95% CI 3.1%-3.4%), respectively, overdose deaths among PWID by 10.0% (95% CI 9.8%-10.8%), and jail population size by 6.3% (95% CI 5.9%-6.7%). When considering healthcare costs only, the program cost $25,500/QALY gained (95% CI $12,600-$48,600). Including savings from reduced incarceration (societal perspective) improved the ICER to $6,200/QALY gained (95% CI, cost-saving $24,300). Sensitivity analysis indicated that cost-effectiveness depends on diversion program participants accessing community programs such as needle and syringe programs, treatment for substance use disorder, and HIV and HCV treatment, as well as diversion program cost. A limitation of the analysis is data availability, as fewer data are available for diversion programs than for more established interventions aimed at people with substance use disorder. Additionally, like any model of a complex system, our model relies on simplifying assumptions: For example, we simplified pathways in the healthcare and criminal justice systems, modeled an average efficacy for substance use disorder treatment, and did not include costs associated with homelessness, unemployment, and breakdown in family structure.

CONCLUSIONS

We found that diversion programs for low-level drug offenders are likely to be cost-effective, generating savings in the criminal justice system while only moderately increasing healthcare costs. Such programs can reduce incarceration and its associated costs, and also avert overdose deaths and improve quality of life for PWID, PWUD, and the broader population (through reduced HIV and HCV transmission).

Simulating the End of AIDS in New York: Using Participatory Dynamic Modeling to Improve Implementation of the Ending the Epidemic Initiative

OBJECTIVES

In 2014, the governor of New York announced the Ending the Epidemic (ETE) plan to reduce annual new HIV infections from 3000 to 750, achieve a first-ever decrease in HIV prevalence, and reduce AIDS progression by the end of 2020. The state health department undertook participatory simulation modeling to develop a baseline for comparing epidemic trends and feedback on ETE strategies.

METHODS

A dynamic compartmental model projected the individual and combined effects of 3 ETE initiatives: enhanced linkage to and retention in HIV treatment, increased preexposure prophylaxis (PrEP) among men who have sex with men, and expanded housing assistance. Data inputs for model calibration and low-, medium-, and high-implementation scenarios (stakeholders' rollout predictions, and lower and upper bounds) came from surveillance and program data through 2014, the literature, and expert judgment.

RESULTS

Without ETE (baseline scenario), new HIV infections would decline but remain >750, and HIV prevalence would continue to increase by 2020. Concurrently implementing the 3 programs would lower annual new HIV infections by 16.0%, 28.1%, and 45.7% compared with baseline in the low-, medium-, and high-implementation scenarios, respectively. In all concurrent implementation scenarios, although annual new HIV infections would remain >750, there would be fewer new HIV infections than deaths, yielding the first-ever decrease in HIV prevalence. PrEP and enhanced linkage and retention would confer the largest population-level changes.

CONCLUSIONS

New York State will achieve 1 ETE benchmark under the most realistic (medium) implementation scenario. Findings facilitated framing of ETE goals and underscored the need to prioritize men who have sex with men and maintain ETE's multipronged approach, including other programs not modeled here.

Roles for Pharmacists in the "Ending the HIV Epidemic: A Plan for America" Initiative

In 2019, President Trump announced a new initiative, Ending the HIV Epidemic: A Plan for America (EHE). EHE will use 3 key strategies-diagnose, treat, and prevent-to reduce new HIV infections at least 90% by 2030, as well as new laboratory methods and epidemiological techniques to respond quickly to potential outbreaks. Partnerships are an important component in the initiative's success. Pharmacists and pharmacies can play important roles in EHE, including dispensing antiretroviral therapy and providing HIV screening, adherence counseling, medication therapy management, preexposure prophylaxis, and nonprescription syringe sales. The objective of this report is to discuss potential roles that pharmacists and pharmacies can play under the key strategies of EHE.

America's opioid crisis: the need for an integrated public health approach

Continued increases in overdose deaths and recent declines in life expectancy call for need to adopt comprehensive public health approaches to the United States opioid crisis and to establish an infrastructure to avert future crises. Successfully addressing the challenges posed by the crisis requires a translational, integrated approach that combines the contribution of neuroscience, pharmacology, epidemiology, treatment services and prevention. It also is critical to integrate interventions across settings, including healthcare, justice, education and social service systems. This review highlights four interconnected themes: (1) social determinants of health and disease; (2) person-centered approaches for prevention and treatment; (3) bridging the gap between implementation science and practice; and (4) using data to build learning systems of care, relevant to public health approaches to address the opioid crisis. We discuss how across these four themes taking into account the influence of developmental factors on brain function and sensitivity to environmental stimuli including drugs, addressing the complex interactions between biological and social factors, and promoting an ongoing dialogue across disciplines and settings will help accelerate public health advances that are evidenced based and sustainable to address the current opioid crisis and avert future ones.

Development and Calibration of a Dynamic HIV Transmission Model for 6 US Cities

Background. Heterogeneity in HIV microepidemics across US cities necessitates locally oriented, combination implementation strategies to prioritize resources. We calibrated and validated a dynamic, compartmental HIV transmission model to establish a status quo treatment scenario, holding constant current levels of care for 6 US cities. Methods. Built off a comprehensive evidence synthesis, we adapted and extended a previously published model to replicate the transmission, progression, and clinical care for each microepidemic. We identified a common set of 17 calibration targets between 2012 and 2015 and used the Morris method to select the most influential parameters for calibration. We then applied the Nelder-Mead algorithm to iteratively calibrate the model to generate 2000 best-fitting parameter sets. Finally, model projections were internally validated with a series of robustness checks and externally validated against published estimates of HIV incidence, while the face validity of 25-year projections was assessed by a Scientific Advisory Committee (SAC). Results. We documented our process for model development, calibration, and validation to maximize its transparency and reproducibility. The projected outcomes demonstrated a good fit to calibration targets, with a mean goodness-of-fit ranging from 0.0174 (New York City [NYC]) to 0.0861 (Atlanta). Most of the incidence predictions were within the uncertainty range for 5 of the 6 cities (ranging from 21% [Miami] to 100% [NYC]), demonstrating good external validity. The face validity of the long-term projections was confirmed by our SAC, showing that the incidence would decrease or remain stable in Atlanta, Los Angeles, NYC, and Seattle while increasing in Baltimore and Miami. Discussion. This exercise provides a basis for assessing the incremental value of further investments in HIV combination implementation strategies tailored to urban HIV microepidemics.

HIV and Substance Use Disorder: Role of the HIV Physician

The ongoing syndemic of substance use disorder and human immunodeficiency virus infection threatens progress made in preventing new infections and improving outcomes among those infected. To address this challenge effectively, human immunodeficiency virus physicians must take an increased role in the screening, diagnosis, and treatment of substance use disorders. Such treatment decreases human immunodeficiency virus risk behaviors and improves human immunodeficiency virus and substance use disorder-related outcomes. An effective response to this syndemic requires increased access to adjuvant interventions and a radical movement away from the current stigmatization and criminalization of those suffering from substance use disorders.

Dual Unsafe Injection and Sexual Behaviors for HIV Infection Among People Who Inject Drugs in Iran

We used two national surveys (2010: N = 1597; 2013: N = 1057) of people who inject drugs (PWID) in past-month to assess the prevalence and population size of PWID with either safe or unsafe injection and sex behaviors, overall and by HIV status. In 2013, only 27.0% (vs. 32.3% in 2010) had safe injection and sex, 24.6% (vs. 23.3% in 2010) had unsafe injection and sex, 26.4% (vs. 26.5% in 2010) had only unsafe injection, and 22.0% (vs. 18.0% in 2010) had unsafe sex only. Among HIV-positive PWID in 2013, only 22.1% (~ 2200 persons) had safe injection and sex, 14.2% (~ 1400 persons) had unsafe injection and sex, 53.1% (~ 5200 persons) had unsafe injection, and 10.6% had unsafe sex (~ 1100 persons). Among HIV-negative PWID in 2013, only 27.5% (~ 22,200 persons) had safe injection and sex, 25.9% (~ 20,900 PWID) had unsafe injection and sex, 23.2% (~ 18,700 persons) had unsafe injection, and 23.3% (~ 18,800 persons) had unsafe sex. HIV-positive and -negative PWID in Iran continue to be at risk of HIV acquisition or transmission which calls for targeted preventions services.

Integrated Models of Care for Individuals with Opioid Use Disorder: How Do We Prevent HIV and HCV?

Purpose of Review

To describe models of integrated and co-located care for opioid use disorder (OUD), hepatitis C (HCV), and HIV.

Recent Findings

The design and scale-up of multidisciplinary care models that engage, retain, and treat individuals with HIV, HCV, and OUD are critical to preventing continued spread of HIV and HCV. We identified 17 models within primary care (N = 3), HIV specialty care (N = 5), opioid treatment programs (N = 6), transitional clinics (N = 2), and community-based harm reduction programs (N = 1), as well as two emerging models.

Summary

Key components of such models are the provision of (1) medication-assisted treatment for OUD, (2) HIV and HCV treatment, (3) HIV pre-exposure prophylaxis, and (4) behavioral health services. Research is needed to understand differences in effectiveness between co-located and fully integrated care, combat the deleterious racial and ethnic legacies of the “War on Drugs,” and inform the delivery of psychiatric care. Increased access to harm reduction services is crucial.

Electronic supplementary material

The online version of this article (10.1007/s11904-018-0396-x) contains supplementary material, which is available to authorized users.

Elimination of HIV transmission through novel and established prevention strategies among people who inject drugs

Despite the effectiveness of existing HIV prevention strategies for people who inject drugs (PWID), uncontrolled outbreaks of HIV among this group are common and occur around the world. In this Review, we summarise recent evidence for novel and established HIV prevention approaches to eliminate HIV transmission among PWID. Effective HIV prevention strategies include mobile needle and syringe programmes, pre-exposure prophylaxis, supervised injection facilities, and, to a lesser extent, some behavioural interventions. Studies have also shown the cost-effectiveness of long-standing HIV prevention strategies including needle and syringe programmes, opioid agonist therapy, and antiretroviral therapy for prevention. Although each individual intervention can reduce the risk of HIV acquisition among PWID, there is a consensus that a combination of approaches is required to achieve substantial and durable reductions in HIV transmission. Unfortunately, in many settings, the implementation of these interventions is often limited by public and political opposition that manifests as structural barriers to HIV prevention, such as the criminalisation of drug use. Given that there is ample evidence showing the effectiveness of several HIV prevention methods, social and political advocacy will be needed to overcome these barriers and integrate innovative HIV prevention approaches with addiction science to create effective drug policies.

Perspectives on HIV pre-exposure prophylaxis (PrEP) utilization and related intervention needs among people who inject drugs

Background

Antiretroviral pre-exposure prophylaxis (PrEP) is clinically efficacious and recommended for HIV prevention among people who inject drugs (PWID), but uptake remains low and intervention needs are understudied. To inform the development of PrEP interventions for PWID, we conducted a qualitative study in the Northeastern USA, a region where recent clusters of new HIV infections have been attributed to injection drug use.

Methods

We conducted qualitative interviews with 33 HIV-uninfected PWID (hereafter, “participants”) and 12 clinical and social service providers (professional “key informants”) in Boston, MA, and Providence, RI, in 2017. Trained interviewers used semi-structured interviews to explore PrEP acceptability and perceived barriers to use. Thematic analysis of coded data identified multilevel barriers to PrEP use among PWID and related intervention strategies.

Results

Among PWID participants (n = 33, 55% male), interest in PrEP was high, but both participants and professional key informants (n = 12) described barriers to PrEP utilization that occurred at one or more socioecological levels. Individual-level barriers included low PrEP knowledge and limited HIV risk perception, concerns about PrEP side effects, and competing health priorities and needs due to drug use and dependence. Interpersonal-level barriers included negative experiences with healthcare providers and HIV-related stigma within social networks. Clinical barriers included poor infrastructure and capacity for PrEP delivery to PWID, and structural barriers related to homelessness, criminal justice system involvement, and lack of money or identification to get prescriptions. Participants and key informants provided some suggestions for strategies to address these multilevel barriers and better facilitate PrEP delivery to PWID.

Conclusions

In addition to some of the facilitators of PrEP use identified by participants and key informants, we drew on our key findings and behavioral change theory to propose additional intervention targets. In particular, to help address the multilevel barriers to PrEP uptake and adherence, we discuss ways that interventions could target information, self-regulation and self-efficacy, social support, and environmental change. PrEP is clinically efficacious and has been recommended for PWID; thus, development and testing of strategies to improve PrEP delivery to this high-risk and socially marginalized population are needed.

Potential impact of implementing and scaling up harm reduction and antiretroviral therapy on HIV prevalence and mortality and overdose deaths among people who inject drugs in two Russian cities: a modelling study

BACKGROUND

Most new HIV infections among people who inject drugs (PWID) in eastern Europe and central Asia occur in Russia, where PWID have a high risk of overdose. In Russia, use of opioid agonist therapy (OAT) is prohibited, and coverage of needle and syringe programmes (NSPs) and antiretroviral therapy (ART) is poor. We aimed to assess the effects that scaling up harm reduction (ie, use of OAT and coverage of NSPs) and use of ART might have on HIV incidence and the frequency of fatal overdoses among PWID in two cities in the Ural Federal District and Siberian Federal District, where the prevalence of HIV is high or increasing in PWID.

METHODS

In this modelling study, we developed a dynamic deterministic model that simulated transmission of HIV through injection drug use and sex among PWID. We calibrated this model to HIV prevalence data among PWID in two Russian cities: Omsk (which has high but increasing prevalence of HIV among PWID) and Ekaterinburg (which has very high but stable prevalence of HIV). The source data were from research studies supported by the Global Fund to Fight AIDS, Tuberculosis, and Malaria and US Centers for Disease Control and Prevention and surveillance studies from WHO and regional AIDS centres. We modelled the effects of no intervention scale-up (no use of harm reduction measures and 30% of HIV-positive PWID receiving ART) versus combinations of scaling up of OAT, receipt of high coverage of NSPs, and use of ART on the incidence of HIV infections, mortality from HIV, and the frequency of fatal overdoses from 2018 to 2028.

FINDINGS

Without intervention, HIV prevalence among PWID in Omsk could increase from 30% in 2018 to 36% (2·5-97·5 percentile interval 22-52) in 2028 and remain high in Ekaterinburg, estimated at 60% (57-67) in 2028. Scaling up OAT to 50% coverage for a duration of 2 years could prevent 35% of HIV infections and 19% of deaths associated with HIV in Omsk and 20% (11-29) of HIV infections and 10% (4-14) of deaths associated with HIV in Ekaterinburg. Further, this scaling up could prevent 33% of overdose deaths over the next 10 years. Scaling up of NSPs and OAT to 50% coverage and tripling recruitment to ART (reaching about 65% of HIV-positive PWID) could prevent 58% (46-69) of HIV infections and 45% (36-54) of deaths associated with HIV in Omsk and 38% (26-50) of HIV infections and 32% (23-41) of deaths associated with HIV in Ekaterinburg by 2028.

INTERPRETATION

Legalisation of OAT and increased use of ART and NSPs for PWID are urgently needed to prevent HIV and fatal overdose among PWID in Russia.

FUNDING

National Institutes of Health and Elton John AIDS Foundation.

Cost and cost-effectiveness analysis of pre-exposure prophylaxis among men who have sex with men in two hospitals in Thailand

INTRODUCTION

In 2014, the Government of Thailand recommended pre-exposure prophylaxis (PrEP) as an additional HIV prevention programme within Thailand's National Guidelines on HIV/AIDS Treatment Prevention. However, to date implementation and uptake of PrEP programmes have been limited, and evidence on the costs and the epidemiological and economic impact is not available.

METHODS

We estimated the costs associated with PrEP provision among men having sex with men (MSM) participating in a facility-based, prospective observational cohort study: the Test, Treat and Prevent HIV Programme in Thailand. We created a suite of scenarios to estimate the cost-effectiveness of PrEP and sensitivity of the results to the model input parameters, including PrEP programme effectiveness, PrEP uptake among high-risk and low-risk MSM, baseline and future antiretroviral therapy (ART) coverage, condom use, unit cost of delivering PrEP, and the discount rate.

RESULTS

Drug costs accounted for 82.5% of the total cost of providing PrEP, followed by lab testing (8.2%) and personnel costs (7.8%). The estimated costs of providing the PrEP package in accordance with the national recommendation ranges from US$223 to US$311 per person per year. Based on our modelling results, we estimate that PrEP would be cost-effective when provided to either high-risk or all MSM. However, we found that the programme would be approximately 32% more cost-effective if offered to high-risk MSM than it would be if offered to all MSM, with an incremental cost-effectiveness ratio of US$4,836 per disability-adjusted life years (DALY) averted and US$7,089 per DALY averted respectively. Cost-effectiveness acceptability curves demonstrate that 80% of scenarios would be cost-effective when PrEP is provided solely to higher-risk MSM.

CONCLUSION

We provide the first estimates on cost and cost-effectiveness of PrEP in the Asia-Pacific region, and offer insights on how to deliver PrEP in combination with ART. While the high drug cost poses a budgeting challenge, incorporating PrEP delivery into an existing ART programme could be a cost-effective strategy to prevent HIV infections among MSM in Thailand.

Social and structural factors associated with greater time with a plasma HIV-1 RNA viral load above log10(1500) copies/ml among illicit drug users

OBJECTIVES

Although previous cross-sectional studies have identified correlates of detectable plasma HIV-1 RNA viral load (VL) among HIV-positive people who use drugs (PWUD), longitudinal factors associated with heightened HIV transmission potential have not been well described. Therefore, we longitudinally examined factors associated with amount of person-time spent above log10(1500) copies/ml plasma among HIV-positive PWUD in Vancouver, Canada.

DESIGN

Data were derived from a long-running prospective cohort of HIV-positive PWUD linked to comprehensive clinical records including systematic VL monitoring.

METHODS

We used generalized estimating equations modeling to longitudinally examine factors associated with person-time (in days) with a VL more than log10(1500) copies/ml plasma in the previous 180 days.

RESULTS

Between December 2005 and May 2014, 845 PWUD were eligible and included in the study. Participants spent an average of 26.8% of observation time with a VL more than log10(1500) copies/ml. In multivariable analyses, homelessness (Adjusted Rate Ratio [ARR] = 1.45) and lack of social support (ARR = 1.27) were positively associated with person-time with a VL more than log10(1500) copies/ml. Older age (ARR = 0.97) and enrolment in addiction treatment (ARR = 0.75) were negatively associated with the outcome in multivariable analyses (all P < 0.05).

CONCLUSION

Social and structural factors, including periods of homelessness or lacking in social support, were independently associated with greater amount of time with heightened HIV transmission potential. These findings suggest the need for targeted efforts to address modifiable contextual factors that contribute to increased risk of onward HIV transmission among PWUD.

Cost-effectiveness of alternative strategies for provision of HIV preexposure prophylaxis for people who inject drugs

BACKGROUND

Oral HIV preexposure prophylaxis (PrEP) has been recommended as a means of HIV prevention among people who inject drugs (PWIDs) but, at current prices, is unlikely to be cost-effective for all PWID.

OBJECTIVE

To determine the cost-effectiveness of alternative strategies for enrolling PWID in PrEP.

DESIGN

Dynamic network model that captures HIV transmission and progression among PWID in a representative US urban center.

OUTCOME MEASURES

HIV infections averted, discounted costs and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

INTERVENTION

We assume 25% PrEP coverage and investigate four strategies: first, random PWID are enrolled (Unselected Enrollment); second, individuals are randomly selected and enrolled together with their partners (Enroll Partners); third, individuals with the highest number of sexual and needle-sharing partnerships are enrolled (Most Partners); fourth, individuals with the greatest number of infected partners are enrolled (Most Positive Partners).

RESULTS

PrEP can achieve significant health benefits: compared with the status quo of no PrEP, the strategies gain 1114 QALYs (Unselected Enrollment), 2194 QALYs (Enroll Partners), 2481 QALYs (Most Partners), and 3046 QALYs (Most Positive Partners) over 20 years in a population of approximately 8500 people. The incremental cost-effectiveness ratio of each strategy compared with the status quo (cost per QALY gained) is $272 000 (Unselected Enrollment), $158 000 (Enroll Partners), $124 000 (Most Partners), and $101 000 (Most Positive Partners). All strategies except Unselected Enrollment are cost-effective according to WHO criteria.

CONCLUSION

Selection of high-risk PWID for PrEP can improve the cost-effectiveness of PrEP for PWID.

Structural Sensitivity in HIV Modeling: A Case Study of Vaccination

Structural assumptions in infectious disease models, such as the choice of network or compartmental model type or the inclusion of different types of heterogeneity across individuals, might affect model predictions as much as or more than the choice of input parameters. We explore the potential implications of structural assumptions on HIV model predictions and policy conclusions. We illustrate the value of inference robustness assessment through a case study of the effects of a hypothetical HIV vaccine in multiple population subgroups over eight related transmission models, which we sequentially modify to vary over two dimensions: parameter complexity (e.g., the inclusion of age and HCV comorbidity) and contact/simulation complexity (e.g., aggregated compartmental vs. individual/disaggregated compartmental vs. network models). We find that estimates of HIV incidence reductions from network models and individual compartmental models vary, but those differences are overwhelmed by the differences in HIV incidence between such models and the aggregated compartmental models (which aggregate groups of individuals into compartments). Complexities such as age structure appear to buffer the effects of aggregation and increase the threshold of net vaccine effectiveness at which aggregated models begin to overestimate reductions. The differences introduced by parameter complexity in estimated incidence reduction also translate into substantial differences in cost-effectiveness estimates. Parameter complexity does not appear to play a consistent role in differentiating the projections of network models.