Intervention Packages to Reduce the Impact of HIV and HCV Infections Among People Who Inject Drugs in Eastern Europe and Central Asia: A Modeling and Cost-effectiveness Study

Comparative costs and potential affordability of a multifaceted intervention to improve treatment outcomes among people with HIV who inject drugs in Russia: economic evaluation of the LINC-II randomized controlled trial

INTRODUCTION

The LINC-II randomized controlled trial in St. Petersburg, Russia for HIV-positive adults who inject drugs found that a multi-component intervention including initiation of antiretroviral therapy (ART) during admission to an addiction hospital, strengths-based case management and naltrexone significantly increased 12-month HIV viral suppression and ART retention. We conducted a comparative cost analysis to determine if the 12-month cost of the intervention is affordable within the current Russian health system.

METHODS

We used LINC-II trial records and questionnaire responses to calculate the resources utilized by each participant in the study, including inpatient days, medications, laboratory tests, outpatient consultations, case manager interactions and opioid medication treatment. Quantities of resources utilized were multiplied by unit costs for each resource estimated from the service fee or price lists used by the study facilities for each specific service delivered. We report the average cost/study primary (viral suppression at 12 months) or secondary (retention in care at 12 months) outcome/participant in 2021 USD and compare costs between study arms.

RESULTS

The trial enrolled 225 participants (111 intervention, 114 control) between September 2018 and December 2020. Viral suppression, non-suppression and missing suppression results were 28% and 14%, 49% and 37%, and 31% and 41% for the control and intervention arms, respectively. Retention results were 35% and 51% for the control and intervention arms, respectively. The average cost per study participant was $2714 in the control arm and $4342 in the intervention arm. The average cost per participant virally suppressed at 12 months was $3662 (control) and $6355 (intervention). The average cost per participant retained at 12 months was $4050 (control) and $5448 (intervention). For those retained, the cost difference between the arms was comprised of opioid treatment (35%), case management (31%), outpatient visits (18%) and additional days of ART (12%).

CONCLUSIONS

The LINC-II intervention increased the cost of care for HIV-positive people who inject drugs in Russia significantly, but some components of the intervention, particularly earlier initiation of ART and case management, may be justifiable due to their success in reaching a challenging subgroup of the population in need.

CLINICAL TRIAL NUMBER

NCT03290391.

Growth history of hepatitis C virus among HIV/HCV co-infected patients in Guizhou Province

Background: The evolutionary and epidemiological history and the regional differences of various hepatitis C virus (HCV) genotypes are complex. Our aim was to better understand the molecular epidemiology and evolutionary dynamics of HCV among HIV/HCV co-infected individuals in Guizhou Province. This information could contribute to improve HCV prevention and control strategies in Guizhou and surrounding provinces. Methods: The HCV RNA was extracted from the serum of HIV/HCV co-infected patients, and reverse transcription/nested PCR was performed to amplify nucleotide sequences of the C-E1 region. Then, the successfully amplified sequences were selected for phylogenetic analysis. The available C-E1 region reference sequences from the surrounding provinces of Guizhou (Guangxi, Yunnan, Hunan, and Sichuan) were retrieved in GenBank, and the evolutionary analysis by Bayesian Markov chain Monte Carlo (MCMC) algorithm was performed using BEAST software to reconstruct a phylogeographic tree in order to explore their migration patterns. Finally, the epidemiological history of HCV in the Guizhou region was retraced by reconstructing Bayesian skyline plots (BSPs) after excluding sequences from surrounding provinces. Results: Among 186 HIV/HCV co-infected patients, the C-E1 region sequence was successfully amplified in 177 cases. Phylogenetic analysis classified these sequences into six subtypes: 1a, 1b, 3a, 3b, 6a, and 6n. Among them, subtype 6a was the most dominant strain (n = 70), followed by 3b (n = 55), 1b (n = 31), 3a (n = 11), 1a (n = 8), and 6n (n = 2). By reconstructing the phylogeographic tree, we estimated that the 6a strain in Guizhou mainly originated from Yunnan and Guangxi, while the 3b strain emerged due to transmission from the IDU network in Yunnan. Subtypes 1b, 3a, 3b, and 6a, as the major subtypes of HCV in HIV/HCV co-infected individuals in Guizhou, emerged and later grew more rapidly than the national average. Notably, BSPs of the currently prevalent HCV predominant strain subtype 6a in Guizhou have shown a rapid population growth since 2004. Although the growth rate slowed down around 2010, this growth has continued to date. Conclusion: Overall, despite the improvement and implementation of a series of HCV prevention and control policies and measures, a delayed growth pattern may indicate a unique history of the spread of 6a in Guizhou. Its trend as the dominant strain in Guizhou in recent years may continue to increase slowly over subsequent years.

An intensive model of care for hepatitis C virus screening and treatment with direct-acting antivirals in people who inject drugs in Nairobi, Kenya: a model-based cost-effectiveness analysis

BACKGROUND AND AIMS

Hepatitis C virus (HCV) treatment is essential for eliminating HCV in people who inject drugs (PWID), but has limited coverage in resource-limited settings. We measured the cost-effectiveness of a pilot HCV screening and treatment intervention using directly observed therapy among PWID attending harm reduction services in Nairobi, Kenya.

DESIGN

We utilized an existing model of HIV and HCV transmission among current and former PWID in Nairobi to estimate the cost-effectiveness of screening and treatment for HCV, including prevention benefits versus no screening and treatment. The cure rate of treatment and costs for screening and treatment were estimated from intervention data, while other model parameters were derived from literature. Cost-effectiveness was evaluated over a life-time horizon from the health-care provider's perspective. One-way and probabilistic sensitivity analyses were performed.

SETTING

Nairobi, Kenya.

POPULATION

PWID.

MEASUREMENTS

Treatment costs, incremental cost-effectiveness ratio (cost per disability-adjusted life year averted).

FINDINGS

The cost per disability-adjusted life-year averted for the intervention was $975, with 92.1% of the probabilistic sensitivity analyses simulations falling below the per capita gross domestic product for Kenya ($1509; commonly used as a suitable threshold for determining whether an intervention is cost-effective). However, the intervention was not cost-effective at the opportunity cost-based cost-effectiveness threshold of $647 per disability-adjusted life-year averted. Sensitivity analyses showed that the intervention could provide more value for money by including modelled estimates for HCV disease care costs, assuming lower drug prices ($75 instead of $728 per course) and excluding directly-observed therapy costs.

CONCLUSIONS

The current strategy of screening and treatment for hepatitis C virus (HCV) among people who inject drugs in Nairobi is likely to be highly cost-effective with currently available cheaper drug prices, if directly-observed therapy is not used and HCV disease care costs are accounted for.

Costs and impact on HIV transmission of a switch from a criminalisation to a public health approach to injecting drug use in eastern Europe and central Asia: a modelling analysis

BACKGROUND

HIV incidence is increasing in eastern Europe and central Asia, primarily driven by injecting drug use. Coverage of antiretroviral therapy (ART) and opioid agonist therapy are suboptimal, with many people who inject drugs (PWID) being incarcerated. We aimed to assess whether use of monies saved as a result of decriminalisation of drug use or possession to scale up ART and opioid agonist therapy could control HIV transmission among PWID in eastern Europe and central Asia.

METHODS

A dynamic HIV transmission model among PWID incorporating incarceration, ART, and opioid agonist therapy was calibrated to Belarus, Kazakhstan, Kyrgyzstan, and St Petersburg (Russia). Country-specific costs for opioid agonist therapy, ART, and incarceration were collated or estimated. Compared with baseline, the model prospectively projected the life-years gained, incremental costs (2018 euros), and infections prevented over 2020-40 for three scenarios. The decriminalisation scenario removed incarceration resulting from drug use or possession for personal use, reducing incarceration among PWID by 24·8% in Belarus, Kazakhstan, and Kyrgyzstan and 46·4% in St Petersburg; the public health approach scenario used savings from decriminalisation to scale up ART and opioid agonist therapy; and the full scale-up scenario included the decriminalisation scenario plus investment of additional resources to scale up ART to the UNAIDS 90-90-90 target of 81% coverage and opioid agonist therapy to the WHO target of 40% coverage. The incremental cost-effectiveness ratios per life-year gained for each scenario were calculated and compared with country-specific gross domestic product per-capita willingness-to-pay thresholds. Costs and life-years gained were discounted 3% annually.

FINDINGS

Current levels of incarceration, opioid agonist therapy, and ART were estimated to cost from €198 million (95% credibility interval 173-224) in Kyrgyzstan to €4129 million (3897-4358) in Kazakhstan over 2020-40; 74·8-95·8% of these total costs were incarceration costs. Decriminalisation resulted in cost savings (€38-773 million due to reduced prison costs; 16·9-26·1% reduction in overall costs) but modest life-years gained (745-1694). The public health approach was cost saving, allowing each setting to reach 81% ART coverage and 29·7-41·8% coverage of opioid agonist therapy, resulting in 17 768-148 464 life-years gained and 58·9-83·7% of infections prevented. Results were similar for the full scale-up scenario.

INTERPRETATION

Cost savings from decriminalisation of drug use could greatly reduce HIV transmission through increased coverage of opioid agonist therapy and ART among PWID in eastern Europe and central Asia.

FUNDING

Alliance for Public Health, US National Institute of Allergy and Infectious Diseases and National Institute for Drug Abuse, and Economist Intelligence Unit.

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 offer a tool to help us understand and address this complex, 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. Further, we 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%). Over a third evaluated intervention cost-effectiveness (40%), and another third (39%) focused on treatment and harm reduction services for people with opioid use disorder (OUD). More than half (61%) discussed calibrating their models to empirical data, and 31% discussed validation approaches used in their modeling process. From the 63 studies that provided model parameters, we extracted the data sources on opioid use, OUD, OUD treatment, cessation/relapse, emergency medical services, and mortality parameters. This database offers a tool that future modelers can use to identify potential model inputs and evaluate comparability of their models to prior work. Future applications of simulation models to this field should actively 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.

Elucidating Drivers for Variations in the Explosive Human Immunodeficiency Virus Epidemic Among People Who Inject Drugs in Pakistan

Background

Pakistan’s explosive human immunodeficiency virus (HIV) epidemic among people who inject drugs (PWID) varies widely across cities. We evaluated possible drivers for these variations.

Methods

Multivariable regression analyses were undertaken using data from 5 national surveys among PWID (n = 18 467; 2005–2017) to determine risk factors associated with variations in city-level HIV prevalence. A dynamic HIV model was used to estimate the population-attributable fraction (PAF; proportion of HIV infections prevented over 10 years when that risk factor is removed) of these risk factors to HIV transmission and impact on HIV incidence of reducing their prevalence.

Results

Regression analyses suggested that city-level HIV prevalence is strongly associated with the prevalence of using professional injectors at last injection, heroin use in last month, and injecting ≥4 times per day. Through calibrating a model to these associations, we estimate that the 10-year PAFs of using professional injectors, heroin use, and frequent injecting are 45.3% (95% uncertainty interval [UI], 4.3%–79.7%), 45.9% (95% UI, 8.1%–78.4%), and 22.2% (95% UI, 2.0%–58.4%), respectively. Reducing to lowest city-level prevalences of using professional injectors (2.8%; median 89.9% reduction), heroin use (0.9%; median 91.2% reduction), and frequent injecting (0.1%; median 91.8% reduction) in 2020 reduces overall HIV incidence by 52.7% (95% UI, 6.1%–82.0%), 53.0% (95% UI, 11.3%–80.2%), and 28.1% (95% UI, 2.7%–66.6%), respectively, over 10 years.

Conclusions

Interventions should focus on these risk factors to control Pakistan’s explosive HIV epidemic among PWID, including a concomitant expansion of high-coverage needle/syringe provision, opioid substitution therapy, and antiretroviral therapy.

Evolving HIV epidemics: the urgent need to refocus on populations with risk

Purpose of review

To explore the comparative importance of HIV infections among key populations and their intimate partners as HIV epidemics evolve, and to review implications for guiding responses.

Recent findings

Even as concentrated epidemics evolve, new infections among current and former key population members and their intimate partners dominate new infections. Prevalent infections in the general population grow primarily because of key population turnover and infections among their intimate partners. In generalized epidemic settings, data and analysis on key populations are often inadequate to assess the impact of key population-focused responses, so they remain limited in coverage and under resourced. Models must incorporate downstream infections in comparing impacts of alternative responses.

Summary

Recognize that every epidemic is unique, moving beyond the overly simplistic concentrated/generalized epidemic paradigm that can misdirect resources. Guide HIV responses by gathering and using locally relevant data, understanding risk heterogeneity, and applying modeling at both national and sub-national levels to optimize resource allocations among different populations for greatest impact. Translate this improved understanding into clear, unequivocal advice for policymakers on where to focus for impact, breaking them free of the generalized/concentrated paradigm limiting their thinking and affecting their decisions.

Effects and cost of different strategies to eliminate hepatitis C virus transmission in Pakistan: a modelling analysis

BACKGROUND

The WHO elimination strategy for hepatitis C virus advocates scaling up screening and treatment to reduce global hepatitis C incidence by 80% by 2030, but little is known about how this reduction could be achieved and the costs of doing so. We aimed to evaluate the effects and cost of different strategies to scale up screening and treatment of hepatitis C in Pakistan and determine what is required to meet WHO elimination targets for incidence.

METHODS

We adapted a previous model of hepatitis C virus transmission, treatment, and disease progression for Pakistan, calibrating using available data to incorporate a detailed cascade of care for hepatitis C with cost data on diagnostics and hepatitis C treatment. We modelled the effect on various outcomes and costs of alternative scenarios for scaling up screening and hepatitis C treatment in 2018-30. We calibrated the model to country-level demographic data for 1960-2015 (including population growth) and to hepatitis C seroprevalence data from a national survey in 2007-08, surveys among people who inject drugs (PWID), and hepatitis C seroprevalence trends among blood donors. The cascade of care in our model begins with diagnosis of hepatitis C infection through antibody screening and RNA confirmation. Diagnosed individuals are then referred to care and started on treatment, which can result in a sustained virological response (effective cure). We report the median and 95% uncertainty interval (UI) from 1151 modelled runs.

FINDINGS

One-time screening of 90% of the 2018 population by 2030, with 80% referral to treatment, was projected to lead to 13·8 million (95% UI 13·4-14·1) individuals being screened and 350 000 (315 000-385 000) treatments started annually, decreasing hepatitis C incidence by 26·5% (22·5-30·7) over 2018-30. Prioritised screening of high prevalence groups (PWID and adults aged ≥30 years) and rescreening (annually for PWID, otherwise every 10 years) are likely to increase the number screened and treated by 46·8% and decrease incidence by 50·8% (95% UI 46·1-55·0). Decreasing hepatitis C incidence by 80% is estimated to require a doubling of the primary screening rate, increasing referral to 90%, rescreening the general population every 5 years, and re-engaging those lost to follow-up every 5 years. This approach could cost US$8·1 billion, reducing to $3·9 billion with lowest costs for diagnostic tests and drugs, including health-care savings, and implementing a simplified treatment algorithm.

INTERPRETATION

Pakistan will need to invest about 9·0% of its yearly health expenditure to enable sufficient scale up in screening and treatment to achieve the WHO hepatitis C elimination target of an 80% reduction in incidence by 2030.

FUNDING

UNITAID.

Opioid agonist treatment scale-up and the initiation of injection drug use: A dynamic modeling analysis

BACKGROUND

Injection drug use (IDU) is associated with multiple health harms. The vast majority of IDU initiation events (in which injection-naïve persons first adopt IDU) are assisted by a person who injects drugs (PWID), and as such, IDU could be considered as a dynamic behavioral transmission process. Data suggest that opioid agonist treatment (OAT) enrollment is associated with a reduced likelihood of assisting with IDU initiation. We assessed the association between recent OAT enrollment and assisting IDU initiation across several North American settings and used dynamic modeling to project the potential population-level impact of OAT scale-up within the PWID population on IDU initiation.

METHODS AND FINDINGS

We employed data from a prospective multicohort study of PWID in 3 settings (Vancouver, Canada [n = 1,737]; San Diego, United States [n = 346]; and Tijuana, Mexico [n = 532]) from 2014 to 2017. Site-specific modified Poisson regression models were constructed to assess the association between recent (past 6 month) OAT enrollment and history of ever having assisted an IDU initiation with recently assisting IDU initiation. Findings were then pooled using linear mixed-effects techniques. A dynamic transmission model of IDU among the general population was developed, stratified by known factors associated with assisting IDU initiation and relevant drug use behaviors. The model was parameterized to a generic North American setting (approximately 1% PWID) and used to estimate the impact of increasing OAT coverage among PWID from baseline (approximately 21%) to 40%, 50%, and 60% on annual IDU initiation incidence and corresponding PWID population size across a decade. From Vancouver, San Diego, and Tijuana, respectively, 4.5%, 5.2%, and 4.3% of participants reported recently assisting an IDU initiation, and 49.4%, 19.7%, and 2.1% reported recent enrollment in OAT. Recent OAT enrollment was significantly associated with a 45% lower likelihood of providing recent IDU initiation assistance among PWID (relative risk [RR] 0.55 [95% CI 0.36-0.84], p = 0.006) compared to those not recently on OAT. Our dynamic model predicts a baseline mean of 1,067 (2.5%-97.5% interval [95% I 490-2,082]) annual IDU initiations per 1,000,000 individuals, of which 886 (95% I 406-1,750) are assisted by PWID. Based on our observed statistical associations, our dynamic model predicts that increasing OAT coverage from approximately 21% to 40%, 50%, or 60% among PWID could reduce annual IDU initiations by 11.5% (95% I 2.4-21.7), 17.3% (95% I 5.6-29.4), and 22.8% (95% I 8.1-36.8) and reduce the PWID population size by 5.4% (95% I 0.1-12.0), 8.2% (95% I 2.2-16.9), and 10.9% (95% I 3.2-21.8) relative to baseline, respectively, in a decade. Less impact occurs when the protective effect of OAT is diminished, when a greater proportion of IDU initiations are unassisted by PWID, and when average IDU career length is longer. The study's main limitations are uncertainty in the causal pathway between OAT enrollment and assisting with IDU initiation and the use of a simplified model of IDU initiation.

CONCLUSIONS

In addition to its known benefits on preventing HIV, hepatitis C virus (HCV), and overdose among PWID, our modeling suggests that OAT scale-up may also reduce the number of IDU initiations and PWID population size.

Opioid epidemic and liver disease

Opioid use in the United States and in many parts of the world has reached epidemic proportions. This has led to excess mortality as well as significant changes in the epidemiology of liver disease. Herein, we review the impact of the opioid epidemic on liver disease, focusing on the multifaceted impact this epidemic has had on liver disease and liver transplantation. In particular, the opioid crisis has led to a significant shift in incident hepatitis C virus infection to younger populations and to women, leading to changes in screening recommendations. Less well characterized are the potential direct and indirect hepatotoxic effects of opioids, as well as the changes in the incidence of hepatitis B virus infection and alcohol abuse that are likely rising in this population as well. Finally, the opioid epidemic has led to a significant rise in the proportion of organ donors who died due to overdose. These donors have led to an overall increase in donor numbers, but also to new considerations about the better use of donors with perceived or actual risk of disease transmission, especially hepatitis C. Clearly, additional efforts are needed to combat the opioid epidemic. Moreover, better understanding of the epidemiology and underlying pathophysiology will help to identify and treat liver disease in this high-risk population.

The contribution of injection drug use to hepatitis C virus transmission globally, regionally, and at country level: a modelling study

BACKGROUND

WHO aims to eliminate the hepatitis C virus (HCV) as a public health threat by 2030. Injection drug use is an important risk factor for HCV transmission, but its contribution to country-level and global epidemics is unknown. We estimated the contribution of injection drug use to risk for HCV epidemics globally, regionally, and at country level.

METHODS

We developed a dynamic deterministic HCV transmission model to simulate country-level HCV epidemics among people who inject drugs and the general population. Each country's model was calibrated using country-specific data from UN datasets and systematic reviews on the prevalence of HCV and injection drug use. The population attributable fraction of HCV transmission associated with injection drug use was estimated-defined here as the percentage of HCV infections prevented if additional HCV transmission due to injection drug use was removed between 2018 and 2030.

FINDINGS

The model included 88 countries (85% of the global population). The model predicted 0·23% (95% credibility interval [CrI] 0·16-0·31) of the global population were injection drug users in 2017, and 8% (5-12) of prevalent HCV infections were among people who currently inject drugs. Globally, if the increased risk for HCV transmission among people who inject drugs was removed, an estimated 43% (95% CrI 25-67) of incident HCV infections would be prevented from 2018 to 2030, varying regionally. This population attributable fraction was higher in high-income countries (79%, 95% CrI 57-97) than in countries of low and middle income (38%, 24-64) and was associated with the percentage of a country's prevalent HCV infections that are among people who inject drugs.

INTERPRETATION

Unsafe injecting practices among people who inject drugs contribute substantially to incident HCV infections globally. Any intervention that can reduce HCV transmission among people who inject drugs will have a pronounced effect on country-level incidence of HCV.

FUNDING

None.

Systematic review: economic evaluations of HCV screening in the direct-acting antivirals era

BACKGROUND

The World Health Organization estimated that 90% of the infected people need to be diagnosed and 80% need to be treated to reach the aim of hepatitis C virus (HCV) elimination by 2030. For this reason, all possible strategies to detect and treat HCV-infected people need to be carefully evaluated to implement the best one.

AIM

To review and synthesise the economic evaluations of HCV screening programs conducted in the era of direct-acting antiviral agents regimens.

METHODS

A systematic literature review was conducted until April 2018 to provide information on the costs and effectiveness of HCV screenings in direct-acting antiviral agents era. A critical assessment of the quality of economic evaluations retrieved was conducted.

RESULTS

The literature search identified 716 references; 17 of them assessed cost and effectiveness of screening programs and antiviral treatments in different populations: general population (n = 7), drug users (n = 5), high-risk populations (n = 4) and other populations (n = 3). The HCV screening and direct-acting antiviral agents treatment appear to be good value for money, both in general and high-risk populations, if a cost per quality adjusted life years of $50 000 is set as willingness to pay threshold. Some studies showed the value of including lower stage of fibrosis in the treatment selection criteria.

CONCLUSIONS

Several HCV screening strategies plus direct-acting antiviral agents treatments resulted cost-effectiveness in different populations. However, there is still need of country and population-specific evaluations within the different HCV screening and treatment strategies available, in order to assess their cost-effectiveness and sustainability and fully support an evidence-informed policy for HCV elimination.

European Association for the Study of the Liver and French hepatitis C recent guidelines: The paradigm shift

The latest Association Française pour l'Etude du Foie - French Association for Study of the Liver (AFEF) and European Association for the Study of the Liver (EASL) recommendations announce a change of paradigm, for the management of patients infected with hepatitis C virus (HCV). The AFEF recommendations focus on the elimination of HCV infection on a national level by preventing reinfection, in less than ten years. This goal involves the facilitation of patients' management in a simplified pathway by increasing screening procedures and access to pangenotypic treatments mainly in the "reservoir" population of people who inject drugs and migrants. Even in the complex pathway of patients with previous comorbidities, AFEF takes the option of a therapeutic simplification. The EASL guidelines position themselves on the state of the art with a precise description of all therapeutic options available, without separating simplified and complex pathways even if they take into account the epidemiological evolution of difficult-to-treat populations.

Social network methods for HIV case-finding among people who inject drugs in Tajikistan

INTRODUCTION

HIV testing programmes have struggled to reach the most marginalized populations at risk for HIV. Social network methods such as respondent-driven sampling (RDS) and peer-based active case-finding (ACF) may be effective in overcoming barriers to reaching these populations. We compared the client characteristics, proportion testing HIV positive (yield), and number of new cases found through two RDS strategies and an ACF approach to HIV case-finding among people who inject drugs (PWID) in Tajikistan.

METHODS

Routine programme data from adult PWID recruited to testing under the HIV Flagship Project in Tajikistan were analysed to compare client demographic and clinical characteristics across the three approaches. We also compared the number of previously untested clients, the number of new HIV cases found, and the yield across the case-finding strategies, and evaluated predictors of new HIV diagnosis using fixed-effects logistic regression.

RESULTS

From 24 October 2016 to 30 June 2017, Flagship tested 10,300 PWID for HIV, including 2143 under RDS with unrestricted waves (RDS1, yield: 1.5%), 3517 under restricted RDS (RDS2, yield: 2.6%), and 4640 under ACF (yield: 1.5%). Clients recruited under ACF were similar in age (35.8 vs. 36.8) and gender (91% vs. 90% male) to those recruited through RDS, though ACF clients were more likely to report being a first-time tester (85.1% vs. 68.3%, p < 0.001). After controlling for age, sex, previous testing history and accounting for clustering at the site level, we found that clients tested under both RDS1 (aOR: 1.74, 95% CI: 1.04 to 2.90) and RDS2 (aOR: 1.54, 95% CI: 1.11 to 2.15) had higher odds of testing newly positive for HIV relative to clients recruited through ACF. We did not find significant differences in the odds of new HIV infection between those recruited from RDS1 versus RDS2 (aOR: 1.12, 95% CI: 0.67 to 1.86).

CONCLUSIONS

RDS-based interventions resulted in higher yields and overall case-finding, especially when recruitment was restricted. However, ACF identified a higher proportion of first-time testers. To find at least 90% of PWID living with HIV in Tajikistan, it may be necessary to implement multiple case-finding approaches concurrently to maximize testing coverage.