Modeling the impact of interventions along the HIV continuum of care in Newark, New Jersey

Optimizing HIV Prevention Efforts to Achieve EHE Incidence Targets

BACKGROUND

A goal of the US Department of Health and Human Services' Ending the HIV Epidemic (EHE) in the United States initiative is to reduce the annual number of incident HIV infections in the United States by 75% within 5 years and by 90% within 10 years. We developed a resource allocation analysis to understand how these goals might be met.

METHODS

We estimated the current annual societal funding [$2.8 billion (B)/yr] for 14 interventions to prevent HIV and facilitate treatment of infected persons. These interventions included HIV testing for different transmission groups, HIV care continuum interventions, pre-exposure prophylaxis, and syringe services programs. We developed scenarios optimizing or reallocating this funding to minimize new infections, and we analyzed the impact of additional EHE funding over the period 2021-2030.

RESULTS

With constant current annual societal funding of $2.8 B/yr for 10 years starting in 2021, we estimated the annual incidence of 36,000 new cases in 2030. When we added annual EHE funding of $500 million (M)/yr for 2021-2022, $1.5 B/yr for 2023-2025, and $2.5 B/yr for 2026-2030, the annual incidence of infections decreased to 7600 cases (no optimization), 2900 cases (optimization beginning in 2026), and 2200 cases (optimization beginning in 2023) in 2030.

CONCLUSIONS

Even without optimization, significant increases in resources could lead to an 80% decrease in the annual HIV incidence in 10 years. However, to reach both EHE targets, optimization of prevention funding early in the EHE period is necessary. Implementing these efficient allocations would require flexibility of funding across agencies, which might be difficult to achieve.

Modeling an integrated HIV prevention and care continuum to achieve the Ending the HIV Epidemic goals

OBJECTIVE

We sought to evaluate, which combinations of HIV prevention and care activities would have the greatest impact towards reaching the US Ending the HIV Epidemic (EHE) plan goals of HIV incidence reduction.

DESIGN

A stochastic network-based HIV transmission model for men who have sex with men (MSM), calibrated to surveillance estimates in the Atlanta area, a focal EHE jurisdiction.

METHODS

Model scenarios varied HIV screening rates under different assumptions of how HIV-negative MSM would be linked to PrEP initiation, and rates of HIV care linkage and retention for those screening positive.

RESULTS

A ten-fold relative increase in HIV screening rates (to approximately biannual screening for black and Hispanic MSM and quarterly for white MSM) would lead to 43% of infections averted if integrated with PrEP initiation. Improvements focused only on black MSM would achieve nearly the same outcome (37% of infections averted). Improvements to HIV care retention would avert 41% of infections if retention rates were improved ten-fold. If both screening and retention were jointly improved ten-fold, up to 74% of cumulative infections would be averted. Under this scenario, it would take 4 years to meet the 75% EHE goal and 12 years to meet the 90% goal for Atlanta MSM.

CONCLUSION

Reaching the EHE 75% incidence reduction goals by their target dates will require immediate and substantial improvements in HIV screening, PrEP, and ART care retention. Meeting these EHE goals in target jurisdictions like Atlanta will be possible only by addressing the HIV service needs of black MSM.

Interprofessional collaboration associated with frequency of life-saving links to HIV continuum of care services in the urban environment of Newark, New Jersey

BACKGROUND

HIV continuum of care has been used as a strategy to reduce HIV transmission rates, with timely engagement in HIV testing being the first and most critical step. This study examines interprofessional-collaboration (IPC) after controlling for agency/ provider demographics, provider training and self-efficacy as a significant predictor of how frequently HIV service providers link their clients to HIV testing.

METHODS

Multilevel binary logistic regression analysis was conducted to examine the effects of IPC on links to HIV testing while controlling for demographic and agency information, provider training, and standardized measures of providers' feelings, attitudes, and opinions about IPC. Cross-sectional data from 142 providers in 13 agencies offering treatment and prevention services for HIV and substance-use disorders were collected via a survey.

RESULTS

Those who scored higher on the IPC scale reported significantly higher rates of linkages to HIV testing. Compared to the null model (i.e., no predictor model), the final multilevel binary logistic regression model showed a significantly improved likelihood of linkage to HIV testing by 11.4%, p. < .05. The final model correctly classified 90.2% of links to HIV testing. Providers in agencies with smaller budgets and in agencies offering substance use disorder services were more likely to link clients to HIV testing. Younger providers who received HIV training were also more likely to link clients to HIV testing.

CONCLUSIONS

Findings suggest IPC training as a potential strategy to improve linkages to HIV testing for clients at risk for HIV infection. Future research is recommended to identify specific areas of IPC that might have differential effects on links to HIV testing.

Bringing a health systems modelling approach to complex evaluations: multicountry applications in HIV, TB and malaria

INTRODUCTION

Understanding how to deliver interventions more effectively is a growing emphasis in Global Health. Simultaneously, health system strengthening is a key component to improving delivery. As a result, it is challenging to evaluate programme implementation while reflecting real-world complexity. We present our experience in using a health systems modelling approach as part of a mixed-methods evaluation and describe applications of these models.

METHODS

We developed a framework for how health systems translate financial inputs into health outcomes, with in-country and international experts. We collated available data to measure framework indicators and developed models for malaria in Democratic Republic of the Congo (DRC), and tuberculosis in Guatemala and Senegal using Bayesian structural equation modelling. We conducted several postmodelling analyses: measuring efficiency, assessing bottlenecks, understanding mediation, analysing the cascade of care and measuring subnational effectiveness.

RESULTS

The DRC model indicated a strong relationship between shipment of commodities and utilisation thereof. In Guatemala, the strongest model coefficients were more evenly distributed. Results in Senegal varied most, but pathways related to community care had the strongest relationships. In DRC, we used model results to estimate the end-to-end cost of delivering commodities. In Guatemala, we used model results to identify potential bottlenecks and understand mediation. In Senegal, we used model results to identify potential weak links in the cascade of care, and explore subnationally.

CONCLUSION

This study demonstrates a complementary modelling approach to traditional evaluation methods. Although these models have limitations, they can be applied in a variety of ways to gain greater insight into implementation and functioning of health service delivery.

HIV Testing With and Without a Clinical Consultation Among Men Who Have Sex With Men: A Randomized Controlled Trial

BACKGROUND

Increasing the frequency of HIV testing among men who have sex with men (MSM) maximizes the preventive effect of antiretroviral therapy, by reducing time to diagnosis and treatment.

SETTING

Melbourne Sexual Health Centre, Australia.

METHODS

This randomized controlled trial evaluated whether access to testing, without seeing a clinician would increase testing frequency. MSM attending for HIV testing between July 2014 and April 2015 were randomized in 1:1 ratio to the intervention arm (access to HIV and syphilis testing at 300 pathology centers, without requiring consultations) or the control arm (consultation at every test), without blinding. The primary outcome was the incidence of HIV testing over 12 months.

RESULTS

Of 443 men referred, 422 were randomized, 3 HIV positives at baseline were excluded, and 419 were analyzed. Of 208 control, 202 (97.1%) and 200 (94.8%) of 211 intervention group members were followed to 12 months. The intervention group had 453 tests in 205.6 person-years, incidence rate was 2.2 (95% confidence interval [CI]: 2.0 to 2.4) tests per year. The control group had 432 tests during 204.0 person-years, incidence rate was 2.1 (95% CI: 1.9 to 2.3) tests per year, and incidence rate ratio was 1.04 (95% CI: 0.89 to 1.2; P = 0.63). The annual rate of consultations was as follows: intervention, 1.61 (95% CI: 1.44 to 1.79); controls, 2.12 (95% CI: 1.92 to 2.33); rate ratio, 0.76 (95% CI: 0.65 to 0.88; P = 0.0001). There was no difference in quality of life scores (P = 0.61).

CONCLUSIONS

MSM permitted HIV and syphilis testing outside of clinical consultations did not test more frequently than controls but had 24% fewer consultations, reducing service demand.

TRIAL REGISTRATION

ACTRN12614000760673.

Structural Design and Data Requirements for Simulation Modelling in HIV/AIDS: A Narrative Review

Born out of a necessity for fiscal sustainability, simulation modeling is playing an increasingly prominent role in setting priorities for combination implementation strategies for HIV treatment and prevention globally. The design of a model and the data inputted into it are central factors in ensuring credible inferences. We executed a narrative review of a set of dynamic HIV transmission models to comprehensively synthesize and compare the structural design and the quality of evidence used to support each model. We included 19 models representing both generalized and concentrated epidemics, classified as compartmental, agent-based, individual-based microsimulation or hybrid in our review. We focused on four structural components (population construction; model entry, exit and HIV care engagement; HIV disease progression; and the force of HIV infection), and two analytical components (model calibration/validation; and health economic evaluation, including uncertainty analysis). While the models we reviewed focused on a variety of individual interventions and their combinations, their structural designs were relatively homogenous across three of the four focal components, with key structural elements influenced by model type and epidemiological context. In contrast, model entry, exit and HIV care engagement tended to differ most across models, with some health system interactions-particularly HIV testing-not modeled explicitly in many contexts. The quality of data used in the models and the transparency with which the data was presented differed substantially across model components. Representative and high-quality data on health service delivery were most commonly not accessed or were unavailable. The structure of an HIV model should ideally fit its epidemiological context and be able to capture all efficacious treatment and prevention services relevant to a robust combination implementation strategy. Developing standardized guidelines on evidence syntheses for health economic evaluation would improve transparency and help prioritize data collection to reduce decision uncertainty.

Dynamic modeling approaches to characterize the functioning of health systems: A systematic review of the literature

Universal Health Coverage (UHC) is one of the targets for the United Nations Sustainable Development Goal 3. The impetus for UHC has led to an increased demand for time-sensitive tools to enhance our knowledge of how health systems function and to evaluate impact of system interventions. We define the field of "health system modeling" (HSM) as an area of research where dynamic mathematical models can be designed in order to describe, predict, and quantitatively capture the functioning of health systems. HSM can be used to explore the dynamic relationships among different system components, including organizational design, financing and other resources (such as investments in resources and supply chain management systems) - what we call "inputs" - on access, coverage, and quality of care - what we call "outputs", toward improved health system "outcomes", namely increased levels and fairer distributions of population health and financial risk protection. We undertook a systematic review to identify the existing approaches used in HSM. We identified "systems thinking" - a conceptual and qualitative description of the critical interactions within a health system - as an important underlying precursor to HSM, and collated a critical collection of such articles. We then reviewed and categorized articles from two schools of thoughts: "system dynamics" (SD)" and "susceptible-infected-recovered-plus" (SIR+). SD emphasizes the notion of accumulations of stocks in the system, inflows and outflows, and causal feedback structure to predict intended and unintended consequences of policy interventions. The SIR + models link a typical disease transmission model with another that captures certain aspects of the system that impact the outcomes of the main model. These existing methods provide critical insights in informing the design of HSM, and provide a departure point to extend this research agenda. We highlight the opportunity to advance modeling methods to further understand the dynamics between health system inputs and outputs.

Delivery of HIV Antiretroviral Therapy Adherence Support Services by HIV Care Providers in the United States, 2013 to 2014

BACKGROUND

Little is known about clinicians' adoption of recommendations of the International Association of Providers of AIDS Care and others for supporting adherence to antiretroviral therapy (ART).

METHODS

We surveyed a probability sample of US HIV care providers to estimate the percentage offering 3 ART adherence support services to most or all patients and assessed the characteristics of providers offering all 3 services (comprehensive support) to most or all patients.

RESULTS

Almost all providers (95.5%) discussed ART adherence at every visit, 60.1% offered advice about tools to increase adherence, 53.5% referred nonadherent patients for supportive services, and 42.8% provided comprehensive support. Nurse practitioners were more likely to offer comprehensive support as were providers who practiced at Ryan White HIV/AIDS Program-funded facilities, provided primary care, or started caring for HIV-infected patients within 10 years.

CONCLUSION

Less than half of HIV care providers offered comprehensive ART adherence support. Certain subgroups may benefit from interventions to increase delivery of adherence support.

The effect of prevention methods on reducing sexual risk for HIV and their potential impact on a large-scale: a literature review

A spectrum of diverse prevention methods that offer high protection against HIV has posed the following challenge: how can national AIDS policies with high coverage for prevention and treatment make the best use of new methods so as to reverse the current high, and even rising, incidence rates among specific social groups? We conducted a narrative review of the literature to examine the prevention methods and the structural interventions that can have a higher impact on incidence rates in the context of socially and geographically concentrated epidemics. Evidence on the protective effect of the methods against sexual exposure to HIV, as well as their limits and potential, is discussed. The availability and effectiveness of prevention methods have been hindered by structural and psychosocial barriers such as obstacles to adherence, inconsistent use over time, or only when individuals perceive themselves at higher risk. The most affected individuals and social groups have presented limited or absence of use of methods as this is moderated by values, prevention needs, and life circumstances. As a result, a substantial impact on the epidemic cannot be achieved by one method alone. Programs based on the complementarity of methods, the psychosocial aspects affecting their use and the mitigation of structural barriers may have the highest impact on incidence rates, especially if participation and community mobilization are part of their planning and implementation.

Missed Testing Opportunities for HIV Screening and Early Diagnosis in an Urban Tertiary Care Center

Newark, New Jersey, is disproportionally affected by HIV with one of the highest prevalence rates in the United States. Rutgers New Jersey Medical School is a major healthcare provider to Newark's underserved population and has implemented a HIV testing program that can diagnose and link newly diagnosed individuals to care. We conducted a retrospective chart review of all new patients seen in the Infectious Disease Practice from January 1, 2013, to December 31, 2014, to determine the proportion of patients with a missed testing opportunity (MTO) (patients with a new HIV diagnosis with an encounter at the institution in the 1 year prior to their first appointment). 117 newly diagnosed patients were identified. 36 (31%) had at least one MTO. A total of 34 (29%) of newly diagnosed patients had AIDS at presentation and 17% had CD4 counts of 50 cells/μL (p value 0.5). The two most common locations of a missed testing opportunity were the hospital ED (45%) and subspecialty clinics (37%). This study demonstrates that, even in a high prevalence institution with HIV counseling, testing, and referral service, HIV screening is lacking at multiple points of care and patients are missing opportunities for earlier diagnosis and treatment.

The impact of HCV therapy in a high HIV-HCV prevalence population: A modeling study on people who inject drugs in Ho Chi Minh City, Vietnam

BACKGROUND

Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) coinfection is a major global health problem especially among people who inject drugs (PWID), with significant clinical implications. Mathematical models have been used to great effect to shape HIV care, but few have been proposed for HIV/HCV.

METHODS

We constructed a deterministic compartmental ODE model that incorporated layers for HIV disease progression, HCV disease progression and PWID demography. Antiretroviral therapy (ART) and Methadone Maintenance Therapy (MMT) scale-ups were modeled as from 2016 and projected forward 10 years. HCV treatment roll-out was modeled beginning in 2026, after a variety of MMT scale-up scenarios, and projected forward 10 years.

RESULTS

Our results indicate that scale-up of ART has a major impact on HIV though not on HCV burden. MMT scale-up has an impact on incidence of both infections. HCV treatment roll-out has a measurable impact on reductions of deaths, increasing multifold the mortality reductions afforded by just ART/MMT scale-ups.

CONCLUSION

HCV treatment roll-out can have major and long-lasting effects on averting PWID deaths on top of those averted by ART/MMT scale-up. Efficient intervention scale-up of HCV alongside HIV interventions is critical in Vietnam.

Association between engagement in-care and mortality in HIV-positive persons

Objective:

To assess associations between engagement in-care and future mortality.

Design:

UK-based observational cohort study.

Methods:

HIV-positive participants with more than one visit after 1 January 2000 were identified. Each person-month was classified as being in or out-of-care based on the dates of the expected and observed next care visits. Cox models investigated associations between mortality and the cumulative proportion of months spent in-care (% IC, lagged by 1 year), and cumulative %IC prior to antiretroviral therapy (ART) in those attending clinic for more than 1 year, with adjustment for age, CD4⁺/viral load, year, sex, infection mode, ethnicity, and receipt/type of ART.

Results:

The 44 432 individuals (27.8% women; 50.5% homosexual, 28.9% black African; median age 36 years) were followed for a median of 5.5 years, over which time 2279 (5.1%) people died. Higher %IC was associated with lower mortality both before [relative hazard 0.91 (95% confidence interval 0.88–0.95)/10% higher, P = 0.0001] and after [0.90 (0.87–0.93), P = 0.0001] adjustment. Adjustment for future CD4⁺ changes revealed that the association was explained by poorer CD4⁺ cell counts in those with lower %IC. In total 8730 participants under follow-up for more than 1 year initiated ART of whom 237 (2.7%) died. Higher values of %IC prior to ART initiation were associated with a reduced risk of mortality before [0.29 (0.17–0.47)/10%, P = 0.0001] and after [0.36 (0.21–0.61)/10%, P = 0.0002] adjustment; the association was again explained by poorer post-ART CD4⁺/ viral load in those with lower pre-ART %IC.

Conclusions:

Higher levels of engagement in-care are associated with reduced mortality at all stages of infection, including in those who initiate ART.

Using Population-Size Estimation and Cross-sectional Survey Methods to Evaluate HIV Service Coverage Among Key Populations in Burkina Faso and Togo

OBJECTIVES

The objective of our study was to measure progress toward the UNAIDS 90-90-90 HIV care targets among key populations in urban areas of 2 countries in West Africa: Burkina Faso and Togo.

METHODS

We recruited female sex workers (FSWs) and men who have sex with men (MSM) through respondent-driven sampling. From January to July 2013, 2738 participants were enrolled, tested for HIV, and completed interviewer-administered surveys. We used population-size estimation methods to calculate the number of people who were engaged in the HIV continuum of care.

RESULTS

HIV prevalence ranged from 0.6% (2 of 329) of MSM in Kara, Togo, to 32.9% (115 of 350) of FSWs in Bobo Dioulasso, Burkina Faso. Of those confirmed to be HIV infected, a range of 0.0% (0 of 2) of MSM in Kara to 55.7% (64 of 115) of FSWs in Bobo Dioulasso were using ART. Based on population estimates, the percentage gap between HIV-infected people who should be using ART (per the 90-90-90 targets) and those who reported using ART ranged from 31.5% among FSWs in Bobo Dioulasso to 100.0% among MSM in Kara.

CONCLUSIONS

HIV service coverage among MSM and FSWs in Burkina Faso and Togo was low in 2013. Interventions for improving engagement of these at-risk populations in the HIV continuum of care should include frequent, routine HIV testing and linkage to evidence-based HIV treatment services. Population-size estimates can be used to inform governments, policy makers, and funding agencies about where elements of HIV service coverage are most needed.

Sources of HIV infection among men having sex with men and implications for prevention

New HIV diagnoses among men having sex with men (MSM) have not decreased appreciably in most countries, even though care and prevention services have been scaled up substantially in the past 20 years. To maximize the impact of prevention strategies, it is crucial to quantify the sources of transmission at the population level. We used viral sequence and clinical patient data from one of Europe's nationwide cohort studies to estimate probable sources of transmission for 617 recently infected MSM. Seventy-one percent of transmissions were from undiagnosed men, 6% from men who had initiated antiretroviral therapy (ART), 1% from men with no contact to care for at least 18 months, and 43% from those in their first year of infection. The lack of substantial reductions in incidence among Dutch MSM is not a result of ineffective ART provision or inadequate retention in care. In counterfactual modeling scenarios, 19% of these past cases could have been averted with current annual testing coverage and immediate ART to those testing positive. Sixty-six percent of these cases could have been averted with available antiretrovirals (immediate ART provided to all MSM testing positive, and preexposure antiretroviral prophylaxis taken by half of all who test negative for HIV), but only if half of all men at risk of transmission had tested annually. With increasing sequence coverage, molecular epidemiological analyses can be a key tool to direct HIV prevention strategies to the predominant sources of infection, and help send HIV epidemics among MSM into a decisive decline.

Sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays or HIV RNA tests

OBJECTIVE

Determine the sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays (EIA) or nucleic acid amplification tests (NAAT) in clinical settings.

DESIGN

Systematic review and meta-analysis.

METHODS

Medline, PubMed, Embase, Cochrane Controlled Trials Register, Cochrane reviews and Cumulative Index to Nursing and Allied Health Literature were searched until 14 July 2015 for studies of adults comparing point-of-care HIV rapid tests to fourth-generation HIV EIA antibody/p24 antigen or HIV NAAT.

RESULTS

From 953 titles, 18 studies were included, involving 110 122 HIV rapid test results. Compared with EIA, the estimated sensitivity (random effects) of HIV rapid tests was 94.5% [95% confidence interval (CI): 87.4-97.7]. Compared with NAAT, the sensitivity of HIV rapid tests was 93.7% (95% CI: 88.7-96.5). The sensitivity of HIV rapid tests in high-income countries was 85.7% (95% CI: 81.9-88.9) and in low-income countries was 97.7% (95% CI: 95.2-98.9) compared with either EIA or NAAT (P < 0.01 for difference between settings). Proportions of antibody negative acute infections were 13.6 (95% CI: 10.1-18.0) and 4.7% (95% CI: 2.8-7.7) in studies from high-income and low-income countries, respectively (P < 0.01).

CONCLUSION

In clinical settings, HIV rapid tests were less sensitive in high-income countries compared with low-income countries, missing about one in seven infections, possibly because of the larger proportion of acute infections in targeted populations. This suggests that in high-income countries, HIV rapid tests should be used in combination with fourth-generation EIA or NAAT tests, except in special circumstances. Prospective Registration of Systematic Reviews registration number CRD42015020154.Supplementary video link: http://links.lww.com/QAD/A924.

Factors Associated with Missed Psychiatry Visits in an Urban HIV Clinic

Psychiatric co-management is often required in HIV primary care. While rates and clinical impact of linkage and retention in HIV are well explored, fewer investigations focus specifically on linkage to psychiatry. In this investigation, we evaluate factors associated with linkage to psychiatric services using a retrospective cohort study of HIV-infected patients during a two-year observation period. Descriptive statistics depict patient characteristics, and logistic regression models were fit to evaluate factors associated with failure to establish care at the co-located psychiatry clinic following referral from HIV provider. Of 370 referred, 23 % did not attend a scheduled psychiatry appointment within 6 months of initial referral. In multivariable analysis, Non-white race, younger age, non-suppressed viral load, and increased wait time to appointment (in days) were associated with failure to attend. Further exploration of barriers that contribute to disparate linkage to psychiatric care may inform future interventions to improve HIV outcomes in this population.

HIV Care Continuum for HIV-Infected Emergency Department Patients in an Inner-City Academic Emergency Department

STUDY OBJECTIVE

The recently released HIV Care Continuum Initiative is a cornerstone of the National AIDS Strategy and a model for improving care for those living with HIV. To our knowledge, there are no studies exploring the entirety of the HIV Care Continuum for patients in the emergency department (ED). We determine gaps in the HIV Care Continuum to identify potential opportunities for improved care for HIV-infected ED patients.

METHODS

A mixed-methods approach was used in 1 inner-city ED in 2007. Data elements were derived from an identity-unlinked HIV seroprevalence study, an ongoing nontargeted HIV screening program, and a structured survey of known HIV-positive ED patients.

RESULTS

Identity-unlinked testing of 3,417 unique ED patients found that 265 (7.8%) were HIV positive. Of patients testing HIV positive, 73% had received a previous diagnosis (based on self-report, chart review, or presence of antiretrovirals in serum), but only 61% were recognized by the clinician as being HIV infected (based on self-report or chart review). Of patients testing positive, 43% were linked to care, 39% were retained in care, 27% were receiving antiretrovirals, 26% were aware of their receiving antiretroviral treatment, 22% were virally suppressed, and only 9% were self-aware of their viral suppression.

CONCLUSION

To our knowledge, this study is the first to quantify gaps in HIV care for an ED patient population, with the HIV Care Continuum as a framework. Our findings identified distinct phases (ie, testing, provider awareness of HIV diagnosis, and linkage to care) in which the greatest opportunities for intervention exist, if appropriate resources were allocated. This schema could serve as a model for other indolent treatable diseases frequently observed in EDs, where continuity of care is critical.

Addressing the challenges of the HIV continuum of care in high-prevalence cities in the United States

In summary, addressing the challenges of the HIV care continuum is critical so that the goals of the NHAS can be achieved. CDC is working closely with federal partners, public health departments, and communities throughout the United States on multiple surveillance, programmatic, and research initiatives to inform and improve outcomes along the HIV care continuum. Currently, a large number of research projects are being conducted to describe the care continuum in various populations, assess and model the impact of interventions, and monitor the quality of care. To contribute to this knowledge base, NIH is working with its academic partners to support research that will inform the optimization of HIV treatment and prevention programs. As part of this focus, the CFAR/APC HIV Continuum of Care Working Group was formed to encourage communication between academic investigators and their local DOHs and to support joint research initiatives that are both timely and relevant to their own cities and environments. Finally, the results presented in this supplement may have implications for jurisdictions beyond those in which the studies were conducted.

The impact of transfer patients on the local cascade of HIV care continuum

BACKGROUND

The Cascade of Care (COC) visualizes stages of HIV care progression within a population. It is predicated on a local population model and thus may not address the impact on the COC of HIV-experienced individuals diagnosed and cared for elsewhere who move into the area.

METHODS

All individuals with a confirmed HIV+ test in Calgary, Canada, between January 1, 2006, and January 1, 2013 were included. Individuals were categorized as "local" if diagnosed within the area, or "transfer" if diagnosed elsewhere. Subgroups were separately placed within the COC and then aggregated.

RESULTS

Of 1019 new cases, 47% were transfers. Transfer patients were more likely female (35% vs. 23%; P < 0.01), non-white (61% vs. 46%; P < 0.001), heterosexual (56% vs. 38%; P < 0.001), and have higher CD4 counts (400 vs. 282/mm) with undetectable viremia in 57% [63% on antiretroviral therapy (ART)] at baseline. Engagement was higher at every stage for transfer patients: 94% of transfer vs. 92% of local patients linked to HIV care, 90% vs. 76% (P < 0.001) were retained, 86% vs. 67% (P < 0.001) received ART, and at study's end, 75% vs. 58% (P < 0.001) had undetectable viremia. When patients were aggregated, linkage increased by 1%, retention by 6%, patient use of ART by 8%, and patients with viral suppression by 7%.

CONCLUSIONS

The COC of local and transfer patients differs so significantly that both need to be considered separately in measuring COC, adding a previously under-recognized level of complexity. Use of aggregate COC without considering different levels of engagement could lead to imprecise information for public health initiatives and program metrics.

HIV self-testing among key populations: an implementation science approach to evaluating self-testing

OBJECTIVES

To review methods for measuring HIV self-testing (HIVST) among key populations, including both conventional approaches and implementation science approaches.

METHODS

We reviewed the literature on evaluating HIVST among key populations.

RESULTS

Simple HIV self-tests have already entered markets in several regions, but metrics required to demonstrate the benefits and costs of HIVST remain simplistic. Conventional measurements of sensitivity, specificity, acceptability, and behavioural preferences must be supplemented with richer implementation science measurement tools and innovative research designs in order to capture data on the following components: how self-testing affects subsequent linkage to confirmatory testing, preventive services and onward steps in the HIV continuum of care; how self-testing can be marketed to reach untested subpopulations; and how self-testing can be sustained based on overarching organisational and financial models. We outline an implementation science research agenda that incorporates these components, drawing from evaluation study designs focused on HIVST and testing in general.

CONCLUSION

HIVST holds great promise for key populations, but must be guided by implementation research to inform programmes and scale up.

Modeling the implementation of universal coverage for HIV treatment as prevention and its impact on the HIV epidemic

The Joint United Nations Programme on HIV/AIDS (UNAIDS) recently updated its global targets for antiretroviral therapy (ART) coverage for HIV-positive persons under which 90 % of HIV-positive people are tested, 90 % of those are on ART, and 90 % of those achieve viral suppression. Treatment policy is moving toward treating all HIV-infected persons regardless of CD4 cell count-otherwise known as treatment as prevention-in order to realize the full therapeutic and preventive benefits of ART. Mathematical models have played an important role in guiding the development of these policies by projecting long-term health impacts and cost-effectiveness. To guide future policy, new mathematical models must consider the barriers patients face in receiving and taking ART. Here, we describe the HIV care cascade and ART delivery supply chain to examine how mathematical modeling can provide insight into cost-effective strategies for scaling-up ART coverage in sub-Saharan Africa and help achieve universal ART coverage.