Averting HIV infections in New York City: a modeling approach estimating the future impact of additional behavioral and biomedical HIV prevention strategies

Project PrIDE in Context: Evolution of Evaluation in the Centers for Disease Control and Prevention's Multi-Jurisdictional HIV Prevention Demonstration Projects

Over the past decade, CDC has been implementing a high-impact prevention (HIP) approach to HIV, directing funds towards activities with the greatest likelihood of reducing new infections and disparities. Corresponding to this shift, the Division of HIV/AIDS Prevention (DHAP) began funding a series of multi-site demonstration projects to provide extra support and evaluative capacity to select health departments to initiate new HIP programming, with the intention of ascertaining and sharing lessons with other health departments. In this paper, we provide context for the PrEP, Implementation, Data2Care, Evaluation (PrIDE) evaluation by describing the evolution of evaluation goals and activities across three prior demonstration projects, highlighting four areas of change: 1) integrated evaluation and program implementation; 2) local program evaluation in addition to cross-site performance monitoring; 3) prescriptive allocation of resources to support local program evaluation; and 4) expansion beyond single site program evaluation to identify effective cross-site programmatic strategies. Together, these changes reflect our own learning about achieving the greatest contribution from multi-site projects and set the stage for unique aspects of program evaluation within PrIDE. We describe these features, concluding with lessons learned from this most recent approach to structuring and supporting evaluation within CDC DHAP's health department demonstration projects.

Outcomes and costs of publicly funded patient navigation interventions to enhance HIV care continuum outcomes in the United States: A before-and-after study

BACKGROUND

In the United States, patients with HIV face significant barriers to linkage to and retention in care which impede the necessary steps toward achieving the desired clinical outcome of viral suppression. Individual-level interventions, such as patient navigation, are evidence based, effective strategies for improving care engagement. In addition, use of surveillance and clinical data to identify patients who are not fully engaged in care may improve the effectiveness and cost-effectiveness of these programs.

METHODS AND FINDINGS

We employed a pre-post design to estimate the outcomes and costs, from the program perspective, of 5 state-level demonstration programs funded under the Health Resources and Services Administration's Special Projects of National Significance Program (HRSA/SPNS) Systems Linkages Initiative that employed existing surveillance and/or clinical data to identify individuals who had never entered HIV care, had fallen out of care, or were at risk of falling out of care and navigation strategies to engage patients in HIV care. Outcomes and costs were measured relative to standard of care during the first year of implementation of the interventions (2013 to 2014). We followed patients to estimate the number and proportion of additional patients linked, reengaged, retained, and virally suppressed by 12 months after enrollment in the interventions. We employed inverse probability weighting to adjust for differences in patient characteristics across programs, missing data, and loss to follow-up. We estimated the additional costs expended during the first year of each intervention and the cost per outcome of each intervention as the additional cost per HIV additional care continuum target achieved (cost per patient linked, reengaged, retained, and virally suppressed) 12 months after enrollment in each intervention. In this study, 3,443 patients were enrolled in Louisiana (LA), Massachusetts (MA), North Carolina (NC), Virginia (VA), and Wisconsin (WI) (147, 151, 2,491, 321, and 333, respectively). Patients were a mean of 40 years old, 75% male, and African American (69%) or Caucasian (22%). At baseline, 24% were newly diagnosed, 2% had never been in HIV care, 45% had fallen out of care, and 29% were at risk of falling out of care. All 5 interventions were associated with increases in the number and proportion of patients with viral suppression [percent increase: LA = 90.9%, 95% confidence interval (CI) = 88.4 to 93.4; MA = 78.1%, 95% CI = 72.4 to 83.8; NC = 47.5%, 95% CI = 45.2 to 49.8; VA = 54.6, 95% CI = 49.4 to 59.9; WI = 58.4, 95% CI = 53.4 to 63.4]. Overall, interventions cost an additional $4,415 (range = $3,746 to $5,619), $2,009 (range = $1,516 to $2,274), $920 (range = $627 to $941), $2,212 (range = $1,789 to $2,683), and $3,700 ($2,734 to $4,101), respectively per additional patient virally suppressed. 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 patients against themselves at baseline and not against standard of care during the same time period.

CONCLUSIONS

Patient navigation programs were associated with improvements in engagement of patients in HIV care and viral suppression. Cost per outcome was minimized in states that utilized surveillance data to identify individuals who were out of care and/or those that were able to identify a larger number of patients in need of improvement at baseline. These results have the potential to inform the targeting and design of future navigation-type interventions.

Project PrIDE in context: Evolution of evaluation in the centers for disease control and prevention's multi-jurisdictional HIV prevention demonstration projects

Over the past decade, CDC has been implementing a high-impact prevention (HIP) approach to HIV, directing funds towards activities with the greatest likelihood of reducing new infections and disparities. Corresponding to this shift, the Division of HIV/AIDS Prevention (DHAP) began funding a series of multi-site demonstration projects to provide extra support and evaluative capacity to select health departments to initiate new HIP programming, with the intention of ascertaining and sharing lessons with other health departments. In this paper, we provide context for the PrEP, Implementation, Data2Care, Evaluation (PrIDE) evaluation by describing the evolution of evaluation goals and activities across three prior demonstration projects, highlighting four areas of change: 1) integrated evaluation and program implementation; 2) local program evaluation in addition to cross-site performance monitoring; 3) prescriptive allocation of resources to support local program evaluation; and 4) expansion beyond single site program evaluation to identify effective cross-site programmatic strategies. Together, these changes reflect our own learning about achieving the greatest contribution from multi-site projects and set the stage for unique aspects of program evaluation within PrIDE. We describe these features, concluding with lessons learned from this most recent approach to structuring and supporting evaluation within CDC DHAP's health department demonstration projects.

HIV supply chains in low- and middle-income countries: overview and research opportunities

Purpose

Despite HIV being reported as one of the major global health issues, availability and accessibility of HIV services and supplies remain limited, especially in low- and middle-income countries. The effective and efficient operation of HIV supply chains is critical to tackle this problem. The purpose of this paper is to give an introduction to HIV supply chains in low- and middle-income countries and identify research opportunities for the operations research/operations management (OR/OM) community.

Design/methodology/approach

First, the authors review a combination of the scientific and grey literature, including both qualitative and quantitative papers, to give an overview of HIV supply chain operations in low- and middle-income countries and the challenges that are faced by organizing such supply chains. The authors then classify and discuss the relevant OR/OM literature based on seven classification criteria: decision level, methodology, type of HIV service modeled, challenges, performance measures, real-life applicability and countries covered. Because research on HIV supply chains in low- and middle-income countries is limited in the OR/OM field, this part also includes papers focusing on HIV supply chain modeling in high-income countries.

Findings

The authors conclude this study by identifying several tendencies and gaps and by proposing future research directions for OR/OM research.

Originality/value

To the best of the authors’ knowledge, this paper is the first literature review addressing this specific topic from an OR/OM perspective.

Cost-effectiveness of HIV care coordination scale-up among persons at high risk for sub-optimal HIV care outcomes

BACKGROUND

A study of a comprehensive HIV Care Coordination Program (CCP) showed effectiveness in increasing viral load suppression (VLS) among PLWH in New York City (NYC). We evaluated the cost-effectiveness of a scale-up of the CCP in NYC.

METHODS

We incorporated observed effects and costs of the CCP into a computer simulation of HIV in NYC, comparing strategy scale-up with no implementation. The simulation combined a deterministic compartmental model of HIV transmission with a stochastic microsimulation of HIV progression, and was calibrated to NYC HIV epidemiological data from 1997 to 2009. We assessed incremental cost-effectiveness from a health sector perspective using 2017 $US, a 20-year time horizon, and a 3% annual discount rate. We explored two scenarios: (1) two-year average enrollment and (2) continuous enrollment.

RESULTS

In scenario 1, scale-up resulted in a cost-per-infection-averted of $898,104 and a cost-per-QALY-gained of $423,721. In sensitivity analyses, scale-up achieved cost-effectiveness if effectiveness increased from RR1.11 to RR1.37 or costs decreased by 41.7%. Limiting the intervention to persons with unsuppressed viral load prior to enrollment (RR1.32) attenuated the cost reduction necessary to 11.5%. In scenario 2, scale-up resulted in a cost-per-infection-averted of $705,171 and cost-per-QALY-gained of $720,970. In sensitivity analyses, scale-up achieved cost-effectiveness if effectiveness increased from RR1.11 to RR1.46 or program costs decreased by 71.3%. Limiting the intervention to persons with unsuppressed viral load attenuated the cost reduction necessary to 38.7%.

CONCLUSION

Cost-effective CCP scale-up would require reduced costs and/or focused enrollment within NYC, but may be more readily achieved in cities with lower background VLS levels.

The cost-effectiveness of oral HIV pre-exposure prophylaxis and early antiretroviral therapy in the presence of drug resistance among men who have sex with men in San Francisco

BACKGROUND

Poor adherence to either antiretroviral treatment (ART) or pre-exposure prophylaxis (PrEP) can promote drug resistance, though this risk is thought to be considerably higher for ART. In the population of men who have sex with men (MSM) in San Francisco, PrEP coverage reached 9.6% in 2014 and has continued to rise. Given the risk of drug resistance and high cost of second-line drugs, the costs and benefits of initiating ART earlier while expanding PrEP coverage remain unclear.

METHODS

We develop an infection-age-structured mathematical model and fit this model to the annual incidence of AIDS cases and deaths directly, and to resistance and demographic data indirectly. We investigate the impact of six various intervention scenarios (low, medium, or high PrEP coverage, with or without earlier ART) over the next 20 years.

RESULTS

Low (medium, high) PrEP coverage with earlier ART could prevent 22% (42%, 57%) of a projected 44,508 total new infections and 8% (26%, 41%) of a projected 18,426 new drug-resistant infections, and result in a gain of 43,649 (74,048, 103,270) QALYs over 20 years compared to the status quo, at a cost of $4745 ($78,811, $115,320) per QALY gained, respectively.

CONCLUSIONS

High PrEP coverage with earlier ART is expected to provide the greatest benefit but also entail the highest costs among the strategies considered. This strategy is cost-effective for the San Francisco MSM population, even considering the acquisition and transmission of ART-mediated drug resistance. However, without a substantial increase to San Francisco's annual HIV budget, the most advisable strategy may be initiating ART earlier, while maintaining current strategies of PrEP enrollment.

From Theory to Practice: Implementation of a Resource Allocation Model in Health Departments

OBJECTIVE

To develop a resource allocation model to optimize health departments' Centers for Disease Control and Prevention (CDC)-funded HIV prevention budgets to prevent the most new cases of HIV infection and to evaluate the model's implementation in 4 health departments.

DESIGN, SETTINGS, AND PARTICIPANTS

We developed a linear programming model combined with a Bernoulli process model that allocated a fixed budget among HIV prevention interventions and risk subpopulations to maximize the number of new infections prevented. The model, which required epidemiologic, behavioral, budgetary, and programmatic data, was implemented in health departments in Philadelphia, Chicago, Alabama, and Nebraska.

MAIN OUTCOME MEASURES

The optimal allocation of funds, the site-specific cost per case of HIV infection prevented rankings by intervention, and the expected number of HIV cases prevented.

RESULTS

The model suggested allocating funds to HIV testing and continuum-of-care interventions in all 4 health departments. The most cost-effective intervention for all sites was HIV testing in nonclinical settings for men who have sex with men, and the least cost-effective interventions were behavioral interventions for HIV-negative persons. The pilot sites required 3 to 4 months of technical assistance to develop data inputs and generate and interpret the results. Although the sites found the model easy to use in providing quantitative evidence for allocating HIV prevention resources, they criticized the exclusion of structural interventions and the use of the model to allocate only CDC funds.

CONCLUSIONS

Resource allocation models have the potential to improve the allocation of limited HIV prevention resources and can be used as a decision-making guide for state and local health departments. Using such models may require substantial staff time and technical assistance. These model results emphasize the allocation of CDC funds toward testing and continuum-of-care interventions and populations at highest risk of HIV transmission.

Cost-Effectiveness of Peer- Versus Venue-Based Approaches for Detecting Undiagnosed HIV Among Heterosexuals in High-Risk New York City Neighborhoods

INTRODUCTION

We used a computer simulation of HIV progression and transmission to evaluate the cost-effectiveness of a scale-up of 3 strategies to seek out and test individuals with undiagnosed HIV in New York City (NYC).

SETTING

Hypothetical NYC population.

METHODS

We incorporated the observed effects and costs of the 3 "seek and test" strategies in a computer simulation of HIV in NYC, comparing a scenario in which the strategies were scaled up with a 1-year implementation or a long-term implementation with a counterfactual scenario with no scale-up. The simulation combined a deterministic compartmental model of HIV transmission with a stochastic microsimulation of HIV progression, calibrated to NYC epidemiological data from 2003 to 2015. The 3 approaches were respondent-driven sampling (RDS) with anonymous HIV testing ("RDS-A"), RDS with a 2-session confidential HIV testing approach ("RDS-C"), and venue-based sampling ("VBS").

RESULTS

RDS-A was the most cost-effective strategy tested. When implemented for only 1 year and then stopped thereafter, using a societal perspective, the cost per quality-adjusted life-year (QALY) gained versus no intervention was $812/QALY, $18,110/QALY, and $20,362/QALY for RDS-A, RDS-C, and VBS, respectively. When interventions were implemented long term, the cost per QALY gained versus no intervention was cost-saving, $31,773/QALY, and $35,148/QALY for RDS-A, RDS-C, and VBS, respectively. When compared with RDS-A, the incremental cost-effectiveness ratios for both VBS and RDS-C were dominated.

CONCLUSIONS

The expansion of the RDS-A strategy would substantially reduce HIV-related deaths and new HIV infections in NYC, and would be either cost-saving or have favorable cost-effectiveness.

Improving Linkage, Retention, and Reengagement in HIV Care in 12 Metropolitan Areas

The Centers for Disease Control and Prevention developed the Enhanced Comprehensive HIV Prevention Planning (ECHPP) project to support 12 health departments' improvement of their HIV prevention and care portfolios in response to new national guidelines. We systematically analyzed 3 years of progress reports to learn how grantees put into practice local intervention strategies intended to link people to, and keep them in, HIV care. All grantees initiated seven activities to support these strategies: (1) improve surveillance data systems, (2) revise staffing duties and infrastructures, (3) update policies and procedures, (4) establish or strengthen partnerships, (5) identify persons not in care, (6) train personnel, and (7) create ways to overcome obstacles to receiving care. Factors supporting ECHPP grantee successes were thorough planning, attention to detail, and strong collaboration among health department units, and between the health department and external stakeholders. Other jurisdictions may consider adopting similar strategies when planning and enhancing HIV linkage, retention, and reengagement efforts in their areas. ECHPP experiences, lessons learned, and best practices may be relevant when applying new public health policies that affect community and health care practices jurisdiction-wide.

Betting on the fastest horse: Using computer simulation to design a combination HIV intervention for future projects in Maharashtra, India

Objective

To inform the design of a combination intervention strategy targeting HIV-infected unhealthy alcohol users in Maharashtra, India, that could be tested in future randomized control trials.

Methods

Using probabilistic compartmental simulation modeling we compared intervention strategies targeting HIV-infected unhealthy alcohol users on antiretroviral therapy (ART) in Maharashtra, India. We tested interventions targeting four behaviors (unhealthy alcohol consumption, risky sexual behavior, depression and antiretroviral adherence), in three formats (individual, group based, community) and two durations (shorter versus longer). A total of 5,386 possible intervention combinations were tested across the population for a 20-year time horizon and intervention bundles were narrowed down based on incremental cost-effectiveness analysis using a two-step probabilistic uncertainty analysis approach.

Results

Taking into account uncertainty in transmission variables and intervention cost and effectiveness values, we were able to reduce the number of possible intervention combinations to be used in a randomized control trial from over 5,000 to less than 5. The most robust intervention bundle identified was a combination of three interventions: long individual alcohol counseling; weekly Short Message Service (SMS) adherence counseling; and brief sex risk group counseling.

Conclusions

In addition to guiding policy design, simulation modeling of HIV transmission can be used as a preparatory step to trial design, offering a method for intervention pre-selection at a reduced cost.

Using the multiphase optimization strategy (MOST) to optimize an HIV care continuum intervention for vulnerable populations: a study protocol

BACKGROUND

More than half of persons living with HIV (PLWH) in the United States are insufficiently engaged in HIV primary care and not taking antiretroviral therapy (ART), mainly African Americans/Blacks and Hispanics. In the proposed project, a potent and innovative research methodology, the multiphase optimization strategy (MOST), will be employed to develop a highly efficacious, efficient, scalable, and cost-effective intervention to increase engagement along the HIV care continuum. Whereas randomized controlled trials are valuable for evaluating the efficacy of multi-component interventions as a package, they are not designed to evaluate which specific components contribute to efficacy. MOST, a pioneering, engineering-inspired framework, addresses this problem through highly efficient randomized experimentation to assess the performance of individual intervention components and their interactions. We propose to use MOST to engineer an intervention to increase engagement along the HIV care continuum for African American/Black and Hispanic PLWH not well engaged in care and not taking ART. Further, the intervention will be optimized for cost-effectiveness. A similar set of multi-level factors impede both HIV care and ART initiation for African American/Black and Hispanic PLWH, primary among them individual- (e.g., substance use, distrust, fear), social- (e.g., stigma), and structural-level barriers (e.g., difficulties accessing ancillary services). Guided by a multi-level social cognitive theory, and using the motivational interviewing approach, the study will evaluate five distinct culturally based intervention components (i.e., counseling sessions, pre-adherence preparation, support groups, peer mentorship, and patient navigation), each designed to address a specific barrier to HIV care and ART initiation. These components are well-grounded in the empirical literature and were found acceptable, feasible, and promising with respect to efficacy in a preliminary study.

METHODS/DESIGN

Study aims are: 1) using a highly efficient fractional factorial experimental design, identify which of five intervention components contribute meaningfully to improvement in HIV viral suppression, and secondary outcomes of ART adherence and engagement in HIV primary care; 2) identify mediators and moderators of intervention component efficacy; and 3) using a mathematical modeling approach, build the most cost-effective and efficient intervention package from the efficacious components. A heterogeneous sample of African American/Black and Hispanic PLWH (with respect to age, substance use, and sexual minority status) will be recruited with a proven hybrid sampling method using targeted sampling in community settings and peer recruitment (N = 512).

DISCUSSION

This is the first study to apply the MOST framework in the field of HIV prevention and treatment. This innovative study will produce a culturally based HIV care continuum intervention for the nation's most vulnerable PLWH, optimized for cost-effectiveness, and with exceptional levels of efficacy, efficiency, and scalability.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02801747 , Registered June 8, 2016.

Minority Men Who Have Sex with Men Demonstrate Increased Risk for HIV Transmission

Black and Hispanic (minority) MSM have a higher incidence of HIV than white MSM. Multiple sexual partners, being under the influence of drugs and/or alcohol during sex, having a detectable HIV-1 RNA, and non-condom use are factors associated with HIV transmission. Using data from the Veterans Aging Cohort Study, we consider minority status and sexual orientation jointly to characterize and compare these factors. White non-MSM had the lowest prevalence of these factors (p < 0.001) and were used as the comparator group in calculating odds ratios (OR). Both MSM groups were more likely to report multiple sex partners (white MSM OR 7.50; 95 % CI 5.26, 10.71; minority MSM OR 10.24; 95 % CI 7.44, 14.08), and more likely to be under the influence during sex (white MSM OR 2.15; 95 % CI 1.49, 3.11; minority MSM OR 2.94; 95 % CI 2.16, 4.01). Only minority MSM were more likely to have detectable HIV-1 RNA (OR 1.87; 95 % CI 1.12, 3.11). Both MSM groups were more likely to use condoms than white non-MSM. These analyses suggest that tailored interventions to prevent HIV transmission among minority MSM are needed, with awareness of the potential co-occurrence of risk factors.

Commentary on Des Jarlais et al. (2017): Robust public health policies as a way forward in the HIV epidemic

Effective public health policies in the context of the HIV epidemic are complex, because HIV affects many subgroups that may or may not overlap. However, there is a good case for examining how robust public health policies can positively influence disease trends and the potential lessons that can be applied to high epidemic locales.

Risk factors for self-report of not receiving an HIV test among adolescents in NYC with a history of sexual intercourse, 2013 YRBS

The Centers for Disease Control and Prevention (CDC) has previously recommended that all adolescents undergo HIV testing in the United States (US). Despite these recommendations, national HIV testing among US adolescents has remained low. This study estimated the prevalence of and identified risk factors for not receiving an HIV test among adolescents with a history of sexual intercourse in New York City (NYC), an urban area that has been greatly impacted by the HIV epidemic. Cross-sectional data on 1,199 NYC high school students who completed the 2013 NYC Youth Risk Behavior Survey were used. Modified Poisson regression models were used to assess whether demographic factors, alcohol/drug use, and sexual behaviors were associated with self-report of lack of HIV testing. In the weighted study population, about 72% were ≥16 years old, approximately 35% were African American, and nearly half were male. Sixty percent reported no history of HIV testing. In adjusted analyses, younger age, male gender, White race/ethnicity, heroin use, as well as reporting one prior sexual partner were significantly and positively associated with no prior history of HIV testing. Our findings suggest that among NYC adolescents with a history of sexual intercourse, the prevalence of HIV testing is low. HIV testing may have been low in part because of limited experience with current screening guidelines among clinicians. Furthermore, many of the adolescents identified as being more likely to not be tested, may have not been screened because of inadequate knowledge about HIV, a low perceived HIV risk, or an unstable lifestyle. Therefore, to increase HIV testing among NYC adolescents, interventions that enhance HIV knowledge among adolescents as well as interventions that promote review and application of current screening guidelines among clinicians should be implemented in NYC. Educational interventions should especially be targeted at the adolescents identified in this study.

Shifting Resources and Focus to Meet the Goals of the National HIV/AIDS Strategy: The Enhanced Comprehensive HIV Prevention Planning Project, 2010-2013

In September 2010, CDC launched the Enhanced Comprehensive HIV Prevention Planning (ECHPP) project to shift HIV-related activities to meet goals of the 2010 National HIV/AIDS Strategy (NHAS). Twelve health departments in cities with high AIDS burden participated. These 12 grantees submitted plans detailing jurisdiction-level goals, strategies, and objectives for HIV prevention and care activities. We reviewed plans to identify themes in the planning process and initial implementation. Planning themes included data integration, broad engagement of partners, and resource allocation modeling. Implementation themes included organizational change, building partnerships, enhancing data use, developing protocols and policies, and providing training and technical assistance for new and expanded activities. Pilot programs also allowed grantees to assess the feasibility of large-scale implementation. These findings indicate that health departments in areas hardest hit by HIV are shifting their HIV prevention and care programs to increase local impact. Examples from ECHPP will be of interest to other health departments as they work toward meeting the NHAS goals.

Cost Effectiveness of HIV Prevention Interventions in the U.S

INTRODUCTION

The purpose of this study was to assess and compare the cost effectiveness of current HIV prevention interventions in the U.S. using a consistent, standardized methodology.

METHODS

The cost effectiveness of common and emerging HIV biomedical and behavioral prevention interventions as delivered to men who have sex with men, injection drug users, and sexually active heterosexuals was estimated. Data on program costs, intervention efficacy, risk behaviors, and per contact transmission probabilities were collected from peer-reviewed papers and health department reports. These data were combined with 2010 national HIV incidence and prevalence surveillance data in a Bernoulli process model to estimate the reduced annual risk of HIV transmission or acquisition associated with these interventions. The cost per prevented case of HIV and the cost per saved quality-adjusted life year were then calculated. Analyses were conducted between 2014 and 2015.

RESULTS

Interventions to diagnose HIV and provide ongoing care and treatment had the lowest cost per prevented case. Among interventions targeted at specific risk groups, interventions for men who have sex with men were the most cost effective. The least cost-effective interventions typically addressed people at risk of acquiring HIV rather than those at risk of transmitting the disease.

CONCLUSIONS

HIV prevention interventions targeted at high-risk populations, those associated with the care continuum, and those that reduce the transmission risk of HIV-infected people are typically the most cost effective. Decision makers can consider these results in planning an efficient allocation of HIV prevention resources.

Economic Evaluation of Community-Based HIV Prevention Programs in Ontario: Evidence of Effectiveness in Reducing HIV Infections and Health Care Costs

Investments in community-based HIV prevention programs in Ontario over the past two and a half decades are assumed to have had an impact on the HIV epidemic, but they have never been systematically evaluated. To help close this knowledge gap, we conducted a macro-level evaluation of investment in Ontario HIV prevention programs from the payer perspective. Our results showed that, from 1987 to 2011, province-wide community-based programs helped to avert a total of 16,672 HIV infections, saving Ontario's health care system approximately $6.5 billion Canadian dollars (range 4.8-7.5B). We also showed that these community-based HIV programs were cost-saving: from 2005 to 2011, every dollar invested in these programs saved about $5. This study is an important first step in understanding the impact of investing in community-based HIV prevention programs in Ontario and recognizing the impact that these programs have had in reducing HIV infections and health care costs.

EPICE-HIV: An Epidemiologic Cost-Effectiveness Model for HIV Treatment

The goal of this research was to establish a new and innovative framework for cost-effectiveness modeling of HIV-1 treatment, simultaneously considering both clinical and epidemiological outcomes. EPICE-HIV is a multi-paradigm model based on a within-host micro-simulation model for the disease progression of HIV-1 infected individuals and an agent-based sexual contact network (SCN) model for the transmission of HIV-1 infection. It includes HIV-1 viral dynamics, CD4⁺ T cell infection rates, and pharmacokinetics/pharmacodynamics modeling. Disease progression of HIV-1 infected individuals is driven by the interdependent changes in CD4⁺ T cell count, changes in plasma HIV-1 RNA, accumulation of resistance mutations and adherence to treatment. The two parts of the model are joined through a per-sexual-act and viral load dependent probability of disease transmission in HIV-discordant couples. Internal validity of the disease progression part of the model is assessed and external validity is demonstrated in comparison to the outcomes observed in the STaR randomized controlled clinical trial. We found that overall adherence to treatment and the resulting pattern of treatment interruptions are key drivers of HIV-1 treatment outcomes. Our model, though largely independent of efficacy data from RCT, was accurate in producing 96-week outcomes, qualitatively and quantitatively comparable to the ones observed in the STaR trial. We demonstrate that multi-paradigm micro-simulation modeling is a promising tool to generate evidence about optimal policy strategies in HIV-1 treatment, including treatment efficacy, HIV-1 transmission, and cost-effectiveness analysis.

Using High-Impact HIV Prevention to Achieve the National HIV/AIDS Strategic Goals in Miami-Dade County, Florida: A Case Study

: In response to the release of the National HIV/AIDS Strategy, the Centers for Disease Control and Prevention developed the "Enhanced Comprehensive HIV Prevention Planning" project, which provided support to health departments in 12 Metropolitan Statistical Areas with the highest AIDS prevalence to strengthen local HIV programs. We describe a case study of how 1 Metropolitan Statistical Area, Miami-Dade County, developed and implemented a locally tailored plan. Examples include actions to reinforce local partnerships and identify neighborhoods with highest unmet needs, an improved condom distribution system to assist local HIV care providers, collaboration with local stakeholders to establish a new walk-in center for transgender client needs, and overcoming incompatibilities in health department and Ryan White Program computer record systems to facilitate faster and more efficient patient services. These examples show how jurisdictions both within Florida and elsewhere can create low-cost and sustainable activities tailored to improve local HIV prevention needs.

Cost and threshold analysis of positive charge, a multi-site linkage to HIV care program in the United States

Positive Charge (PC) is a linkage to HIV care initiative implemented by AIDS United with sites in New York, Chicago, Louisiana, North Carolina, and the San Francisco/Bay Area. This study employed standard methods of cost and threshold analyses, as recommended by the US Panel on Cost-effectiveness in Health and Medicine, to calculate cost-saving and cost effective thresholds of the initiative. The overall societal cost of the linkage to care programs ranged from $48,490 to $370,525. The study found that PC's five unique evidence-based linkage to care programs have relatively low costs per client served and highly achievable cost-saving and cost-effectiveness thresholds. The findings from this study suggest that HIV linkage to care programs have the potential to be a highly productive use of public health resources.

Measuring the Potential Impact of Combination HIV Prevention in Sub-Saharan Africa

A public health approach to combination HIV prevention is advocated to contain the epidemic in sub-Saharan Africa. We explore the implications of universal access to treatment along with HIV education scale-up in the region. We develop an HIV transmission model to investigate the impacts of universal access to treatment, as well as an analytical framework to estimate the effects of HIV education scale-up on the epidemic. We calibrate the model with data from South Africa and simulate the impacts of universal access to treatment along with HIV education scale-up on prevalence, incidence, and HIV-related deaths over a course of 15 years. Our results show that the impact of combined interventions is significantly larger than the summation of individual intervention impacts (super-additive property). The combined strategy of universal access to treatment and HIV education scale-up decreases the incidence rate by 74% over the course of 15 years, whereas universal access to treatment and HIV education scale up will separately decrease that by 43% and 8%, respectively. Combination HIV prevention could be notably effective in transforming HIV epidemic to a low-level endemicity. Our results suggest that in designing effective combination prevention in sub-Saharan Africa, priorities should be given to achieving universal access to treatment as quickly as possible and improving compliance to condom use.

Evaluating the impact of prioritization of antiretroviral pre-exposure prophylaxis in New York

OBJECTIVE

To compare the value and effectiveness of different prioritization strategies of pre-exposure prophylaxis (PrEP) in New York City (NYC).

DESIGN

Mathematical modelling utilized as clinical trial is not feasible.

METHODS

Using a model accounting for both sexual and parenteral transmission of HIV, we compare different PrEP prioritization strategies (PPS) with two scenarios – no PrEP and PrEP for all susceptible at-risk individuals. The PPS included PrEP for all MSM,only high-risk MSM, high-risk heterosexuals, and IDUs, and all combinations of these four strategies. Outcomes included HIV infections averted, and incremental cost effectiveness(per-infection averted) ratios. Initial assumptions regarding PrEP included a 44% reduction in HIV transmission, 50% uptake in the prioritized population and an annual cost per person of $9762. Sensitivity analyses on key parameters were conducted.

RESULTS

Prioritization to all MSM results in a 19% reduction in new HIV infections. Compared with PrEP for all persons at-risk, this PPS retains 79% of the preventive effect at 15% of the total cost. PrEP prioritized to only high-risk MSM results in a reduction in new HIV infections of 15%. This PPS retains 60% of the preventive effect at 6% of the total cost. There are diminishing returns when PrEP utilization is expanded beyond this group.

CONCLUSION

PrEP implementation is relatively cost-inefficient under our initial assumptions. Our results suggest that PrEP should first be promoted among MSM who are at particularly high risk of HIV acquisition. Further expansion beyond this group may be cost-effective, but is unlikely to be cost-saving.

Modelling in concentrated epidemics: informing epidemic trajectories and assessing prevention approaches

PURPOSE OF THE REVIEW

This review summarizes recent mathematical modelling studies conducted among key populations including MSM, people who inject drugs (PWID), and female sex workers (FSWs) in low prevalence settings used as a marker of concentrated epidemics.

RECENT FINDINGS

Most recent studies focused on MSM, Asian settings or high-income countries, studied the transmission dynamics or modelled pre-exposure prophylaxis, treatment as prevention or behavioural interventions specific to each key population (e.g., needle exchange programme or use of low-dead space syringes for PWID). Biological interventions were deemed effective and cost-effective, though still expensive, and often deemed unlikely to result in HIV elimination if used alone. Targeting high-risk individuals even within key populations improved efficiency. Some studies made innovative use of models to formally evaluate HIV prevention programmes, to interpret genetic or co-infection data, and to address methodological questions and validate epidemiological tools.

CONCLUSION

More work is needed to optimize combination prevention focusing on key populations in different settings. The gaps identified include the limited number of studies modelling drug resistance, structural interventions, treatment as prevention among FSWs, and estimating the contribution of key populations to overall transmission in different settings.