Relative effects of antiretroviral therapy and harm reduction initiatives on HIV incidence in British Columbia, Canada, 1996-2013: a modelling study

Cost-effectiveness of internet-based HIV screening among gay, bisexual and other men who have sex with men (GBMSM) in Metro Vancouver, Canada

BACKGROUND

GetCheckedOnline is an internet-based screening service aiming to increase HIV testing among gay, bisexual and other men who have sex with men (GBMSM). We assessed the cost-effectiveness of GetCheckedOnline in its first implementation phase at different uptake scenarios compared to clinic-based screening services alone in Metro Vancouver, Canada.

METHODS

From a healthcare payer's perspective, our cost-utility analysis used an established dynamic GBMSM HIV compartmental model estimating the probability of acquiring HIV, progressing through diagnosis, disease stages and treatment over a 30-year time horizon. The base case scenario assumed 4.7% uptake of GetCheckedOnline in 2016 (remainder using clinic-based services), with 74% of high-risk and 44% of low-risk infrequent testers becoming regular testers in five years. Scenario analyses tested increased GetCheckedOnline uptake to 10% and 15%.

RESULTS

The cost per test for GetCheckedOnline was $29.40 compared to clinic-based services $56.92. Compared with clinic-based screening services, the projected increase in testing frequency with 4.7% uptake of GetCheckedOnline increased the costs by $329,600 (95% Credible Interval: -$498,200, $571,000) and gained 4.53 (95%CrI: 0, 9.20) quality-adjusted life years (QALYs) in a 30-year time horizon. The probability of GetCheckedOnline being cost-effective was 34% at the threshold of $50,000 per QALY, and increased to 73% at the threshold of $100,000 per QALY. The results were consistent in the other uptake scenarios. The probability of GetCheckedOnline being cost-effective became 80% at the threshold of $50,000 per QALY if assuming 5-year time horizon.

CONCLUSIONS

GetCheckedOnline is almost half the cost of clinic-based services on a per-test basis. However, increased access to testing should be balanced with risk profiles of patients to ensure the implementation can be a cost-effective strategy for increasing HIV screening among GBMSM in Metro Vancouver. Additional analyses are needed to understand the impact of internet-based screening including screening for other STIs and in other populations.

Process description of developing HIV prevention monitoring indicators for a province-wide pre-exposure prophylaxis (PrEP) program in British Columbia, Canada

In 2018, the pre-exposure prophylaxis (PrEP) program was initiated in British Columbia (BC), Canada, providing PrEP at no cost to qualifying residents. This observational study discussed the steps to develop key evidence-based monitoring indicators and their calculation using real-time data. The indicators were conceptualized, developed, assessed and approved by the Technical Monitoring Committee of representatives from five health authority regions in BC, the BC Ministry of Health, the BC Centre for Disease Control, and the BC Centre for Excellence in HIV/AIDS. Indicator development followed the steps adopted from the United States Centers for Disease Control and Prevention framework for program evaluation in public health. The assessment involved eight selection criteria: data quality, indicator validity, existing scientific evidence, indicator informativeness, indicator computing feasibility, clients' confidentiality maintenance capacity, indicator accuracy, and administrative considerations. Clients' data from the provincial-wide PrEP program (January 2018-December 2020) shows the indicators' calculation. The finalized 14 indicators included gender, age, health authority, new clients enrolled by provider type and by the health authority, new clients dispensed PrEP, clients per provider, key qualifying HIV risk factor(s), client status, PrEP usage type, PrEP quantity dispensed, syphilis and HIV testing and incident cases, and adverse drug reaction events. Cumulative clients' data (n = 6966; 99% cis-gender males) identified an increased new client enrollment and an unexpected drop during the COVID-19 pandemic. About 80% dispensed PrEP from the Vancouver Coastal health authority. The HIV incidence risk index for men who have sex with men score ≥10 was the most common qualifying risk factor. The framework we developed integrating indicators was applied to monitor our PrEP program, which could help reduce the public health impact of HIV.

Maintenance on extended-release naltrexone is associated with reduced injection opioid use among justice-involved persons with opioid use disorder

INTRODUCTION

Opioid use disorder (OUD) and injection drug use (IDU) place justice-involved individuals at increased risk for acquiring or transmitting HIV or hepatitis C virus (HCV). Methadone and buprenorphine have been associated with reduced opioid IDU; however, the effect of extended-release naltrexone (XR-NTX) on this behavior is incompletely studied.

METHODS

This study examined injection opioid use and shared injection equipment behavior from a completed double-blind placebo-controlled trial of XR-NTX among 88 justice-involved participants with HIV and OUD. Changes in participants' self-reported daily injection opioid use and shared injection equipment was evaluated pre-incarceration, during incarceration, and monthly post-release for 6 months. The study also assessed differences in time to first opioid injection post-release. The research team performed intention to treat and "as treated" (high treatment versus low treatment) analyses.

RESULTS

Fifty-eight of 88 participants (69.5 %) endorsed IDU and 26 (29.5 %) reported sharing injection equipment in the 30 days pre-incarceration; 2 participants (2.2 %) reported IDU during incarceration; 19 (21.6 %) reported IDU one month post-release from prison or jail. Fifty-four (61.4 %) participants had an HIV RNA below 200 copies/mL and 62 (70.5 %) were baseline HCV antibody positive. The 6-month follow-up rate was 49.5 % and 50.5 % for those who received XR-NTX and placebo, respectively, which was not significantly different (p = 0.822). Participants in the XR-NTX and placebo groups had similar low mean opioid injection use post-release and time to first injection opioid use in the Intention-to-treat analysis. In the as-treated analysis, participants in the high treatment group had significantly lower mean proportion of days injecting opioids (13.8 % high treatment versus 22.8 % low treatment, p = 0.02) by month 1, which persisted up to 5 months post-release (0 % high treatment vs 24.3 % low treatment, p < 0.001) and experienced a longer time to first opioid injection post-release (143.8 days high treatment vs 67.4 days low treatment, p < 0.001).

CONCLUSIONS

Injection opioid use was low during incarceration and remained low post-release in this justice-involved population. Retention on XR-NTX was associated with reduced intravenous opioid use, which has important implications for reducing transmission of HIV and HCV.

The role of depression in secondary HIV transmission among people who inject drugs in Vietnam: A mathematical modeling analysis

Background

Among people who inject drugs (PWID), depression burden is high and may interfere with HIV prevention efforts. Although depression is known to affect injecting behaviors and HIV treatment, its overall impact on HIV transmission has not been quantified. Using mathematical modeling, we sought to estimate secondary HIV transmissions and identify differences by depression among PWID.

Methods

We analyzed longitudinal data from 455 PWID living with HIV in Vietnam during 2009–2013. Using a Bernoulli process model with individual-level viral load and behavioral data from baseline and 6-month follow-up visits, we estimated secondary HIV transmission events from participants to their potentially susceptible injecting partners. To evaluate differences by depression, we compared modeled transmissions per 1,000 PWID across depressive symptom categories (severe, mild, or no symptoms) in the three months before each visit.

Results

We estimated a median of 41.2 (2.5^th, 97.5^th percentiles: 33.2–49.2) secondary transmissions from all reported acts of sharing injection equipment with 833 injecting partners in the three months before baseline. Nearly half (41%) of modeled transmissions arose from fewer than 5% of participants in that period. Modeled transmissions per 1,000 PWID in that period were highest for severe depressive symptoms (100.4, 80.6–120.2) vs. mild (87.0, 68.2–109.4) or no symptoms (78.9, 63.4–94.1). Transmission estimates fell to near-zero at the 6-month visit.

Conclusions

Secondary transmissions were predicted to increase with depression severity, although most arose from a small number of participants. Our findings suggest that effective depression interventions could have the important added benefit of reducing HIV transmission among PWID.

M2HepPrEP: study protocol for a multi-site multi-setting randomized controlled trial of integrated HIV prevention and HCV care for PWID

Background

Opioid use is escalating in North America and comes with a multitude of health consequences, including HIV and hepatitis C virus (HCV) outbreaks among persons who inject drugs (PWID). HIV pre-exposure prophylaxis (PrEP) and HCV treatment regimens have transformative potential to address these co-occurring epidemics. Evaluation of innovative multi-modal approaches, integrating harm reduction, opioid agonist therapy (OAT), PrEP, and HCV treatment is required. The aim of this study is to assess the effectiveness of an on-site integrated care model where delivery of PrEP and HCV treatment for PWID takes places at syringe service programs (SSP) and OAT programs compared with referring PWID to clinical services in the community through a patient navigation model and to examine how structural factors interact with HIV prevention adherence and HCV treatment outcomes.

Methods

The Miami-Montreal Hepatitis C and Pre-Exposure Prophylaxis trial (M²HepPrEP) is an open-label, multi-site, multi-center, randomized, controlled, superiority trial with two parallel treatment arms. A total of 500 persons who injected drugs in the prior 6 months and are eligible for PrEP will be recruited in OAT clinics and SSP in Miami, FL, and Montréal, Québec. Participants will be randomized to either on-site care, with adherence counseling, or referral to off-site clinics assisted by a patient navigator. PrEP will be offered to all participants and HCV treatment to those HCV-infected. Co-primary endpoints will be (1) adherence to pre-exposure prophylaxis medication at 6 months post-randomization and (2) HCV sustained virological response (SVR) 12 weeks post-treatment completion among participants who were randomized within the HCV stratum. Up to 100 participants will be invited to participate in a semi-structured interview regarding perceptions of adherence barriers and facilitators, after their 6-month assessment. A simulation model-based cost-effectiveness analysis will be performed to determine the comparative value of the strategies being evaluated.

Discussion

The results of this study have the potential to demonstrate the effectiveness and cost-effectiveness of offering PrEP and HCV treatment in healthcare venues frequently attended by PWID. Testing the intervention in two urban centers with high disease burden among PWID, but with different healthcare system dynamics, will increase generalizability of findings.

Trial registration

Clinicaltrials.gov NCT03981445. Trial registry name: Integrated HIV Prevention and HCV Care for PWID (M2HepPrEP). Registration date: June 10, 201.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06085-3.

Phylogenetic prioritization of HIV-1 transmission clusters with viral lineage-level diversification rates

Background and objectives

Public health officials faced with a large number of transmission clusters require a rapid, scalable and unbiased way to prioritize distribution of limited resources to maximize benefits. We hypothesize that transmission cluster prioritization based on phylogenetically derived lineage-level diversification rates will perform as well as or better than commonly used growth-based prioritization measures, without need for historical data or subjective interpretation.

Methodology

9822 HIV pol sequences collected during routine drug resistance genotyping were used alongside simulated sequence data to infer sets of phylogenetic transmission clusters via patristic distance threshold. Prioritized clusters inferred from empirical data were compared to those prioritized by the current public health protocols. Prioritization of simulated clusters was evaluated based on correlation of a given prioritization measure with future cluster growth, as well as the number of direct downstream transmissions from cluster members.

Results

Empirical data suggest diversification rate-based measures perform comparably to growth-based measures in recreating public heath prioritization choices. However, unbiased simulated data reveals phylogenetic diversification rate-based measures perform better in predicting future cluster growth relative to growth-based measures, particularly long-term growth. Diversification rate-based measures also display advantages over growth-based measures in highlighting groups with greater future transmission events compared to random groups of the same size. Furthermore, diversification rate measures were notably more robust to effects of decreased sampling proportion.

Conclusions and implications

Our findings indicate diversification rate-based measures frequently outperform growth-based measures in predicting future cluster growth and offer several additional advantages beneficial to optimizing the public health prioritization process.

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.

Modeling the Impact of Social Determinants of Health on HIV

There is growing evidence for the key role of social determinants of health (SDOH) in understanding morbidity and mortality outcomes globally. Factors such as stigma, racism, poverty or access to health and social services represent complex constructs that affect population health via intricate relationships to individual characteristics, behaviors and disease prevention and treatment outcomes. Modeling the role of SDOH is both critically important and inherently complex. Here we describe different modeling approaches and their use in assessing the impact of SDOH on HIV/AIDS. The discussion is thematically divided into mechanistic models and statistical models, while recognizing the overlap between them. To illustrate mechanistic approaches, we use examples of compartmental models and agent-based models; to illustrate statistical approaches, we use regression and statistical causal models. We describe model structure, data sources required, and the scope of possible inferences, highlighting similarities and differences in formulation, implementation, and interpretation of different modeling approaches. We also indicate further needed research on representing and quantifying the effect of SDOH in the context of models for HIV and other health outcomes in recognition of the critical role of SDOH in achieving the goal of ending the HIV epidemic and improving overall population health.

Can the combination of TasP and PrEP eliminate HIV among MSM in British Columbia, Canada?

INTRODUCTION

In British Columbia (BC), the HIV epidemic continues to disproportionally affect the gay, bisexual and other men who have sex with men (MSM). In this study, we aimed to evaluate how Treatment as Prevention (TasP) and pre-exposure prophylaxis (PrEP), if used in combination, could lead to HIV elimination in BC among MSM.

METHODS

Considering the heterogeneity in HIV transmission risk, we developed a compartmental model stratified by age and risk-taking behaviour for the HIV epidemic among MSM in BC, informed by clinical, behavioural and epidemiological data. Key outcome measures included the World Health Organization (WHO) threshold for disease elimination as a public health concern and the effective reproduction number (R_e). Model interventions focused on the optimization of different TasP and PrEP components. Sensitivity analysis was done to evaluate the impact of sexual mixing patterns, PrEP effectiveness and increasing risk-taking behaviour.

RESULTS

The incidence rate was estimated to be 1.2 (0.9-1.9) per 1000 susceptible MSM under the Status Quo scenario by the end of 2029. Optimizing all aspects of TasP and the simultaneous provision of PrEP to high-risk MSM resulted in an HIV incidence rate as low as 0.4 (0.3-0.6) per 1000 susceptible MSM, and an R_e as low as 0.7 (0.6-0.9), indicating that disease elimination was possible when TasP and PrEP were combined. Provision of PrEP to younger MSM or high-risk and younger MSM resulted in a similar HIV incidence rate, but an R_e with credible intervals that crossed one.

CONCLUSION

Further optimizing all aspects of TasP and prioritizing PrEP to high-risk MSM can achieve the goal of disease elimination in BC. These results should inform public health policy development and intervention programs that address the HIV epidemic in BC and in other similar settings where MSM are disproportionately affected.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Impact of Treatment as Prevention on the HIV Epidemic in British Columbia, Canada

PURPOSE OF REVIEW

This study proposes to describe the impact of a publicly funded Treatment as Prevention (TasP) strategy in British Columbia (BC), Canada, in decreasing the individual and public health impact of the HIV/AIDS Epidemic.

RECENT FINDINGS

In BC, TasP has been associated with a steady decline in HIV-related morbidity and mortality. At the same time, a demographic transition was observed among people living with HIV (PLWH), with the majority of those on antiretroviral treatment (ART) now ≥ 50 years of age, living with at least one comorbidity, and dying from age-associated comorbidities. We also documented a progressive increase in the proportion of viral load suppression as a result of ART expansion. While the pre-ART CD4 T cell count has increased steadily in recent years, there is still a large proportion of PLWH being diagnosed in later stages of HIV infection. New HIV diagnoses have been rapidly declining, however to a lesser extent among men who have sex with men (MSM), and BC is currently experiencing an increase in infectious syphilis cases in this population. These facts reinforce the effectiveness of TasP in decreasing HIV transmission, but at the same time, it highlights the need for further innovation to enhance the control of HIV and syphilis among MSM. This study supports the development of new approaches that address existing gaps in the TasP strategy in BC, and the future health needs of PLWH.

Prioritizing Additional Data Collection to Reduce Decision Uncertainty in the HIV/AIDS Response in 6 US Cities: A Value of Information Analysis

OBJECTIVES

The ambitious goals of the US Ending the HIV Epidemic initiative will require a targeted, context-specific public health response. Model-based economic evaluation provides useful guidance for decision making while characterizing decision uncertainty. We aim to quantify the value of eliminating uncertainty about different parameters in selecting combination implementation strategies to reduce the public health burden of HIV/AIDS in 6 US cities and identify future data collection priorities.

METHODS

We used a dynamic compartmental HIV transmission model developed for 6 US cities to evaluate the cost-effectiveness of a range of combination implementation strategies. Using a metamodeling approach with nonparametric and deep learning methods, we calculated the expected value of perfect information, representing the maximum value of further research to eliminate decision uncertainty, and the expected value of partial perfect information for key groups of parameters that would be collected together in practice.

RESULTS

The population expected value of perfect information ranged from $59 683 (Miami) to $54 108 679 (Los Angeles). The rank ordering of expected value of partial perfect information on key groups of parameters were largely consistent across cities and highest for parameters pertaining to HIV risk behaviors, probability of HIV transmission, health service engagement, HIV-related mortality, health utility weights, and healthcare costs. Los Angeles was an exception, where parameters on retention in pre-exposure prophylaxis ranked highest in contributing to decision uncertainty.

CONCLUSIONS

Funding additional data collection on HIV/AIDS may be warranted in Baltimore, Los Angeles, and New York City. Value of information analysis should be embedded into decision-making processes on funding future research and public health intervention.

Preventing HIV outbreaks among people who inject drugs in the United States: plus ça change, plus ça même chose

: This editorial review covers current trends in the epidemiology of HIV among people who inject drugs (PWID) in the United States, including four recent HIV outbreaks. We discuss gaps in the prevention and treatment cascades for HIV and medications for opioid disorder and propose lessons learned to prevent future HIV outbreaks. Over the last decade, North America has been in the throes of a major opioid epidemic, due in part to over-prescribing of prescription opiates, followed by increasing availability of cheap heroin, synthetic opioids (e.g. fentanyl), and stimulants (e.g. methamphetamine). Historically, HIV infection among PWID in the US had predominantly affected communities who were older, urban and Black. More recently, the majority of these infections are among younger, rural or suburban and Caucasian PWID. All four HIV outbreaks were characterized by a high proportion of women who inject drugs and underlying socioeconomic drivers such as homelessness and poverty. We contend that the US response to the HIV epidemic among PWID has been fractured. A crucial lesson is that when evidence-based responses to HIV prevention are undermined or abandoned because of moral objections, untold humanitarian and financial costs on public health will ensue. Restructuring a path forward requires that evidence-based interventions be integrated and brought to scale while simultaneously addressing underlying structural drivers of HIV and related syndemics. Failing to do so will mean that HIV outbreaks among PWID and the communities they live in will continue to occur in a tragic and relentless cycle.

Behavioural, social and structural-level risk factors for developing AIDS among HIV-positive people who use injection drugs in a Canadian setting, 1996-2017

People who use injection drugs (PWID) experience high rates of HIV acquisition and, as a result of lower rates of optimal access and adherence to combination antiretroviral therapy (ART), experience worse HIV treatment outcomes than other key affected populations. However, the incidence and risk factors for the development of AIDS among HIV-positive PWID have not been completely described. We used data from a community-recruited prospective cohort of HIV-positive PWID in Vancouver, Canada, a setting with universal no-cost ART and a comprehensive clinical monitoring registry. We used multivariable extended Cox models to identify factors associated with time to AIDS. Between 1996 and 2017, 396 participants, including 140 (35.4%) women, were followed for a median of 39.0 months (interquartile range: 16.6-76.2), among whom 165 (41.7%) developed AIDS. In a multivariable model, homelessness (Adjusted Hazard Ratio [AHR] = 1.76 (1.18-2.61)) and injection drug use within the preceding six months (AHR = 1.74 (1.17-2.58)) were independently associated with a higher risk of developing AIDS. Despite widespread scale-up of programmes to improve ART utilization, significant risk factors for the development of AIDS remain among HIV-positive PWID in this setting.

Why Maximizing Quality-Adjusted Life Years, rather than Reducing HIV Incidence, Must Remain Our Objective in Addressing the HIV/AIDS Epidemic

With efficacious behavioral, biomedical, and structural interventions available, combination implementation strategies are being implemented to combat HIV/AIDS across settings internationally. However, priority statements from national and international bodies make it unclear whether the objective should be the reduction in HIV incidence or the maximization of health, most commonly measured with quality-adjusted life years (QALYs). Building off a model-based evaluation of HIV care interventions in British Columbia, Canada, we compare the optimal sets of interventions that would be identified using HIV infections averted, and QALYs as the primary outcome in a cost-effectiveness analysis. We found an explicit focus on averting new infections undervalues the health benefits derived from antiretroviral therapy, resulting in suboptimal and potentially harmful funding recommendations.

The impact of high-dose opioid prescription on mortality rates among people living with HIV: A retrospective cohort study

OBJECTIVES

High-dose opioid use is associated with increased morbidity, mortality, and healthcare utilization. People living with HIV (PLHIV) are frequently prescribed these medications to manage their pain. However, little is known about the relationship between being prescribed high doses of opioids (> 90 MME/d) and mortality risk among this population. The objective of this study was to examine the trends in mortality and the relationship between high-dose opioid analgesic prescribing and mortality among PLHIV.

METHODS

Utilizing the STOP HIV/AIDS cohort--a population-level linked database of treatment of PLHIV in British Columbia--we conducted bivariable and multivariable generalized estimating equation (GEE) models with a Poisson distribution to examine the relationship between high-dose opioid prescription and all-cause mortality rates in the study sample.

RESULTS

Between 1996 and 2015, 9272 PLHIV were included in the study. Age- and sex-adjusted mortality rate (using the 2011 Canadian population as the reference) was 30.99 per 1000 person-years (95% confidence interval [CI]: 28.11-33.88). In a multivariable GEE model with adjustment for various demographic and clinical confounders, there was a positive and independent association between being prescribed high-dose opioids and all-cause mortality rates (adjusted rate ratio [ARR] = 3.01; 95%CI: 2.47-3.66).

DISCUSSION

We found that mortality rates were significantly higher among PLHIV who were prescribed high-dose opioids compared to those who were prescribed lower doses. Our results highlight the risk associated with the prescribing of high-dose opioids to manage HIV-related pain and emphasize the need to explore non-opioid approaches to pain management.

The impact of localized implementation: determining the cost-effectiveness of HIV prevention and care interventions across six United States cities

OBJECTIVE

Effective interventions to reduce the public health burden of HIV/AIDS can vary in their ability to deliver value at different levels of scale and in different epidemiological contexts. Our objective was to determine the cost-effectiveness of HIV treatment and prevention interventions implemented at previously documented scales of delivery in six US cities with diverse HIV microepidemics.

DESIGN

Dynamic HIV transmission model-based cost-effectiveness analysis.

METHODS

We identified and estimated previously documented scale of delivery and costs for 16 evidence-based interventions from the US CDC's Compendium of Evidence-Based Interventions and Best Practices for HIV Prevention. Using a model calibrated for Atlanta, Baltimore, Los Angeles, Miami, New York City and Seattle, we estimated averted HIV infections, quality-adjusted life years (QALY) gained and incremental cost-effectiveness ratios (healthcare perspective; 3% discount rate, 2018$US), for each intervention and city (10-year implementation) compared with the status quo over a 20-year time horizon.

RESULTS

Increased HIV testing was cost-saving or cost-effective across cities. Targeted preexposure prophylaxis for high-risk MSM was cost-saving in Miami and cost-effective in Atlanta ($6123/QALY), Baltimore ($18 333/QALY) and Los Angeles ($86 117/QALY). Interventions designed to improve antiretroviral therapy initiation provided greater value than other treatment engagement interventions. No single intervention was projected to reduce HIV incidence by more than 10.1% in any city.

CONCLUSION

Combination implementation strategies should be tailored to local epidemiological contexts to provide the most value. Complementary strategies addressing factors hindering access to HIV care will be necessary to meet targets for HIV elimination in the United States.

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

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

Incidence of select chronic comorbidities among a population-based cohort of HIV-positive individuals receiving highly active antiretroviral therapy

Objective: To characterize the incidence of select chronic comorbidities in the era of modern (pre-integrase-inhibitor) highly active antiretroviral therapy (HAART) in British Columbia, Canada. Methods: We used data from the Comparative Outcomes And Service Utilization Trends (COAST) study, a population-based cohort study of people living with HIV (PLWH), to determine incidence rates of six key chronic diseases among PLWH receiving HAART in BC from 2000 to 2012. The selected diseases included cardiovascular disease (CVD), diabetes mellitus (DM), hypertension (HTN), asthma/chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD) and chronic liver disease (CLD) defined using ICD-9 and -10 codes. Disease incidence was determined by number of new cases per year. We used Poisson regression to measure trends in incidence rates. Results: The study sample (n = 10,210) was predominantly male (83%), white (72%) and younger than 50 years of age at HAART initiation (88%). Incidence rates of HTN per 1000 person-years (PY) increased significantly between 2000 and 2012, after adjusting for age, sex, baseline-weighted Charlson Comorbidity Index, CD4 cell count and viral load (p < .001); incidence rates of CKD and CLD decreased significantly over time (p < .001). Unadjusted incidence rates of DM increased over time (p < .01), but remained stable in the adjusted model. Incidence rate patterns for CVD and COPD/asthma were stable over the study period. Conclusions: Population-level increases in incidence rates for HTN, and decreases for CLD and CKD, were observed among PLWH on modern (pre-integrase-inhibitor) HAART from 2000 to 2012. Overall, the increasing incidence of several of these chronic comorbidities in our study suggests that further efforts are needed to maximize the potential for healthy aging among PLWH receiving modern (pre-integrase-inhibitor) HAART.

Developing a dynamic HIV transmission model for 6 U.S. cities: An evidence synthesis

BACKGROUND

Dynamic HIV transmission models can provide evidence-based guidance on optimal combination implementation strategies to treat and prevent HIV/AIDS. However, these models can be extremely data intensive, and the availability of good-quality data characterizing regional microepidemics varies substantially within and across countries. We aim to provide a comprehensive and transparent description of an evidence synthesis process and reporting framework employed to populate and calibrate a dynamic, compartmental HIV transmission model for six US cities.

METHODS

We executed a mixed-method evidence synthesis strategy to populate model parameters in six categories: (i) initial HIV-negative and HIV-infected populations; (ii) parameters used to calculate the probability of HIV transmission; (iii) screening, diagnosis, treatment and HIV disease progression; (iv) HIV prevention programs; (v) the costs of medical care; and (vi) health utility weights for each stage of HIV disease progression. We identified parameters that required city-specific data and stratification by gender, risk group and race/ethnicity a priori and sought out databases for primary analysis to augment our evidence synthesis. We ranked the quality of each parameter using context- and domain-specific criteria and verified sources and assumptions with our scientific advisory committee.

FINDINGS

To inform the 1,667 parameters needed to populate our model, we synthesized evidence from 59 peer-reviewed publications and 24 public health and surveillance reports and executed primary analyses using 11 data sets. Of these 1,667 parameters, 1,517 (91%) were city-specific and 150 (9%) were common for all cities. Notably, 1,074 (64%), 201 (12%) and 312 (19%) parameters corresponded to categories (i), (ii) and (iii), respectively. Parameters ranked as best- to moderate-quality evidence comprised 39% of the common parameters and ranged from 56%-60% across cities for the city-specific parameters. We identified variation in parameter values across cities as well as within cities across risk and race/ethnic groups.

CONCLUSIONS

Better integration of modelling in decision making can be achieved by systematically reporting on the evidence synthesis process that is used to populate models, and by explicitly assessing the quality of data entered into the model. The effective communication of this process can help prioritize data collection of the most informative components of local HIV prevention and care services in order to reduce decision uncertainty and strengthen model conclusions.

Undiagnosed HIV infections among gay and bisexual men increasingly contribute to new infections in Australia

Introduction

We determined the contribution of undiagnosed HIV to new infections among gay and bisexual men (GBM) over a 12‐year period in Australia where there has been increasing focus on improving testing and HIV treatment coverage.

Methods

We generated annual estimates for each step of the HIV cascade and the number of new HIV infections for GBM in Australia over 2004 to 2015 using relevant national data. Using Bayesian melding we then fitted a quantitative model to the cascade and incidence estimates to infer relative transmission coefficients associated with being undiagnosed, diagnosed and not on ART, on ART with unsuppressed virus, or on ART with suppressed virus.

Results

Between 2004 and 2015, we estimated the percentage of GBM with HIV in Australia who were unaware of their status to have decreased from 14.5% to 7.5%. During the same period, there was a substantial increase in the number and proportion of GBM living with HIV on treatment and with suppressed virus, with the number of virally suppressed GBM increasing from around 3900 (30.2% of all GBM living with HIV) in 2004 to around 14,000 (73.7% of all GBM living with HIV) in 2015. Despite the increase in viral suppression, the annual number of new infections rose from around 660 to around 760 over this period. Our results have a wide range due to the uncertainty in the cascade estimates and transmission coefficients. Nevertheless, undiagnosed GBM increasingly appear to contribute to new infections. The proportion of new infections attributable to undiagnosed GBM almost doubled from 33% in 2004 to 59% in 2015. Only a small proportion (<7%) originated from GBM with suppressed virus.

Discussion

Our study suggests that an increase in HIV treatment coverage in Australia has reduced the overall risk of HIV transmission from people living with HIV. However, the proportion of infections and the rate of transmission from undiagnosed GBM has increased substantially. These findings highlight the importance of HIV testing and intensified prevention for Australian GBM at high risk of HIV.

Realizing Women Living with HIV's Reproductive Rights in the Era of ART: The Negative Impact of Non-consensual HIV Disclosure on Pregnancy Decisions Amongst Women Living with HIV in a Canadian Setting

To better understand the structural drivers of women living with HIV's (WLWH's) reproductive rights and choices, this study examined the structural correlates, including non-consensual HIV disclosure, on WLWH's pregnancy decisions and describes access to preconception care. Analyses drew on data (2014-present) from SHAWNA, a longitudinal community-based cohort with WLWH across Metro-Vancouver, Canada. Multivariable logistic regression was used to model the effect of non-consensual HIV disclosure on WLWH's pregnancy decisions. Of the 218 WLWH included in our analysis, 24.8% had ever felt discouraged from becoming pregnant and 11.5% reported accessing preconception counseling. In multivariable analyses, non-consensual HIV disclosure was positively associated with feeling discouraged from wanting to become pregnant (AOR 3.76; 95% CI 1.82-7.80). Non-consensual HIV disclosure adversely affects WLWH's pregnancy decisions. Supporting the reproductive rights of WLWH will require further training among general practitioners on the reproductive health of WLWH and improved access to women-centred, trauma-informed care, including non-judgmental preconception counseling.

Health Care Provider Utilization and Cost of an mHealth Intervention in Vulnerable People Living With HIV in Vancouver, Canada: Prospective Study

Background

Improving adherence to combined antiretroviral therapy (cART) can be challenging, especially among vulnerable populations living with HIV. Even where cART is available free of charge, social determinants of health act as barriers to optimal adherence rates. Patient-centered approaches exploiting mobile phone communications (mHealth) have been shown to improve adherence to cART and promote achievement of suppressed HIV plasma viral loads. However, data are scarce on the health care provider (HCP) time commitments and health care costs associated with such interventions. This knowledge is needed to inform policy and programmatic implementation.

Objective

The purpose of this study was to approximate the resources required and to provide an estimate of the costs associated with running an mHealth intervention program to improve medication adherence in people living with HIV (PLWH).

Methods

This prospective study of HCP utilization and costs was embedded within a repeated measures effectiveness study of the WelTel short-message service (SMS) mHealth program. The study included 85 vulnerable, nonadherent PLWH in Vancouver, Canada, and resulted in improved medication adherence and HIV plasma viral load among participants. Study participants were provided mobile phones with unlimited texting (where required) and received weekly bidirectional text messages to inquire on their status for one year. A clinic nurse triaged and managed participants' responses, immediately logging all patient interactions by topic, HCP involvement, and time dedicated to addressing issues raised by participants. Interaction costs were determined in Canadian dollars based on HCP type, median salary within our health authority, and their time utilized as part of the intervention.

Results

Participant-identified problems within text responses included health-related, social, and logistical issues. Taken together, management of problems required a median of 43 minutes (interquartile range, IQR 17-99) of HCP time per participant per year, for a median yearly cost of Can $36.72 (IQR 15.50-81.60) per participant who responded with at least one problem. The clinic nurse who monitored the texts solved or managed 65% of these issues, and the remaining were referred to a variety of other HCPs. The total intervention costs, including mobile phones, plans, and staffing were a median Can $347.74/highly vulnerable participant per year for all participants or Can $383.18/highly vulnerable participant per year for those who responded with at least one problem.

Conclusions

Bidirectional mHealth programs improve HIV care and treatment outcomes for PLWH. Knowledge about the HCP cost associated, here less than Can $50/year, provides stakeholders and decision makers with information relevant to determining the feasibility and sustainability of mHealth programs in a real-world setting.

Trial Registration

ClinicalTrials.gov NCT02603536; https://clinicaltrials.gov/ct2/show/NCT02603536 (Archived by WebCite at http://www.webcitation.org/70IYqKUjV).

Syringe sharing among people who inject drugs in London, Canada

OBJECTIVES

London, Ontario, is facing an outbreak of HIV among people who inject drugs (PWID), as well as persistently high levels of hepatitis C virus (HCV). Syringe sharing is the primary driver of HIV and HCV transmission risks among PWID, however, little is known about factors contributing to syringe sharing in this setting. Therefore, we sought to characterize syringe sharing and its correlates among London PWID.

METHODS

Between March and April, 2016, PWID participated in a survey administered by peer research associates as part of the Ontario Integrated Supervised Injection Services Feasibility Study. Bivariable and multivariable logistic regression models examined associations with syringe sharing (borrowing or lending previously used syringes) over the previous 6 months. A sub-analysis described patterns of borrowing and lending by self-reported HIV and HCV statuses.

RESULTS

Of 198 PWID, 44 (22%) reported syringe sharing in the past 6 months. In the multivariable analysis, selling drugs (adjusted odds ratio; AOR = 1.92, 95% CI = 1.20-3.08), daily crystal methamphetamine injection (AOR = 1.66, 95% CI = 1.07-2.59), and identifying as HIV-positive (AOR = 3.11, 95% CI = 1.61-6.01) were independently associated with increased syringe sharing. While not independently associated with syringe sharing, problems accessing syringes were common (13-50%). Self-reported HIV-positive respondents were more likely to report syringe borrowing (p < 0.001), but not lending (p = 0.26).

CONCLUSION

We observed a high rate of syringe sharing among London PWID, with sharing being associated with high-intensity injection of crystal methamphetamine, as well as with involvement in drug sales. Considering the current HIV outbreak in London, multi-level prevention efforts are urgently needed.

The Cost-Effectiveness of Human Immunodeficiency Virus Testing and Treatment Engagement Initiatives in British Columbia, Canada: 2011-2013

Background

Recognition of the secondary preventive benefits of antiretroviral therapy (ART) has mobilized global efforts to "seek, test, treat, and retain" people living with human immunodeficiency virus [HIV]/AIDS (PLHIV) in HIV care. We aimed to determine the cost-effectiveness of a set of HIV testing and treatment engagement interventions initiated in British Columbia, Canada, in 2011-2013.

Methods

Using a previously validated dynamic HIV transmission model, linked individual-level health administrative data for PLHIV, and aggregate-level HIV testing data, we estimated the cost-effectiveness of primary care testing (hospital, emergency department [ED], outpatient), ART initiation, and ART retention initiatives vs a counterfactual scenario that approximated the status quo. HIV incidence, mortality, costs (in 2015$CDN), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios were estimated. Analyses were executed over 5- to 25-year time horizons from a government-payer perspective.

Results

ED testing was the best value at $30216 per QALY gained and had the greatest impact on incidence and mortality among PLHIV, while ART initiation provided the greatest QALY gains. The ART retention initiative was not cost-effective. Delivered in combination at the observed scale and sustained throughout the study period, we estimated a 12.8% reduction in cumulative HIV incidence and a 4.7% reduction in deaths among PLHIV at $55258 per QALY gained. Results were most sensitive to uncertainty in the number of undiagnosed PLHIV.

Conclusions

HIV testing and ART initiation interventions were cost-effective, while the ART retention intervention was not. Developing strategies to reengage PLHIV lost to care is a priority moving forward.

Setting the stage for expanding HIV pre-exposure prophylaxis use in Canada

Human immunodeficiency virus (HIV) infection continues to disproportionately affect vulnerable populations in Canada; particularly men who have sex with men (MSM). Novel HIV prevention strategies have recently expanded from the use of non-occupational post-exposure prophylaxis (nPEP) after high risk exposures to the use of pre-exposure prophylaxis (PrEP) in which individuals reduce risk of HIV infection through use of combination antiretrovirals taken prior to risk exposure. With approval of tenofovir/emtricitabine (TDF/FTC) for use as PrEP only in early 2016, and with limited public funding to date, uptake in Canada is in its preliminary stages. These biomedical prevention strategies have proven efficacy for MSM, and they may have potential for other at-risk populations. With generic formulations of TDF/FTC now available in Canada, there is an opportunity for widespread implementation. Expanding knowledge of health care providers across Canada on how best to assess, refer for or prescribe and monitor PrEP will contribute to the current efforts to reach the global goal of eliminating new HIV infections.

A historical review of HIV prevention and care initiatives in British Columbia, Canada: 1996-2015

INTRODUCTION

British Columbia has made significant progress in the treatment and prevention of HIV since 1996, when Highly Active Antiretroviral Therapy (HAART) became available. However, we currently lack a historical summary of HIV prevention and care interventions implemented in the province since the introduction of HAART and how they have shaped the HIV epidemic. Guided by a socio-ecological framework, we present a historical review of biomedical and health services, community and structural interventions implemented in British Columbia from 1996-2015 to prevent HIV transmission or otherwise enhance the cascade of HIV care.

METHODS

We constructed a historical timeline of HIV interventions implemented in BC between 1996 and 2015 by reviewing publicly available reports, guidelines and other documents from provincial health agencies, community organizations and AIDS service organizations, and by conducting searches of peer-reviewed literature through PubMed and Ovid MEDLINE. We collected further programmatic information by administering a data collection form to representatives from BC's regional health authorities and an umbrella agency representing 45 AIDS Service organizations. Using linked population-level health administrative data, we identified key phases of the HIV epidemic in British Columbia, as characterized by distinct changes in HIV incidence, HAART uptake and the provincial HIV response.

RESULTS AND DISCUSSION

In total, we identified 175 HIV prevention and care interventions implemented in BC from 1996 to 2015. We identify and describe four phases in BC's response to HIV/AIDS: the early HAART phase (1996-1999); the harm reduction and health service scale-up phase (2000-2005); the early Treatment as Prevention phase (2006-2009); and the STOP HIV/AIDS phase (2010-present). In doing so, we provide an overview of British Columbia's universal and centralized HIV treatment system and detail the role of community-based and provincial stakeholders in advancing innovative prevention and harm reduction approaches, as well as "seek, test, treat and retain" strategies.

CONCLUSIONS

The review provides valuable insight into British Columbia's HIV response, highlights emerging priorities, and may inform future efforts to evaluate the causal impact of interventions.

Initiating HCV treatment with direct acting agents in opioid agonist treatment: When to start for people co-infected with HIV?

BACKGROUND

Direct acting antivirals (DAA) raise the possibility of eliminating Hepatitis C virus (HCV) among people who inject drugs (PWID). However, concerns regarding treatment retention and reinfection challenge implementation efforts. Opioid agonist treatment (OAT) provides an opportunity to engage HCV-positive PWID into DAA-based treatment. Our objective was to identify when OAT adherence sufficiently improved to inform DAA initiation in OAT settings, assuming continuous OAT retention for at least twelve weeks is necessary to complete the DAA treatment course.

METHODS

This was a retrospective cohort study of HCV/HIV co-infected PWID from a population-level linked administrative database of people diagnosed and living with HIV in British Columbia, Canada between 01/1996 and 12/2013. We used monthly follow-up data after initial OAT entry and considered the effects of demographics, disease severity, and HIV and OAT treatment characteristics over time on the probability of subsequent OAT retention of ≥12 weeks, and ≥8 weeks for sensitivity analysis. We fit a generalized linear mixed model to the overall study population, and on stratified samples of those continuously engaged on combination antiretroviral therapy (≥95% ART adherence). A set of monthly indicator variables (months 1, …, 7, >7) were included to fulfil the study objective.

RESULTS

Our study included 1427 HCV/HIV co-infected PWID (39.0% female, 68.8% OAT-naïve). The odds of subsequent twelve-week retention in OAT were statistically significantly greater in month 3 versus month 1 (adjusted odds ratio: 1.18; 95% confidence interval: 1.02, 1.37); and the odds of subsequent 8-week retention in OAT were statistically significantly greater in month 2 versus month 1 (1.15, 95% CI: 1.02, 1.31). Among continuously ART-adherent individuals, the odds of subsequent twelve-week retention were not statistically significantly greater than in month 1 (month 2: 1.12 (0.82, 1.51); month 3: 1.08 (0.79, 1.47); month 4: 1.24 (0.91, 1.71)).

CONCLUSION

We provide evidence that among HCV/HIV co-infected PWID, those retained in OAT for three or more months had higher odds of completing an additional twelve weeks of OAT, compared to no difference in those already receiving ART. These data may have implications for adherence to DAA therapy and further studies are needed to understand the optimal timing of DAA therapy in PWID receiving and not receiving OAT.