Publications
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Cepeda JA, Beletsky L, Abramovitz D, et al., 2024, Cost-effectiveness of a police education program on HIV and overdose among people who inject drugs in Tijuana, Mexico, The Lancet Regional Health - Americas, Vol: 30
Background: Incarceration is associated with drug-related harms among people who inject drugs (PWID). We trained >1800 police officers in Tijuana, Mexico on occupational safety and HIV/HCV, harm reduction, and decriminalization reforms (Proyecto Escudo). We evaluated its effect on incarceration, population impact and cost-effectiveness on HIV and fatal overdose among PWID. Methods: We assessed self-reported recent incarceration in a longitudinal cohort of PWID before and after Escudo. Segmented regression was used to compare linear trends in log risk of incarceration among PWID pre-Escudo (2012–2015) and post-Escudo (2016–2018). We estimated population impact using a dynamic model of HIV transmission and fatal overdose among PWID, with incarceration associated with syringe sharing and fatal overdose. The model was calibrated to HIV and incarceration patterns in Tijuana. We compared a scenario with Escudo (observed incarceration declines for 2 years post-Escudo among PWID from the segmented regression) compared to a counterfactual of no Escudo (continuation of stable pre-Escudo trends), assessing cost-effectiveness from a societal perspective. Using a 2-year intervention effect and 50-year time horizon, we determined the incremental cost-effectiveness ratio (ICER, in 2022 USD per disability-adjusted life years [DALYs] averted). Findings: Compared to stable incarceration pre-Escudo, for every three-month interval in the post-Escudo period, recent incarceration among PWID declined by 21% (adjusted relative risk = 0.79, 95% CI: 0.68–0.91). Based on these declines, we estimated 1.7% [95% interval: 0.7%–3.5%] of new HIV cases and 12.2% [4.5%–26.6%] of fatal overdoses among PWID were averted in the 2 years post-Escudo, compared to a counterfactual without Escudo. Escudo was cost-effective (ICER USD 3746/DALY averted compared to a willingness-to-pay threshold of $4842–$13,557). Interpretation: Escudo is a cost-effective structural inte
Friedman J, Godvin M, Molina C, et al., 2023, Fentanyl, heroin, and methamphetamine-based counterfeit pills sold at tourist-oriented pharmacies in Mexico: An ethnographic and drug checking study, DRUG AND ALCOHOL DEPENDENCE, Vol: 249, ISSN: 0376-8716
Bailey K, Abramovitz D, Artamonova I, et al., 2023, Drug checking in the fentanyl era: Utilization and interest among people who inject drugs in San Diego, California., Int J Drug Policy, Vol: 118
BACKGROUND: In North America, overdose rates have steeply risen over the past five years, largely due to the ubiquity of illicitly manufactured fentanyls in the drug supply. Drug checking services (DCS) represent a promising harm reduction strategy and characterizing experiences of use and interest among people who inject drugs (PWID) is a priority. METHODS: Between February-October 2022, PWID participating in a cohort study in San Diego, CA and Tijuana, Mexico completed structured surveys including questions about DCS, socio-demographics and substance use behaviors. We used Poisson regression to assess factors associated with lifetime DCS use and characterized experiences with DCS and interest in free access to DCS. RESULTS: Of 426 PWID, 72% were male, 59% Latinx, 79% were experiencing homelessness and 56% ever experienced a nonfatal overdose. One third had heard of DCS, of whom 57% had ever used them. Among the latter, most (98%) reported using fentanyl test strips (FTS) the last time they used DCS; 66% did so less than once per month. In the last six months, respondents used FTS to check methamphetamine (48%), heroin (30%) or fentanyl (29%). Relative to White/non-Latinx PWID, those who were non-White/Latinx were significantly less likely to have used DCS [adjusted risk ratio (aRR): 0.22; 95% CI: 0.10, 0.47), as were PWID experiencing homelessness (aRR:0.45; 95% CI: 0.28, 0.72). However, a significant interaction indicated that non-White/Latinx syringe service program (SSP) clients were more likely to have used DCS than non-SSP clients (aRR: 2.79; CI: 1.09, 7.2). Among all PWID, 44% expressed interest in free access to FTS, while 84% (of 196 PWID) expressed interest in advanced spectrometry DCS to identify and quantify multiple substances. CONCLUSIONS: Our findings highlight low rates of DCS awareness and utilization, inequities by race/ethnicity and housing situation, high interest in advanced spectrometry DCS versus FTS, and the potential role of SSPs in improvi
Saldana CRD, Abramovitz D, Beletsky L, et al., 2023, Estimating the impact of a police education program on hepatitis C virus transmission and disease burden among people who inject drugs in Tijuana, Mexico: A dynamic modeling analysis, ADDICTION, ISSN: 0965-2140
Patton T, Abramovitz D, Johnson D, et al., 2022, Characterizing Help-Seeking Searches for Substance Use Treatment From Google Trends and Assessing Their Use for Infoveillance: Longitudinal Descriptive and Validation Statistical Analysis, JOURNAL OF MEDICAL INTERNET RESEARCH, Vol: 24, ISSN: 1438-8871
Bradley H, Austin C, Allen ST, et al., 2022, A stakeholder-driven framework for measuring potential change in the health risks of people who inject drugs (PWID) during the COVID-19 pandemic, INTERNATIONAL JOURNAL OF DRUG POLICY, Vol: 110, ISSN: 0955-3959
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- Citations: 1
Saldana CDR, Beletsky L, Borquez A, et al., 2022, Modelling the contribution of incarceration and public health oriented drug law reform to HCV transmission and elimination among PWID in Tijuana, Mexico, INTERNATIONAL JOURNAL OF DRUG POLICY, Vol: 110, ISSN: 0955-3959
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- Citations: 1
Borquez A, 2022, Commentary on Savinkina <i>et al</i>.: Reforming drug 'detox' centers-what will it entail and where do we begin?, ADDICTION, Vol: 117, Pages: 2462-2463, ISSN: 0965-2140
Patton T, Abramovitz D, Johnson D, et al., 2022, Help-Seeking for Substance Use Treatment on Internet Search Engines (Preprint)
<sec> <title>BACKGROUND</title> <p>There is no recognized “gold standard” method for estimating the number of individuals with substance use disorders (SUD) seeking help within a given geographical area. This presents a challenge to policymakers in the effective deployment of resources for the treatment of SUD. Internet search queries related to help-seeking for SUDs may represent a low-cost, real-time, and data-driven strategy to address this shortfall in information.</p> </sec> <sec> <title>OBJECTIVE</title> <p>This paper assesses the feasibility of using search query data related to help-seeking for SUDs as an indicator of unmet treatment need, demand for treatment, and a predictor of the health harms related to unmet treatment need.</p> </sec> <sec> <title>METHODS</title> <p>We used negative binomial regression models to examine temporal trends in the annual SUD help-seeking internet search queries by U.S. state for cocaine, methamphetamine, opioids, cannabis, and alcohol from 2010 to 2020. To validate the value of these data for surveillance purposes, we then used negative binomial regression models to investigate the relationship between SUD help-seeking searches and state-level outcomes across the continuum of care (including lack of care). We started by looking at associations with self-reported treatment need using data from the National Survey on Drug Use and Health, a national survey of the U.S. general population. Next, we explored associations with treatment admission rates from the Treatment Episode Data Set, a national data system on SUD treatment facilities. Finally, we studied associations with state-level rates of people experie
Vo AT, Patton T, Peacock A, et al., 2022, Illicit Substance Use and the COVID-19 Pandemic in the United States: A Scoping Review and Characterization of Research Evidence in Unprecedented Times, INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, Vol: 19
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- Citations: 5
Chaillon A, Bharat C, Stone J, et al., 2022, Modeling the population-level impact of opioid agonist treatment on mortality among people accessing treatment between 2001 and 2020 in New South Wales, Australia, ADDICTION, Vol: 117, Pages: 1338-1352, ISSN: 0965-2140
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- Citations: 5
Patton T, Revill P, Sculpher M, et al., 2022, Using Economic Evaluation to Inform Responses to the Opioid Epidemic in the United States: Challenges and Suggestions for Future Research, SUBSTANCE USE & MISUSE, Vol: 57, Pages: 815-821, ISSN: 1082-6084
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- Citations: 4
Marks C, Abramovitz D, Donnelly C, et al., 2021, Identifying counties at risk of high overdose mortality burden throughout the emerging fentanyl epidemic in the united states: a predictive statistical modeling study, The Lancet Public Health, Vol: 6, Pages: e720-e728, ISSN: 2468-2667
Background. The emergence of fentanyl around 2013 represented a new, deadly stage in the US opioid epidemic. We developed a statistical regression approach to identify counties at the highest risk of high overdose mortality in the next year by predicting annual county-level overdose death rates across the contiguous US and validated it against observed overdose mortality data from 2013 to 2018.Methods. We fit mixed effects negative binomial regression models to predict next year’s county-level overdose death rates for the years 2013 to 2018. We used publicly available county-level data related to healthcare access, drug markets, socio-demographics, and the geographic spread of opioid overdose as model predictors. The crude number of county-level overdose deaths was extracted from restricted Centers for Disease Control and Prevention mortality records. To predict county-level overdose rates for the year 201X: 1) a model was trained on county-level predictor data for the years 2010-201(X-2) paired with county-level overdose deaths for the year 2011-201(X-1); 2) county-level predictor data for the year 201(X-1) was then fed into the model to predict the 201(X) county-level crude number of overdose deaths; and 3) the latter was converted to a population-adjusted rate. For comparison, we generated a benchmark set of predictions by applying the observed slope of change in overdose death rates in the previous year to 201(X-1) rates. To assess the predictive performance of the model, we compared predicted values (of both the model and benchmark) to observed values by 1) calculating the mean average error, root mean squared error, and Spearman’s correlation coefficient and 2) assessing the proportion of counties in the top decile (10%) of overdose death rates that were correctly predicted as such. Finally, in a post-hoc analysis, we sought to identify variables with greatest predictive utility.Findings. Across the entire US and through time, our modeling approach
Marquez LK, Cepeda JA, Borquez A, et al., 2021, Is hepatitis C virus (HCV) elimination achievable among people who inject drugs in Tijuana, Mexico? A modeling analysis, INTERNATIONAL JOURNAL OF DRUG POLICY, Vol: 88, ISSN: 0955-3959
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- Citations: 6
Cepeda JA, Borquez A, Magana C, et al., 2020, Modelling integrated antiretroviral treatment and harm reduction services on HIV and overdose among people who inject drugs in Tijuana, Mexico, JOURNAL OF THE INTERNATIONAL AIDS SOCIETY, Vol: 23
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- Citations: 9
Borquez A, Rich K, Farrell M, et al., 2020, Integrating HIV pre-exposure prophylaxis and harm reduction among men who have sex with men and transgender women to address intersecting harms associated with stimulant use: a modelling study, JOURNAL OF THE INTERNATIONAL AIDS SOCIETY, Vol: 23
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- Citations: 9
Farrell M, Martin NK, Stockings E, et al., 2019, Responding to global stimulant use: challenges and opportunities, LANCET, Vol: 394, Pages: 1652-1667, ISSN: 0140-6736
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- Citations: 135
Marks C, Borquez A, Jain S, et al., 2019, Opioid agonist treatment scale-up and the initiation of injection drug use: A dynamic modeling analysis, PLOS MEDICINE, Vol: 16, ISSN: 1549-1277
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- Citations: 15
Borquez A, Guanira JV, Revill P, et al., 2019, The impact and cost-effectiveness of combined HIV prevention scenarios among transgender women sex-workers in Lima, Peru: A mathematical modelling study, Lancet Public Health, Vol: 4, Pages: e127-e136, ISSN: 2468-2667
BackgroundHIV incidence remains high among transgender women in Lima, Peru, most of whom report sex work. On the basis of a stakeholder analysis and health system capacity assessment, we designed a mathematical model to guide HIV programmatic planning among transgender women sex workers (TWSW) in Lima.MethodsUsing a deterministic compartmental model, we modelled HIV transmission among TWSW, their stable partners, and their clients to estimate the impact and cost-effectiveness of combinations of interventions compared with the standard of care on reducing HIV incidence over a 10-year period. We simulated HIV transmission accounting for differences in sexual positioning in anal intercourse and condom use by partner type and fitted the model to HIV surveillance data using Latin hypercube sampling. The interventions we considered were 15% relative increase in condom use with clients and 10% relative increase with stable partners; increase in antiretroviral treatment (ART) coverage at CD4 count lower than 500 cells per mm3 and greater than or equal to 500 cells per mm3; and 15% pre-exposure prophylaxis (PrEP) coverage using generic and branded formulations. We considered a basic scenario accounting for current limitations in the Peruvian HIV services and an enhanced scenario assuming achievement of the UNAIDS 90-90-90 targets and general improvements in HIV services. The 50 best fits according to log-likelihood were used to give the minimum and maximum values of intervention effect for each combination. We used disability-adjusted life-years (DALYs) to measure the negative health outcomes associated with HIV infection that could be averted through the interventions investigated and calculated incremental cost-effectiveness ratios to compare their cost-effectiveness.FindingsUnder the basic scenario, combining the four interventions of increasing condom use with clients and stable partners, extending ART to people with CD4 count greater than or equal to 500 cells per mm3
Borquez A, Beletsky L, Nosyk B, et al., 2018, The effect of public health-oriented drug law reform on HIV incidence in people who inject drugs in Tijuana, Mexico: an epidemic modelling study, Lancet Public Health, Vol: 3, Pages: e429-e437, ISSN: 2468-2667
BackgroundAs countries embark on public health-oriented drug law reform, health impact evaluations are needed. In 2012, Mexico mandated the narcomenudeo reform, which depenalised the possession of small amounts of drugs and instituted drug treatment instead of incarceration. We investigated the past and future effect of this drug law reform on HIV incidence in people who inject drugs in Tijuana, Mexico.MethodsIn this epidemic modelling study, we used data from the El Cuete IV cohort study to develop a deterministic model of injecting and sexual HIV transmission in people who inject drugs in Tijuana between 2012 and 2030. The population was stratified by sex, incarceration status, syringe confiscation by the police, HIV stage, and exposure to drug treatment or rehabilitation (either opioid agonist treatment or compulsory drug abstinence programmes). We modelled the effect of these exposures on HIV risk in people who inject drugs, estimating the effect of observed and potential future reform enforcement levels.FindingsIn 2011, prior to the narcomenudeo reform, 547 (75%) of 733 people who inject drugs in the El Cuete cohort reported having ever been incarcerated, on average five times since starting injecting. Modelling estimated the limited reform implementation averted 2% (95% CI 0·2–3·0) of new HIV infections in people who inject drugs between 2012 and 2017. If implementation reduced incarceration in people who inject drugs by 80% from 2018 onward, 9% (95% CI 4–16) of new HIV infections between 2018 and 2030 could be averted, with 21% (10–33) averted if people who inject drugs were referred to opioid agonist treatment instead of being incarcerated. Referral to compulsory drug abstinence programmes instead of prison could have a lower or potentially negative impact with −2% (95% CI −23 to 9) infections averted.InterpretationMexican drug law reform has had a negligible effect on the HIV epidemic among people who inject drugs
Chow JY, Konda KA, Borquez A, et al., 2016, Peru's HIV care continuum among men who have sex with men and transgender women: opportunities to optimize treatment and prevention, INTERNATIONAL JOURNAL OF STD & AIDS, Vol: 27, Pages: 1039-1048, ISSN: 0956-4624
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- Citations: 36
Bórquez A, Cori A, Pufall EL, et al., 2016, The Incidence Patterns Model to Estimate the Distribution of New HIV Infections in Sub-Saharan Africa: Development and Validation of a Mathematical Model., PLOS Medicine, Vol: 13, ISSN: 1549-1277
BACKGROUND: Programmatic planning in HIV requires estimates of the distribution of new HIV infections according to identifiable characteristics of individuals. In sub-Saharan Africa, robust routine data sources and historical epidemiological observations are available to inform and validate such estimates. METHODS AND FINDINGS: We developed a predictive model, the Incidence Patterns Model (IPM), representing populations according to factors that have been demonstrated to be strongly associated with HIV acquisition risk: gender, marital/sexual activity status, geographic location, "key populations" based on risk behaviours (sex work, injecting drug use, and male-to-male sex), HIV and ART status within married or cohabiting unions, and circumcision status. The IPM estimates the distribution of new infections acquired by group based on these factors within a Bayesian framework accounting for regional prior information on demographic and epidemiological characteristics from trials or observational studies. We validated and trained the model against direct observations of HIV incidence by group in seven rounds of cohort data from four studies ("sites") conducted in Manicaland, Zimbabwe; Rakai, Uganda; Karonga, Malawi; and Kisesa, Tanzania. The IPM performed well, with the projections' credible intervals for the proportion of new infections per group overlapping the data's confidence intervals for all groups in all rounds of data. In terms of geographical distribution, the projections' credible intervals overlapped the confidence intervals for four out of seven rounds, which were used as proxies for administrative divisions in a country. We assessed model performance after internal training (within one site) and external training (between sites) by comparing mean posterior log-likelihoods and used the best model to estimate the distribution of HIV incidence in six countries (Gabon, Kenya, Malawi, Rwanda, Swaziland, and Zambia) in the region. We subsequ
Cáceres CF, Borquez A, Klausner JD, et al., 2016, Implementation of pre-exposure prophylaxis for human immunodeficiency virus infection: progress and emerging issues in research and policy., J Int AIDS Soc, Vol: 19
BACKGROUND: In this article, we present recent evidence from studies focused on the implementation, effectiveness and cost-effectiveness of pre-exposure prophylaxis (PrEP) for HIV infection; discuss PrEP scale-up to date, including the observed levels of access and policy development; and elaborate on key emerging policy and research issues to consider for further scale-up, with a special focus on lower-middle income countries. DISCUSSION: The 2015 WHO Early Release Guidelines for HIV Treatment and Prevention reflect both scientific evidence and new policy perspectives. Those guidelines present a timely challenge to health systems for the scaling up of not only treatment for every person living with HIV infection but also the offer of PrEP to those at substantial risk. Delivery and uptake of both universal antiretroviral therapy (ART) and PrEP will require nation-wide commitment and could reinvigorate health systems to develop more comprehensive "combination prevention" programmes and support wider testing linked to both treatments and other prevention options for populations at highest risk who are currently not accessing services. Various gaps in current health systems will need to be addressed to achieve strategic scale-up of PrEP, including developing prioritization strategies, strengthening drug regulations, determining cost and funding sources, training health providers, supporting user adherence and creating demand. CONCLUSIONS: The initial steps in the scale-up of PrEP globally suggest feasibility, acceptability and likely impact. However, to prevent setbacks in less well-resourced settings, countries will need to anticipate and address challenges such as operational and health systems barriers, drug cost and regulatory policies, health providers' openness to prescribing PrEP to populations at substantial risk, demand and legal and human rights issues. Emerging problems will require creative solutions and will continue to illustrate the complexity
Borquez A, Cori A, Pufall E, et al., 2015, ESTIMATING THE DISTRIBUTION OF NEW HIV INFECTIONS BY KEY DETERMINANTS IN GENERALISED EPIDEMICS OF SUB-SAHARAN AFRICA USING A VALIDATED MATHEMATICAL MODEL, Publisher: BMJ PUBLISHING GROUP, Pages: A215-A216, ISSN: 1368-4973
Borquez A, Silva-Santisteban A, Guanira J, et al., 2015, IMPACT AND COST-EFFECTIVENESS OF HIV PREVENTION INTERVENTIONS AMONG TRANSGENDER WOMEN SEX-WORKERS IN LIMA, PERU USING MATHEMATICAL MODELLING INFORMED BY STAKEHOLDER ANALYSIS AND HEALTH SYSTEM CAPACITY EVALUATION, Publisher: BMJ PUBLISHING GROUP, Pages: A52-A52, ISSN: 1368-4973
Poteat T, Wirtz AL, Radix A, et al., 2015, HIV risk and preventive interventions in transgender women sex workers, LANCET, Vol: 385, Pages: 274-286, ISSN: 0140-6736
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- Citations: 257
Rai T, Lambert HS, Borquez AB, et al., 2014, Circular Labor Migration and HIV in India: Exploring Heterogeneity in Bridge Populations Connecting Areas of High and Low HIV Infection Prevalence, Journal of Infectious Diseases, Vol: 210, Pages: S556-S561, ISSN: 1537-6613
BACKGROUND:The emerging human immunodeficiency virus (HIV) epidemics in rural areas of India are hypothesized to be linked to circular migrants who are introducing HIV from destination areas were the prevalence of HIV infection is higher. We explore the heterogeneity in potential roles of circular migrants in driving an HIV epidemic in a rural area in north India and examine the characteristics of the "sustaining bridge population", which comprises individuals at risk of HIV acquisition at destination and of HIV transmission into networks at origin capable of sustaining an epidemic.METHODS:Results of a behavioral survey of 639 male migrants from Azamgarh district, India, were analyzed using χ(2) tests and logistic regression.RESULTS:We estimated the size of various subgroups defined by specific sexual behaviors across different locations and over time. Only 20% fit our definition of a sustaining bridge population, with the majority making no apparent contribution to geographical connectedness between high- and low-prevalence areas. However, we found evidence of sexual contacts at origin that could potentially sustain an epidemic once HIV is introduced. Variables associated with sustaining bridge population membership were self-perceived HIV risk, current migrant status, and age.CONCLUSIONS:Circular migrants represent a heterogeneous population in terms of their role as a bridge group. Self-perception of heightened risk could be exploited in designing prevention programs.
Keebler D, Revill P, Braithwaite S, et al., 2014, Cost-effectiveness of different strategies to monitor adults on antiretroviral treatment: a combined analysis of three mathematical models, LANCET GLOBAL HEALTH, Vol: 2, Pages: E35-E43, ISSN: 2214-109X
Hallett TB, Menzies NA, Revill P, et al., 2014, Using modeling to inform international guidelines for antiretroviral treatment, AIDS, Vol: 28, Pages: S1-S4, ISSN: 0269-9370
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- Citations: 10
Gomez GB, Borquez A, Case KK, et al., 2013, The Cost and Impact of Scaling Up Pre-exposure Prophylaxis for HIV Prevention: A Systematic Review of Cost-Effectiveness Modelling Studies, PLoS Med, Vol: 10
<p>Gabriela Gomez and colleagues systematically review cost-effectiveness modeling studies of pre-exposure prophylaxis (PrEP) for preventing HIV transmission and identify the main considerations to address when considering the introduction of PrEP to HIV prevention programs.</p>
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