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      Effectiveness and Cost Effectiveness of Expanding Harm Reduction and Antiretroviral Therapy in a Mixed HIV Epidemic: A Modeling Analysis for Ukraine

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          Abstract

          A cost-effectiveness study by Sabina Alistar and colleagues evaluates the effectiveness and cost effectiveness of different levels of investment in methadone, ART, or both, in the mixed HIV epidemic in Ukraine.

          Abstract

          Background

          Injection drug use (IDU) and heterosexual virus transmission both contribute to the growing mixed HIV epidemics in Eastern Europe and Central Asia. In Ukraine—chosen in this study as a representative country—IDU-related risk behaviors cause half of new infections, but few injection drug users (IDUs) receive methadone substitution therapy. Only 10% of eligible individuals receive antiretroviral therapy (ART). The appropriate resource allocation between these programs has not been studied. We estimated the effectiveness and cost-effectiveness of strategies for expanding methadone substitution therapy programs and ART in mixed HIV epidemics, using Ukraine as a case study.

          Methods and Findings

          We developed a dynamic compartmental model of the HIV epidemic in a population of non-IDUs, IDUs using opiates, and IDUs on methadone substitution therapy, stratified by HIV status, and populated it with data from the Ukraine. We considered interventions expanding methadone substitution therapy, increasing access to ART, or both. We measured health care costs, quality-adjusted life years (QALYs), HIV prevalence, infections averted, and incremental cost-effectiveness. Without incremental interventions, HIV prevalence reached 67.2% (IDUs) and 0.88% (non-IDUs) after 20 years. Offering methadone substitution therapy to 25% of IDUs reduced prevalence most effectively (to 53.1% IDUs, 0.80% non-IDUs), and was most cost-effective, averting 4,700 infections and adding 76,000 QALYs compared with no intervention at US$530/QALY gained. Expanding both ART (80% coverage of those eligible for ART according to WHO criteria) and methadone substitution therapy (25% coverage) was the next most cost-effective strategy, adding 105,000 QALYs at US$1,120/QALY gained versus the methadone substitution therapy-only strategy and averting 8,300 infections versus no intervention. Expanding only ART (80% coverage) added 38,000 QALYs at US$2,240/QALY gained versus the methadone substitution therapy-only strategy, and averted 4,080 infections versus no intervention. Offering ART to 80% of non-IDUs eligible for treatment by WHO criteria, but only 10% of IDUs, averted only 1,800 infections versus no intervention and was not cost effective.

          Conclusions

          Methadone substitution therapy is a highly cost-effective option for the growing mixed HIV epidemic in Ukraine. A strategy that expands both methadone substitution therapy and ART to high levels is the most effective intervention, and is very cost effective by WHO criteria. When expanding ART, access to methadone substitution therapy provides additional benefit in infections averted. Our findings are potentially relevant to other settings with mixed HIV epidemics.

          Please see later in the article for the Editors' Summary

          Editors' Summary

          Background

          HIV epidemics in Eastern Europe and Central Asia are mainly driven by increasing use of injection drugs combined with heterosexual transmission. In the Ukraine, in 2007, there were 82,000 officially registered people living with HIV—three times the number registered in 1999—and an estimated 395,000 HIV infected adults. The epidemic in Ukraine, like other countries in the region, is concentrated in at-risk populations, particularly people who inject drugs: in 2007, an estimated 390,000 Ukrainians were injecting drugs, an increase in drug use over the previous decade, not only in Ukraine, but in other former USSR states, owing to the easy availability of precursors for injection drugs in a climate of economic collapse.

          The common practices of people who inject drugs in Ukraine and in other countries in the region, such as social injecting, syringe sharing, and using common containers, increase the risk of transmitting HIV. Public health interventions such as needle exchange can limit these risk factors and have been gradually implemented in these countries. In 2007, Ukraine approved the use of methadone substitution therapy and the current target is for 11,000 people who inject drugs to be enrolled in substitution therapy by 2011. Furthermore, since treatment for HIV-infected individuals is also necessary, national HIV control plans included a target of 90% antiretroviral therapy (ART) coverage by 2010 but in 2007 less than 10% of the 91,000 eligible people received treatment. Although the number of people who inject drugs and who receive ART is unknown, physicians are often reluctant to treat people who inject drugs using ART owing to alleged poor compliance.

          Why Was This Study Done?

          As resources for HIV interventions in the region are limited, it is important to investigate the appropriate balance between investments in methadone substitution therapy and ART in order to maximize benefits to public health. Several studies have analyzed the cost effectiveness of methadone substitution therapy in similar settings but have not considered tradeoffs between ART and methadone substitution therapy. Therefore, to provide insights into the appropriate public health investment in methadone substitution therapy and ART in Ukraine, the researchers evaluated the public health effectiveness and cost effectiveness of different strategies for scaling up methadone substitution therapy and/or expanding ART.

          What Did the Researchers Do and Find?

          The researchers developed a model to accommodate different population groups: people who inject drugs on substitution therapy with methadone; people who inject opiates and do not take any substitution therapy; and people who do not inject any drugs, hence do not need substitution therapy. The researchers inputted Ukraine country-level data into this model and used current HIV trends in Ukraine to make rational assumptions on possible future trends and scenarios. They considered scenarios expanding methadone substitution therapy availability, increasing acces to ART, or both. Then, the researchers measured health care costs, quality-adjusted life years (QALYs), HIV prevalence, infections averted, and incremental cost effectiveness for the different scenarios. They found that after 20 years, HIV prevalence reached 67.2% in people who inject drugs and 0.88% in people who do not inject drugs without further interventions. Offering methadone substitution therapy to 25% of people who inject drugs was the most effective strategy in reducing prevalence of HIV and was also the most cost effective, averting 4,700 infections and adding 75,700 QALYs versus the status quo at $530/QALY gained. Expanding both methadone substitution therapy and ART was also a highly cost effective option, adding 105,000 QALYs at US$1,120/QALY gained versus the methadone substitution therapy-only strategy. Offering ART to 80% of eligible people who did not inject drugs, and 10% of people who injected drugs averted only 1,800 infections, and added 76,400 QALYs at $1,330/QALY gained.

          What Do These Findings Mean?

          The results show that methadone substitution-focused therapeutic scenarios are the most cost effective, and that benefits increase with the scale of the project, even among people who do not inject drugs. This makes a methadone substitution strategy a highly cost-effective option for addressing the growing HIV epidemic in Ukraine. Therefore, if it is not feasible to invest in large-scale methadone substitution programs for any reason, political circumstances for example, providing as much methadone substitution as is acceptable is still desirable. While substitution therapy appears to avert the most HIV infections, expanded ART provides the largest total increase in QALYs. Thus, methadone substitution therapy and ART offer complementary benefits. Because the HIV epidemic in Ukraine is representative of the HIV epidemic in Eastern Europe and Central Asia, the cost-effective strategies that the researchers have identified may help inform all decision makers faced with a mixed HIV epidemic.

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          Most cited references21

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          Prognosis of HIV-1-infected patients starting highly active antiretroviral therapy: a collaborative analysis of prospective studies.

          Insufficient data are available from single cohort studies to allow estimation of the prognosis of HIV-1 infected, treatment-naive patients who start highly active antiretroviral therapy (HAART). The ART Cohort Collaboration, which includes 13 cohort studies from Europe and North America, was established to fill this knowledge gap. We analysed data on 12,574 adult patients starting HAART with a combination of at least three drugs. Data were analysed by intention-to-continue-treatment, ignoring treatment changes and interruptions. We considered progression to a combined endpoint of a new AIDS-defining disease or death, and to death alone. The prognostic model that generalised best was a Weibull model, stratified by baseline CD4 cell count and transmission group. FINDINGS During 24,310 person-years of follow up, 1094 patients developed AIDS or died and 344 patients died. Baseline CD4 cell count was strongly associated with the probability of progression to AIDS or death: compared with patients starting HAART with less than 50 CD4 cells/microL, adjusted hazard ratios were 0.74 (95% CI 0.62-0.89) for 50-99 cells/microL, 0.52 (0.44-0.63) for 100-199 cells/microL, 0.24 (0.20-0.30) for 200-349 cells/microL, and 0.18 (0.14-0.22) for 350 or more CD4 cells/microL. Baseline HIV-1 viral load was associated with a higher probability of progression only if 100,000 copies/microL or above. Other independent predictors of poorer outcome were advanced age, infection through injection-drug use, and a previous diagnosis of AIDS. The probability of progression to AIDS or death at 3 years ranged from 3.4% (2.8-4.1) in patients in the lowest-risk stratum for each prognostic variable, to 50% (43-58) in patients in the highest-risk strata. The CD4 cell count at initiation was the dominant prognostic factor in patients starting HAART. Our findings have important implications for clinical management and should be taken into account in future treatment guidelines.
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            Generalized cost-effectiveness analysis for national-level priority-setting in the health sector

            Cost-effectiveness analysis (CEA) is potentially an important aid to public health decision-making but, with some notable exceptions, its use and impact at the level of individual countries is limited. A number of potential reasons may account for this, among them technical shortcomings associated with the generation of current economic evidence, political expediency, social preferences and systemic barriers to implementation. As a form of sectoral CEA, Generalized CEA sets out to overcome a number of these barriers to the appropriate use of cost-effectiveness information at the regional and country level. Its application via WHO-CHOICE provides a new economic evidence base, as well as underlying methodological developments, concerning the cost-effectiveness of a range of health interventions for leading causes of, and risk factors for, disease. The estimated sub-regional costs and effects of different interventions provided by WHO-CHOICE can readily be tailored to the specific context of individual countries, for example by adjustment to the quantity and unit prices of intervention inputs (costs) or the coverage, efficacy and adherence rates of interventions (effectiveness). The potential usefulness of this information for health policy and planning is in assessing if current intervention strategies represent an efficient use of scarce resources, and which of the potential additional interventions that are not yet implemented, or not implemented fully, should be given priority on the grounds of cost-effectiveness. Health policy-makers and programme managers can use results from WHO-CHOICE as a valuable input into the planning and prioritization of services at national level, as well as a starting point for additional analyses of the trade-off between the efficiency of interventions in producing health and their impact on other key outcomes such as reducing inequalities and improving the health of the poor.
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              Calculating QALYs, comparing QALY and DALY calculations.

              F Sassi (2006)
              Quality-adjusted life years (QALYs) have been used in the assessment of health interventions for three decades. The popularity of the QALY approach has been constantly increasing, although the debate on its theoretical underpinnings and practical implications is still ongoing. Disability-adjusted life years (DALYs), also widely debated, were shaped some 20 years later, broadly within the same conceptual framework but with a number of important differences. This paper provides a comprehensive formulation of QALY calculation methods, offering practical instruments for assessing the impact of health interventions, similar to those made available elsewhere for calculating DALYs. Systematic differences between QALYs and DALYs are explained by reference to two examples: the prevention of tuberculosis and the treatment of bipolar depression. When a health intervention is aimed at preventing or treating a non-fatal disease, the relationship between QALYs gained and DALYs saved depends on age of onset and duration of the disease, as well as the quality of life and disability weights. In the case of a potentially fatal disease, a larger number of factors may determine differences between outcomes assessed with the two metrics. The relative importance of some of these factors is discussed and illustrated graphically in the paper. Understanding similarities and differences between QALYs and DALYs is important to researchers and policy makers, for a sound interpretation of the evidence on the outcomes of health interventions.
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                Author and article information

                Contributors
                Role: Academic Editor
                Journal
                PLoS Med
                PLoS
                plosmed
                PLoS Medicine
                Public Library of Science (San Francisco, USA )
                1549-1277
                1549-1676
                March 2011
                March 2011
                1 March 2011
                : 8
                : 3
                : e1000423
                Affiliations
                [1 ]Department of Management Science and Engineering, Stanford University, Stanford, California, United States of America
                [2 ]Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
                [3 ]Center for Health Policy and the Center for Primary Care and Outcomes Research, Stanford University, Stanford, California, United States of America
                Johns Hopkins University, United States of America
                Author notes

                ICMJE criteria for authorship read and met: SSA DKO MLB. Agree with the manuscript's results and conclusions: SSA DKO MLB. Designed the experiments/the study: SSA DKO MLB. Analyzed the data: SSA. Wrote the first draft of the paper: SSA. Contributed to the writing of the paper: SSA DKO MLB. Designed the model and identified/collected the parameters for the model: SSA. Helped conceptualize the design of the analysis: DKO. Helped define the research topic and develop the modeling methodology: MLB.

                Article
                10-PLME-RA-4079R4
                10.1371/journal.pmed.1000423
                3046988
                21390264
                935c597c-a0f9-45ec-8eb0-740db15cc00a
                This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
                History
                : 11 February 2010
                : 19 January 2011
                Page count
                Pages: 15
                Categories
                Research Article
                Infectious Diseases/HIV Infection and AIDS
                Mathematics
                Mental Health/Substance Abuse
                Non-Clinical Medicine/Health Economics
                Non-Clinical Medicine/Health Policy
                Public Health and Epidemiology/Health Policy
                Public Health and Epidemiology/Health Services Research and Economics
                Public Health and Epidemiology/Infectious Diseases
                Public Health and Epidemiology/Preventive Medicine

                Medicine
                Medicine

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