Cost-effectiveness of antiretroviral regimens in the World Health Organization's treatment guidelines: a South African analysis

Annual Costs Incurred in Managing Adverse Drug Reactions Attributable to Fixed-Dose Combination Highly Active Antiretroviral Therapy in an Outpatient Antiretroviral Clinic in Gauteng: A Budget Impact Analysis

OBJECTIVES

This study aimed to identify adverse drug reactions (ADRs) attributable to tenofovir (TDF)- and zidovudine (AZT)-based fixed-dose combinations of highly active antiretroviral (ARV) therapy and subsequently determine the annual costs incurred in managing these ADRs and the budget implications in an outpatient ARV clinic in Mamelodi, Pretoria.

METHODS

This retrospective cohort study reviewed deidentified clinical data for ADRs. Medical charts of human immunodeficiency virus-positive patients, who were receiving either TDF- or AZT-based fixed-dose combinations of ARV therapy, were analyzed. Costs were converted to US dollars using the rate of US$1 equivalent to ZAR14.3853. Based on the costs and the incidence rates of ADRs observed in the analysis, a decision tree model was established to estimate the cost impact of ADR management on the clinic's budget.

RESULTS

A total of 469 patient files were analyzed (62% female vs 38% male). The mean age at the start of ARV therapy for the cohort was 36.6 years (95% confidence interval 35.74-37.45), and the mean baseline CD4 count was 380 (95% confidence interval 343-418). The incidence of ADRs to TDF- or AZT-based fixed-dose combinations of ARV therapy was found to be 24.95%. The study revealed that US$29.70 was the cost attributed to ADRs owing to TDF-based regimens, whereas US$32.53 was the cost attributed to ADRs owing to AZT-based regimens, per patient, annually. Costs attributed to gastrointestinal-related ADRs were the highest in comparison with other ADRs. The estimated total cost of ADRs attributed to AZT-based therapy was US$556.40, and the estimated total cost of ADRs attributed to TDF-based ARV therapy per annum was US$2348.80 for the 1221 patients who started receiving ARV therapy between July 2017 and June 2018 at the clinic.

CONCLUSIONS

Despite the estimated costs related to ADRs in the study being lower than those in similar studies, there remains a notable budget impact, particularly in a resource-limited setting. The study findings allow for improved budget forecasts in an ARV clinic setting.

The per-patient costs of HIV services in South Africa: Systematic review and application in the South African HIV Investment Case

Background

In economic analyses of HIV interventions, South Africa is often used as a case in point, due to the availability of good epidemiological and programme data and the global relevance of its epidemic. Few analyses however use locally relevant cost data. We reviewed available cost data as part of the South African HIV Investment Case, a modelling exercise to inform the optimal use of financial resources for the country’s HIV programme.

Methods

We systematically reviewed publication databases for published cost data covering a large range of HIV interventions and summarised relevant unit costs (cost per person receiving a service) for each. Where no data was found in the literature, we constructed unit costs either based on available information regarding ingredients and relevant public-sector prices, or based on expenditure records.

Results

Only 42 (5%) of 1,047 records included in our full-text review reported primary cost data on HIV interventions in South Africa, with 71% of included papers covering ART. Other papers detailed the costs of HCT, MMC, palliative and inpatient care; no papers were found on the costs of PrEP, social and behaviour change communication, and PMTCT. The results informed unit costs for 5 of 11 intervention categories included in the Investment Case, with the remainder costed based on ingredients (35%) and expenditure data (10%).

Conclusions

A large number of modelled economic analyses of HIV interventions in South Africa use as inputs the same, often outdated, cost analyses, without reference to additional literature review. More primary cost analyses of non-ART interventions are needed.

Efficacy and Safety of Tenofovir Disoproxil Fumarate Versus Low-Dose Stavudine Over 96 Weeks: A Multicountry Randomized, Noninferiority Trial

BACKGROUND

Reducing doses of antiretroviral drugs, including stavudine (d4T), may lower toxicity, while preserving efficacy. There are substantial concerns about renal and bone toxicities of tenofovir disoproxil fumarate (TDF).

SETTING

HIV-1-infected treatment-naive adults in India, South Africa, and Uganda.

METHODS

A phase-4, 96-week, randomized, double-blind, noninferiority trial compared d4T 20 mg twice daily and TDF, taken in combination with lamivudine (3TC) and efavirenz (EFV). The primary endpoint was the proportion of participants with HIV-1 RNA <50 copies per milliliter at 48 weeks. Adverse events assessments included measures of bone density and body fat. The trial is registered on Clinicaltrials.gov (NCT02670772).

RESULTS

Between 2012 and 2014, 536 participants were recruited per arm. At week 96, trial completion rates were 75.7% with d4T/3TC/EFV (n = 406) and 82.1% with TDF/3TC/EFV (n = 440, P = 0.011). Noncompletion was largely due to virological failure [6.2% (33) with d4T/3TC/EFV versus 5.4% (29) with TDF/3TC/EFV; P = 0.60]. For the primary endpoint, d4T/3TC/EFV was noninferior to TDF/3TC/EFV (79.3%, 425/536 versus 80.8% 433/536; difference = -1.49%, 95% CI: -6.3 to 3.3; P < 0.001). Drug-related adverse event discontinuations were higher with d4T (6.7%, 36), than TDF (1.1%, 6; P < 0.001). Lipodystrophy was more common with d4T (5.6%, 30) than TDF (0.2%, 1; P < 0.001). Creatinine clearance increased in both arms, by 18.1 mL/min in the d4T arm and 14.2 mL/min with TDF (P = 0.03). Hip bone density measures, however, showed greater loss with TDF.

CONCLUSIONS

Low-dose d4T combined with 3TC/EFV demonstrated noninferior virological efficacy compared with TDF/3TC/EFV, but mitochondrial toxicity remained high. Little renal toxicity occurred in either arm. Implications of bone mineral density changes with TDF warrant investigation.

Cost-Effectiveness of Cervical Cancer Screening in Women Living With HIV in South Africa: A Mathematical Modeling Study

BACKGROUND

Women with HIV face an increased risk of human papillomavirus (HPV) acquisition and persistence, cervical intraepithelial neoplasia, and invasive cervical cancer. Our objective was to determine the cost-effectiveness of different cervical cancer screening strategies among women with HIV in South Africa.

METHODS

We modified a mathematical model of HPV infection and cervical disease to reflect coinfection with HIV. The model was calibrated to epidemiologic data from HIV-infected women in South Africa. Clinical and economic data were drawn from in-country data sources. The model was used to project reductions in the lifetime risk of cervical cancer and incremental cost-effectiveness ratios (ICERs) of Pap and HPV DNA screening and management algorithms beginning at HIV diagnosis, at 1-, 2-, or 3-year intervals. Strategies with an ICER below South Africa's 2016 per capita gross domestic product (US$5270) were considered "cost-effective."

RESULTS

HPV testing followed by treatment (test-and-treat) at 2-year intervals was the most effective strategy that was also cost-effective, reducing lifetime cancer risk by 56.6% with an ICER of US$3010 per year of life saved. Other cost-effective strategies included Pap (referral threshold: HSIL+) at 1-, 2-, and 3-year intervals, and HPV test-and-treat at 3-year intervals. Pap (ASCUS+), HPV testing with 16/18 genotyping, and HPV testing with Pap or visual triage of HPV-positive women were less effective and more costly than alternatives.

CONCLUSIONS

Considering per capita gross domestic product as the benchmark for cost-effectiveness, HPV test-and-treat is optimal in South Africa. At lower cost-effectiveness benchmarks, Pap (HSIL+) would be optimal.

HIV-1 strains belonging to large phylogenetic clusters show accelerated escape from integrase inhibitors in cell culture compared with viral isolates from singleton/small clusters

Objectives: Viral phylogenetics revealed two patterns of HIV-1 spread among MSM in Quebec. While most HIV-1 strains (n = 2011) were associated with singleton/small clusters (cluster size 1–4), 30 viral lineages formed large networks (cluster size 20–140), contributing to 42% of diagnoses between 2011 and 2015. Herein, tissue culture selections ascertained if large cluster lineages possessed higher replicative fitness than singleton/small cluster isolates, allowing for viral escape from integrase inhibitors.

Methods: Primary HIV-1 isolates from large 20+ cluster (n = 11) or singleton/small cluster (n = 6) networks were passagedin vitro in escalating concentrations of dolutegravir, elvitegravir and lamivudine for 24–36 weeks. Sanger and deep sequencing assessed genotypic changes under selective drug pressure.

Results: Large cluster HIV-1 isolates selected for resistance to dolutegravir, elvitegravir and lamivudine faster than HIV-1 strains forming small clusters. With dolutegravir, large cluster HIV-1 variants acquired solitary R263K (n = 7), S153Y (n = 1) or H51Y (n = 1) mutations as the dominant quasi-species within 8–12 weeks as compared with small cluster lineages where R263K (n = 1/6), S153Y (1/6) or WT species (4/6) were observed after 24 weeks. Interestingly, dolutegravir-associated mutations compromised viral replicative fitness, precluding escalations in concentrations beyond 5–10 nM. With elvitegravir, large cluster variants more rapidly acquired first mutations (T66I, A92G, N155H or S147G) by week 8 followed by sequential accumulation of multiple mutations leading to viral escape (>10 μM) by week 24.

Conclusions: Further studies are needed to understand virological features of large cluster viruses that may favour their transmissibility, replicative competence and potential to escape selective antiretroviral drug pressure.

Active Surveillance versus Spontaneous Reporting for First-Line Antiretroviral Medicines in Namibia: A Cost-Utility Analysis

INTRODUCTION

Active surveillance pharmacovigilance is a systematic approach to medicine safety assessment and health systems strengthening, but has not been widely implemented in low- and middle-income countries. This study aimed to assess the cost effectiveness of a national active surveillance pharmacovigilance system for highly active antiretroviral therapy (HAART) compared with the existing spontaneous reporting system in Namibia.

METHODS

A cost-utility analysis from a governmental perspective compared active surveillance pharmacovigilance to spontaneous reporting. Data from a sentinel site active surveillance program in Namibia from August 2012 to April 2013 was projected to all HIV-infected adults initiating HAART in Namibia. Costs (pharmacovigilance program, HAART, adverse event [AE] treatment), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs, dollars/QALY) were evaluated. Analysis was completed for (i) cohort analysis: a single cohort beginning HAART in 1 year in Namibia followed over their remaining lifetime, and (ii) population analysis: patients continued to enter and leave care and treatment over 10 years.

RESULTS

For the cohort analysis, totals were US$21,267,902 (2015 US dollars) and 116,224 QALYs for care and treatment under active surveillance pharmacovigilance versus US$15,257,381 and 116,122 QALYs for care and treatment under spontaneous reporting pharmacovigilance, resulting in an ICER of US$58,867/QALY for active surveillance compared with spontaneous reporting pharmacovigilance. The population analysis ICER was US$4989/QALY. Results were sensitive to quality of life associated with AEs.

CONCLUSION

Active surveillance pharmacovigilance was projected to be highly cost effective to improve treatment for HIV in Namibia. Active surveillance pharmacovigilance may be valuable to improve lives of HIV patients and more efficiently allocate health resources in Namibia.

The Cost-effectiveness of a Point-of-Care Paper Transaminase Test for Monitoring Treatment of HIV/TB Co-Infected Persons

Background

Persons with HIV and tuberculosis (TB) co-infection require transaminase monitoring while on hepatotoxic medications. A novel paper-based, point-of-care transaminase test is in development at an anticipated cost of $1 per test.

Methods

To project long-term clinical outcomes and estimate the cost-effectiveness of using a paper-based fingerstick test to monitor for drug-induced liver injury (DILI), as compared with automated testing and with no laboratory monitoring. The design was a decision analytic model, including deterministic and probabilistic sensitivity analyses. Data sources were observational cohorts and a validation study of the paper-based test. The target population was HIV/TB co-infected persons in South Africa on antiretroviral therapy who were initiating TB therapy. Interventions: (1) clinical (no laboratory) monitoring; (2) monitoring using the paper-based test with a ≥120 IU/mL threshold for positivity; (3) monitoring using the paper-based test with a ≥200 IU/mL threshold for positivity; (4) monitoring using the paper-based test using 1 of 3 categories: <120 IU/mL, 120 to 200 IU/mL, and >200 IU/mL (“bin placement”); (5) monitoring using automated ALT testing using the same 3 categories (“automated testing”). The outcome measures were discounted quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs).

Results

The ICER of automated testing was $5180/QALY. Use of the paper-based test with the bin placement strategy was cost-effective compared with clinical monitoring alone.

Conclusion

At its current performance, monthly DILI monitoring by bin placement using the paper-based test was cost-effective, compared with clinical monitoring, in HIV/TB co-infected persons in South Africa.

Spectroscopic and molecular docking studies on the interaction of antiviral drug nevirapine with calf thymus DNA

The interaction of calf thymus DNA with nevirapine at physiological pH was studied by using absorption, circular dichroism, viscosity, differential pulse voltammetry, fluorescence techniques, salt effect studies and computational methods. The drug binds to ct-DNA in a groove binding mode, as shown by slight variation in the viscosity of ct-DNA. Furthermore, competitive fluorimetric studies with Hoechst 33258 indicate that nevirapine binds to DNA via groove binding. Moreover, the structure of nevirapine was optimized by DFT calculations and was used for the molecular docking calculations. The molecular docking results suggested that nevirapine prefers to bind on the minor groove of ct-DNA.

Cost-effectiveness analysis of the national decentralization policy of antiretroviral treatment programme in Zambia

Background

In resource-limited settings with a high prevalence of human immunodeficiency virus (HIV) infection such as Zambia, decentralization of HIV/acquired immunodeficiency syndrome (HIV/AIDS) treatment and care with effective use of resources is a cornerstone of universal treatment and care.

Objectives

This research aims to analyse the cost effectiveness of the National Mobile Antiretroviral Therapy (ART) Services Programme in Zambia as a means of decentralizing ART services.

Methods

Cost-effectiveness analyses were performed using a decision analytic model and Markov model to compare the original ART programme, ‘Hospital-based ART’, with the intervention programme, Hospital-based plus ‘Mobile ART’, from the perspective of the district government health office in Zambia. The total cost of ART services, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) were examined.

Results

The mean annual per-patient costs were 1259.16 USD for the original programme and 2601.02 USD for the intervention programme, while the mean number of QALYs was 6.81 for the original and 7.27 for the intervention programme. The ICER of the intervention programme relative to the original programme was 2965.17 USD/QALY, which was much below the willingness-to-pay (WTP), or three times the GDP per capita (4224 USD), but still over the GDP per capita (1408 USD). In the sensitivity analysis, the ICER of the intervention programme did not substantially change.

Conclusion

The National Mobile ART Services Programme in Zambia could be a cost-effective approach to decentralizing ART services into rural areas in Zambia. This programme could be expanded to more districts where it has not yet been introduced to improve access to ART services and the health of people living with HIV (PLHIV) in rural areas.

Electronic supplementary material

The online version of this article (doi:10.1186/s12962-017-0065-8) contains supplementary material, which is available to authorized users.

Large cluster outbreaks sustain the HIV epidemic among MSM in Quebec

OBJECTIVE

HIV-1 epidemics among MSM remain unchecked despite advances in treatment and prevention paradigms. This study combined viral phylogenetic and behavioural risk data to better understand underlying factors governing the temporal growth of the HIV epidemic among MSM in Quebec (2002-2015).

METHODS

Phylogenetic analysis of pol sequences was used to deduce HIV-1 transmission dynamics (cluster size, size distribution and growth rate) in first genotypes of treatment-naïve MSM (2002-2015, n = 3901). Low sequence diversity of first genotypes (0-0.44% mixed base calls) was used as an indication of early-stage infection. Behavioural risk data were obtained from the Montreal rapid testing site and primary HIV-1-infection cohorts.

RESULTS

Phylogenetic analyses uncovered high proportion of clustering of new MSM infections. Overall, 27, 45, 48, 53 and 57% of first genotypes within one (singleton, n = 1359), 2-4 (n = 692), 5-9 (n = 367), 10-19 (n = 405) and 20+ (n = 1277) cluster size groups were early infections (<0.44% diversity). Thirty viruses within large 20+ clusters disproportionately fuelled the epidemic, representing 13, 25 and 42% of infections, first genotyped in 2004-2007 (n = 1314), 2008-2011 (n = 1356) and 2012-2015 (n = 1033), respectively. Of note, 35, 21 and 14% of MSM belonging to 20+, 2-19 and one (singleton) cluster groups were under 30 years of age, respectively. Half of persons seen at the rapid testing site (2009-2011, n = 1781) were untested in the prior year. Poor testing propensity was associated with fewer reported partnerships.

CONCLUSION

Addressing the heterogeneity in transmission dynamics among HIV-1-infected MSM populations may help guide testing, treatment and prevention strategies.

Multicenter study of skin rashes and hepatotoxicity in antiretroviral-naïve HIV-positive patients receiving non-nucleoside reverse-transcriptase inhibitor plus nucleoside reverse-transcriptase inhibitors in Taiwan

OBJECTIVES

Two nucleos(t)ide reverse-transcriptase inhibitors (NRTIs) plus 1 non-NRTI (nNRTI) remain the preferred or alternative combination antiretroviral therapy (cART) for antiretroviral-naive HIV-positive patients in Taiwan. The three most commonly used nNRTIs are nevirapine (NVP), efavirenz (EFV) and rilpivirine (RPV). This study aimed to determine the incidences of hepatotoxicity and skin rashes within 4 weeks of initiation of cART containing 1 nNRTI plus 2 NRTIs.

METHODS

Between June, 2012 and November, 2015, all antiretroviral-naive HIV-positive adult patients initiating nNRTI-containing cART at 8 designated hospitals for HIV care were included in this retrospective observational study. According to the national HIV treatment guidelines, patients were assessed at baseline, 2 and 4 weeks of cART initiation, and subsequently every 8 to 12 weeks. Plasma HIV RNA load, CD4 cell count and aminotransferases were determined. The toxicity grading scale of the Division of AIDS (DAIDS) 2014 was used for reporting clinical and laboratory adverse events.

RESULTS

During the 3.5-year study period, 2,341 patients initiated nNRTI-containing cART: NVP in 629 patients, EFV 1,363 patients, and RPV 349 patients. Rash of any grade occurred in 14.1% (n = 331) of the patients. In multiple logistic regression analysis, baseline CD4 cell counts (per 100-cell/μl increase, adjusted odds ratio [AOR], 1.125; 95% confidence interval [95% CI], 1.031-1.228) and use of NVP (AOR, 2.443; 95% CI, 1.816-3.286) (compared with efavirenz) were independently associated with the development of skin rashes. Among the 1,455 patients (62.2%) with aminotransferase data both at baseline and week 4, 72 (4.9%) developed grade 2 or greater hepatotoxicity. In multiple logistic regression analysis, presence of antibody for hepatitis C virus (HCV) (AOR, 2.865; 95% CI, 1.439-5.704) or hepatitis B surface antigen (AOR, 2.397; 95% CI, 1.150-4.997), and development of skin rashes (AOR, 2.811; 95% CI, 1.051-7.521) were independently associated with the development of hepatotoxicity.

CONCLUSIONS

The baseline CD4 cell counts and use of NVP were associated with increased risk of skin rashes, while hepatotoxicity was independently associated with HCV or hepatitis B virus coinfection, and development of skin rashes in antiretroviral-naïve HIV-positive Taiwanese patients within 4 weeks of initiation of nNRTI-containing regimens.

Mortality along the continuum of HIV care in Rwanda: a model-based analysis

Background

HIV is the leading cause of death among adults in sub-Saharan Africa. However, mortality along the HIV care continuum is poorly described. We combine demographic, epidemiologic, and health services data to estimate where are people with HIV dying along Rwanda’s care continuum.

Methods

We calibrated an age-structured HIV disease and transmission stochastic simulation model to the epidemic in Rwanda. We estimate mortality among HIV-infected individuals in the following states: untested, tested without establishing care in an antiretroviral therapy (ART) program (unlinked), in care before initiating ART (pre-ART), lost to follow-up (LTFU) following ART initiation, and retained in active ART care. We estimated mortality among people living with HIV in Rwanda through 2025 under current conditions, and with improvements to the HIV care continuum.

Results

In 2014, the greatest portion of deaths occurred among those untested (35.4%), followed by those on ART (34.1%), reflecting the large increase in the population on ART. Deaths among those LTFU made up 11.8% of all deaths among HIV-infected individuals in 2014, and in the base case this portion increased to 18.8% in 2025, while the contribution to mortality declined among those untested, unlinked, and in pre-ART. In our model only combined improvements to multiple aspects of the HIV care continuum were projected to reduce the total number of deaths among those with HIV, estimated at 8177 in 2014, rising to 10,659 in the base case, and declining to 5,691 with combined improvements in 2025.

Conclusion

Mortality among those untested for HIV contributes a declining portion of deaths among HIV-infected individuals in Rwanda, but the portion of deaths among those LTFU is expected to increase the most over the next decade. Combined improvements to the HIV care continuum might be needed to reduce the number of deaths among those with HIV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-2052-7) contains supplementary material, which is available to authorized users.

Nevirapine modulation of paraoxonase-1 in the liver: An in vitro three-model approach

INTRODUCTION

Nevirapine is associated with severe hepatotoxicity, through the formation of reactive metabolites. Paraoxonase-1 (PON-1) is a promiscuous enzyme involved in the metabolism of xeno- and endobiotics and proposed as a biomarker of hepatotoxicity. The aim of this work was to explore the effects of nevirapine and its phase I metabolites, 2-hydroxy-nevirapine and 12-hydroxy-nevirapine, on PON-1 activities.

MATERIAL AND METHODS

2D and 3D primary cultures of rat hepatocytes, and also HepG2 2D cell cultures, were exposed to nevirapine, 2-hydroxy-nevirapine, and 12-hydroxy-nevirapine. The paraoxonase (POase), arylesterase (AREase) and lactonase (LACase) activities of PON-1 were quantified.

RESULTS

Effects of nevirapine and its metabolites were only observed in the 3D cell model. Both nevirapine and 12-hydroxy-nevirapine increased POase (p<0.05, p<0.01) and LACase activities (p<0.05, p<0.001). The AREase activity was increased only upon 12-hydroxy-nevirapine exposure (p<0.01). These modulatory effects were observed at 300μM concentrations of nevirapine and 12-hydroxy-nevirapine.

CONCLUSIONS

The formation of 12-hydroxy-nevirapine seems to be the main factor responsible for the increase of PON-1 activities induced by nevirapine exposure. This effect was only observed in the 3D model, suggesting that an in vivo-like system is necessary for this modulation to occur. The present data suggest that the 3D model is a more suitable in vitro model than the conventional ones to explore drug effects on PON-1.

The Impact of Company-Level ART Provision to a Mining Workforce in South Africa: A Cost-Benefit Analysis

BACKGROUND

HIV impacts heavily on the operating costs of companies in sub-Saharan Africa, with many companies now providing antiretroviral therapy (ART) programmes in the workplace. A full cost-benefit analysis of workplace ART provision has not been conducted using primary data. We developed a dynamic health-state transition model to estimate the economic impact of HIV and the cost-benefit of ART provision in a mining company in South Africa between 2003 and 2022.

METHODS AND FINDINGS

A dynamic health-state transition model, called the Workplace Impact Model (WIM), was parameterised with workplace data on workforce size, composition, turnover, HIV incidence, and CD4 cell count development. Bottom-up cost analyses from the employer perspective supplied data on inpatient and outpatient resource utilisation and the costs of absenteeism and replacement of sick workers. The model was fitted to workforce HIV prevalence and separation data while incorporating parameter uncertainty; univariate sensitivity analyses were used to assess the robustness of the model findings. As ART coverage increases from 10% to 97% of eligible employees, increases in survival and retention of HIV-positive employees and associated reductions in absenteeism and benefit payments lead to cost savings compared to a scenario of no treatment provision, with the annual cost of HIV to the company decreasing by 5% (90% credibility interval [CrI] 2%-8%) and the mean cost per HIV-positive employee decreasing by 14% (90% CrI 7%-19%) by 2022. This translates into an average saving of US$950,215 (90% CrI US$220,879-US$1.6 million) per year; 80% of these cost savings are due to reductions in benefit payments and inpatient care costs. Although findings are sensitive to assumptions regarding incidence and absenteeism, ART is cost-saving under considerable parameter uncertainty and in all tested scenarios, including when prevalence is reduced to 1%-except when no benefits were paid out to employees leaving the workforce and when absenteeism rates were half of what data suggested. Scaling up ART further through a universal test and treat strategy doubles savings; incorporating ART for family members reduces savings but is still marginally cost-saving compared to no treatment. Our analysis was limited to the direct cost of HIV to companies and did not examine the impact of HIV prevention policies on the miners or their families, and a few model inputs were based on limited data, though in sensitivity analysis our results were found to be robust to changes to these inputs along plausible ranges.

CONCLUSIONS

Workplace ART provision can be cost-saving for companies in high HIV prevalence settings due to reductions in healthcare costs, absenteeism, and staff turnover. Company-sponsored HIV counselling and voluntary testing with ensuing treatment of all HIV-positive employees and family members should be implemented universally at workplaces in countries with high HIV prevalence.

Cost-Effectiveness of Initiating Antiretroviral Therapy at Different Points in TB Treatment in HIV-TB Coinfected Ambulatory Patients in South Africa

OBJECTIVE

Initiation of antiretroviral therapy (ART) during tuberculosis (TB) treatment improves survival in TB-HIV coinfected patients. In patients with CD4 counts <50 cells per cubic millimeter, there is a substantial clinical and survival benefit of early ART initiation. The purpose of this study was to assess the costs and cost-effectiveness of starting ART at various time points during TB treatment in patients with CD4 counts ≥50 cells per cubic millimeter.

METHODS

In the SAPiT trial, 642 HIV-TB coinfected patients were randomized to 3 arms: receiving ART within 4 weeks of starting TB treatment (early treatment arm; Arm-1), after the intensive phase of TB treatment (late treatment arm; Arm-2), or after completing TB treatment (sequential arm; Arm-3). Direct health care costs were measured from a provider perspective using a micro-costing approach. The incremental cost per death averted was calculated using the trial outcomes.

RESULTS

For patients with CD4 count ≥50 cells per cubic millimeter, median monthly variable costs per patient were US $116, US $113, and US $102 in Arm-1, Arm-2 and Arm-3, respectively. There were 12 deaths in 177 patients in Arm-1, 8 deaths in 180 patients in the Arm-2, and 19 deaths in 172 patients in Arm-3. Although the costs were lower in Arm-3, it had a substantially higher mortality rate. The incremental cost per death averted associated with moving from Arm-3 to Arm-2 was US $4199. There was no difference in mortality between Arm-1 and Arm-2, but Arm-1 was slightly more expensive.

CONCLUSIONS

Initiation of ART after the completion of the intensive phase of TB treatment is cost-effective for patients with CD4 counts ≥50 cells per cubic millimeter.

Predictors of Treatment Failure in HIV-Positive Children Receiving Combination Antiretroviral Therapy: Cohort Data From Mozambique and Uganda

BACKGROUND

Delays detecting treatment failure and switching to second-line combination antiretroviral therapy (cART) are often observed in human immunodeficiency virus (HIV)-infected children of low-middle-income countries (LMIC).

METHODS

An observational study included HIV-infected children attending the Beira Central Hospital (Mozambique) and the Nsambya Hospital, Home Care Department (Uganda) evaluated clinical and immunological failure according to World Health Organization (WHO) 2006 guidelines. Baseline predictors for cART failure and for drug substitution were explored in unadjusted and adjusted Cox proportional hazard models.

RESULTS

Two hundred eighteen of 740 children with at least 24 weeks follow-up experienced treatment failure (29%; 95% confidence interval [CI] 26-33), with crude incidence of 20.0 events per 100 person-years (95% CI 17.5-22.9). Having tuberculosis co-infection or WHO stage 4, or starting a nontriple cART significantly increased risk of failure. Two hundred two of 769 (26.3%) children receiving cART substituted drug(s), with crude incidence of 15.4 events per 100 person-years (95% CI 13.4-17.7). Drug toxicity (18.3%), drug availability (17.3%), and tuberculosis drugs interaction (52, 25.7%) were main reported reasons, while only 9 (4%) patients switched cART for clinical or immunological failure. Children starting lamivudine-zidovudine-nevirapine or lamivudine-stavudine-efavirenz or lamivudine-zidovudine-efavirenz were more likely to have substitute drugs. Increased substitution was found in children with mild immunosuppression and tuberculosis co-infection at cART initiation as well as poor adherence before drug substitution.

CONCLUSIONS

Considerable delay in switching to second-line cART may occur despite an observed high rate of failure. Factors including WHO clinical stage and tuberculosis co-infection should be evaluated before starting cART. Toxicity and drug adherence should be monitored to minimize drug substitution in LMIC.

Why the proportion of transmission during early-stage HIV infection does not predict the long-term impact of treatment on HIV incidence

Antiretroviral therapy (ART) reduces the infectiousness of HIV-infected persons, but only after testing, linkage to care, and successful viral suppression. Thus, a large proportion of HIV transmission during a period of high infectiousness in the first few months after infection ("early transmission") is perceived as a threat to the impact of HIV "treatment-as-prevention" strategies. We created a mathematical model of a heterosexual HIV epidemic to investigate how the proportion of early transmission affects the impact of ART on reducing HIV incidence. The model includes stages of HIV infection, flexible sexual mixing, and changes in risk behavior over the epidemic. The model was calibrated to HIV prevalence data from South Africa using a Bayesian framework. Immediately after ART was introduced, more early transmission was associated with a smaller reduction in HIV incidence rate--consistent with the concern that a large amount of early transmission reduces the impact of treatment on incidence. However, the proportion of early transmission was not strongly related to the long-term reduction in incidence. This was because more early transmission resulted in a shorter generation time, in which case lower values for the basic reproductive number (R0) are consistent with observed epidemic growth, and R0 was negatively correlated with long-term intervention impact. The fraction of early transmission depends on biological factors, behavioral patterns, and epidemic stage and alone does not predict long-term intervention impacts. However, early transmission may be an important determinant in the outcome of short-term trials and evaluation of programs.

Evaluation of treatment outcomes for patients on first-line regimens in US President's Emergency Plan for AIDS Relief (PEPFAR) clinics in Uganda: predictors of virological and immunological response from RV288 analyses

OBJECTIVES

Viral load (VL) monitoring is recommended, but seldom performed, in resource-constrained countries. RV288 is a US President's Emergency Plan for AIDS Relief (PEPFAR) basic programme evaluation to determine the proportion of patients on treatment who are virologically suppressed and to identify predictors of virological suppression and recovery of CD4 cell count. Analyses from Uganda are presented here.

METHODS

In this cross-sectional, observational study, patients on first-line antiretroviral therapy (ART) (efavirenz or nevirapine+zidovudine/lamivudine) from Kayunga District Hospital and Kagulamira Health Center were randomly selected for a study visit that included determination of viral load (HIV-1 RNA), CD4 cell count and clinical chemistry tests. Subjects were recruited by time on treatment: 6-12, 13-24 or >24 months. Logistic regression modelling identified predictors of virological suppression. Linear regression modelling identified predictors of CD4 cell count recovery on ART.

RESULTS

We found that 85.2% of 325 subjects were virologically suppressed (viral load<47 HIV-1 RNA copies/ml). There was no difference in the proportion of virologically suppressed subjects by time on treatment, yet CD4 counts were higher in each successive stratum. Women had higher median CD4 counts than men overall (406 vs. 294 cells/μL, respectively; P<0.0001) and in each time-on-treatment stratum. In a multivariate logistic regression model, predictors of virological suppression included efavirenz use [odds ratio (OR) 0.47; 95% confidence interval (CI) 0.22-1.02; P=0.057], lower cost of clinic visits (OR 0.815; 95% CI 0.66-1.00; P=0.05), improvement in CD4 percentage (OR 1.06; 95% CI 1.014-1.107; P=0.009), and care at Kayunga vs. Kangulamira (OR 0.47; 95% CI 0.23-0.92; P=0.035). In a multivariate linear regression model of covariates associated with CD4 count recovery, time on highly active antiretroviral therapy (ART) (P<0.0001), patient satisfaction with care (P=0.038), improvements in total lymphocyte count (P<0.0001) and haemoglobin concentration (P=0.05) were positively associated, whereas age at start of ART (P=0.0045) was negatively associated with this outcome.

CONCLUSIONS

High virological suppression rates are achievable on first-line ART in Uganda. The odds of virological suppression were positively associated with efavirenz use and improvements in CD4 cell percentage and total lymphocyte count and negatively associated with the cost of travel to the clinic. CD4 cell reconstitution was positively associated with CD4 count at study visit, time on ART, satisfaction with care at clinic, haemoglobin concentration and total lymphocyte count and negatively associated with age.

Determinants of Mortality among Adult HIV-Infected Patients on Antiretroviral Therapy in a Rural Hospital in Southeastern Nigeria: A 5-Year Cohort Study

Background. Study examined the determinants of mortality among adult HIV patients in a rural, tertiary hospital in southeastern Nigeria, comparing mortality among various ART regimens. Methods. Retrospective cohort study of 1069 patients on ART between August 2008 and October 2013. Baseline CD4 counts, age, gender, and ART regimen were considered in this study. Kaplan-Meier method was used to estimate survival and Cox proportional hazards models to identify multivariate predictors of mortality. Median follow-up period was 24 months (IQR 6–45). Results. 78 (7.3%) patients died with 15.6% lost to followup. Significant independent predictors of mortality include age (>45), sex (male > female), baseline CD4 stage (<200), and ART combination. Adjusted mortality hazard was 3 times higher among patients with CD4 count <200 cells/μL than those with counts >500 (95% CI 1.69–13.59). Patients on Truvada-based first-line regimens were 88% more likely to die than those on Combivir-based first line (95% CI 1.05–3.36), especially those with CD4 count <200 cells/μL. Conclusion. Study showed lower mortality than most studies in Nigeria and Africa, with mortality higher among males and patients with CD4 count <200. Further studies are recommended to further compare treatment outcomes between Combivir- and Truvada-based regimens in resource-limited settings using clinical indicators.

Modeling the cost-effectiveness of HIV treatment: how to buy the most 'health' when resources are limited

PURPOSE OF REVIEW

To summarize recent cost-effectiveness analyses (CEAs) that evaluate optimal treatment strategies for persons living with HIV/AIDS (PLWHA).

RECENT FINDINGS

Efforts to attain universal coverage of current treatment guidelines (e.g., initiation at CD4 cell count <350 cells/μl) are generally very costeffective. Expansion of access beyond current guidelines will additionally improve clinical outcomes and aversion of new HIV infections; however, cost-effectiveness is more uncertain. Increasing access to antiretroviral therapy (ART) offers greater health benefit than investing the same funds in intensive laboratory monitoring for those on ART, particularly in those settings in which universal coverage has not yet been attained. Recommended ART regimens (e.g., tenofovir) have favorable cost-effectiveness when compared with substitution of newer, more expensive agents (e.g., rilpivirine, darunavir) or substitution of older, cheaper alternatives that are more toxic (e.g., stavudine).

SUMMARY

There is increasing use of CEA to evaluate decisions regarding HIV treatment in order to buy the most 'health' with limited resources. Expansion of ART access provides substantial clinical and preventive benefit and offers favorable cost-effectiveness. Intensive laboratory monitoring may not be the highest priority in settings in which resources are constrained. Further work on the economic impact, clinical effectiveness, and feasibility of ART treatment for all (e.g., no CD4 cell initiation criteria) is needed.

Future of phylogeny in HIV prevention

The success of the HIV Prevention Trials Network 052 trial has led to revisions in HIV-1 treatment guidelines. Antiretroviral therapy may reduce the risk of HIV-1 transmissions at the population level. The design of successful treatment as prevention interventions will be predicated on a comprehensive understanding of the spatial, temporal, and biological dynamics of heterosexual men who have sex with men and intravenous drug user epidemics. Viral phylogenetics can capture the underlying structure of transmission networks based on the genetic interrelatedness of viral sequences and cluster networks that could not be otherwise identified. This article describes the phylogenetic expansion of the Montreal men who have sex with men epidemic over the last decade. High rates of coclustering of primary infections are associated with 1 infection leading to 13 onward transmissions. Phylogeny substantiates the role of primary and recent stage infection in transmission dynamics, underlying the importance of timely diagnosis and immediate antiretroviral therapy initiation to avert transmission cascades.

Rates of switching antiretroviral drugs in a primary care service in South Africa before and after introduction of tenofovir

Introduction

Antiretroviral changes (single drug substitutions and regimen switches) limit treatment options and introduce challenges such as increased cost, monitoring and adherence difficulties. Patterns of drug substitutions and regimen switches from stavudine (d4T) and zidovudine (AZT) regimens have been well described but data on tenofovir (TDF) are more limited. This study describes the patterns and risk factors for drug changes of these antiretroviral drugs in adults.

Method

This retrospective cohort study included HIV positive, antiretroviral treatment (ART) naïve adults aged ≥18 years who started ART with two nucleoside reverse transcriptase inhibitors (NRTIs) and a non-nucleoside reverse transcriptase inhibitor. Follow-up was censored at first drug change and analysis focused on NRTI changes only.

Results

Between September 2002 and April 2011, 5095 adults initiated ART in Gugulethu. This comprised 948 subjects on TDF, 3438 on d4T and 709 subjects on AZT. Virological suppression rates at 1 year, regimen switching due to virological failure and overall losses to the programme were similar across the three groups. TDF had the lowest incidence rate of drug substitutions (2.6 per 100 P/Ys) compared to 17.9 for d4T and 8.5 per 100 P/Ys for AZT. Adverse drug reactions (ADRs) accounted for the majority of drug substitutions of d4T. Multivariate analysis showed that increasing age, female sex and d4T exposure were associated with increased hazard of drug substitution due to ADRs. Conversely, TDF exposure was associated with a substantially lower risk of substitution (adjusted hazards ratio 0.38; 95% CI 0.20–0.72).

Conclusion

Regimen switches and virological suppression were similar for patients exposed to TDF, d4T and AZT, suggesting all regimens were equally effective. However, TDF was better tolerated with a substantially lower rate of drug substitutions due to ADRs.

Pharmacological and clinical evidence of nevirapine immediate- and extended-release formulations

We reviewed the current information available on nevirapine immediate- and extended-release formulations and its role in single-dose and combination antiretroviral therapy. Nevirapine was approved in 1996 and was the first non-nucleoside reverse-transcriptase inhibitor available for the treatment of HIV-1 infection. Nevirapine has demonstrated good efficacy and a well-characterized safety profile. A major drawback is the low genetic barrier, allowing the emergence of resistance in the presence of single mutations in the reverse-transcriptase gene. This shortcoming is particularly relevant when nevirapine is administered in a single dose to prevent mother-to-child transmission of HIV-1 infection, compromising the efficacy of future non-nucleoside reverse transcriptase-inhibitor regimens. Studies published recently have probed the noninferiority of nevirapine compared to ritonavir-boosted atazanavir with both tenofovir disoproxil fumarate and emtricitabine in antiretroviral treatment-naïve patients. In 2011, a new formulation of nevirapine (nevirapine extended release) that allowed once-daily dosing was approved by the Food and Drug Administration and by the European Medicines Agency. VERxVe, a study comparing nevirapine extended release with nevirapine immediate release in antiretroviral treatment-naïve patients, and TRANxITION, a study carried out in antiretroviral treatment-experienced patients who switched therapy from nevirapine immediate release to nevirapine extended release, provided data on the noninferiority of the new formulation of nevirapine compared with nevirapine immediate release in terms of efficacy and safety. Nevirapine extended release will further increase the durability and persistence of nevirapine-containing antiretroviral therapy, allowing once-daily dosing regimens.

HIV in Africa: Challenges and Directions for the Next Decade

Africa carries a disproportionate burden of the global HIV endemic, accounting for two thirds of the global 33.3 million people living with HIV. While tremendous advances have been made in addressing the HIV epidemic in Africa, considerable challenges remain. Testing for HIV increased by 86% from 2007 to 2009 but more than 75% of people 15-49 years remain unaware of their HIV status. CD4 count at diagnosis tends to be low and linkage to care and treatment is suboptimal. The scale-up of antiretroviral therapy is ongoing but is hampered by the lack of diagnostic capability to monitor response to therapy and a substantial healthcare workforce shortage. Prevention strategies such as male circumcision, pre-exposure prophylaxis, and antiretroviral therapy for prevention have generated great excitement but cost and healthcare infrastructure deficiencies may limit their widespread applicability. Operational research to validate and inform treatment decisions, health care policies, and prevention strategies is sorely needed.

HIV treatment and care in resource-constrained environments: challenges for the next decade

Many successes have been achieved in HIV care in low- and middle-income countries (LMIC): increased number of HIV-infected individuals receiving antiretroviral treatment (ART), wide decentralization, reduction in morbidity and mortality and accessibility to cheapest drugs. However, these successes should not hide existing failures and difficulties. In this paper, we underline several key challenges. First, ensure long-term financing, increase available resources, in order to meet the increasing needs, and redistribute the overall budget in a concerted way amongst donors. Second, increase ART coverage and treat the many eligible patients who have not yet started ART. Competition amongst countries is expected to become a strong driving force in encouraging the least efficient to join better performing countries. Third, decrease early mortality on ART, by improving access to prevention, case-finding and treatment of tuberculosis and invasive bacterial diseases and by getting people to start ART much earlier. Fourth, move on from WHO 2006 to WHO 2010 guidelines. Raising the cut-off point for starting ART to 350 CD4/mm³ needs changing paradigm, adopting opt-out approach, facilitating pro-active testing, facilitating task shifting and increasing staff recruitments. Phasing out stavudine needs acting for a drastic reduction in the costs of other drugs. Scaling up routine viral load needs a mobilization for lower prices of reagents and equipments, as well as efforts in relation to point-of-care automation and to maintenance. The latter is a key step to boost the utilization of second-line regimens, which are currently dramatically under prescribed. Finally, other challenges are to reduce lost-to-follow-up rates; manage lifelong treatment and care for long-term morbidity, including drug toxicity, residual AIDS and HIV-non-AIDS morbidity and aging-related morbidity; and be able to face unforeseen events such as socio-political and military crisis. An old African proverb states that the growth of a deep-rooted tree cannot be stopped. Our tree is well rooted in existing field experience and is, therefore, expected to grow. In order for us to let it grow, long-term cost-effectiveness approach and life-saving evidence-based programming should replace short-term budgeting approach.

Cost-effectiveness of tenofovir instead of zidovudine for use in first-line antiretroviral therapy in settings without virological monitoring

Background

The most recent World Health Organization (WHO) antiretroviral treatment guidelines recommend the inclusion of zidovudine (ZDV) or tenofovir (TDF) in first-line therapy. We conducted a cost-effectiveness analysis with emphasis on emerging patterns of drug resistance upon treatment failure and their impact on second-line therapy.

Methods

We used a stochastic simulation of a generalized HIV-1 epidemic in sub-Saharan Africa to compare two strategies for first-line combination antiretroviral treatment including lamivudine, nevirapine and either ZDV or TDF. Model input parameters were derived from literature and, for the simulation of resistance pathways, estimated from drug resistance data obtained after first-line treatment failure in settings without virological monitoring. Treatment failure and cost effectiveness were determined based on WHO definitions. Two scenarios with optimistic (no emergence; base) and pessimistic (extensive emergence) assumptions regarding occurrence of multidrug resistance patterns were tested.

Results

In the base scenario, cumulative proportions of treatment failure according to WHO criteria were higher among first-line ZDV users (median after six years 36% [95% simulation interval 32%; 39%]) compared with first-line TDF users (31% [29%; 33%]). Consequently, a higher proportion initiated second-line therapy (including lamivudine, boosted protease inhibitors and either ZDV or TDF) in the first-line ZDV user group 34% [31%; 37%] relative to first-line TDF users (30% [27%; 32%]). At the time of second-line initiation, a higher proportion (16%) of first-line ZDV users harboured TDF-resistant HIV compared with ZDV-resistant viruses among first-line TDF users (0% and 6% in base and pessimistic scenarios, respectively). In the base scenario, the incremental cost effectiveness ratio with respect to quality adjusted life years (QALY) was US$83 when TDF instead of ZDV was used in first-line therapy (pessimistic scenario: US$ 315), which was below the WHO threshold for high cost effectiveness (US$ 2154).

Conclusions

Using TDF instead of ZDV in first-line treatment in resource-limited settings is very cost-effective and likely to better preserve future treatment options in absence of virological monitoring.

Stavudine toxicity in adult longer-term ART patients in Blantyre, Malawi

BACKGROUND

Stavudine is an effective and inexpensive antiretroviral drug, but no longer recommended by WHO for first-line antiretroviral regimens in resource-limited settings due to toxicity concerns. Because of the high cost of alternative drugs, it has not been feasible to replace stavudine in most adults in the Malawi ART programme. We aimed to provide policy makers with a detailed picture of stavudine toxicities in Malawians on longer-term ART, in order to facilitate prioritization of stavudine replacement among other measures to improve the quality of ART programmes.

METHODS

Prospective cohort of Malawian adults who had just completed one year of stavudine containing ART in an urban clinic, studying peripheral neuropathy, lipodystrophy, diabetes mellitus, high lactate syndromes, pancreatitis and dyslipidemia during 12 months follow up. Stavudine dosage was 30 mg irrespective of weight. Cox regression was used to determine associations with incident toxicities.

RESULTS

253 patients were enrolled, median age 36 years, 62.5% females. Prevalence rates (95%-confidence interval) of toxicities after one year on stavudine were: peripheral neuropathy 21.3% (16.5-26.9), lipodystrophy 14.7% (2.4-8.1), high lactate syndromes 0.0% (0-1.4), diabetes mellitus 0.8% (0-2.8), pancreatitis 0.0% (0-1.5). Incidence rates per 100 person-years (95%-confidence interval) during the second year on stavudine were: peripheral neuropathy 19.8 (14.3-26.6), lipodystrophy 11.4 (7.5-16.3), high lactate syndromes 2.1 (0.7-4.9), diabetes mellitus 0.4 (0.0-1.4), pancreatitis 0.0 (0.0-0.2). Prevalence of hypercholesterolemia and hypertriglyceridemia increased from 12.1% to 21.1% and from 29.5% to 37.6% respectively between 12 and 24 months. 5.5% stopped stavudine, 1.3% died and 4.0% defaulted during follow up. Higher age was an independent risk factor for incident peripheral neuropathy and lipodystrophy.

CONCLUSION

Stavudine associated toxicities continued to accumulate during the second year of ART, especially peripheral neuropathy and lipodystrophy and more so at increasing age. Our findings support investments for replacing stavudine in first-line regimens in sub-Saharan Africa.

Genotype assays and third-line ART in resource-limited settings: a simulation and cost-effectiveness analysis of a planned clinical trial

OBJECTIVES

To project the clinical and economic outcomes of a genotype assay for selection of third-line antiretroviral therapy (ART) in resource-limited settings, as per the planned international A5288 trial (MULTI-OCTAVE).

METHODS

We used the Cost-effectiveness of Preventing AIDS Complications (CEPAC)-International Model to compare three strategies for patients who have failed second-line ART in South Africa: sustained second-line: no genotype assay, all patients remain on second-line ART; A5288: genotype to determine the resistance profile and assign an appropriate regimen; or population-based third-line: no genotype, all patients switch to a potent third-line regimen. Model inputs are from published data in South Africa. Resistance profiles, ART regimens, and efficacy data were those used for trial planning.

RESULTS

Projected life expectancy for sustained second-line, A5288, and population-based third-line are 61.1, 103.8, and 104.2 months. Compared to sustained second-line ($12 ,460), per person lifetime costs increase for the A5288 ($39, 250) and population-based ($44, 120) strategies. The incremental cost-effectiveness ratio of A5288, compared to sustained second-line, is $7500/year of life saved (YLS), and for population-based third-line, compared to A5288, is $154 ,500/YLS. In the A5288 strategy, very late presentation to care, coupled with lengthy delays to obtain the genotype, dramatically reduces 5-year survival, making the population-based third-line strategy more attractive.

CONCLUSIONS

We project that, whereas the public health approach to third-line therapy is unaffordable, genotype assays and third-line ART in resource-limited settings will increase survival and be cost-effective compared to the population-based approach, supporting the value of an efficacy study.

The macroeconomic consequences of renouncing to universal access to antiretroviral treatment for HIV in Africa: a micro-simulation model

AIM

Previous economic literature on the cost-effectiveness of antiretroviral treatment (ART) programs has been mainly focused on the microeconomic consequences of alternative use of resources devoted to the fight against the HIV pandemic. We rather aim at forecasting the consequences of alternative scenarios for the macroeconomic performance of countries.

METHODS

We used a micro-simulation model based on individuals aged 15-49 selected from nationally representative surveys (DHS for Cameroon, Tanzania and Swaziland) to compare alternative scenarios : 1-freezing of ART programs to current levels of access, 2- universal access (scaling up to 100% coverage by 2015, with two variants defining ART eligibility according to previous or current WHO guidelines). We introduced an "artificial" ageing process by programming methods. Individuals could evolve through different health states: HIV negative, HIV positive (with different stages of the syndrome). Scenarios of ART procurement determine this dynamics. The macroeconomic impact is obtained using sample weights that take into account the resulting age-structure of the population in each scenario and modeling of the consequences on total growth of the economy.

RESULTS

Increased levels of ART coverage result in decreasing HIV incidence and related mortality. Universal access to ART has a positive impact on workers' productivity; the evaluations performed for Swaziland and Cameroon show that universal access would imply net cost-savings at the scale of the society, when the full macroeconomic consequences are introduced in the calculations. In Tanzania, ART access programs imply a net cost for the economy, but 70% of costs are covered by GDP gains at the 2034 horizon, even in the extended coverage option promoted by WHO guidelines initiating ART at levels of 350 cc/mm(3) CD4 cell counts.

CONCLUSION

Universal Access ART scaling-up strategies, which are more costly in the short term, remain the best economic choice in the long term. Renouncing or significantly delaying the achievement of this goal, due to "legitimate" short term budgetary constraints would be a misguided choice.

HIV treatment as prevention: modelling the cost of antiretroviral treatment--state of the art and future directions

Policy discussions about the feasibility of massively scaling up antiretroviral therapy (ART) to reduce HIV transmission and incidence hinge on accurately projecting the cost of such scale-up in comparison to the benefits from reduced HIV incidence and mortality. We review the available literature on modelled estimates of the cost of providing ART to different populations around the world, and suggest alternative methods of characterising cost when modelling several decades into the future. In past economic analyses of ART provision, costs were often assumed to vary by disease stage and treatment regimen, but for treatment as prevention, in particular, most analyses assume a uniform cost per patient. This approach disregards variables that can affect unit cost, such as differences in factor prices (i.e., the prices of supplies and services) and the scale and scope of operations (i.e., the sizes and types of facilities providing ART). We discuss several of these variables, and then present a worked example of a flexible cost function used to determine the effect of scale on the cost of a proposed scale-up of treatment as prevention in South Africa. Adjusting previously estimated costs of universal testing and treatment in South Africa for diseconomies of small scale, i.e., more patients being treated in smaller facilities, adds 42% to the expected future cost of the intervention.