Article

Cost-effectiveness of HIV Monitoring Strategies in Resource-Limited Settings

Center for Health Policy and the Center for Primary Care and Outcomes Research, School of Medicine, Stanford University, 117 Encina Commons, Stanford, CA 94305, USA.
Archives of internal medicine (Impact Factor: 17.33). 10/2008; 168(17):1910-8. DOI: 10.1001/archinternmed.2008.1
Source: PubMed

ABSTRACT

Although the number of infected persons receiving highly active antiretroviral therapy (HAART) in low- and middle-income countries has increased dramatically, optimal disease management is not well defined.
We developed a model to compare the costs and benefits of 3 types of human immunodeficiency virus monitoring strategies: symptom-based strategies, CD4-based strategies, and CD4 counts plus viral load strategies for starting, switching, and stopping HAART. We used clinical and cost data from southern Africa and performed a cost-effectiveness analysis. All assumptions were tested in sensitivity analyses.
Compared with the symptom-based approaches, monitoring CD4 counts every 6 months and starting treatment at a threshold of 200/muL was associated with a gain in life expectancy of 6.5 months (61.9 months vs 68.4 months) and a discounted lifetime cost savings of US $464 per person (US $4069 vs US $3605, discounted 2007 dollars). The CD4-based strategies in which treatment was started at the higher threshold of 350/microL provided an additional gain in life expectancy of 5.3 months at a cost-effectiveness of US $107 per life-year gained compared with a threshold of 200/microL. Monitoring viral load with CD4 was more expensive than monitoring CD4 counts alone, added 2.0 months of life, and had an incremental cost-effectiveness ratio of US $5414 per life-year gained relative to monitoring of CD4 counts. In sensitivity analyses, the cost savings from CD4 count monitoring compared with the symptom-based approaches was sensitive to cost of inpatient care, and the cost-effectiveness of viral load monitoring was influenced by the per test costs and rates of virologic failure.
Use of CD4 monitoring and early initiation of HAART in southern Africa provides large health benefits relative to symptom-based approaches for HAART management. In southern African countries with relatively high costs of hospitalization, CD4 monitoring would likely reduce total health care expenditures. The cost-effectiveness of viral load monitoring depends on test prices and rates of virologic failure.

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    • "Randomized trials did not show survival benefits associated with viral load monitoring in these settings, although their follow-up time was very limited, at <3 years [21]. Model-based evaluations have yielded conflicting results about the cost-effectiveness of survival gains [22, 23]. However, the importance of virologic monitoring is increasingly being recognized. "
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    ABSTRACT: Antiretroviral treatment (ART) is expanding to human immunodeficiency virus type 1 (HIV-1)-infected persons in low-middle income countries, thanks to a public health approach. With 3 available drug classes, 2 ART sequencing lines are programmatically foreseen. The emergence and transmission of viral drug resistance represents a challenge to the efficacy of ART. Knowledge of HIV-1 drug resistance selection associated with specific drugs and regimens and the consequent activity of residual drug options are essential in programming ART sequencing options aimed at preserving ART efficacy for as long as possible. This article determines optimal ART sequencing options for overcoming HIV-1 drug resistance in resource-limited settings, using currently available drugs and treatment monitoring opportunities. From the perspective of drug resistance and on the basis of limited virologic monitoring data, optimal sequencing seems to involve use of a tenofovir-containing nonnucleoside reverse-transcriptase inhibitor-based first-line regimen, followed by a zidovudine-containing, protease inhibitor (PI)-based second-line regimen. Other options and their consequences are explored by considering within-class and between-class sequencing opportunities, including boosted PI monotherapies and future options with integrase inhibitors. Nucleoside reverse-transcriptase inhibitor resistance pathways in HIV-1 subtype C suggest an additional reason for accelerating stavudine phase out. Viral load monitoring avoids the accumulation of resistance mutations that significantly reduce the activity of next-line options. Rational use of resources, including broader access to viral load monitoring, will help ensure 3 lines of fully active treatment options, thereby increasing the duration of ART success.
    Preview · Article · Jun 2013 · The Journal of Infectious Diseases
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    • "Our Markov model included several significant improvements on previously published models [4], [18]–[22]. First, we separated out the first six months on ART, as outcomes and costs in this period are driven by baseline CD4 count and program protocols (higher frequency of clinic visits and toxicity monitoring) [6]. Second, we developed a novel LTFU model, in which patients transitioned between ART and LTFU, changed baseline CD4 count within LTFU, and transitioned to death within LTFU. "
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    ABSTRACT: Providing private antiretroviral therapy (ART) care for public sector patients could increase access to ART in low- and middle-income countries. We compared the costs and outcomes of a private-care and a public-care ART program in South Africa. A novel Markov model was developed from the public-care program. Patients were first tunneled for 6 months in their baseline CD4 category before being distributed into a dynamic CD4 and viral load model. Patients were allowed to return to ART care from loss to follow up (LTFU). We then populated this modeling framework with estimates derived from the private-care program to externally validate the model. Baseline characteristics were similar in the two programs. Clinic visit utilization was higher and death rates were lower in the first few years on ART in the public-care program. After 10 years on ART we estimated the following outcomes in the public-care and private-care programs respectively: viral load <1000 copies/ml 89% and 84%, CD4 >500 cells/μl 33% and 37%, LTFU 14% and 14%, and death 27% and 32%. Lifetime undiscounted survival estimates were 14.1 (95%CI 13.2-14.9) and (95%CI 12.7-14.5) years with costs of 18,734 (95%CI 12,588-14,022) and 13,062 (95%CI 12,077-14,047) USD in the private-care and public-care programs respectively. When clinic visit utilization in the public-care program was reduced by two thirds after the initial 6 months on ART, which is similar to their current practice, the costs were comparable between the programs. Using a novel Markov model, we determined that the private-care program had similar outcomes but lower costs than the public-care program, largely due to lower visit frequencies. These findings have important implications for increasing and sustaining coverage of patients in need of ART care in resource-limited settings.
    Full-text · Article · Feb 2013 · PLoS ONE
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    • "c The sensitivity range is not reported in [23]. In our model, we assume a 50% decrease and 50% increase in OI’s relative to the base case. "
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    ABSTRACT: Background Ugandan national guidelines recommend initiation of combination antiretroviral therapy (cART) at CD4+ T cell (CD4) count below 350 cell/μl, but the implementation of this is limited due to availability of medication. However, cART initiation at higher CD4 count increases survival, albeit at higher lifetime treatment cost. This analysis evaluates the cost-effectiveness of initiating cART at a CD4 count between 250–350 cell/μl (early) versus <250 cell/μl (delayed). Methods Life expectancy of cART-treated patients, conditional on baseline CD4 count, was modeled based on published literature. First-line cART costs $192 annually, with an additional $113 for patient monitoring. Delaying initiation of cART until the CD4 count falls below 250 cells/μl would incur the cost of the bi-annual CD4 count tests and routine maintenance care at $85 annually. We compared lifetime treatment costs and disability adjusted life-expectancy between early vs. delayed cART for ten baseline CD4 count ranges from 250-350 cell/μl. All costs and benefits were discounted at 3% annually. Results Treatment delay varied from 6–18 months. Early cART initiation increased life expectancy from 1.5-3.5 years and averted 1.33–3.10 disability adjusted life years (DALY’s) per patient. Lifetime treatment costs were $4,300–$5,248 for early initiation and $3,940–$4,435 for delayed initiation. The cost/DALY averted of the early versus delayed start ranged from $260–$270. Conclusions In HIV-positive patients presenting with CD4 count between 250-350 cells/μl, immediate initiation of cART is a highly cost-effective strategy using the recommended one-time per capita GDP threshold of $490 reported for Uganda. This would constitute an efficient use of scarce health care funds.
    Full-text · Article · Sep 2012 · BMC Public Health
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