In a nutshell
- Problem: HIV/AIDS is one of the leading causes of adult deaths in the developing world.
- Program: Antioretroviral therapy (ART) is a treatment for HIV/AIDS that can prolong and improve patients' lives, and potentially reduce the risk that they will infect others.
- Track record: ART does effectively prolong life. However, it is not entirely clear (a) for how long it can prolong life, (b) what the long-term side effects of treatment may be, and (c) how different types of individuals respond (e.g., effectiveness for drug users versus others).
- Cost-effectiveness: ART is estimated to cost over $100 per year of treatment provided. We previously concluded that this made ART substantially less cost-effective than many other global health interventions, but we plan to revisit this conclusion in light of falling confidence in other cost-effectiveness estimates.
Basics of the program
What is the program? What problem does it target?
Anti-retroviral therapy (ART) is a treatment for HIV/AIDS. It does not cure the disease; rather, it aims to increase life expectancy, reduce opportunistic infections, and may potentially reduce the likelihood that an infected individual transmits the virus to another. (More on HIV/AIDS
What are the components required to implement this program - how does it work?
A successful ART program requires all of the following:
- Diagnosis. A means for testing individuals to identify those in need of treatment. In the case of ART, diagnosis consists of more than merely testing an individual for HIV/AIDS. This is because when the disease is far enough along, the toxicity of the drugs may outweigh the benefits of starting treatment.
- Distribution. A method for distributing the drugs to those who need them.
- Drugs. Antiretroviral drugs can be costly. (For more, see our cost-effectiveness section below.)
- Patient adherence to drug regimen. ART consists of a relatively complex drug regimen to which patients must strictly adhere. And because ART does not cure HIV/AIDS, patients must adhere to the regimen as long as they remain alive.
- Monitoring of the patient's response to treatment. ART may cause negative side effects in a patient. In addition, laboratory monitoring may be needed for purposes of noticing decreased efficacy or the development of resistance.
Program track record
Micro evidence: Has this program been rigorously evaluated and shown to work?
A review by the Cochrane Collaboration
states, "Combination antiretroviral therapy administered to HIV-infected individuals has been shown to decrease viral replication, improve immunologic function and delay the progression of HIV infection."
People on ART do not appear to have fully normal lifespans. A recent review of 14 studies following patients who had received ART in high-income countries
as far back as 1996 found that those on treatment lost 247 "potential person-years of life" (years of life between the ages of 20 and 64) per 1,000 person-years. These figures vary significantly based on a patient's background characteristics. For example, injecting drug users receiving ART lost 506 "potential person-years of life" per 1,000 person-years.
Evidence also suggests (though not highly rigorously) that ART can also reduce the chances that a patient transmits the virus to others.
Macro evidence: Has this program played a role in large-scale success stories?
The Disease Control Priorities Report states that "because antiretroviral therapy has historically been unavailable in most developing countries, national programs have lacked the means to undertake a comprehensive approach to HIV/AIDS (notable exceptions are Argentina, Brazil, and Mexico, which provide universal coverage for antiretroviral therapy)." We also have seen references to Botswana as an example of successfully implementation of mass coverage of ART.
What are the potential downsides of the intervention?
ART can harm patients by causing complications from latent or undiagnosed opportunistic infections, causing direct side effects, or by causing other illnesses over the long term due to the drugs' toxicity.
The cost-effectiveness of providing a patient with ART depends on:
- A patient's adherence to the regimen. A patient must adhere closely to the drug regimen or it can quickly become ineffective. (For more, see our discussion of drug adherence, above.) In practice, it appears that patient adherence can vary significantly.
- The cost of drugs. The cost of drugs has changed significantly since the introduction of ART.
The most recent estimate we've found of drug costs comes from The Global Fund to Fight Aids, Tuberculosis and Malaria, which reports median expenditures on drugs of $188 per person per year of first-line ART drugs, and $588 per person per year for all ART program costs across its large, broad global project portfolio. We have also examined data from the William J. Clinton Foundation's HIV/AIDS Initiative (CHAI), which provides drug procurement services for some of the ART drugs purchased by more than 70 countries. In 2007, according to this data, the cost of a year's worth of ART was $299 for first-line drugs and $709 for second-line drugs.
- The effectiveness of the drugs. Based on a review of 14 studies of long-term patients on ART (discussed above), we believe that a year's worth of ART saves .50-.75 years of life.
The Disease Control Priorities Report
estimates that ART costs $350-$1,494 per disability-adjusted life-year (DALY) averted in Sub-Saharan Africa. This is equivalent (from a simple conversion calculation) to $129.50-$552.78 per year spent on ART, which seems roughly consistent with the drug price estimates given directly above. (More on the DALY metric
We previously concluded that this made ART substantially less cost-effective than many other global health interventions, but we plan to revisit this conclusion in light of falling confidence in other cost-effectiveness estimates