Researchers from the Johns Hopkins Bloomberg School of
Public Health, Centers for Disease Control and Prevention
and the Chiang Mai University in Thailand evaluated the
ability of inexpensive biological markers, which are
obtainable in resource-poor countries, to determine which
HIV-infected patients are in the greatest need of
antiretroviral therapy. Cheaper diagnostic methods and
knowledge of disease progression can be useful for public
health practitioners trying to treat HIV patients. The
study is published in the June issue of the
International Journal of Epidemiology.
"One of the major concerns for health care workers in
many developing countries is deciding which of the many
HIV-infected patients in their clinic needs treatment the
most. Use of these less expensive markers can be helpful in
guiding this treatment decision," said Kenrad E. Nelson,
corresponding author of the study and a professor in the
Bloomberg School's
Department of Epidemiology.
Nelson explained that doctors in the United States
typically measure the CD4-lymphocyte count and HIV-viral
load to decide when to start treatment of an HIV-infected
patient; the count requires an expensive instrument and
trained laboratory staff and is expensive to perform. The
World Health Organization has recommended that clinics in
Africa and Asia that lack modern laboratory facilities may
assume that a total lymphocyte count of 1,200 cells/ml or
less indicates that a patient's CD4-lymphocyte count is
below 200 cells/ml and that the patient therefore needs
treatment.
The research group from Johns Hopkins studied 836
HIV-infected patients from Thailand enrolled in the study
between 1992 and 1997. They found that nearly all patients
whose total lymphocyte counts were below 1,200 cells/ml had
fewer than 200 CD4 lymphocytes per ml; more importantly,
however, the scientists found that this WHO-recommended
marker failed to detect about two-thirds of the patients
with low CD4 lymphocyte counts.
The researchers therefore evaluated additional markers
that would be readily available in a resource-poor setting
to see if the ability to predict 200 or fewer
CD4-lymphocytes, and thus the need for treatment, could be
improved. Combining the total lymphocyte count with the
presence of anemia and a low body-mass index substantially
increased the accuracy of predicting who needed
antiretroviral therapy in the study population in northern
Thailand.
In this Thai population, the median survival time from
HIV infection to death was 7.8 years, significantly shorter
than has been reported for HIV-infected populations in the
United States and Europe. Even so, the markers evaluated,
as well as the CD4 cell count, were able to reliably
predict those with a poor chance of survival in this
population.
The WHO and many other groups are making a major
effort now to provide effective antiretroviral therapy to
several million HIV-infected people living in developing
countries in Africa, Asia and elsewhere. The WHO also has a
program that aims to treat 3 million people for AIDS in
Africa and Asia by the end of 2005. To reach this ambitious
goal, inexpensive and available markers must be evaluated
so they can be used in resource-limited clinics to select
those most in need of therapy.
The study was supported by a grant provided by the
Contraceptive Research and Development Program at Eastern
Virginia Medical School, which is affiliated with USAID.
USAID receives funds from the Division of Reproductive
Health at the Centers for Disease Control and
Prevention.
GO TO