Drug Therapy Improves Short-Term Survival of AIDS Patients

Marc Kusinitz
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School of Public Health

     The widespread availability of drugs to treat AIDS has
significantly improved the survival rate of those who are HIV
positive, but the ability of those drugs to extend life is
limited, according to a study by researchers at the Johns Hopkins
School of Public Health and School of Medicine. 

     The results were published in the May 1 issue of Journal of
the American Medical Association. By studying the differences
between groups of HIV positive men in two distinctly different
time periods, the researchers were also able to devise a way to
estimate expected survival time according to both CD4 cell counts
and the presence or absence of clinical symptoms. 

     The CD4 cell is a protein on the surface of T-cells, which
orchestrate the immune system's response to certain foreign
invaders. The AIDS virus latches onto CD4 cells, reducing their
numbers and, thereby, knocking out their ability to respond to
these bacterial or viral attacks.

     "This is the first study to measure the impact of HIV
therapy on survival at the population level," said lead author
Cheryl Enger, assistant professor at the Oncology Center.

     Researchers looked at a group of HIV-1 infected men from
July 1985 through July 1993. During the years 1985 through 1988,
therapy was not widely available. From 1989 through 1993, a
substantial number of those studied were using antiretroviral
drugs and other preventive measures. Different stages of disease
progression were defined by both CD4 level and by the presence or
absence of clinical symptoms. 

     For asymptomatic HIV-1 infected men with CD4 counts less
than 100, the two-and-a-half-year survival rate increased from 22 
percent in the first time period to 54 percent in the second time
period. In the same time period, the survival rate for those with
CD4 counts in the 101 to 200 range rose from 53 percent to 71
percent. In the range of 201 to 300 CD4 cells, the percent
surviving at the two-and-a-half-year mark increased from 83
percent to 91 percent.

     Although the percent surviving doubled for those with fewer
than 200 CD4 cells, the average increase in survival time ranged
from eight to 14 months, depending on the starting CD4 count.
"This improvement in survival was modest, but encouraging," said
Neil Graham, associate professor of epidemiology at the schools
of Public Health and Medicine. "With the newer, more powerful
drugs now available, I expect we will do even better."

     The study, funded by the National Institute of Allergy and
Infectious Diseases, National Institutes of Health, also
indicated that those with identical CD4 levels differed in their
survival rates depending on whether or not they evidenced
clinical symptoms such as thrush or high fever. This held true
even for individuals with relatively high CD4 levels. These
findings confirmed earlier studies showing that those with
clinical symptoms, even though their infection had not progressed
to AIDS, still had a greater risk of dying than those without
symptoms. 

     The public policy implications of these findings are the
support and affirmation they present for the guidelines issued by
the National Public Health Service. The guidelines recommend that
individuals with clinical symptoms, regardless of their CD4
count, should receive treatment immediately. 

     "What we saw," said Alvaro Munoz, a professor of
epidemiology at the School of Public Health, "was that men who
had identical CD4 levels were surviving longer in the calendar
period with wide use of antiretroviral therapy. In the short
term, the drugs are working. In the long term, the virus
dominates."