Drug Therapy Improves Short-Term Survival of AIDS Patients Marc Kusinitz ----------------------------- 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."
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