Under current treatment guidelines, highly active antiretroviral therapy (HAART) should be considered for HIV-infected patients when their CD4+ T-cell counts fall below 350 cells per cubic millimeter (mm3).
However, new epidemiological research suggests that patients with HIV may have less risk of dying if they begin HAART sooner.
HIV ravages CD4+ T-cells, one of the human immune system’s primary weapons for fighting off infection. As virus levels increase in the blood, HIV-infected patients experience a decrease in CD4+ T-cells and declining health. HAART–a combination of at least three HIV medicines–is used to reduce virus levels.
Although current treatment guidelines recommend that patients begin HAART once their CD4+ T-cell counts fall below the 350 cells/mm3 threshold, the optimal time to begin therapy has been unclear because of insufficient clinical trial data. U.S. and Canadian researchers, working through the International Epidemiology Databases to Evaluate AIDS (IeDEA), set out to take steps towards establishing a clinical basis for initiating treatment. IeDEA, a global network of clinics that serve HIV patients and collect data important to key HIV/AIDS research questions, was initiated by and is funded in part by the National Institute of Allergy and Infectious Diseases (NIAID), a component of the National Institutes of Health (NIH). IeDEA is co-funded by the National Cancer Institute and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
From 1996 to 2006, the research team examined 8,374 HIV-infected study participants with CD4+ T-cell counts of 351-500 cells/mm3 who had never taken antiretroviral treatment and were free of AIDS-related illnesses. Thirty percent (2,473) of the study participants began taking HAART, while the remaining 70 percent (5,901) of participants deferred treatment until their CD4+ T-cell counts fell below 350 cells/mm3. The researchers found a 71 percent higher risk of death for patients who deferred treatment rather than initiating HAART, suggesting that therapy should begin at an earlier stage of HIV disease than currently recommended. A randomized clinical trial will be necessary to confirm this finding and support changes to established treatment guidelines.
Mari M. Kitahata, M.D., of the University of Washington in Seattle, has presented the findings on October 26, 2008, during the joint annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and the Infectious Diseases Society of America (IDSA) in Washington, D.C.