Should AIDS therapy start at higher cell counts?

New research suggests that AIDS therapy should be initiated at higher CD4 levels than current guidelines recommend.

In the study, published in the Sept. 15 issue of The Journal of Infectious Diseases, researchers wanted to reevaluate the optimal time to initiate highly active antiretroviral therapy (HAART). Current guidelines recommend initiating therapy when CD4 counts are between 200/µL and 350/µL.

The researchers followed 583 HIV-seropositive and 920 HIV-seronegative injection drug users from 1997 to 2000. HIV-seropositive participants were categorized according to receipt of HAART (either initiated or switched to HAART) and initial CD4 cell count. Survival analysis that included delayed-entry and Cox proportional-hazards models was used to evaluate the effect of HAART, with adjustments for factors associated with access to HAART.

Mortality among HIV-infected injection drug users with CD4 cell counts greater than 350/µL who received HAART was similar to that of HIV-seronegative injection drug users. In addition, both groups had lower mortality than HIV-infected subjects with CD4 cell counts greater than 350/µL who did not receive HAART and those with CD4 counts between 200/ìL and 350/µL who did receive such therapy.

"Survival of HIV-seropositive participants receiving HAART approximated that of HIV-seronegative participants only when therapy was given at CD4 cell counts [are greater than] 350 cells/µL," the researchers say. "These data, restricted to seronegative injection drug users, suggest initiating or switching to HAART at higher CD4 cell levels than are currently recommended."

In an accompanying editorial, Mauro Schechter, MD, PhD, professor of infectious diseases at Federal University of Rio de Janeiro in Brazil, recognized the importance of the study, although he said it had several limitations. He cautioned that the evidence still is mixed about what CD4 cell level to start HAART, but that the guidelines may change with further study data.