July 11, 2000
Helping to clarify a long-standing issue, a study by researchers at Johns Hopkins shows that women carry lower levels of HIV in their blood than men, especially during early phases of the infection, but have the same risk as men of developing AIDS. One consequence of the findings: viral load thresholds used by doctors to begin anti-retroviral drug therapy could result in more men getting offered treatment than women, particularly early in the course of infection.
"You would assume that if women start out with a lower viral load than men, they would have a lower risk of progressing to AIDS, but they have the same risk," says Timothy Sterling, M.D., an assistant professor of infectious diseases at the Johns Hopkins Medical Institutions. Sterling presents the research on July 11 at the 13th International AIDS Conference in Durban, South Africa.
Currently, doctors generally offer anti-retroviral treatment to patients when tests indicate greater than 20,000 copies of HIV per milliliter of blood. The Hopkins team found that while both men and women had the same risk of developing AIDS, women had lower viral loads than men during the first few years of becoming HIV positive. While men who progressed to AIDS had average viral loads of roughly 78,000 copies per ml in the first year, women who progressed to AIDS only had 17,000 copies per ml. Women continued to have lower HIV levels than men in subsequent years, but by the fourth year, the differences tended to dissipate.
Over the past several years, various studies have yielded conflicting results as to whether viral loads differ between HIV-positive men and women. Using data from the AIDS Linked to Intravenous Experience (ALIVE) study of 3,380 intravenous drug users, Sterling and his colleagues studied individuals who had contracted HIV within 12 months of a previous visit and before December 1 of 1997. Out of the total ALIVE group, 202 qualified for their study, 156 men and 46 women.
"The current viral load cutoffs for the initiation of anti-retroviral therapy were developed based on data from men," says Sterling. "This study demonstrates that current cutoffs would result in sex-biased differences in treatment eligibility, and that therefore current guidelines should be reassessed, particularly early in the course of infection.
Co-investigators of the study include Jacquie Astemborski, Thomas Quinn, Donald Hoover, Joseph Margolick, Chris Urban, Denise McNairn, Steffanie Strathdee and David Vlahov from the Johns Hopkins University School of Public Health and School of Medicine. The study was funded by the National Institute on Drug Abuse of the National Institutes of Health.
Related Web Sites:
Hopkins AIDS Service: http://www.hopkins-aids.edu
XIII International AIDS Conference: http://www.aids2000.com/