The relationships between ethnicity, sex, risk group,and virus load in HIV-1 antiretroviral-naive patients

Plasma virus load in HIV-1 infected patients is an important predictor of the progression of HIV infection.

When it is combined with a CD4+ lymphocyte count, health professionals use it “to estimate the stage of disease and to guide such therapeutic decisions as when to start and when to change highly active antiretroviral therapy,” according to researchers. “It is unclear, however, to what extent virus load varies according to factors such as sex and ethnicity,” the researchers wrote. The objective of this cross-sectional study, according to the report, “was to examine the relationships between ethnicity, sex, risk group, and virus load in HIV-1-seropositive patients attending a major HIV unit in south London.”

The researchers included all HIV-1-seropositive patients from St. Thomas’ Hospital, London, between May 1997 and February 1999 who were antiretroviral naive at the time of their initial virus load measurement, and who had virus load measured within three months of a CD4+ count. The medical records of all 322 patients were reviewed for initial virus load, CD4+ lymphocyte count, sex, age at diagnosis, ethnicity, probable mode of exposure to HIV, source of referral for HIV testing and whether the patients had a diagnosis of AIDS upon enrolment. Of the study’s participants, 54 percent were white. In that group, 72.3 percent were gay men and 12.7 percent were women. “Black Africans formed the second largest ethnic group (35.1%): All had a heterosexual risk for infection, and 63.7% were women. …An initial diagnosis of AIDS was made at the time of presentation in 19.6% of patients,” the researchers wrote. HIV-1 RNA was measured in all participants. The researchers reported that their analyses “revealed no difference in initial virus load” with respect to ethnicity, sex or risk group. AIDS patients had higher virus loads than those without AIDS, and there was a strong correlation between the CD4+ lymphocyte count and virus load. However, they reported, “The initial CD4+ lymphocyte count was significantly different with respect to ethnicity (white patients had higher CD4+ lymphocyte counts than other patients; P<.001) and risk group (CD4+ lymphocyte counts were higher in gay men than in other patients; P<.001).”

The researchers concluded that through “multivariate analysis, variables independently related to virus load were CD4+ cell count (P = .001), being black African (P = .001), having a nonsexual risk for HIV infection (P = .03), and having AIDS (P = .05). Neither sex nor age was a significant predictor of initial virus load after adjusting for other variables. For a given CD4+ cell count, black Africans and people who contracted HIV nonsexually presented with a virus load lower than that of patients in other groups. Because virus load may need to be interpreted differently according to ethnicity, this may affect decisions on when to initiate antiretroviral therapy and how to interpret clinical trial results.”

Jacky Saul; Jo Erwin; Caroline A Sabin; Ranjababu Kulasegaram; Barry S Peters. Journal of Infectious Diseases (15.05.01) Vol. 183; P 1518-21.