June 8, 2004
The researchers conducted genotyping from HIV-amplification products by automated sequencing. The scientists conducted phenotypic testing on specimens identified as having mutations previously associated with reduced antiretroviral-drug susceptibility.
Of the 1,082 HIV-1-infected study participants, most were male. Forty-six percent were African-American, and 22 percent were Hispanic. Sixty percent of male participants were men who have sex with men (MSM). Nineteen percent were recently infected.
"Although the proportion of HIV-infected persons with mutations associated with reduced antiretroviral drug susceptibility did not vary significantly by age group, city, site of enrollment, CD4+ cell count, or recency of infection," the authors found, "persons with these mutations were more likely to be white, to be MSM, and/or to have a partner taking antiretroviral medications."
The study found the overall prevalence of mutations associated with reduced antiretroviral-drug susceptibility to be 8.3 percent, but 6.1 percent in women, 4.7 percent in heterosexual men, and 12 percent in MSM. The prevalence was 5.4 percent in African Americans, 7.9 percent in Hispanics, and 13 percent in whites. For both sexual orientations and for both sexes, the researchers found, "whites had the highest prevalence of these mutations; white MSM had the highest overall prevalence (14 percent), and Hispanic and African American heterosexual men and African American women had the lowest prevalences (4.3 percent, 4.6 percent, and 4.9 percent, respectively)."
"We did find that the prevalence of mutations associated with reduced antiretroviral-drug susceptibility in persons whose infections were recent is higher than that in persons whose infections were not," the authors noted. "Although this difference is not statistically significant when all mutations are considered, some mutations, particularly those that could be confirmed phenotypically, are more likely to be found in recently infected persons."
The authors also found that, "the prevalence of these mutations was higher in persons reporting partners who took antiretroviral medications, suggesting that these viruses may have been transmitted directly from treated persons. The higher prevalence in whites and MSM may reflect better access to health care and treatment in these populations. Our results help to explain the prevalence of mutations found by others, whose study populations consisted mostly of recently or acutely infected white MSM."
"In summary," the scientists concluded, "HIV genotypic testing prior to the initiation of therapy in patients with newly diagnosed HIV infections and without AIDS would identify a substantial number of persons with virus with mutations associated with reduced antiretroviral-drug susceptibility. The prevalence of these mutations varies depending on the characteristics of the patients tested and the duration of their infections. Continued surveillance for antiretroviral-drug resistance in sufficiently large, representative samples of persons with newly diagnosed HIV will be necessary to monitor changes, over time, in the prevalence and the populations affected."