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CROI 2012: U.S. Black Women Have Higher Rates of HIV Infection and AIDS Death

Urban black women in the U.S. are 5 times more likely to become infected with HIV than previously estimated, and are twice as likely to die of AIDS-related causes, according to 2 posters presented this month at the 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012) in Seattle.

HIV Incidence

Experts have estimated that women account for about 25% of new HIV infections in the U.S., about two-thirds of whom are black. But researchers need more precise incidence data when conducting prevention trials, in order to determine whether the intervention under study is beneficial.

Sally Hodder and fellow investigators with the HIV Prevention Trials Network 064 ISIS study team looked at the rate of new HIV infections among women in 6 U.S. cities: Atlanta, Baltimore, Newark, Raleigh-Durham, New York City, and Washington, DC. They recruited more than 2000 women using ethnographic mapping of venues frequented by at-risk women in communities with widespread poverty and high HIV prevalence rates. They enrolled women without a prior self-reported HIV diagnosis who had at least 1 individual or partner risk factor.

Most participants (88%) were blacks, 12% were Latina/Hispanic, and 8% were white. The median age was 29 years (range 18 to 44), 44% had an annual income below $10,000/year and 37% had less than a high school education. They had a median of 2 sex partners within the past 6 months and just 18% reported using a condom the last time they had vaginal sex.

Individual risk factors included binge drinking (40%), cocaine use (17%), and recent anal sex (38%). Partner risk factors included incarceration within the past 5 years (59%) and binge drinking (56%). Only 1% had recently had sex with a partner known to be HIV positive, but 41% had sex with partners of unknown status.

The women were followed for 6 to 12 months, receiving regular HIV testing and completing computer-assisted self interviews; testing for acute infection was performed retrospectively using specialized tests.

Results

• 32 out of 2099 women (1.50%) were newly diagnosed with HIV infection at enrollment.
• 2 additional women were later found to have had acute HIV infection at baseline, for an estimated annual incidence rate of 2.52% (95%CI 0.60 to 10.7).
• 4 women acquired HIV during follow-up, for an estimated annual incidence rate of 0.24% (95%CI 0.09 to 0.65).
• The annual incidence estimate based on acute infection at enrollment was significantly higher than the estimate based on seroconversion during follow-up.

The researchers concluded that recruitment at "hotspots" of HIV infection could identify women with few partners but a high level of risk behavior.

These findings show that HIV infection rates within this selected population are substantially higher than overall incidence rates for African-American adolescents or women, they elaborated in a press release issued by Johns Hopkins School of Medicine.

"HIV incidence in HPTN 064 (ISIS) was substantially (5 times) higher than CDC 2009 annual HIV incidence estimate for U.S. black women (0.05%) and comparable to estimated HIV adult incidence rates in parts of sub-Saharan Africa (Congo 0.28% and Kenya 0.53%), underscoring the urgency of conducting prevention trials among women at risk for HIV infection in the U.S.," the study team summarized.

"This study clearly shows that the HIV epidemic is not over, especially in urban areas of the United States, like Baltimore, where HIV and poverty are more common, and sexually active African-American men and women are especially susceptible to infection," said Baltimore principal investigator Charles Flexner from Johns Hopkins.

AIDS Mortality

In the second study, Kerry Murphy and colleagues with the long-term prospective Women's Interagency HIV Study (WIHS) looked at disease progression, AIDS-related illness, and death among women on combination antiretroviral therapy (ART).

Some prior observational studies have seen greater likelihood of disease progression and death among women compared with men, and among blacks compared with whites. This has largely been attributed to socioeconomic factors such as late diagnosis, less access to care, and poorer adherence, rather than biological factors. A prior WIHS study saw a higher rate of AIDS-related death among black compared with white women on ART, but the difference did not reach statistical significance.

In the present analysis, the researchers assessed the association between race and clinical outcomes among 1471 HIV positive women on continuous combination ART.

Results

• In an adjusted analysis, black women were significantly more likely than white women to die from AIDS-related causes, with an adjusted hazard ratio (HR) of 2.03, or about twice the risk.
• The cumulative incidence of AIDS-related death at 10 years was 16.0% for black women compared with 8.2% for white women.
• Black women were also significantly more likely to develop a new AIDS-defining illness (adjusted HR 1.68, or 68% higher risk; P = 0.005).
• Rates of death due to non-AIDS causes were similar among black and white women (adjusted HR 0.83, reflecting a slight but non-significant reduction in risk).
• In addition to race, other significant independent predictors of AIDS-related death included:
  • Depression: adjusted aHR 2.13;
  • Higher peak HIV viral load: adjusted HR 1.83;
  • Lower nadir (lowest-ever) CD4 cell count: adjusted HR 0.65 per 100 cells/mm³);
  • Hepatitis C virus coinfection with detectable HCV viral load: adjusted HR 1.66;
  • History of illegal drug use: adjusted HR 1.64.
• Additional independent predictors of AIDS-defining illness included:
  • Prior AIDS-defining illnesses: adjusted HR 2.10;
  • Higher peak HIV viral load: adjusted HR 1.57;
  • Smoking: adjusted HR 1.64.
• Black women and depressed women reported significantly lower ART adherence.
• However, further analysis showed that the association between black race and AIDS-related death remained significant after adjusting for differences in adherence (adjusted HR 2.35).
• Nevertheless, very good adherence (> 95%) protected against AIDS-related death (adjusted HR 0.30, or 70% lower risk).
• Significant predictors of poorer adherence included black race, depression, injection drug use, any illegal drug use, smoking, and lower education level, while low nadir CD4 cell count predicted better adherence.

Among continuous ART users, "black women were more than twice as likely to die from AIDS and more likely to experience an incident AIDS-defining illness compared to white women," the researchers concluded.

"Genetic polymorphisms in drug metabolism and transport that differ by ancestry may be playing a role in lower adherence and higher AIDS deaths in black women,"they suggested. For example, people of African descent are more likely to have genetic variations involved in drug transport and metabolism that may impact outcomes on ART.

"Future studies examining host genetic traits in these women are important and may inform selection of future HAART regimens for women of African ancestry," the researchers recommended.

 3/21/12

References

S Hodder, J Justman, J Hughes, et al. (HIV Prevention Trials Network 064 Study Team). The HPTN 064 (ISIS Study) -- HIV Incidence in Women at Risk for HIV: US.19th Conference on Retroviruses and Opportunistic Infections (CROI 2012). Seattle, WA. March 5-8, 2012. Abstract 1048.

K Murphy, D Hoover, Q Shi, et al. The association of race with death from AIDS in continuous HAART users: WIHS. 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012). Seattle, WA. March 5-8, 2012. Abstract 1045.

Other Source

Johns Hopkins School of Medicine. HIV Rates for U.S. Urban Black Women Five Times Higher than Previously Estimated. Press release. March 8, 2012.