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Background:  Occurrence of AIDS-defining illness and death, and longitudinal changes in HIV-1 RNA and CD4⁺ cell counts following initiation of highly active antiretroviral therapy (HAART) among different racial groups have not been well described.

Methods:  In 937 HIV-infected participants initiating HAART in the Women’s Interagency HIV Study, differences by race in virologic and immunologic response and failure, and incident AIDS-defining illness and death were analyzed by Cox regression.  Race was defined as black (Hispanic and non-Hispanic), white (Hispanic and non-Hispanic) and Hispanic not self-identifying as black or white.

Results:  In median 4.3 years, 562 (60.0%) women attained a virologic response of <80 copies/mL, 718 (76.6%) attained an immunologic response of at least 100 cells greater than their nadir pre-HAART CD4⁺ cell count, 61.3% of virologic responders had virologic rebound to >1000 copies/mL, 35.2% of immunologic responders had a CD4⁺ cell count less than their nadir pre-HAART CD4⁺, 37.7% developed an incident AIDS-defining illness, and 140 (14.9%) died following HAART initiation, with 53 deaths from AIDS, 35 from non-AIDS causes, 6 of indeterminate cause, and 46 of unknown cause. In multivariate analyses, compared to African-American women, white women had more rapid and more durable virologic (p = 0.016, 0.021 respectively) and immunologic (p = 0.043, 0.042, respectively) responses, and Hispanic women were significantly less likely (Relative Hazard [RH] = 0.73, 95% Confidence Interval (CI) = 0.55, 0.97) to have an incident AIDS-defining illness. Hispanic (RH = 0.63, CI = 0.39, 1.03, p = 0.063) and white women (RH = 0.73, CI = 0.46, 1.18, p = 0.200) were less likely to die after HAART initiation, compared to African American women. In the 53 deaths from AIDS, the difference between white and African American women was of similar magnitude as for all deaths, but was not statistically significant (multivariate RH = 0.54, p = 0.167). Hispanic women had a lower hazard of a non-AIDS death, with marginal statistical significance.

Conclusions:  In this study of nearly 1000 women initiating HAART in the United States, white women had a higher incidence and longer duration of virologic and immunologic response after HAART initiation compared to African American women. Hispanic and white women were also less likely to die after HAART initiation. These differences in outcome may result from biological or cultural factors and warrant further investigation in additional cohorts and clinical trials.

Keywords: Race; Response to HAART; Progression