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Blacks Have 50% Lower Chance of HIV Control Than Nonblacks in 6-Study Analysis
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52nd ICAAC, September 9-12, 2012, San Francisco
Mark Mascolini
Virologic response to numerous protease inhibitor and nonnucleoside regimens in a meta-analysis of six randomized trials proved consistently worse in blacks than whites [1]. The finding confirms earlier results of of a 5-study AIDS Clinical Trials Group (ACTG) analysis [2].
Because of a long-noted disparity in virologic suppression rates of blacks and whites in contemporary antiretroviral trials, researchers from Dallas, Philadelphia, and Baltimore planned this systematic review of trials that addressed this issue. The analysis included trials presented from January 1996 through December 2011 in developed countries and reporting virologic response differences between blacks and nonblacks.
The investigators identified 8 randomized trials and one meta-analysis involving 8040 patients, 3529 of them (44%) black. In all of these studies, blacks had a lower virologic response rate or higher risk of virologic failure. Six trials had a similar design, including 96-weeks outcomes and a sub-50-copy response endpoint analyzed by the time-to-virologic response (TLOVR) method. The six trials were GS 903, GS 934, ARTEMIS, HEAT, ECHO, and THRIVE. Results of ECHO and THRIVE were combined for analysis.
In all of these studies, a lower proportion of blacks than nonblacks had a viral load below 50 copies at week 96 by TLOVR analysis. And in all of these studies a higher proportion of blacks than nonblacks failed to attain virologic suppression at week 96.
In four of the five meta-analysis studies (with ECHO and THRIVE combined), odds of having a sub-50-copy viral load at week 96 were significantly lower in blacks than nonblacks. In the remaining study, ARTEMIS, the virologic suppression difference between blacks and nonblacks just exceeded the bounds of statistical significance. The overall analysis indicated about 50% lower odds of a sub-50 viral load at 96 weeks in blacks than nonblacks:
Odds ratio for viral load below 50 copies at 96 weeks (blacks versus nonblacks):
Overall: odds ratio (OR) 0.52, 95% confidence interval (CI) 0.44 to 0.62, P < 0.0001
GS 903: OR 0.43, 95% CI 0.29 to 0.66
GS 934: OR 0.63, 95% CI 0.41 to 0.96
ECHO/THRIVE: OR 0.50, 95% CI 0.38 to 0.67
ARTEMIS: OR 0.58, 95% CI 0.33 to 1.03 (not significant)
HEAT: OR 0.53, 95% CI 0.39 to 0.75
The authors noted that genetic factors, metabolic differences, and social variables are usually advanced to explain lower virologic response rates in blacks than nonblacks. Cited social factors include education, income, mental health, health literacy, and food security. But response disparities persisted in studies that tried to control for some social factors. And genetic and metabolic differences "have not been able to explain why this difference persists across multiple trials and multiple regimens."
Furthermore, adherence does not appear to be the determining variable. A similar meta-analysis of ACTG studies determined that black race (compared with white race) was associated with a 40% higher risk of virologic failure on a first-line regimen [2]. Neither recent adherence nor demographic, medical, or social factors accounted for the higher failure risk in blacks.
"Given the current demographics of the HIV epidemic," the researchers concluded, "it is important that issues contributing to this disparity be explicitly determined and addressed."
IAC: A Meta-Analysis of the Differences in ART Virologic Failure Rates in Randomized Clinical Trials: Do Blacks Consistently Have Lower ART Efficacy and Poor Treatment Outcomes? - (08/06/12)
A Meta-Analysis of the Differences in ART Virologic Failure Rates in Randomized Clinical Trials: Do Blacks Consistently Have Lower ART Efficacy and Poor Treatment Outcomes? - (08/06/12)
HIV Stats Point to Need for Annual Testing- "particularly blacks/African Americans and injection drug users" - (07/10/12)
Trends in the Black-White Life Expectancy Gap, 2003-2008: HIV is a leading cause in racial health dispaity - (06/14/12)
References
1. Evans C, Kwakwa H, Spencer D, et al. Meta analysis of differences in viral suppression by race in clinical trials. 52nd Interscience Conference on Antimicrobials and Chemotherapy (ICAAC). September 9-12, 2012. San Francisco. Abstract H-881.
2. Ribaudo H, Smith K, Robbins G, et al. Race differences in the efficacy of initial ART on HIV infection in randomized trials undertaken by ACTG. 18th Conference on Retroviruses and Opportunistic Infections. February 27-March 2, 2011. Boston. Abstract 50. http://retroconference.org/2011/Abstracts/40099.htm; http://www.natap.org/2011/CROI/croi_04.htm.
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