African Americans are 40% less likely than individuals of European ancestry to have an undetectable viral load six and twelve months after starting HIV treatment, investigators from the US military report in a study published in the online edition of the Journal of Acquired Immune Deficiency Syndromes.
Almost half the patients in the study started HIV treatment with an unboosted protease inhibitor, and the researchers noted that there were poorer virological outcomes in patients whose initial antiretroviral therapy regimen included such drugs rather than an NNRTI.
They suggest, therefore, “slight differences in absorption, distribution, metabolism, or elimination of these older regimens between ethnicities may have led to different side-effects, toxicities or potencies and may have contributed to the differences in virological suppression.”
Several studies have shown that African-American patients are less likely than those of white race to achieve and maintain an undetectable viral load after initiating HIV treatment.
However, these results are limited as African Americans are disproportionately affected by poverty and are less likely to access HIV treatment and care than patients of European descent.
US military personnel receive free HIV treatment and care, have secure housing and food, and are prohibited from using drugs. They therefore provide a population in which the virologic efficacy of HIV treatment according to race can be studied with minimal confounding factors. Regular HIV testing and follow-up also means that important data are available to investigators on the duration of HIV infection and on HIV disease progression.
Investigators therefore looked at the virologic response to antiretroviral therapy in military personnel who initiated HIV treatment between 1996 and 2007.
The study included approximately 650 African Americans and 650 European Americans.
African-American patients were younger, less likely to be officers, were more likely to have viral hepatitis co-infection, and had both lower nadir CD4 cell counts and CD4 cell counts at the time HIV treatment was started.
Six months after starting HIV treatment, 63% of African Americans had an undetectable viral load (below 400 copies/ml) compared to 75% of European Americans. This difference was significant (p
Differences in virologic response were still present when the investigators restricted their analysis to patients who did not change their HIV treatment.
Furthermore, the investigators found that African Americans had smaller drops in viral load than patients of European origin (1.6 log10 vs 1.9 log10).
After adjusting for possible confounding factors, African Americans were found to be 40% less likely to have a virological response to HIV treatment than European Americans six months (odds ratio, 0.6; 95% CI, 0.4 to 0.8, p
However, once viral suppression was achieved both African Americans and European Americans maintained an undetectable viral load for an equal amount of time.
“This study adds to the body of evidence that African Americans do not have the same virologic response to HAART as European Americans,” comment the investigators.
They conclude, “it is imperative that we understand why the HAART response rates are lower in African versus European Americans to optimize therapy for all HIV-infected individuals. More efforts need to be focused on psychological, social and cultural and genetic differences between ethnicities and how these may impact response to therapy.”
Weintrob AC et al. Virologic response differences between African Americans and European Americans initiating highly active antiretroviral therapy with equal access to care. J Acquir Immune Defic Syndr (online edition), 2009.