By Liz Highleyman

Over the course of the HIV/AIDS epidemic, numerous studies have compared disease progression and treatment response in people of different racial/ethnic groups. While some early research found that blacks tended to have worse outcomes than whites, later studies suggested this was likely attributable to socioeconomic factors such as access to care. More recent research has continued to provide conflicting data.

In the present study, U.S. military researchers compared virological response to highly active antiretroviral therapy between people of different racial/ethnic groups. Because people in the military tend to have similar current economic status and lifestyles, and the military health system provides similar free care for everyone, the investigators suggested that their analysis might have fewer confounding factors than prior studies.

The analysis included 1363 HIV patients -- 51% of them African-American -- who started ART between 1996 and 200 and had viral load results available 6 months after treatment initiation.

Most participants (92%) were men. As a group, the African-Americans were younger on average, less likely to be officers, more likely to have hepatitis B or C coinfection, and had lower current and nadir (lowest-ever) CD4 cell counts. However, there was no difference between the groups with regard to time from seroconversion to HIV diagnosis or ART initiation, nor in specific ART regimens. About half started a regimen containing an unboosted protease inhibitor (PI), which is generally no longer regarded as a preferred type of regimen due to inadequate potency.

The odds of achieving viral load suppression 6 and 12 months after starting ART were determined by multivariate logistic regression. Undetectable viral load was defined as HIV RNA < 400 copies/mL. Time-to-event methods were used to compare maintenance of virological suppression.

Results

	6 months after starting ART, 63% of African-Americans achieved viral load < 400 copies/mL, compared with 75% of people of European descent.
	After adjusting for multiple demographic and HIV-related factors, African-Americans were 40% less likely than whites to achieve viral suppression 6 months after ART initiation (odds ratio 0.6; P < 0.001).
	This was still the case after 12 months of treatment (odds ratio 0.6; P = 0.002).
	African-Americans also experienced a smaller average decrease in viral load than whites (1.6 vs 1.9 log10, respectively).
	Once undetectable viral load was achieved, however, there was no difference between blacks and whites in time to virological failure.

Based on these findings, the study authors concluded, "Despite similar durations of HIV infection and equal access to health care, African-Americans were significantly less likely to achieve viral suppression compared with European-Americans."

Seeking to explain these results, the researchers suggested in their discussion that among patients using unboosted PIs, "slight differences in absorption, distribution, metabolism, or elimination of these older regimens between ethnicities may have lead to different side effects, toxicities or potencies and may have contributed to the differences in virological suppression" -- differences that might no longer be apparent when stronger regimens are used.

Infectious Disease Clinical Research Program of the Uniformed Services University of the Health Sciences, Bethesda, MD; Infectious Disease Service, Walter Reed Army Medical Center, Washington, DC; Division of Biostatistics, University of Minnesota, Division of Biostatistics, Minneapolis, MN; Infectious Disease Service, National Naval Medical Center, Bethesda, MD; Infectious Disease Service, San Antonio Military Medical Center, San Antonio, TX; Infectious Disease Service, Naval Medical Center San Diego, San Diego, CA.

10/20/09

Reference
A Weintrob, GA Grandits, BK Agan, and others Virologic Response Differences Between African Americans and European Americans Initiating Highly Active Antiretroviral Therapy With Equal Access to Care. Journal of Acquired Immune Deficiency Syndromes. September 11, 2009 (epub ahead of print). (Abstract).