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  21st Conference on Retroviruses and
Opportunistic Infections
Boston, MA March 3 - 6, 2014
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Race, Age, and Transmission Risk Affect Viral Suppression Chances in DC Cohort
  CROI 2014, March 3-6, 2014, Boston
Mark Mascolini
Blacks, younger people, and heterosexually infected people proved less likely to reach an undetectable viral load on antiretroviral therapy (ART), according to results of a large prospective cohort study in Washington, DC [1]. But more than 90% of this study group did attain an undetectable load with treatment.
Surveillance indicated that Washington, DC had an HIV prevalence of 2.7% in 2011 [2]. Blacks accounted for 75% of HIV-positive people but only 48% of the population.
The new study involved 2644 HIV-positive people in the DC Cohort, a longitudinal observational cohort study with 13 participating clinical sites. The researchers included people enrolled between January 2011 and September 2013 who had two or more viral loads reported through December 2013 and an ART history. They defined viral suppression as a viral load below 200 copies at cohort enrollment or the most recent viral load measurement. Sustained viral suppression (assessed by Kaplan-Meier analysis) meant all viral loads below 200 copies during a specified period.
Of the 2644 cohort members, 2000 (76%) were men and 644 women. Overall, 2459 people (93%) achieved viral suppression, including 1867 men (93% of men) and 592 women (92% of women). Among non-Hispanic blacks, 1805 achieved viral suppression (73.7% of viral suppressions) and 177 did not (90.8% of failures) (P< 0.0001 compared with other racial/ethnic groups). Through 30 months of follow-up, Kaplan-Meier analysis determined that blacks had a significantly lower viral suppression rate than nonblacks (P < 0.0001).
Median age was significantly lower among people who did not attain suppression than in those who did (41.1 versus 47.1 years) (P < 0.001). People who failed to attain suppression also had a longer median time since HIV diagnosis (11.3 versus 10.7 years, P < 0.001) and a longer duration of antiretroviral therapy (5.7 versus 3.7 years, P = 0.03). People with public (versus private or other) insurance made up a significantly larger proportion of the suppression failure group than the suppression success group (83.6% versus 68.1%, P < 0.0001). Housing status, CD4 count at enrollment, hepatitis B or C status, and depression or other mental health problems did not distinguish suppressors from nonsuppressors.
Almost two thirds of cohort members (62%) sustained viral suppression throughout the entire follow-up period. Among blacks who attained viral suppression, about one quarter (28.8%) failed to sustain suppression. In contrast, among people of other races who attained suppression, 14.3% failed to sustain suppression. Among people who failed to sustain suppression, failure occurred after an average 24.9 months of suppression in blacks and 26.7 months in other races. Among people who did not reach a sub-200 viral load, median viral loads ranged from 5290 to 13,284 copies, and over time 15% to 22% had viral loads above 100,000 copies.
Logistic regression analysis identified four factors independently associated with ever attaining viral suppression. Every additional 5 years of age raised chances of suppression, while non-Hispanic black versus white race, heterosexual transmission versus male-to-male transmission, and perinatal transmission versus male-to-male transmission each independently cut chances of suppression. Alcohol abuse was associated with a lower chance of reaching an undetectable viral load in univariate but not multivariate analysis.
The investigators noted that analyses of additional factors such an antiretroviral exposure and resistance could further the understanding of virologic failure in this cohort. They proposed that "efforts to identify populations with disparate outcomes will allow for appropriate targeting of resources to improve viral suppression and achieve national goals."
1. Castel AD, Greenberg AE, Young H, Kalmin MM, DC Cohort Executive Committee. Disparities in viral suppression among a large cohort of HIV-Infected Persons in Washington, DC. CROI 2014. Conference on Retroviruses and Opportunistic Infections. March 3-6, 2014. Boston. Abstract 993.
2. Henry J. Kaiser Family Foundation. HIV/AIDS Policy Fact Sheet. The HIV/AIDS epidemic in Washington, DC. http://kaiserfamilyfoundation.files.wordpress.com/2013/01/8335.pdf