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  Reported by Jules Levin
IDWeek Oct 26-30
New Orleans 2016
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Viral Rebound Rate 22% in US Group--Higher in Blacks and With Lower CD4s
  IDWeek 2016, October 26-30, 2016, New Orleans
Mark Mascolini
Nearly one quarter of a 2013-2015 group of US HIV patients had a virologic rebound in an 828-person analysis [1]. Blacks, in-hospital patients, and those with a CD4 count below 200 had independently higher odds of viral breakthrough.
Potent, convenient, and diverse antiretroviral combinations available today give more treated people an opportunity to reach an undetectable viral load. But viral rebounds remain a threat because of lapsed adherence, drug-drug interactions, and other reasons. Researchers at Nashville's Vanderbilt University and Detroit's Henry Ford Hospital conducted this retrospective analysis to determine rebound rate and predictors in a contemporary HIV population.
This retrospective study involved treatment-experienced adults who had a viral load below 50 copies while attending an HIV clinic between January 2013 and June 2015. All participants had at least two viral load measurements during the study period. The researchers defined viral rebound as (1) two consecutive viral loads at or above 50 copies or (2) one viral load at or above 200 copies after an undetectable load.
Among 828 virally suppressed people, 183 (22%) had a rebound during the study period. Compared with people who maintained a sub-50-copy viral load, rebounders were younger (average 45.5 versus 49.1 years, P = 0.001), had a lower CD4 count (average 376 versus 501, P = 0.001), had a lower CD4/CD8 ratio (average 0.65 versus 0.87, P = 0.001) and were more likely to be black (73% versus 60%, P = 0.01), to be hospitalized (34% versus 22%, P = 0.001), to have a substance abuse history (44% versus 34%, P = 0.02), and to use Medicaid (44% versus 33%, P = 0.01).
Contrary to some previous research, taking a one-pill once-daily regimen did not favor good viral control. In fact, once-daily regimens were marginally more common among rebounders. Proportions of rebounders and nonrebounders taking a one-pill once-daily regimen were 53% and 48% (P = 0.27) and proportions taking any once-daily regimen were 79% and 72% (P = 0.06). Other factors that did not differ between rebounders and nonrebounders were gender, HCV positivity, income, and mood disorder prevalence.
Multivariate analysis identified three independent rebound predictors: black race (adjusted odds ratio [aOR] 1.60), hospitalization (aOR 1.56), and CD4 count below 200 (aOR 2.16). There was a trend toward higher rebound odds in people younger than 50 rather than older (aOR 1.35).
"Despite highly effective therapies," the researchers concluded, "failure to maintain viral suppression continues to be a frequent occurrence, influenced by various sociodemographic and clinical factors."
1. Bourgi K, Brar I, Markowitz N. Predictors of rebound viremia in treatment experienced patients with undetectable viral load. IDWeek 2016, October 26-30, 2016, New Orleans. Abstract 1546.