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"Asymptomatic" HIV Neurocognitive Impairment Not So Benign After All?
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19th Conference on Retroviruses and Opportunistic Infections, March 5-8, 2012, Seattle
Mark Mascolini
HIV-positive people with neurocognitive impairment designated "asymptomatic" had deficits in employment capacity comparable to those of people with symptomatic HIV-associated neurocognitive disorder (HAND), according to results of a 573-person comparison of three groups in the US CHARTER Cohort [1]. The findings have implications for neurocognitive impairment workup in people with HIV.
CHARTER investigators noted that HAND still affects as many as half of HIV-positive people in the United States, and asymptomatic neurocognitive impairment is the most prevalent form of HAND, affecting about one third of the US HIV population [2]. Asymptomatic impairment is asymptomatic in the sense that it does not affect self-reported everyday functioning compared with symptomatic neurocognitive impairment, which does significantly affect everyday functioning. Because self-report may be influenced by mood and may not distinguish mild declines in everyday functioning [3], the CHARTER group planned this analysis.
The study involved 573 HIV-positive CHARTER cohort members who underwent neuropsychological evaluation with a seven-domain battery of tests. Participants also self-reported cognitive complaints and declines in everyday functioning with standard tools. This evaluation determined that 340 people (59%) were neuropsychologically normal, 175 (31%) had asymptomatic neurocognitive impairment, and 58 (10%) had HAND, including 14 with HIV-associated dementia. The CHARTER team also used standard tests to gauge employment capacity, medication management skills, and current depressive symptoms.
The normal, asymptomatic, and symptomatic HAND groups were equivalent in average age (45 overall), proportion of men (82%, 71%, 79%, P = 0.15), proportion of whites (43%, 42%, and 50%), median viral load in plasma and cerebrospinal fluid (around 50 copies across the board), and proportion on antiretroviral therapy (78%, 78%, and 71%). The normal group had marginally less education than the asymptomatic and HAND groups (12.8, 13.3, and 13.2 years, P = 0.06). Current average CD4 count (482.5, 444.5, and 560.3) was significantly lower in the asymptomatic group than in the HAND group (P = 0.01).
The neurocognitively asymptomatic group also had a marginally lower nadir CD4 count (196.4, 171.5, and 231.2, P = 0.06). The normal group and the asymptomatic group had a significantly lower (better) score on the Beck Depression Inventory-II than the HAND group (11.0, 10.2, and 19.9, P < 0.001). And the normal group had a significantly higher proportion with a diagnosis of lifetime substance abuse or dependence (77%, 66%, and 69%, P = 0.03).
Employment capacity was significantly greater in the neuropsychologically normal group than people with asymptomatic neurocognitive impairment or symptomatic HAND (P < 0.05), while the latter two groups did not differ significantly from each other. After statistical adjustment for current CD4 count and depressive symptoms, pairwise comparison determined employment capacity was significantly better in the normal group than in the asymptomatic group (P < 0.001) but statistically equivalent in the asymptomatic group and the HAND group (P > 0.10).
This logistic regression model also determined that Beck Depression Inventory-II scores differed significantly across groups (P < 0.001). But medication management skills did not differ significantly across groups (P > 0.05).
The CHARTER team concluded that people with asymptomatic neurocognitive impairment have deficits in employment capacity comparable to those of people with symptomatic HAND when compared with neuropsychologically normal HIV-positive people. Therefore, the investigators suggested, asymptomatic neuropsychological impairment "may be less benign than is widely perceived."
The CHARTER researchers believe their findings "highlight the shortcomings of self-report based [neuropsychological] diagnoses and the importance of incorporating performance-based tests of everyday functioning when diagnosing HAND."
References
1. Blackstone K, Moore D, Woods S, et al, and the CHARTER Group. How "asymptomatic" is HIV-associated asymptomatic neurocognitive impairment? 19th Conference on Retroviruses and Opportunistic Infections. March 5-8, 2012. Seattle. Abstract 497. http://www.retroconference.org/2012b/PDFs/497.pdf.
2. Heaton RK, Clifford DB, Franklin DR, et al, CHARTER Group. HIV-associated neurocognitive disorders persist in the era of potent antiretroviral therapy: CHARTER Study. Neurology. 2010;75:2087-2096. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995535/?tool=pubmed.
3. Blackstone K, Moore DJ, Heaton RK, et al, CHARTER Group. Diagnosing symptomatic HIV-associated neurocognitive disorders: self-report versus performance-based assessment of everyday functioning. J Int Neuropsychol Soc. 2012;18:79-88.
How "asymptomatic" is HIV-associated Asymptomatic Neurocognitive Impairment?
K. Blackstone1, D.J. Moore2, S.P. Woods2, E.E. Morgan2, D.R. Franklin2, R.J. Ellis2, S.S. Letendre2, I. Grant2, R.K. Heaton2, & the CHARTER Group
1SDSU/UCSD Joint Doctoral Program in Clinical Psychology; San Diego, CA, USA
2University of California, San Diego; San Diego, CA, USA
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