HIV, aging, and cognition: emerging issues

Abstract

The prevalence of HIV-associated neurocognitive disorder has not changed from the pre- to the potent antiretroviral therapy era, remaining at approximately 50%. In research settings, mild neurocognitive disorder (MND) and so-called asymptomatic neurocognitive impairment (ANI) are now more common than HIV-associated dementia. The diagnosis of ANI is misleading because functional deficits, when tested in a laboratory, and degree of neuropsychologic testing abnormalities are often comparable in patients with ANI and those with symptomatic MND. Age-related comorbidities increase the risk of cognitive impairment in HIV infection. In a cohort of patients aged 60 years or older with excellent antiretroviral therapy adherence, correlates to cognitive impairment were apolipoprotein (Apo) E4 genotype and a novel measure of the effectiveness of antiretroviral drugs in monocytes, the monocyte efficacy (ME) score, with trend associations for diabetes and nadir CD4+ cell count. Management of impairment includes ensuring that patients are on and adhere to antiretroviral therapy and addressing comorbidities. Switching from effective and well-tolerated antiretroviral therapy for patients with mild cognitive impairment is not routinely recommended, but this must still be addressed on a case-by-case basis. This article summarizes a presentation by Victor G. Valcour, MD, at the IAS-USA continuing education program held in Atlanta, Georgia, in April 2013.

Figure 1.

Probability of cognitive impairment by CD4+ cell count (below, at, or above 200 cells/μL) and plasma HIV RNA level (detectable or not) according to the presence of incidental, contributing, or confounding comorbidities. Adapted from Heaton et al.

Figure 2.

Similar deficits in patients with asymptomatic neurocognitive impairment (ANI) and symptomatic impairment on neuropsychologic testing performance (mild neurocognitive disorder [MND] and HIV-associated dementia combined) in the University of California San Francisco (UCSF) HIV Over 60 Cohort (top). Similar deficits on functional performance among patients with ANI and MND (bottom). Adapted from Chiao et al.

Figure 3.

Conversion to symptomatic impairment over time in 347 patients with asymptomatic neurocognitive impairment (ANI) or normal findings on neuropsychologic testing in the CHARTER (Central Nervous System HIV Antiretroviral Therapy Effects Research) cohort. Adapted with permission from Grant et al.

Figure 4.

Association of apolipoprotein (Apo) E4 with poorer neuropsychologic testing performance shown by Z scores in patients in the University of California San Francisco (UCSF) HIV Over 60 Cohort (adjusted for CD4+ cell count, nadir CD4+ cell count, years HIV seropositive, and plasma HIV RNA level). Adapted with permission from Atputhasingam et al.