Abstract
Cognitive impairment (CI) remains common despite access to combination antiretroviral therapy (cART); it has been linked to HIV-specific, HIV-related, and HIV-unrelated factors. Insulin resistance (IR) was associated with CI in the early cART era, when antiretroviral medications had greater mitochondrial and metabolic toxicity. We sought to examine these relationships in the current cART era of reduced antiretroviral toxicities. This study examined IR among non-diabetics in relation to a 1-h neuropsychological test battery among 994 women (659 HIV-infected and 335 HIV-uninfected controls) assessed between 2009 and 2011. The mean (standard deviation (SD)) age of the sample was 45.1 (9.3) years. The HIV-infected sample had a median interquartile range (IQR) cluster of differentiation 4 (CD4) T-lymphocyte count of 502 (310-727) cells/μL, and 54 % had undetectable plasma HIV RNA levels. Among all, the homeostasis model assessment (HOMA) of IR ranged from 0.25 to 37.14. In adjusted models, increasing HOMA was significantly associated with reduced performance on Letter-Number Sequencing (LNS) attention task (β = -0.10, p < 0.01) and on Hopkins Verbal Learning Test (HVLT) recognition (β = -0.10, p < 0.01) with weaker but statistically significant associations on phonemic fluency (β = -0.09, p = 0.01). An HIV*HOMA interaction effect was identified on the LNS attention task and Stroop trials 1 and 2, with worse performance in HIV-infected vs. HIV-uninfected women. In separate analyses, cohort members who had diabetes mellitus (DM) performed worse on the grooved pegboard test of psychomotor speed and manual dexterity. These findings confirm associations between both IR and DM on some neuropsychological tests and identify an interaction between HIV status and IR.