030 Brain aging and cardiovascular risk factors in chronic HIV: A longitudinal MRI study

Objectives We aimed to examine the relative contributions of HIV infection, age, and cardiovascular risk factors to subcortical brain atrophy. Methods Virally suppressed HIV+ participants with low neuropsychological confounds (n = 75) and demographically matched HIV- controls (n = 31) completed baseline and 18-month follow-up MRI scans, neuropsychological evaluation, cardiovascular assessments, and laboratory tests. HIV+ participants were evaluated for HIV associated neurocognitive disorder (HAND). Subcortical volumes were extracted with Freesurfer. Volumetric and shape analyses were conducted using linear mixed-effect models incorporating interactions between age, time, and each of HIV status, HAND status, HIV disease factors, and cardiovascular markers. Results HIV+ participants had smaller volumes of most structures compared to HIV- participants. Premature aging was evident in the pallidum using volumetric (p = 0.032) and shape analyses. Accelerated aging was observed in the caudate volumes for the more severe HAND subgroup (p = 0.008) and was associated with longer HIV duration for putamen volumes (p = 0.04). Higher CD4 counts had a protective effect on hippocampal volumes in older participants (p = 0.04). Cardiovascular measures were associated with smaller volumes across time for most structures; only the putamen demonstrated accelerated atrophy over time in HIV+ participants with higher cardiovascular risk factors (p = 0.002). Conclusion The study demonstrates a three-hit model of subcortical injury in HIV+ individuals: HIV-driven atrophy in most subcortical structures; abnormal brain aging and HIV infection synergy in the caudate and pallidum; and cardiovascular-related injury linked to diffuse premature atrophy and emerging accelerated atrophy in the putamen.