Differential Effects of an AIDS Defining Illness and Chronic HIV Infection on Gray Matter Volume.

BACKGROUND Age, HIV infection, illicit drug use, and CNS opportunistic infections all can affect brain structure, with the striatum being particularly sensitive to HIV effects. Nevertheless, the impact of non-CNS AIDS defining illness (ADI) on brain structure has been less investigated. We examined ADI and HIV effects on brain volume. METHODS In a cross-sectional study, including 95 virally-suppressed seropositive and 84 demographically-matched, seronegative participants, we examined serostatus and ADI effects. Cortical and subcortical GMV ROIs were estimated with computational neuroanatomy techniques applied to high resolution, T1-weighted MRI data. Linear regression was used to model HIV serostatus and ADI effects on global and regional GMV, adjusting for age, sex, CD4 nadir, drug use and total intracranial volume. RESULTS While HIV serostatus was associated with lower striatal volume (B = -0.59; 95% CI = [-1.08 - -0.10]), co-occurring ADI was independently associated with lower striatal volume (B=-0.73; 95% CI =[-1.36 - -0.09]). ADI was also associated with lower global (B = -19.35; 95% CI = [-32.42 - -6.29]) and regional GMV. CONCLUSIONS While HIV infection is associated with a localized effect on striatal structure, having a prior ADI is a strong predictor of smaller global and regional GMV. The lack of interaction between HIV serostatus or ADI with age suggests that chronic HIV infection and ADI have independent effects on brain structure, without associated accelerated lower volume with age. ADI history should be incorporated into statistical adjustments in HIV neuroimaging analysis. These findings also lend support to current HIV treatment guidelines urging prompt ART initiation after HIV diagnosis.