Background
Current HIV treatments are successful at suppressing plasma HIV RNA to undetectable levels for most adherent patients. Yet, emerging evidence suggests viral suppression will inadequately control inflammation and mitigate risk for progressive brain injury. We sought to quantify differences in longitudinal brain atrophy rates among older virally suppressed HIV-infected participants compared to that of healthy aging.
Methods
We examined longitudinal structural brain MRI atrophy rates employing region of interest assessments and voxel-wise tensor-based morphometry in HIV-infected participants over age 60 years (n=38) compared to age-matched HIV-uninfected healthy and cognitively normal controls (n=24).
Results
The mean age of participants was 63 years, the mean estimated duration of infection was 21 years and the median of duration of documented viral suppression was 3.2 years. Average proximal and nadir CD4 counts were 550 and 166, respectively; 15/38 (39%) met criteria for HIV-associated neurocognitive disorder. In models adjusting for age and sex, HIV serostatus was associated with more rapid average annualized rates of atrophy in the cerebellum (0.42% vs. 0.02%, p=0.016), caudate (0.74% vs. 0.03%, p=0.012), frontal lobe (0.48% vs. 0.01%, p=0.034), total cortical gray matter (0.65% vs. 0.16%, p=0.027), brain stem (0.31% vs. 0.01%, p=0.026), and pallidum (0.73% vs. 0.39%, p=0.046). Among those with HIV, atrophy rates did not differ statistically by cognitive status.
Conclusion
Despite persistent control of plasma viremia, these older HIV-infected participants demonstrate more rapid progressive brain atrophy when compared to healthy aging. Either HIV or other factors that differ between older HIV-infected participants and healthy controls could be responsible for these differences.