Abstract Body

A major concern for people living with HIV is the reportedly high prevalence of cognitive impairment, which may reflect an exacerbation of the effects of ageing on the brain. Using longitudinal neuroimaging and neuropsychological data from participants in the EU-funded COBRA collaboration, we determined whether successfully treated HIV infection is associated with accelerated age-related changes to brain structure and function.

HIV+ve people with plasma HIV RNA <50 copies/ml on antiretroviral therapy for >1 year and demographically comparable HIV-ve controls were recruited at centres in Amsterdam and London. Participants were assessed at baseline and two years using multi-modal magnetic resonance imaging (T1-weighted, diffusion, resting-state fMRI, arterial spin labelling, spectroscopy), processed to generate global and regional summary metrics of brain structure and function. Neuropsychological assessments (reported as domain T-scores adjusted for age, sex, education) tested the cognitive domains of attention, executive function, language, memory, motor function and processing speed. Between-group comparisons of baseline values and change over time were assessed using linear and mixed-effects regression respectively, with models accounting for age, time between assessments and (for neuroimaging only) intracranial volume and scanner type.

At baseline, the 134 HIV+ve people (mean age 57.4 [SD=7.4] years, 6.7% female) had smaller grey matter volume, abnormal white matter microstructure and poorer cognitive function compared to 79 HIV-ve controls (58.8 [7.8] years, 7.6% female). Age-related declines in neuroimaging measures were observed in both groups, e.g., HIV+ve people lost 0.82% of brain volume per year, while HIV-ve controls lost 0.77%. Importantly, there were no group differences in the rates of brain volume loss or change in any neuroimaging measure (p>0.1, Table). Measure of cognitive function showed limited change. In fact global cognition T-score increased in both groups (HIV+ve 0.79, HIV-ve 0.45). There were no group differences in rates of change in cognition (p>0.1), with the exception of attention T-score, where the groups became more similar.

While HIV+ve persons had abnormal measures of brain structure and function at baseline, we found no difference in the dynamics of these measures over time between HIV+ve and HIV-ve persons. Our findings suggest that there is no evidence for accelerated brain ageing in successfully treated HIV+ve people.