Identifying Neurocognitive Decline at 36 Months among HIV-Positive Participants in the CHARTER Cohort Using Group-Based Trajectory Analysis
The CHARTER study is a large study conducted in the US that aimed to determine how central and peripheral nervous system complications of HIV are affected by different histories and regimens of antiretroviral therapy (ART). In this secondary analysis of the CHARTER data, researchers studied the changes in cognitive abilities (thinking and memory) of people with HIV over a 3-year period. Performance on each neuropsychological test was modelled to identify
groups of people who showed a similar pattern to performance over time. Interestingly, they didn’t use typical comparisons to norms for identifying decline, but rather relied on the raw scores. They found that only a small group of participants showed cognitive decline, mostly in motor skills and executive functions. This study sheds light on how cognitive abilities change in HIV-positive individuals and introduces a new analytical approach to studying these changes. However, more research is needed to understand the clinical significance and reasons behind these cognitive changes.
While HIV-associated neurocognitive impairment remains common despite the widespread use of combined antiretroviral therapy (cART), there have been relatively few studies investigating the trajectories of neurocognitive change in longitudinal NeuroAIDS studies.
To estimate the magnitude and pattern of neurocognitive change over the first 3 years of follow-up using Group-Based Trajectory Analysis (GBTA) applied to participants in the longitudinal arm of the CHARTER cohort.
The study population consisted of 701 CHARTER participants who underwent neuropsychological (NP) testing on at least 2 occasions. Raw test scores on 15 NP measures were modeled using GBTA. Each trajectory was categorized as stable, improved or declined, according to two different criteria for change (whether the magnitude of the estimated change at 36 months differed ≥ 0.5 standard deviations from baseline value or changed by > the standard error of measurement estimated at times 1 and 2). Individuals who declined on one or more NP measures were categorized as decliners.
Overall, 111 individuals (15.8%) declined on at least one NP test over 36 months, with the vast majority showing decline on a single NP test (93/111-83.8%). The posterior probability of group assignment was high in most participants (71%) after only 2 sessions, and in the overwhelming majority of those with 3+ sessions. Heterogeneity of trajectories was the norm rather than the exception. Individuals who declined had, on average, worse baseline NP performance on every test, were older, had a longer duration of HIV infection and more follow-up sessions.
The present study identified heterogeneous trajectories over 3 years across 15 NP raw test scores using GBTA. Cognitive decline was observed in only a small subset of this study cohort. Decliners had demographics and HIV characteristics that have been previously associated with cognitive decline, suggesting clinical validity for the method.