Cognitive change over one year among older adults with HIV and a low nadir CD4 cell count

Background: Evidence regarding the risk of cognitive decline conferred by a low nadir CD4 cell count and increasing age in people living with HIV is mixed. The objective of this study was to assess the change in cognition over one year among older adults with well-controlled HIV infection and a history of low nadir CD4 cell count compared with the change in a matched non-HIV sample. Methods: We recruited 50 HIV+ aviremic individuals 40 years or older, on stable antiretroviral treatment and with a nadir CD4 < 200 cells/uL, and seventeen matched HIV-negative individuals. Neuropsychological testing was performed twice, one year apart; an NPZ was computed by averaging all z-scores and five existing algorithms for a diagnosis of HAND were applied. Change was defined as making a reliable change on the NPZ or a change in HAND category (impaired vs not). Results: Change in NPZ over one year was more often in the direction of an improvement, and not different between HIV+ and HIV- individuals. Among the HIV+, the proportion meeting criteria for HAND at baseline ranged from 34-80% depending on the classification algorithm. A reliable change in NPZ was demonstrated in a single HIV+ participant. In contrast, a transition between HAND category at one year was common. Conclusion: Among aviremic HIV+ older adults with a history of low nadir CD4 cell count, change in NPZ over 1 year was comparable to that seen among demographically matched HIV- individuals and did not represent a reliable change while transition across HAND category was common. Rates of HAND were very dependent on the classification algorithm applied. These findings provide some explanation for the inconsistent findings from existing studies and highlight the importance of exercising caution when pooling results in the field of neuroHIV. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported by the CIHR Canadian HIV Trials Network (CTNPT 005). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of MUHC Research Ethics Board gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors