Cognitive reserve and neuropsychological functioning in older HIV-infected people

Progress in treatments has led to HIV+ patients getting older. Age and HIV are risk factors for neurocognitive impairment (NCI). We explored the role of cognitive reserve (CR) on cognition in a group of virologically suppressed older HIV+ people. We performed a multicenter study, consecutively enrolling asymptomatic HIV+ subjects ≥60 years old during routine outpatient visits. A comprehensive neuropsychological battery was administered. Raw test scores were adjusted based on Italian normative data and transformed into z-scores; NCI was defined according to Frascati criteria. All participants underwent the Brief Intelligence Test (TIB) and the Cognitive Reserve Index (CRI) questionnaire as proxies for CR. Relationships between TIB, CRI, and NCI were investigated by logistic or linear regression analyses. Sixty patients (85 % males, median age 66, median education 12, 10 % HCV co-infected, 25 % with past acquired immunodeficiency syndrome (AIDS)-defining events, median CD4 cells count 581 cells/μL, median nadir CD4 cells count 109 cells/μL) were enrolled. Twenty-four patients (40 %) showed Asymptomatic Neurocognitive Impairment. At logistic regression analysis, only CRI (OR 0.94; 95 % CI 0.91-0.97; P = 0.001) and TIB (OR 0.80; 95 % CI 0.71-0.90; P < 0.001) were associated with a lower risk of NCI. Higher CRI and TIB were significantly correlated with a better performance (composite z-score) both globally and at individual cognitive domains. Our findings highlight the role of CR over clinical variables in maintaining cognitive integrity in a virologically suppressed older HIV-infected population. A lifestyle characterized by experiences of mental stimulation may help to cope aging and HIV-related neurodegeneration.