Low Rates of Neurocognitive Impairment Are Observed in Neuro-Asymptomatic HIV-Infected Subjects on Effective Antiretroviral Therapy

Background: Few studies investigating the rate of neurocognitive (NC) impairment in effectively treated neuro-asymptomatic HIV-infected subjects have been performed. Methods: We assessed NC function via a computerized cognitive test in HIV-infected subjects on stable combination antiretroviral therapy (cART) with plasma HIV RNA <50 copies/mL for at least 3 months. Neurologically symptomatic subjects were excluded. Current cART was evaluated for drug class (protease inhibitor [PI] vs non-nucleoside reverse transcriptase inhibitor [NNRTI] based) and Clinical Penetration Effectiveness (CPE) score. NC impairment was defined as a NC domain score >1 SD below mean age-matched population scores in at least 2 cognitive domains and global NC composite z-score calculated. Associations between NC scores and clinical parameters were evaluated using linear regression. Results: 101(88% male) subjects participated. Median (IQR) age was 53 (43-62) years, with current CD4+ 525 (373-710) and nadir CD4+ 185 (83-260) cells/mu L. 25 subjects (25%) had chronic hepatitis C. Median (IQR) CPE score was 1.5 (1.5-2.5), and 53% were receiving NNRTI-based cART. Overall 19 (19%) subjects had NC impairment. No association between presence of NC impairment and clinical parameters were observed (P > .14, all values). Poorer global NC composite z-score was independently associated with lower nadir CD4+ lymphocyte count (P = .04) and older age (P < .001) but not other study parameters (P > .10 all values). Conclusion: In neuro-asymptomatic HIV-infected adults on stable cART, rates of NC impairment are low. HIV disease status (lower nadir CD4+ count) and older age, but not CPE score or cART drug class, are associated with poorer NC performance.