Predictors of cognitive performance in Zambian adults with clade C HIV-1: The roles of antiretroviral therapy (ART)-induced CD4+ T-cell increase and pulmonary tuberculosis.

Objective: In this cross-sectional study in Zambia, we examined factors that influence cognitive performance in adults with clade C human immunodeficiency virus-1 (HIV) infection who were on antiretroviral therapy.

Method: We examined if detectable HIV ribonucleic acid (RNA) in blood plasma, nadir CD4+ T-cell count before antiretroviral therapy, increase in CD4+ T-cell count during antiretroviral therapy, and having pulmonary tuberculosis (TB) influenced cognitive performance. We performed a multilinear regression in which the dependent variable was the global mean cognitive T-score, an overall composite score based on 16 neuropsychological tests that were adjusted for age, sex, and education using normative data from Zambian adults without HIV infection. The 16 tests were merged into seven cognitive domains: Executive Functions, Verbal Fluency, Attention/Working Memory, Learning (immediate recall), Memory (delayed recall), Motor Control, and Speed of Information Processing.

Results: When on antiretroviral therapy, a greater increase in CD4+ T-cells was significantly associated with a better global mean cognitive T-score (p = .002). Pulmonary TB was independently associated with worse performance (p = .008). Neither nadir CD4+ T-cell count nor plasma HIV RNA during antiretroviral therapy was associated with cognitive performance.

Conclusions: Accounting for CD4+ T-cell increase after antiretroviral therapy initiation and comorbid pulmonary TB may help explain cognitive outcomes in persons with HIV infection in endemic settings. We suggest that it is essential that those with a low CD4+ T-cell count increase the number of cells as early as possible. Our data suggest that this is important for their cognitive functioning. Future research should determine whether the deleterious effect of pulmonary TB resolves after completion of TB treatment. (PsycInfo Database Record (c) 2025 APA, all rights reserved).