Pulmonary Tuberculosis as a comorbid condtion in HIV positive adults and its effects on Neuro-cognitive function in Zambia

Abstract

Objective: The objective of the study was to explore the effects of PTB as a co-morbid condition in HIV+ adults on neurocognitive functions.Rationale: The study will help in understanding the impact and effects of pulmonary tuberculosis (PTB) on the HIV+ Zambian adults and how far it affects the neurocognitive functions. The study will also help in determining implications for treatment, adherence and use of CNS penetrating antiretroviral, anti-TB regimens, rehabilitation programmes, Human resource replacements at work and care. It will help clinicians determining as when to start treatment to protect the CNS from damage and promote continued quality of life/productivity over the lifespan. Methods: The study was conducted in Lusaka urban clinics: Kalingalinga, Matero Main, Matero Referral Centre, Kabwata, Chipata and Chilenje clinics respectively. This was a cross- sectional study, which was both retrospective and prospective case-control that reviewed medical files of clients. 324 medical patients were enrolled.PTB+/HIV+ and PTB-/HIV+ groups were statistically compared in terms of cognitive profiles, biomarkers (current CD4 count and viral load) and current WHO HIV disease staging.Results: Out of 324, only 243 were studied. Results indicated significant neurocognitive impairment in PTB+/HIV+ group than PTB-/HIV+ , p<.001, by using GDS ≥ 0.50, 56% of PTB+ were globally impaired compared to 32% non PTB. The mean CD4 count for PTB+ was 325 cells/µl compared to 512 cells//µl for non PTB. The PTB+/HIV+ CD4 count was in the range 201-499 cells//µl, whereas the non PTB had above 500 cells//µl. 95% of PTB+ were stages 3 and 4, whereas 95% of non PTB were stage 1. 69% of PTB+ had viral-load detected whereas the non PTB had 15%. Linear regression model (p<.01), PTB status was predictive of global deficit score even while accounting for demographic and medical variables that have previously been associated with neurocognitive impairments. Specifically, a linear regression model identified PTB status (F=6.26, p < .02) as a significant predictor of Global Deficit Score (GDS). Current CD4 count (F =3.21, p <.08), viral load detection (F =0.54), current WHO stage (F=1.41), were not significant independent predictors of GDS (all ps > .10). Conclusion: This could be one of the first studies to highlight the fact that there is an association between PTB and neurocognitve impairment in HIV+ adult individuals. Findings of the present study show the presence of neuropsychological impairments in all the domains except motor in the PTB+/HIV+ adults in Zambia. Results indicate that there are lower biomarkers, WHO HIV stage and more global impairments in the PTB+/HIV+ than the PTB-/HIV+.