The effect of pulmonary tuberculosis on neurocognitive function in HIV infected adult patients in Lusaka, Zambia

Abstract

Objective: To explore the effects of Pulmonary Tuberculosis on neurocognitive functions in HIV+ adults in Lusaka, Zambia.

Materials and methods: In a retrospective and prospective case-control study, Global Deficit Score (GDS) was used as an overall measure for cognitive impairments between groups and also within the PTB+/HIV+ group, and Domain Deficit Scores (DDS) were used to summarize cognitive impairments within each of the seven domains. To examine group differences in neurocognitive status, we used Wilcoxon ranked sum tests to compare the performance between groups on neuropsychological test battery.

Results: Out of 324, only 244 were studied. Results indicated significant neurocognitive impairment in PTB+/HIV+ group than PTB-/HIV+ in the GDS, p<.001, significant lower CD4 cell count with a mean of 323 cells/μl compared to 510 cells//μl for the control group. The PTB+/HIV+ group, CD4 cell count was in the range 201-499 cells//μl compared to their cohort CD4 cell count above 500 cells//μl indicating immune compromise in the PTB+/HIV+. 95% of PTB+ were stages 3 and 4 indicating AIDS defining stage, whereas 95% of PTB negative were stage 1 suggesting immunocompetent. Linear regression model (p<.01), PTB status was predictive of GDS 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). Age (F =3.21, p <.08) approached significance, while years of schooling (F =0.54), current WHO stage (F=1.41) and gender (F= .13) were not significant independent predictors of GDS (all ps > .10).

Conclusion: This study highlights the fact that PTB has neurocognitve impairment in HIV+ adult individuals. Findings of the present study show the presence of neuropsychological impairments in all the seven domains except motor in the PTB+/HIV+ adults in Lusaka district, Zambia.