A comparative study of mycobacterium tuberculosis infection in Hospitalised adult HIV infected patients with normal and abnormal renal function at the University Teaching Hospital,Lusaka

Abstract

Background Tuberculosis (TB) remains a leading cause of mortality and morbidity worldwide, including Zambia, especially among the HIV infected. Both renal dysfunction and tuberculosis have been shown to be highly prevalent among hospitalised HIV infected patients. Little is known about how TB and renal dysfunction impact each other, and whether there is any association between the occurrence of renal dysfunction and active TB infection in the HIV infected population. General Objective To determine the prevalence and determinants of active TB infection in HIV infected patients with and without kidney dysfunction. Specific Objectives To compare the proportion of active TB and identify its determinants among HIV infected patients with and without kidney dysfunction; and establish its association with kidney disease (and its severity). Methodology This was a cross – sectional, analytical study. Calculated sample size was 126 using Open EpiTM (2013). Using simple random sampling, HIV positive patients on the medical wards were recruited in two arms (with & without kidney dysfunction). Data and specimen were collected by the principle investigator and sent for analysis to respective laboratories. Data was entered onto a Microsoft office excel spread sheet, and analysed using STATA version 13. Results and Discussion A total of 133 patients (74 with renal dysfunction and 59 with normal renal function) were analysed. Microbiological TB prevalence in all HIV positive hospitalised patients was 24%, and 45% when radiological diagnosis was added. Mycobacterium tuberculosis was more prevalent in the kidney disease group at 54% compared to the non-kidney disease group at 35.59% (p=0.034). Patients in WHO stage III/IV were likely to present with TB in both groups (P=0.004, 95% CI 1.47 - 7.20). Among kidney disease patients; a higher CD4 count > 200cells/μl appears to be protective for active TB (P = 0.011, OR 0.19, 95% CI 0.05 – 0.69). Severe immunosuppression (CD4 count < 200 cells/μl) was 18.64% higher in this group (P=0.026). While, active TB was associated with evening fever (OR 2.44, 95% CI 1.00 – 5.95, P = 0.049) and male gender (OR 4.57, 95% CI 1.17 - 17.82, P = 0.029). On the other hand; renal dysfunction severity as measured by eGFR (P = 0.379); age, ART status and duration on cART, as well as history of TB contact and current viii cough, had no significant association with active TB in the kidney disease group; while Proteinuria in a TB patient was strongly associated with renal dysfunction (P < 0.001). Conclusion Patients with kidney disease are more likely to present with activeMycobacterium tuberculosis infection than other HIV infected patients. Among patients with active TB, urinalysis can help predict renal dysfunction; while determinants of active TB in the general population are not similar to those in kidney disease patients.