The effect of incident tuberculosis on immunological response of HIV patients on highly active anti-retroviral therapy at the university of Gondar hospital, northwest Ethiopia: a retrospective follow-up study (BMC Infectious Diseases)

Background: Human immunodeficiency virus (HIV) infection is usually complicated by high rates of tuberculosis (TB) co-infection. Impaired immune response has been reported during HIV/TB co-infection and may have significant effect on anti-retroviral therapy (ART). TB/HIV co - infection is a major public health problem in Ethiopia. Therefore, the aim of the study was to assess the effect of TB incidence on immunological response of HIV patients during ART. Methods: A retrospective follow-up study was conducted among adult HIV patients who started ART at the University of Gondar Hospital. Changes in CD4+ T - lymphocyte count and incident TB episodes occurring during 42 months of follow up on ART were assessed. Life table was used to estimate the cumulative immunologic failure. Kaplan-Meier curve was used to compare survival curves between the different categories. Cox-proportional hazard model was employed to examine predictors of immunological failure. Results: Among 400 HIV patients, 89(22.2%) were found to have immunological failure with a rate of 8.5 per 100 person-years (PY) of follow-up. Incident TB developed in 26(6.5%) of patients, with an incidence rate of 2.2 cases per 100 PY. The immunological failure rate was high (20.1/100PY) at the first year of treatment. At multivariate analysis, Cox regression analysis showed that baseline CD4+ T - cell count