The impact of Isoniazid Preventive Therapy (IPT) on tuberculosis incidence among HIV infected patients in Addis Ababa, Ethiopia

Abstract

Background: IPT is an effective, safe and feasible disease prevention scheme that should be administered for all PLHIV living in areas with high latent TB prevalence. Objective: To assess the impact of isoniazid in the incidence of tuberculosis among HIV infected individuals in Addis Ababa. Methods: A case control study design was undertaken among 489 HIV and TB infected patients in Addis Ababa from January 2008 to December 2010. Results: Tuberculosis incidence rate among those who developed TB after completing 6-9 month isoniazid preventative therapy was17.14 PYO compared to 10.28 PYO among those who were not. Isonizide reduced the chance of developing tuberculosis among HIV infected patients (OR= 0.072; 95% CI 0.044, 0.12). Age (AOR= 0.14; 95% CI 0.03, 0.97) and sex (AOR= 1.86; 95% CI 1.02, 2.23) of the patient, CD4 count at HIV diagnosis (AOR= 0.21; 95% CI 0.13, 0.31), clinical stage of HIV illness (AOR= 1.22; 95% CI 1.09, 1.84) and past tuberculosis history (AOR = 1.97; 95% CI 1.24, 3.67) were major factors associated with tuberculosis incidence. Conclusions: INH prophylaxis was associated with lower incidence of tuberculosis among PLHIV.