Predictors of antiretroviral treatment-associated tuberculosis in Ethiopia: a nested case-control study

Abstract

Little is known about the predictors of antiretroviral treatment (ART)-associated tuberculosis (TB) in developing nations. The objective of this study was to determine predictors of ART-associated TB in adults with HIV infection at Jimma University Hospital, Ethiopia. A nested case-control study was conducted in October 2009. The study population consisted of adults with HIV infection (aged >14 years) who developed active TB in the first six months since ART initiation and controls that did not develop active TB. Data were collected using a structured and pretested questionnaire. Cox proportions hazards analysis was done to determine predictors of ART-associated TB. A total of 357 patients (119 cases and 238 controls) participated in the study. After six months of follow-up, cumulative incidence of ART-associated TB was 5.2% (123/2355). Forty (33.6%) cases were lost to follow-up after they developed ART-associated TB and 11 (9.2%) died. Fifty-one (21.4%) controls interrupted ART and 11 (4.6%) died. A CD4 lymphocyte count increase >0.5/μL/day (adjusted hazard ratio [AHR] = 19.80, 95% confidence interval [CI]: 9.52, 41.12, P < 0.001), a base-line CD4 lymphocyte count <200 cells/μL (AHR = 9.59, 95% CI: 2.36, 39.04, P = 0.002), World Health Organization (WHO) clinical stage 3 or 4 (AHR = 3.04, 95% CI: 1.62, 5.69, P < 0.001), night sweats during ART initiation (AHR = 1.53, 95% CI: 1.06, 2.21, P < 0.001) and high ART adherence (AHR = 1.30, 95% CI: 1.13, 1.50, P < 0.001) were independent predictors of ART-associated TB. HIV-infected adults with these risk factors should be followed cautiously for the development of ART-associated TB. Good ART adherence and a good immunological response during ART were associated with ART-associated TB, most likely because of an immune reconstitution inflammatory syndrome unmasking the TB.