Abstract
BackgroundDetection of active tuberculosis (TB) before antiretroviral therapy (ART) initiation is important, but optimal diagnostic methods for use in resource-limited settings are lacking. We assessed the prevalence of TB, evaluated the diagnostic yield of Xpert MTB/RIF in comparison with smear microscopy and culture, and the impact of Xpert results on clinical management in HIV-positive adults eligible for ART at health centers in a region of Ethiopia.MethodsParticipants were prospectively recruited and followed up at 5 health centers. Trained nurses collected data on socio-demographic characteristics, medical history and symptoms, and performed physical examination. Two paired morning sputum samples were obtained, and lymph node aspirates in case of lymphadenopathy. Diagnostic yield of Xpert MTB/RIF in sputum was compared with smear microscopy and liquid culture.ResultsTB was diagnosed in 145/812 participants (17.9%), with bacteriological confirmation in 137 (16.9%). Among bacteriologically confirmed cases, 31 were smear-positive (22.6%), 96 were Xpert-positive (70.1%), and 123 were culture-positive (89.8%). Xpert MTB/RIF increased the TB detection rate by 64 cases (47.4%) compared with smear microscopy. The overall sensitivity of Xpert MTB/RIF was 66.4%, and was not significantly lower when testing one compared with two samples. While Xpert MTB/RIF was 46.7% sensitive among patients with CD4 cell counts >200 cells/mm3, this increased to 82.9% in those with CD4 cell counts ≤100 cells/mm3. Compared with Xpert-positive TB patients, Xpert-negative cases had less advanced HIV and TB disease characteristics.ConclusionsPreviously undiagnosed TB is common among HIV-positive individuals managed in Ethiopian health centers. Xpert MTB/RIF increased TB case detection, especially in patients with advanced immunosuppression. An algorithm based on the use of a single morning sputum sample for individuals with negative sputum smear microscopy could be considered for intensified case finding in patients eligible for ART. However, technical and cost-effectiveness issues relevant for low-income countries warrant further study.
Highlights
The recent achievements in mortality reduction in HIV-positive individuals through the scale up of antiretroviral therapy (ART) in sub-Saharan Africa have been dented by a high occurrence of TB, which remains the leading cause of death [1,2]
We have evaluated the diagnostic yield of Xpert MTB/RIF compared with sputum smear microscopy, using liquid culture for reference, as well as the impact of Xpert MTB/RIF testing on patient management
Tuberculosis Prevalence TB was diagnosed in 145/812 participants (17.9%); in 137 (16.9%) bacteriological confirmation was obtained
Summary
The recent achievements in mortality reduction in HIV-positive individuals through the scale up of antiretroviral therapy (ART) in sub-Saharan Africa have been dented by a high occurrence of TB, which remains the leading cause of death [1,2]. In HIV-positive individuals the performance of sputum smear microscopy is unsatisfactory; the sensitivity of this technique in HIV-positive individuals starting ART in South Africa was 22% and 26% using one and two samples, respectively [14]. Detection of active tuberculosis (TB) before antiretroviral therapy (ART) initiation is important, but optimal diagnostic methods for use in resource-limited settings are lacking. We assessed the prevalence of TB, evaluated the diagnostic yield of Xpert MTB/RIF in comparison with smear microscopy and culture, and the impact of Xpert results on clinical management in HIV-positive adults eligible for ART at health centers in a region of Ethiopia
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