Intensified Tuberculosis Case-Finding in HIV-Positive Adults Managed at Ethiopian Health Centers: Diagnostic Yield of Xpert MTB/RIF Compared with Smear Microscopy and Liquid Culture

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.

Development of an algorithm for determination of the likelihood of virological failure in HIV-positive adults receiving antiretroviral therapy in decentralized care

“…The cohort was recruited to study methods to diagnose tuberculosis and virological failure in HIV positive adults. Detailed descriptions of the cohort has been published previously [22,23]. …”

Teste rápido molecular GeneXpert MTB/RIF para diagnóstico da tuberculose

“…Balcha et al 24 , 2014 Cinco centros de saúde localizados na Etiópia O método GeneXpert obteve bons resultados, principalmente quando comparado à baciloscopia, possuindo uma alta sensibilidade em grupos de indivíduos com avançada imunossupressão. Na opinião dos autores, o teste GeneXpert deve ser utilizado como adjunto à baciloscopia e não substituí-la, como apontam outros estudos.…”

“…Nos estudos realizados por Iram et al 18 e Tortoli et al 30 , foi constatado que esse método molecular atingiu melhores resultados, podendo substituí-la. Entretanto, Balcha et al 24 e Weyer et al 40 sugeriram que o GeneXpert seja utilizado de forma adjunta à baciloscopia. Habib et al 41 relataram que, em pacientes grávidas, o GeneXpert obteve melhor sensibilidade, detectando a doença com maior rapidez, com destaque para os casos com baciloscopia negativa.…”

Increasing isoniazid preventive therapy uptake in an HIV program in rural Papua New Guinea

“…3 Studies from high-burden HIV settings have assessed the use of Xpert as a screening tool for TB in PLHIV during routine clinical evaluations and concluded that Xpert successfully detected otherwise unrecognized TB. 4,5 Isoniazid preventive therapy (IPT) is an effective strategy for preventing progression from latent tuberculous infection to active TB disease, and has been shown to reduce severe illness and mortality in HIV-infected individuals. [6][7][8][9] Despite IPT's advantages, a number of resource-limited countries have documented suboptimal IPT coverage in PLHIV, citing reasons such as stock-outs, perceived fears of poor adherence and proliferation of isoniazid (INH) resistance, a lack of local or national commitment, and perceived difficulty of ruling out active TB.…”