Prediction of the risk of active tuberculosis in HIV-infection with an interferon-γ release assay

• Published in: The Lancet (British edition) 2013-11, Vol.382, p.S16-S16
• Main Authors: Lee, Susan Shin-Jung, Dr, Lin, Hsi-Hsun, MD, Tsai, Hung-Chin, Prof, Su, Ih-Jen, PhD, Sy, Cheng-Len, MD, Wu, Kuang-Sheng, MD, Chen, Jui-Kuang, MD, Chen, Yao-Shen, Fang, Chi-Tai, PhD
• Format: Article
• Language: English
• Subjects: adults; antiretroviral agents; blood; chest; cohort studies; cost effectiveness; death; diagnostic techniques; drugs; grants; HIV infections; interferon-gamma; Internal Medicine; men; Mycobacterium; patients; prediction; questionnaires; radiography; regression analysis; risk; risk factors; tuberculosis; vaccination; veterans; viral load
• ISSN: 0140-6736; 1474-547X
• DOI: 10.1016/S0140-6736(13)62264-3

Abstract Background Globally, tuberculosis remains the main cause of death in HIV-infected people. The spread of HIV/AIDS cannot be curbed without effective tuberculosis control strategies. Targeted treatment of latent tuberculosis infection is cost effective, but requires accurate diagnostic methods. QuantiFERON-TB Gold (QFT), an interferon-γ release assay, is promising, but its predictive value in HIV-infected patients is uncertain. We followed up a cohort of HIV-infected people to establish the incidence of tuberculosis by linking to a national tuberculosis database, and determined the predictive value of QFT. Methods We did a prospective 5-year cohort study in one medical centre and one regional hospital in Taiwan. HIV-infected adults attending outpatient clinics, from Jan 1, 2006, to Jan 31, 2010, were invited to participate after excluding active tuberculosis through absence of symptoms and a normal result of chest radiography. We used a questionnaire to obtain demographic information and information on past exposure to tuberculosis, previous tuberculosis disease, previous vaccination, HIV risk factors, CD4 cell counts, and HIV viral load testing within the past 3 months. At study entry, blood was taken for the QFT test. The cohort was followed up every 3 months, until development of active tuberculosis disease, death, or censoring on Dec 31, 2012. Cases of incident active tuberculosis were ascertained by linking participants to the national tuberculosis database registry. Patients were offered treatment if they tested positive. We used Kaplan-Meier survival analysis to explore risk factors. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios for development of incident active tuberculosis, and were adjusted for age and baseline CD4 cell count. Findings We enrolled 772 HIV-infected adults with a mean age of 36·8 years (SD 9·0), mostly men (744 [96·4%]), with a median CD4 cell count of 460 cells per μL (IQR 329–634), and a median log plasma HIV viral load of 3·40 copies per mL (IQR 1·74–3·97). HIV risk factors included being injecting drug users (517 [67%]), men who have sex with men (187 [24·2%]), and heterosexuals (62 [8%]). Almost a third (254 [32·9%]) were receiving antiretroviral treatment at study entry. Subsequently, 431 (60·3%) were placed on treatment during the study. The QFT was positive in 90 participants (11·7% [95% CI 9·5–14·0]) and indeterminate in 31 (4·0% [2·7–5·7]). 17 incident active tuberculo