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Original article
High prevalence of subclinical tuberculosis in HIV-1-infected persons without advanced immunodeficiency: implications for TB screening
  1. Tolu Oni1,2,
  2. Rachael Burke3,
  3. Relebohile Tsekela1,
  4. Nonzwakazi Bangani1,
  5. Ronnett Seldon1,
  6. Hannah P Gideon1,
  7. Kathryn Wood1,
  8. Katalin A Wilkinson1,4,
  9. Tom H M Ottenhoff5,
  10. Robert J Wilkinson1,2,4
  1. 1Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
  2. 2Division of Medicine, Imperial College London, London, UK
  3. 3Department of Public Health, University of Oxford, Old Road Campus, Headington, Oxford, UK
  4. 4Medical Research Council, National Institute for Medical Research, Mill Hill, London, UK
  5. 5Leiden University Medical Center, Leiden, The Netherlands
  1. Correspondence to Tolu Oni, 3.03 Wolfson Pavillion, Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa; tolullahoni{at}doctors.org.uk

Abstract

Background The prevalence of asymptomatic tuberculosis (TB) in recently diagnosed HIV-1-infected persons attending pre-antiretroviral therapy (ART) clinics is not well described. In addition, it is unclear if the detection of Mycobacterium tuberculosis in these patients clearly represents an early asymptomatic phase leading to progressive disease or transient excretion of bacilli.

Objective To describe the prevalence and outcome of subclinical TB disease in HIV-1-infected persons not eligible for ART.

Methods The study was conducted in 274 asymptomatic ART-naïve HIV-1-infected persons in Khayelitsha Day Hospital, Cape Town, South Africa. All participants were screened for TB using a symptom screen and spoligotyping was performed to determine genotypes.

Results The prevalence of subclinical TB disease was 8.5% (95% CI 5.1% to 13.0%) (n=18; median days to culture positivity 17 days), with 22% of patients being smear-positive. Spoligotyping showed a diverse variety of genotypes with all paired isolates being of the same spoligotype, effectively excluding cross-contamination. 56% of patients followed up developed symptoms 3 days to 2 months later. All were well and still in care 6–12 months after TB diagnosis; 60% were started on ART. A positive tuberculin skin test (OR 4.96, p=0.064), low CD4 count (OR 0.996, p=0.06) and number of years since HIV diagnosis (OR 1.006, p=0.056) showed trends towards predicting TB disease.

Conclusion This study found a high prevalence but good outcome (retained in care) of subclinical TB disease in HIV-1-infected persons. The results suggest that, in high HIV/TB endemic settings, a positive HIV-1 test should prompt TB screening by sputum culture irrespective of symptoms, particularly in those with a positive tuberculin skin test, longer history of HIV infection and low CD4 count. Operational difficulties in resource-constrained settings with respect to screening with TB culture highlight the need for rapid and affordable point-of-care tests to identify persons with clinical and subclinical TB disease.

  • Mycobacterium tuberculosis
  • HIV-1
  • sub-clinical tuberculosis
  • diagnosis
  • screening
  • Immunodeficiency
  • Tuberculosis

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.

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Footnotes

  • Funding RJW is funded by the Wellcome Trust (084323, 088316), MRC (UK) and the Department of Health, South Africa. KAW is funded by MRC (UK). This study was supported by the ILULU Consortium which is funded by a grant from the European Union (Sante/2006/105-061)and Bill and Melinda Gates Foundation GC#6-74 37772. The funders did not play a role in the design of the study or preparation of the manuscript.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the University of Cape Town.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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