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
- sub-clinical tuberculosis
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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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