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Widespread ART is associated with decline in TB prevalence
Presented by Keren Middelkoop (South Africa), Keren Middelkoop (South Africa).
K. Middelkoop1, R. Wood1, L. Myer2,3, A. Whitelaw4,5, G. Kaplan6, J. McIntyre7, L.-G. Bekker1
1University of Cape Town, Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Department of Medicine, Cape Town, South Africa, 2University of Cape Town, Infectious Diseases Epidemiology Unit, School of Public Health & Family Medicine, Cape Town, South Africa, 3Columbia University, Department of Epidemiology, Mailman School of Public Health, New York, United States, 4University of Cape Town, Division of Medical Microbiology, Department of Clinical Laboratory Sciences, Cape Town, South Africa, 5National Health Laboratory Service, Cape Town, South Africa, 6University of Medicine and Dentistry of New Jersey, Laboratory of Mycobacterial Immunity and Pathogenesis, The Public Health Research Institute, New Jersey, United States, 7University of the Witwatersrand, Perinatal HIV Research Unit, Johannesburg, South Africa
Background: The HIV epidemic is driving tuberculosis (TB) epidemics to alarming incidence and prevalence rates in sub-Saharan Africa. There are few data describing the impact of antiretroviral therapy (ART) on TB prevalence rates. In 2005 we reported a high prevalence of undiagnosed TB prior to large-scale ART availability, in a community with high HIV prevalence. HIV-infected individuals had a higher proportion of undiagnosed TB compared to HIV-uninfected.
Methods: In 2008 we performed a follow-up cross-sectional prevalence survey, with similar methodology as the 2005 study. A random population sample was enrolled, two sputum specimens were obtained from each participant (1 early morning and 1 saline nebulised sputum specimen), and a TB history questionnaire was completed. Oral transudate was collected for anonymous, linked HIV testing. Undiagnosed TB was defined as 2 positive smear results, or two positive cultures of Mycobaterium tuberculosis.
Results: By end 2008, 31% of HIV-infected patients were receiving ART. The mean age of the 1259 partiicpants was 29 years (range: 15-78); 49% were female. HIV prevalence was 25%.
| | HIV+ve | HIV-ve | | | 2005 | 2008 | | 2005 | 2008 | | | | n=174 | n=310 | p-value | n=584 | n=949 | p-value | | On treatment TB (%) | 4.0% | 1.3% | 0.188 | 0.7% | 1.2% | 0.997 | | Undiagnosed TB (%) | 5.2% | 1.6% | 0.008 | 0.5% | 0.8% | 0.703 | | TOTAL | 9.2% | 2.9% | 0.005 | 1.2% | 2.0% | 0.810 |
After adjusting for variation in participant age, sex and HIV status, the overall 2008 prevalence was significantly lower than the overall 2005 prevalence (p=0.02). This decrease is driven by the HIV-infected population, with the most significant decrease noted in undiagnosed TB in HIV-infected participant.
Conclusions: Wide-scale availability of ART appears to be associated with a decrease in prevalence of microbiologically confirmed TB in this community, predominantly in the HIV-infected population.
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