Browsing by Author "Gupta, Ankur"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Open Access
    Prevalent and incident tuberculosis are independent risk factors for mortality among patients accessing antiretroviral therapy in South Africa
    (Public Library of Science, 2013) Gupta, Ankur; Wood, Robin; Kaplan, Richard; Bekker, Linda-Gail; Lawn, Stephen D
    BACKGROUND: Patients with prevalent or incident tuberculosis (TB) in antiretroviral treatment (ART) programmes in sub-Saharan Africa have high mortality risk. However, published data are contradictory as to whether TB is a risk factor for mortality that is independent of CD4 cell counts and other patient characteristics. Methods/FINDINGS: This observational ART cohort study was based in Cape Town, South Africa. Deaths from all causes were ascertained among patients receiving ART for up to 8 years. TB diagnoses and 4-monthly CD4 cell counts were recorded. Mortality rates were calculated and Poisson regression models were used to calculate incidence rate ratios (IRR) and identify risk factors for mortality. Of 1544 patients starting ART, 464 patients had prevalent TB at baseline and 424 developed incident TB during a median of 5.0 years follow-up. Most TB diagnoses (73.6%) were culture-confirmed. A total of 208 (13.5%) patients died during ART and mortality rates were 8.84 deaths/100 person-years during the first year of ART and decreased to 1.14 deaths/100 person-years after 5 years. In multivariate analyses adjusted for baseline and time-updated risk factors, both prevalent and incident TB were independent risk factors for mortality (IRR 1.7 [95% CI, 1.2-2.3] and 2.7 [95% CI, 1.9-3.8], respectively). Adjusted mortality risks were higher in the first 6 months of ART for those with prevalent TB at baseline (IRR 2.33; 95% CI, 1.5-3.5) and within the 6 months following diagnoses of incident TB (IRR 3.8; 95% CI, 2.6-5.7). CONCLUSIONS: Prevalent TB at baseline and incident TB during ART were strongly associated with increased mortality risk. This effect was time-dependent, suggesting that TB and mortality are likely to be causally related and that TB is not simply an epiphenomenon among highly immunocompromised patients. Strategies to rapidly diagnose, treat and prevent TB prior to and during ART urgently need to be implemented.
  • Thumbnail Image
    Item
    Open Access
    The proportions of people living with HIV in low and middle-income countries who test tuberculin skin test positive using either a 5mm or a 10mm cut-off: a systematic review
    (BioMed Central Ltd, 2013) Kerkhoff, Andrew; Gupta, Ankur; Samandari, Taraz; Lawn, Stephen
    BACKGROUND:A positive tuberculin skin test (TST) is often defined by skin induration of [greater than or equal to]10mm in people who are HIV-seronegative. However, to increase sensitivity for detection of Mycobacterium tuberculosis infection in the context of impaired immune function, a revised cut-off of [greater than or equal to]5mm is used for people living with HIV infection. The incremental proportion of patients who are included by this revised definition and the association between this proportion and CD4+ cell count are unknown. METHODS: The literature was systematically reviewed to determine the proportion of people living with HIV (PLWH) without evidence of active tuberculosis in low and middle-income countries who tested TST-positive using cut-offs of [greater than or equal to]5mm and [greater than or equal to]10mm of induration. The difference in the proportion testing TST-positive using the two cut-off sizes was calculated for all eligible studies and was stratified by geographical region and CD4+ cell count. RESULTS: A total of 32 studies identified meeting criteria were identified, providing data on 10,971 PLWH from sub-Saharan Africa, Asia and the Americas. The median proportion of PLWH testing TST-positive using a cut-off of [greater than or equal to]5mm was 26.8% (IQR, 19.8-46.1%; range, 2.5-81.0%). Using a cut-off of [greater than or equal to]10mm, the median proportion of PLWH testing TST-positive was 19.6% (IQR, 13.7-36.8%; range 0-52.1%). The median difference in the proportion of PLWH testing TST-positive using the two cut-offs was 6.0% (IQR, 3.4-10.1%; range, 0-37.6%). Among those with CD4+ cell counts of <200, 200-499 and [greater than or equal to]500 cells/muL, the proportion of positive tests defined by the [greater than or equal to]5mm cut-off that were between 5.0 and 9.9mm in diameter was similar (12.5%, 12.9% and 10.5%, respectively). CONCLUSIONS: There is a small incremental yield in the proportion of PLWH who test TST-positive when using an induration cut-off size of [greater than or equal to]5mm compared to [greater than or equal to]10mm. This proportion was similar across the range of CD4+ cell strata, supporting the current standardization of this cut-off at all levels of immunodeficiency.