The Impact of ART on TB Prevalence in a High HIV Prevalence Community

1
The Impact of ART on TB Prevalence in a High HIV
Prevalence Community

• Dr Keren Middelkoop
• Desmond Tutu HIV Centre
• Institute of Infectious Disease and Molecular
  Medicine
• University of Cape Town
• IAS Conference, Cape Town
• July 2009

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Introduction
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Study Community
Population 15 000 Single Primary Care Clinic
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ARV Program
1Zeinecker Abstract MOPED031
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Community TB data

• TB notification data
• HIV status
• Cross-Sectional TB HIV prevalence surveys
• 2005 Prior to large scale ART roll out
• 2008 Following large scale ART roll out

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Survey Methodology

• Random selection of adults gt14 years
• Clinic visit
• Early morning sputum sample
• Nebuliser-induced sputum sample
• HIV test using Orasure
• TB history, symptoms risk factors questionnaire

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Definitions of TB cases

• Current notified TB
• On TB treatment at time of survey
• Previously undiagnosed TB
• Two AFB smear ve specimens
• Two M.tb culture positive specimens
• One AFB smear ve result AND one M.tb
  culture ve result on two separate specimens.

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Results Cross Sectional Surveys
Reduction in overall TB prevalence adjusted
for age, gender HIV (p0.012)
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Pre vs Post ARV Rollout
4 participants declined HIV testing 46
participants declined HIV testing None of
those that declined had a positive TB result
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Previously Undiagnosed TB
P 0.01
P 0. 84
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Results Adult TB Notification Data
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Adult TB notification rates by HIV status
HIV positive
HIV negative
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TB notification rates in HIV pos patients
HIV positive off ART
HIV positive on ART
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Alternative explanations for decrease in
prevalence

• Changes in TB program leading to increased case
  finding
• Increased mortality
• Increased emigration

• No change in proportion of diagnosed TB in
  surveys
• In HIV neg (p0.97)
• And HIV pos (p0.24)
• No change in HIV neg TB notification rates
  (p0.16)

• Decreased TB-related mortality
• particularly in HIV pos patients

• No change in TB patients transferred out

Middelkoop Abstract CDB041
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Conclusions

• Reduction in population TB prevalence
• Predominantly due to decrease in undiagnosed TB
  in HIV pos patients
• Temporally associated with ART program
• Possible explanations
• Decreased transmission
• Decreased risk of reactivation TB in ART patients

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Acknowledgements

• Linda-Gail Bekker
• Robin Wood
• Landon Myer
• Elaine Sebastian
• Clinical team
• Groote Schuur Microbiology Laboratory
• Morna Cornell
• James McIntyre
• Robin Huebner
• NIH-CIPRA team
• All our participants

Support for this study was provided by the US
National Institute of Allergy and Infectious
Diseases (NIAID) through the Comprehensive
International Program of Research on AIDS (CIPRA)
network, Grant U19 AI53217.  The content of this
presentation does not necessarily reflect the
views or policies of NIAID, nor does mention of
trade names, commercial projects, or
organizations imply endorsement by the US
Government.