Effect of community-wide isoniazid preventive therapy on tuberculosis among South African gold miner...
Download
1 / 18

“Thibelo TB” Aurum Health Research LSHTM JHU Gold mining companies Dept. of Health, SA - PowerPoint PPT Presentation


  • 82 Views
  • Uploaded on

Effect of community-wide isoniazid preventive therapy on tuberculosis among South African gold miners. “Thibelo TB” Aurum Health Research LSHTM JHU Gold mining companies Dept. of Health, SA. Study outline.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' “Thibelo TB” Aurum Health Research LSHTM JHU Gold mining companies Dept. of Health, SA' - demetrius-price


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Effect of community-wide isoniazid preventive therapy on tuberculosis among South African gold miners

“Thibelo TB”

Aurum Health Research

LSHTM

JHU

Gold mining companies

Dept. of Health, SA


Study outline
Study outline tuberculosis among South African gold miners

  • To investigate the effect of community-wide TB preventive therapy (TBPT) in setting of high HIV prevalence (gold mines in South Africa)

  • Community randomised controlled study community-wide TBPT vs. standard TB control (targeted TBPT for high risk groups)

  • Community = mine shaft(s) and associated hostel

  • Paired design


Study outline 2
Study outline (2) tuberculosis among South African gold miners

  • Primary outcome: TB incidence measured 12 months after enrolment (over a 12 month period)

  • Secondary outcomes

    • TB incidence among HIV infected individuals, measured 12 months after enrolment (over a 12 month period)

    • TB case notifications, over the 24 month period

    • TB culture prevalence at the end of the follow-up period


Primary outcome measurement period tuberculosis among South African gold miners

9 months of TBPT

Recruitment of clusters

Prevalence survey

Enrol clusters over 15 months

  • 9 months of TBPT

  • Measure primary outcome over 12 months, from 13-24 months after enrolment


Eligibility criteria for communities
Eligibility criteria for communities tuberculosis among South African gold miners

  • Expanded DOTS program which includes

    • Active TB case finding using chest x-ray

    • Standardised monitoring and reporting

  • VCT

    • same-day confidential testing and counselling

    • Individuals found to be HIV-infected are offered referral for HIV care

  • Isoniazid and cotrimoxazole preventive therapy for HIV-infected individuals


Baseline data
Baseline data tuberculosis among South African gold miners

  • TB case notifications rates measured over the 6 month preparation phase

  • Baseline Survey (at recruitment)

    • Sampling ~ include everyone on certain days ?

    • TB and silicosis prevalence (using latest chest x-ray) measured at the time of recruitment from a random sample [n=1000 per cluster]

    • Baseline HIV prevalence (using saliva) measured at the time of recruitment from a random sample [n=1000 per cluster]


Paired versus stratified design
Paired versus stratified design? tuberculosis among South African gold miners

  • Important confounders are

    • Baseline TB case notification rates

    • Prevalence of HIV infection

    • Prevalence of silicosis

    • Baseline TB prevalence

    • Trends in the proportion of the HIV-infected workforce receiving ART over the study period

  • Paired design

    • mining company and baseline TB case rates


Sample size 1
Sample Size (1) tuberculosis among South African gold miners

  • Primary outcome: TB incidence over 12 months, measured amongst hostel dwellers

    • 90% power, type I error of 5%

    • K=0.25, paired design

    • Average community size of 2500 (80% live in hostels)

    • Factored in a potential effect of ART

    • Assumed a 60% reduction in the community wide PT arm

      Indicates 7 matched pairs


Sample size 2
Sample Size (2) tuberculosis among South African gold miners

  • Secondary outcomes:

    • 80% power, type I error of 5%, K=0.25, paired design

    • Average community size of 2500

    • Factored in a potential effect of ART

  • HIV-specific TB incidence ~ 60% reduction in the community wide PT arm (over 12 months)

  • TB case notification rates ~ 50% reduction in the community wide PT arm (over 24 months)

  • TB culture prevalence ~ 50% reduction in the community wide PT arm, based on community size of 750


Enrolment
Enrolment tuberculosis among South African gold miners

  • Intervention and control enrolment teams will work at one pair of clusters at a time

  • Both arms

    • Consent to use data

    • Baseline survey [previous x-ray for TB radiological prevalence and silicosis score; saliva sample for HIV testing]

  • Intervention arm

    • Symptom screen


Intervention 1
Intervention (1) tuberculosis among South African gold miners

  • TB screening to exclude active TB

    • using symptom questionnaire and new and previous chest x-ray

    • Investigated further if new abnormality or symptoms

  • All consenting participants offered 9 months of IPT

  • Monthly visits to

    • Dispense IPT

    • Monitoring for toxicity and side effects


Intervention 2
Intervention (2) tuberculosis among South African gold miners

  • IPT adherence enhancing measures

    • Patient education

    • Self-adherence

    • Treatment supporters

    • incentives?

  • Monitoring of adherence to IPT

    • Questionnaire (monthly); pill count etc

    • Urine testing for INH


Measuring primary outcome
Measuring primary outcome tuberculosis among South African gold miners

TB incidence measured over a 12 month period

  • Human Resources

    • List of miners living at each hostel (cluster)

    • Redundancies and death information

  • TB database

    • All TB diagnoses collected

    • Case definitions applied


Measuring secondary outcomes
Measuring secondary outcomes tuberculosis among South African gold miners

TB incidence measured over a 12 month period, amongst HIV-infected

  • As before

  • All TB diagnoses will be offered anonymous- unlinked HIV testing

  • Use the HIV prevalence from baseline survey


Measuring secondary outcomes 2
Measuring secondary outcomes (2) tuberculosis among South African gold miners

TB case notification rates over a 24 month period

  • Human Resources (info. collected every 6 mths)

    • List of miners living at each hostel (cluster)

    • Redundancies and death information

  • TB database

    • All TB diagnoses collected

  • Also calculate TB case notification in four 6 month intervals


Statistical analysis
Statistical Analysis tuberculosis among South African gold miners

Unadjusted Analysis

  • Point estimate (GM of the pairwise estimates)

    • Log(RR)=(1/c)∑log(RRj )=(1/c) ∑log(r1j /r0j)

      where r1j = TB incidence in cluster j, intervention arm and r0j = TB incidence in cluster j, control arm

    • And 95% CI

  • Paired t test, applied to the log(rates)


Statistical analysis 2
Statistical Analysis (2) tuberculosis among South African gold miners

  • Poisson regression model fitted to the individual data, including all a priori confounders and an indicator variable for matched pairs

  • Calculate the observed (Oij) and fitted (Eij) numbers of TB events for each cluster

  • Calculate the GM of Oij/Eij


Other issues
Other Issues tuberculosis among South African gold miners

  • Document TBPT use in the control arm (though the “Wellness” clinics offering care for HIV-infected individuals

  • Pilot study of quantiferon & TST to measure TB infection


ad