Thibela TB
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Gauteng, North West and Free State Provinces, South Africa
Thibela TB, which stands for Prevent TB in Sotho, a predominant language among South African gold miners, is a large community-based study among gold miners in Gauteng, Free State and North West provinces in South Africa. Gold miners have a very high prevalence of both TB and HIV. The aim of the study is to examine whether isoniazid prophylaxis therapy given to gold-miners on a community-wide basis reduces the incidence of TB.
It is a cluster randomized trial, meaning the communities of gold miners are being randomized to receive either nine months of IPT, or the usual standard of care for TB.
Inclusion in the study
Since the primary endpoint was to decrease the incidence of TB in the community where gold mining took place, both gold miners, mine staff were given the option of receiving IPT.
Exclusion Criteria
As Thibela was investigational, it employed rigorous exclusion criteria, including
- Active or confirmed TB;
- Weight less than 40 kg;
- Hypersensitivity to IPT;
- Chronic liver disease or alcoholism (defined by the FAST criteria)*;
- History of convulsions or psychosis;
- Peripheral neuropathy**;
- Women of child bearing age who are not using contraception;
- Concomitant medication with phenytoin, carbamazepine, warfarin or theophylline;
- Participation in other investigational studies within 3 months.
Community Mobilization and Education Strategies
The recruitment of study participants involved a community mobilization and education campaign that began several weeks before recruitment into the study. The campaign involved training peer educators, distributing educational materials using cartoon characters, conducting dramas using well-known actors, and broadcasting information into the mines through a radio campaign.
The mine shafts were aggregated into clusters and the community mobilization began at the same time throughout a cluster.
Screening for active TB. A symptom questionnaire and chest x-ray was used to screen miners for active TB prior to starting IPT. Symptoms were cough, night sweats and weight loss. Tuberculin Skin Tests were not used. If miners had a positive symptom screen or abnormal chest x-ray, they were investigated further for TB with sputum microscopy and culture.
Retention and Adherence
In the early study clusters there was a drop in retention to the study. An analysis revealed a sharp drop-off in the first month. Tracking of participants who did not keep their first appointment greatly increased the retention rate. In the later clusters, the adherence rose to over 85%, and 92% participants who kept their appointments reported missing no doses of IPT in the past 3 days. Analysis of other measures of adherence is ongoing.
Experience with IPT
The primary study outcome (decreased community TB incidence) is pending, but there are many important findings to date. Over 27,000 miners and employers enrolled in the study; 88% were eligible for IPT and 98% started IPT. Among the 23,558 participants who started IPT, there were 126 adverse events (0.005); most were graded as mild (66%) or moderate (31%).
Screening for TB before implementing IPT is an effective method of conducting intensified case finding for TB among a high risk community. The majority of new cases of tuberculosis in the mines were found when screening before IPT implementation.
Working within an occupational health structure
The involvement of constituent’s stakeholders has been key to the success of the program. The investigators met with the South Africa Department of Heath, organized labor, unions and mineworkers health and safety committees. They engaged with them long before implementing the study and continued to meet with them throughout the study. They identified leaders among the miners and developed advisory boards to assist them and to serve as the “ear piece” for clarifying and dispelling rumors and for educating participants.
*FAST Screening Tool: http://alcoholism.about.com/od/tests/a/fast.htm
** Defined as sensory alteration or paresthesia causing greater than minimal interference with usual social and functional activities
Below you can see abstracts and publications from the Thibela Study.
