Aurum finds that a 40c per day preventive treatment can reduce TB cases among miners by 63%
Thibela TB, which means Prevent TB in seSotho, a predominant language among South African gold miners, is a large workplace-based study among gold miners in Gauteng, Free State and North West provinces.
Gold miners have a very high prevalence of both TB and HIV. The study, led by the Aurum Institute, aimed to examine whether isoniazid preventive therapy (IPT) given to gold miners on a community-wide basis reduced the incidence of TB.
Results from the study show that gold miners who took a daily dose of IPT for 9 months had 63% fewer cases of TB than a control group of miners who had no preventive treatment.
These results are from a population known to have the highest TB incidence in the world, with an estimated rate of 3000 to 7000 cases per 100,000.
The Thibela Study offered IPT treatment to eight mine shaft clusters of gold miners at three mining companies in South Africa over a five year period.
A further seven clusters were enrolled as control groups. More than 24,000 gold mineworkers were started on IPT, making this study the world’s largest Phase IV clinical trial of (IPT) to date.
In the case of the last clusters involved, over 78% of the workforce at 4 shafts volunteered to take part in the study – this degree of mobilization of people to take an active role in their own healthcare is unprecedented.
In addition to the evidence on the effectiveness of IPT for individuals at risk of TB, previously published findings from Aurum show that it is very safe for people to take the daily treatment – there were remarkably few adverse effects (far less than the risk of TB itself).
There was also no evidence that IPT leads to an increase in isoniazid resistance, a fear expressed by many clinicians.
Each daily dose of IPT – which comes in a single pill – costs around five US cents (40c ZAR), equivalent to $20 for a year of preventive treatment. This demonstrates that IPT is an affordable option for preventing TB in those at high risk of the disease.
The preliminary results did not show that offering IPT on a broad basis to the whole mining cluster results in a statistically significant effect in the number of incident TB cases at a population level.
However, as the study was conducted on a voluntary basis, not all miners in the community agreed to take IPT and, of those that did, not all miners took their daily treatment for the full nine months.
We look forward to sharing the full results from the study and subsequent analysis at the South African TB conference in June 2012 in Durban.
For more information contact Dr Dave Clark at Aurum on 010 590 1301.