Cross Border Referral Of Mine Workers On TB Treatment In Southern Africa

Name of Project/Study:  Development and evaluation of an intervention to improve adherence to TB treatment among mineworkers in Southern Africa
Duration of Project/Study: 8 months
Start of Project/Study Year/Month: 1 November 2015 – 30 June 2016


South Africa has one of the largest TB disease burdens globally, with 1 in 100 people contracting TB every year. Mineworkers are especially susceptible to TB and HIV infection due to a complex mix of factors that elevate their risk of contagion, infection, and disease progression. Gold mineworkers working in South Africa have one of the highest TB incidence rates in the world, currently estimated at 3,000 per100 000 population (Churchyard et al., 2014) and co-infection with HIV remains high. An average of 3,500 TB cases is reported among mineworkers each year in South Africa. Furthermore, estimates suggest that mineworkers may have poorer health outcomes and higher mortality rates related to these conditions compared to the general population.

South Africa is recognized as a world leader in the mining industry, with a valuable concentration of raw materials including platinum, gold and diamonds. This industry attracts mineworkers from across the Southern African Development Community (SADC) as well as from all provinces throughout the country. More than 100,000 workers in the mining industry come from Lesotho, Swaziland, Mozambique, or Botswana, and approximately 80 percent are concentrated in the gold mining industry.

Despite the longstanding history of cross-border migration for the purposes of labour-sending, few regional policies and systems have been implemented to limit the spread of communicable diseases such as TB and HIV and provide continuity of care and support for mineworkers, ex-mineworkers, and their families upon return home. The financial cost and health system burden to labour-sending countries is substantial. Migrant labourers can often face treatment interruptions, inadequate referral systems, and less resourced care facilities when returning home, which can lead to treatment failure, TB relapse, and poorer health outcomes.

Given South African gold mines’ strong reliance on migrant labourers from outside of South Africa, addressing TB requires a joint effort from the SADC. The World Bank, as part of a strategy to respond to this epidemic, is supporting an initiative to harmonize sub-regional action to reverse decades of inaction on TB in the mining sector and provide a valuable proof of concept from which knowledge and good solutions will emerge.

Project Aim

This project, as part of the World Bank’s initiative to combat TB in the mining sector, sought to develop and evaluate the effeteness of a comprehensive intervention designed to support mineworkers on TB treatment from Southern Africa. The project involved three phases as follows:

  1. Elicitation Research (Phase 1)
  2. Intervention Study (Phase 2)
  3. Cost Consequence Analysis (Phase 3)

Phase 1 of this project identified key individual informational, motivational and behavioural (IMB) deficits as well as structural barriers to adherence to TB treatment and care for mineworkers with TB in two gold mines in South Africa. The activities to achieve this included a desktop review, elicitation research with relevant stakeholders, and a quantitative evaluation of the experiences of mineworkers with TB who had participated in previous interventions or had recently returned from a SADC country after holiday leave 2015. Methodology included online and paper-based surveys, structured interviews, and focus group discussions. Phase 1 findings formed the basis for the development of an intervention to be implemented and evaluated in Phase 2.

Phase 2 involved a randomized controlled study (RCT) which sought to assess whether a multi-level and context-specific intervention involving a client-centred component (framed on an Information–Motivation–Behavioural (IMB) Skill model), and a package of systems interventions, would improve adherence to TB treatment, retention into care, TB knowledge, TB stigma and select clinical outcomes

Phase 3 of the project consisted of a Cost-Consequence analysis. This exercise sought to generate information that can assist future implementers of the interventions similar to the one implemented in Phase 2, to understand the cost of the intervention and the consequences thereof in terms of outcomes.

Key Findings

  • The elicitation research using multiple research methodologies led to the development of a multi-faceted, evidence-based intervention package, which directly spoke to the needs of mineworkers with TB. Various barriers to TB treatment adherence were assessed and targeted in the intervention design, content and approach.
  • Overall, intervention participants attained better overall adherence, weekend adherence and week-day adherence compared to control participants. Based on the Average treatment effect (ATE) estimates, on average, participants who benefited from the intervention attained a statistically higher overall adherence, weekend adherence, and week-day adherence, compared to their counterparts in the control group. The mean difference for these scores between the two groups was statistically significant (p=0.015, p=0.005, p=0.013 respectively). However, the average treatment effect was not statistically significant in respect of Easter-break adherence (p=0.184 for mean difference).
  • The risk of defaulting TB treatment was delayed for intervention participants vs. control in both mining companies. The Kaplan-Meier survival estimates and log-rank test of equality of failure functions revealed that the intervention had an impact on reducing time to defaulting TB treatment and the overall impact was statistically significant (p=0.023)
  • Certain factors were found to be associated with the impact of the study intervention. The heterogeneous impact evaluation revealed that study group, DR-TB comorbidity, and Site of current TB, were significantly associated with the impact of the study intervention. As shown earlier, participants in the intervention group seem to have had better adherences compared to their counterparts in the control group (p=0.009). Not having DR-TB comorbidity increased the intervention’s effect by 36 adherence units (p=0.033), whereas having extra-pulmonary TB decreased the impact of the intervention by 24 adherence units (p=0.017). Although not statistically significant, being HIV positive, living with some with TB, and having no education seemed to not favour the effect of the intervention on overall adherence. On the other hand, not having NCD and silicosis comorbidity, and having had TB infection before favoured the effect of the intervention.
  • The analysis suggests that the intervention effects were more pronounced for those with lower adherence, suggesting the intervention worked best for those who needed it most. The quantile regression estimates indicated that the intervention had a statistically significant effect on the 25th percentile of the adherence distribution. It increased the 25th percentile of the outcome variable by 23% (p=0.018) and the median (50th percentile) by 22% (p=0.031) but not at any higher percentile.
  • Participants in the intervention arm trended toward higher gains in perceived psychosocial support scores and TB knowledge, as well as less stigma.  The Mixed effect modelling revealed that on average, the perceived psychosocial support scores (%) increased from baseline to endpoint for both the control and intervention groups. However, the participants in the intervention group experienced a much higher increase compared to those in the control group, even though this difference was not statistically significant at 95% significance level. With respect to the composite TB knowledge score (%), again on average participants in the intervention and control groups gained knowledge around TB during the study period.  However, the gain in the intervention group from baseline to end-point was significantly greater compared to the gain in the control group. The same direction and magnitude of impact was estimated for the composite stigma index score, but the differences in change between the two study arms was not statistically significant. Thus, a positive trend was achieved in the intervention group for psychosocial support, less stigma and knowledge level gains for the intervention arm. In addition, the intervention had no significant impact on weight gain.

Donors: Funded by Aquity Innovations (formerly University Research South Africa), sponsored by the World Bank, in partnership with the Sibanye Gold and Harmony mines.

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