OPTIC-TB

The challenge

Every year, more than a million children under 15 years of age are diagnosed with tuberculosis, and at least 200,000 children die of the disease. Sub-Saharan Africa accounts for around 20% of the global burden of TB in children. 

This figure is almost certainly an underestimate, as many cases of TB in children go undiagnosed due to a combination of challenges, including diagnostic uncertainty, weak health systems, and inadequate clinical and laboratory infrastructure. Only about a third of children under 5 years of age with TB are diagnosed and treated each year, and more than 96% of deaths occur because children are not receiving adequate treatment. 

Diagnosis of TB in children is difficult because symptoms are non-specific. WHO now recommends the use of two treatment decision algorithms (TDAs), which integrate various symptoms and test results to guide physicians’ decision-making. The two TDAs are the same, except one includes X-ray results (which may not be available in all settings). However, the WHO’s recommendations were based on limited evidence.

The project

The OPTIC-TB project aims to generate additional evidence on the value of the WHO-recommended TDAs for the diagnosis of TB in children under 10 years of age. It is also gathering information on the practicalities of their implementation at primary healthcare facilities.

A cluster randomised controlled trial is being conducted in the Democratic Republic of the Congo (DRC), Tanzania and Uganda, comparing the use of the WHO’s TDAs with existing diagnostic practice. A total of 40 facilities in each country will be randomised to each arm, with 60,000 children screened across all sites. 

The trial will assess whether the use of the WHO TDAs increases the proportion of TB cases detected and the number of children who start treatment, and whether it improves treatment outcomes. It will also estimate the population-level impact of TDA use on TB disease burden, as well as its costs and cost-effectiveness. 

In addition, the project will examine the factors associated with the successful implementation of the TDAs. It will also generate data on diagnostic performance in different health system contexts across different population groups, such as malnourished children or those living with HIV. 

Impact

The OPTIC-TB project will provide key evidence on the impact of treatment decision algorithms (TDAs) to detect cases of tuberculosis in children in real-world settings. It will:

• Reveal whether the WHO-recommended TDAs improve the detection of missed cases of TB in children and reduce the burden of TB disease.
• Identify key factors associated with successful implementation to guide introductions into routine practice.
• Show whether, in real-world contexts, the TDAs are cost-effective.

A demonstration of the superiority of the TDAs compared with usual practice could greatly increase the number of children with TB who are diagnosed and receive treatment each year, reducing mortality and the community burden of TB disease.