Low levels of treatment adherence and success lead to unacceptably poor outcomes for patients with drug-resistant (DR) tuberculosis. There is increasing interest in the use of treatment adherence technologies to provide additional support to TB patients, with some evidence of impact. An additional benefit of this patient-centred approach is the potential of reducing costs, for both the patient and health system provider, through the reduced clinic visits required. These technologies can also be used to prioritise those patients at higher risk of poor treatment outcomes, following a differentiated care approach.

1. Project objectives
   The aim of this research will be to explore evidence on the economic and epidemiological impact of adherence technologies, particularly its AMR-related added value (the impact and economic value of DR-related health outcomes) in a transmission model framework. The objectives will be
   • to review the literature to collate evidence on the impact of adherence technology interventions on health outcomes for DR-TB and the impact of non-adherence on resistance acquisition, as well as collating cost data from the Value TB project (held at LSHTM),
   • to create a country-level epidemiological model of TB transmission with a focus on DR-TB burden, parameterised for Ethiopia, adapting a standard compartmental TB transmission model as a basis. The model will need to be augmented to simultaneously consider programmatic and transmission related pathways. For instance, the model will be extended to include an expanded DR-TB treatment pathway, to allow for the consideration of adherence technologies and their effect, as well as resistance acquisition. At the same time, it will be important to model heterogeneity in patient risk of non-adherence in this context, in order to consider the importance of differentiated care.
   • to integrate a cost model into the transmission framework to analyse the population impact, cost and cost-effectiveness of the adherence technology. This model will be used to explore the AMR-related added value of the intervention. This integration of transmission and economic models is important to avoid undervaluing interventions, where there has been no previous economic evaluation in TB highlighting the added value of new technologies from an AMR perspective. The student will conduct a cost-effectiveness analysis to consider the value of reductions in both transmission as well as further resistance acquisition and the costs associated, such as the need to develop new antibiotics. This is likely to have additional complications due to issues such as bystander effects, which consider the impact of antibiotic treatment of bacterial species not specifically being targeted (e.g. the overlap between fluroquinolone use for MDR-TB and pneumonia).
2. Techniques to be used
   Mathematical modelling and economic evaluation
3. Confirmed availability of databases
   No databases will be required, however data from a related project (see iCASE below) will be used to supplement the project.
4. Risks to the project
   These include insufficient data on DR-TB adherence interventions (mitigated by the use of a simpler model which can use cope with weaker data, albeit with more uncertainty), and insufficient data on costs for Ethiopia (mitigated by the potential for replacement with a country with better data)