Methodological considerations for economic modelling of latent tuberculous infection screening in migrants

Tuberculosis (TB) in migrants from endemic to low-incidence countries results mainly from the reactivation of latent tuberculous infection (LTBI). LTBI screening policies for migrants vary greatly between countries, and the evidence on the cost-effectiveness of the different approaches is weak and heterogeneous. The aim of this review was to assess the methodology used in published economic evaluations of LTBI screening among migrants to identify critical methodological options that must be considered when using modelling to determine value for money from different economic perspectives. Three electronic databases were searched and 10 articles were included. There was considerable variation across this small number of studies with regard to economic perspective, main outcomes, modelling technique, screening options and target populations considered, as well as in parameterisation of the epidemiological situation, test accuracy, efficacy, safety and programme performance. Only one study adopted a societal perspective; others adopted a health care or wider government perspective. Parameters representing the cascade of screening and treating LTBI varied widely, with some studies using highly aspirational scenarios. This review emphasises the need for a more harmonised approach for economic analysis, and better transparency in how policy options and economic perspectives influence methodological choices. Variability is justifiable for some parameters. However, sufficient data are available to standardise others. A societal perspective is ideal, but can be challenging due to limited data. Assumptions about programme performance should be based on empirical data or at least realistic assumptions. Results should be interpreted within specific contexts and policy options, with cautious generalisations.