The cascade-of-care for tuberculosis infection in low-incidence countries – a scoping review protocol
The purpose of this scoping review is to describe and summarise the rationale behind and methodological approaches used to conduct cascade-of-care analyses for TB infection in low-TB incidence countries.
Executive summary
Ending tuberculosis (TB) by 2030 is one of the targets outlined in the Sustainable Development Goals. To achieve this goal it is necessary to implement a comprehensive strategy, including several interventions to prevent, diagnose and treat TB in a timely and effective manner. Among these interventions, management of TB infection is considered essential.
TB infection, also known as latent TB infection (LTBI), is defined as ‘a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens with no evidence of clinically manifest active TB'. People with TB infection have no signs or symptoms of TB and are considered to be at risk of progressing to TB disease. TB preventive treatment should be offered to those who have been exposed to TB or who are infected with TB to avoid progression to active TB disease.
Approximately one-fourth of the world’s population is infected with TB. In Europe alone, the prevalence of TB infection has been estimated at between 11 and 15%. Delivering systematic screening of TB infection in at-risk populations and provision of TB preventive treatment are key components of the global TB elimination strategy, particularly in countries with low TB incidence (i.e. with a notification rate <10 TB cases per 100 000 population). A majority of the Member States of the European Union (EU) and European Economic Area (EEA) have a low TB incidence.
Rationale
The management of TB infection involves the sequential implementation of key interventions, a process that has been labelled as cascade-of-care. The concept cascade-of-care (or continuum of care), is also an analytical framework used to evaluate public health interventions by constructing models of the proportion of people completing sequential steps of care for a given condition or disease.
Cascade-of-care analyses have been applied to both TB disease and TB infection. For the latter, systematic and scoping reviews have focussed on specific at-risk populations and/or settings with high-TB burden. So far, information on data sources and analytical decisions on how to conduct cascade-of-care analyses for TB infection have not been mapped in sufficient detail, as has been done for other diseases. In an exploratory search conducted in August 2023 there were no ongoing systematic or scoping reviews identified on this topic in three open-access repositories (PROSPERO, OSF Registries and Figshare).
The purpose of this scoping review will therefore be to describe and summarise the rationale behind and methodological approaches used to conduct cascade-of-care analyses for TB infection in low-TB incidence countries. Knowledge users, defined as ‘those who have a vested interest in the research, its outcomes and impacts’, will be involved throughout the review process, including the identification of relevant publications and the discussion of findings to inform surveillance and monitoring strategies for TB infection at national and regional levels in the EU/EEA.
