Getting bang for buck in the latent tuberculosis care cascade

Abstract

An important component of the strategy to reduce and eliminate tuberculosis, as outlined by WHO in their post-2015 strategy, is to target preventative therapy at those with presumed latent tuberculosis infection at high risk of future active tuberculosis. 1 Dheda K Barry 3rd, CE Maartens G Tuberculosis. Lancet. 2016; 387: 1211-1226 Summary Full Text Full Text PDF PubMed Scopus (375) Google Scholar In low-burden settings it makes sense to target some groups for screening such as close contacts of index cases with active tuberculosis, immigrants from high-burden countries, and other vulnerable subpopulations who are high risk of infection. 1 Dheda K Barry 3rd, CE Maartens G Tuberculosis. Lancet. 2016; 387: 1211-1226 Summary Full Text Full Text PDF PubMed Scopus (375) Google Scholar Indeed, reactivation of latent tuberculosis infection could account for more than 80% of incident cases in such settings. 2 Cain KP Haley CA Armstrong LR et al. Tuberculosis among foreign-born persons in the United States: achieving tuberculosis elimination. Am J Respir Crit Care Med. 2007; 175: 75-79 Crossref PubMed Scopus (112) Google Scholar By contrast, in high-burden settings, identification and treatment of infectious active tuberculosis cases remains the priority, and the sheer burden of disease and limitation of resources mean that only certain groups at high risk for progression, such as children and people with HIV, are targeted for preventative therapy. 1 Dheda K Barry 3rd, CE Maartens G Tuberculosis. Lancet. 2016; 387: 1211-1226 Summary Full Text Full Text PDF PubMed Scopus (375) Google Scholar Nevertheless, uptake of screening and preventative therapy in HIV-infected people from tuberculosis-endemic countries has been poor 3 Gupta S Granich R Date A et al. Review of policy and status of implementation of collaborative HIV-TB activities in 23 high-burden countries. Int J Tuberc Lung Dis. 2014; 18: 1149-1158 Crossref PubMed Scopus (34) Google Scholar despite recommendations that tuberculin skin testing (TST) not be a prerequisite for preventative therapy, even though it enables better targeting of treatment. 4 WHOGuidelines on the management of latent tuberculosis infection. World Health Organization, Geneva2015 Google Scholar Thus, in both high-burden and low-burden settings, targeted preventative treatment is an important strategy for tuberculosis control. However, once identified, what proportion of this target population undergo medical evaluation, are tested for latent tuberculosis, return for initiation of preventative therapy, and complete therapy; and how much attrition occurs at each step and throughout the process? The cascade of care in diagnosis and treatment of latent tuberculosis infection: a systematic review and meta-analysisWe identify major losses at several steps in the cascade of care for latent tuberculosis infection. Improvements in management of latent tuberculosis will need programmatic approaches to address the losses at each step in the cascade. Full-Text PDF