Global burden of tuberculosis: where we are and what to do
Authors: Martin P Grobusch, Nathan Kapata
Journal: The Lancet Infectious Diseases (2018)

Tuberculosis continues to cause ill health and deaths across many populations in the world, 25 years since WHO declared the disease a global emergency.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar, 2WHO Global Tuberculosis ProgrammeTB: a global emergency, WHO report on the TB epidemic. World Health Organization, Geneva1994http://www.who.int/iris/handle/10665/58749Date accessed: October 23, 2018Google Scholar In The Lancet Infectious Diseases, the Global Burden of Disease (GBD) Tuberculosis Collaborators report the burden of tuberculosis in 2016 and trends since 1990.3GBD Tuberculosis CollaboratorsGlobal, regional, and national burden of tuberculosis from 1990 to 2016: results from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 Study.Lancet Infect Dis. 2018; 18: 1329-1349Summary Full Text Full Text PDF PubMed Scopus (102) Google Scholar The details of some of their data differ from the latest estimates issued by WHO.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar But both reports are in agreement on one point at least: if the decreases in global tuberculosis incidence and mortality continue at their current, moderate rates, few countries will reach the Sustainable Development Goal (SDG) target of ending the epidemic of tuberculosis by 2030. Over the past two decades, commendable progress has been made in improving tuberculosis control on a global scale.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar, 4Silva DR Dalcolmo M Tiberi S et al.New and repurposed drugs to treat multidrug- and extensively drug-resistant tuberculosis.J Bras Pneumol. 2018; 44 (in English and Portuguese).: 153-160Crossref PubMed Scopus (39) Google Scholar, 5Floyd K Glaziou P Zumla A Raviglione M The global tuberculosis epidemic and progress in care, prevention, and research: an overview in year 3 of the End TB era.Lancet Respir Med. 2018; 6: 299-314Summary Full Text Full Text PDF PubMed Scopus (222) Google Scholar Nevertheless, some scepticism about the chances of meeting this SGD goal in understandable given the rate at which tuberculosis incidence is decreasing compared with the ambitious targets.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar, 6United NationsSustainable development goals: communications materials. New York, NY: United Nations.http://www.un.org/sustainabledevelopment/news/communications-material/Date accessed: October 17, 2018Google Scholar, 7Bloom BR Atun R Cohen T et al.Chapter 11. Tuberculosis.in: Holmes KK Bertozzi S Bloom BR Jha P Major infectious diseases. 3rd edn. The International Bank for Reconstruction and Development/The World Bank, Washington, DC2017Google Scholar To stimulate action towards elimination, goals should be ambitious; however, even humble goals currently seem beyond reach. The data presented on the GBD 2016 study should be a wake-up call to further intensify efforts towards reliable data collection. Although the data are detailed and carefully researched, they are estimated and rely on many assumptions—more primary data are needed from all countries to minimise the need for extrapolation. Our question is, how can this coverage be achieved? The scale of the tuberculosis problem has been recognised and political will to optimise control of the disease exists, as shown by the first United Nations high-level meeting on tuberculosis, held in September, 2018.8The UnionUnited Nations high-level meeting on tuberculosis, 26 September. The International Union Against Tuberculosis and Lung Disease.https://www.theunion.org/un-high-level-meeting-on-tb/Date accessed: October 17, 2018Google Scholar A wealth of measures have been suggested to control tuberculosis. Some lean towards the idea of a magic bullet, such as increased innovation through investment in better diagnostics, novel drugs, and improved treatment regimens for all forms of tuberculosis developed through increased investment and innovation. Others are closer to what might be considered a magic gun, in which existing tools are used more effectively, through better means of delivery and broader implementation of measures that are already available—eg, task-shifting (re-structuring workforces in reponse to the health-care workforce problem), robust tracing and treatment of patients, full recognition of the magnitude of the burden of tuberculosis in countries with low absolute but high relative incidences of the disease, treating hard-to-reach population in otherwise low-incidence countries,9Heuvelings CC de Vries SG Greve PF et al.Effectiveness of interventions for diagnosis and treatment of tuberculosis in hard-to-reach populations in countries of low and medium tuberculosis incidence: a systematic revirew.Lancet Infect Dis. 2017; 17: e144-e158Summary Full Text Full Text PDF PubMed Scopus (52) Google Scholar and refinement of individual treatment strategies. In truth, all of these measures will be needed to address the epidemic of tuberculosis—each will have to be intensively implemented and scaled up in the coming years, if not decades. Even so, some simple and easier to implement measures could be taken to accelerate progress towards controlling tuberculosis. The burden and trends of tuberculosis, tuberculosis in people with HIV/AIDS, multidrug-resistant tuberculosis, and extensively drug-resistant tuberculosis should be assessed with caution. Such caution is especially important in low-income and middle-income countries in sub-Saharan Africa where data accuracy and reliability can be poor, and diagnostic capacity can be inadequate, including for the confirmation of extrapulmonary tuberculosis.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar, 10Lee YJ Diagnosis and treatment of extrapulmonary tuberculosis.Tuberc Respir Dis (Seoul). 2015; 78: 47-55Crossref PubMed Scopus (193) Google Scholar High-quality data is dependent on good surveillance systems, reliable vital registration systems, and quality notification data, but such high-quality data remains difficult to obtain in many parts of the world, including large parts of sub-Saharan Africa. As such, the number of cases of tuberculosis might be over-reported in such areas because of reliance on smear microscopy that can sometimes detect non-tuberculous mycobacteria, or the number of cases might be under-reported because of unreliable sensitivity and specificity of smear microscopy.11Desikan P Tiwari K Panwalkar Nikita et al.Public health relevance of non-tuberculous mycobacteria among AFB positive sputa.Germs. 2017; 7: 10-18Crossref PubMed Google Scholar Investment in novel diagnostics for tuberculosis needs to be intensified to improve global accuracy, and thus, the quality of estimates, and for understanding the actual burden. To understand the actual global tuberculosis situation, the burden sometimes needs to be determined in terms of incidence per capita rather than by use of absolute numbers to enable comparisons with other regions. This method needs to be used cautiously considering that WHO also uses similar criteria to define some of the high tuberculosis burden countries of the world and so direct comparisons could be conflicting.12WHOUse of high burden country lists for TB by WHO in the post-2015 era. World Health Organization, Geneva2015Google Scholar All these approaches to directly address the burden of tuberculosis will need to be supported by governments, non-governmental organisations and agencies, and funders. But there are also broader considerations. In the GBD 2016 tuberculosis study, more than three-quarters of incident cases of tuberculosis and deaths due to tuberculosis in 2016 were in HIV-negative individuals. This fact highlights the importance of considering the social determinants that are sustaining the tuberculosis epidemic other than those related to HIV/AIDS, diabetes, and drug-resistance, as highlighted by GBD 2016.1WHOGlobal tuberculosis report 2018. World Health Organization, Geneva2018Google Scholar, 3GBD Tuberculosis CollaboratorsGlobal, regional, and national burden of tuberculosis from 1990 to 2016: results from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 Study.Lancet Infect Dis. 2018; 18: 1329-1349Summary Full Text Full Text PDF PubMed Scopus (102) Google Scholar, 13Hargreaves JR Boccia D Evans CA Adato M Petticrew M Porter JD The social determinants of tuberculosis: from evidence to action.Am J Public Health. 2011; 101: 654-662Crossref PubMed Scopus (270) Google Scholar The SDGs are interconnected, and health goals can only be achieved if the other SDGs are met too. Global, regional, and national burden of tuberculosis, 1990–2016: results from the Global Burden of Diseases, Injuries, and Risk Factors 2016 StudyIf current trends in tuberculosis incidence continue, few countries are likely to meet the SDG target to end the tuberculosis epidemic by 2030. Progress needs to be accelerated by improving the quality of and access to tuberculosis diagnosis and care, by developing new tools, scaling up interventions to prevent risk factors for tuberculosis, and integrating control programmes for tuberculosis and HIV. Full-Text PDF Open Access