Research in context
Evidence before this study
There is increasing recognition that many individuals surviving tuberculosis face substantial morbidity, are at increased risk of developing tuberculosis again, and have higher all-cause mortality than those who have never had tuberculosis. Tuberculosis can also lead to stigma and can impact the finances of the affected individuals beyond the end of treatment. To identify and support these survivors, the first step is to quantify the number alive today that have had tuberculosis. van Kampen and colleagues did a broad systematic scoping review in which they searched for articles published between 1990 and 2018 on post-tuberculosis morbidity, and found a rapidly accelerating literature in this area. Therefore, to supplement this systematic review, we searched PubMed for articles published in English between Jan 1, 2018, and Aug 8, 2020, using the search terms: (((cure* OR sequel* OR recovered OR resolved OR former OR “history of” OR survivor* OR prior OR healed OR previous* OR post-treatment OR “completed treatment” OR “after treatment”) AND (tubercul* OR TB)) OR (post-tuberculosis OR posttuberculosis OR posttubercular OR post-tubercular OR post-TB OR treated tubercul* OR “treated pulmonary TB” OR “treated pulmonary tuberculosis” OR “treated tb”)) AND (“burden” OR number OR “life year” OR prevalen* OR estimate*) AND 2018:2020[dp]. This search yielded 2804 results. We evaluated these search results and the articles included by van Kampen and colleagues in their systematic review for relevance. In 2011, Denning and colleagues used a simple estimation approach to quantify the global burden of chronic pulmonary aspergillosis in tuberculosis survivors over a 5-year period (and subsequently in four particular countries). We found no articles estimating the numbers of tuberculosis survivors around the world, nor the cumulative life-years lived after tuberculosis disease.
Added value of this study
Our analysis estimates that 363 million people developed tuberculosis between 1980 and 2019, of whom 155 million were alive in 2020. A total of 3480 million life-years were lived in this period by people who had developed tuberculosis. We found that 18% of tuberculosis survivors alive in 2020 were diagnosed and treated in the past 5 years, representing a population that is amenable to identification, screening, and potential therapeutic intervention. Almost half of these tuberculosis survivors were treated in the WHO South-East Asia region and 8% were living with HIV at the time they developed tuberculosis.
Implications of all the available evidence
Tuberculosis programmes have generally focused on finding and diagnosing tuberculosis and supporting individuals to the end of treatment. Our data suggest that there is a large population of tuberculosis survivors who are alive today who would benefit from screening for post-tuberculosis consequences and then, if necessary, medical intervention. Many people might also need financial or social support. More research is required in this field to better understand the pathophysiology, spectrum, and burden of post-tuberculosis morbidity and to develop improved therapies that might prevent or treat those with impairment.