High burden of prevalent tuberculosis among previously treated people in Southern Africa suggests potential for targeted control interventions

Optimizing the cascade of prevention to protect people from tuberculosis: A potential game changer for reducing global tuberculosis incidence

The provision of tuberculosis preventive treatment is one of the critical interventions to reduce tuberculosis incidence and ultimately eliminate the disease, yet we still miss appropriate tools for an impactful intervention and treatment coverage remains low. We used recent data, epidemiological estimates, and research findings to analyze the challenges of each step of the cascade of tuberculosis prevention that currently delay the strategy implementation. We addressed research gaps and implementation bottlenecks that withhold key actions in tuberculosis case finding, testing for tuberculosis infection, provision of preventive treatment with safer, shorter regimens and supporting people to complete their treatment. Empowering communities to generate demand for preventive therapy and other prevention services in a holistic manner and providing adequate financial support to sustain implementation are essential requirements. The adoption of an effective, universal monitoring and evaluation system is a prerequisite to provide general and granular insight, and to steer progress of the tuberculosis infection strategy at global and local level.

A scoping review of interventions to address TB associated respiratory disability

There is a growing body of data describing a high burden of respiratory morbidity amongst pulmonary TB patients and survivors, with up to half thought to experience residual respiratory symptoms, abnormal spirometry, or structural pathology after TB treatment completion. Many patients experiencing marked impacts on their lives and livelihoods. However, there remain no guidelines or evidence-based frameworks for integrated TB-respiratory care during or post TB treatment completion. In this scoping review, completed in collaboration with the WHO Global Tuberculosis Programme, we have identified a lack of primary data on the clinical efficacy, cost effectiveness or feasibility of six potential interventions for the prevention and management of TB-associated respiratory impairment and disability, with a lack of studies in children and adolescents. There is a need for robust interventional trials to improve the long-term respiratory outcomes of people affected by pulmonary TB disease, and to explore how these might be implemented within resource-limited settings.

Baseline and end-of-treatment host serum biomarkers predict relapse in adults with pulmonary tuberculosis

BACKGROUND

There is a need for new tools for monitoring of the response to TB treatment. Such tools may allow for tailored treatment regimens, and stratify patients initiating TB treatment into different risk groups. We evaluated combinations between previously published host biomarkers and new candidates, as tools for monitoring TB treatment response, and prediction of relapse.

METHODS

Serum samples were collected at multiple time points, from patients initiating TB treatment at research sites situated in South Africa (ActionTB study), Brazil and Uganda (TBRU study). Using a multiplex immunoassay platform, we evaluated the concentrations of selected host inflammatory biomarkers in sera obtained from clinically cured patients with and without subsequent relapse within 2 years of TB treatment completion.

RESULTS

A total of 130 TB patients, 30 (23%) of whom had confirmed relapse were included in the study. The median time to relapse was 9.7 months in the ActionTB study (n = 12 patients who relapsed), and 5 months (n = 18 patients who relapsed) in the TBRU study. Serum concentrations of several host biomarkers changed during TB treatment with IL-6, IP-10, IL-22 and complement C3 showing potential individually, in predicting relapse. A six-marker signature comprising of TTP, BMI, sICAM-1, IL-22, IL-1β and complement C3, predicted relapse, prior to the onset of TB treatment with 89% sensitivity and 94% specificity. Furthermore, a 3-marker signature (Apo-CIII, IP-10 and sIL-6R) predicted relapse in samples collected at the end of TB treatment with sensitivity of 71% and specificity of 74%. A previously identified baseline relapse prediction signature (TTP, BMI, TNF-β, sIL-6R, IL-12p40 and IP-10) also showed potential in the current study.

CONCLUSION

Serum host inflammatory biomarkers may be useful in predicting relapse in TB patients prior to the initiation of treatment. Our findings have implications for tailored patient management and require prospective evaluation in larger studies.

Brazilian Thoracic Association recommendations for the management of post-tuberculosis lung disease

Historically, all efforts against tuberculosis were focused on rapid diagnosis and effective treatment to break the chain of transmission of Mycobacterium tuberculosis. However, in the last few years, more and more evidence has been found on the dramatic consequences of the condition defined as post-tuberculosis lung disease (PTLD). Approximately one third of patients surviving pulmonary tuberculosis face considerable ongoing morbidities, including respiratory impairment, psychosocial challenges, and reduced health-related quality of life after treatment completion. Given the important global and local burden of tuberculosis, as well as the estimated burden of PTLD, the development of a consensus document by a Brazilian scientific society-Sociedade Brasileira de Pneumologia e Tisiologia (SBPT)-was considered urgent for the prevention and management of this condition in order to allocate resources to and within tuberculosis services appropriately and serve as a guide for health care professionals. A team of eleven pulmonologists and one methodologist was created by the SBPT to review the current evidence on PTLD and develop recommendations adapted to the Brazilian context. The expert panel selected the topics on the basis of current evidence and international guidelines. During the first phase, three panel members drafted the recommendations, which were divided into three sections: definition and prevalence of PTLD, assessment of PTLD, and management of PTLD. In the second phase, all panel members reviewed, discussed, and revised the recommendations until a consensus was reached. The document was formally approved by the SBPT in a special session organized during the 2023 SBPT Annual Conference.

Evaluating systematic targeted universal testing for tuberculosis in primary care clinics of South Africa: A cluster-randomized trial (The TUTT Trial)

BACKGROUND

The World Health Organization (WHO) recommends systematic symptom screening for tuberculosis (TB). However, TB prevalence surveys suggest that this strategy does not identify millions of TB patients, globally. Undiagnosed or delayed diagnosis of TB contribute to TB transmission and exacerbate morbidity and mortality. We conducted a cluster-randomized trial of large urban and rural primary healthcare clinics in 3 provinces of South Africa to evaluate whether a novel intervention of targeted universal testing for TB (TUTT) in high-risk groups diagnosed more patients with TB per month compared to current standard of care (SoC) symptom-directed TB testing.

METHODS AND FINDINGS

Sixty-two clinics were randomized; with initiation of the intervention clinics over 6 months from March 2019. The study was prematurely stopped in March 2020 due to clinics restricting access to patients, and then a week later due to the Coronavirus Disease 2019 (COVID-19) national lockdown; by then, we had accrued a similar number of TB diagnoses to that of the power estimates and permanently stopped the trial. In intervention clinics, attendees living with HIV, those self-reporting a recent close contact with TB, or a prior episode of TB were all offered a sputum test for TB, irrespective of whether they reported symptoms of TB. We analyzed data abstracted from the national public sector laboratory database using Poisson regression models and compared the mean number of TB patients diagnosed per clinic per month between the study arms. Intervention clinics diagnosed 6,777 patients with TB, 20.7 patients with TB per clinic month (95% CI 16.7, 24.8) versus 6,750, 18.8 patients with TB per clinic month (95% CI 15.3, 22.2) in control clinics during study months. A direct comparison, adjusting for province and clinic TB case volume strata, did not show a significant difference in the number of TB cases between the 2 arms, incidence rate ratio (IRR) 1.14 (95% CI 0.94, 1.38, p = 0.46). However, prespecified difference-in-differences analyses showed that while the rate of TB diagnoses in control clinics decreased over time, intervention clinics had a 17% relative increase in TB patients diagnosed per month compared to the prior year, interaction IRR 1.17 (95% CI 1.14, 1.19, p < 0.001). Trial limitations were the premature stop due to COVID-19 lockdowns and the absence of between-arm comparisons of initiation and outcomes of TB treatment in those diagnosed with TB.

CONCLUSIONS

Our trial suggests that the implementation of TUTT in these 3 groups at extreme risk of TB identified more TB patients than SoC and could assist in reducing undiagnosed TB patients in settings of high TB prevalence.

TRIAL REGISTRATION

South African National Clinical Trials Registry DOH-27-092021-4901.

Yield of Facility-based Targeted Universal Testing for Tuberculosis With Xpert and Mycobacterial Culture in High-Risk Groups Attending Primary Care Facilities in South Africa

BACKGROUND

We report the yield of targeted universal tuberculosis (TB) testing of clinic attendees in high-risk groups.

METHODS

Clinic attendees in primary healthcare facilities in South Africa with one of the following risk factors underwent sputum testing for TB: human immunodeficiency virus (HIV), contact with a TB patient in the past year, and having had TB in the past 2 years. A single sample was collected for Xpert-Ultra (Xpert) and culture. We report the proportion positive for Mycobacterium tuberculosis. Data were analyzed descriptively. The unadjusted clinical and demographic factors' relative risk of TB detected by culture or Xpert were calculated and concordance between Xpert and culture is described.

RESULTS

A total of 30 513 participants had a TB test result. Median age was 39 years, and 11 553 (38%) were men. The majority (n = 21734, 71%) had HIV, 12 492 (41%) reported close contact with a TB patient, and 1573 (5%) reported prior TB. Overall, 8.3% were positive for M. tuberculosis by culture and/or Xpert compared with 6.0% with trace-positive results excluded. In asymptomatic participants, the yield was 6.7% and 10.1% in symptomatic participants (with trace-positives excluded). Only 10% of trace-positive results were culture-positive. We found that 55% of clinic attendees with a sputum result positive for M. tuberculosis did not have a positive TB symptom screen.

CONCLUSIONS

A high proportion of clinic attendees with specific risk factors (HIV, close TB contact, history of TB) test positive for M. tuberculosis when universal testing is implemented.

Post-tuberculosis sequelae in children and adolescents: a systematic review

In 2020, an estimated total of 155 million people had survived tuberculosis. Among this number, a sizable proportion have considerable post-tuberculosis morbidity, as shown for the adult population. This systematic review aims to identify the spectrum and prevalence of post-tuberculosis sequelae in children and adolescents. Four databases were systematically searched from database inception to Feb 7, 2022, for literature on post-treatment outcomes of tuberculosis acquired during childhood. Of the 4613 identified publications, 71 studies were included in this systematic review. Studies on cohorts with comparably rare (most of which were extrapulmonary) tuberculosis presentations, such as spinal tuberculosis and tuberculous meningitis were over-represented; however, no study assessed long-term sequelae in a cohort with an average childhood tuberculosis spectrum. The descriptive analysis includes long-term outcomes of 3529 paediatric patients 1 month to 36 years after confirmed (47%) or clinical (53%) tuberculosis. In a considerable proportion of children, a broad spectrum of post-tuberculosis sequelae were identified, ranging from radiological residua after pulmonary tuberculosis, to disabling deformities after musculoskeletal and cutaneous tuberculosis, to somatic and psychosocial impairment after tuberculous meningitis. A better understanding and comprehensive assessment of post-tuberculosis sequelae in children are needed to improve tuberculosis care beyond antituberculous treatment.

Stakeholder perspectives around post-TB wellbeing and care in Kenya and Malawi

BACKGROUND

There is growing awareness of the burden of post-TB morbidity, and its impact on the lives and livelihoods of TB affected households. However little work has been done to determine how post-TB care might be delivered in a feasible and sustainable way, within existing National TB Programmes (NTPs) and health systems, in low-resource, high TB-burden settings. In this programme of stakeholder engagement around post-TB care, we identified actors with influence and interest in TB care in Kenya and Malawi, including TB-survivors, healthcare providers, policy-makers, researchers and funders, and explored their perspectives on post-TB morbidity and care.

METHODS

Stakeholder mapping was completed to identify actors with interest and influence in TB care services in each country, informed by the study team's local, regional and international networks. Key international TB organisations were included to provide a global perspective. In person or online one-to-one interviews were completed with purposively selected stakeholders. Snowballing was used to expand the network. Data were recorded, transcribed and translated, and a coding frame was derived. Data were coded using NVivo 12 software and were analysed using thematic content analysis. Online workshops were held with stakeholders from Kenya and Malawi to explore areas of uncertainty and validate findings.

RESULTS

The importance of holistic care for TB patients, which addresses both TB comorbidities and sequelae, was widely recognised by stakeholders. Key challenges to implementation include uncertainty around the burden of post-TB morbidity, leadership of post-TB services, funding constraints, staff and equipment limitations, and the need for improved integration between national TB and non-communicable disease (NCD) programmes for care provision and oversight. There is a need for local data on the burden and distribution of morbidity, evidence-informed clinical guidelines, and pilot data on models of care. Opportunities to learn from existing HIV-NCD services were emphasised.

DISCUSSION

This work addresses important questions about the practical implementation of post-TB services in two African countries, exploring if, how, where, and for whom these services should be provided, according to a broad range of stakeholders. We have identified strong interest in the provision of holistic care for TB patients in Kenya and Malawi, and key evidence gaps which must be addressed to inform decision making by policy makers, TB programmes, and funders around investment in post-TB services. There is a need for pilot studies of models of integrated TB care, and for cross-learning between countries and from HIV-NCD services.

TB morbidity estimates overlook the contribution of post-TB disability: evidence from urban Malawi

INTRODUCTION

Despite growing evidence of the long-term impact of tuberculosis (TB) on quality of life, Global Burden of Disease (GBD) estimates of TB-related disability-adjusted life years (DALYs) do not include post-TB morbidity, and evaluations of TB interventions typically assume treated patients return to pre-TB health. Using primary data, we estimate years of life lost due to disability (YLDs), years of life lost due to premature mortality (YLL) and DALYs associated with post-TB cardiorespiratory morbidity in a low-income country.

METHODS

Adults aged ≥15 years who had successfully completed treatment for drug-sensitive pulmonary TB in Blantyre, Malawi (February 2016-April 2017) were followed-up for 3 years with 6-monthly and 12-monthly study visits. In this secondary analysis, St George's Respiratory Questionnaire data were used to match patients to GBD cardiorespiratory health states and corresponding disability weights (DWs) at each visit. YLDs were calculated for the study period and estimated for remaining lifespan using Malawian life table life expectancies. YLL were estimated using study mortality data and aspirational life expectancies, and post-TB DALYs derived. Data were disaggregated by HIV status and gender.

RESULTS

At treatment completion, 222/403 (55.1%) participants met criteria for a cardiorespiratory DW, decreasing to 15.6% after 3 years, at which point two-thirds of the disability burden was experienced by women. Over 90% of projected lifetime-YLD were concentrated within the most severely affected 20% of survivors. Mean DWs in the 3 years post-treatment were 0.041 (HIV-) and 0.025 (HIV+), and beyond 3 years estimated as 0.025 (HIV-) and 0.010 (HIV+), compared with GBD DWs of 0.408 (HIV+) and 0.333 (HIV-) during active disease. Our results imply that the majority of TB-related morbidity occurs post-treatment.

CONCLUSION

TB-related DALYs are greatly underestimated by overlooking post-TB disability. The total disability burden of TB is likely undervalued by both GBD estimates and economic evaluations of interventions, particularly those aimed at early diagnosis and prevention.

Revamping of Chronic Respiratory Diseases in Low- and Middle-Income Countries

Low- and middle-income countries (LMICs) endure an asymmetrically high burden of worldwide disease and death caused by chronic respiratory diseases (CRDs), i.e., asthma, emphysema, bronchiectasis, and post-tuberculosis lung disease (PTLD). CRDs are firmly related with indigence, infectious diseases, and other non-communicable diseases (NCDs) and add to complex multi-disease with great impact on the lives and livelihood of those affected. The pertinence of CRDs to health and demographic wellbeing is relied upon to increment in the long time ahead, as expectations of life rise and the contending dangers of right on time youth mortality and irresistible infections level. The WHO has distinguished the counteraction and control of NCDs as an earnest improvement issue and crucial for the sustainable development goals (SDSs) by 2030. In this review, we center on CRDs in LMICs. We examine the early life roots of CRDs, challenges in their avoidance, identification and administration in LMICs, and the pathways to resolve for accomplish valid widespread wellbeing inclusion.

Spatially targeted digital chest radiography to reduce tuberculosis in high-burden settings: a study of adaptive decision making

Background:

Spatially-targeted approaches to screen for tuberculosis (TB) could accelerate TB control in high-burden populations. We aimed to estimate gains in case-finding yield under an adaptive decision-making approach for spatially-targeted, mobile digital chest radiography (dCXR)-based screening in communities with varying levels of TB prevalence.

Methods:

We used a Monte-Carlo simulation model to simulate a spatially-targeted screening intervention in 24 communities with TB prevalence estimates derived from a large community-randomized trial. We implemented a Thompson sampling algorithm to allocate screening units based on Bayesian probabilities of local TB prevalence that are continuously updated during weekly screening rounds. Four mobile units for dCXR-based screening and subsequent Xpert Ultra-based testing were allocated among the communities during a 52-week period. We estimated the yield of bacteriologically-confirmed TB per 1000 screenings comparing scenarios of spatially-targeted and untargeted resource allocation.

Results:

We estimated that under the untargeted scenario, an expected 666 (95% uncertainty interval 522–825) TB cases would be detected over one year, equivalent to 8.9 (7.5–10.3) per 1000 individuals screened. Allocating the screening units to the communities with the highest (prior-year) cases notification rates resulted in an expected 760 (617–926) TB cases detected, 10.1 (8.6–11.8) per 1000 screened. Adaptive, spatially-targeted screening resulted in an expected 1241 (995–1502) TB cases detected, 16.5 (14.5–18.7) per 1000 screened. Numbers of dCXR-based screenings needed to detect one additional TB case declined during the first 12–14 weeks as a result of Bayesian learning.

Conclusion:

We introduce a spatially-targeted screening strategy that could reduce the number of screenings necessary to detect additional TB in high-burden settings and thus improve the efficiency of screening interventions. Empirical trials are needed to determine whether this approach could be successfully implemented.

Clinical standards for the assessment, management and rehabilitation of post-TB lung disease

BACKGROUND: Increasing evidence suggests that post-TB lung disease (PTLD) causes significant morbidity and mortality. The aim of these clinical standards is to provide guidance on the assessment and management of PTLD and the implementation of pulmonary rehabilitation (PR).METHODS: A panel of global experts in the field of TB care and PR was identified; 62 participated in a Delphi process. A 5-point Likert scale was used to score the initial ideas for standards and after several rounds of revision the document was approved (with 100% agreement).RESULTS: Five clinical standards were defined: Standard 1, to assess patients at the end of TB treatment for PTLD (with adaptation for children and specific settings/situations); Standard 2, to identify patients with PTLD for PR; Standard 3, tailoring the PR programme to patient needs and the local setting; Standard 4, to evaluate the effectiveness of PR; and Standard 5, to conduct education and counselling. Standard 6 addresses public health aspects of PTLD and outcomes due to PR.CONCLUSION: This is the first consensus-based set of Clinical Standards for PTLD. Our aim is to improve patient care and quality of life by guiding clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage PTLD.

Impact of post-tuberculosis lung disease on health-related quality of life in patients from two tertiary hospitals in Lagos, Nigeria

Background

Post-tuberculosis (TB) lung disease is a recognised cause of chronic respiratory disease, and its impact on health-related quality of life (HRQoL) has not been extensively described.

Objectives

To describe the clinical profile, spirometry impairment and impact of post-TB lung disease on HRQoL among patients attending two tertiary hospitals in Lagos, Nigeria.

Methods

We conducted a cross-sectional study and obtained data through interviews, chart reviews and physical examination. We measured dyspnoea severity using the Medical Research Council (MRC) scale, HRQoL with the St George’s respiratory questionnaire (SGRQ) and performed spirometry. Univariate regression was used to explore the associations between selected variables and HRQoL.

Results

A total of 59 participants were recruited and their median (interquartile range (IQR)) age was 45 (36 - 60) years. The most frequent symptom was cough (93.2%; n=55) and sputum production (91.5%; n=54). Less than two-thirds of the participants (62.4%; n=38) had received treatment for TB on more than one occasion, 50.8% (n=30) had moderate to very severe dyspnoea on the MRC scale and 88.7% (n=47/53) had abnormal spirometry with the mixed pattern predominating in 56.6% (n=30) of the participants. The mean (standard deviation (SD)) SGRQ component score for symptoms was 43.89 (18.66), followed by activity (42.50 (22.68)), impact (29.41 (17.82)) and total components (35.78 (17.25)). Dyspnoea, cough, sputum production and weight loss were associated with worsened HRQoL.

Conclusion

Post-TB lung disease was characterised by a high symptom burden, severe spirometry impairment and poor HRQoL. There is a need for increased recognition and development of guidelines for diagnosis and treatment of post-TB lung disease and for further studies to explore preventive strategies.

Digital chest radiography enhances screening efficiency for pulmonary tuberculosis in primary health clinics, South Africa

BACKGROUND

Optimized tuberculosis (TB) screening in high burden settings is essential for case finding. We evaluated digital chest x-ray with computer-aided detection (CAD) software (d-CXR) for identifying undiagnosed TB in three primary health clinics in South Africa.

METHODS

The cross-sectional study consented adults who were sequentially screened for TB using the World Health Organization (WHO) four symptom questionnaire and d-CXR. Participants reporting ≥1 TB symptom and/or CAD score ≥60 (suggestive of TB) provided two spot sputum for Xpert MTB/RIF Ultra (Xpert Ultra) and liquid culture testing respectively. TB yield (proportion of screened tested positive) and number needed to test [NNT] (no of tests to identify one TB patient) were calculated. Risk factors for microbiologically confirmed or presumed (on radiological grounds) were determined.

RESULTS

Among 3041 participants, 45% (1356/3,041) screened positive on either d-CXR or symptoms. TB yield was 2.3% (71/3041) using Xpert Ultra and 2.7% (82/3041) using Xpert Ultra plus culture. Modelled TB yield (identified by Xpert Ultra) by screening approach was: 1.9% (59/3041) for d-CXR alone, 2.0% (62/3041) for symptoms alone and 2.3% (71/3041) for both. The NNT was 9.7 for d-CXR, 17.8 for symptoms and 19.1 for d-CXR and/or symptom. Males, those with previous TB, untreated HIV or unknown HIV status, and acute illness were at higher risk of developing TB.

CONCLUSION

d-CXR screening identified a similar yield of undiagnosed TB compared to symptom-based screening, however required fewer diagnostic tests. Due to its objective nature, d-CXR screening may improve case detection in clinics.

Quantifying the global number of tuberculosis survivors: a modelling study

BACKGROUND

People who survive tuberculosis face clinical and societal consequences after recovery, including increased risks of recurrent tuberculosis, premature death, reduced lung function, and ongoing stigma. To describe the size of this issue, we aimed to estimate the number of individuals who developed first-episode tuberculosis between 1980 and 2019, the number who survived to 2020, and the number who have been treated within the past 5 years or 2 years.

METHODS

In this modelling study, we estimated the number of people who survived treated tuberculosis using country-level WHO data on tuberculosis case notifications, excluding those who died during treatment. We estimated the number of individuals surviving untreated tuberculosis using the difference between WHO country-level incidence estimates and notifications, applying published age-stratified and HIV-stratified case fatality ratios. To estimate survival with time, post-tuberculosis life tables were developed for each country-year by use of UN World Population Prospects 2019 mortality rates and published post-tuberculosis mortality hazard ratios.

FINDINGS

Between 1980 and 2019, we estimate that 363 million people (95% uncertainty interval [UI] 287 million-438 million) developed tuberculosis, of whom 172 million (169 million-174 million) were treated. Individuals who developed tuberculosis between 1980 and 2019 had lived 3480 million life-years (95% UI 3040 million-3920 million) after tuberculosis by 2020, with survivors younger than 15 years at the time of tuberculosis development contributing 12% (95% UI 7-17) of these life-years. We estimate that 155 million tuberculosis survivors (95% UI 138 million-171 million) were alive in 2020, the largest proportion (47% [37-57]) of whom were in the WHO South-East Asia region. Of the tuberculosis survivors who were alive in 2020, we estimate that 18% (95% UI 16-20) were treated in the past 5 years and 8% (7-9) were treated in the past 2 years.

INTERPRETATION

The number of tuberculosis survivors alive in 2020 is more than ten times the estimated annual tuberculosis incidence. Interventions to alleviate respiratory morbidity, screen for and prevent recurrent tuberculosis, and reduce stigma should be immediately prioritised for recently treated tuberculosis survivors.

FUNDING

UK Medical Research Council, the UK Department for International Development, the National Institute for Health Research, and the European and Developing Countries Clinical Trials Partnership.

'TB is a disease which hides in the body': Qualitative data on conceptualisations of tuberculosis recurrence among patients in Zambia and South Africa

The WHO estimates 58 million people experienced one or more TB disease episodes between 2000 and 2018. These 'former TB patients' are at greater risk of future TB infection and death than TB naïve people. Additionally, former TB patients experience social, psychological, and physiological difficulties after microbiological cure. Drawing on semi-structured interviews collected with 28 people from communities in Zambia (n = 8) and South Africa (n = 2) between October 2018 and March 2019, we describe their perceptions of having two or more TB episodes. Utilising a discursive analytic approach, we interrogated how participants conceptualise their risk of disease recurrence. Despite being surprised by subsequent TB episodes, participants utilised their bodily experiences of TB signs and symptoms alongside their experiential knowledge of health systems processes to procure timely diagnosis and care. Yet, many participants were unable to resume social and economic participation. Experiences of multiple TB episodes and correlating social, economic, and physiological vulnerabilities, challenged participants biomedical understanding of TBs curability. Through notions of dirt and 'staining', participants conceptualise TB as a sinister, malicious presence they are bound to encounter time and again. Health providers should discuss the risk of TB recurrence with patients and promote prevention, early detection, and diagnosis of TB disease.

Improving lung health in low-income and middle-income countries: from challenges to solutions

Low-income and middle-income countries (LMICs) bear a disproportionately high burden of the global morbidity and mortality caused by chronic respiratory diseases (CRDs), including asthma, chronic obstructive pulmonary disease, bronchiectasis, and post-tuberculosis lung disease. CRDs are strongly associated with poverty, infectious diseases, and other non-communicable diseases (NCDs), and contribute to complex multi-morbidity, with major consequences for the lives and livelihoods of those affected. The relevance of CRDs to health and socioeconomic wellbeing is expected to increase in the decades ahead, as life expectancies rise and the competing risks of early childhood mortality and infectious diseases plateau. As such, the World Health Organization has identified the prevention and control of NCDs as an urgent development issue and essential to the achievement of the Sustainable Development Goals by 2030. In this Review, we focus on CRDs in LMICs. We discuss the early life origins of CRDs; challenges in their prevention, diagnosis, and management in LMICs; and pathways to solutions to achieve true universal health coverage.

Post-Tuberculosis Lung Disease: Clinical Review of an Under-Recognised Global Challenge

An estimated 58 million people have survived tuberculosis since 2000, yet many of them will suffer from post-tuberculosis lung disease (PTLD). PTLD results from a complex interplay between organism, host, and environmental factors and affects long-term respiratory health. PTLD is an overlapping spectrum of disorders that affects large and small airways (bronchiectasis and obstructive lung disease), lung parenchyma, pulmonary vasculature, and pleura and may be complicated by co-infection and haemoptysis. People affected by PTLD have shortened life expectancy and increased risk of recurrent tuberculosis, but predictors of long-term outcomes are not known. No data are available on PTLD in children and on impact throughout the life course. Risk-factors for PTLD include multiple episodes of tuberculosis, drug-resistant tuberculosis, delays in diagnosis, and possibly smoking. Due to a lack of controlled trials in this population, no evidence-based recommendations for the investigation and management of PTLD are currently available. Empirical expert opinion advocates pulmonary rehabilitation, smoking cessation, and vaccinations (pneumococcal and influenza). Exacerbations in PTLD remain both poorly understood and under-recognised. Among people with PTLD, the probability of tuberculosis recurrence must be balanced against other causes of symptom worsening. Unnecessary courses of repeated empiric anti-tuberculosis chemotherapy should be avoided. PTLD is an important contributor to the global burden of chronic lung disease. Advocacy is needed to increase recognition for PTLD and its associated economic, social, and psychological consequences and to better understand how PTLD sequelae could be mitigated. Research is urgently needed to inform policy to guide clinical decision-making and preventative strategies for PTLD.

Risk of developing active tuberculosis following tuberculosis screening and preventive therapy for Tibetan refugee children and adolescents in India: An impact assessment

BACKGROUND

Tuberculosis (TB) rates among Tibetan refugee children and adolescents attending boarding schools in India are extremely high. We undertook a comprehensive case finding and TB preventive treatment (TPT) program in 7 schools in the Zero TB Kids project. We aimed to measure the TB infection and disease burden and investigate the risk of TB disease in children and adults who did and did not receive TPT in the schools.

METHODS AND FINDINGS

A mobile team annually screened children and staff for TB at the 7 boarding schools in Himachal Pradesh, India, using symptom criteria, radiography, molecular diagnostics, and tuberculin skin tests. TB infection (TBI) was treated with short-course regimens of isoniazid and rifampin or rifampin. TB disease was treated according to Tibetan and Indian guidelines. Between April 2017 and December 2019, 6,582 schoolchildren (median age 14 [IQR 11-16] years) and 807 staff (median age 40 [IQR 33-48] years) were enrolled. Fifty-one percent of the students and 58% of the staff were females. Over 13,161 person-years of follow-up in schoolchildren (median follow-up 2.3 years) and 1,800 person-years of follow-up in staff (median follow-up 2.5 years), 69 TB episodes occurred in schoolchildren and 4 TB episodes occurred in staff, yielding annual incidence rates of 524/100,000 (95% CI 414-663/100,000) person-years and 256/100,000 (95% CI 96-683/100,000) person-years, respectively. Of 1,412 schoolchildren diagnosed with TBI, 1,192 received TPT. Schoolchildren who received TPT had 79% lower risk of TB disease (adjusted hazard ratio [aHR] 0.21; 95% CI 0.07-0.69; p = 0.010) compared to non-recipients, the primary study outcome. Protection was greater in recent contacts (aHR 0.07; 95% CI 0.01-0.42; p = 0.004), the secondary study outcome. The prevalence of recent contacts was 28% (1,843/6,582). Two different TPT regimens were used (3HR and 4R), and both were apparently effective. No staff receiving TPT developed TB. Overall, between 2017 and 2019, TB disease incidence decreased by 87%, from 837/100,000 (95% CI 604-1,129/100,000) person-years to 110/100,000 (95% CI 36-255/100,000) person-years (p < 0.001), and TBI prevalence decreased by 42% from 19% (95% CI 18%-20%) to 11% (95% CI 10%-12%) (p < 0.001). A limitation of our study is that TB incidence could be influenced by secular trends during the study period.

CONCLUSIONS

In this study, following implementation of a school-wide TB screening and preventive treatment program, we observed a significant reduction in the burden of TB disease and TBI in children and adolescents. The benefit of TPT was particularly marked for recent TB contacts. This initiative may serve as a model for TB detection and prevention in children and adolescents in other communities affected by TB.

The long term effect of pulmonary tuberculosis on income and employment in a low income, urban setting

Background

Mitigating the socioeconomic impact of tuberculosis (TB) is key to the WHO End TB Strategy. However, little known about socioeconomic well-being beyond TB-treatment completion. In this mixed-methods study, we describe socioeconomic outcomes after TB-disease in urban Blantyre, Malawi, and explore pathways and barriers to financial recovery.

Methods

Adults ≥15 years successfully completing treatment for a first episode of pulmonary TB under the National TB Control Programme were prospectively followed up for 12 months. Socioeconomic, income, occupation, health seeking and cost data were collected. Determinants and impacts of ongoing financial hardship were explored through illness narrative interviews with purposively selected participants.

Results

405 participants were recruited from February 2016 to April 2017. Median age was 35 years (IQR: 28–41), 67.9% (275/405) were male, and 60.6% (244/405) were HIV-positive. Employment and incomes were lowest at TB-treatment completion, with limited recovery in the following year: fewer people were in paid work (63.0% (232/368) vs 72.4% (293/405), p=0.006), median incomes were lower (US$44.13 (IQR: US$0–US$106.15) vs US$72.20 (IQR: US$26.71–US$173.29), p<0.001), and more patients were living in poverty (earning <US$1.90/day: 57.7% (211/366) vs 41.6% (166/399), p<0.001) 1 year after TB-treatment completion compared with before TB-disease onset. Half of the participants (50.5%, 184/368) reported ongoing dissaving (use of savings, selling assets, borrowing money) and 9.5% (35/368) reported school interruptions in the year after TB-treatment completion. Twenty-one participants completed in-depth interviews. Reported barriers to economic recovery included financial insecurity, challenges rebuilding business relationships, residual physical morbidity and stigma.

Conclusions

TB-affected households remain economically vulnerable even after TB-treatment completion, with limited recovery in income and employment, persistent financial strain requiring dissaving, and ongoing school interruptions. Measures of the economic impact of TB disease should include the post-TB period. Interventions to protect the long-term health and livelihoods of TB survivors must be explored.

Risk factors for recurrent tuberculosis after successful treatment in a high burden setting: a cohort study

BACKGROUND

People successfully completing treatment for tuberculosis remain at elevated risk for recurrent disease, either from relapse or reinfection. Identifying risk factors for recurrent tuberculosis may help target post-tuberculosis screening and care.

METHODS

We enrolled 500 patients with smear-positive pulmonary tuberculosis in South Africa and collected baseline data on demographics, clinical presentation and sputum mycobacterial cultures for 24-loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing. We used routinely-collected administrative data to identify recurrent episodes of tuberculosis occurring over a median of six years after successful treatment completion.

RESULTS

Of 500 patients initially enrolled, 333 (79%) successfully completed treatment for tuberculosis. During the follow-up period 35 patients with successful treatment (11%) experienced a bacteriologically confirmed tuberculosis recurrence. In our Cox proportional hazards model, a 3+ AFB sputum smear grade was significantly associated with recurrent tuberculosis with a hazard ratio of 3.33 (95% CI 1.44-7.7). The presence of polyclonal M. tuberculosis infection at baseline had a hazard ratio for recurrence of 1.96 (95% CI 0.86-4.48).

CONCLUSION

Our results indicate that AFB smear grade is independently associated with tuberculosis recurrence after successful treatment for an initial episode while the association between polyclonal M. tuberculosis infection and increased risk of recurrence appears possible.

Cost-effectiveness of post-treatment follow-up examinations and secondary prevention of tuberculosis in a high-incidence setting: a model-based analysis

BACKGROUND

In settings of high tuberculosis incidence, previously treated individuals remain at high risk of recurrent tuberculosis and contribute substantially to overall disease burden. Whether tuberculosis case finding and preventive interventions among previously treated people are cost-effective has not been established. We aimed to estimate costs and health benefits of annual post-treatment follow-up examinations and secondary preventive therapy for tuberculosis in a tuberculosis-endemic setting.

METHODS

We developed a transmission-dynamic mathematical model and calibrated it to data from two high-incidence communities of approximately 40 000 people in suburban Cape Town, South Africa. We used the model to estimate overall cost and disability-adjusted life-years (DALYs) associated with annual follow-up examinations and secondary isoniazid preventive therapy (IPT), alone and in combination, among individuals completing tuberculosis treatment. We investigated scenarios under which these interventions were restricted to the first year after treatment completion, or extended indefinitely. For each intervention scenario, we projected health system costs and DALYs averted with respect to the current status quo of tuberculosis control. All estimates represent mean values derived from 1000 epidemic trajectories simulated over a 10-year period (2019-28), with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values.

FINDINGS

We estimated that a single follow-up examination at the end of the first year after treatment completion combined with 12 months of secondary IPT would avert 2472 DALYs (95% UI -888 to 7801) over a 10-year period and is expected to be cost-saving compared with current control efforts. Sustained annual follow-up and continuous secondary IPT beyond the first year after treatment would avert an additional 1179 DALYs (-1769 to 4377) over 10 years at an expected additional cost of US$18·2 per DALY averted. Strategies of follow-up without secondary IPT were dominated (ie, expected to result in lower health impact at higher costs) by strategies that included secondary IPT.

INTERPRETATION

In this high-incidence setting, post-treatment follow-up and secondary preventive therapy can accelerate declines in tuberculosis incidence and potentially save resources for tuberculosis control. Empirical trials to assess the feasibility of these interventions in settings most severely affected by tuberculosis are needed.

FUNDING

National Institutes of Health, Günther Labes Foundation, Oskar Helene Heim Foundation.

The Importance of Heterogeneity to the Epidemiology of Tuberculosis

Although less well-recognized than for other infectious diseases, heterogeneity is a defining feature of tuberculosis (TB) epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment, and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming that average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants, or comorbidities could improve efficiency, but raise ethical and equity considerations.

Closing gaps in the tuberculosis care cascade: an action-oriented research agenda

The care cascade-which evaluates outcomes across stages of patient engagement in a health system-is an important framework for assessing quality of tuberculosis (TB) care. In recent years, there has been progress in measuring care cascades in high TB burden countries; however, there are still shortcomings in our knowledge of how to reduce poor patient outcomes. In this paper, we outline a research agenda for understanding why patients fall through the cracks in the care cascade. The pathway for evidence generation will require new systematic reviews, observational cohort studies, intervention development and testing, and continuous quality improvement initiatives embedded within national TB programs. Certain gaps, such as pretreatment loss to follow-up and post-treatment disease recurrence, should be a priority given a relative paucity of high-quality research to understand and address poor outcomes. Research on interventions to reduce death and loss to follow-up during treatment should move beyond a focus on monitoring (or observation) strategies, to address patient needs including psychosocial and nutritional support. While key research questions vary for each gap, some patient populations may experience disparities across multiple stages of care and should be a priority for research, including men, individuals with a prior treatment history, and individuals with drug-resistant TB. Closing gaps in the care cascade will require investments in a bold and innovative action-oriented research agenda.

Subtherapeutic Rifampicin Concentration Is Associated With Unfavorable Tuberculosis Treatment Outcomes

BACKGROUND

The relationships between first-line drug concentrations and clinically important outcomes among patients with tuberculosis (TB) remain poorly understood.

METHODS

We enrolled a prospective cohort of patients with new pulmonary TB receiving thrice-weekly treatment in India. The maximum plasma concentration of each drug was determined at months 1 and 5 using blood samples drawn 2 hours postdose. Subtherapeutic cutoffs were: rifampicin <8 µg/mL, isoniazid <3 µg/mL, and pyrazinamide <20 µg/mL. Factors associated with lower log-transformed drug concentrations, unfavorable outcomes (composite of treatment failure, all-cause mortality, and recurrence), and individual outcomes were examined using Poisson regression models.

RESULTS

Among 404 participants, rifampicin, isoniazid, and pyrazinamide concentrations were subtherapeutic in 85%, 29%, and 13%, respectively, at month 1 (with similar results for rifampicin and isoniazid at month 5). Rifampicin concentrations were lower with human immunodeficiency virus coinfection (median, 1.6 vs 4.6 µg/mL; P = .015). Unfavorable outcome was observed in 19%; a 1-μg/mL decrease in rifampicin concentration was independently associated with unfavorable outcome (adjusted incidence rate ratio [aIRR], 1.21 [95% confidence interval {CI}, 1.01-1.47]) and treatment failure (aIRR, 1.16 [95% CI, 1.05-1.28]). A 1-μg/mL decrease in pyrazinamide concentration was associated with recurrence (aIRR, 1.05 [95% CI, 1.01-1.11]).

CONCLUSIONS

Rifampicin concentrations were subtherapeutic in most Indian patients taking a thrice-weekly TB regimen, and low rifampicin and pyrazinamide concentrations were associated with poor outcomes. Higher or more frequent dosing is needed to improve TB treatment outcomes in India.

Patient outcomes associated with post-tuberculosis lung damage in Malawi: a prospective cohort study

BACKGROUND

Post-tuberculosis lung damage (PTLD) is a recognised consequence of pulmonary TB (pTB). However, little is known about its prevalence, patterns and associated outcomes, especially in sub-Saharan Africa and HIV-positive adults.

METHODS

Adult (≥15 years) survivors of a first episode of pTB in Blantyre, Malawi, completed the St George's Respiratory Questionnaire, 6-minute walk test, spirometry and high-resolution CT (HRCT) chest imaging at TB treatment completion. Symptom, spirometry, health seeking, TB-retreatment and mortality data were collected prospectively to 1 year. Risk factors for persistent symptoms, pulmonary function decline and respiratory-related health-seeking were identified through multivariable regression modelling.

RESULTS

Between February 2016 and April 2017, 405 participants were recruited. Median age was 35 years (IQR: 28 to 41), 77.3% (313/405) had had microbiologically proven pTB, and 60.3% (244/403) were HIV-positive. At pTB treatment completion, 60.7% (246/405) reported respiratory symptoms, 34.2% (125/365) had abnormal spirometry, 44.2% (170/385) had bronchiectasis ≥1 lobe and 9.4% (36/385) had ≥1 destroyed lobe on HRCT imaging. At 1 year, 30.7% (113/368) reported respiratory symptoms, 19.3% (59/305) and 14.1% (43/305) of patients had experienced declines in FEV₁ or FVC of ≥100 mL, 16.3% (62/380) had reported ≥1 acute respiratory event and 12.2% (45/368) had symptoms affecting their ability to work.

CONCLUSIONS

PTLD is a common and under-recognised consequence of pTB that is disabling for patients and associated with adverse outcomes beyond pTB treatment completion. Increased efforts to prevent PTLD and guidelines for management of established disease are urgently needed. Low-cost clinical interventions to improve patient outcomes must be evaluated.

Treatment as prevention and other interventions to reduce transmission of multidrug-resistant tuberculosis

Drug-resistant tuberculosis (DR-TB) represents a major programmatic challenge at the national and global levels. Only ∼30% of patients with multidrug-resistant TB (MDR-TB) were diagnosed, and ∼25% were initiated on treatment for MDR-TB in 2016. Increasing evidence now points towards primary transmission of DR-TB, rather than inadequate treatment, as the main driver of the DR-TB epidemic. The cornerstone of DR-TB transmission prevention should be earlier diagnosis and prompt initiation of effective treatment for all patients with DR-TB. Despite the extensive scale-up of Xpert^® MTB/RIF testing, major implementation barriers continue to limit its impact. Although there is longstanding evidence in support of the rapid impact of treatment on patient infectiousness, delays in the initiation of effective DR-TB treatment persist, resulting in ongoing transmission. However, it is also imperative to address the burden of latent drug-resistant tuberculous infection because it is estimated that many DR-TB patients will become infectious before seeking care and encounter various diagnostic delays before treatment. Addressing latent DR-TB primarily consists of identifying, treating and following the contacts of patients with MDR-TB, typically through household contact evaluation. Adjunctive measures, such as improved ventilation and use of germicidal ultraviolet technology can further reduce TB transmission in high-risk congregate settings. Although many gaps remain in our biological understanding of TB transmission, implementation barriers to early diagnosis and rapid initiation of effective DR-TB treatment can and must be overcome if we are to impact DR-TB incidence in the short and long term.

Morbidity and mortality up to 5 years post tuberculosis treatment in South Africa: A pilot study

BACKGROUND

A high risk of tuberculosis (TB), chronic lung disease, and mortality have been reported among people with a history of previous TB treatment, but data from high-incidence settings remain limited. The aim of this study was to characterize general morbidity and mortality among adults who had successfully completed TB treatment in the past 5 years in a high-incidence setting in South Africa.

METHODS

Adults (≥18 years) who had completed treatment for pulmonary TB between 2013 and 2017 were randomly selected from TB treatment registers. Household visits were conducted to locate and interview former TB (FTB) patients, and bacteriological testing for TB was offered. Additional data sources were used to ascertain the vitality status of FTB patients who could not be located.

RESULTS

Addresses were located for 200 of the 223 FTB patients sampled and 89 FTB patients were contacted of whom 51 agreed to be interviewed. Approximately half reported persistent respiratory symptoms, such as shortness of breath and wheezing, and repeated lung infections. One (3.6%) of 28 patients who provided a sputum sample had culture-positive TB and another two were currently on re-treatment for TB. Fifteen deaths post treatment were ascertained, resulting in a standardized mortality ratio of 3.8 (95% confidence interval 2.3-6.3) after successful TB treatment relative to the general population.

CONCLUSIONS

In this high-incidence setting, locating and interviewing FTB patients was challenging. The study findings are consistent with a high rate of respiratory disease, including recurrent TB, and substantially elevated mortality among FTB patients.

FAST implementation in Bangladesh: high frequency of unsuspected tuberculosis justifies challenges of scale-up

SETTING

National Institute of Diseases of the Chest and Hospital, Dhaka; Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders, Dhaka; and Chittagong Chest Disease Hospital, Chittagong, Bangladesh.

OBJECTIVE

To present operational data and discuss the challenges of implementing FAST (Find cases Actively, Separate safely and Treat effectively) as a tuberculosis (TB) transmission control strategy.

DESIGN

FAST was implemented sequentially at three hospitals.

RESULTS

Using Xpert® MTB/RIF, 733/6028 (12.2%, 95%CI 11.4-13.0) patients were diagnosed with unsuspected TB. Patients with a history of TB who were admitted with other lung diseases had more than twice the odds of being diagnosed with unsuspected TB as those with no history of TB (OR 2.6, 95%CI 2.2-3.0, P < 0.001). Unsuspected multidrug-resistant TB (MDR-TB) was diagnosed in 89/1415 patients (6.3%, 95%CI 5.1-7.7). Patients with unsuspected TB had nearly five times the odds of being diagnosed with MDR-TB than those admitted with a known TB diagnosis (OR 4.9, 95%CI 3.1-7.6, P < 0.001). Implementation challenges include staff shortages, diagnostic failure, supply-chain issues and reliance on external funding.

CONCLUSION

FAST implementation revealed a high frequency of unsuspected TB in hospitalized patients in Bangladesh. Patients with a previous history of TB have an increased risk of being diagnosed with unsuspected TB. Ensuring financial resources, stakeholder engagement and laboratory capacity are important for sustainability and scalability.

Tuberculosis control interventions targeted to previously treated people in a high-incidence setting: a modelling study

BACKGROUND

In high-incidence settings, recurrent disease among previously treated individuals contributes substantially to the burden of incident and prevalent tuberculosis. The extent to which interventions targeted to this high-risk group can improve tuberculosis control has not been established. We aimed to project the population-level effect of control interventions targeted to individuals with a history of previous tuberculosis treatment in a high-incidence setting.

METHODS

We developed a transmission-dynamic model of tuberculosis and HIV in a high-incidence setting with a population of roughly 40 000 people in suburban Cape Town, South Africa. The model was calibrated to data describing local demography, TB and HIV prevalence, TB case notifications and treatment outcomes using a Bayesian calibration approach. We projected the effect of annual targeted active case finding in all individuals who had previously completed tuberculosis treatment and targeted active case finding combined with lifelong secondary isoniazid preventive therapy. We estimated the effect of these targeted interventions on local tuberculosis incidence, prevalence, and mortality over a 10 year period (2016-25).

FINDINGS

We projected that, under current control efforts in this setting, the tuberculosis epidemic will remain in slow decline for at least the next decade. Additional interventions targeted to previously treated people could greatly accelerate these declines. We projected that annual targeted active case finding combined with secondary isoniazid preventive therapy in those who previously completed tuberculosis treatment would avert 40% (95% uncertainty interval [UI] 21-56) of incident tuberculosis cases and 41% (16-55) of tuberculosis deaths occurring between 2016 and 2025.

INTERPRETATION

In this high-incidence setting, the use of targeted active case finding in combination with secondary isoniazid preventive therapy in previously treated individuals could accelerate decreases in tuberculosis morbidity and mortality. Studies to measure cost and resource implications are needed to establish the feasibility of this type of targeted approach for improving tuberculosis control in settings with high tuberculosis and HIV prevalence.

FUNDING

National Institutes of Health, German Research Foundation.