Post-tuberculosis lung impairment: systematic review and meta-analysis of spirometry data from 14 621 people

The prevalence and pattern of post tuberculosis lung disease including pulmonary hypertension from an Australian TB service; a single-centre, retrospective cohort study

INTRODUCTION

Post Tuberculosis Lung Disease (PTLD) is increasingly recognised as a significant cause of morbidity internationally, but has not been described in an Australian setting. We aimed to determine the prevalence of PTLD among adult TB survivors from an Australian TB service and describe the pattens of lung function abnormalities and pulmonary disease, including pulmonary hypertension.

METHODS

We conducted a single-centre retrospective cohort study in Sydney, Australia, including all adults who successfully completed TB treatment between January 2013 and December 2022. Baseline characteristics, post treatment pulmonary function, and thoracic computed tomography (CT) data were analysed to determine the prevalence and patterns of PTLD, defined as any lung function and/or radiological abnormality attributable to TB.

RESULTS

Among 119 confirmed TB patients (mean age 46 ± 21 years, 61% males) PTLD was identified in 81/119 (68%). Pulmonary function testing was available for 51/119 (43%), of whom 38/51(75%) exhibited abnormalities. Obstructive deficits were found in 25/51 (49%), restrictive deficits in 11/51 (22%), and impaired gas transfer capacity in 26/51 (51%). Chest CT scans were completed in 76/119 (64%), with 70/76 (92%) demonstrating significant abnormalities, including pulmonary fibrosis 43/76 (57%), bronchiectasis 22/76 (29%), and emphysema 11/76 (15%). Pulmonary hypertension was suspected in 52/76 (68%) patients based on radiological findings.

CONCLUSION

Despite successful treatment, PTLD was frequently observed among our cohort of Australian TB survivors. Further research into optimal screening practices to diagnose chronic pulmonary diseases and pulmonary hypertension could provide opportunities for earlier intervention and management.

High risk of drug-resistant tuberculosis in IGRA-negative contacts: should preventive treatment be considered?

PURPOSE

Deciding whether to provide preventive treatment to contacts of individuals with multidrug-resistant (MDR) tuberculosis is complex.

METHODS

We present the diagnostic pathways, clinical course and outcome of tuberculosis treatment in eight siblings from a single family. Tuberculosis disease was diagnosed by Mycobacterium tuberculosis culture and molecular detection of M. tuberculosis-specific DNA from bronchopulmonary specimens using GeneXpert® MTB/RIF. M. tuberculosis infection was diagnosed by an interferon-gamma release assay (IGRA; QuantiFERON®-TB Gold Plus). Whole exome sequencing for genetic predisposition to mycobacterial infection was performed in one patient.

RESULTS

Six of eight siblings aged 16-20 years from a migrant family of Somali origin were diagnosed with pulmonary MDR tuberculosis over a 12-month period. The remaining male siblings, aged 11 and 14 years, were asymptomatic during contact investigation. Chest radiographs, computed tomography (CT) scans, sputum cultures and nucleic acid amplification tests were negative, and the IGRA did not detect M. tuberculosis infection. A repeat CT scan eight months later was unremarkable, and repeated sputum cultures remained negative. In the absence of sufficient evidence of M. tuberculosis infection, no preventive treatment was offered. At month seven of consistent clinical observation, both children were diagnosed with pulmonary tuberculosis; the older with advanced disease and subsequent post-tuberculosis lung disease. Whole exome sequencing revealed no Mendelian variant associated with susceptibility to mycobacterial infection.

CONCLUSION

When significant risk of tuberculosis transmission exists, close contacts of MDR tuberculosis patients should be offered preventive treatment with levofloxacin despite a negative IGRA test result.

Identification of Post-Tuberculosis Lung Function Impairment Early during the Course of Treatment

Tuberculosis (TB) is a leading cause of morbidity and mortality and an important contributory factor to chronic lung disease. TB-associated permanent lung damage manifests with varying levels of respiratory disability long after TB has been successfully treated, which is a condition known as post-TB lung disease (PTLD). This study assessed whether lung function impairment associated with PTLD occurs early during TB treatment. Using a cross-sectional design, we enrolled newly diagnosed adult TB patients aged ≥18 years who had received anti-TB medication for ≥2 months from a large treatment center in northern Nigeria. We used spirometry and the Global Lung Initiative 2012 reference equations for African Americans to assess and characterize lung function for enrolled participants (N = 94). The median age (range) of participants was 34 (18-72) years. Approximately 5.3% (n = 5) of participants exhibited features of abnormal lung function, 4.2% (n = 4) showed features of obstructive lung abnormality, and 1.1% (n = 1) showed restrictive lung abnormality. Compared with historical patients recruited ≥6 months after TB treatment in the same center, our participants had significantly lower forced expiratory volume in one second and forced vital capacity values. Our findings suggest an opportunity for early intervention for primary and secondary prevention of PTLD to reduce the impact of severe respiratory impairment.

Post-TB sequelae in adolescent pulmonary TB survivors

OBJECTIVE

To compare the persistent clinical symptoms, chest X-ray (CXR), spirometry and echocardiography results in adolescent survivors of drug-susceptible (DS) and drug-resistant (DR) pulmonary TB (PTB).

METHODS

This retrospective cohort study was conducted in 52 adolescent PTB survivors. We compared persistent clinical symptoms, CXR, spirometry and echocardiography in DS-TB and DR-TB survivors. χ2 test was used to compare groups (P < 0.05 significant), logistic regression analysis was used to identify risk factors, and Many-Factor Rasch Measurement Version Facets 3.86.0 was used to assess the multi-rater agreement of CXR.

RESULTS

Significant differences were found in persistent clinical symptoms (higher in DS-TB survivors), CXR, and spirometry abnormalities (higher in DR-TB survivors). The echocardiography revealed a low pulmonary hypertension probability in both groups. Adolescent PTB survivors with comorbidity have 1.5 times the risk of developing pulmonary sequelae compared to non-sequelae.

CONCLUSION

Pulmonary sequelae in adolescent PTB survivors were documented in both DS and DR-TB. Monitoring after treatment completion was necessary for PTB survivors, especially in adolescents.

Advances in the awareness of tuberculosis-associated chronic obstructive pulmonary disease

Tuberculosis (TB) significantly increases the risk of developing chronic obstructive pulmonary disease (COPD), positioning TB-associated COPD (TB-COPD) as a distinct category within the spectrum of respiratory diseases prevalent, especially in low- and middle-income countries. This condition results from the body's immune response to TB, leading to prolonged inflammation and consequent persistent lung damage. Diagnostic approaches, particularly post-bronchodilator spirometry, are vital for identifying airflow obstruction and confirming TB-COPD. Furthermore, exploring potential biomarkers is crucial for a deeper insight into the pathogenesis of TB-COPD and the improvement of treatment strategies. Currently, this condition is primarily managed using inhaled bronchodilators, with cautious use of inhaled corticosteroids advised owing to the increased risk of developing TB. This review delves into the epidemiology, clinical manifestations, pulmonary function, and imaging characteristics of TB-COPD, scrutinizing current and prospective biomarkers and therapeutic strategies. Furthermore, it underscores the necessity for focused research to bridge the knowledge and treatment gaps in this complex condition.

Surgical treatment outcomes and risk factors for post-TB lung disease

OBJECTIVE

This study aims to investigate the effectiveness and safety of surgical treatment for post-TB lung disease (PTLD) and to analyse its risk factors.

METHODS

Data were collected from 268 patients who underwent pulmonary resection for TB in Xi'an Chest Hospital, Xi'an, Shaanxi, China, between January 2014 and December 2023. The efficacy and safety of the three groups were compared, and the TB group was used as the control group to analyse the risk factors of PTLD.

RESULTS

The results indicated the three groups in intraoperative blood loss, post-operative drainage volume, post-operative complications, and post-operative hospital stay also varied significantly among the three groups (all P < 0.01). Additionally, factors such as pre-operative anti-TB therapy duration (OR = 1.02, P = 0.007), age (OR = 1.03, P = 0.030), and comorbid diabetes mellitus (OR = 3.00, P = 0.046) were identified as significant contributors to PTLD. While pre-operative haemoptysis demonstrates a statistically significant correlation with both precursor PTLDs, this association likely reflects the clinical expression of the underlying disease process.

CONCLUSION

The study confirms that surgery for PTLD is safe and efficacious. Patients with advanced age, an extended duration of pre-operative anti-TB therapy, comorbid diabetes mellitus and pre-operative haemoptysis should maintain vigilance regarding the potential development of PTLD.

Pulmonary tuberculosis in non-HIV adults: an evergreen old-fashioned disease in high-income countries. A narrative review

INTRODUCTION

Tuberculosis (TB), an infective air-borne disease with worldwide non-homogeneous distribution, remains a top cause of morbidity and mortality. TB control is linked to early diagnosis and proper treatment of contagious TB cases and infected subjects at high risk of developing TB.

AREAS COVERED

A narrative review of pulmonary TB in non-HIV adults with reference to high-income countries. Modern medicine offers several advancements in diagnostics and therapeutics of TB, but they often remain to be extensively implemented in real life. In high-income countries TB is now relatively uncommon, but it remains a health and socio-economic burden that should not be underestimated.

EXPERT OPINION

Pulmonologists should maintain expertise toward TB for several reasons. First, the lung is the most common and the infectious moiety of TB. Second, TB remains a global issue due to common travels of western people and migrations from areas with high incidence of TB. Third, as TB has heterogenous clinics, its prompt diagnosis may be difficult. Fourth, TB is a curable disease, but its management is complex and predisposes to poor adherence with failures/relapses and selection of drug-resistant strains.

Tuberculosis-Associated Respiratory Disability in Children, Adolescents, and Adults: Protocol for a Systematic Review and Individual Participant Data Meta-Analysis

Background

Approximately 2% of the global population has survived tuberculosis (TB). Increasing evidence indicates that a significant proportion of pulmonary TB survivors develop TB-associated respiratory disability, commonly referred to as post-TB lung disease (PLTD) and marked by impaired respiratory function, persistent symptoms, and activity limitations. However, the prevalence, risk factors, and progression of TB-associated respiratory disability throughout the life course are not well understood. To address these gaps, we will undertake a systematic review and individual participant-level data meta-analysis (IPD-MA) focusing on TB-associated respiratory disability in children, adolescents, and adults successfully treated for pulmonary TB.

Methods and analysis

We will systematically search MEDLINE, Embase, CENTRAL, Global Index Medicus, and medRxiv for original studies investigating TB-associated respiratory disability in people of all ages who have completed treatment for microbiologically confirmed or clinically diagnosed pulmonary TB. Authors of eligible studies will be invited to contribute de-identified data and form a collaborative group. Primary outcomes will be (1) abnormal lung function based on spirometry parameters and (2) chronic respiratory symptoms. We will estimate the overall and subgroup-specific prevalence of each outcome through IPD meta-analysis. Next, we will develop clinical prediction tools assessing the risk of future TB-associated respiratory disability at (i) the start of TB treatment and (ii) end of TB treatment for those without existing signs of disability. Finally, we will use stepwise hierarchical modelling to identify epidemiological determinants of respiratory disability.

Ethics and dissemination

This study has been approved by the ethics review boards at the Rhode Island Hospital (2138217-2) and the Research Institute of the McGill University Health Centre (2024-10345). Individual study authors will be required to obtain institutional approval prior to sharing data. Results will be disseminated through open-access, peer-reviewed publications and conference presentations.

Prospero registration number

CRD42024529906.

The epidemiology, transmission, diagnosis, and management of drug-resistant tuberculosis-lessons from the South African experience

Drug-resistant tuberculosis (DR-TB) threatens to derail tuberculosis control efforts, particularly in Africa where the disease remains out of control. The dogma that DR-TB epidemics are fueled by unchecked rates of acquired resistance in inadequately treated or non-adherent individuals is no longer valid in most high DR-TB burden settings, where community transmission is now widespread. A large burden of DR-TB in Africa remains undiagnosed due to inadequate access to diagnostic tools that simultaneously detect tuberculosis and screen for resistance. Furthermore, acquisition of drug resistance to new and repurposed drugs, for which diagnostic solutions are not yet available, presents a major challenge for the implementation of novel, all-oral, shortened (6-9 months) treatment. Structural challenges including poverty, stigma, and social distress disrupt engagement in care, promote poor treatment outcomes, and reduce the quality of life for people with DR-TB. We reflect on the lessons learnt from the South African experience in implementing state-of-the-art advances in diagnostic solutions, deploying recent innovations in pharmacotherapeutic approaches for rapid cure, understanding local transmission dynamics and implementing interventions to curtail DR-TB transmission, and in mitigating the catastrophic socioeconomic costs of DR-TB. We also highlight globally relevant and locally responsive research priorities for achieving DR-TB control in South Africa.

Destroyed lung syndrome in patients with drug-susceptible pulmonary tuberculosis

Destroyed lung syndrome is a recognized devastating complication of pulmonary tuberculosis (TB) that affects the quality of life of patients. Clinicians in TB-endemic countries should be aware of this complication aiming at prevention. TB control programs should intensify efforts at early detection and treatment and also provide interventions for post-TB complications.

Global, regional, and national burden of HIV-negative tuberculosis, 1990-2021: findings from the Global Burden of Disease Study 2021

BACKGROUND

Tuberculosis (TB) is a major infectious disease with significant public health implications. Its widespread transmission, prolonged treatment duration, notable side effects, and high mortality rate pose severe challenges. This study examines the epidemiological characteristics of TB globally and across major regions, providing a scientific basis for enhancing TB prevention and control measures worldwide.

METHODS

The ecological study used data from the Global Burden of Disease (GBD) Study 2021. It assessed new incidence cases, deaths, disability-adjusted life years (DALYs), and trends in age-standardized incidence rates (ASIRs), mortality rates (ASMRs), and DALY rates for drug-susceptible tuberculosis (DS-TB), multidrug-resistant tuberculosis (MDR-TB), and extensively drug-resistant tuberculosis (XDR-TB) from 1990 to 2021. A Bayesian age-period-cohort model was applied to project ASIR and ASMR.

RESULTS

In 2021, the global ASIR for all HIV-negative TB was 103.00 per 100,000 population [95% uncertainty interval (UI): 92.21, 114.91 per 100,000 population], declining by 0.40% (95% UI: - 0.43, - 0.38%) compared to 1990. The global ASMR was 13.96 per 100,000 population (95% UI: 12.61, 15.72 per 100,000 population), with a decline of 0.44% (95% UI: - 0.61, - 0.23%) since 1990. The global age-standardized DALY rate for HIV-negative TB was 580.26 per 100,000 population (95% UI: 522.37, 649.82 per 100,000 population), showing a decrease of 0.65% (95% UI: - 0.69, - 0.57 per 100,000 population) from 1990. The global ASIR of MDR-TB has not decreased since 2015, instead, it has shown a slow upward trend in recent years. The ASIR of XDR-TB has exhibited significant increase in the past 30 years. The projections indicate MDR-TB and XDR-TB are expected to see significant increases in both ASIR and ASMR from 2022 to 2035, highlighting the growing challenge of drug-resistant TB.

CONCLUSIONS

This study found that the ASIR of MDR-TB and XDR-TB has shown an upward trend in recent years. To reduce the TB burden, it is essential to enhance health infrastructure and increase funding in low-SDI regions. Developing highly efficient, accurate, and convenient diagnostic reagents, along with more effective therapeutic drugs, and improving public health education and community engagement, are crucial for curbing TB transmission.

Implications of progressive lung damage and post-TB sequelae for the health benefits of prompt TB diagnosis in high HIV prevalence settings: a mathematical modeling analysis

Background

Untreated pulmonary tuberculosis (TB) causes ongoing lung damage, which may persist after treatment. Conventional approaches for assessing TB health effects may not fully capture these mechanisms. We evaluated how TB-associated lung damage and post-TB sequalae affect the lifetime health consequences of TB in high HIV prevalence settings.

Methods

We developed a microsimulation model representing dynamic changes in lung function for individuals evaluated for TB in routine clinical settings. We parameterized the model with data for Uganda, Kenya, and South Africa, and estimated lifetime health outcomes under prompt, delayed, and no TB treatment scenarios. We compared results to earlier modelling approaches that omit progressive lung damage and post-TB sequelae.

Findings

We estimated 4.6 (95% uncertainty interval 3.4-5.8), 7.2 (5.1-9.6), and 18.0 (15.1-20.0) year reductions in life expectancy due to TB under prompt, delayed, and no treatment scenarios, respectively. Disability-adjusted life years (DALYs) from TB were estimated as 8.3 (6.2-10.6), 12.6 (9.0-17.0), and 27.8 (24.1-30.6) under prompt, delayed, and no treatment scenarios, respectively. Post-TB DALYs represented 9-53% of total DALYs. Modelling approaches that omit progressive lung damage and post-TB sequelae underestimated lifetime health losses of TB by 48-57%, and underestimated the benefits of prompt treatment by 45-64%.

Interpretation

Delayed initiation of TB treatment causes greater lung damage and higher mortality risks during and after the disease episode. In settings with co-prevalent TB and HIV, accounting for these factors substantially increased estimates of the lifetime disease burden and life expectancy loss caused by TB.

Funding

NIH.

ISCCM Position Statement on the Approach to and Management of Critically Ill Patients with Tuberculosis

Tuberculosis (TB) is an important cause of morbidity and mortality globally. About 3-4% of hospitalized TB patients require admission to the intensive care unit (ICU); the mortality in these patients is around 50-60%. There is limited literature on the evaluation and management of patients with TB who required ICU admission. The Indian Society of Critical Care Medicine (ISCCM) constituted a working group to develop a position paper that provides recommendations on the various aspects of TB in the ICU setting based on available evidence. Seven domains were identified including the categorization of TB in the critically ill, diagnostic workup, drug therapy, TB in the immunocompromised host, organ support, infection control, and post-TB sequelae. Forty-one questions pertaining to these domains were identified and evidence-based position statements were generated, where available, keeping in focus the critical care aspects. Where evidence was not available, the recommendations were based on consensus. This position paper guides the approach to and management of critically ill patients with TB.

How to cite this article

Chacko B, Chaudhry D, Peter JV, Khilnani G, Saxena P, Sehgal IS, et al. isccm Position Statement on the Approach to and Management of Critically Ill Patients with Tuberculosis. Indian J Crit Care Med 2024;28(S2):S67-S91.

Tuberculosis Is Associated with Chronic Hypoxemia among Kenyan Adults (CHAKA): A Case-Control Study

Rationale: Data on risk factors for chronic hypoxemia in low- and middle-income countries are lacking. Objectives: We aimed to quantify the association between potential risk factors and chronic hypoxemia among adults hospitalized in Kenya. Methods: A hospital-based, case-control study was conducted at Moi Teaching and Referral Hospital in Eldoret, Kenya. Adult inpatients were screened on admission and enrolled in a 1:2 case-to-control ratio. Cases were patients with chronic hypoxemia, defined as resting oxygen saturation as measured by pulse oximetry (SpO2) ⩽ 88% on admission and either 1-month postdischarge SpO2 ⩽ 88% or, if they died before follow-up, documented SpO2 ⩽ 88% in the 6 months before enrollment. Control subjects were randomly selected, stratified by sex, among nonhypoxemic inpatients. Data were collected using questionnaires and structured chart review. Regression was used to assess the associations between chronic hypoxemia and age, sex, smoking status, biomass fuel use, elevation, and self-reported history of tuberculosis and human immunodeficiency virus diagnosis. Odds ratios (ORs) and 95% confidence intervals (CIs) are reported. Results: We enrolled 108 chronically hypoxemic cases and 240 nonhypoxemic control subjects into our Chronic Hypoxemia among Kenyan Adults (CHAKA) cohort. In multivariable analysis, compared with control subjects, chronically hypoxemic cases had significantly higher odds of older age (OR, 1.2 per 5-year increase [95% CI, 1.1-1.3]), female sex (OR, 3.6 [95% CI, 1.8-7.2]), current or former tobacco use (OR, 4.7 [95% CI, 2.3-9.6]), and prior tuberculosis (OR, 11.8 [95% CI, 4.7-29.6]) but no increase in the odds of human immunodeficiency virus diagnosis and biomass fuel use. Conclusions: These findings highlight the potential impact of prior tuberculosis on chronic lung disease in Kenya and the need for further studies on posttuberculosis lung disease.

Unveiling Silent Consequences: Impact of Pulmonary Tuberculosis on Lung Health and Functional Wellbeing after Treatment

Background: Pulmonary tuberculosis (TB) remains a major public health issue in India, with high incidence and mortality. The current literature on post-TB sequelae functional defects focuses heavily on spirometry, with conflicting obstruction vs. restriction data, lacks advanced statistical analysis, and has insufficient data on diffusion limitation and functional impairment. Objective: This study aimed to thoroughly evaluate post-tubercular sequelae after treatment, assessing chest radiology, spirometry, diffusing capacity, and exercise capacity. Methods: A total of 85 patients were studied at a university teaching hospital in Mysuru. The data collected included characteristics, comorbidities, smoking history, and respiratory symptoms. The investigations included spirometry, DLCO, chest X-rays with scoring, and 6MWT. Results: Of the patients, 70% had abnormal X-rays post-treatment, correlating with reduced lung function. Additionally, 70% had impaired spirometry with obstructive/restrictive patterns, and 62.2% had reduced DLCO, with females at higher risk. Smoking increased the risk of sequelae. Conclusions: Most patients had residual radiological/lung function abnormalities post-treatment. Advanced analyses provide insights into obstructive vs. restrictive defects. Ongoing research should explore pathogenetic mechanisms and therapeutic modalities to minimize long-term post-TB disability.

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.

Proposed Etiotypes for Chronic Obstructive Pulmonary Disease: Controversial Issues

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) revised the definition of chronic obstructive pulmonary disease (COPD) to broadly include a variety of etiologies. A new taxonomy, composed of etiotypes, aims to highlight the heterogeneity in causes and pathogenesis of COPD, allowing more personalized management strategies and emphasizing the need for targeted research to understand and manage COPD better. However, controversy arises with including some diseases under the umbrella term of COPD, as their clinical presentations and treatments differ from classical COPD, which is smoking-related. COPD due to infection (COPD-I) and COPD due to environmental exposure (COPD-P) are classifications within the new taxonomy. Some disease entities in these categories show distinct clinical features and may not benefit from conventional COPD treatments, raising questions about their classification as COPD subtypes. There is also controversy regarding whether bronchiectasis with airflow limitations should be classified as an etiotype of COPD. This article discusses controversial issues associated with the proposed etiotypes for COPD in terms of COPD-I, COPD-P, and bronchiectasis. While the updated COPD definition by GOLD 2023 is a major step towards recognizing the disease's complexity, it also raises questions about the classification of related respiratory conditions. This highlights the need for further research to improve our understanding and approach to COPD management.

Understanding the Spectrum and Management of Post-Tuberculosis Lung Disease: A Comprehensive Review

Post-tuberculosis lung disease (PTLD) poses a significant clinical challenge in regions with a high burden of tuberculosis (TB). This review provides a comprehensive overview of PTLD, encompassing its pathogenesis, clinical manifestations, diagnostic modalities, management strategies, long-term outcomes, and public health implications. PTLD arises from residual lung damage following TB treatment and is characterized by a spectrum of pathological changes, including fibrosis, bronchiectasis, and cavitation. Clinical presentation varies widely, from chronic cough and hemoptysis to recurrent respiratory infections, which are oftentimes a diagnostic dilemma. Radiological imaging, pulmonary function tests, and careful consideration of patient history play pivotal roles in diagnosis. Management strategies involve pharmacological interventions to alleviate symptoms and prevent disease progression, which are influenced by the extent of lung damage, comorbidities, and access to healthcare. Rehabilitation programs and surgical options are available for select cases. Prognosis is influenced by the extent of lung damage, comorbidities, and access to healthcare. Prevention efforts through a TB control program and early detection are crucial in reducing the burden of PTLD. This review stresses the importance of understanding and addressing PTLD to mitigate its impact on individuals and public health systems worldwide.

Lung outcomes and related risk factors in patients after SARS-CoV-2 infection: a hospitalised single-centre cohort from Johannesburg, South Africa

Background

Sequelae post-SARS-CoV-2 infection, including lung and functional impairment, pose a significant challenge post-recovery. We explored the burden and risk factors for post-COVID-19 sequelae in an African population with prevalent comorbidities including tuberculosis (TB) and HIV.

Methods

We conducted an observational cohort study on hospitalised adults with confirmed SARS-CoV-2 infection from 20 March to 06 October 2021 at Chris Hani Baragwanath Academic Hospital, South Africa. We collected data on comorbidities, and COVID-19 severity using the World Health Organization (WHO) clinical progression scale. Prospectively, we followed up all participants within 40-days post-discharge to assess body mass index (BMI), COVID-19 symptoms and quality of life using St George's Respiratory Questionnaire (SGRQ), 6-min walking-test (6MWT), and spirometry. A subsequent in-depth visit assessed plethysmography, diffusing capacity for the lung for carbon monoxide (DLCO), and high-resolution chest-CT.

Findings

We followed up 111 participants, where 65.8% were female, median age 50.5 years, and predominantly black-African (92.8%). Relevant comorbidities included TB disease (18.9%) and HIV infection (36%). SGRQ total scores were elevated in 78.9%, median 6MWT distance was reduced at 300 m (IQR 210-400), and nearly half (49.5%) exhibited spirometry findings below the lower limit of normal (LLN). In-depth pulmonary assessment for 61 participants revealed abnormalities in total lung capacity (31.6% <80% predicted), DLCO (53.4% <80% predicted), and chest-CT (86.7% abnormal). Significant risk factors for individual abnormal outcomes, adjusted for age and sex, were TB disease, HIV with CD4 <200 cells/mm3, BMI <18.5 kg/m2 and >35 kg/m2, and initial COVID-19 severity.

Interpretation

This study demonstrates substantial lung and functional morbidity within the first weeks post-COVID-19, particularly in individuals with pre-existing comorbidities including TB, HIV, and low or high BMI. Chest-CT and DLCO show best early potential at reflecting COVID-19-related pathologies.

Funding

The Bavarian State Ministry of Science and Arts.

Multidrug-resistant tuberculosis

Tuberculosis (TB) remains the foremost cause of death by an infectious disease globally. Multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB; resistance to rifampicin and isoniazid, or rifampicin alone) is a burgeoning public health challenge in several parts of the world, and especially Eastern Europe, Russia, Asia and sub-Saharan Africa. Pre-extensively drug-resistant TB (pre-XDR-TB) refers to MDR/RR-TB that is also resistant to a fluoroquinolone, and extensively drug-resistant TB (XDR-TB) isolates are additionally resistant to other key drugs such as bedaquiline and/or linezolid. Collectively, these subgroups are referred to as drug-resistant TB (DR-TB). All forms of DR-TB can be as transmissible as rifampicin-susceptible TB; however, it is more difficult to diagnose, is associated with higher mortality and morbidity, and higher rates of post-TB lung damage. The various forms of DR-TB often consume >50% of national TB budgets despite comprising <5-10% of the total TB case-load. The past decade has seen a dramatic change in the DR-TB treatment landscape with the introduction of new diagnostics and therapeutic agents. However, there is limited guidance on understanding and managing various aspects of this complex entity, including the pathogenesis, transmission, diagnosis, management and prevention of MDR-TB and XDR-TB, especially at the primary care physician level.

Integrated plasma proteomics identifies tuberculosis-specific diagnostic biomarkers

BACKGROUNDNovel biomarkers to identify infectious patients transmitting Mycobacterium tuberculosis are urgently needed to control the global tuberculosis (TB) pandemic. We hypothesized that proteins released into the plasma in active pulmonary TB are clinically useful biomarkers to distinguish TB cases from healthy individuals and patients with other respiratory infections.METHODSWe applied a highly sensitive non-depletion tandem mass spectrometry discovery approach to investigate plasma protein expression in pulmonary TB cases compared to healthy controls in South African and Peruvian cohorts. Bioinformatic analysis using linear modeling and network correlation analyses identified 118 differentially expressed proteins, significant through 3 complementary analytical pipelines. Candidate biomarkers were subsequently analyzed in 2 validation cohorts of differing ethnicity using antibody-based proximity extension assays.RESULTSTB-specific host biomarkers were confirmed. A 6-protein diagnostic panel, comprising FETUB, FCGR3B, LRG1, SELL, CD14, and ADA2, differentiated patients with pulmonary TB from healthy controls and patients with other respiratory infections with high sensitivity and specificity in both cohorts.CONCLUSIONThis biomarker panel exceeds the World Health Organization Target Product Profile specificity criteria for a triage test for TB. The new biomarkers have potential for further development as near-patient TB screening assays, thereby helping to close the case-detection gap that fuels the global pandemic.FUNDINGMedical Research Council (MRC) (MR/R001065/1, MR/S024220/1, MR/P023754/1, and MR/W025728/1); the MRC and the UK Foreign Commonwealth and Development Office; the UK National Institute for Health Research (NIHR); the Wellcome Trust (094000, 203135, and CC2112); Starter Grant for Clinical Lecturers (Academy of Medical Sciences UK); the British Infection Association; the Program for Advanced Research Capacities for AIDS in Peru at Universidad Peruana Cayetano Heredia (D43TW00976301) from the Fogarty International Center at the US NIH; the UK Technology Strategy Board/Innovate UK (101556); the Francis Crick Institute, which receives funding from UKRI-MRC (CC2112); Cancer Research UK (CC2112); and the NIHR Biomedical Research Centre of Imperial College NHS.

Burden, clinical features, and outcomes of post-tuberculosis chronic obstructive lung diseases

PURPOSE OF REVIEW

Post-tuberculosis lung disease (PTLD) is an increasingly recognized and debilitating consequence of pulmonary tuberculosis (PTB). In this review, we provide a comprehensive overview of PTLD with airflow obstruction (PTLD-AFO), focusing on its burden, pathophysiology, clinical manifestations, diagnostic methods, and management strategies.

RECENT FINDINGS

The relationship between PTLD and airflow obstruction is complex and multifactorial. Approximately 60% of the patients with PTLD have some spirometric abnormality. Obstruction is documented in 18-22% of PTLD patients. The host susceptibility and host response to mycobacterium drive the pathogenic mechanism of PTLD. A balance between inflammatory, anti-inflammatory, and fibrotic pathways decides whether an individual with PTB would have PTLD after microbiological cure. An obstructive abnormality in PTLD-AFO is primarily due to destruction of bronchial walls, aberrant healing, and reduction of mucosal glands. The most common finding on computed tomography (CT) of thorax in patients with PTLD-AFO is bronchiectasis and cavitation. Therefore, the 'Cole's vicious vortex' described in bronchiectasis applies to PTLD. A multidisciplinary approach is required for diagnosis and treatment. The disability-adjusted life-years (DALYs) attributed to PTLD represent about 50% of the total estimated burden of DALYs due to tuberculosis (TB). Patients with PTLD require comprehensive care that includes psychosocial support, pulmonary rehabilitation, and vaccination against respiratory pathogens. In the absence of trials evaluating different treatments for PTLD-AFO, therapy is primarily symptomatic.

SUMMARY

PTLD with airflow obstruction has considerable burden and causes a significant morbidity and mortality. However, many aspects of PTLD-AFO still need to be answered. Studies are required to evaluate different phenotypes, especially concerning Aspergillus -related complications. The treatment should be personalized based on the predominant phenotype of airflow obstruction. Extensive studies to understand the exact burden, pathogenesis, and treatment of PTBLD-AFO are needed.

Pulmonary function outcomes after tuberculosis treatment in children: a systematic review and meta-analysis

BACKGROUND

Despite tuberculosis (TB) being a curable disease, current guidelines fail to account for the long-term outcomes of post-tuberculosis lung disease-a cause of global morbidity despite successful completion of effective treatment. Our systematic review aimed to synthesise the available evidence on the lung function outcomes of childhood pulmonary tuberculosis (PTB).

METHODS

PubMed, ISI Web of Science, Cochrane Library and ProQuest databases were searched for English-only studies without time restriction (latest search date 22 March 2023). Inclusion criteria were (1) patients who had TB with pulmonary involvement at age ≤18 years; (2) pulmonary function tests (PFTs) performed on patients after treatment completion; and (3) observational studies, including cohort and cross-sectional studies. We adhered to the recommendations of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

From 8040 records, 5 studies were included (involving n=567 children), with spirometry measures from 4 studies included in the meta-analyses. The effect sizes of childhood TB on forced expiratory volume in the first second and forced vital capacity z-scores were estimated to be -1.53 (95% CI -2.65, -0.41; p=0.007) and -1.93 (95% CI -3.35, -0.50; p=0.008), respectively.

DISCUSSION

The small number of included studies reflects this under-researched area, relative to the global burden of TB. Nevertheless, as childhood PTB impacts future lung function, PFTs (such as spirometry) should be considered a routine test when evaluating the long-term lung health of children beyond their completion of TB treatment. PROSPERO registration number CRD42021250172.

Chronic Pulmonary Aspergillosis as a Considerable Complication in Post-Tuberculosis Lung Disease

Post-tuberculosis lung disease (PTLD) has only recently been put in the spotlight as a medical entity. Recent data suggest that up to 50% of tuberculosis (TB) patients are left with PTLD-related impairment after completion of TB treatment. The presence of residual cavities in the lung is the largest risk factor for the development of chronic pulmonary aspergillosis (CPA) globally. Diagnosis of CPA is based on four criteria including a typical radiological pattern, evidence of Aspergillus species, exclusion of alternative diagnosis, and a chronic course of disease. In this manuscript, we provide a narrative review on CPA as a serious complication for patients with PTLD.

Screening for post-TB lung disease at TB treatment completion: Are symptoms sufficient?

Pulmonary TB survivors face a high burden of post-TB lung disease (PTLD) after TB treatment completion. In this secondary data analysis we investigate the performance of parameters measured at TB treatment completion in predicting morbidity over the subsequent year, to inform programmatic approaches to PTLD screening in low-resource settings. Cohort data from urban Blantyre, Malawi were used to construct regression models for five morbidity outcomes (chronic respiratory symptoms or functional limitation, ongoing health seeking, spirometry decline, self-reported financial impact of TB disease, and death) in the year after PTB treatment, using three modelling approaches: logistic regression; penalised regression with pre-selected predictors; elastic net penalised regression using the full parent dataset. Predictors included demographic, clinical, symptom, spirometry and chest x-ray variables. The predictive performance of models were examined using the area under the receiver-operator curve (ROC AUC) values. Key predictors were identified, and their positive and negative predictive values (NPV) determined. The presence of respiratory symptoms at TB treatment completion was the strongest predictor of morbidity outcomes. TB survivors reporting breathlessness had higher odds of spirometry decline (aOR 20.5, 95%CI:3-199.1), health seeking (aOR 10.2, 2.4-50), and symptoms or functional limitation at 1-year (aOR 16.7, 3.3-133.4). Those reporting activity limitation were more likely to report symptoms or functional limitation at 1-year (aOR 4.2, 1.8-10.3), or severe financial impact of TB disease (aOR2.3, 1.0-5.0). Models were not significantly improved by including spirometry or imaging parameters. ROC AUCs were between 0.65-0.77 for the morbidity outcomes. Activity limitation at treatment completion had a NPV value of 78-98% for adverse outcomes. Our data suggest that whilst challenging to predict the development of post-TB morbidity, the use of symptom screening tools at TB treatment completion to prioritise post-TB care should be explored. We identified little benefit from the additional use of spirometry or CXR imaging.

Impaired lung function in adolescents with pulmonary tuberculosis during treatment and following treatment completion

Background

Little is known about post-tuberculosis lung disease in adolescents. We prospectively assessed lung function in adolescents with microbiologically confirmed pulmonary tuberculosis during treatment and after treatment completion.

Methods

In a prospective study, we enrolled adolescents diagnosed with microbiologically confirmed tuberculosis and healthy tuberculosis-exposed household controls, between October 2020 and July 2021 in Cape Town, South Africa. Spirometry, plethysmography, diffusion capacity lung function tests and 6-min walking test (6MWT) were completed according to international guidelines 2 months into treatment and following treatment completion. Abnormal lung function was defined as abnormal spirometry (z-score < -1.64 for forced expiratory volume in 1 s (FEV1) and/or forced vital capacity (FVC) and/or FEV1/FVC), plethysmography (total lung capacity (TLC) < 80% of predicted, residual volume over TLC of >45%) and/or diffusion capacity (DLCO z-score < -1.64).

Findings

One-hundred adolescents were enrolled; 50 (50%) with tuberculosis and 50 (50%) healthy tuberculosis-exposed controls. Of the 50 adolescents with tuberculosis, ten had multidrug-resistant tuberculosis. Mean age of the group was 14.9 years (SD 2.7), 6 (6.0%) were living with HIV and 9 (9.0%) were previously treated for tuberculosis. Lung function improved over time; during treatment abnormal lung function was found in 76% of adolescents with tuberculosis, compared to 65% after treatment completion. Spirometry indices were lower in adolescents with tuberculosis compared to controls, both at 2 months and after treatment completion. Plethysmography in adolescents with tuberculosis showed that air-trapping was more common during treatment than in controls (12% vs 0%, respectively, p = 0.017); which improved following treatment completion. Adolescents with tuberculosis both during and after treatment completion walked a shorter distance than controls.

Interpretation

Adolescents with tuberculosis have impaired lung function even after treatment completion. It is crucial to include adolescents in trials on the prevention and treatment of tuberculosis-associated respiratory morbidity.

Funding

EDCTP, National Institute of Health, Medical Research Council, BMBF.

Vaccine development against tuberculosis before and after Covid-19

Coronavirus disease (Covid-19) has not only shaped awareness of the impact of infectious diseases on global health. It has also provided instructive lessons for better prevention strategies against new and current infectious diseases of major importance. Tuberculosis (TB) is a major current health threat caused by Mycobacterium tuberculosis (Mtb) which has claimed more lives than any other pathogen over the last few centuries. Hence, better intervention measures, notably novel vaccines, are urgently needed to accomplish the goal of the World Health Organization to end TB by 2030. This article describes how the research and development of TB vaccines can benefit from recent developments in the Covid-19 vaccine pipeline from research to clinical development and outlines how the field of TB research can pursue its own approaches. It begins with a brief discussion of major vaccine platforms in general terms followed by a short description of the most widely applied Covid-19 vaccines. Next, different vaccination regimes and particular hurdles for TB vaccine research and development are described. This specifically considers the complex immune mechanisms underlying protection and pathology in TB which involve innate as well as acquired immune mechanisms and strongly depend on fine tuning the response. A brief description of the TB vaccine candidates that have entered clinical trials follows. Finally, it discusses how experiences from Covid-19 vaccine research, development, and rollout can and have been applied to the TB vaccine pipeline, emphasizing similarities and dissimilarities.

Global burden of disease due to rifampicin-resistant tuberculosis: a mathematical modeling analysis

In 2020, almost half a million individuals developed rifampicin-resistant tuberculosis (RR-TB). We estimated the global burden of RR-TB over the lifetime of affected individuals. We synthesized data on incidence, case detection, and treatment outcomes in 192 countries (99.99% of global tuberculosis). Using a mathematical model, we projected disability-adjusted life years (DALYs) over the lifetime for individuals developing tuberculosis in 2020 stratified by country, age, sex, HIV, and rifampicin resistance. Here we show that incident RR-TB in 2020 was responsible for an estimated 6.9 (95% uncertainty interval: 5.5, 8.5) million DALYs, 44% (31, 54) of which accrued among TB survivors. We estimated an average of 17 (14, 21) DALYs per person developing RR-TB, 34% (12, 56) greater than for rifampicin-susceptible tuberculosis. RR-TB burden per 100,000 was highest in former Soviet Union countries and southern African countries. While RR-TB causes substantial short-term morbidity and mortality, nearly half of the overall disease burden of RR-TB accrues among tuberculosis survivors. The substantial long-term health impacts among those surviving RR-TB disease suggest the need for improved post-treatment care and further justify increased health expenditures to prevent RR-TB transmission.

Performance during the Glittre-ADL test between patients with and without post-tuberculosis bronchiectasis: A cross-sectional study

BACKGROUND

Post-tuberculosis bronchiectasis (PTBB) is gaining recognition as an important chronic lung disease, representing a neglected condition with a significant burden for the individual. Recently, the Glittre-ADL test (TGlittre) has been proposed for the assessment of functional capacity, which incorporates tasks of daily living demanding the upper and lower extremities. This study used TGlittre to compare patients with PTBB to patients with non-post-tuberculosis bronchiectasis (NPTBB) and evaluate the determinants of performance during TGlittre.

METHODS

This is a cross-sectional study in which 32 patients with PTBB and 29 with NPTBB underwent TGlittre. In addition, they completed Short Form-36 (SF-36), handgrip strength, quadriceps muscle strength (QMS) and pulmonary function tests (PFTs).

RESULTS

Both PTBB and NPTBB required much more time to perform the TGlittre compared to the predicted values, although they did not differ statistically from each other [152 (124-200) vs. 145 (117-179)% predicted, p = 0.41]. Regarding the PFTs, the PTBB participants showed significantly lower values than the NPTBB participants in forced vital capacity (FVC, 60 ± 14.5 vs. 78.2 ± 22.2% predicted, p<0.001) and total lung capacity [82 (66-95) vs. 93 (82-105)% predicted, p = 0.028]. In the PTBB group, FVC (p<0.001) and QMS (p = 0.001) were the only significant independent variables to predict TGlittre time, explaining 71% of the variability in TGlittre time. In the NPTBB group, maximal expiratory pressure (p = 0.002), residual volume/TLC (p = 0.001) and QMS (p = 0.032) were the significant independent variables for predicting TGlittre time, explaining 73% of the variability in TGlittre time.

CONCLUSIONS

PTBB patients have lower than expected performance on TGlittre, though similar to NPTBB patients. The PTBB patients had a greater reduction in lung volume than NPTBB patients. Furthermore, the performance on TGlittre in PTBB patients is largely explained by lung volume and QMS.

"Post tuberculosis": the urgent need for inclusion of lung health outcomes in tuberculosis treatment trials

We read with interest the systematic review by Ivanova et al. [1], recently published in the European Respiratory Review , highlighting significant long-term lung function impairment experienced by people that survive tuberculosis (TB). Lung function impairment is a well-described characteristic of post-TB lung disease (PTLD), a condition that spans the spectrum of obstructive airway disease, bronchiectasis and fibro-cavitating disease, along with fungal and other respiratory infections [2]. The pathophysiology of PTLD will also be described in detail in the ERS Monograph entitled “The Challenge of Tuberculosis in the 21st Century”.

New TB treatment regimens are a welcome advancement. However, for the millions of TB survivors with impaired lung function and quality of life, more holistic outcome measures and the inclusion of lung function is essential in future TB treatment trials. https://bit.ly/3PWT0o2

Performance of spirometry assessment at TB diagnosis

BACKGROUND: Spirometry is considered relevant for the diagnosis and monitoring of post-TB lung disease. However, spirometry is rarely done in newly diagnosed TB patients.METHODS: Newly diagnosed, microbiologically confirmed TB patients were recruited for the study. Spirometry was performed within 21 days of TB treatment initiation according to American Thoracic Society/European Respiratory Society guidelines. Spirometry analysis was done using Global Lung Initiative equations for standardisation.RESULTS: Of 1,430 eligible study participants, 24.7% (353/1,430) had no spirometry performed mainly due to contraindications and 23.0% (329/1,430) had invalid results; 52.3% (748/1,430) of participants had a valid result, 82.8% (619/748) of whom had abnormal spirometry. Of participants with abnormal spirometry, 70% (436/619) had low forced vital capacity (FVC), 6.1% (38/619) had a low ratio of forced expiratory volume in 1 sec (FEV1) to FVC, and 19.1% (118/619) had low FVC, as well as low FEV1/FVC ratio. Among those with abnormal spirometry, 26.3% (163/619) had severe lung impairment.CONCLUSIONS: In this population, a high proportion of not performed and invalid spirometry assessments was observed; this was addressed by removing tachycardia as a (relative) contraindication from the study guidance and retraining. The high proportion of patients with severe pulmonary impairment at the time of TB diagnosis suggests a huge morbidity burden and calls for further longitudinal studies on the relevance of spirometry in predicting chronic lung impairment after TB.

Mechanisms of lung damage in tuberculosis: implications for chronic obstructive pulmonary disease

Pulmonary tuberculosis is increasingly recognized as a risk factor for COPD. Severe lung function impairment has been reported in post-TB patients. Despite increasing evidence to support the association between TB and COPD, only a few studies describe the immunological basis of COPD among TB patients following successful treatment completion. In this review, we draw on well-elaborated Mycobacterium tuberculosis-induced immune mechanisms in the lungs to highlight shared mechanisms for COPD pathogenesis in the setting of tuberculosis disease. We further examine how such mechanisms could be exploited to guide COPD therapeutics.