Review of multidrug-resistant and extensively drug-resistant TB: global perspectives with a focus on sub-Saharan Africa

Tuberculosis (TB) remains a global emergency and is responsible for 1.7 million deaths annually. Widespread global misuse of isoniazid and rifampicin over three decades has resulted in emergence of the ominous spread of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) globally. These difficult to treat resistant forms of TB are increasingly seen in Asia, Eastern Europe, South America and sub-Saharan Africa, disrupting TB and HIV control programmes. We review the latest available global epidemiological and clinical evidence on drug-resistant TB in HIV-infected and uninfected populations, with focus on Africa where data are scanty because of poor diagnostic and reporting facilities. The difficult management and infection control problems posed by drug-resistant TB in HIV-infected patients are discussed. Given the increasing current global trends in MDR-TB, aggressive preventive and management strategies are urgently required to avoid disruption of global TB control efforts. The data suggest that existing interventions, public health systems and TB and HIV programmes must be strengthened significantly. Political and funder commitment is essential to curb the spread of drug-resistant TB

Global Financing and Long-Term Technical Assistance for Multidrug-Resistant Tuberculosis: Scaling Up Access to Treatment

Thomas Hwang and Salmaan Keshavjee argue that a market-based strategy combined with long-term in-country technical assistance should be used to scale-up access to the treatment of multi-drug resistant tuberculosis Please see later in the article for the Editors' Summar

Randomized Trials to Optimize Treatment of Multidrug-Resistant Tuberculosis: The time for action is now

The time is now right for randomized trials of MDR-TB, say the authors, as the expansion of MDR-TB programs provides the setting in which trials can be implemented

Timely treatment initiation of free drug-resistant tuberculosis care in Nigeria? : a mixed methods study of patient experience, socio-demographic characteristics and health system factors

Introduction: Au Nigeria, la couverture de la détection et du traitement de la tuberculose pharmaco-résistante (TPR) est toujours faible malgré la mise en place de services gratuits depuis 2011. Le pays se classe au sixième rang mondial avec une proportion de cas de patients résistants aux médicaments de 4,3% et de 15% dans les cas d’une réinitialisation au traitement. Le pays a aussi un fardeau élevé pour la tuberculose, la TPR, et le VIH, avec une prévalence de 219 et 11 pour 100 000 habitants pour la tuberculose et la TPR et de 1,28 pour 1 000 habitants pour le VIH. Sans traitement, la mortalité due à la tuberculose est d'environ 70% en dix ans, augmentant avec la coïnfection par le VIH, et la résistance aux médicaments; et descendant en dessous de 5% avec traitement. Les taux de survie de la tuberculose pharmaco-résistante sont plus faibles et le traitement est plus long, plus coûteux et plus toxique. Cela peut poser des défis différents à la fois pour les patients et les systèmes de santé comparativement à la tuberculose de la forme commune. Cependant, la réponse au traitement et la survie sont influencées par la détection précoce et à l'initiation rapide au traitement, idéalement dans les quatre semaines suivant le diagnostic, en particulier avec la coïnfection par le VIH. Les caractéristiques sociodémographiques interagissent souvent de manière complexe avec des facteurs systémiques, pour accroître la vulnérabilité et les désavantages - ces interactions sont particulièrement bien examinées à travers un cadre conceptuel d'équité à l'accès à la santé, et pourrait offrir des analyses et des recommandations pertinentes pour les politiques. Cette thèse explore les barrières et les facilitateurs à l’accès au diagnostic et au traitement au niveau des patients et du système de santé au Nigéria. Méthodes: Cette thèse est une étude transformative de méthodes mixtes. Nous avons d’abord réalisé une revue systématique mixte pour identifier les obstacles et les facilitateurs influençant l’accès au diagnostic et au traitement de la TPR en Afrique subsaharienne. Nous avons par la suite mené une méta-synthèse qualitative pour examiner en profondeur les obstacles aux soins de la tuberculose auxquels se heurtent les patients, la communauté, et le système de santé. Nous avons utilisé les résultats des deux revues systématiques pour affiner notre cadre conceptuel afin d'orienter la conception et l'analyse de l'étude empirique qui a suivi. Le cadre conceptuel adapté est basé sur le cadre de Levesque. Ce cadre centré sur les patients conceptualise l’accès aux soins selon des dimensions du système de santé et des patients. Cette étude comprenait également une analyse rétrospective d’une cohorte de patients diagnostiqués en 2015 (n = 996) à l'aide de données secondaires nationales et une analyse en cascade des soins de la tuberculose pharmaco-résistante entre 2013 et 2017. Nous avons mené des analyses statistiques descriptives et analytiques. Nous avons effectué une régression logistique et d'autres tests d’association pour mesurer la relation entre les variables catégorielles. L’étude qualitative était une étude de cas qui consistait à examiner la dynamique de soins du point de vue des patients (n = 86 participants, n = 7 groupes de discussions, 5 entretiens approfondis avec des patients diagnostiqués et non traités), leurs familles (n = 19 participants, n = 1 groupe de discussion, 7entretiens approfondis ), membres de la communauté (n = 23 , n=2 groupes de discussion), agents de santé (n = 5 entretiens approfondis) et gestionnaires de programme (n = 29 entretiens approfondis) dans quatre États du Nigéria. Nous avons analysé nos données qualitatives à l'aide d'une analyse thématique. Résultats: Notre revue systématique mixte et notre méta-synthèse qualitative ont indiqué des obstacles et des facilitateurs à l’accès aux soins de la tuberculose pharmaco-résistante au niveau du système de santé et des patients. Les problèmes de fonctionnement des laboratoires et des cliniques, l’absence de connaissances et les attitudes des prestataires de soins, et la gestion de l'information étaient des obstacles à l’accès aux soins de la TPR. Les facteurs facilitateurs comprenaient des outils de diagnostic plus récents, la décentralisation des services et le coût gratuit des soins. Au niveau des patients, la perte de suivi avant ou pendant les soins en raison de la perception négative des soins dans les services publics, le genre, la famille, l’engagement professionnel ou scolaire, et le recours aux soins dans le secteur privé constituaient des obstacles. Les facilitateurs étaient la séropositivité pour VIH, la multitude de symptômes, et le soutien financier des patients. Nos résultats quantitatifs ont révélé une certaine amélioration mais des progrès insuffisants dans le diagnostic et la couverture du traitement au Nigeria entre 2013 et 2017. Notre analyse en cascade a montré des abandons significatifs entre chaque étape des soins, en commençant par les tests et en terminant par l'achèvement du traitement. En moyenne, 80% des cas estimés n'ont pas eu accès au test; 75% de ceux qui ont été testé n'ont pas été diagnostiqués; 36% des personnes diagnostiquées n'ont pas commencé le traitement et 23% d'entre elles n'ont pas terminé le traitement pour la période entre 2013-2017. En 2015, les patients et les enfants atteints de la TB qui résident au nord du Nigéria avaient une probabilité de 0,3 [IC à 95% 0,1-0,7] et 0,4[0,3-0,5] de terminer le traitement une fois la maladie diagnostiquée comparativement aux patients et aux enfants qui résident au sud du pays. Les hommes avaient une probabilité de 1,34 [IC à 95% 1,0-1,7] plus élevée de terminer le traitement après le diagnostic comparativement aux femmes. La localisation géographique et les niveaux de soins étaient associés à un traitement et / ou à un traitement rapide. Notre étude qualitative a identifié des obstacles aux soins aux niveaux individuel, familial, communautaire, et du système de santé. Certains groupes sociodémographiques de patients avaient un accès inéquitable aux soins de la TPR. Alors que les patients étaient pour la plupart traités de manière égale au niveau de l'établissement, certains patients avaient plus de difficulté à accéder aux soins en fonction de leur sexe, de leur âge, de leur profession, de leur niveau d'éducation, et de leur religion. La dynamique familiale et conjugale influencent l’accès aux soins des patients, en particulier des enfants et des femmes. Elle agissait parfois comme un obstacle aux soins. D’autres facteurs qui ont probablement entravé l’accès incluaient l’absence de considérations sur les droits d’accès et la protection des patients dans les directives de traitement et les protocoles de soins. Les patients ignoraient pour la plupart les causes de la tuberculose pharmaco-résistante et la disponibilité des soins gratuits. Le nombre d'agents de santé et les problèmes de formation, la faible performance des laboratoires et des cliniques sont des obstacles aux soins de la tuberculose au niveau du système de santé. Les principaux facilitateurs à l’accès aux soins comprenaient le soutien familial, le soutien financier aux patients et le traitement gratuit. Conclusions: Malgré la gratuité des tests et des traitements de la TB pharmaco-résistante au Nigéria depuis 2011, les couvertures de diagnostic et de traitement restent constamment faibles. Les obstacles à l’accès au diagnostic et au traitement de la TB et de la TB pharmaco-résistante sont similaires. Toutefois, la TB pharmaco-résistante présente des défis particuliers en raison de la complexité des procédures de prétraitement et des toxicités résultant des médicaments eux-mêmes. Notre étude avait pour objectif de mieux comprendre les facteurs qui influencent l’accès à l'initiation au traitement de la TB pharmaco-résistante. Nos résultats montrent que les obstacles les plus importants sont l'accès aux tests et au diagnostic, malgré les progrès technologiques de diagnostic et des protocoles cliniques. Notre étude a identifié plusieurs obstacles liés aux patients et au système de santé. La plupart des patients atteints de TB pharmaco-résistante n'ont pas accès aux tests et ne sont pas diagnostiqués, souvent en raison d'un manque d'information. Les politiques et les programmes de lutte contre la tuberculose pharmaco-résistante ne sont pas toujours équitables, en particulier pour les populations vivant dans les zones rurales, les enfants, et les femmes. Les résultats de notre étude ont généré des données probantes pertinentes pour les décideurs et les partenaires internationaux pour remédier aux disparités systémiques et fournir des services plus équitables. L'élimination des obstacles à l’accès aux soins en temps opportun devrait être une priorité urgente pour améliorer le programme de lutte contre la tuberculose au Nigéria. Dans la faible détection des cas et la couverture thérapeutique, les interventions devraient viser l'équité en facilitant l’accès aux soins des populations vulnérables.Background: Detection and treatment coverage for drug-resistant tuberculosis (DR-TB) in Nigeria are persistently low despite the implementation of free diagnostic and treatment services since 2011. Nigeria has a high burden for tuberculosis, ranking 6th globally with 4.3% drug resistance in new, and 15% in retreatment cases. The World Health Organization classifies the country as a high burden for TB, DR-TB, and HIV, with a prevalence of 219 and 11 per 100,000 population for TB and DR-TB, and 1.28 per 1,000 population HIV. Without treatment, mortality from tuberculosis is approximately 70% within ten years, increasing with HIV co-infection and drug resistance - and decreasing to below 5% with treatment. DR-TB survival rates are lower, and treatment is longer, costlier, and more toxic; this may pose different challenges to both patients and health systems than is the case for drug-sensitive (DS-) TB. However, treatment response and survival are positively impacted by early detection and treatment initiation, ideally within four weeks of diagnosis, especially with HIV co-infection. Socio-demographic characteristics often interact in complex ways with systemic factors, to increase vulnerability and disadvantage – these interactions are particularly well examined through an equity of health access framework and could offer policy-relevant analyses and recommendations. This study explores patient and health system barriers and facilitators to diagnosis and treatment for DR-TB in Nigeria. Methods: This is a sequential transformative mixed-methods study. First, a mixed-methods systematic review identified barriers and facilitators affecting diagnosis and treatment for DR-TB in sub-Saharan Africa. A subsequent qualitative meta-synthesis was used to examine in more depth the patient, community, and health system barriers to TB care. The results of the systematic reviews were used to refine our conceptual framework and to guide the design and the analysis of the subsequent empirical study. The adapted conceptual framework is based on the Levesque framework for patient-centred healthcare access, which conceptualises access to care as having health system and patient dimensions. This study also included a retrospective cohort analysis of patients diagnosed in 2015 (n= 996 ) using National secondary data, and a DR-TB care cascade analysis of the period between 2013 and 2017. We used descriptive statistics, logistic regression and other tests of association to measure the relationship between variables categorical. The qualitative phase used a case study design to examine the dynamics of care from patients' perspectives (n= 86 participants, N= 7 focus group discussions (FGD), 5 in-depth interviews (IDIs) with diagnosed and untreated patients), their relatives (n= 19 participants, N= 1 FGD, 7 IDIs ), community members (n=23 in 2 FGDs), healthcare workers (n= 5 IDIs ), and program managers (n= 29 IDIs) in four States in Nigeria. We analysed our qualitative data using thematic analysis. Results: Our mixed methods systematic review and qualitative meta-synthesis revealed barriers and facilitators to DR-TB care at the health system and patient levels. Health system laboratory and clinic operational issues, poor provider knowledge and attitudes and information management were some barriers. Facilitators included newer diagnostic tools, decentralisation of services and free cost of care. At the patient level, loss to follow-up before or during care due to negative public sector care perceptions, gender, family, work or school commitments and using private sector care were some barriers. Facilitators were HIV positivity, having more symptoms, and financial support. Our quantitative findings revealed some improvement but inadequate progress in diagnosis and treatment coverage in Nigeria between 2013 and 2017. Our cascade analysis showed significant dropouts between each stage of care, starting with testing and ending with treatment completion. On average, between 2013-2017, 80% of estimated cases did not access testing; 75% of those who test were not diagnosed; 36% of those diagnosed were not initiated on treatment and 23% of these did not finish treatment. In 2015, children and patients in Northern Nigeria had odds of 0.3 [95% CI 0.1-0.7] and 0.4 [0.3-0.5] of completing treatment once diagnosed; compared with adults and patients in Southern Nigeria; while males were shown to have a 1.34 [95% CI 1.0-1.7] times greater chance of completing treatment after diagnosis compared to females.. Geographic locations and levels of care were associated with ever receiving treatment and or timely treatment. Our qualitative data and document review identified barriers to care at individual, family, community, and health systems levels. Some patient socio-demographic groups had inequitable access. While patients were mostly treated equally at the facility level, some patients experienced more difficulty accessing care based on their gender, age, occupation, educational level and religion. Parental and spousal influences affected patients, particularly children, and women, and were sometimes barriers to care. Other factors that likely hampered access include the absence of considerations for patients’ access rights and protection in the treatment guidelines and workers manuals. Patients were mostly unaware of the causes of DR-TB disease and the availability of free care. Health worker numbers and training, clinic, and operational laboratory issues limited patients’ access at the health system level. The main facilitators to care included family support, patient financial support, and free treatment. Conclusions: Despite the provision of free DR-TB testing and treatment in Nigeria since 2011, coverage for diagnosis and treatment remain persistently low. Our literature review identified many of the same access factors affecting both DS-TB and DR-TB. However, DR-TB had peculiar challenges due to complexities in pre- treatment procedures, and in toxicities as a result of the medications themselves. This study was designed to investigate the access factors impacting DR-TB treatment initiation identified in literature. However, our findings showed that the biggest barriers to DR-TB care were essentially in access to testing and diagnosis, making any advances in diagnostic technology and treatment regimens of little benefit to DR-TB patients in Nigeria. Several patient and health system factors were shown to impede access to DR-TB care, particularly for certain groups of patients. Most DR-TB patients are not accessing testing and do not get diagnosed, often due to a lack of information. Also, DR-TB policies, structures and processes are not always equitable, especially for rural dwellers, children and women. Findings from our mixed methods study provided the additional insights needed by policymakers and implementing partners to address systemic disparities and provide more equitable services based on the population's needs. Eliminating barriers that negatively impact timely access to care should be an urgent priority for the TB program in Nigeria. In Nigeria's low case-finding and treatment coverage, interventions should target equity and ease of access, specifically for the barriers identified at the patient and health system levels

Tuberculosis diagnostics and biomarkers: needs, challenges, recent advances, and opportunities

Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics

Tuberculosis

Asserts that despite progress in controlling tuberculosis (TB), the decline in incidence has been disappointing, pointing to the need for new strategies and more effective tools. HIV/AIDS is one factor that challenges effective control of TB, especially in Southern African countries. Three key elements are needed to achieve effective TB control and to meet the Sustainable Development Goals: (1) early and accurate diagnosis and drug-sensitivity testing, (2) patient access to and completion of effective treatment, and (3) prevention of progression from latent infection to disease. Prevention requires vaccination and screening of individual at high risk as well as interventions such as air disinfection and the use of masks and respirators in hospitals and other congregate settings. Recommendations stress the need to strengthen health systems in high-burden countries by emphasizing community-based care over hospital care; to improve information systems to ensure patient adherence and manage medication supply chains; and to invest in research to develop the necessary interventions. Fundamentally, current global TB control strategies must undergo revision and receive significant research funding

Point of care tests for tuberculosis (TB) : economic analysis report

A number of clinical/disease areas have been prioritised by the TSB and DH for the DIIA Innovation Platform. To support commissioning of technology developments in the area of tuberculosis detection in humans, a scoping review has been undertaken to help identify the specific requirements for new diagnostic test development and likely payback in the area of point of care (POC) tuberculosis tests in the UK. There has been a gradual rise in the number of tuberculosis (TB) cases observed in the UK over the last 20 years, with a 4.2% rise in 2009 giving an overall 9,040 TB cases diagnosed or 15 cases per 100,000 population [1]. The aims of this economic review are to identify available information on the following for tuberculosis (TB): - economic burden of disease in the UK; - current NHS cost of TB detection and cost of treating identified TB cases; - evidence on cost-effectiveness of current tests for detection of active and latent TB infection; and - estimates of the economic benefits which new POC tests might provide in the UK

Multidrug-Resistant Tuberculosis Outbreak among US-bound Hmong Refugees, Thailand, 2005

Enhanced pre-immigration screening and program expansion decreased TB importation

Microscopic-observation drug-susceptibility assay for the diagnosis of TB.

BACKGROUND: New diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid, sensitive detection of tuberculosis and multidrug-resistant tuberculosis in sputum has been demonstrated in proof-of-principle studies of the microscopic-observation drug-susceptibility (MODS) assay, in which broth cultures are examined microscopically to detect characteristic growth. METHODS: In an operational setting in Peru, we investigated the performance of the MODS assay for culture and drug-susceptibility testing in three target groups: unselected patients with suspected tuberculosis, prescreened patients at high risk for tuberculosis or multidrug-resistant tuberculosis, and unselected hospitalized patients infected with the human immunodeficiency virus. We compared the MODS assay head-to-head with two reference methods: automated mycobacterial culture and culture on Löwenstein-Jensen medium with the proportion method. RESULTS: Of 3760 sputum samples, 401 (10.7%) yielded cultures positive for Mycobacterium tuberculosis. Sensitivity of detection was 97.8% for MODS culture, 89.0% for automated mycobacterial culture, and 84.0% for Löwenstein-Jensen culture (P<0.001); the median time to culture positivity was 7 days, 13 days, and 26 days, respectively (P<0.001), and the median time to the results of susceptibility tests was 7 days, 22 days, and 68 days, respectively. The incremental benefit of a second MODS culture was minimal, particularly in patients at high risk for tuberculosis or multidrug-resistant tuberculosis. Agreement between MODS and the reference standard for susceptibility was 100% for rifampin, 97% for isoniazid, 99% for rifampin and isoniazid (combined results for multidrug resistance), 95% for ethambutol, and 92% for streptomycin (kappa values, 1.0, 0.89, 0.93, 0.71, and 0.72, respectively). CONCLUSIONS: A single MODS culture of a sputum sample offers more rapid and sensitive detection of tuberculosis and multidrug-resistant tuberculosis than the existing gold-standard methods used

Clinical Prediction Rule for Stratifying Risk of Pulmonary Multidrug-Resistant Tuberculosis

Multidrug-resistant tuberculosis (MDR-TB), resistance to at least isoniazid and rifampin, is a worldwide problem.To develop a clinical prediction rule to stratify risk for MDR-TB among patients with pulmonary tuberculosis.Derivation and internal validation of the rule among adult patients prospectively recruited from 37 health centers (Perú), either a) presenting with a positive acid-fast bacillus smear, or b) had failed therapy or had a relapse within the first 12 months.Among 964 patients, 82 had MDR-TB (prevalence, 8.5%). Variables included were MDR-TB contact within the family, previous tuberculosis, cavitary radiologic pattern, and abnormal lung exam. The area under the receiver-operating curve (AUROC) was 0.76. Selecting a cut-off score of one or greater resulted in a sensitivity of 72.6%, specificity of 62.8%, likelihood ratio (LR) positive of 1.95, and LR negative of 0.44. Similarly, selecting a cut-off score of two or greater resulted in a sensitivity of 60.8%, specificity of 87.5%, LR positive of 4.85, and LR negative of 0.45. Finally, selecting a cut-off score of three or greater resulted in a sensitivity of 45.1%, specificity of 95.3%, LR positive of 9.56, and LR negative of 0.58.A simple clinical prediction rule at presentation can stratify risk for MDR-TB. If further validated, the rule could be used for management decisions in resource-limited areas