Unit costs and cost-effectiveness of a device to improve TB treatment adherence in China.

BACKGROUND: Adherence to TB drugs is crucial for improving treatment outcomes. Digital adherence technologies can improve adherence; however, there is a lack of evidence on cost-effectiveness. This study aimed to explore the cost-effectiveness of medication event reminder monitors (MERM) in China compared with the standard of care, using results from a pragmatic, cluster-randomised superiority trial of an electronic MERM in China. METHODS: We collected primary unit cost data from the societal perspective, both at and above the health facility level. We estimated the incremental cost-effectiveness of MERM using a Markov model with a 20-year time horizon; a 3% discount rate was applied to costs and outcomes. We explored uncertainty through a series of sensitivity and scenario analyses. RESULTS: The incremental cost of MERM was $27.22 per patient. Probabilistic sensitivity analysis showed significant uncertainty about the intervention's cost-effectiveness. Changing assumptions around key parameters substantially affected our estimated incremental cost-effectiveness ratio. CONCLUSIONS: Although the incremental cost of the MERM box was low, current evidence does not indicate that the intervention would be cost-effective. However, the intervention's cost-effectiveness could improve if implemented as part of a broader strategy, including enhanced patient management.

CONTEXTE: Il est crucial de respecter les médicaments antituberculeux pour améliorer les résultats du traitement. Les technologies numériques peuvent améliorer l'observance, mais il existe un manque de preuves sur leur rapport coût-efficacité. Cette étude a examiné le rapport coût-efficacité des moniteurs de rappel d'événements médicamenteux (MERM, pour l'anglais, « medication event reminder monitors ¼) en Chine par rapport aux soins standards, en se basant sur les résultats d'un essai pragmatique randomisé en grappes d'un MERM électronique en Chine. MÉTHODES: Les coûts unitaires primaires du point de vue de la société ont été collectés et analysés à la fois au niveau de l'établissement de santé et au-delà. Pour évaluer le rapport coût-efficacité différentiel du MERM, nous avons utilisé un modèle de Markov sur une période de 20 ans, en appliquant un taux d'actualisation de 3% aux coûts et aux résultats. Afin de prendre en compte les incertitudes, nous avons effectué plusieurs analyses de sensibilité et de scénarios. RÉSULTATS: Le coût supplémentaire du MERM s'élevait à 27,22 $ par patient. L'analyse de sensibilité probabiliste a révélé une incertitude importante concernant le rapport coût-efficacité de l'intervention. La variation des hypothèses liées aux paramètres clés a eu un impact significatif sur le rapport coût-efficacité différentiel estimé. CONCLUSIONS: Bien que le coût différentiel de la boîte MERM soit faible, les données actuelles n'indiquent pas que l'intervention serait rentable. Toutefois, le rapport coût-efficacité de l'intervention pourrait être amélioré si elle était mise en œuvre dans le cadre d'une stratégie plus large, comprenant une meilleure prise en charge des patients.

Community-level variation in TB testing history in Blantyre, Malawi.

SETTING: Equitable access to TB testing is vital for achieving global diagnosis and treatment targets, but access to diagnostic services is often worse in poorer communities. The SCALE (Sustainable Community-wide Active case-finding for Lung hEalth) survey estimated TB prevalence in Blantyre City, Malawi, and recorded previous engagement with TB services.OBJECTIVE: To explore local variation in the prevalence of ever-testing for TB in Blantyre and investigate potential socio-economic drivers.DESIGN: We fit a mixed-effects model to self-reported prior TB testing from survey participants across 72 neighbourhood clusters, adjusted for sex, age and HIV status and with cluster-level random intercepts. We then evaluated to what extent cluster-level variation was explained by two alternate poverty indicators.RESULTS: We observed substantial variation between clusters in previous TB testing, with little correlation between neighbouring clusters. Individuals residing in less affluent households, on average, had lower odds of having undergone prior testing. However, adjusting for poverty did not explain the cluster-level variations observed.CONCLUSION: Despite a decade of increased active case-finding efforts, access to TB testing is inconsistent across the population of Blantyre. This likely reflects health inequities that also apply to TB testing in many other settings, and motivates collection and analysis of TB testing data to identify the drivers behind these inequities.

Delivery of TB preventive therapy to incarcerated people living with HIV in southern African correctional facilities.

TB preventive treatment (TPT) is recommended for high-risk and hard-to-reach populations such as incarcerated people living with HIV (PLHIV). To assess implementation of TPT delivery in correctional settings, we conducted an exploratory analysis of data from a multisite cohort study in South Africa and Zambia. From 975 participants, 648 were screened for TB, and 409 initiated TPT mostly within a month after initiation of antiretroviral therapy (190/409, 46.5%). We observed a median gap of one month (IQR 0.6-4.7) in TPT delivery to incarcerated PLHIV. Future research should examine standardised quality improvement tools and new strategies such as short-course regimens to improve TPT initiation in this population.

Le traitement préventif antituberculeux (TPT) est recommandé pour les populations à haut risque et difficiles à atteindre, telles que les personnes vivant avec le VIH (PLHIV) qui sont incarcérées. Afin d'évaluer la mise en place du TPT en centres correctionnels, nous avons réalisé une analyse exploratoire des données d'une étude de cohorte multisites en Afrique du Sud et en Zambie. Sur 975 participants, 648 ont subi un test de dépistage de la TB et 409 ont été mis sous TPT, dans le mois ayant suivi l'instauration du traitement antirétroviral pour la plupart (190/409 ; 46,5%). Nous avons observé un écart médian d'un mois (IQR 0,6­4,7) en matière de dispense du TPT aux PLHIV incarcérées. Les études futures devraient analyser l'utilisation d'outils standardisés d'amélioration de la qualité ainsi que de nouvelles stratégies, telles que les schémas thérapeutiques de courte durée, afin d'améliorer l'instauration du TPT dans cette population.

Comparison of small-sample standard-error corrections for generalised estimating equations in stepped wedge cluster randomised trials with a binary outcome: A simulation study.

Generalised estimating equations with the sandwich standard-error estimator provide a promising method of analysis for stepped wedge cluster randomised trials. However, they have inflated type-one error when used with a small number of clusters, which is common for stepped wedge cluster randomised trials. We present a large simulation study of binary outcomes comparing bias-corrected standard errors from Fay and Graubard; Mancl and DeRouen; Kauermann and Carroll; Morel, Bokossa, and Neerchal; and Mackinnon and White with an independent and exchangeable working correlation matrix. We constructed 95% confidence intervals using a t-distribution with degrees of freedom including clusters minus parameters (DFC-P), cluster periods minus parameters, and estimators from Fay and Graubard (DFFG), and Pan and Wall. Fay and Graubard and an approximation to Kauermann and Carroll (with simpler matrix inversion) were unbiased in a wide range of scenarios with an independent working correlation matrix and more than 12 clusters. They gave confidence intervals with close to 95% coverage with DFFG with 12 or more clusters, and DFC-P with 18 or more clusters. Both standard errors were conservative with fewer clusters. With an exchangeable working correlation matrix, approximated Kauermann and Carroll and Fay and Graubard had a small degree of under-coverage.

What causes symptoms suggestive of tuberculosis in HIV-positive people with negative initial investigations?

OBJECTIVE: To identify the causes of symptoms suggestive of tuberculosis (TB) among people living with the human immunodeficiency virus (PLHIV) in South Africa. METHODS: A consecutive sample of HIV clinic attendees with symptoms suggestive of TB (1 of cough, weight loss, fever or night sweats) at enrolment and at 3 months, and negative initial TB investigations, were systematically evaluated with standard protocols and diagnoses assigned using standard criteria. TB was 'confirmed' if Mycobacterium tuberculosis was identified within 6 months of enrolment, and 'clinical' if treatment started without microbiological confirmation. RESULTS: Among 103 participants, 50/103 were pre-antiretroviral therapy (ART) and 53/103 were on ART; respectively 68% vs. 79% were female; the median age was 35 vs. 45 years; the median CD4 count was 311 vs. 508 cells/mm³. Seventy-two (70%) had 5% measured weight loss and 50 (49%) had cough. The most common final diagnoses were weight loss due to severe food insecurity (n = 20, 19%), TB (n = 14, 14%: confirmed n = 7; clinical n = 7), other respiratory tract infection (n = 14, 14%) and post-TB lung disease (n = 9, 9%). The basis for TB diagnosis was imaging (n = 7), bacteriological confirmation from sputum (n = 4), histology, lumbar puncture and other (n = 1 each). CONCLUSION: PLHIV with persistent TB symptoms require further evaluation for TB using all available modalities, and for food insecurity in those with weight loss.

Lessons learnt conducting minimally invasive autopsies in private mortuaries as part of HIV and tuberculosis research in South Africa.

Current estimates of the burden of tuberculosis (TB) disease and cause-specific mortality in human immunodeficiency virus (HIV) positive people rely heavily on indirect methods that are less reliable for ascertaining individual-level causes of death and on mathematical models. Minimally invasive autopsy (MIA) is useful for diagnosing infectious diseases, provides a reasonable proxy for the gold standard in cause of death ascertainment (complete diagnostic autopsy) and, used routinely, could improve cause-specific mortality estimates. From our experience in performing MIAs in HIV-positive adults in private mortuaries in South Africa (during the Lesedi Kamoso Study), we describe the challenges we faced and make recommendations for the conduct of MIA in future studies or surveillance programmes, including strategies for effective communication, approaches to obtaining informed consent, risk management for staff and efficient preparation for the procedure.

Les estimations actuelles du poids de la tuberculose (TB) maladie et de la mortalité qui lui est due parmi les patients positifs à l'infection par le virus de l'immunodéficience humaine (VIH) dépendent beaucoup de méthodes indirectes, qui sont moins fiables pour vérifier les causes de décès au niveau individuel et de modèles mathématiques. Une autopsie peu invasive (MIA) est utile au diagnostic de maladies infectieuses, fournit une approximation raisonnable de l'étalon or de la vérification de la cause du décès c'est-à-dire une autopsie diagnostique complète. Si elle est utilisée en routine, elle pourrait améliorer les estimations de mortalité spécifique d'une cause. A partir de nos expériences de MIA sur des adultes positifs au VIH dans des morgues privées d'Afrique du Sud (au cours de l'étude Lesedi Kamoso), nous décrivons les défis rencontrés et faisons des recommandations pour la réalisation de MIA dans des études futures ou des programmes de surveillance, incluant des stratégies de communication efficaces, des approches visant à obtenir un consentement éclairé, une prise en charge du risque pour le personnel et une préparation efficace de la procédure.

Las estimaciones actuales de morbilidad por tuberculosis (TB) y de mortalidad por causas específicas en las personas positivas frente al virus de la inmunodeficiencia humana (VIH) se fundamentan en su mayor parte en métodos indirectos que son menos fiables para determinar las causas de muerte individuales y en modelizaciones matemáticas. La autopsia mínimamente invasiva (MIA) es útil en el diagnóstico de las enfermedades infecciosas, ofrece un sustituto aceptable al método de referencia para determinar la causa de muerte (que es la autopsia diagnóstica completa), y cuando se usa de manera sistemática, mejora las estimaciones de la mortalidad por causas específicas. A partir de su experiencia con la MIA en adultos con infección por el VIH en empresas fúnebres privadas en Suráfrica (durante el estudio Lesedi Kamoso), los autores describen las dificultades que encontraron y formulan recomendaciones que se pueden aplicar en el futuro al realizar la autopsia mínimamente invasiva en estudios de investigación o en programas de vigilancia; se preconizan estrategias de comunicación efectivas, métodos de obtención del consentimiento informado, la gestión de riesgos para el personal y la preparación eficiente del procedimiento.

Cost of point-of-care lateral flow urine lipoarabinomannan antigen testing in HIV-positive adults in South Africa.

INTRODUCTION: The World Health Organization recommends point-of-care (POC) lateral flow urine lipoarabinomannan (LF-LAM) for tuberculosis (TB) diagnosis in selected human immunodeficiency virus (HIV) positive people. South Africa had 438 000 new TB episodes in 2016, 58.9% of which were contributed by HIV-positive people. LF-LAM is being considered for scale-up in South Africa. METHODS: We estimated the costs of using LF-LAM in HIV-positive adults with CD4 counts  150 cells/µl enrolled in the TB Fast Track Trial in South Africa. We also estimated costs of POC haemoglobin (Hb), as this was used in the study algorithm. Data on clinic-level (10 intervention clinics) and above-clinic-level costs were collected. RESULTS: A total of 1307 LF-LAM tests were performed at 10 clinics over 24 months. The mean clinic-level costs were US$12.80 per patient for LF-LAM and POC Hb; LF-LAM costs were US$11.49 per patient. The mean above-clinic-level unit costs for LF-LAM were US$12.06 for clinic preparation, training, coordination and mentoring. The mean total cost of LF-LAM was US$23.55 per patient. CONCLUSION: At clinic level, the cost of LF-LAM was comparable to other TB diagnostics in South Africa. It is important to consider above-clinic-level costs for POC tests, as these may be required to support roll-out and ensure successful implementation.

An intervention to optimise the delivery of integrated tuberculosis and HIV services at primary care clinics: results of the MERGE cluster randomised trial.

OBJECTIVES: To evaluate the effect of an intervention to optimize TB/HIV integration on patient outcomes. METHODS: Cluster randomised control trial at 18 primary care clinics in South Africa. The intervention was placement of a nurse (TB/HIV integration officer) to facilitate provision of integrated TB/HIV services, and a lay health worker (TB screening officer) to facilitate TB screening for 24 months. Primary outcomes were i) incidence of hospitalisation/death among individuals newly diagnosed with HIV, ii) incidence of hospitalisation/death among individuals newly diagnosed with TB and iii) proportion of HIV-positive individuals newly diagnosed with TB who were retained in HIV care 12 months after enrolment. RESULTS: Of 3328 individuals enrolled, 3024 were in the HIV cohort, 731 in TB cohort and 427 in TB-HIV cohort. For the HIV cohort, the hospitalisation/death rate was 12.5 per 100 person-years (py) (182/1459py) in the intervention arm vs. 10.4/100py (147/1408 py) in the control arms respectively (Relative Risk (RR) 1.17 [95% CI 0.92-1.49]).For the TB cohort, hospitalisation/ death rate was 17.1/100 py (67/ 392py) vs. 11.1 /100py (32/289py) in intervention and control arms respectively (RR 1.37 [95% CI 0.78-2.43]). For the TB-HIV cohort, retention in care at 12 months was 63.0% (213/338) and 55.9% (143/256) in intervention and control arms (RR 1.11 [95% 0.89-1.38]). CONCLUSIONS: The intervention as implemented failed to improve patient outcomes beyond levels at control clinics. Effective strategies are needed to achieve better TB/HIV service integration and improve TB and HIV outcomes in primary care clinics. TRIAL REGISTRATION: South African Register of Clinical Trials (registration number DOH-27-1011-3846).

Robust analysis of stepped wedge trials using cluster-level summaries within periods.

In stepped-wedge trials (SWTs), the intervention is rolled out in a random order over more than 1 time-period. SWTs are often analysed using mixed-effects models that require strong assumptions and may be inappropriate when the number of clusters is small. We propose a non-parametric within-period method to analyse SWTs. This method estimates the intervention effect by comparing intervention and control conditions in a given period using cluster-level data corresponding to exposure. The within-period intervention effects are combined with an inverse-variance-weighted average, and permutation tests are used. We present an example and, using simulated data, compared the method to (1) a parametric cluster-level within-period method, (2) the most commonly used mixed-effects model, and (3) a more flexible mixed-effects model. We simulated scenarios where period effects were common to all clusters, and when they varied according to a distribution informed by routinely collected health data. The non-parametric within-period method provided unbiased intervention effect estimates with correct confidence-interval coverage for all scenarios. The parametric within-period method produced confidence intervals with low coverage for most scenarios. The mixed-effects models' confidence intervals had low coverage when period effects varied between clusters but had greater power than the non-parametric within-period method when period effects were common to all clusters. The non-parametric within-period method is a robust method for analysing SWT. The method could be used by trial statisticians who want to emphasise that the SWT is a randomised trial, in the common position of being uncertain about whether data will meet the assumptions necessary for mixed-effect models.

Delay in seeking care for tuberculosis symptoms among adults newly diagnosed with HIV in rural Malawi.

SETTING: Ten primary health clinics in rural Thyolo District, Malawi. OBJECTIVE: Tuberculosis (TB) is a common initial presentation of human immunodeficiency virus (HIV) infection. We investigated the time from TB symptom onset to HIV diagnosis to describe TB health-seeking behaviour in adults newly diagnosed with HIV. DESIGN: We asked adults (18 years) about the presence and duration of TB symptoms at the time of receiving a new HIV diagnosis. Associations with delayed health seeking (defined as >30 and >90 days from the onset of TB symptoms) were evaluated using multivariable logistic regression. RESULTS: TB symptoms were reported by 416 of 1265 participants (33%), of whom 36% (150/416) had been symptomatic for >30 days before HIV testing. Most participants (260/416, 63%) were below the poverty line (US$0.41 per household member per day). Patients who first sought care from informal providers had an increased odds of delay of >30 days (adjusted odds ratio [aOR] 1.6, 95%CI 0.9-2.8) or 90 days (aOR 2.0, 95%CI 1.1-3.8). CONCLUSIONS: Delayed health seeking for TB-related symptoms was common. Poverty was ubiquitous, but had no clear relationship to diagnostic delay. HIV-positive individuals who first sought care from informal providers were more likely to experience diagnostic delays for TB symptoms.

Does antiretroviral treatment increase the infectiousness of smear-positive pulmonary tuberculosis?

BACKGROUND: Understanding of the effects of human immunodeficiency virus (HIV) infection and antiretroviral treatment (ART) on Mycobacterium tuberculosis transmission dynamics remains limited. We undertook a cross-sectional study among household contacts of smear-positive pulmonary tuberculosis (TB) cases to assess the effect of established ART on the infectiousness of TB. METHOD: Prevalence of tuberculin skin test (TST) positivity was compared between contacts of index cases aged 2-10 years who were HIV-negative, HIV-positive but not on ART, on ART for <1 year and on ART for 1 year. Random-effects logistic regression was used to take into account clustering within households. RESULTS: Prevalence of M. tuberculosis infection in contacts of HIV-negative patients, HIV-positive patients on ART 1 year and HIV-positive patients not on ART/on ART <1 year index cases was respectively 44%, 21% and 22%. Compared to contacts of HIV-positive index cases not on ART or recently started on ART, the odds of TST positivity was similar in contacts of HIV-positive index cases on ART 1 year (adjusted OR [aOR] 1.0, 95%CI 0.3-3.7). The odds were 2.9 times higher in child contacts of HIV-negative index cases (aOR 2.9, 95%CI 1.0-8.2). CONCLUSIONS: We found no evidence that established ART increased the infectiousness of smear-positive, HIV-positive index cases.

Drug-resistant tuberculosis clinical trials: proposed core research definitions in adults.

Drug-resistant tuberculosis (DR-TB) is a growing public health problem, and for the first time in decades, new drugs for the treatment of this disease have been developed. These new drugs have prompted strengthened efforts in DR-TB clinical trials research, and there are now multiple ongoing and planned DR-TB clinical trials. To facilitate comparability and maximise policy impact, a common set of core research definitions is needed, and this paper presents a core set of efficacy and safety definitions as well as other important considerations in DR-TB clinical trials work. To elaborate these definitions, a search of clinical trials registries, published manuscripts and conference proceedings was undertaken to identify groups conducting trials of new regimens for the treatment of DR-TB. Individuals from these groups developed the core set of definitions presented here. Further work is needed to validate and assess the utility of these definitions but they represent an important first step to ensure there is comparability in clinical trials on multidrug-resistant TB.

Risk factors for Mycobacterium tuberculosis infection in 2-4 year olds in a rural HIV-prevalent setting.

BACKGROUND: Mycobacterium tuberculosis infection in children acts as a sentinel for infectious tuberculosis. OBJECTIVE: To assess risk factors associated with tuberculous infection in pre-school children. METHOD: We conducted a population-wide tuberculin skin test (TST) survey from January to December 2012 in Malawi. All children aged 2-4 years residing in a demographic surveillance area were eligible. Detailed demographic data, including adult human immunodeficiency virus (HIV) status, and clinical and sociodemographic data on all diagnosed tuberculosis (TB) patients were available. RESULTS: The prevalence of M. tuberculosis infection was 1.1% using a TST induration cut-off of 15 mm (estimated annual risk of infection of 0.3%). The main identifiable risk factors were maternal HIV infection at birth (adjusted OR [aOR] 3.6, 95%CI 1.1-12.2), having three or more adult members in the household over a lifetime (aOR 2.4, 95%CI 1.2-4.8) and living in close proximity to a known case of infectious TB (aOR 1.6, 95%CI 1.1-2.4), modelled as a linear variable across categories (>200 m, 100-200 m, <100 m, within household). Less than 20% of the infected children lived within 200 m of a known diagnosed case. CONCLUSION: Household and community risk factors identified do not explain the majority of M. tuberculosis infections in children in our setting.

Implementation and Operational Research: What Happens After a Negative Test for Tuberculosis? Evaluating Adherence to TB Diagnostic Algorithms in South African Primary Health Clinics.

INTRODUCTION AND BACKGROUND: Diagnostic tests for tuberculosis (TB) using sputum have suboptimal sensitivity among HIV-positive persons. We assessed health care worker adherence to TB diagnostic algorithms after negative sputum test results. METHODS: The XTEND (Xpert for TB-Evaluating a New Diagnostic) trial compared outcomes among people tested for TB in primary care clinics using Xpert MTB/RIF vs. smear microscopy as the initial test. We analyzed data from XTEND participants who were HIV positive or HIV status unknown, whose initial sputum Xpert MTB/RIF or microscopy result was negative. If chest radiography, sputum culture, or hospital referral took place, the algorithm for TB diagnosis was considered followed. Analysis of intervention (Xpert MTB/RIF) effect on algorithm adherence used methods for cluster-randomized trials with small number of clusters. RESULTS: Among 4037 XTEND participants with initial negative test results, 2155 (53%) reported being or testing HIV positive and 540 (14%) had unknown HIV status. Among 2155 HIV-positive participants [684 (32%) male, mean age 37 years (range, 18-79 years)], there was evidence of algorithm adherence among 515 (24%). Adherence was less likely among persons tested initially with Xpert MTB/RIF vs. smear [14% (142/1031) vs. 32% (364/1122), adjusted risk ratio 0.34 (95% CI: 0.17 to 0.65)] and for participants with unknown vs. positive HIV status [59/540 (11%) vs. 507/2155 (24%)]. CONCLUSIONS: We observed poorer adherence to TB diagnostic algorithms among HIV-positive persons tested initially with Xpert MTB/RIF vs. microscopy. Poor adherence to TB diagnostic algorithms and incomplete coverage of HIV testing represents a missed opportunity to diagnose TB and HIV, and may contribute to TB mortality.

Accelerating progress towards tuberculosis elimination: the need for combination treatment and prevention.

Although estimated tuberculosis (TB) incidence is now falling globally, we are unlikely to achieve the Millennium Development Goal (MDG) TB targets without changing the emphasis of the global TB response in high human immunodeficiency virus prevalence settings. Two independent modelling exercises using South African data with different structures and assumptions conclude that, until new drugs, diagnostics and vaccines are available, a fully funded and accessible combination approach to anti-tuberculosis treatment and prevention, based on knowledge of local TB epidemiology and evidence-informed policy, is essential to accelerate progress towards zero new tuberculous infections, zero TB deaths and zero suffering from TB.

A cluster randomised trial to evaluate the effect of optimising TB/HIV integration on patient level outcomes: the "merge" trial protocol.

INTRODUCTION: We describe the design of the MERGE trial, a cluster randomised trial, to evaluate the effect of an intervention to optimise TB/HIV service integration on mortality, morbidity and retention in care among newly-diagnosed HIV-positive patients and newly-diagnosed TB patients. DESIGN: Eighteen primary care clinics were randomised to either intervention or standard of care arms. The intervention comprised activities designed to optimise TB and HIV service integration and supported by two new staff cadres-a TB/HIV integration officer and a TB screening officer-for 24 months. A process evaluation to understand how the intervention was perceived and implemented at the clinics was conducted as part of the trial. Newly-diagnosed HIV-positive patients and newly-diagnosed TB patients were enrolled into the study and followed up through telephonic interviews and case note abstractions at six monthly intervals for up to 18 months in order to measure outcomes. The primary outcomes were incidence of hospitalisations or death among newly diagnosed TB patients, incidence of hospitalisation or death among newly diagnosed HIV-positive patients and retention in care among HIV-positive TB patients. Secondary outcomes of the study included measures of cost-effectiveness. DISCUSSION: Methodological challenges of the trial such as implementation of a complex multi-faceted health systems intervention, the measurement of integration at baseline and at the end of the study and an evolving standard of care with respect to TB and HIV are discussed. The trial will contribute to understanding whether TB/HIV service integration affects patient outcomes.

Spectrum of non-tuberculous mycobacteria identified using standard biochemical testing vs. 16S sequencing.

Non-tuberculous mycobacterial isolates from gold miners were speciated using standard biochemical testing (SBT) and 16S rDNA sequencing. Of 237 isolates tested, SBT identified 126, compared with all 237 identified using sequencing. Of 111 isolates unspeciated by SBT but identified by sequencing, 38 (34.2%) were identified as Mycobacterium gordonae and 8 (7.2%) were new species. Of 126 isolates speciated by both methods, 37 were discordant, with 14/17 M. gordonae isolates incorrectly identified as M. scrofulaceum using SBT. The majority of these were the potentially pathogenic strain D, M. gordonae. Sequencing is preferable where available to guide treatment.

The measurement of household socio-economic position in tuberculosis prevalence surveys: a sensitivity analysis.

OBJECTIVE: To assess the robustness of socio-economic inequalities in tuberculosis (TB) prevalence surveys. DESIGN: Data were drawn from the TB prevalence survey conducted in Lusaka Province, Zambia, in 2005-2006. We compared TB socio-economic inequalities measured through an asset-based index (Index 0) using principal component analysis (PCA) with those observed using three alternative indices: Index 1 and Index 2 accounted respectively for the biases resulting from the inclusion of urban assets and food-related variables in Index 0. Index 3 was built using regression-based analysis instead of PCA to account for the effect of using a different assets weighting strategy. RESULTS: Household socio-economic position (SEP) was significantly associated with prevalent TB, regardless of the index used; however, the magnitude of inequalities did vary across indices. A strong association was found for Index 2, suggesting that the exclusion of food-related variables did not reduce the extent of association between SEP and prevalent TB. The weakest association was found for Index 1, indicating that the exclusion of urban assets did not lead to higher extent of TB inequalities. CONCLUSION: TB socio-economic inequalities seem to be robust to the choice of SEP indicator. The epidemiological meaning of the different extent of TB inequalities is unclear. Further studies are needed to confirm our conclusions.