Solicited Cough Sound Analysis for Tuberculosis Triage Testing: The CODA TB DREAM Challenge Dataset

Cough is a common and commonly ignored symptom of lung disease. Cough is often perceived as difficult to quantify, frequently self-limiting, and non-specific. However, cough has a central role in the clinical detection of many lung diseases including tuberculosis (TB), which remains the leading infectious disease killer worldwide. TB screening currently relies on self-reported cough which fails to meet the World Health Organization (WHO) accuracy targets for a TB triage test. Artificial intelligence (AI) models based on cough sound have been developed for several respiratory conditions, with limited work being done in TB. To support the development of an accurate, point-of-care cough-based triage tool for TB, we have compiled a large multi-country database of cough sounds from individuals being evaluated for TB. The dataset includes more than 700,000 cough sounds from 2,143 individuals with detailed demographic, clinical and microbiologic diagnostic information. We aim to empower researchers in the development of cough sound analysis models to improve TB diagnosis, where innovative approaches are critically needed to end this long-standing pandemic.

Evaluation of the Xpert MTB Host Response assay for the triage of patients with presumed pulmonary tuberculosis: a prospective diagnostic accuracy study in Viet Nam, India, the Philippines, Uganda, and South Africa

BACKGROUND

Non-sputum-based triage tests for tuberculosis are a priority for ending tuberculosis. We aimed to evaluate the diagnostic accuracy of the late-prototype Xpert MTB Host Response (Xpert HR) blood-based assay.

METHODS

We conducted a prospective diagnostic accuracy study among outpatients with presumed tuberculosis in outpatient clinics in Viet Nam, India, the Philippines, Uganda, and South Africa. Eligible participants were aged 18 years or older and reported cough lasting at least 2 weeks. We excluded those receiving tuberculosis treatment in the preceding 12 months and those who were unwilling to consent. Xpert HR was performed on capillary or venous blood. Reference standard testing included sputum Xpert MTB/RIF Ultra and mycobacterial culture. We performed receiver operating characteristic (ROC) analysis to identify the optimal cutoff value for the Xpert HR to achieve the target sensitivity of 90% or more while maximising specificity, then calculated diagnostic accuracy using this cutoff value. This study was prospectively registered with ClinicalTrials.gov, NCT04923958.

FINDINGS

Between July 13, 2021, and Aug 15, 2022, 2046 adults with at least 2 weeks of cough were identified, of whom 1499 adults (686 [45·8%] females and 813 [54·2%] males) had valid Xpert HR and reference standard results. 329 (21·9%) had microbiologically confirmed tuberculosis. Xpert HR had an area under the ROC curve of 0·89 (95% CI 0·86-0·91). The optimal cutoff value was less than or equal to -1·25, giving a sensitivity of 90·3% (95% CI 86·5-93·3; 297 of 329) and a specificity of 62·6% (95% CI 59·7-65·3; 732 of 1170). Sensitivity was similar across countries, by sex, and by subgroups, although specificity was lower in people living with HIV (45·1%, 95% CI 37·8-52·6) than in those not living with HIV (65·9%, 62·8-68·8; difference of 20·8%, 95% CI 13·0-28·6; p<0·0001). Xpert HR had high negative predictive value (95·8%, 95% CI 94·1-97·1), but positive predictive value was only 40·1% (95% CI 36·8-44·1). Using the Xpert HR as a triage test would have reduced confirmatory sputum testing by 57·3% (95% CI 54·2-60·4).

INTERPRETATION

Xpert HR did not meet WHO minimum specificity targets for a non-sputum-based triage test for pulmonary tuberculosis. Despite promise as a rule-out test that could reduce confirmatory sputum testing, further cost-effectiveness modelling and data on acceptability and usability are needed to inform policy recommendations.

FUNDING

National Institute of Allergy and Infectious Diseases of the US National Institutes of Health.

TRANSLATIONS

For the Vietnamese and Tagalog translations of the abstract see Supplementary Materials section.

Lung Cancer Screening in Asia: An Expert Consensus Report

INTRODUCTION

The incidence and mortality of lung cancer are highest in Asia compared with Europe and USA, with the incidence and mortality rates being 34.4 and 28.1 per 100,000 respectively in East Asia. Diagnosing lung cancer at early stages makes the disease amenable to curative treatment and reduces mortality. In some areas in Asia, limited availability of robust diagnostic tools and treatment modalities, along with variations in specific health care investment and policies, make it necessary to have a more specific approach for screening, early detection, diagnosis, and treatment of patients with lung cancer in Asia compared with the West.

METHOD

A group of 19 advisors across different specialties from 11 Asian countries, met on a virtual Steering Committee meeting, to discuss and recommend the most affordable and accessible lung cancer screening modalities and their implementation, for the Asian population.

RESULTS

Significant risk factors identified for lung cancer in smokers in Asia include age 50 to 75 years and smoking history of more than or equal to 20 pack-years. Family history is the most common risk factor for nonsmokers. Low-dose computed tomography screening is recommended once a year for patients with screening-detected abnormality and persistent exposure to risk factors. However, for high-risk heavy smokers and nonsmokers with risk factors, reassessment scans are recommended at an initial interval of 6 to 12 months with subsequent lengthening of reassessment intervals, and it should be stopped in patients more than 80 years of age or are unable or unwilling to undergo curative treatment.

CONCLUSIONS

Asian countries face several challenges in implementing low-dose computed tomography screening, such as economic limitations, lack of efforts for early detection, and lack of specific government programs. Various strategies are suggested to overcome these challenges in Asia.

Smoking behaviour, tobacco sales and tobacco advertising at 40 'Smoke Free Hospitals' in Vietnam

BACKGROUND

Tobacco remains the leading cause of preventable death globally. Vietnam's 2012 Law on Prevention and Control of Tobacco Harms establishes all healthcare facilities as smoke-free environments. We aimed to evaluate the implementation of these policies within health facilities across Vietnam.

METHODS

A cross-sectional study was undertaken at 40 central, provincial, district and commune healthcare facilities in four provinces of Vietnam. The presence of tobacco sales, smoke-free signage, evidence of recent tobacco use and smoking behaviours by patients and staff were observed over a 1-week period at multiple locations within each facility. Adherence with national regulations was reported using descriptive statistics.

RESULTS

23 out of 40 facilities (57.5%) followed the requirements of the national smoke-free policy regarding tobacco sales, advertising and signage. Smoking was observed within health facility grounds at 26 (65%) facilities during the observation period. Indirect evidence of smoking was observed at 35 (88%) facilities. Sites where smoking was permitted (n=2) were more likely to have observed smoking behaviour (relative risk (RR) 2.16, 95% CI 1.83 to 2.56). Facilities where tobacco was sold (n=7) were more likely to have smoking behaviour observed at any of their sites (RR 1.53, 95% CI 0.93 to 2.51).

CONCLUSIONS

Implementation of current smoke-free hospital regulations remains incomplete, with widespread evidence of smoking observed at three levels of the Vietnamese healthcare facilities. Further interventions are required to establish the reputation of Vietnamese healthcare facilities as smoke-free environments.

A Standardized Approach for Collection of Objective Data to Support Outcome Determination for Late-Phase Tuberculosis Clinical Trials

Rationale: We developed a standardized method, possible poor treatment response (PPTR), to help ascertain efficacy endpoints in Study S31/A5349 (NCT02410772), an open-label trial comparing two 4-month rifapentine-based regimens with a standard 6-month regimen for the treatment of pulmonary tuberculosis (TB). Objectives: We describe the use of the PPTR process and evaluate whether the goals of minimizing bias in efficacy endpoint assessment and attainment of relevant data to determine outcomes for all participants were achieved. Methods: A PPTR event was defined as the occurrence of one or more prespecified triggers. Each PPTR required initiation of a standardized evaluation process that included obtaining multiple sputum samples for microbiology. Measurements and Main Results: Among 2,343 participants with culture-confirmed drug-susceptible TB, 454 individuals (19.4%) had a total of 534 individual PPTR events, of which 76.6% were microbiological (positive smear or culture at or after 17 wk). At least one PPTR event was experienced by 92.4% (133 of 144) of participants with TB-related unfavorable outcome and between 13.8% and 14.7% of participants with favorable and not-assessable outcomes. A total of 75% of participants with TB-related unfavorable outcomes had microbiological confirmation of failure to achieve a disease-free cure. Conclusions: Standardized methodologies, such as our PPTR approach, could facilitate unbiased efficacy outcome determinations, improve discrimination between outcomes that are related and unrelated to regimen efficacy, and enhance the ability to conduct pooled analyses of contemporary trials.

Circulating Cell-Free RNA in Blood as a Host Response Biomarker for the Detection of Tuberculosis

Tuberculosis (TB) remains a leading cause of death from an infectious disease worldwide. This is partly due to a lack of tools to effectively screen and triage individuals with potential TB. Whole blood RNA signatures have been extensively studied as potential biomarkers for TB, but they have failed to meet the World Health Organization's (WHOs) target product profiles (TPPs) for a non-sputum triage or diagnostic test. In this study, we investigated the utility of plasma cell-free RNA (cfRNA) as a host response biomarker for TB. We used RNA profiling by sequencing to analyze plasma samples from 182 individuals with a cough lasting at least two weeks, who were seen at outpatient clinics in Uganda, Vietnam, and the Philippines. Of these individuals, 100 were diagnosed with microbiologically-confirmed TB. Our analysis of the plasma cfRNA transcriptome revealed 541 differentially abundant genes, the top 150 of which were used to train 15 machine learning models. The highest performing model led to a 9-gene signature that had a diagnostic accuracy of 89.1% (95% CI: 83.6-93.4%) and an area under the curve of 0.934 (95% CI: 0.8674-1) for microbiologically-confirmed TB. This 9-gene signature exceeds the optimal WHO TPPs for a TB triage test (sensitivity: 96.2% [95% CI: 80.9-100%], specificity: 89.7% [95% CI: 72.4-100%]) and was robust to differences in sample collection, geographic location, and HIV status. Overall, our results demonstrate the utility of plasma cfRNA for the detection of TB and suggest the potential for a point-of-care, gene expression-based assay to aid in early detection of TB.

Introduction of the Simple One-Step stool Xpert Ultra method to detect TB in children and adults

SETTING: In 2020, the National TB Programme (NTP) of Vietnam conducted an implementation pilot of the Simple One-Step (SOS) stool processing method using Xpert^® MTB/RIF Ultra (Ultra) among children and people living with HIV (PLHIV) with signs and symptoms of TB.DESIGN and OBJECTIVES: Using data from this pilot and collecting information on healthcare workers´ (HCWs) perceptions, we assessed the feasibility, acceptability and potential impact of routine stool testing for TB.RESULTS: HCWs perceived collection of stools from children as least stressful of all sample types, stool processing as acceptable and the SOS stool method as easy to perform. After a 3-month induction period, the proportion of initial non-determinate Ultra stool tests was less than 5%. Combined Ultra testing of a respiratory sample and stool resulted in an increase in the proportion of bacteriologically confirmed TB among PLHIV and children by respectively 4.1% (95% CI 1.6-6.6) and 3.9% (95% CI 1.6-6.2). Among children, Mycobacterium tuberculosis was more often detected in stool (26.1%) than in respiratory samples (23.4%) (P = 0.06), including one child with rifampicin resistance.CONCLUSION: Stool testing can be feasibly implemented both in adult PLHIV and in children in routine settings, providing a non-invasive alternative sample type for the diagnosis of TB for patients who cannot produce sputum.

Does BCG vaccination protect against infection with M. tuberculosis?

BACKGROUND:

Protection against infection by the bacille Calmette-Guérin vaccine against Mycobacterium tuberculosis remains a subject of controversy. We investigated the association between BCG vaccination at birth and infection by M. tuberculosis.

MATERIAL AND METHODS:

This was a secondary analysis of data from tuberculin skin test (TST) surveys in Vietnamese schoolchildren between 1988 and 2001. We investigated whether a BCG scar was associated with a lower prevalence of TST positivity, adjusting for BCG-induced variation by varying cut-off values for a positive TST.

RESULTS:

We found a positive association between BCG scar and TST positivity. The strength of the association decreased with increasing TST cut-off values; however, it never inverted significantly, irrespective of geographic region and survey year.

CONCLUSION:

In Vietnam, BCG vaccination was not associated with reduced M. tuberculosis infection prevalence as measured using TST. This in contrary to a similar study conducted in Tanzania. These contradictory findings may be explained by geographical differences and the relatively high prevalence in Vietnam of the M. tuberculosis Beijing genotype, which is reported to be capable of circumventing BCG-induced immunity.

Overseas Treatment of Latent Tuberculosis Infection in US–Bound Immigrants

Seventy percent of tuberculosis (TB) cases in the United States occur among non–US-born persons; cases usually result from reactivation of latent TB infection (LTBI) likely acquired before the person’s US arrival. We conducted a prospective study among US immigrant visa applicants undergoing the required overseas medical examination in Vietnam. Consenting applicants >15 years of age were offered an interferon-γ release assay (IGRA); those 12–14 years of age received an IGRA as part of the required examination. Eligible participants were offered LTBI treatment with 12 doses of weekly isoniazid and rifapentine. Of 5,311 immigrant visa applicants recruited, 2,438 (46%) consented to participate; 2,276 had an IGRA processed, and 484 (21%) tested positive. Among 452 participants eligible for treatment, 304 (67%) initiated treatment, and 268 (88%) completed treatment. We demonstrated that using the overseas medical examination to provide voluntary LTBI testing and treatment should be considered to advance US TB elimination efforts.

Screening for Tuberculosis in Migrants: A Survey by the Global Tuberculosis Network

Tuberculosis (TB) does not respect borders, and migration confounds global TB control and elimination. Systematic screening of immigrants from TB high burden settings and-to a lesser degree TB infection (TBI)-is recommended in most countries with a low incidence of TB. The aim of the study was to evaluate the views of a diverse group of international health professionals on TB management among migrants. Participants expressed their level of agreement using a six-point Likert scale with different statements in an online survey available in English, French, Mandarin, Spanish, Portuguese and Russian. The survey consisted of eight sections, covering TB and TBI screening and treatment in migrants. A total of 1055 respondents from 80 countries and territories participated between November 2019 and April 2020. The largest professional groups were pulmonologists (16.8%), other clinicians (30.4%), and nurses (11.8%). Participants generally supported infection control and TB surveillance established practices (administrative interventions, personal protection, etc.), while they disagreed on how to diagnose and manage both TB and TBI, particularly on which TBI regimens to use and when patients should be hospitalised. The results of this first knowledge, attitude and practice study on TB screening and treatment in migrants will inform public health policy and educational resources.

Active surveillance for adverse events in patients on longer treatment regimens for multidrug-resistant tuberculosis in Viet Nam

OBJECTIVE

Management of multidrug-resistant tuberculosis (MDR-TB) is a significant challenge to the global healthcare system due to the complexity and long duration of the MDR-TB treatment. This study analyzed the safety of patients on longer injectable-based MDR-TB treatment regimens using active pharmacovigilance data.

METHOD

We conducted an observational, prospective study based on active pharmacovigilance within the national TB program. A total of 659 MDR-TB patients were enrolled and followed up at 9 TB- hospitals in 9 provinces of all 3 regions in Vietnam between 2014 and 2016. Patients received a treatment regimen (standardized or individualized) based on their drug susceptibility test result and their treatment history. Baseline and follow-up information was collected at the start and during treatment. Adverse events (AE) were defined and classified as serious adverse events (SAEs) or otherwise. Multivariate Cox regression following the Iterative Bayesian Model Averaging algorithm was performed to identify factors associated with AE occurrence.

RESULTS

Out of 659 patients assessed, 71.3% experienced at least one AE, and 17.5% suffered at least one SAE. The most common AEs were gastrointestinal disorders (38.5%), arthralgia (34.7%), and psychiatric disorders (30.0%). The proportion of patients with nephrotoxicity and hearing loss or vestibular disorders were 7.4% and 15.2%, respectively. 13.1% of patients required modifications or interruption of one or more drugs. In 77.7% of patients, treatment was completed successfully, while 9.3% lost to follow-up, in 3.0% treatment failed, and 7.4% died. Some significant risk factors for nephrotoxicity included diabetes mellitus (HR = 8.46 [1.91-37.42]), renal dysfunction (HR = 8.46 [1.91-37.42]), alcoholism (HR = 13.28 [5.04-34.99]), and a higher average daily dose of injectable drugs (HR = 1.28 [1.14-1.43]).

CONCLUSION

While a majority of patients on the longer injectable-based regimens experienced non-serious AEs during MDR-TB treatment, one in six patients experienced at least an SAE. Active TB drug-safety monitoring is useful to understand the safety of MDR-TB treatment and explore the risk factors for toxicity. All-oral, shorter MDR-TB regimens might be able to reduce the inconvenience, discomfort, and toxicity of such regimens and increase adherence and likelihood of successful completion.

Indoor Air Pollution and Susceptibility to Tuberculosis Infection in Urban Vietnamese Children

RATIONALE

The Southeast Asian tuberculosis burden is high, and it remains unclear if urban indoor air pollution in this setting is exacerbating the epidemic.

OBJECTIVES

To determine the associations of latent tuberculosis with common urban indoor air pollution sources (secondhand smoke, indoor motorcycle emissions, and cooking) in Southeast Asia.

METHODS

We enrolled child household contacts of patients with microbiologically confirmed active tuberculosis in Vietnam, July 2017-December 2019. We tested children for latent tuberculosis and evaluated air pollution exposures with questionnaires and personal aerosol sampling. We tested hypotheses using generalized estimating equations.

MEASUREMENTS AND MAIN RESULTS

We enrolled 72 tuberculosis patients (27% with cavitary disease) and 109 of their child household contacts. Of household contacts, 58 (53%) were diagnosed with latent tuberculosis at baseline visit. Children experienced a 2.56-fold increased odds of latent tuberculosis for each additional household member who smoked (95%CI 1.27-5.16). Odds were highest among children exposed to indoor smokers and children under five years old exposed to household smokers. Each residential floor above street-level pollution decreased the odds of latent tuberculosis by 36% (aOR 0.64, 95%CI 0.42-0.96). Motorcycles parked inside children's homes and cooking with liquid petroleum gas compared to electricity increased the odds of latent tuberculosis while kitchen ventilation decreased the effect, but these findings were not statistically significant.

CONCLUSION

Common urban indoor air pollution sources were associated with increased odds of latent tuberculosis infection in child household contacts of active tuberculosis patients.

Behaviors and Attitudes Toward Smoking Among Health Care Workers at Health Facilities in 4 Provinces of Vietnam: A Representative Cross-Sectional Survey

Tobacco smoking is a leading cause of premature death. Smoking prevalence in Vietnam ranks among the highest in Southeast Asia. Given the important role of health care workers (HCWs) in promoting and supporting smoking cessation, this project aimed to characterize the prevalence of smoking among HCWs in Vietnam, and their attitudes toward smoking cessation interventions. A cross-sectional survey was conducted among care workers in 4 levels of the health system, within 4 provinces of Vietnam. Descriptive statistics evaluated participant attitudes, perception, behaviors, and knowledge about smoking. Multivariable logistic regression models evaluated risk factors for smoking. Among 3343 HCWs, 7.5% identified as current smokers, comprising 22.2% males and 0.5% of females. Males had substantially greater odds (adjusted odds ratio = 55.3; 95% confidence interval = 29.0-105.6) of identifying as current smokers compared with females. HCWs in urban settings had higher odds of identifying as smokers compared with rural workers (adjusted odds ratio = 1.72; 95% confidence interval = 1.23-2.24). Strong support for smoking cessation policies and interventions were identified, even among staff who smoked. HCWs play an integral role in identifying smokers and supporting smoking cessation interventions for their patients. Efforts to support affordable smoking cessation interventions within health facilities are likely to contribute to a reduction in smoking prevalence in Vietnam.

Risk factors for TB among household contacts of patients with smear-positive TB in eight provinces of Vietnam: a nested case-control study

BACKGROUND

Tuberculosis (TB) continues to account for significant morbidity and mortality annually. Household contacts (HHCs) of persons with TB are a key population for targeting prevention and control interventions. We aimed to identify risk factors associated with developing TB among HHCs.

METHODS

We conducted a nested case-control study among HHCs in eight provinces in Vietnam who were enrolled in a randomized control trial of active case finding for TB. Cases were any HHCs diagnosed and registered with TB within the Vietnam National TB programme during two years of follow-up. Controls were selected by simple random sampling from the remaining HHCs. Risk factor data were collected at enrolment and during follow-up. A logistic regression model was developed to determine predictors of TB among HHCs.

RESULTS

We selected 1,254 HHCs for the analysis; 214 cases and 1,040 controls. Underlying characteristics varied between both groups; cases were older, more likely to be male, higher proportion of reported previous TB and diabetes. Risk factors associated with a TB diagnosis included being male (aOR 1.4; 95% CI: 1.03-2.0), residing in an urban setting (aOR 1.8; 1.3-2.5), prior TB (aOR 4.6; 95% CI: 2.5-8.7), history of diabetes (aOR 3.1; 95% CI: 1.7-5.8), current smoking (aOR 3.1; 95% CI: 2.2-4.4) and prolonged history of coughing in the source case at enrolment (OR 1.6; 95% CI: 1.1-2.3).

CONCLUSIONS

Household contacts remain and important key population for TB prevention and control. TB programmes should ensure effective contact investigations are implemented for household contacts, particularly those with additional risk factors for developing tuberculosis.

Household contact investigation for the detection of tuberculosis in Vietnam: economic evaluation of a cluster-randomised trial

BACKGROUND

Active case finding is recommended as an important strategy to control tuberculosis, particularly in low-income and middle-income countries with a high prevalence of the disease. However, the costs and cost-effectiveness of active case finding are unclear due to the absence of evidence from randomised trials. We assessed the costs and cost-effectiveness of an active case finding strategy in Vietnam, where there is a high prevalence of tuberculosis.

METHODS

We conducted an economic evaluation alongside the Active Case Finding in Tuberculosis (ACT2) trial-a pragmatic cluster-randomised controlled trial in 70 districts across eight provinces of Vietnam. Patients aged 15 years and older with smear-positive pulmonary tuberculosis were recruited to the trial if they lived with one or more other household members. Household contacts were verbally invited to the clinic by the index patient with tuberculosis. ACT2 compared a combination of active and passive case finding with usual care (passive case finding) of household contacts of patients with tuberculosis from a health system perspective. Clustering occurred at the district and household level. Districts were the unit of randomisation, and we used minimisation to ensure balance of intervention and control districts within each province. In the intervention group, participants were invited to attend screening at baseline, 6 months, 12 months, and 24 months. We determined health-care costs with a standardised national costing survey and reported results in 2017 $US. The primary outcome of our study was disability-adjusted life years (DALYs) averted over a 24-month period. ACT2 was registered prospectively with the Australian and New Zealand Clinical Trials Registry, number ACTRN126.100.00600044.

FINDINGS

Between Aug 11, 2010, and Aug 11, 2015, 10 964 index patients and 25 707 household contacts completed the ACT2 study. There were 10 069 household contacts in the intervention group and 15 638 household contacts in the control group. The incremental cost-effectiveness ratio per DALY averted was $544 (330-1375).

INTERPRETATION

Active case finding was shown to be highly cost-effective in a setting with a high prevalence of tuberculosis. Investment in the wide-scale implementation of this programme in Vietnam should be strongly supported.

FUNDING

Australian National Health and Medical Research Council.

Palliative care and symptom relief for people affected by multidrug-resistant tuberculosis

The World Health Organization (WHO) defines palliative care as the prevention and relief of the physical, psychological, social and spiritual suffering of adults and children with life-threatening illnesses and psycho-social support for their families. Palliative care and symptom relief (PCSR) also addresses suffering in nonlife-threatening situations such as after cure. PCSR should never be considered a substitute for tuberculosis (TB) prevention and treatment, but should be accessible by everyone in need. PCSR can reduce suffering and improve quality of life of patients with end-stage chronic illnesses while reducing costs for health care systems and providing financial risk protection for patients' families. It also may help enable patients to adhere to long and noxious treatments and thereby reduce mortality and help protect public health. Basic PCSR can be taught easily to TB specialists as well as primary care clinicians and delivered in hospitals, clinics or patients' homes combined with infection control. For these reasons, integration of PCSR into multidrug-resistant (MDR) and extensively drug-resistant TB (XDR-TB) treatment programs is medically and morally imperative. We propose an essential package of PCSR for people with M/XDR-TB that includes a set of safe, effective and inexpensive medicines and equipment, social supports for patients and caregivers living in extreme poverty, and necessary human resources. The package aligns with WHO guidance on programmatic management of drug-resistant (DR) TB and should be universally accessible by people affected by M/XDR-TB. We also describe the ethical practice of PCSR for people with M/XDR-TB and identify needed areas of research in PCSR for people with M/XDR-TB.

High-dose rifapentine with or without moxifloxacin for shortening treatment of pulmonary tuberculosis: Study protocol for TBTC study 31/ACTG A5349 phase 3 clinical trial

INTRODUCTION

Phase 2 clinical trials of tuberculosis treatment have shown that once-daily regimens in which rifampin is replaced by high dose rifapentine have potent antimicrobial activity that may be sufficient to shorten overall treatment duration. Herein we describe the design of an ongoing phase 3 clinical trial testing the hypothesis that once-daily regimens containing high dose rifapentine in combination with other anti-tuberculosis drugs administered for four months can achieve cure rates not worse than the conventional six-month treatment regimen.

METHODS/DESIGN

S31/A5349 is a multicenter randomized controlled phase 3 non-inferiority trial that compares two four-month regimens with the standard six-month regimen for treating drug-susceptible pulmonary tuberculosis in HIV-negative and HIV-positive patients. Both of the four-month regimens contain high-dose rifapentine instead of rifampin, with ethambutol replaced by moxifloxacin in one regimen. All drugs are administered seven days per week, and under direct observation at least five days per week. The primary outcome is tuberculosis disease-free survival at twelve months after study treatment assignment. A total of 2500 participants will be randomized; this gives 90% power to show non-inferiority with a 6.6% margin of non-inferiority.

DISCUSSION

This phase 3 trial formally tests the hypothesis that augmentation of rifamycin exposures can shorten tuberculosis treatment to four months. Trial design and standardized implementation optimize the likelihood of obtaining valid results. Results of this trial may have important implications for clinical management of tuberculosis at both individual and programmatic levels.

TRIAL REGISTRATION

NCT02410772. Registered 8 April 2015,https://www.clinicaltrials.gov/ct2/show/NCT02410772?term=02410772&rank=1.

Lung Volume Reduction Surgery in Patients with Heterogenous Emphysema: Selecting Perspective

BACKGROUND:

Lung volume reduction surgery (LVRS) was introduced to alleviate clinical conditions in selected patients with heterogenous emphysema. Clarifying the most suitable patients for LVRS remained unclear.

AIM:

This study was undertaken to specifically analyze the preoperative factor affecting to LVRS.

METHODS:

The prospective study was conducted at 103 Military Hospital between July 2014 and April 2016. Severe heterogenous emphysema patients were selected to participate in the study. The information, spirometry, and body plethysmographic pulmonary function tests in 31 patients who underwent LVRS were compared with postoperative outcomes (changing in FEV1 and CAT scale).

RESULTS:

Of the 31 patients, there was statistically significant difference in the outcome of functional capacity, lung function between two groups (FEV1 ≤ 50% and > 50%) (∆FEV1: 22.46 vs 18.32%; p = 0.042. ∆ CAT: 6.85 vs 5.07; p = 0.048). Changes of the FEV1 and CAT scale were no statistically significant differences in three groups residual volume. Patients with total lung capacity < 140% had more improved than others (∆FEV1: 23.81 vs 15.1%; p = 0.031).

CONCLUSION:

Preoperative spirometry and body plethysmographic pulmonary function tests were useful measures to selected severe heterogenous emphysema patients for LVRS. Patients with FEV1 ≤ 50%, TLC in the range of 100-140% should be selected.

National tuberculosis patients cost survey: research findings lead to change in policy and practice, Viet Nam

In 2016, the Viet Nam National Tuberculosis Programme (NTP) conducted the first national TB patients cost survey to identify the main cost drivers to help guide cost mitigation policies and reduce financial barriers to the treatment of TB patients. The survey findings were widely disseminated and the NTP defined a roadmap. The major components of the roadmap included 1) advocating for patients to be covered by social health insurance; 2) creating a charity fund for TB patients; 3) strengthening the collaboration between the Ministry of Health and Ministry of Labour and Social Affairs; and 4) advocating for donor support. The first national TB patients cost survey has shown that a high proportion of TB patients incurred costs that were classed as 'catastrophic'. The survey findings led to policy changes and new practices in Viet Nam.

Effect of two alternative methods of pooling sputum prior to testing for tuberculosis with genexpert MTB/RIF

Background

Pooling sputum specimens is one potential strategy for reducing the cost of using Xpert MTB/RIF, a rapid polymerase chain reaction (PCR)-based test, for the diagnosis of pulmonary tuberculosis. We sought to compare the sensitivity of two alternative method of pooling.

Methods

Patients referred for assessment for TB, whose initial sputum was Xpert MTB positive, were recruited and their sputum specimens were pooled for analysis with sputum specimens that were Xpert MTB negative. Two alternative pooling strategies were employed: one in which the concentration of sample reagent (buffer) was maintained at 2:1 (standard), in accordance with the manufacturer’s instructions, and another in which the concentration of sample reagent was reduced to 1:1.

Results

We tested 101 Xpert MTB positive sputum specimens. Among these, 96% of valid test results (95% confidence interval (CI) 89–99%) were positive using the “standard buffer method”. Using the “reduced buffer pooling” method 94% of valid test results (95% CI 87–98%) were positive. McNemar’s test for the difference in paired proportions did not reach statistical significance (P = 0.56).

Conclusion

We have confirmed that pooling of two sputum specimens for testing in a single cartridge is a valid method of reducing the number of cartridges required when using Xpert MTB to detect pulmonary tuberculosis. Two alternative pooling strategies tested here yielded similar results.

Trial registration

The present study was conducted within the Active Casefinding in Tuberculosis (ACT3) Trial. The ACT3 Trial had been registered with Australian and New Zealand Clinical Trials Register on 8th April, 2014. The trial registration number is ACTRN12614000372684. (Retrospectively registered).

Progress towards universal HIV testing among TB patients in Viet Nam: a retrospective cohort evaluation of TB/HIV surveillance, 2011-2017

BACKGROUND

Tuberculosis (TB) and HIV remain a major causes of morbidity and mortality globally. We conducted an analysis of TB/HIV surveillance data to describe the trends in HIV testing coverage and HIV positivity rate among TB patients in Viet Nam, 2011-2017.

MAIN TEXT

This was a descriptive study based on review and analysis of surveillance data from the National Tuberculosis Control Programme from 2011 to 2017. During this period, 721 342 TB cases were diagnosed. Of these, 520 490 (72.2%) had a previously documented HIV status or were tested for HIV during TB care and treatment. The proportion of TB patients whose HIV status was reported increased, from 58.5% in 2011 to 82.9% in 2017 (P value for trend = 0.014). The proportion of TB patients infected with HIV decreased, from 8.0% in 2011 to 3.7% in 2017 (P value for trend = 0.018).

CONCLUSIONS

The proportion of TB patients with a reported HIV status was increased from 2011 to 2017, however HIV testing coverage remained below the National Tuberculosis Control Programme targets (≥ 90%). National Tuberculosis Control Programme needs to focus on ensuring every registered TB patients has a documented HIV status, ensuring full coverage of HIV testing as part of routine TB care.

Prevalence and associated factors of diabetes mellitus among tuberculosis patients in Hanoi, Vietnam

BACKGROUND

Diabetes mellitus (DM) is recognized as an important comorbidity for the development of tuberculosis (TB). With the increase of DM burden globally, concerns have been raised about the emerging co-epidemics of DM and TB, especially in low- and middle-income countries.

METHODS

A facility-based, cross-sectional study was carried out in all 30 district TB units in Hanoi, Vietnam. All eligible, diagnosed TB patients aged 15 years old or older were asked to provide consent and were screened for diabetes using fasting blood glucose (FBG). Pre-tested semi-structured questionnaires were used for collecting demographic data, lifestyle habits and clinical data. Identification of pre-diabetes or diabetes in TB patients was done in accordance to parameters set by the American Diabetes Association (2016).

RESULTS

Of 870 eligible TB patients, 831 (95.5%) participated in the study. Of those, 241 (29%; 95%CI: 25.9-32.1%) were prediabetic and 114 (13.7%; 95%CI: 11.4-16.1%) were found to have DM. The risk of DM was higher in patients belonging to the age group 40-64 years (OR 6.09; 95%CI 2.81-13.2); or the age group 65 years or older (OR 2.65; 95%CI 1.65-4.25) or who have a family history of DM (OR 2.71; 95%CI 1.33-5.50).

CONCLUSIONS

This study demonstrated high prevalence of DM and prediabetes among TB patients in Hanoi, Vietnam. National Tuberculosis Programme needs to establish a systematic screening process for DM among TB patients.

Costs of providing tuberculosis diagnosis and treatment services in Viet Nam

OBJECTIVE

To estimate the cost of providing tuberculosis (TB) diagnosis and treatment packages at different levels of health facilities in Viet Nam.

DESIGN

This was a retrospective costing study from the providers' perspective using a standard costing approach. We included typical services for TB diagnosis and treatment based on standard protocols.

RESULTS

The least expensive TB service was the 6-month isoniazid preventive therapy regimen for latent tuberculous infection provided by district health centres (US$7.20-14.30, accounting for 0.3-0.7% of Viet Nam's per capita gross domestic product [GDP] of US$2052.30 in 2014). The cost of diagnosing and treating a patient with drug-susceptible TB (the most common type of TB) ranged between US$51.20 and US$180.70, and represented 2.5-8.8% of Viet Nam's per capita GDP in 2014. The most expensive TB service was the diagnosis and treatment of a multidrug-resistant TB case (US$1568.20-2391.20), accounting for 76.4-116.5% of Viet Nam's per capita GDP in 2014).

CONCLUSION

The cost of TB diagnosis and treatment services in Viet Nam varied according to level of health facility, type of TB, different costing options, and different staff cost scenarios.

Comparison of HIV Testing among Children and Adults with Tuberculosis, Vietnam

HIV testing among persons with tuberculosis (TB) results in high-yield identification of persons infected with HIV. To evaluate differences in HIV testing among children versus adults with TB in Vietnam, we collected and analyzed age-disaggregated facility and aggregated provincial data from the National Tuberculosis Program. HIV testing was incompletely documented for >70% of children, whereas adult testing data were >90% complete. Standardized training of personnel for universal HIV testing and documentation for children with TB could improve HIV case-detection and permit linking of children with HIV to antiretroviral treatment to prevent morbidity and mortality.

The role of macroscopic sputum quality assessments to optimise sputum testing for tuberculosis

SETTING

Community-wide active case finding for tuberculosis (TB) using Xpert® MTB/RIF as the primary screening tool, Ca Mau Province, Viet Nam.

OBJECTIVES

To determine whether macroscopic sputum quality characteristics (sputum colour and volume) can be used to predict Xpert MTB-negative sputum and hence exclude sputum samples from testing.

DESIGN

Field staff conducted household visits to approximately 51,200 adults in 58 villages randomly selected from throughout the province. Sputum samples from all screened participants who were able to produce ⩾1 ml sputum underwent macroscopic sputum assessment and were tested with Xpert.

RESULTS

Of the 21,624 sputum samples tested, 159 (0.74%) were Xpert MTB-positive; 93% of the samples were 1-2 ml and nearly all were mucoid (93%) or mucopurulent (5.7%). One salivary sample was Xpert MTB-positive (2.0% of all salivary samples). The lowest positive predictive value for any sputum volume or colour characteristic was 0.66%. This was not substantially different from the overall prevalence of positive sputum Xpert MTB (0.74%).

CONCLUSION

Sputum colour and volume cannot be used to predict the presence or absence of M. tuberculosis in sputum detected using Xpert. These sputum quality parameters cannot therefore be used to exclude sputum samples from testing for TB.

The effects of placing an operational research fellow within the Viet Nam National Tuberculosis Programme

In April 2009, an operational research fellow was placed within the Viet Nam National Tuberculosis Control Programme (NTP). Over the 6 years from 2010 to 2015, the OR fellow co-authored 21 tuberculosis research papers (as principal author in 15 [71%]). This constituted 23% of the 91 tuberculosis papers published in Viet Nam during this period. Of the 21 published papers, 16 (76%) contributed to changes in policy (n = 8) and practice (n = 8), and these in turn improved programme performance. Many papers also contributed important evidence for better programme planning. Highly motivated OR fellows embedded within NTPs can facilitate high-quality research and research uptake.

Infection control and tuberculosis among health care workers in Viet Nam, 2009-2013: a cross-sectional survey

Background

Data on tuberculosis (TB) among health care workers (HCW) and TB infection control (TBIC) indicators are rarely available at national level. We assessed multi-year trends in notification data of TB among HCW and explored possible associations with TBIC indicators.

Methods

Notified TB incidence among HCW and 3 other TBIC indicators were collected annually from all 64 provincial and 3 national TB facilities in Vietnam. Time trends in TB notification between 2009 and 2013 were assessed using linear regression analysis. Multivariate regression models were applied to assess associations between the facility-specific 5-year notification rate and TBIC indicators.

Results

Forty-seven (70 %) of 67 facilities contributed data annually over five years; 15 reported at least one HCW with TB in 2009 compared to six in 2013. The TB notification rate dropped from 593 to 197 per 100,000 HCW (p_trend = 0.02).

Among 104 TB cases reported, 30 were employed at TB wards, 24 at other clinical wards, ten in the microbiology laboratory, six at the MDR-TB ward, and 34 in other positions.

The proportion of facilities with a TBIC plan and focal person remained relatively stable between 70 % and 84 %. The proportion of facilities providing personal protective equipment (PPE) to their staff increased over time. Facilities with a TBIC focal person were 7.6 times more likely to report any TB cases than facilities without a focal person.

Conclusions

The TB notification rates among HCW seemed to decrease over time. Availability of PPE increased over the same period. Appointing a TBIC focal person was associated with reporting of TB cases among HCW. It remains unclear whether TBIC measures helped in reduction of the TB notification rates in HCW.

Evaluation of mobile digital light-emitting diode fluorescence microscopy in Hanoi, Viet Nam

SETTING

Hanoi Lung Hospital, Hanoi, Viet Nam.

OBJECTIVE

To compare the accuracy of CellScopeTB, a manually operated mobile digital fluorescence microscope, with conventional microscopy techniques.

DESIGN

Patients referred for sputum smear microscopy to the Hanoi Lung Hospital from May to September 2013 were included. Ziehl-Neelsen (ZN) smear microscopy, conventional light-emitting diode (LED) fluorescence microscopy (FM), CellScopeTB-based LED FM and Xpert(®) MTB/RIF were performed on sputum samples. The sensitivity and specificity of microscopy techniques were determined in reference to Xpert results, and differences were compared using McNemar's paired test of proportions.

RESULTS

Of 326 patients enrolled, 93 (28.5%) were Xpert-positive for TB. The sensitivity of ZN microscopy, conventional LED FM, and CellScopeTB-based LED FM was respectively 37.6% (95%CI 27.8-48.3), 41.9% (95%CI 31.8-52.6), and 35.5% (95%CI 25.8-46.1). The sensitivity of CellScopeTB was similar to that of conventional LED FM (difference -6.5%, 95%CI -18.2 to 5.3, P = 0.33) and ZN microscopy (difference -2.2%, 95%CI -9.2 to 4.9, P = 0.73). The specificity was >99% for all three techniques.

DISCUSSION

CellScopeTB performed similarly to conventional microscopy techniques in the hands of experienced TB microscopists. However, the sensitivity of all sputum microscopy techniques was low. Options enabled by digital microscopy, such as automated imaging with real-time computerized analysis, should be explored to increase sensitivity.

Collaborative activities and treatment outcomes in patients with HIV-associated tuberculosis in Viet Nam

SETTING

The National Tuberculosis (TB) Programme in Viet Nam and Ho Chi Minh City (HCMC).

OBJECTIVES

To determine 1) at national level between 2011 and 2013, the relationship between human immunodeficiency virus (HIV) testing, uptake of TB-HIV interventions and adverse treatment outcomes among TB-HIV patients; and 2) in HCMC in 2013, patient characteristics associated with adverse outcomes.

DESIGN

An ecological study reviewing aggregate nationwide data and a retrospective cohort review in HCMC.

RESULTS

Nationwide, from 2011 to 2013, HIV testing increased in TB patients from 58% to 68% and antiretroviral therapy (ART) increased in TB-HIV patients from 54% to 63%. Adverse treatment outcomes in TB-HIV patients increased from 24% to 27%, largely due to transfer out (5-9% increase) and death. The Northern and Highland regions showed poor uptake of TB-HIV interventions. In HCMC, 303 (27%) of 1110 TB-HIV patients had adverse outcomes, with higher risks observed in those with previously treated TB, those diagnosed as HIV-positive before TB onset and those never placed on cotrimoxazole or ART.

CONCLUSION

Despite improving HIV testing rates and TB-HIV interventions, adverse outcomes in TB-HIV patients remain at about 26%. Characteristics predicting higher risk of adverse outcomes must be addressed if Viet Nam wishes to end the TB epidemic by 2030.

Management and treatment outcomes of patients enrolled in MDR-TB treatment in Viet Nam

SETTING

The programmatic management of drug-resistant tuberculosis (TB) in Viet Nam has been rapidly scaled up since 2009.

OBJECTIVES

To document the annual numbers of patients enrolled for multidrug-resistant tuberculosis (MDR-TB) treatment during 2010-2014 and to determine characteristics and treatment outcomes of patients initiating treatment during 2010-2012.

DESIGN

A retrospective cohort study using national reports and data from the national electronic data system for drug-resistant TB.

RESULTS

The number of patients enrolled annually for MDR-TB treatment increased from 97 in 2010 to 1522 in 2014. The majority of patients were middle-aged men who had pulmonary disease and had failed a retreatment regimen; 77% had received ⩾2 courses of TB treatment. Favourable outcomes (cured and treatment completed) were attained in 73% of patients. Unfavourable outcomes included loss to follow-up (12.5%), death (8%) and failure (6.3%). Having had ⩾2 previous treatment courses and being human immunodeficiency virus-positive were associated with unfavourable outcomes.

CONCLUSION

Increasing numbers of patients are being treated for MDR-TB each year with good treatment outcomes under national programme management in Viet Nam. However, there is a need to increase case detection-currently at 30% of the estimated 5100 MDR-TB cases per year, reduce adverse outcomes and improve monitoring and evaluation.

Western Pacific Regional Green Light Committee: progress and way forward

•

The Western Pacific Regional Green Light Committee (rGLC WPR) was established in 2011 to promote scale-up of programmatic management of drug-resistant tuberculosis (PMDT).

•

rGLC WPR has generated greater awareness of regional challenges and has encouraged local solutions to regional problems.

•

PMDT should be part and parcel of routine TB programme activity.

•

Challenges and bottlenecks have varied according to the different stages of PMDT implementation, requiring different types of technical assistance.

•

Regional initiatives should be dynamic and responsive to the needs of countries.

The Western Pacific Regional Green Light Committee (rGLC WPR) was established in 2011 to promote the rational scale-up of programmatic management of drug-resistant tuberculosis (PMDT). We reflect on its achievements, consider the challenges faced, and explore its potential future role. Achievements include the supervision and support of national PMDT action plans, increased local ownership, contextualized guidance, and a strong focus on regional capacity building, as well as a greater awareness of regional challenges. Future rGLC activities should include (1) advocacy for high-level political commitment; (2) monitoring, evaluation, and supervision; (3) technical support and contextualized guidance; and (4) training, capacity building, and operational research. Regional activities require close collaboration with both national and global efforts, and should be an important component of the new Global Drug-resistant TB Initiative.

The fourth national anti-tuberculosis drug resistance survey in Viet Nam

SETTING

Viet Nam's Fourth National Anti-Tuberculosis Drug Resistance Survey was conducted in 2011.

OBJECTIVE

To determine the prevalence of resistance to the four main first-line anti-tuberculosis drugs in Viet Nam.

METHODS

Eighty clusters were selected using a probability proportion to size approach. Drug susceptibility testing (DST) against the four main first-line anti-tuberculosis drugs was performed.

RESULTS

A total of 1629 smear-positive tuberculosis (TB) patients were eligible for culture. Of these, DST results were available for 1312 patients, including 1105 new TB cases, 195 previously treated TB cases and 12 cases with an unknown treatment history. The proportion of cases with resistance to any drug was 32.7% (95%CI 29.1-36.5) among new cases and 54.2% (95%CI 44.3-63.7) among previously treated cases. The proportion of multidrug-resistant TB (MDR-TB) cases was 4.0% (95%CI 2.5-5.4) in new cases and 23.3 (95%CI 16.7-29.9) in previously treated cases.

CONCLUSIONS

The fourth drug resistance survey in Viet Nam found that the proportion of MDR-TB among new and previously treated cases was not significantly different from that in the 2005 survey. The National TB Programme should prioritise the detection and treatment of MDR-TB to reduce transmission of MDR-TB in the community.

Adverse events in the treatment of MDR-TB patients within and outside the NTP in Pham Ngoc Thach hospital, Ho Chi Minh City, Vietnam

Background

Treatment outcomes of a high proportion of inpatients with multi-drug resistant tuberculosis (MDR-TB) were not reported to the Vietnamese National Tuberculosis Program because they received treatment outside of the green light committee (GLC) program. The study aimed (1) to describe the strengths and weaknesses of treatment of GLC and non-GLC MDR-TB patients as well as the factors influencing treatment completion and (2) to determine the incidence of adverse drug reactions.

Results

This cross-sectional study comprised two elements: (1) in-depth interviews with clinical doctors, hospital pharmacists; and focus group discussions with MDR-TB patients; and (2) a review of the charts of all GLC and non-GLC MDR-TB patients in 2010. A total of 282 MDR-TB patients were recruited, including 79(28 %) MDR-TB patients treated through the GLC program and 203(72 %) MDR-TB patients treated outside of the GLC program. The main strengths of GLC treatment were the supply of quality assured second line TB drugs, routine monitoring and clinical evaluation, free diagnostic tests and close clinical monitoring. The greatest barriers to patients treated outside of the GLC program was difficulty paying for second line TB drugs and other treatment costs. There was no significant difference between the incidence of adverse events among GLC (46.8 %) and non-GLC treated patients (52.2 %; p = 0.417). Among 143 patients who reported 226 adverse reaction events, arthralgia/joint pain (35.8 %), gastrointestinal (14.2 %), ototoxicity (8.4 %), cutaneous (6.6 %), and giddiness (5.8 %) were the most common.

Conclusions

The non-GLC MDR-TB patients face substantial barriers to treatment, and require greater support if they are to complete treatment and improve disease outcomes. Staff training about the management of adverse drug reactions is needed.

Barriers to adherence with tuberculosis contact investigation in six provinces of Vietnam: a nested case-control study

Background

Close contacts of patients with tuberculosis (TB) have a substantial risk of developing the disease, particularly during the first year after exposure. Household contact investigation has recently been recommended as a strategy to enhance case detection in high-burden countries. However the barriers to its implementation in these settings remain poorly understood.

Methods

A nested case–control study was conducted in Vietnam within the context of a large cluster randomised controlled trial of active screening for TB in household contacts of patients with pulmonary TB. The study population comprised contacts (and their index patients) from 12 Districts in six provinces throughout the country. Cases were contacts (and their index patients) that did not attend the scheduled screening appointment. Controls were those who did attend. We assessed relevant knowledge, attitudes and practices in cases and controls.

Results

The acceptability of contact investigation was high among both cases (n = 109) and controls (n = 194). Both cases (47%) and controls (36%) commonly reported discrimination against people with TB. Cases were less likely than controls to understand that sharing sleeping quarters with a TB patient increased their risk of disease (OR 0.46, 0.27 – 0.78) or recognise TB as an infectious disease (OR 0.65, 0.39 – 1.08). A higher proportion of cases than controls held the mistaken traditional belief that a non-infectious form of TB caused the disease (OR 1.69, 1.02 – 2.78).

Conclusions

The knowledge, attitudes and practices of contacts and TB patients influence their ongoing participation in contact investigation. TB case detection policies in high-prevalence settings can be strengthened by systematically evaluating and addressing locally important barriers to attendance.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12610000600044.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-0816-0) contains supplementary material, which is available to authorized users.

Tuberculosis case notification data in Viet Nam, 2007 to 2012

Tuberculosis (TB) remains a major cause of morbidity and mortality, and Viet Nam ranks 12 among the 22 high-TB burden countries. This study analyses surveillance data of the National Tuberculosis Control Programme in Viet Nam for the six-year period 2007 to 2012. During the study period, 598,877 TB cases (all forms) were notified, and 313,225 (52.3%) were new smear-positive cases. The case notification rate of new smear-positive cases was decreased, from 65 per 100,000 population in 2007 to 57 per 100,000 population in 2012; this decrease was observed for males and females in all age groups except males aged 0-14 and females aged 15-24 years. The male-to-female ratio of new smear-positive TB cases increased from 2.85 in 2007 to 3.02 in 2012. The average annual cure rate of new smear-positive cases was 90.3%. The high male-to-female ratio for new smear-positive TB cases in this notification data was lower than that from the 2007 TB prevalence survey in Viet Nam, suggesting a lower case detection for males. The decrease in new smear-positive case notification rates may reflect a decline in TB incidence in Viet Nam as several programmatic improvements have been made, although further research is required to increase case detection among young males and children.

Household contact investigation for tuberculosis in Vietnam: study protocol for a cluster randomized controlled trial

Background

Tuberculosis is an infectious disease that continues to cause considerable morbidity and mortality globally. Only 65% of patients worldwide are currently diagnosed. Contact investigation is a strategy that aims to increase case detection and reduce transmission of tuberculosis, yet there is little evidence to show its effectiveness.

Methods/Design

We will conduct a cluster randomized controlled trial of contact investigation within the national tuberculosis control program of Vietnam. Household contacts of patients with smear-positive pulmonary tuberculosis will be invited to attend district tuberculosis units for symptom screening, examination, and chest radiography on four occasions over a two-year period. The primary endpoint is clinically confirmed tuberculosis among contacts during the 24 months of follow-up, ascertained using capture-recapture analysis. Microbiologically proven tuberculosis and treatment completion rates among contacts diagnosed with tuberculosis will be secondary endpoints. The incremental cost-effectiveness ratio will be estimated. The study will have 80% power to detect a 50% increase in the primary endpoint in the active intervention arm compared with the control arm. The study will include 8,829 contacts in each of the active screening and control groups, within 70 districts in 8 provinces in Vietnam, in both rural and urban settings.

Discussion

The effectiveness of contact investigation as a tool for improved tuberculosis case finding has not been established. This cluster randomized trial will provide valuable operational information for national tuberculosis programs in high-prevalence countries, in order to select the most cost-effective strategies to improve tuberculosis case detection.

Trial registration

The ACT2 study has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000600044).

Free tuberculosis diagnosis and treatment are not enough: patient cost evidence from three continents

SETTING

The National Tuberculosis Programs of Ghana, Viet Nam and the Dominican Republic.

OBJECTIVE

To assess the direct and indirect costs of tuberculosis (TB) diagnosis and treatment for patients and households.

DESIGN

Each country translated and adapted a structured questionnaire, the Tool to Estimate Patients' Costs. A random sample of new adult patients treated for at least 1 month was interviewed in all three countries.

RESULTS

Across the countries, 27-70% of patients stopped working and experienced reduced income, 5-37% sold property and 17-47% borrowed money due to TB. Hospitalisation costs (US$42-118) and additional food items formed the largest part of direct costs during treatment. Average total patient costs (US$538-1268) were equivalent to approximately 1 year of individual income.

CONCLUSION

We observed similar patterns and challenges of TB-related costs for patients across the three countries. We advocate for global, united action for TB patients to be included under social protection schemes and for national TB programmes to improve equitable access to care.

Contact investigation in households of patients with tuberculosis in Hanoi, Vietnam: a prospective cohort study

Setting

Existing tuberculosis control strategies in Vietnam are based on symptomatic patients attending health services for investigation. This approach has not resulted in substantial reductions in the prevalence of tuberculosis disease, despite the National Tuberculosis Program achieving high treatment completion rates. Alternative approaches are being considered.

Objective

To determine the feasibility and yield of contact investigation in households of patients with smear positive pulmonary tuberculosis among household members of tuberculosis patients in Hanoi, Vietnam.

Methods

Household contacts of patients with smear positive pulmonary tuberculosis were recruited at four urban and rural District Tuberculosis Units in Hanoi. Clinical and radiological screening was conducted at baseline, six months and 12 months. Sputum microscopy and culture was performed in contacts suspected of having tuberculosis. MIRU-VNTR molecular testing was used to compare the strains of patients and their contacts with disease.

Results

Among 545 household contacts of 212 patients, four were diagnosed with tuberculosis at baseline (prevalence 734 cases per 100,000 persons, 95% CI 17–1451) and one was diagnosed with tuberculosis during the subsequent 12 months after initial screening (incidence 180 cases per 100,000 person-years, 95% CI 44–131). Two of these cases were culture positive for M. tuberculosis and both had identical or near-identical MIRU-VNTR strain types.

Conclusion

Household contacts of patients with potentially infectious forms of tuberculosis have a high prevalence of disease. Household contact investigation is feasible in Vietnam. Further research is required to investigate its effectiveness.

Yield of interview screening and chest X-ray abnormalities in a tuberculosis prevalence survey

BACKGROUND

Tuberculosis (TB) prevalence surveys generally rely on a combination of screening methods to identify suspects eligible for sputum culture.

OBJECTIVE

To assess the yield of screening methods applied in a recent prevalence survey in Viet Nam and estimate the proportion of TB cases missed due to incomplete participation.

METHODS

TB suspects were identified based on self-reported TB history or productive cough by interview and chest X-ray (CXR). We calculated the case yield of these two screening methods by dividing the number of cases detected per method by the total number of cases detected. As not all participants underwent the full screening procedure, we recalculated the maximum yield of the screening methods using multiple imputation methods.

RESULTS

The yield from screening by interview and CXR were respectively 38% and 91%. Adjusting for missing data by multiple imputation, we estimated that we missed 9.9% (95%CI 6.8-14.2) of expected TB cases.

CONCLUSION

In prevalence surveys, screening by pre-structured interview is insufficient, and should be supplemented with CXR to achieve sufficient identification of TB cases. The effect of incomplete participation in the full screening procedure may be substantial and should be adjusted for in the analysis.

Health-seeking behaviour among adults with prolonged cough in Vietnam

OBJECTIVE

To assess health-seeking behaviour among adults with prolonged cough in a population-based, nationally representative sample in Vietnam.

METHODS

Cross-sectional survey conducted from September 2006 to July 2007. All inhabitants aged ≥15 years were invited for screening for cough, history of tuberculosis (TB) treatment and chest X-ray (CXR) examination. TB suspects, defined as any survey participant with CXR abnormalities consistent with TB, or productive cough for more than 2 weeks or TB treatment either currently or in the preceding 2 years submitted sputum specimens for smear examination and culture and provided information on health-seeking behaviour in an in-depth interview.

RESULTS

Of 94 179 persons participating in the survey, 4.6% had prolonged productive cough. Forty-four percentage of those had sought health care and reported pharmacies (35%), commune health posts (29%), public hospitals (24%) and private physicians (10%) as first point of contact. Only 7% had undergone sputum smear examination. Of TB suspects with prolonged productive cough, 2.9% were diagnosed with TB; 10.2% of these reported smear and 21.9% reported X-ray examination when visiting a health care facility. The average patient delay was 4.1 weeks (95% CI: 3.9-4.4) among cough suspects and 4.0 weeks (95% CI: 3.1-4.9) among TB cases.

CONCLUSIONS

In this Vietnamese survey, nearly half of persons with cough for more than 2 weeks had visited a health care provider. The commonest first health facility contacted was the pharmacy. Sputum smears were rarely examined, except in the provincial TB hospital. Our findings highlight the need to improve diagnostic practices by retraining health staff on the performance of sputum examination for TB suspects.

Measurement of exhaled nitric oxide as a potential screening tool for pulmonary tuberculosis

BACKGROUND

There is a need for low-technology, inexpensive screening tools for active tuberculosis (TB) case finding.

OBJECTIVE

to assess the potential usefulness of measuring exhaled nitric oxide (eNO).

DESIGN

Cross-sectional comparison in Hanoi, Viet Nam, comparing 90 consecutive smear-positive, culture-confirmed TB patients presenting at a referral hospital with office workers (no X-ray confirming TB) at this hospital (n = 52) and at a construction firm (n = 84). eNO levels were analysed using a validated handheld analyser.

RESULTS

eNO levels among TB patients (median 15 parts per billion [ppb], interquartile range [IQR] 10-20) were equal to those among construction firm workers (15 ppb, IQR 12-19, P = 0.517) but higher than those among hospital workers (8.5 ppb, IQR 5-12.5, P < 0.001). Taking the hospital workers as the comparison group, best performance as a diagnostic tool was at a cut-off of 10 ppb, with sensitivity 78% (95%CI 68-86) and specificity 62% (95%CI 47-75). Test characteristics could be optimised to 84% vs. 67% by excluding individuals who had recently smoked or consumed alcohol.

CONCLUSION

While eNO measurement has limited value in the direct diagnosis of pulmonary TB, it may be worth developing and evaluating as a cost-effective replacement of chest X-ray in screening algorithms of pulmonary TB where X-ray is not available.

Household expenditure and tuberculosis prevalence in VietNam: prediction by a set of household indicators

OBJECTIVE

To study the association between TB and household expenditure in a nationwide TB prevalence survey in Viet Nam using nine household characteristics.

METHOD

To assess the prevalence of TB in Viet Nam, a nationwide stratified cluster sample survey was conducted from 2006 to 2007. Nine household characteristics used in the second Viet Nam Living Standards Survey (VLSS) were scored per household. In the VLSS dataset, we regressed these nine characteristics against household expenditure per capita, and used the coefficients to predict household expenditure level (in quintiles) in our survey and assess its relation with TB prevalence.

RESULTS

The prevalence of bacteriologically confirmed TB was 307 per 100,000 population in persons aged ≥ 15 years (95%CI 249-366). After adjustment for confounders, prevalence was found to be associated with household expenditure level: the rate was 2.5 times higher for those in the lowest household expenditure quintile (95%CI 1.6-3.9) than those in the highest quintile.

CONCLUSION

With a set of nine household characteristics, we were able to predict household expenditure level fairly accurately. There was a significant association between TB prevalence rates and estimated household expenditure level, showing that TB is related to poverty in Viet Nam.

National survey of tuberculosis prevalence in Viet Nam

OBJECTIVE

To estimate the prevalence of tuberculosis in Viet Nam with data from a population-based survey, compare it with the prevalence estimated by the World Health Organization, and identify major demographic determinants of tuberculosis prevalence.

METHODS

A cross-sectional survey with multistage cluster sampling, stratified by urban, rural and remote areas, was done in 2006-2007 in 70 communes. All inhabitants aged > or = 15 years were invited for cough and chest X-ray examination. Participants with findings suggestive of tuberculosis provided sputum specimens for smear examination and culture. Point prevalence estimates, 95% confidence intervals and design effects were calculated. Confidence intervals and P-values were adjusted for the cluster design.

FINDINGS

Of 114,389 adult inhabitants, 94 179 (82.3%) were screened. Of 87,314 (92.7%) screened by both questionnaire and chest X-ray, 3522 (4.0%) had productive cough, 518 (0.6%) had a recent history of tuberculosis and 2972 (3.4%) had chest X-ray abnormalities suggestive of tuberculosis. Sputum tests were done for 7648 participants. Sputum test, bacterial culture or both confirmed 269 tuberculosis cases, 174 of which were smear-positive. The prevalence rate of smear-positive tuberculosis was 145 per 100,000 (95% confidence interval: 110-180) assuming no tuberculosis in persons aged < 15 years. Prevalence was 5.1 times as high in men as in women, increased with age, was higher in rural than in urban or remote areas and showed a north-to-south gradient.

CONCLUSION

In Viet Nam, the tuberculosis prevalence rate based on positive sputum smear tests was 1.6 times as high as previously estimated. Age and sex patterns were consistent with notification data. Tuberculosis control should remain a high priority in Viet Nam.

[Expression of p53, p21 and bcl-2 in prognosis of lung carcinomas]

Expression of suppressor genes 53 and bcl-2 as well as of protein p21 (partly induced by p53 gene) was analyzed in a group of 77 resection specimens and bronchial excision of lung carcinomas (of all basic histological types--squamous cell, neuroendocrine, adenocarcinoma, undifferentiated). Simultaneously the relation of tumor immunophenotype and level of differentiation, cell death and 2-year-survival of patients was evaluated. Gene p53 showed non-only an expected strong expression in squamous cell carcinomas but especially in adenocarcinomas, which were newly characterized by exceptional hyper-expression of p53 in lowly differentiated variants. Expression level of protein p21 and gene p53 was parallel only in adenocarcinomas and undifferentiated carcinomas but discordant in squamous cell and neuroendocrine carcinomas. Positivity of p21 slightly prevailed in well-differentiated variants of the histological types but an exceptional positivity was found even in all the undifferentiated carcinomas. Gene bcl-2 revealed a paradox of strong expression in lowly differentiated neuroendocrine and undifferentiated carcinomas. The level of bcl-2 expression in squamous cell carcinomas was found higher than in references. Among tumors with cell death there was an inverted relation of bcl-2 and p53 expression (high/low) in neuroendocrine carcinomas but both of them were mostly negative in squamous cell carcinomas. A more frequent 2-year-survival of squamous cell carcinomas was verified for bcl-2 positive tumors and newly for p53 positive squamous cell carcinomas. Evaluation of the expression of p53, p21 and bcl-2 in lung carcinomas is so equivocal that its prognostic usage was found to be only complementary to the direct immunohistochemical investigation of the growth activities.

Cytokeratins and lung carcinomas

BACKGROUND

Recently, cytokeratins (CK) were studied as tumor markers for many carcinomas. In lung cancer they appeared to be useful in distinguishing primary from secondary tumors, in histological typing as well as in evaluating patient's prognosis. However, the results have yet to be conclusive. In this study, expression of CK7, CK10/13, CK18, CK19, CK20 was investigated in a group of 72 surgically resected specimens of lung including 31 adenocarcinomas, 30 squamous cell carcinomas and 11 neuroendocrine carcinomas. Cytokeratin immunophenotypes were analyzed in comparison to histological characteristics of tumors, TNM stages and patients survival.

RESULTS

CK7, CK10/13 and CK18 can be used in distinguishing the lung adenocarcinomas from the lung squamous cell carcinomas: CK7(+), CK10/13(-), CK18(+) for adenocarcinomas; CK7(-), CK10/13(+), CK18(-) for squamous cell carcinomas. Relatively higher CK7 and CK18 immunostaining rates of the squamous cell carcinomas with high keratinization, with high percentage of dead cells and with late stages of disease suggested their prognostic significance but it was not confirmed when comparing different survival groups. Both adenocarcinomas and squamous cell carcinomas were stained strongly with antibody against CK19 (90.3% and 86.7% respectively) but much less with anti-CK20 antibody (9.7% and 3.3% respectively). In general, neuroendocrine tumors of the lung were non-reactive for these cytokeratins except CK18, among them all carcinoid tumors expressed CK18 abundantly.

[Expression of the nm 23 gene in pulmonary carcinomas]

Gene nm 23 may have an antimetastatic function but relevant data in the literature are ambiguous even in the same types of malignant tumors. In a group of 77 lung carcinomas there was not found any relation of gene nm 23 expression to the histologic type of tumor or the level of its differentiation and to the finding of metastases in resected lung materials either. Adenocarcinomas showed a negative relation of nm 23 expression to later occurrence of metastases and to a decreased survival of patients which squamous, neuroendocrine and undifferentiated carcinomas did not. Unexpected low expression or negativity of nm 23 in tumors of little progression and rare high positivities in some lung carcinomas with metastases could be explained by gene nm 23 mutations or inactivation. Results of the study do not encourage the usage of nm 23 as a reliable prognostic marker in lung carcinomas.