Smoking behaviour among adult patients presenting to health facilities in four provinces of Vietnam.

BACKGROUND: Attendance at healthcare facilities provides an opportunity for smoking cessation interventions. However, the smoking behaviours of patients seeking healthcare in Vietnam are not well-understood. We aimed to evaluate behaviours related to smoking among patients presenting to health facilities in Vietnam. METHODS: We conducted a cross-sectional study in 4 provinces of Vietnam. Consecutive patients aged ≥15 years presenting to 46 health facilities were assessed. Current smokers were randomly selected to complete a full survey about smoking behaviour, quit attempts, and preparedness to quit. RESULTS: Among 11,245 patients who sought healthcare, the prevalence of current smoking was 18.6% (95% CI: 17.8-19.4%) overall, 34.6% (95% CI: 33.2-36.0%) among men and 1.1% (95% CI: 0.8-1.3%) among women. Current smokers who were asked about smoking by healthcare providers in the last 12 months were more likely to make quit attempts than those not asked (40.6% vs 31.8%, p = 0.017). Current smokers who attempted to quit in the past 12 months made limited use of cessation aids: counselling (1.9%) and nicotine replacement therapy (10%). A higher proportion of patients wanted to quit in the next month at national/provincial hospitals (30.3%) than those visiting district hospitals (11.3%, p < 0.001) and commune health centres (11.1%, p = 0.004). CONCLUSIONS: Smoking is common among male patients presenting to healthcare facilities in Vietnam. Formal smoking cessation supports are generally not used or offered. This population is likely to benefit from routine smoking cessation interventions that are integrated within the routine healthcare delivery system.

Treatment correlates of successful outcomes in pulmonary multidrug-resistant tuberculosis: an individual patient data meta-analysis.

BACKGROUND: Treatment outcomes for multidrug-resistant tuberculosis remain poor. We aimed to estimate the association of treatment success and death with the use of individual drugs, and the optimal number and duration of treatment with those drugs in patients with multidrug-resistant tuberculosis. METHODS: In this individual patient data meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library to identify potentially eligible observational and experimental studies published between Jan 1, 2009, and April 30, 2016. We also searched reference lists from all systematic reviews of treatment of multidrug-resistant tuberculosis published since 2009. To be eligible, studies had to report original results, with end of treatment outcomes (treatment completion [success], failure, or relapse) in cohorts of at least 25 adults (aged >18 years). We used anonymised individual patient data from eligible studies, provided by study investigators, regarding clinical characteristics, treatment, and outcomes. Using propensity score-matched generalised mixed effects logistic, or linear regression, we calculated adjusted odds ratios and adjusted risk differences for success or death during treatment, for specific drugs currently used to treat multidrug-resistant tuberculosis, as well as the number of drugs used and treatment duration. FINDINGS: Of 12 030 patients from 25 countries in 50 studies, 7346 (61%) had treatment success, 1017 (8%) had failure or relapse, and 1729 (14%) died. Compared with failure or relapse, treatment success was positively associated with the use of linezolid (adjusted risk difference 0·15, 95% CI 0·11 to 0·18), levofloxacin (0·15, 0·13 to 0·18), carbapenems (0·14, 0·06 to 0·21), moxifloxacin (0·11, 0·08 to 0·14), bedaquiline (0·10, 0·05 to 0·14), and clofazimine (0·06, 0·01 to 0·10). There was a significant association between reduced mortality and use of linezolid (-0·20, -0·23 to -0·16), levofloxacin (-0·06, -0·09 to -0·04), moxifloxacin (-0·07, -0·10 to -0·04), or bedaquiline (-0·14, -0·19 to -0·10). Compared with regimens without any injectable drug, amikacin provided modest benefits, but kanamycin and capreomycin were associated with worse outcomes. The remaining drugs were associated with slight or no improvements in outcomes. Treatment outcomes were significantly worse for most drugs if they were used despite in-vitro resistance. The optimal number of effective drugs seemed to be five in the initial phase, and four in the continuation phase. In these adjusted analyses, heterogeneity, based on a simulated I2 method, was high for approximately half the estimates for specific drugs, although relatively low for number of drugs and durations analyses. INTERPRETATION: Although inferences are limited by the observational nature of these data, treatment outcomes were significantly better with use of linezolid, later generation fluoroquinolones, bedaquiline, clofazimine, and carbapenems for treatment of multidrug-resistant tuberculosis. These findings emphasise the need for trials to ascertain the optimal combination and duration of these drugs for treatment of this condition. FUNDING: American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Tuberculosis in Newborns: The Lessons of the "Lübeck Disaster" (1929-1933).

In an accident later known as the Lübeck disaster, 251 neonates were orally given three doses of the new Bacille Calmette-Guérin (BCG) antituberculosis (TB) vaccine contaminated with Mycobacterium tuberculosis. A total of 173 infants developed clinical or radiological signs of TB but survived the infection, while 72 died from TB. While some blamed the accident on BCG itself by postulating reversion to full virulence, such a possibility was conclusively disproven. Rather, by combining clinical, microbiological, and epidemiological data, the chief public health investigator Dr. A. Moegling concluded that the BCG vaccine had been contaminated with variable amounts of fully virulent M. tuberculosis. Here, we summarize the conclusions drawn by Moegling and point out three lessons that can be learned. First, while mortality was high (approximately 29%), the majority of neonates inoculated with M. tuberculosis eventually overcame TB disease. This shows the high constitutional resistance of humans to the bacillus. Second, four semiquantitative levels of contamination were deduced by Moegling from the available data. While at low levels of M. tuberculosis there was a large spread of clinical phenotypes reflecting a good degree of innate resistance to TB, at the highest dose, the majority of neonates were highly susceptible to TB. This shows the dominating role of dose for innate resistance to TB. Third, two infants inoculated with the lowest dose nevertheless died of TB, and their median time from inoculation to death was substantially shorter than for those who died after inoculation with higher doses. This suggests that infants who developed disease after low dose inoculation are those who are most susceptible to the disease. We discuss some implications of these lessons for current study of genetic susceptibility to TB.

Surgery as an Adjunctive Treatment for Multidrug-Resistant Tuberculosis: An Individual Patient Data Metaanalysis.

BACKGROUND: Medical treatment for multidrug-resistant (MDR)-tuberculosis is complex, toxic, and associated with poor outcomes. Surgical lung resection may be used as an adjunct to medical therapy, with the intent of reducing bacterial burden and improving cure rates. We conducted an individual patient data metaanalysis to evaluate the effectiveness of surgery as adjunctive therapy for MDR-tuberculosis. METHODS: Individual patient data, was obtained from the authors of 26 cohort studies, identified from 3 systematic reviews of MDR-tuberculosis treatment. Data included the clinical characteristics and medical and surgical therapy of each patient. Primary analyses compared treatment success (cure and completion) to a combined outcome of failure, relapse, or death. The effects of all forms of resection surgery, pneumonectomy, and partial lung resection were evaluated. RESULTS: A total of 4238 patients from 18 surgical studies and 2193 patients from 8 nonsurgical studies were included. Pulmonary resection surgery was performed on 478 patients. Partial lung resection surgery was associated with improved treatment success (adjusted odds ratio [aOR], 3.0; 95% confidence interval [CI], 1.5-5.9; I(2)R, 11.8%), but pneumonectomy was not (aOR, 1.1; 95% CI, .6-2.3; I(2)R, 13.2%). Treatment success was more likely when surgery was performed after culture conversion than before conversion (aOR, 2.6; 95% CI, 0.9-7.1; I(2)R, 0.2%). CONCLUSIONS: Partial lung resection, but not pneumonectomy, was associated with improved treatment success among patients with MDR-tuberculosis. Although improved outcomes may reflect patient selection, partial lung resection surgery after culture conversion may improve treatment outcomes in patients who receive optimal medical therapy.

Fluoroquinolone Therapy for the Prevention of Multidrug-Resistant Tuberculosis in Contacts. A Cost-Effectiveness Analysis.

RATIONALE: Fluoroquinolone (FQN) therapy of latent tuberculosis infection among contacts of individuals with multidrug-resistant tuberculosis (MDR-TB) is controversial. OBJECTIVES: To determine the potential benefits, risks (including acquired FQN resistance), and cost-effectiveness of FQN therapy to prevent TB in contacts of individuals with MDR-TB. METHODS: We used decision analysis to estimate costs and outcomes associated with no therapy compared with a 6-month course of daily FQN therapy to treat latent TB infection in contacts of individuals with MDR-TB. Outcomes modeled were the incidence of MDR-TB, MDR-TB with FQN resistance, TB-related death, quality-adjusted life years, and health system costs. MEASUREMENTS AND MAIN RESULTS: FQN preventive therapy resulted in health system savings, lower incidence of MDR-TB, and lower mortality than no treatment. We found the incidence of MDR-TB with acquired FQN resistance would also be lower with FQN therapy of infected contacts. CONCLUSIONS: In our model, FQN preventive therapy resulted in substantial health system savings and in reduced mortality, incidence of MDR-TB, and incidence of acquired FQN-resistant disease as well as improved quality of life. FQN therapy remained cost saving with improved outcomes even if the effectiveness of therapy in preventing MDR-TB was as low as 10%.

Contact investigation for tuberculosis: a systematic review and meta-analysis.

Investigation of contacts of patients with tuberculosis (TB) is a priority for TB control in high-income countries, and is increasingly being considered in resource-limited settings. This review was commissioned for a World Health Organization Expert Panel to develop global contact investigation guidelines. We performed a systematic review and meta-analysis of all studies reporting the prevalence of TB and latent TB infection, and the annual incidence of TB among contacts of patients with TB. After screening 9,555 titles, we included 203 published studies. In 95 studies from low- and middle-income settings, the prevalence of active TB in all contacts was 3.1% (95% CI 2.2-4.4%, I(2)=99.4%), microbiologically proven TB was 1.2% (95% CI 0.9-1.8%, I(2)=95.9%), and latent TB infection was 51.5% (95% CI 47.1-55.8%, I(2)=98.9%). The prevalence of TB among household contacts was 3.1% (95% CI 2.1-4.5%, I(2)=98.8%) and among contacts of patients with multidrug-resistant or extensively drug-resistant TB was 3.4% (95% CI 0.8-12.6%, I(2)=95.7%). Incidence was greatest in the first year after exposure. In 108 studies from high-income settings, the prevalence of TB among contacts was 1.4% (95% CI 1.1-1.8%, I(2)=98.7%), and the prevalence of latent infection was 28.1% (95% CI 24.2-32.4%, I(2)=99.5%). There was substantial heterogeneity among published studies. Contacts of TB patients are a high-risk group for developing TB, particularly within the first year. Children <5 yrs of age and people living with HIV are particularly at risk. Policy recommendations must consider evidence of the cost-effectiveness of various contact tracing strategies, and also incorporate complementary strategies to enhance case finding.

mHealth application for improving treatment outcomes for patients with multidrug-resistant tuberculosis in Vietnam: an economic evaluation protocol for the V-SMART trial.

INTRODUCTION: The Strengthen the Management of Multidrug-Resistant Tuberculosis in Vietnam (V-SMART) trial is a randomised controlled trial of using mobile health (mHealth) technologies to improve adherence to medications and management of adverse events (AEs) in people with multidrug-resistant tuberculosis (MDR-TB) undergoing treatment in Vietnam. This economic evaluation seeks to quantify the cost-effectiveness of this mHealth intervention from a healthcare provider and societal perspective. METHODS AND ANALYSIS: The V-SMART trial will recruit 902 patients treated for MDR-TB across seven participating provinces in Vietnam. Participants in both intervention and control groups will receive standard community-based therapy for MDR-TB. Participants in the intervention group will also have a purpose-designed App installed on their smartphones to report AEs to health workers and to facilitate timely management of AEs. This economic evaluation will compare the costs and health outcomes between the intervention group (mHealth) and the control group (standard of care). Costs associated with delivering the intervention and health service utilisation will be recorded, as well as patient out-of-pocket costs. The health-related quality of life (HRQoL) of study participants will be captured using the 36-Item Short Form Survey (SF-36) questionnaire and used to calculate quality-adjusted life-years (QALYs). Incremental cost-effectiveness ratios (ICERs) will be based on the primary outcome (proportion of patients with treatment success after 24 months) and QALYs gained. Sensitivity analysis will be conducted to test the robustness of the ICERs. A budget impact analysis will be conducted from a payer perspective to provide an estimate of the total budget required to scale-up delivery of the intervention. ETHICS AND DISSEMINATION: Ethical approval for the study was granted by the University of Sydney Human Research Ethics Committee (2019/676), the Scientific Committee of the Ministry of Science and Technology, Vietnam (08/QD-HDQL-NAFOSTED) and the Institutional Review Board of the National Lung Hospital, Vietnam (13/19/CT-HDDD). Study findings will be published in peer-reviewed journals and conference proceedings. TRIAL REGISTRATION NUMBER: ACTRN12620000681954.

Active case finding in contacts of people with tuberculosis.

BACKGROUND: Tuberculosis is a major global health challenge that is caused by a bacteria which is spread by airborne droplets. Mostly patients are identified in high-burden countries when they visit health care facilities ('passive case finding'). Contacts of tuberculosis patients are a high-risk group for developing the disease. Actively screening contacts of people with confirmed tuberculosis may improve case detection rates and control of the disease. OBJECTIVES: This study aims to compare whether active case finding among contacts of people with confirmed tuberculosis increases case detection compared to usual practice. SEARCH STRATEGY: In April 2011 we searched CENTRAL (The Cochrane Library 2011, Issue 2), MEDLINE, EMBASE, LILACS and mRCT. We also checked article reference lists, the International Journal of Tuberculosis and Lung Disease and contacted relevant researchers and organizations. SELECTION CRITERIA: Randomized and quasi-randomized trials of active case finding to detect tuberculosis disease among close and casual contacts of patients with microbiologically proven pulmonary tuberculosis (by sputum smear and/or culture). DATA COLLECTION AND ANALYSIS: Two authors independently assessed eligibility and the methodological quality of the trials that were extracted using a search method that was outlined previously. MAIN RESULTS: No trials met the inclusion criteria for this review. One RCT did test the effect of active case finding in contacts, but the intervention in that trial also included screening for, and treatment of, LTBI in contacts; and the separate effect of active case finding could not be estimated. AUTHORS' CONCLUSIONS: There are currently insufficient data from randomized controlled trials or quasi-randomized controlled trials to evaluate the effect of active case finding for tuberculosis among contacts of patients with confirmed disease. While observational studies show that contacts have a higher risk of developing tuberculosis than the general population, further research is needed to determine whether active case finding among contacts significantly increases case detection rates.

A syndromic approach to assess diagnosis and management of patients presenting with respiratory symptoms to healthcare facilities in Vietnam.

BACKGROUND: The aim of the study was to establish syndromic diagnoses in patients presenting with respiratory symptoms to healthcare facilities in Vietnam and to compare the diagnoses with facility-level clinical diagnoses and treatment decisions. METHODS: A representative sample of patients aged ≥5 years, presenting with dyspnoea, cough, wheezing, and/or chest tightness to healthcare facilities in four provinces of Vietnam were systematically evaluated. Eight common syndromes were defined using data obtained. RESULTS: We enrolled 977 subjects at 39 facilities. We identified fixed airflow limitation (FAL) in 198 (20.3%) patients and reversible airflow limitation (RAL) in 26 (2.7%) patients. Patients meeting the criteria for upper respiratory tract infection (URTI) alone constituted 160 (16.4%) patients and 470 (48.1%) did not meet the criteria for any of the syndromes. Less than half of patients with FAL were given long-acting bronchodilators. A minority of patients with either RAL or FAL with eosinophilia were prescribed inhaled corticosteroids. Antibiotics were given to more than half of all patients, even among those with URTI alone. CONCLUSION: This study identified a substantial discordance between prescribed treatment, clinician diagnosis and a standardised syndromic diagnosis among patients presenting with respiratory symptoms. Increased access to spirometry and implementation of locally relevant syndromic approaches to management may help to improve patient care in resource-limited settings.

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.

Propensity Score-Based Approaches to Confounding by Indication in Individual Patient Data Meta-Analysis: Non-Standardized Treatment for Multidrug Resistant Tuberculosis.

BACKGROUND: In the absence of randomized clinical trials, meta-analysis of individual patient data (IPD) from observational studies may provide the most accurate effect estimates for an intervention. However, confounding by indication remains an important concern that can be addressed by incorporating individual patient covariates in different ways. We compared different analytic approaches to account for confounding in IPD from patients treated for multi-drug resistant tuberculosis (MDR-TB). METHODS: Two antibiotic classes were evaluated, fluoroquinolones--considered the cornerstone of effective MDR-TB treatment--and macrolides, which are known to be safe, yet are ineffective in vitro. The primary outcome was treatment success against treatment failure, relapse or death. Effect estimates were obtained using multivariable and propensity-score based approaches. RESULTS: Fluoroquinolone antibiotics were used in 28 included studies, within which 6,612 patients received a fluoroquinolone and 723 patients did not. Macrolides were used in 15 included studies, within which 459 patients received this class of antibiotics and 3,670 did not. Both standard multivariable regression and propensity score-based methods resulted in similar effect estimates for early and late generation fluoroquinolones, while macrolide antibiotics use was associated with reduced treatment success. CONCLUSIONS: In this individual patient data meta-analysis, standard multivariable and propensity-score based methods of adjusting for individual patient covariates for observational studies yielded produced similar effect estimates. Even when adjustment is made for potential confounding, interpretation of adjusted estimates must still consider the potential for residual bias.

Bridging the gap between evidence and policy for infectious diseases: How models can aid public health decision-making.

The dominant approach to decision-making in public health policy for infectious diseases relies heavily on expert opinion, which often applies empirical evidence to policy questions in a manner that is neither systematic nor transparent. Although systematic reviews are frequently commissioned to inform specific components of policy (such as efficacy), the same process is rarely applied to the full decision-making process. Mathematical models provide a mechanism through which empirical evidence can be methodically and transparently integrated to address such questions. However, such models are often considered difficult to interpret. In addition, models provide estimates that need to be iteratively re-evaluated as new data or considerations arise. Using the case study of a novel diagnostic for tuberculosis, a framework for improved collaboration between public health decision-makers and mathematical modellers that could lead to more transparent and evidence-driven policy decisions for infectious diseases in the future is proposed. The framework proposes that policymakers should establish long-term collaborations with modellers to address key questions, and that modellers should strive to provide clear explanations of the uncertainty of model structure and outputs. Doing so will improve the applicability of models and clarify their limitations when used to inform real-world public health policy decisions.

Inadequate Diet Is Associated with Acquiring Mycobacterium tuberculosis Infection in an Inuit Community. A Case-Control Study.

BACKGROUND: Tuberculosis predominantly affects socioeconomically disadvantaged communities. The extent to which specific dietary and lifestyle factors contribute to tuberculosis susceptibility has not been established. METHODS: A total of 200 residents of a village in Northern Quebec were investigated during a tuberculosis outbreak and identified to have active tuberculosis, latent tuberculosis infection, or neither. Participants completed questionnaires about their intake of food from traditional and commercial sources, and provided blood samples. Adults were asked about recent smoking and drug and alcohol intake. Nutritional adequacy was evaluated with reference to North American standards. Multiple dietary, lifestyle, and housing factors were combined in a logistic regression model evaluating the contributions of each to disease and infection. FINDINGS: After adjusting for potential confounding, new infection was associated with inadequate intake of fruit and vegetables (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.03-4.3), carbohydrates (OR, 4.4; 95% CI, 1.2-16.3), and certain vitamins and minerals. A multivariable model, combining nutrition, housing, and lifestyle factors, found associations between new infection and inadequate fruit and vegetable intake (OR, 2.3; 95% CI, 1.0-5.1), living in the same house as a person with smear-positive tuberculosis (OR, 14.7; 95% CI, 1.6-137.3), and visiting a community gathering house (OR, 3.7; 95% CI, 1.7-8.3). Current smoking was associated with new infection (OR, 9.4; 95% CI, 1.2-72) among adults completing a detailed lifestyle survey. INTERPRETATION: Inadequate nutrition was associated with increased susceptibility to infection, but not active tuberculosis. Interventions addressed at improving nutrition may reduce susceptibility to infection in settings where access to healthy foods is limited.

Polymorphisms of SP110 are associated with both pulmonary and extra-pulmonary tuberculosis among the Vietnamese.

BACKGROUND: Tuberculosis (TB) is an infectious disease that remains a major cause of morbidity and mortality worldwide, yet the reasons why only 10% of people infected with Mycobacterium tuberculosis go on to develop clinical disease are poorly understood. Genetically determined variation in the host immune response is one factor influencing the response to M. tuberculosis. SP110 is an interferon-responsive nuclear body protein with critical roles in cell cycling, apoptosis and immunity to infection. However association studies of the gene with clinical TB in different populations have produced conflicting results. METHODS: To examine the importance of the SP110 gene in immunity to TB in the Vietnamese we conducted a case-control genetic association study of 24 SP110 variants, in 663 patients with microbiologically proven TB and 566 unaffected control subjects from three tertiary hospitals in northern Vietnam. RESULTS: Five SNPs within SP110 were associated with all forms of TB, including four SNPs at the C terminus (rs10208770, rs10498244, rs16826860, rs11678451) under a dominant model and one SNP under a recessive model, rs7601176. Two of these SNPs were associated with pulmonary TB (rs10208770 and rs16826860) and one with extra-pulmonary TB (rs10498244). CONCLUSION: SP110 variants were associated with increased susceptibility to both pulmonary and extra-pulmonary TB in the Vietnamese. Genetic variants in SP110 may influence macrophage signaling responses and apoptosis during M. tuberculosis infection, however further research is required to establish the mechanism by which SP110 influences immunity to tuberculosis infection.

A Review of the Evidence for Using Bedaquiline (TMC207) to Treat Multi-Drug Resistant Tuberculosis.

Existing therapies for multi-drug resistant tuberculosis (MDR-TB) have substantial limitations, in terms of their effectiveness, side-effect profile, and complexity of administration. Bedaquiline is a novel diarylquinoline antibiotic that has recently been investigated as an adjunct to existing therapies for MDR-TB. Currently, limited clinical data are available to evaluate the drug's safety and effectiveness. In two small randomized-controlled clinical studies, bedaquiline given for 8 or 24 weeks has been shown to improve surrogate microbiological markers of treatment response, but trials have not yet evaluated its impact on clinical failure and relapse. Safety concerns include an increased mortality in the bedaquiline arm of one study, an increased incidence of QT segment prolongation on electrocardiogram, and hepatotoxicity. Until further research data are available, the use of bedaquiline should be confined to settings where carefully selected patients can be closely monitored.

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).