Tuberculosis screening of immigrants to low-prevalence countries. A cost-effectiveness analysis

Tuberculosis prevention: current strategies and future directions

BACKGROUND

An estimated one fourth of the world's population is infected with Mycobacterium tuberculosis, and 5-10% of those infected develop tuberculosis in their lifetime. Preventing tuberculosis is one of the most underutilized but essential components of curtailing the tuberculosis epidemic. Moreover, current evidence illustrates that tuberculosis manifestations occur along a dynamic spectrum from infection to disease rather than a binary state as historically conceptualized. Elucidating determinants of transition between these states is crucial to decreasing the tuberculosis burden and reaching the END-TB Strategy goals as defined by the WHO. Vaccination, detection of infection, and provision of preventive treatment are key elements of tuberculosis prevention.

OBJECTIVES

This review provides a comprehensive summary of recent evidence and state-of-the-art updates on advancements to prevent tuberculosis in various settings and high-risk populations.

SOURCES

We identified relevant studies in the literature and synthesized the findings to provide an overview of the current state of tuberculosis prevention strategies and latest research developments.

CONTENT

We present the current knowledge and recommendations regarding tuberculosis prevention, with a focus on M. bovis Bacille-Calmette-Guérin vaccination and novel vaccine candidates, tests for latent infection with M. tuberculosis, regimens available for tuberculosis preventive treatment and recommendations in low- and high-burden settings.

IMPLICATIONS

Effective tuberculosis prevention worldwide requires a multipronged approach that addresses social determinants, and improves access to tuberculosis detection and to new short tuberculosis preventive treatment regimens. Robust collaboration and innovative research are needed to reduce the global burden of tuberculosis and develop new detection tools, vaccines, and preventive treatments that serve all populations and ages.

The cascade of care for pregnant women with latent tuberculosis infection in a high-income country

BACKGROUND

Pregnant women have an increased risk of developing active tuberculosis (TB). The Public Health Agency of Sweden recommends screening of active TB and latent tuberculosis infection (LTBI) among pregnant women from countries with high TB incidence at Maternal Health Care (MHC) clinics. In Östergötland County, Sweden, a screening program has been active since 2013. The aim of this study was to evaluate this screening program and the cascade of care for LTBI among pregnant women in Östergötland county.

METHODS

Data were obtained from pregnant women screened for TB at MHC clinics and subsequently referred to the pulmonary medicine clinic or the clinic of infectious diseases in Östergötland County between 2013 and 2018. The Public Health Agency of Sweden's national database for active TB was used to analyse if any women developed active TB up to two years after the screening process.

RESULTS

A total of 439 women were included. Nine cases of active TB were discovered during the screening process and two developed active TB afterward. 177 women were recommended LTBI treatment and variables significantly associated with a decreased likelihood of being recommended treatment were increasing age, time in Sweden, and parity. 137 women received and 112 (82%) completed treatment. 14 women discontinued treatment due to adverse effects.

CONCLUSION

Screening of pregnant women from countries with high TB incidence at MHC clinics led to the discovery of several cases of active TB. The completion rate of LTBI treatment was high and few discontinued due to adverse effects.

Invited Commentary: The Role of Tuberculosis Screening Among Migrants to Low-Incidence Settings in (Not) Achieving Elimination

The cost-effectiveness of migrant tuberculosis prevention programs is highly relevant to many countries with low tuberculosis incidence as they attempt to eliminate the disease. Dale et al. (Am J Epidemiol. 2022;191(2):255-270) evaluated strategies for tuberculosis infection screening and treatment among new migrants to Australia. Screening for infection before migration, and then administering preventive treatment after arrival, was more cost-effective than performing both screening and treatment after arrival. From the Australian health payer perspective, the improved cost-effectiveness of premigration screening partly reflected the shift of screening costs to migrants, which may raise ethical concerns. Key sensitivity analyses highlighted the influence of health disutility associated with tuberculosis preventive treatment, and of posttreatment sequelae of tuberculosis disease. Both considerations warrant greater attention in future research. For all strategies, the impact on tuberculosis incidence among migrants was modest (<15%), suggesting enhanced migrant screening will not achieve tuberculosis elimination in low-incidence settings. This emphasizes the need to increase investment and effort in global tuberculosis prevention and care, which will ultimately reduce the prevalence of tuberculosis infection and therefore the risk of tuberculosis disease among migrants. Such efforts will benefit high and low tuberculosis incidence countries alike, and advance all countries further toward tuberculosis elimination.

Cost-effectiveness of targeted screening for active pulmonary tuberculosis among asylum-seekers: A modelling study with screening data from a German federal state (2002-2015)

Screening asylum-seekers for active pulmonary tuberculosis is common practice among many European countries with low incidence of tuberculosis. The reported yields vary substantially, partly due to the heterogeneous and dynamic nature of asylum-seeking populations. Rather than screening all new arrivals (indiscriminate screening), a few countries apply targeted screening based on incidence of tuberculosis in asylum-seekers' country of origin. However, evaluations of its cost-effectiveness have been scarce. The aim of this modelling study was to assess whether the introduction of a screening threshold based on the tuberculosis incidence in the country of origin is sensible from an economic perspective. To this end, we compare the current, indiscriminate screening policy for pulmonary tuberculosis in Germany with a hypothetical targeted screening programme using several potential screening thresholds based on WHO-reported incidence of tuberculosis in countries of origin. Screening data is taken from a large German federal state over 14 years (2002-2015). Incremental cost-effectiveness is measured as cost per case found and cost per case prevented. Our analysis shows that incremental cost-effectiveness ratios (ICERs) of screening asylum-seekers from countries with an incidence of 50 to 250/100,000 range between 15,000€ and 17,000€ per additional case found when compared to lower thresholds. The ICER for screening asylum-seekers from countries with an incidence <50/100,000 is 112,000€ per additional case found. Costs per case prevented show a similar increase in costs. The high cost per case found and per case prevented at the <50/100,000 threshold scenario suggests this threshold to be a sensible cut-off for targeted screening. Acknowledging that no screening measure can find all cases of tuberculosis, and that reactivation of latent infections makes up a large proportion of foreign-born cases, targeting asylum-seekers from countries with an incidence above 50/100,000 is likely to be a more reasonable screening measure for the prevention and control of tuberculosis than indiscriminate screening measures.

Cost-effectiveness of Latent Tuberculosis Infection Screening before Immigration to Low-Incidence Countries

Prospective migrants to countries where the incidence of tuberculosis (TB) is low (low-incidence countries) receive TB screening; however, screening for latent TB infection (LTBI) before immigration is rare. We evaluated the cost-effectiveness of mandated and sponsored preimmigration LTBI screening for migrants to low-incidence countries. We used discrete event simulation to model preimmigration LTBI screening coupled with postarrival follow-up and treatment for those who test positive. Preimmigration interferon-gamma release assay screening and postarrival rifampin treatment was preferred in deterministic analysis. We calculated cost per quality-adjusted life-year gained for migrants from countries with different TB incidences. Our analysis provides evidence of the cost-effectiveness of preimmigration LTBI screening for migrants to low-incidence countries. Coupled with research on sustainability, acceptability, and program implementation, these results can inform policy decisions.

The effectiveness and cost-effectiveness of screening for active tuberculosis among migrants in the EU/EEA: a systematic review

: The foreign-born population make up an increasing and large proportion of tuberculosis (TB) cases in European Union/European Economic Area (EU/EEA) low-incidence countries and challenge TB elimination efforts. Methods: We conducted a systematic review to determine effectiveness (yield and performance of chest radiography (CXR) to detect active TB, treatment outcomes and acceptance of screening) and a second systematic review on cost-effectiveness of screening for active TB among migrants living in the EU/EEA. Results: We identified six systematic reviews, one report and three individual studies that addressed our aims. CXR was highly sensitive (98%) but only moderately specific (75%). The yield of detecting active TB with CXR screening among migrants was 350 per 100,000 population overall but ranged widely by host country (110–2,340), migrant type (170–1,192), TB incidence in source country (19–336) and screening setting (220–1,720). The CXR yield was lower (19.6 vs 336/100,000) and the numbers needed to screen were higher (5,076 vs 298) among migrants from source countries with lower TB incidence (≤ 50 compared with ≥ 350/100,000). Cost-effectiveness was highest among migrants originating from high (> 120/100,000) TB incidence countries. The foreign-born had similar or better TB treatment outcomes than those born in the EU/EEA. Acceptance of CXR screening was high (85%) among migrants. Discussion: Screening programmes for active TB are most efficient when targeting migrants from higher TB incidence countries. The limited number of studies identified and the heterogeneous evidence highlight the need for further data to inform screening programmes for migrants in the EU/EEA.

The effectiveness and cost-effectiveness of screening for latent tuberculosis among migrants in the EU/EEA: a systematic review

Migrants account for a large and growing proportion of tuberculosis (TB) cases in low-incidence countries in the European Union/European Economic Area (EU/EEA) which are primarily due to reactivation of latent TB infection (LTBI). Addressing LTBI among migrants will be critical to achieve TB elimination. Methods: We conducted a systematic review to determine effectiveness (performance of diagnostic tests, efficacy of treatment, uptake and completion of screening and treatment) and a second systematic review on cost-effectiveness of LTBI screening programmes for migrants living in the EU/EEA. Results: We identified seven systematic reviews and 16 individual studies that addressed our aims. Tuberculin skin tests and interferon gamma release assays had high sensitivity (79%) but when positive, both tests poorly predicted the development of active TB (incidence rate ratio: 2.07 and 2.40, respectively). Different LTBI treatment regimens had low to moderate efficacy but were equivalent in preventing active TB. Rifampicin-based regimens may be preferred because of lower hepatotoxicity (risk ratio = 0.15) and higher completion rates (82% vs 69%) compared with isoniazid. Only 14.3% of migrants eligible for screening completed treatment because of losses along all steps of the LTBI care cascade. Limited economic analyses suggest that the most cost-effective approach may be targeting young migrants from high TB incidence countries. Discussion: The effectiveness of LTBI programmes is limited by the large pool of migrants with LTBI, poorly predictive tests, long treatments and a weak care cascade. Targeted LTBI programmes that ensure high screening uptake and treatment completion will have greatest individual and public health benefit.

Post-migration follow-up programme for migrants at increased risk of developing tuberculosis: a cohort study

Following pre-migration screening for tuberculosis (TB), migrants who are deemed to be at a high risk of developing TB must attend post-entry follow-up in Australia. We aimed to evaluate the effectiveness of post-migration TB follow-up in the state of New South Wales to diagnose TB in these high-risk migrants. In this retrospective cohort study, we assessed the risk of TB in migrants who arrived in New South Wales between 2000 and 2015 and were referred for post-migration follow-up. Clinical notes were examined for a nested cohort to determine whether TB was diagnosed via the follow-up programme or via passive case finding. Of the 32 550 migrants referred for follow-up, 428 (1.3%) developed TB. The incidence of TB was 436 per 100 000 person-years (95% CI 384-491 per 100 000 person-years) in the first 2 years after arrival and 128 per 100 000 person-years (95% CI 116-140 per 100 000 person-years) over the mean study observation period of 10.3 years. An estimated 63% of cases were diagnosed via follow-up. TB notifications occurred 0.55 years earlier since time of arrival in Australia in migrants who attended follow-up than in those who did not. Post-migration follow-up detected 63% of TB cases in high-risk migrants and potentially prevented delay of TB diagnosis.

Predicting pulmonary tuberculosis in immigrants: a retrospective cohort study

Our objective was to investigate whether pulmonary tuberculosis (PTB) can be predicted from features of a targeted medical history and basic laboratory investigations in immigrants.

A retrospective cohort of 391 foreign-born adults referred to the Edmonton Tuberculosis Clinic (Edmonton, AB, Canada) was studied using multiple logistic regression analysis to predict PTB. Seven characteristics of disease were used as explanatory variables. Cross-validation assessed performance. Each predictor was tested on two outcomes: “culture-positive” and “smear-positive”. Receiver operating characteristic (ROC) curves were generated and the area under the ROC curve (AUC) was quantified.

Symptoms, subacute duration of symptoms, risk factors for reactivation of latent TB infection and anaemia were all associated with a positive culture (adjusted OR 1.79, 2.24, 1.72 and 2.28, respectively; p<0.05). Symptoms, inappropriate prescription of broad-spectrum antibiotics and a “typical” chest radiograph were associated with smear-positive PTB (adjusted OR 2.91, 1.55 and 12.34, respectively; p<0.05). ROC curve analysis was used to test each model, yielding AUC=0.91 for the outcome “culture-positive” disease and AUC=0.94 for the outcome “smear-positive” disease.

PTB among the foreign-born can be predicted from a targeted medical history and basic laboratory investigations, raising the threshold of suspicion in settings where the disease is relatively rare.

In high-income, low tuberculosis incidence countries, certain clinical characteristics should raise the threshold of suspicion to confirm a timely diagnosishttp://ow.ly/bRDZ30iPurz

Effectiveness of interventions for diagnosis and treatment of tuberculosis in hard-to-reach populations in countries of low and medium tuberculosis incidence: a systematic review

Tuberculosis is over-represented in hard-to-reach (underserved) populations in high-income countries of low tuberculosis incidence. The mainstay of tuberculosis care is early detection of active tuberculosis (case finding), contact tracing, and treatment completion. We did a systematic review with a scoping component of relevant studies published between 1990 and 2015 to update and extend previous National Institute for Health and Care Excellence (NICE) reviews on the effectiveness of interventions for identifying and managing tuberculosis in hard-to-reach populations. The analyses showed that tuberculosis screening by (mobile) chest radiography improved screening coverage and tuberculosis identification, reduced diagnostic delay, and was cost-effective among several hard-to-reach populations. Sputum culture for pre-migration screening and active referral to a tuberculosis clinic improved identification. Furthermore, monetary incentives improved tuberculosis identification and management among drug users and homeless people. Enhanced case management, good cooperation between services, and directly observed therapy improved treatment outcome and compliance. Strong conclusions cannot be drawn because of the heterogeneity of evidence with regard to study population, methodology, and quality.

Tackling TB in low-incidence countries: improving diagnosis and management in vulnerable populations

In low tuberculosis incidence regions, tuberculosis is mainly concentrated among hard-to-reach populations like migrants, homeless people, drug or alcohol abusers, prisoners and people living with HIV. To be able to eliminate tuberculosis from these low incidence regions tuberculosis screening and treatment programs should focus on these hard-to-reach populations. Here we discuss the barriers and facilitators of health care-seeking, interventions improving tuberculosis screening uptake and interventions improving treatment adherence in these hard-to-reach populations.

The impact of migration on tuberculosis epidemiology and control in high-income countries: a review

Tuberculosis (TB) causes significant morbidity and mortality in high-income countries with foreign-born individuals bearing a disproportionate burden of the overall TB case burden in these countries. In this review of tuberculosis and migration we discuss the impact of migration on the epidemiology of TB in low burden countries, describe the various screening strategies to address this issue, review the yield and cost-effectiveness of these programs and describe the gaps in knowledge as well as possible future solutions.The reasons for the TB burden in the migrant population are likely to be the reactivation of remotely-acquired latent tuberculosis infection (LTBI) following migration from low/intermediate-income high TB burden settings to high-income, low TB burden countries.TB control in high-income countries has historically focused on the early identification and treatment of active TB with accompanying contact-tracing. In the face of the TB case-load in migrant populations, however, there is ongoing discussion about how best to identify TB in migrant populations. In general, countries have generally focused on two methods: identification of active TB (either at/post-arrival or increasingly pre-arrival in countries of origin) and secondly, conditionally supported by WHO guidance, through identifying LTBI in migrants from high TB burden countries. Although health-economic analyses have shown that TB control in high income settings would benefit from providing targeted LTBI screening and treatment to certain migrants from high TB burden countries, implementation issues and barriers such as sub-optimal treatment completion will need to be addressed to ensure program efficacy.

Evaluation of a school screening programme for young people from refugee backgrounds

AIM

To describe the development of the Optimising Health and Learning Program, guided by the only available published framework for the delivery of health services to newly arrived refugee children and report on the evaluation of the programme.

METHODS

We conducted process and impact evaluation using a mixed methods approach. The sample was 294 refugee young people enrolled in two Intensive English Centres in New South Wales. We collected quantitative data (demographic and clinical information) as well as qualitative data via focus groups, key informant interviews, surveys and programme documentation. Qualitative data were subjected to thematic analysis; programme documents underwent document review.

RESULTS

There were high levels of programme participation (90%), and the yield from routine health screening was high (80% of participants screened positive for two or more health conditions). All identified programme development strategies were implemented; programme partners and participants reported satisfaction with the programme. Sixteen programme partners were identified with a high level of intersectoral collaboration reported. Significant in-kind contributions and seed funding enabled the uptake of the programme to increase from one to five Intensive English Centres over a 4-year period.

CONCLUSION

Process and impact evaluation identified that the programme was well implemented and met its stated objectives of increasing the detection of health conditions likely to impact on student health and learning; linkage of newly arrived students and their families with primary health care; and coordination of care across primary health and specialist services.

Transnational Record Linkage for Tuberculosis Surveillance and Program Evaluation

OBJECTIVE

Pre-immigration tuberculosis (TB) screening, followed by post-arrival rescreening during the first year, is critical to reducing TB among foreign-born people in the United States. However, existing U.S. public health surveillance is inadequate to monitor TB among immigrants during subsequent years. We developed and tested a novel method for ascertaining post-U.S.-arrival TB outcomes among high-TB-risk immigrant cohorts to improve surveillance.

METHODS

We used a probabilistic record linkage program to link pre-immigration screening records from U.S.-bound immigrants from the Philippines (n=422,593) and Vietnam (n=214,401) with the California TB registry during 2000-2010. We estimated sensitivity using Monte Carlo simulations to account for uncertainty in key inputs. Specificity was evaluated by using a time-stratified approach, which defined false-positives as TB records linked to pre-immigration screening records dated after the person had arrived in the United States.

RESULTS

TB was reported in 4,382 and 2,830 people born in the Philippines and Vietnam, respectively, in California during the study period. Of these TB cases, records for 973 and 452 cases of people born in the Philippines and Vietnam, respectively, were linked to pre-immigration screening records. Sensitivity and specificity of linkage were 89% (90% credible interval [CrI] 83, 97) and 100%, respectively, for the Philippines, and 90% (90% CrI 83, 98) and 99.9%, respectively, for Vietnam.

CONCLUSION

Electronic linkage of pre-immigration screening records to a domestic TB registry was feasible, sensitive, and highly specific in two high-priority immigrant cohorts. Transnational record linkage can be used for program evaluation and routine monitoring of post-U.S.-arrival TB risk among immigrants, but requires interagency data sharing and collaboration.

Cost Effectiveness of Preventive Treatment for Tuberculosis in Special High-Risk Populations

OBJECTIVE

In view of the goal of eliminating tuberculosis (TB) by 2050, economic evaluations of interventions against the development of TB are increasingly requested. Little research has been published on the incremental cost effectiveness of preventative therapy (PT) in groups at high risk for progression from latent TB infection (LTBI) with Mycobacterium TB (MTB) to active disease. A systematic review of studies with a primary focus on model-driving inputs and methodological differences was conducted.

METHODS

A search of MEDLINE, the Cochrane Library and EMBASE to July 2014 was undertaken, and reference lists of eligible articles and relevant reviews were examined.

RESULTS

A total of 876 citations were retrieved, with a total of 24 studies being eligible for inclusion, addressing six high-risk groups other than contact persons. Results varied considerably between studies and countries, and also over time. Although the selected studies generally demonstrated cost effectiveness for PT in HIV-infected subjects and healthcare workers (HCWs), the outcome of these analyses can be questioned in light of recent epidemiologic data. For immigrants from high TB-burden countries, patients with end-stage renal disease, and the immunosuppressed, now defined as further vulnerable groups, no consistent recommendation can be taken from the literature with respect to cost effectiveness of screening and treating LTBI. When the concept of a fixed willingness-to-pay (WTP) threshold as a prerequisite for final categorization was used, the sums ranged between 'no specification' and US$100,000 per quality-adjusted life-year.

CONCLUSIONS

To date, incremental cost-effectiveness analyses on PT in groups at high risk for TB progression, other than contacts, are surprisingly scarce. The variation found between studies likely reflects variations in the major epidemiologic factors, particularly in the estimates on the accuracy of the tuberculin skin test (TST) and interferon-gamma release assays (IGRA) as screening methods used before considering PT. Further research, including explicit evaluation of local epidemiological conditions, test accuracy, and methodology of WTP thresholds, is needed.

Cost-Effectiveness of Screening and Treating Foreign-Born Students for Tuberculosis before Entering the United States

Introduction

The Centers for Disease Control and Prevention is considering implementation of overseas medical screening of student-visa applicants to reduce the numbers of active tuberculosis cases entering the United States.

Objective

To evaluate the costs, cases averted, and cost-effectiveness of screening for, and treating, tuberculosis in United States-bound students from countries with varying tuberculosis prevalence.

Methods

Costs and benefits were evaluated from two perspectives, combined and United States only. The combined perspective totaled overseas and United States costs and benefits from a societal perspective. The United States only perspective was a domestic measure of costs and benefits. A decision tree was developed to determine the cost-effectiveness of tuberculosis screening and treatment from the combined perspective.

Results

From the United States only perspective, overseas screening programs of Chinese and Indian students would prevent the importation of 157 tuberculosis cases annually, and result in $2.7 million in savings. From the combined perspective, screening programs for Chinese students would cost more than $2.8 million annually and screening programs for Indian students nearly $440,000 annually. From the combined perspective, the incremental cost for each tuberculosis case averted by screening Chinese and Indian students was $22,187 and $15,063, respectively. Implementing screening programs for German students would prevent no cases in most years, and would result in increased costs both overseas and in the United States. The domestic costs would occur because public health departments would need to follow up on students identified overseas as having an elevated risk of tuberculosis.

Conclusions

Tuberculosis screening and treatment programs for students seeking long term visas to attend United States schools would reduce the number of tuberculosis cases imported. Implementing screening in high-incidence countries could save the United States millions of dollars annually; however there would be increased costs incurred overseas for students and their families.

Persistent latent tuberculosis reactivation risk in United States immigrants

RATIONALE

Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB.

OBJECTIVES

Estimate reactivation and imported TB in an immigrant cohort.

METHODS

We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001-2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival.

MEASUREMENTS AND MAIN RESULTS

Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2-9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1-9.

CONCLUSIONS

High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival.

Tuberculosis in migrant populations. A systematic review of the qualitative literature

BACKGROUND

The re-emergence of tuberculosis (TB) in low-incidence countries and its disproportionate burden on immigrants is a public health concern posing specific social and ethical challenges. This review explores perceptions, knowledge, attitudes and treatment adherence behaviour relating to TB and their social implications as reported in the qualitative literature.

METHODS

Systematic review in four electronic databases. Findings from thirty selected studies extracted, tabulated, compared and synthesized.

FINDINGS

TB was attributed to many non-exclusive causes including air-born transmission of bacteria, genetics, malnutrition, excessive work, irresponsible lifestyles, casual contact with infected persons or objects; and exposure to low temperatures, dirt, stress and witchcraft. Perceived as curable but potentially lethal and highly contagious, there was confusion around a condition surrounded by fears. A range of economic, legislative, cultural, social and health system barriers could delay treatment seeking. Fears of deportation and having contacts traced could prevent individuals from seeking medical assistance. Once on treatment, family support and "the personal touch" of health providers emerged as key factors facilitating adherence. The concept of latent infection was difficult to comprehend and while TB screening was often seen as a socially responsible act, it could be perceived as discriminatory. Immigration and the infectiousness of TB mutually reinforced each another exacerbating stigma. This was further aggravated by indirect costs such as losing a job, being evicted by a landlord or not being able to attend school.

CONCLUSIONS

Understanding immigrants' views of TB and the obstacles that they face when accessing the health system and adhering to a treatment programme-taking into consideration their previous experiences at countries of origin as well as the social, economic and legislative context in which they live at host countries- has an important role and should be considered in the design, evaluation and adaptation of programmes.

Tuberculosis screening in immigrants from high-prevalence countries: interview first or chest radiograph first? A pro/con debate

Immigration from high tuberculosis (TB) prevalence countries has a substantial impact on the epidemiology of TB in receiving countries with low TB incidence. Cross-border migration offers an ideal opportunity for active case finding that will result in a lower caseload in the host country and a reduced spread of disease to both the indigenous and migrant populations. Screening strategies can start 'offshore', thereby indirectly assisting and empowering public health systems in the source countries, or be performed at ports of entry with or without long-term engagement of 'onshore' facilities and systems to provide either preventive therapy or surveillance for reactivation of latent TB. The chest radiograph seems to be playing a key role in this process, but questions remain regarding when, where and in whom radiographs are best done for optimal yield and cost-effectiveness, and with what other tests they might best be combined to further increase the usefulness of transborder TB control.

Cost-effectiveness of Quantiferon®-TB Gold-in-Tube versus tuberculin skin testing for contact screening and treatment of latent tuberculosis infection in Brazil

Background

Latent tuberculosis infection (LTBI) is a reservoir for new TB cases. Isoniazid preventive therapy (IPT) reduces the risk of active TB by as much as 90%, but LTBI screening has limitations. Unlike tuberculin skin testing (TST), interferon-gamma release assays are not affected by BCG vaccination, and have been reported to be cost-effective in low-burden countries. The goal of this study was to perform a cost-effectiveness analysis from the health system perspective, comparing three strategies for LTBI diagnosis in TB contacts: tuberculin skin testing (TST), QuantiFERON®-TB Gold-in-Tube (QFT-GIT) and TST confirmed by QFT-GIT if positive (TST/QFT-GIT) in Brazil, a middle-income, high-burden country with universal BCG coverage.

Methodology/Principal Findings

Costs for LTBI diagnosis and treatment of a hypothetical cohort of 1,000 adult immunocompetent close contacts were considered. The effectiveness measure employed was the number of averted TB cases in two years. Health system costs were US$ 105,096 for TST, US$ 121,054 for QFT-GIT and US$ 101,948 for TST/QFT-GIT; these strategies averted 6.56, 6.63 and 4.59 TB cases, respectively. The most cost-effective strategy was TST (US$ 16,021/averted case). The incremental cost-effectiveness ratio was US$ 227,977/averted TB case for QFT-GIT. TST/QFT-GIT was dominated.

Conclusions

Unlike previous studies, TST was the most cost-effective strategy for averting new TB cases in the short term. QFT-GIT would be more cost-effective if its costs could be reduced to US$ 26.95, considering a TST specificity of 59% and US$ 18 considering a more realistic TST specificity of 80%. Nevertheless, with TST, 207.4 additional people per 1,000 will be prescribed IPT compared with QFT.

Screening for TB in high school adolescents in a high burden setting in South Africa

Screening for tuberculosis (TB) disease is important for TB control and TB vaccine efficacy trials but this has not been evaluated in adolescents. We conducted a study to determine the prevalence of active TB and performance of specific screening tests for TB in adolescents in a high burden setting. Adolescents aged 12-18 years were recruited from high schools in a rural town in South Africa. Participants were screened for active TB using symptoms, household TB contact, positive interferon gamma release assay (IGRA) and positive tuberculin skin test (TST). Of 6363 adolescents recruited, 21 were newly diagnosed with TB of whom 19 were culture positive. After exclusions, the derived prevalence of smear positive TB was 16/5682 = 3/1000 (95% confidence interval (CI) 1-4/1000). The sensitivity of TST and IGRA for active TB were 85% (95% CI 62-100%) and 94% (95% CI 79-100%) respectively. None of the methods alone or in combination had positive predictive values greater than 2%. The screening tools evaluated in this study may not be practical for routine use owing to low positive predictive values but may be useful in TB vaccine clinical trials.

What is the cost of diagnosis and management of drug resistant tuberculosis in South Africa?

BACKGROUND

Drug-resistant tuberculosis (DR-TB) is undermining TB control in South Africa. However, there are hardly any data about the cost of treating DR-TB in high burden settings despite such information being quintessential for the rational planning and allocation of resources by policy-makers, and to inform future cost-effectiveness analyses.

METHODOLOGY

We analysed the comparative 2011 United States dollar ($) cost of diagnosis and treatment of drug sensitive TB (DS-TB), MDR-TB and XDR-TB, based on National South African TB guidelines, from the perspective of the National TB Program using published clinical outcome data.

PRINCIPAL FINDINGS

Assuming adherence to national DR-TB management guidelines, the per patient cost of XDR-TB was $26,392, four times greater than MDR-TB ($6772), and 103 times greater than drug-sensitive TB ($257). Despite DR-TB comprising only 2.2% of the case burden, it consumed ~32% of the total estimated 2011 national TB budget of US $218 million. 45% and 25% of the DR-TB costs were attributed to anti-TB drugs and hospitalization, respectively. XDR-TB consumed 28% of the total DR-TB diagnosis and treatment costs. Laboratory testing and anti-TB drugs comprised the majority (71%) of MDR-TB costs while hospitalization and anti-TB drug costs comprised the majority (92%) of XDR-TB costs. A decentralized XDR-TB treatment programme could potentially reduce costs by $6930 (26%) per case and reduce the total amount spent on DR-TB by ~7%.

CONCLUSION/SIGNIFICANCE

Although DR-TB forms a very small proportion of the total case burden it consumes a disproportionate and substantial amount of South Africa's total annual TB budget. These data inform rational resource allocation and selection of management strategies for DR-TB in high burden settings.

Influence of the 2009 financial crisis on detection of advanced pulmonary tuberculosis in Osaka city, Japan: a cross-sectional study

OBJECTIVE

To investigate the association between the economic recession and the detection of advanced cases of pulmonary tuberculosis in Osaka city from 2007 to 2009.

DESIGN

A repeated cross-sectional study.

SETTING

Osaka city has been the highest tuberculosis burden area in Japan. After the previous global financial crisis, the unemployment rate in Osaka prefecture has deteriorated from 5.3% in 2008 to 6.6% in 2009.

PARTICIPANTS

During the study period, 3406 pulmonary tuberculosis cases were enrolled: 2530 males and 876 females; 1546 elderly cases (65 years and above) and 1860 young cases (under 65 years); 417 homeless cases and 2989 non-homeless cases.

OUTCOME MEASURES

Patients' information included the sex, age, registry, health insurances, places of detection, sputum smear test results, patients' delay, doctors' delay and the grade of chest x-ray findings. They were statistically analysed between 2007 and 2008, two years before and just before the financial crisis, and between 2008 and 2009, just before and after the financial crisis.

RESULTS

The total numbers of pulmonary tuberculosis cases were 1172 in 2007, 1083 in 2008 and 1151 in 2009. In health examinations for non-homeless people, higher number of cases in 2009 were sputum smear positive, had respiratory symptoms and showed advanced disease in chest x-rays than those in 2008, with a longer patients' delay. On the contrary, in health examination for homeless people, fewer cases of advanced pulmonary tuberculosis were found in 2009 than in 2008, with a shorter patients' delay. In clinical examinations, there was no trend towards a difference between non-homeless and homeless people.

CONCLUSIONS

Although homeless people might be protected by public assistance, tuberculosis prevention and control need to be reinforced for the non-homeless population after the financial crisis.

Cost-effectiveness of different screening strategies (single or dual) for the diagnosis of tuberculosis infection in healthcare workers

OBJECTIVE

To evaluate the cost-effectiveness of a dual strategy of tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT-G) for screening of latent tuberculosis infection (LTBI) in healthcare workers (HCWs) and, as a secondary objective, to study relationships between TST results, QFT-G results, and sociodemographic factors.

DESIGN

Cross-sectional prospective study.

SETTING

University hospital in Madrid.

PARTICIPANTS

A total of 103 HCWs.

METHODS

QFT-G was requested for all positive TST results; QFT-G results were compared with TST results, and their relationships with sociodemographic factors were analyzed. A cost-effectiveness analysis was conducted for the dual strategy (TST/QFT-G) and for TST or QFT alone, taking into account the indication of and compliance with isoniazid, the risk of hepatotoxicity, and postexposure tuberculosis.

RESULTS

Of all HCWs studied, 42.3% showed a positive result by QFT-G, and 49.5% had received bacille Calmette-Guérin (BCG) vaccination; no significant association was detected between BCG and QFT-G results. Increased TST was linked to higher positive QFT-G values (TST of 5-9.9 mm, 27.6%; TST of 15 mm or more, 56.5%; P=.03). The probability of positive QFT-G results was 1.04 times higher for each year of age (odds ratio, 1.04 [95% confidence interval, 1.01-1.09]; P=.0257). The incremental cost per active TB case prevented was lower for TST/QFT-G than for the other strategies studied (€14,211 per 1,000 HCWs). The number of people treated for LTBI per case of active TB prevented (number needed to treat) for TST/QFT-G was lower than for TST alone (17.2 vs 95.3 and 88.7 with the 5- and 10-mm cutoff value, respectively) or QFT-G alone (69.6).

CONCLUSIONS

Dual strategy with TST/QFT-G is more cost-effective than TST or QFT-G alone for the diagnosis of LTBI in HCWs.

Tracing contacts of TB patients in Malaysia: costs and practicality

Tuberculin skin testing (TST) and chest X-ray are the conventional methods used for tracing suspected tuberculosis (TB) patients. The purpose of the study was to calculate the cost incurred by Penang General Hospital on performing one contact tracing procedure using an activity based costing approach. Contact tracing records (including the demographic profile of contacts and outcome of the contact tracing procedure) from March 2010 until February 2011 were retrospectively obtained from the TB contact tracing record book. The human resource cost was calculated by multiplying the mean time spent (in minutes) by employees doing a specific activity by their per-minute salaries. The costs of consumables, Purified Protein Derivative vials and clinical equipment were obtained from the procurement section of the Pharmacy and Radiology Departments. The cost of the building was calculated by multiplying the area of space used by the facility with the unit cost of the public building department. Straight-line deprecation with a discount rate of 3% was assumed for the calculation of equivalent annual costs for the building and machines. Out of 1024 contact tracing procedures, TST was positive (≥10 mm) in 38 suspects. However, chemoprophylaxis was started in none. Yield of contact tracing (active tuberculosis) was as low as 0.5%. The total unit cost of chest X-ray and TST was MYR 9.23 (2.90 USD) & MYR 11.80 (USD 3.70), respectively. The total cost incurred on a single contact tracing procedure was MYR 21.03 (USD 6.60). Our findings suggest that the yield of contact tracing was very low which may be attributed to an inappropriate prioritization process. TST may be replaced with more accurate and specific methods (interferon gamma release assay) in highly prioritized contacts; or TST-positive contacts should be administered 6H therapy (provided that the chest radiography excludes TB) in accordance with standard protocols. The unit cost of contact tracing can be significantly reduced if radiological examination is done only in TST or IRGA positive contacts.

Japan's national tuberculosis control strategies with economic considerations

We made a bibliographic search for Japanese and non-Japanese literature on tuberculosis control programs to study the current public health policies for tuberculosis control in Japan especially in regard to cost-effectiveness. Then, we compared the Japanese, strategies for tuberculosis control with those in other countries including the United States, and those recommended by World Health Organization (WHO). The current trend of tuberculosis incidence in the Japanese community demonstrates major differences from the situation that had prompted installation of tuberculosis control measures several decades ago. The tuberculosis control measures should be targeted to the elderly people (over 65 years old) because of the following three aspects. (1) A continuing decline of tuberculosis in the young Japanese population, particularly children who might attain benefits from BCG immunization; (2) The enhancement of the prevalence among the elderly people who are not covered by a uniform national surveillance strategy; (3) Cost-ineffectiveness of Mass Miniature Radiography (MMR) being used as a means to screen for tuberculosis. The cost-effectiveness issue must be considered more seriously, and the WHO recommendations especially in regard with the DOTS (directly-observed treatment, short course) strategy need to be incorporated more effectively into the national program since the incidence of drug resistant tuberculosis in Japan has been recently increasing. Finally, we propose to limit BCG immunization further and to discontinue annual MMR in the young population, and instead to develop effective strategies of both active and passive case finding in the elderly through public and community health services.

Community-based evaluation of immigrant tuberculosis screening using interferon γ release assays and tuberculin skin testing: observational study and economic analysis

BACKGROUND

UK tuberculosis (TB) notifications are rising due to disease in the immigrant population. National screening guidelines have been revised but cost-effectiveness analyses are hampered by the lack of data on the comparative performance of tuberculin skin tests (TSTs) and interferon γ release assays (IGRAs) in immigrants.

METHODS

Three-way evaluation of TSTs and two IGRAs (QuantiFERON Gold in-tube (QFN-GIT) and T-SPOT.TB) in immigrants aged ≥16 years to quantify test positivity, concordance and factors associated with positivity. Yields were computed at different incidence thresholds and the relative cost-effectiveness of screening was estimated using different latent TB infection (LTBI) screening modalities at varying incidence thresholds with or without port-of-arrival chest x-ray (CXR).

RESULTS

231 immigrants were included; median age 29 (IQR 24-37). TSTs were accepted by 80.9%, read in 93.5% and 30.3% were positive - QFN-GIT and T-SPOT.TB positive in 16.6% and 22.5% respectively. Positive TSTs, QFN-GIT and T-SPOT.TB were independently associated with increasing TB incidence in immigrants' countries of origin (p=0.007, 0.007, 0.037 respectively). Implementing current guidance (threshold 40/100 000 per year) would identify 98-100% of LTBIs (depending on test) but entail testing 97-99% of the cohort; screening at 150/100 000 per year would identify 49-71% of LTBIs but only entail screening half the cohort. The two most cost-effective screening strategies were no port-of-entry chest radiography and screen with single-step QFN-GIT at 250/100 000 per year (incremental cost-effectiveness ratio (ICER)) £21 565.3/case averted); and no port-of-entry CXR and screen with single-step QFN-GIT at 150/100 000 per year (averted additional 7.8 TB cases; ICER £31 867.1/case averted).

CONCLUSIONS

UK immigrant screening could cost-effectively and safely eliminate mandatory CXR on arrival by emphasising systematic screening for LTBI with single-step IGRA. Intermediate incidence thresholds balance the need to identify as many imported LTBIs as possible against limited service capacity.

Tuberculosis screening in migrant reception centers: results of a 2009 Italian survey

BACKGROUND

Tuberculosis (TB) is a social disease that is common in immigrants who are forced to live in difficult circumstances. In Italy, the guidelines for preventing TB include X-ray screening and application of the Mantoux test for migrants from high-TB-endemic countries as soon as possible after admission to Italy. This article describes a field survey conducted in the reception center for asylum seekers in Bari Palese in southern Italy following the death of a center resident from pulmonary TB.

METHODS

A Mantoux screening test, followed by chest X-ray, was carried out in March 2009 on 982 immigrants, representing 97.5% of the residents of the center.

RESULTS

A positive Mantoux test result was seen in 60.7% of the residents screened. The chest X-rays were performed on 92.9% of cuti-positive patients and on cuti-negative patients who were recent contacts of the deceased TB case and/or with symptoms suspicious for TB. Eight residents were diagnosed with active TB (0.8% of residents), and 117 residents (11.9%) had TB sequelae. In our survey, the Mantoux test demonstrated 88% sensitivity, 17% specificity, and a positive predictive value of 1% for active TB.

CONCLUSION

The survey results suggest that residents in asylum centers are a special type of immigrant. Specific risk factors, such as overcrowding, may expose these residents to a greater risk for infectious diseases.

Preemployment screening for tuberculosis in a large health care setting: comparison of the tuberculin skin test and a whole-blood interferon-γ release assay

OBJECTIVE

Determine the performance of an interferon-γ release assay in a health care occupational surveillance program.

METHODS

From January 11, 2005, through January 31, 2006, all new employees (n = 652) undergoing standard, preemployment evaluation at Mayo Clinic, Rochester, Minnesota were evaluated for tuberculosis using a standard process of symptom screening combined with tuberculin skin test (TST) and QuantiFERON-TB Gold test (QFT-G).

RESULTS

Comparing the results of QFT-G directly to TST, QFT-G showed an overall agreement of 92.5%.

CONCLUSIONS

False-positive TST were the most significant issue affecting agreement, and in a low-tuberculosis prevalence population, the need for an effective strategy offering low false-positive results may be best met by combining the TST with QFT-G.

Screening of immigrants in the UK for imported latent tuberculosis: a multicentre cohort study and cost-effectiveness analysis

Background

Continuing rises in tuberculosis notifications in the UK are attributable to cases in foreign-born immigrants. National guidance for immigrant screening is hampered by a lack of data about the prevalence of, and risk factors for, latent tuberculosis infection in immigrants. We aimed to determine the prevalence of latent infection in immigrants to the UK to define which groups should be screened and to quantify cost-effectiveness.

Methods

In our multicentre cohort study and cost-effectiveness analysis we analysed demographic and test results from three centres in the UK (from 2008 to 2010) that used interferon-γ release-assay (IGRA) to screen immigrants aged 35 years or younger for latent tuberculosis infection. We assessed factors associated with latent infection by use of logistic regression and calculated the yields and cost-effectiveness of screening at different levels of tuberculosis incidence in immigrants' countries of origin with a decision analysis model.

Findings

Results for IGRA-based screening were positive in 245 of 1229 immigrants (20%), negative in 982 (80%), and indeterminate in two (0·2%). Positive results were independently associated with increases in tuberculosis incidence in immigrants' countries of origin (p=0·0006), male sex (p=0·046), and age (p<0·0001). National policy thus far would fail to detect 71% of individuals with latent infection. The two most cost-effective strategies were to screen individuals from countries with a tuberculosis incidence of more than 250 cases per 100 000 (incremental cost-effectiveness ratio [ICER] was £17 956 [£1=US$1·60] per prevented case of tuberculosis) and at more than 150 cases per 100 000 (including immigrants from the Indian subcontinent), which identified 92% of infected immigrants and prevented an additional 29 cases at an ICER of £20 819 per additional case averted.

Interpretation

Screening for latent infection can be implemented cost-effectively at a level of incidence that identifies most immigrants with latent tuberculosis, thereby preventing substantial numbers of future cases of active tuberculosis.

Funding

Medical Research Council and Wellcome Trust.

Health service delivery for newly arrived refugee children: a framework for good practice

AIM

To propose a framework for good practice to promote improved access, equity and quality of care in service delivery for newly arrived refugee children.

METHODS

Development of a framework based on national and international literature and current service models in Australian paediatric refugee health.

RESULTS

Ten elements of a framework for good practice were identified: comprehensive health screening; coordination of initial and ongoing health care; integration of physical, developmental and psychological health care; consumer participation; culturally and linguistically appropriate service provision; intersectoral collaboration; accessible and affordable services and treatments; data collection and evaluation to inform evidence-based practice; capacity building and sustainability; and advocacy.

CONCLUSIONS

High-quality care can be achieved through a range of service models. The elements identified provide a framework for evaluating current services and for planning future service development. The framework for good practice can be applied to facilitate improvements in refugee health care and to reduce the gap between health needs and currently available services.

Different screening strategies (single or dual) for the diagnosis of suspected latent tuberculosis: a cost effectiveness analysis

BACKGROUND

Previous health economic studies recommend either a dual screening strategy [tuberculin skin test (TST) followed by interferon-gamma-release assay (IGRA)] or a single one [IGRA only] for latent tuberculosis infection (LTBI), the former largely based on claims that it is more cost-effective. We sought to examine that conclusion through the use of a model that accounts for the additional costs of adverse drug reactions and directly compares two commercially available versions of the IGRA: the Quantiferon-TB-Gold-In-Tube (QFT-GIT) and T-SPOT.TB.

METHODS

A LTBI screening model directed at screening contacts was used to perform a cost-effectiveness analysis, from a UK healthcare perspective, taking into account the risk of isoniazid-related hepatotoxicity and post-exposure TB (2 years post contact) using the TST, QFT-GIT and T-SPOT.TB IGRAs.

RESULTS

Examining costs alone, the TST/IGRA dual screening strategies (TST/T-SPOT.TB and TST/QFT-GIT; 162,387 pounds and 157,048 pounds per 1000 contacts, respectively) cost less than their single strategy counterparts (T-SPOT.TB and QFT-GIT; 203,983 pounds and 202,921 pounds per 1000 contacts) which have higher IGRA test costs and greater numbers of persons undergoing LTBI treatment. However, IGRA alone strategies direct healthcare interventions and costs more accurately to those that are truly infected.Subsequently, less contacts need to be treated to prevent an active case of TB (T-SPOT.TB and QFT-GIT; 61.7 and 69.7 contacts) in IGRA alone strategies. IGRA single strategies also prevent more cases of post-exposure TB. However, this greater effectiveness does not outweigh the lower incremental costs associated with the dual strategies. Consequently, when these costs are combined with effectiveness, the IGRA dual strategies are more cost-effective than their single strategy counterparts. Comparing between the IGRAs, T-SPOT.TB-based strategies (single and dual; 39,712 pounds and 37,206 pounds per active TB case prevented, respectively) were more cost-effective than the QFT-GIT-based strategies (single and dual; 42,051 pounds and 37,699 pounds per active TB case prevented, respectively). Using the TST alone was the least cost-effective (47,840 pounds per active TB case prevented). Cost effectiveness values were sensitive to changes in LTBI prevalence, IGRA test sensitivities/specificities and IGRA test costs.

CONCLUSION

A dual strategy is more cost effective than a single strategy but this conclusion is sensitive to screening test assumptions and LTBI prevalence.

Referrals for positive tuberculin tests in new health care workers and students: a retrospective cohort study

BACKGROUND

Documentation of test results for latent tuberculosis (TB) infection is important for health care workers and students before they begin work. A negative result provides a baseline for comparison with future tests. A positive result affords a potential opportunity for treatment of latent infection when appropriate. We sought to evaluate the yield of the referral process for positive baseline tuberculin tests, among persons beginning health care work or studies.

METHODS

Retrospective cohort study. We reviewed the charts of all new health care students and workers referred to the Montreal Chest Institute in 2006 for positive baseline tuberculin skin tests (> or =10 mm). Health care workers and students evaluated for reasons other than positive baseline test results were excluded.

RESULTS

630 health care students and workers were evaluated. 546 (87%) were foreign-born, and 443 (70%) reported previous Bacille Calmette-Guérin (BCG) vaccination. 420 (67%) were discharged after their first evaluation without further treatment. 210 (33%) were recommended treatment for latent TB infection, of whom 165 (79%) began it; of these, 115 (70%) completed adequate treatment with isoniazid or rifampin. Treatment discontinuation or interruption occurred in a third of treated subjects, and most often reflected loss to follow-up, or abdominal discomfort. No worker or student had active TB.

CONCLUSIONS

Only a small proportion of health care workers and students with positive baseline tuberculin tests were eligible for, and completed treatment for latent TB infection. We discuss recommendations for improving the referral process, so as to better target workers and students who require specialist evaluation and treatment for latent TB infection. Treatment adherence also needs improvement.

Multidrug-resistant tuberculosis in Victoria: a 10-year review

OBJECTIVE

To describe demographic and clinical characteristics of patients residing in Victoria who were diagnosed with multidrug-resistant tuberculosis (MDR-TB) during the period 1 January 1998 to 31 December 2007.

DESIGN, SETTING AND PATIENTS

Retrospective review of Victorian Department of Health data on laboratory-confirmed cases of MDR-TB for the period 1998-2007.

MAIN OUTCOME MEASURES

Age, sex, country of birth, time between arrival in Australia and notification of TB, residency status, site of disease, and treatment period and outcome.

RESULTS

From 1998 to 2007, 31 patients who resided in Victoria were diagnosed with MDR-TB. The median age of patients was 27 years, most patients were born overseas, and more than half were full-time students. The median time between arrival in Australia and notification of TB was 2 years, and 24 patients were notified to the Department within 5 years of arrival. Twenty patients had pulmonary disease; in 12 of these patients, sputum was smear-positive for acid-fast bacilli. The median treatment period for patients who completed treatment was 22 months.

CONCLUSIONS

The number of patients diagnosed with MDR-TB per year increased during the period 1998-2007. If sustained, this increase will have important implications for public health policy and planning.

Direct and indirect costs of tuberculosis among immigrant patients in the Netherlands

BACKGROUND

In low tuberculosis (TB) incidence countries TB affects mostly immigrants in the productive age group. Little empirical information is available about direct and indirect TB-related costs that patients face in these high-income countries. We assessed the direct and indirect costs of immigrants with TB in the Netherlands.

METHODS

A cross-sectional survey at 14 municipal health services and 2 specialized TB hospitals was conducted. Interviews were administered to first or second generation immigrants, 18 years or older, with pulmonary or extrapulmonary TB, who were on treatment for 1-6 months. Out of pocket expenditures and time loss, related to TB, was assessed for different phases of the current TB illness.

RESULTS

In total 60 patients were interviewed. Average direct costs spent by households with a TB patient amounted euro353. Most costs were spent when being hospitalized. Time loss (mean 81 days) was mainly due to hospitalization (19 days) and additional work days lost (60 days), and corresponded with a cost estimation of euro2603.

CONCLUSION

Even in a country with a good health insurance system that covers medication and consultation costs, patients do have substantial extra expenditures. Furthermore, our patients lost on average 2.7 months of productive days. TB patients are economically vulnerable.

Costs for tuberculosis care in Canada

OBJECTIVES

We have estimated tuberculosis (TB)-related expenditures by governments and other third parties in Canada in 2004, in order to compare spending on different activities, by various jurisdictions, and in different regions.

METHODS

To ascertain health system costs (including public health costs), a self-administered questionnaire was completed by all federal, provincial, and territorial health departments and laboratories involved in TB activities and a sample of local health departments. Hospitalization information was obtained from the Canadian Institute for Health Information, while costs for care were derived from published literature. Costs borne by patients and families were not included. All costs were ascertained for 2004 and expressed in Canadian dollars.

RESULTS

In 2004, total TB-related expenditures in Canada were $74 million, equivalent to $47,290 for every active TB case diagnosed in that year. Research accounted for $4.5 million (or 6% of the total). Non-research-related federal spending accounted for $16.3 million (22%) and provincial/territorial expenditures accounted for $53.1 million (72%). Active tuberculosis accounted for $31 million or 59% of provincial/territorial expenditures. There were substantial regional differences in TB-related expenditures; the highest expenditures were in the Northern Territories ($72,441 per active TB case), followed by the four Western provinces ($35,914), and lowest in the Atlantic provinces ($28,259).

CONCLUSIONS

Total TB-related expenditures in Canada in 2004 were considerable, of which almost 60% were for curative services and only 40% for prevention and control activities. Regional differences likely reflect differences in accessibility of the populations to health care services, and greater interventions in communities with ongoing TB transmission.

Health state utilities in latent and active tuberculosis

BACKGROUND

Tuberculosis (TB) remains a major public health threat worldwide. Numerous cost-effectiveness analyses of TB screening and treatment strategies have been recently published, but none have utilized quality-adjusted life-years as recommended because of the lack of utilities for TB health states.

OBJECTIVE

To characterize and compare utility scores from either active TB or latent TB infection (LTBI) participants.

METHODS

Consenting patients attending a population-based screening and treatment clinic were administered the Short Form 36 (SF-36), the Health Utilities Index 2/3 (HUI2/3), and a general health visual analog scale (VAS) along with demographic questions. SF-36 scores were converted to Short Form 6D (SF-6D) utility scores using an accepted algorithm. Utility results were compared across scales, and construct validity was assessed.

RESULTS

A total of 162 TB patients (78 LTBI and 84 active TB) with available SF-36 and all four utility scores (Health Utilities Index 2, Health Utilities Index 3, SF-6D and VAS) were included in the analysis. Those with active TB had significantly lower SF-36 and utility scores than those with LTBI. Although all appeared to exhibit construct validity, the HUI2/3 and the VAS appeared to have significant ceiling effects, whereas the SF-6D had significant floor effects.

CONCLUSIONS

Health state utility values for active TB and LTBI have been determined using different instruments. The three measures did not generate identical utility scores. The HUI2/3 was limited by ceiling effects, whereas the SF-6D appeared to display floor effects.

Cost-effectiveness of LTBI treatment for TB contacts in British Columbia

BACKGROUND

Contacts of patients with active tuberculosis ("TB contacts") with a tuberculin skin test (TST) size > or = 5 mm are currently recommended treatment for latent TB infection (LTBI). Knowing the cost-effectiveness of LTBI therapy for specific TB contact subpopulations may improve the use of limited resources by reducing the treatment of persons at low TB risk.

OBJECTIVE

To evaluate the cost-effectiveness of LTBI therapy for different TB contact populations defined by important risk factors, and to propose an optimal policy based on different recommendation for each subgroup of contacts.

METHODS

A 6-year Markov decision analytic model simulating the quality-adjusted life years (QALYs), number of active TB cases prevented, and costs for hypothetical cohorts of Canadian TB contacts defined by TST size, age group (< 10 y/o or above), ethnicity, closeness of contact, and Bacillus Calmette-Guérin (BCG) vaccination status.

RESULTS

For the majority of subgroups, the current policy of preventive therapy in those with positive TST was the most cost-effective. Nevertheless, our analysis determined that LTBI treatment is not cost-effective in nonhousehold Canadian-born (nonaboriginal) or foreign-born contacts age > or = 10 y/o. On the other hand, empirical treatment without screening of all non-BCG-vaccinated household contacts age < 10 y/o appeared cost-effective. Such an optimal approach would result in an incremental net monetary benefit of $25 for each contact investigated for a willingness-to-pay of $50,000/QALY. Results were robust to several alternative assumptions considered in sensitivity analyses.

CONCLUSIONS

The current practice of LTBI treatment for TB contacts with a TST size > or = 5 mm is cost-effective. A customized approach based on excluding low risk groups from screening and providing treatment to high risk contacts without screening could improve the performance of the program.

Tuberculosis screening of travelers to higher-incidence countries: a cost-effectiveness analysis

Background

Travelers to countries with high tuberculosis incidence can acquire infection during travel. We sought to compare four screening interventions for travelers from low-incidence countries, who visit countries with varying tuberculosis incidence.

Methods

Decision analysis model: We considered hypothetical cohorts of 1,000 travelers, 21 years old, visiting Mexico, the Dominican Republic, or Haiti for three months. Travelers departed from and returned to the United States or Canada; they were born in the United States, Canada, or the destination countries. The time horizon was 20 years, with 3% annual discounting of future costs and outcomes. The analysis was conducted from the health care system perspective. Screening involved tuberculin skin testing (post-travel in three strategies, with baseline pre-travel tests in two), or chest radiography post-travel (one strategy). Returning travelers with tuberculin conversion (one strategy) or other evidence of latent tuberculosis (three strategies) were offered treatment. The main outcome was cost (in 2005 US dollars) per tuberculosis case prevented.

Results

For all travelers, a single post-trip tuberculin test was most cost-effective. The associated cost estimate per case prevented ranged from $21,406 for Haitian-born travelers to Haiti, to $161,196 for US-born travelers to Mexico. In all sensitivity analyses, the single post-trip tuberculin test remained most cost-effective. For US-born travelers to Haiti, this strategy was associated with cost savings for trips over 22 months. Screening was more cost-effective with increasing trip duration and infection risk, and less so with poorer treatment adherence.

Conclusion

A single post-trip tuberculin skin test was the most cost-effective strategy considered, for travelers from the United States or Canada. The analysis did not evaluate the use of interferon-gamma release assays, which would be most relevant for travelers who received BCG vaccination after infancy, as in many European countries. Screening decisions should reflect duration of travel, tuberculosis incidence, and commitment to treat latent infection.

Tuberculosis among foreign-born persons in Taiwan, 2002-2005

BACKGROUND/PURPOSE

The foreign-born population has been growing in Taiwan. Most foreign-born persons come from countries with a high burden of tuberculosis (TB). Monitoring the trend and characteristics of TB in this population is essential for TB control in Taiwan.

METHODS

Information about foreign-born persons residing in Taiwan and data of all foreign-born TB cases notified during 2002-2005 were obtained from the national authorities and analyzed.

RESULTS

A total of 2,444 foreign-born TB cases were notified during 2002-2005, which accounted for 3.6% of all notified TB cases during that period in Taiwan. The proportion of foreign-born TB cases was constant, without any significant yearly variation. The average annual TB notification rate in the foreign-born population was higher than that in the Taiwan-born population (94.0/100,000 vs. 72.0/100,000). There were significant differences in age, sex and regional distribution between foreign-born and Taiwan-born TB cases (p < 0.001). Foreign-born cases were predominantly female (65.4%) and aged 25-44 years (70.9%), whereas the majority of cases among the Taiwan-born population were male (69.4%) and aged > or = 65 years (49.6%). Most foreign-born TB patients (62.7%) lived in northern Taiwan but only about one-third (36.1%) of Taiwan-born TB cases were notified from that region. Among foreign-born TB cases whose original countries were recorded, the majority came from Mainland China and Vietnam, which accounted for 73.0% of all cases, followed by the Philippines (7.4%), Thailand (7.3%) and Indonesia (6.0%).

CONCLUSION

Foreign-born TB patients have different profiles and a higher case rate compared to Taiwan-born patients. Monitoring the epidemiologic trend of TB among foreign-born persons, especially those who come from high TB-burden countries, is essential in the fight against TB in Taiwan.

Guía de práctica clínica de la Sociedad Andaluza de Enfermedades Infecciosas (SAEI) sobre el tratamiento de la tuberculosis

The therapeutic scheme for initial pulmonary tuberculosis recommended by the SAEI is as follows: Initial phase, isoniazid, rifampin and pyrazinamide given daily for 2 months. In HIV(+) patients and immigrants from areas with a rate of primary resistance to isoniazid > 4%, ethambutol should be added until susceptibility studies are available. Second phase (continuation phase): rifampin and isoniazid, given daily or intermittently for 4 months in the general population. HIV(+) patients (< or = 200 CD4) and culture-positive patients after 2 months of treatment should receive a 7-month continuation phase. A 6-month regimen is recommended for extrapulmonary tuberculosis, with the exception of tuberculous meningitis, which should be treated for a minimum of 12 months and bone/joint tuberculosis, treated for a minimum of 9 months. Treatment regimens for multidrug resistant tuberculosis are based on expert opinion. These would include a combination of still-useful first-line drugs, injectable agents, and alternative agents, such as quinolones. Patients who present a special risk of transmitting the disease or of non-adherence should be treated with directly observed therapy.

Prevalence of abnormal radiological findings in health care workers with latent tuberculosis infection and correlations with T cell immune response

Background

More than half of all health care workers (HCWs) in high TB-incidence, low and middle income countries are latently infected with tuberculosis (TB). We determined radiological lesions in a cohort of HCWs with latent TB infection (LTBI) in India, and determined their association with demographic, occupational and T-cell immune response variables.

Methodology

We obtained chest radiographs of HCWs who had undergone tuberculin skin test (TST) and QuantiFERON-TB Gold In Tube (QFT), an interferon-γ release assay, in a previous cross-sectional study, and were diagnosed to have LTBI because they were positive by either TST or QFT, but had no evidence of clinical disease. Two observers independently interpreted these radiographs using a standardized data form and any discordance between them resolved by a third observer. The radiological diagnostic categories (normal, suggestive of inactive TB, and suggestive of active TB) were compared with results of TST, QFT assay, demographic, and occupational covariates.

Results

A total of 330 HCWs with positive TST or QFT underwent standard chest radiography. Of these 330, 113 radiographs (34.2%) were finally classified as normal, 206 (62.4%) had lesions suggestive of inactive TB, and 11 (3.4%) had features suggestive of active TB. The mean TST indurations and interferon-γ levels in the HCWs in these three categories were not significantly different. None of the demographic or occupational covariates was associated with prevalence of inactive TB lesions on chest radiography.

Conclusion/Significance

In a high TB incidence setting, nearly two-thirds of HCWs with latent TB infection had abnormal radiographic findings, and these findings had no clear correlation with T cell immune responses. Further studies are needed to verify these findings and to identify the causes and prognosis of radiologic abnormalities in health care workers.

Impact of immigration on the molecular epidemiology of Mycobacterium tuberculosis in a low-incidence country

RATIONALE

Programs to prevent the incidence rate of tuberculosis (TB) from increasing in many low-incidence countries are challenged by international travel and immigration from high-burden countries.

OBJECTIVES

The current study aimed to determine the effect of such immigration on the genetic diversity of Mycobacterium tuberculosis isolates in an entire nation's population during 1994-2005.

METHODS

A total of 3,131 patients were notified with TB during the 12-year period. Of these, 2,284 (73%) had TB verified by culture, and isolates from 2,173 (96%) of these were analyzed by IS6110 restriction fragment length polymorphism.

MEASUREMENTS AND MAIN RESULTS

Only 31% of the included strains were isolated from nonimmigrants, the remaining 69% were isolated from immigrants. Although the incidence increased throughout the period, the genetic diversity remained high. A total of 135 clusters were identified; the percentage of recent disease was reduced among nonimmigrants, and remained stable among the immigrants during the study period. Although 69% of the isolates originated from immigrants from high-incidence countries, the established TB control program in the receiving country was adequate for the prevention of disease transmission. On average per year, only 2 nonimmigrants and 13 immigrants developed disease as a result of infection within the country by imported M. tuberculosis.

CONCLUSIONS

Twelve years of M. tuberculosis importation as a result of immigration from high-incidence countries had little influence on the transmission of this pathogen in the receiving low-incidence country. To prevent future increase of transmission of TB, the current control strategies of low-incidence countries are adequate but must be maintained.

Tuberculosis screening of asylum seekers: 1 years' experience at the Dover Induction Centres

OBJECTIVES

To describe the uptake and outcomes of a service for tuberculosis screening of asylum seekers.

STUDY DESIGN

Descriptive study.

METHODS

A tuberculosis screening service was established at the Dover Induction Centres for all asylum seekers entering the UK through ports in Kent. This study describes the uptake and completion of tuberculosis screening, the results of tuberculin skin testing and follow-up, and the cost of the service during its first year.

RESULTS

In 1 year, 8258 asylum seekers were screened: 94% of 8799 who were eligible. A total of 2.2% of those with completed screens were positive (on the basis of symptoms requiring further investigation or positive Heaf reaction). Eleven cases of active respiratory disease were diagnosed on the basis of symptoms, Heaf reaction plus chest X-ray, or both; three were confirmed microbiologically. One-quarter of Heaf tests were not read because of the rapid dispersal of asylum seekers. The follow-up of those requiring further investigations at their destinations was largely unknown. The service cost was 350,000 pounds.

CONCLUSIONS

Induction centre tuberculosis screening services for asylum seekers can achieve a high uptake, but their cost-effectiveness is questionable, particularly where the yield of active disease is low. Tuberculin skin testing is not an ideal screening procedure in this setting because it may be uncompleted and the benefit of detecting latent infections is uncertain.