Modeling the Cost-Effectiveness of Latent Tuberculosis Screening and Treatment Strategies in Recent Migrants to a Low-Incidence Setting

Many tuberculosis (TB) cases in low-incidence settings are attributed to reactivation of latent TB infection (LTBI) acquired overseas. We assessed the cost-effectiveness of community-based LTBI screening and treatment strategies in recent migrants to a low-incidence setting (Australia). A decision-analytical Markov model was developed that cycled 1 migrant cohort (≥11-year-olds) annually over a lifetime from 2020. Postmigration/onshore and offshore (screening during visa application) strategies were compared with existing policy (chest x-ray during visa application). Outcomes included TB cases averted and discounted cost per quality-adjusted life-year (QALY) gained from a health-sector perspective. Most recent migrants are young adults and cost-effectiveness is limited by their relatively low LTBI prevalence, low TB mortality risks, and high emigration probability. Onshore strategies cost at least $203,188 (Australian) per QALY gained, preventing approximately 2.3%-7.0% of TB cases in the cohort. Offshore strategies (screening costs incurred by migrants) cost at least $13,907 per QALY gained, preventing 5.5%-16.9% of cases. Findings were most sensitive to the LTBI treatment quality-of-life decrement (further to severe adverse events); with a minimal decrement, all strategies caused more ill health than they prevented. Additional LTBI strategies in recent migrants could only marginally contribute to TB elimination and are unlikely to be cost-effective unless screening costs are borne by migrants and potential LTBI treatment quality-of-life decrements are ignored.

A situational analysis of latent tuberculosis infection among incarcerated population in Japan

BACKGROUND

The World Health Organization recommends that systematic testing and screening of latent tuberculosis infection (LTBI) among the incarcerated population "should be considered", though based on evidence of either low or very low quality. However, in Japan, a TB middle-burden country, systematic screening for LTBI in correctional facilities is currently not conducted. As part of a larger study to determine the cost-effectiveness of LTBI screening in correctional facilities in Japan, this study was conducted to determine the situation of LTBI, including treatment outcome, among the incarcerated population in Japan, and provide the essential data for cost-effectiveness analysis.

METHOD

A cross-sectional study was conducted between 2017 and 2018 with public health centers which have one or more correctional facilities under their jurisdiction. Questionnaire surveys were sent to collect information on their policy of managing LTBI patients notified from correctional facilities, including whether or not there was a standardized procedure for initiating LTBI treatment, and also to collect sociodemographic information and treatment outcome of LTBI patients who were notified from the respective correctional facilities in 2015 and 2016.

RESULTS

The survey was sent to a total of 163 public health centers, out of which 133 (81.6%) responded. 8 of the 133 public health centers actively guided the correctional facilities regarding LTBI treatment initiation through a standardized procedure, while 115 either had not established such procedure or were unaware of how LTBI treatment was being initiated in the correctional facilities. A total of 91 LTBI patients were notified from the correctional facilities in 2015 and 2016, and the information of 89 were available for analysis. 82 were males, and 83 were Japan-born. Treatment outcome was known for 88 patients, of which 70 had completed treatment. Of the 18 who did not complete the treatment, 15 had been lost to follow-up upon release from the facilities. Among those who had been released whilst on treatment, the proportion of those who completed the treatment was higher in those patients who received pre-release visit by a public health nurse, than those who did not.

CONCLUSIONS

LTBI treatment was often being initiated without consideration for the patients' prison term. The treatment completion rate within jail was high, indicating the possibility that incarcerated population can benefit for LTBI treatment. On the other hand, the completion rate decreased significantly among those who had been released while still on treatment. In order to optimize the benefit, initiation of LTBI must carefully be considered upon the patient's prison term, as well as coordination among the relevant organizations to ensure continuity of care after release.

Burden of non-adherence to latent tuberculosis infection drug therapy and the potential cost-effectiveness of adherence interventions in Canada: a simulation study

OBJECTIVE

Pharmaceutical treatment of latent tuberculosis infection (LTBI) reduces the risk of progression to active tuberculosis (TB); however, poor adherence tempers the protective effect. We aimed to estimate the health burden of non-adherence, the maximum allowable cost of hypothetical new adherence interventions to be cost-effective and the potential value of existing adherence interventions for patients with low-risk LTBI in Canada.

DESIGN

A microsimulation model of LTBI progression over 25 years.

SETTING

General practice in Canada.

PARTICIPANTS

Individuals with LTBI who are initiating drug therapy.

INTERVENTIONS

A hypothetical intervention with a range of effectiveness was evaluated. Existing drug adherence interventions including peer support, two-way text messaging support, enhanced adherence counselling and adherence incentives were also evaluated.

PRIMARY AND SECONDARY OUTCOME MEASURES

Simulation outcomes included healthcare costs, TB incidence, TB deaths and quality-adjusted life years (QALYs). Base case results were interpreted against a willingness-to-pay threshold of $C50 000/QALY.

RESULTS

Compared with current adherence levels, full adherence to LTBI drug therapy could reduce new TB cases from 90.3 cases per 100 000 person-years to 35.9 cases per 100 000 person-years and reduce TB-related deaths from 7.9 deaths per 100 000 person-years to 3.1 deaths per 100 000 person-years. An intervention that increases relative adherence by 40% would bring the population near full adherence to drug therapy and could have a maximum allowable annual cost of approximately $C450 per person to be cost-effective. Based on estimates of effect sizes and costs of existing adherence interventions, we found that they yielded between 900 and 2400 additional QALYs per million people, reduced TB deaths by 5%-25% and were likely to be cost-effective over 25 years.

CONCLUSION

Full adherence could reduce the number of future TB cases by nearly 60%, offsetting TB-related costs and health burden. Several existing interventions are could be cost-effective to help achieve this goal.

How much does tuberculosis cost? An Australian healthcare perspective analysis

Tuberculosis (TB) remains a disease of high morbidity in Australia, with implications for both public health and the individual. Cost analyses is relevant for programmatic evaluation of TB. There is minimal published TB cost data in the Australian setting. Patients with drug sensitive active pulmonary TB (DS-PTB) and latent TB (LTBI) were enrolled in a single tertiary referral centre to evaluate healthcare provider costs. The median cost of treating drug susceptible pulmonary TB in this case series was 11,538 AUD. Approximately 50% of total costs is derived from inpatient hospitalisation bed days. In comparison, the average cost of managing latent TB was 582 AUD per completed course. We find the median provider cost of our DS-PTB treatment group comparable to costs from other regions globally with similar economic profiles. A program designed to detect and treat LTBI to prevent subsequent disease may be cost effective in appropriately selected patients and warrants further study.

Immigrant screening for latent tuberculosis in Norway: a cost-effectiveness analysis

The incidence of tuberculosis (TB) disease has increased in Norway since the mid-1990s. Immigrants are screened, and some are treated, for latent TB infection (LTBI) to prevent TB disease (reactivation). In this study, we estimated the costs of both treating and screening for LTBI and TB disease, which has not been done previously in Norway. We developed a model to indicate the cost-effectiveness of four different screening algorithms for LTBI using avoided TB disease cases as the health outcome. Further, we calculated the expected value of perfect information (EVPI), and indicated areas of LTBI screening that could be changed to improve cost-effectiveness. The costs of treating LTBI and TB disease were estimated to be €1938 and €15,489 per case, respectively. The model evaluates four algorithms, and suggests three cost-effective algorithms depending on the cost-effectiveness threshold. Screening all immigrants with interferon-gamma release assays (IGRA) requires the highest threshold (€28,400), followed by the algorithms "IGRA on immigrants with risk factors" and "no LTBI screening." EVPI is approximately €5 per screened immigrant. The costs for a cohort of 20,000 immigrants followed through 10 years range from €12.2 million for the algorithm "screening and treatment for TB disease but no LTBI screening," to €14 million for "screening all immigrants for both TB disease and LTBI with IGRA." The results suggest that the cost of TB disease screening and treatment is the largest contributor to total costs, while LTBI screening and treatment costs are relatively small. Increasing the proportion of IGRA-positive immigrants who are treated decreases the costs per avoided case substantially.

Prevalence of Latent Tuberculosis among Health Care Workers in High Burden Countries: A Systematic Review and Meta-Analysis

Background

Tuberculosis is one of the leading causes of death worldwide. Twenty-two high burden countries contributed to the majority of worldwide tuberculosis cases in 2015. Health care workers are at high risk of acquiring tuberculosis through occupational exposure.

Objective

To estimate the prevalence of latent tuberculosis infection (LTBI) among health care workers in high burden countries.

Methods

Databases including MEDLINE (Ovid), EMBASE (Ovid), CINAHL (Ovid) and ISI Web of Science (Thompson-Reuters), and grey literature were searched for English language records on relevant medical subject headings (MeSH) terms of LTBI and health care providers. Literature was systematically reviewed using EPPI-Reviewer4 software. Prevalence and incidence of LTBI and 95% confidence intervals (CI) were reported. Pooled prevalence of LTBI and 95% CI were calculated using random-effects meta-analysis models and heterogeneity was assessed using I² statistics. Sub-group analysis was conducted to assess the cause of heterogeneity.

Results

A total of 990 records were identified. Of those, 18 studies from only 7 high burden countries representing 10,078 subjects were included. Tuberculin skin test results were available for 9,545 participants. The pooled prevalence of LTBI was 47% (95% CI 34% to 60%, I² = 99.6%). In subgroup analyses according to the country of the study, the pooled prevalence of LTBI was lowest in Brazil (37%) and highest in South Africa (64%). The pooled prevalence of LTBI among medical and nursing students was 26% (95% CI 6% to 46%, I² = 99.3%) while the prevalence among all types of health care workers was 57% (95% CI 44% to 70%, I² = 99.1%). Incidence of LTBI was available for health care workers in four countries. The cumulative incidence ranged from 2.8% in Brazilian medical students to 38% among all types of health care workers in South Africa.

Conclusion

The findings of this study suggest that there is a high burden of LTBI among health care workers in high burden countries. Adequate infection control measures are warranted to prevent and control transmission in health care settings.

Methods Used in Economic Evaluations of Tuberculin Skin Tests and Interferon Gamma Release Assays for the Screening of Latent Tuberculosis Infection: A Systematic Review

BACKGROUND

Latent tuberculosis infection (LTBI) provides a constant pool of new active tuberculosis cases; a third of the earth's population is estimated to be infected with LTBI.

OBJECTIVE

The objective of this systematic review was to assess the quality and summarize the available evidence from published economic evaluations reporting on the cost-effectiveness of tuberculin skin tests (TSTs) compared with interferon gamma release assays (IGRAs) for the screening of LTBI.

METHODS

An extensive systematic review of the published literature was conducted. A two-step process was adopted to identify relevant articles: information was extracted into evidence tables and then analyzed. The quality of the publications was assessed using a 10-item checklist specific for economic evaluations.

RESULTS

Twenty-eight studies were identified for inclusion in this review. Most of the studies found IGRAs to be more cost-effective than TSTs; however, the conclusions from the studies varied significantly. Most studies scored highly on the checklist although only one fulfilled all the stipulated criteria. A wide variety of methodological approaches were documented; identified differences included the type of economic evaluation and model, time horizon, perspective, and outcomes measures.

CONCLUSIONS

The lack of consistent methods across studies makes it difficult to draw any firm conclusions about the most cost-effective option between TSTs and IGRAs. This problem can be solved by improving the quality of economic evaluation studies in the field of LTBI screening, through adherence to quality checklists.

A Systematic Review of Studies Evaluating the Cost Utility of Screening High-Risk Populations for Latent Tuberculosis Infection

BACKGROUND

As tuberculosis screening trends to targeting high-risk populations, knowing the cost effectiveness of such screening is vital to decision makers.

OBJECTIVES

The purpose of this review was to compile cost-utility analyses evaluating latent tuberculosis infection (LTBI) screening in high-risk populations that used quality-adjusted life-years (QALYs) as their measure of effectiveness.

DATA SOURCES

A literature search of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Web of Knowledge, and PubMed was performed from database start to November 2014.

INCLUSION CRITERIA

Studies performed in populations at high risk of LTBI and subsequent reactivation that used the QALY as an effectiveness measure were included.

STUDY APPRAISAL AND SYNTHESIS

Quality was assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. Data extracted included tuberculin skin test (TST) and/or interferon-gamma release assay (IGRA) use, economic, screening, treatment, health state, and epidemiologic parameters. Data were summarized in regard to consistency in model parameters and the incremental cost-effectiveness ratio (ICER), with costs adjusted to 2013 US dollars.

RESULTS

Of 415 studies identified, ultimately eight studies were included in the review. Most took a societal perspective (n = 4), used lifetime time horizons (n = 6), and used Markov models (n = 8). Screening of adult immigrants was found to be cost effective with a TST in one study, but moderately cost effective with an IGRA in another study; screening immigrants arriving more than 5 years prior with an IGRA was moderately cost effective until 44 years of age (n = 1). Screening HIV-positive patients was highly cost effective with a TST (n = 1) and moderately cost effective with an IGRA (n = 1). Screening in those with renal diseases (n = 2) and diabetes (n = 1) was not cost effective.

LIMITATIONS

Very few studies used the QALY as their effectiveness measure. Parameter and study design inconsistencies limit the comparability of studies.

CONCLUSIONS

With validity issues in terms of parameters and assumptions, any conclusion should be interpreted with caution. Despite this, some cautionary recommendations emerged: screening HIV patients with a TST is highly cost effective, while screening adult immigrants with an IGRA is moderately cost effective.

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.

Current treatment options for latent tuberculosis infection

Treatment of latent tuberculosis infection (LTBI) is a key component in TB control strategies worldwide. However, as people with LTBI are neither symptomatic nor contagious, any screening decision should be weighed carefully against the potential benefit of preventing active disease in those who are known to be at higher risk and are willing to accept therapy for LTBI. This means that a targeted approach is desirable to maximize cost effectiveness and to guarantee patient adherence. We focus on LTBI treatment strategies in patient populations at increased risk of developing active TB, including candidates for treatment with tumor necrosis factor-α blockers. In the last 40 years, isoniazid (INH) has represented the keystone of LTBI therapy across the world. Although INH remains the first therapeutic option, alternative treatments that are effective and associated with increased adherence and economic savings are available. Current recommendations, toxicity, compliance, and cost issues are discussed in detail in this review. A balanced relationship between the patient and healthcare provider could increase adherence, while cost-saving treatment strategies with higher effectiveness, fewer side effects, and of shorter duration should be offered as preferred.

Cost for tuberculosis care in developed countries: which data for an economic evaluation?

Tuberculosis (TB) seems to be eradicated in developed countries. However, current migration flows and increasing use of immunosuppressive and biologic drugs for rheumatic diseases are increasing the risk of latent TB and TB onset for citizens of developed countries. Because little is known about the economic burden of TB in developed countries, we set out to describe the order and dimension of the costs of TB care in developed countries. A review of the literature indicated that the cost for anti-TB therapy is about $2000 US per patient. Costs of drugs associated with standard therapy for active TB [2HRZE/4HR, i.e., 2 months of isoniazid (H), rifampin (R), pyrazinamide (Z), and ethambutol (E), followed by 4 months of HR] are about $600. Standard therapy for latent TB care costs about $80 for 9H and $256 for 4R, respectively. However, these data are very limited because of the horizon of analysis and because data are strongly localized. It can be concluded that in developed countries, available data on TB care costs are insufficient for detailed analysis of the economic burden of TB.

Cost-effectiveness of a 12-dose regimen for treating latent tuberculous infection in the United States

SETTING

A large randomized controlled trial recently showed that for treating latent tuberculous infection (LTBI) in persons at high risk of progression to tuberculosis (TB) disease, a 12-dose regimen of weekly rifapentine plus isoniazid (3HP) administered as directly observed treatment (DOT) can be as effective as 9 months of daily self-administered isoniazid (9H).

OBJECTIVES

To assess the cost-effectiveness of 3HP compared to 9H.

DESIGN

A computational model was designed to simulate individuals with LTBI treated with 9H or 3HP. Costs and health outcomes were estimated to determine the incremental costs per active TB case prevented and per quality-adjusted life year (QALY) gained by 3HP compared to 9H.

RESULTS

Over a 20-year period, treatment of LTBI with 3HP rather than 9H resulted in 5.2 fewer cases of TB and 25 fewer lost QALYs per 1000 individuals treated. From the health system and societal perspectives, 3HP would cost respectively US$21,525 and $4294 more per TB case prevented, and respectively $4565 and $911 more per QALY gained.

CONCLUSIONS

3HP may be a cost-effective alternative to 9H, particularly if the cost of rifapentine decreases, the effectiveness of 3HP can be maintained without DOT, and 3HP treatment is limited to those with a high risk of progression to TB disease.

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.

Cost-effectiveness of rifampin for 4 months and isoniazid for 6 months in the treatment of tuberculosis infection

OBJECTIVES

To assess the cost-effectiveness ratio of rifampin for 4 months and isoniazid for 6 months in contacts with latent tuberculosis infection.

METHODS

The cost was the sum of the cost of treatment with isoniazid for 6 months or with rifampin for 4 months of all contacts plus the cost of treatment of cases of tuberculosis not avoided. The effectiveness was the number of cases of tuberculosis avoided with isoniazid for 6 months or with rifampin for 4 months. When the cost with one schedule was found to be cheaper than the other and a greater number of tuberculosis cases were avoided, this schedule was considered dominant. The efficacy adopted was 90% for rifampin for 4 months and 69% for isoniazid for 6 months. A sensitivity analysis was made for efficacies of rifampin for 4 months of 80%, 69%, 60% and 50%.

RESULTS

Of the 1002 patients studied, 863 were treated with isoniazid for 6 months and 139 with rifampin for 4 months The cost-effectiveness ratio with isoniazid for 6 month was € 19759.48/avoided case of tuberculosis and € 8736.86/avoided case of tuberculosis with rifampin for 4 months. Rifampin for 4 months was dominant. In the sensitivity analysis, rifampin for 4 months was dominant for efficacies from 60%.

CONCLUSIONS

Rifampin for 4 months was more cost-effective than isoniazid for 6 months.

How methodologic differences affect results of economic analyses: a systematic review of interferon gamma release assays for the diagnosis of LTBI

INTRODUCTION

Cost effectiveness analyses (CEA) can provide useful information on how to invest limited funds, however they are less useful if different analysis of the same intervention provide unclear or contradictory results. The objective of our study was to conduct a systematic review of methodologic aspects of CEA that evaluate Interferon Gamma Release Assays (IGRA) for the detection of Latent Tuberculosis Infection (LTBI), in order to understand how differences affect study results.

METHODS

A systematic review of studies was conducted with particular focus on study quality and the variability in inputs used in models used to assess cost-effectiveness. A common decision analysis model of the IGRA versus Tuberculin Skin Test (TST) screening strategy was developed and used to quantify the impact on predicted results of observed differences of model inputs taken from the studies identified.

RESULTS

Thirteen studies were ultimately included in the review. Several specific methodologic issues were identified across studies, including how study inputs were selected, inconsistencies in the costing approach, the utility of the QALY (Quality Adjusted Life Year) as the effectiveness outcome, and how authors choose to present and interpret study results. When the IGRA versus TST test strategies were compared using our common decision analysis model predicted effectiveness largely overlapped.

IMPLICATIONS

Many methodologic issues that contribute to inconsistent results and reduced study quality were identified in studies that assessed the cost-effectiveness of the IGRA test. More specific and relevant guidelines are needed in order to help authors standardize modelling approaches, inputs, assumptions and how results are presented and interpreted.

[Latent M. tuberculosis infection, update 2011]

It is estimated that one third of the world population is latently infected by Mycobacterium tuberculosis and thus at risk of reactivation. Latent tuberculosis (TB) impact in Switzerland is often overlooked. Diagnosis and prophylaxis are insufficiently undertaken, especially for people at higher risk of reactivation due to immunosuppression. Interferon-gamma release assays replace tuberculosis skin tests for diagnosis of latent infection in adults. It is still recommended to treat prophylactically a case of latent TB infection with 9 months of isoniazid; however therapy with rifampicin for 4 months, currently an alternative option, is linked to improved adherence and favorable cost-benefit ratio.

Potential economic viability of two proposed rifapentine-based regimens for treatment of latent tuberculosis infection

Rationale

Rifapentine-based regimens for treating latent tuberculosis infection (LTBI) are being considered for future clinical trials, but even if they prove effective, high drug costs may limit their economic viability.

Objectives

To inform clinical trial design by estimating the potential costs and effectiveness of rifapentine-based regimens for treatment of latent tuberculosis infection (LTBI).

Methods

We used a Markov model to estimate cost and societal benefits for three regimens for treating LTBI: Isoniazid/rifapentine daily for one month, isoniazid/rifapentine weekly for three months (self-administered and directly-observed), and isoniazid daily for nine months; a strategy of “no treatment” used for comparison. Costs, quality-adjusted life-years gained, and instances of active tuberculosis averted were calculated for all arms.

Results

Both daily isoniazid/rifapentine for one month and weekly isoniazid/rifapentine for three months were less expensive and more effective than other strategies under a wide variety of clinically plausibly parameter estimates. Daily isoniazid/rifapentine for one month was the least expensive and most effective regimen.

Conclusions

Daily isoniazid/rifapentine for one month and weekly isoniazid/rifapentine for three months should be studied in a large-scale clinical trial for efficacy. Because both regimens performed well even if their efficacy is somewhat reduced, study designers should consider relaxing non-inferiority boundaries.

Cost-effectiveness of QuantiFERON-TB test vs. tuberculin skin test in the diagnosis of latent tuberculosis infection

OBJECTIVE

To evaluate the cost-effectiveness of the tuberculin skin test (TST), the QuantiFERON-TB Gold test (QFT) and a combination of TST and QFT (TST+QFT) for diagnosing latent tuberculosis infection (LTBI) in France in a bacille Calmette-Guérin (BCG) vaccinated population.

METHODS

A decision analysis model evaluated three strategies among simulated adults in close contact with tuberculosis (TB). We calculated direct lifetime medical costs, life expectancies and incremental cost-effectiveness ratios (ICERs).

RESULTS

The discounted direct medical costs of care per patient of no testing, TST, QFT and TST+QFT were respectively euro417, euro476, euro443 and euro435, while discounted life expectancies were respectively 25.030, 25.071, 25.073 and 25.062 years. TST had higher costs and lower efficacy than QFT; TST+QFT was associated with an ICER of euro560 per year of life gained (YLG) compared to no testing, and QFT was associated with an ICER of euro730/YLG compared to TST+QFT. The only scenario where QFT was associated with an ICER of >euro75 000/YLG was when the prevalence of LTBI around TB was low (<5%) and TST specificity high (>90%).

CONCLUSIONS

In France, for the diagnosis of LTBI after close contact with TB, the TST is more expensive and less effective than QFT. Although it is more expensive, QFT is more effective and cost-effective than TST+QFT under a wide range of realistic test performance scenarios.