Cost-effectiveness of interferon-γ release assay for screening of latent tuberculosis infection in individuals with schizophrenia.

Schizophrenia is recognized as a significant risk factor for tuberculosis (TB). This study aimed to evaluate the effectiveness and cost-effectiveness of interferon-γ release assay (IGRA) with preventive treatment for screening of latent tuberculosis infection (LTBI) in individuals with schizophrenia. A state transition model was developed from a healthcare payer perspective on a lifetime horizon. Ten strategies were compared by combining two different tests for LTBI, i.e. IGRA and tuberculin skin test (TST), and five different preventive treatments, i.e. 9-month isoniazid (9H), 3-month isoniazid and rifapentine (3HP) by directly observed therapy, 3HP by self-administered therapy, 3-month isoniazid and rifampin (3RH), and 4-month rifampin (4R). The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios, drug-sensitive tuberculosis (DS-TB) cases, and TB-related deaths. For both bacillus Calmette-Guérin (BCG)-vaccinated and non-BCG-vaccinated individuals, IGRA with 4R was the most cost-effective and TST with 3RH was the least effective. Among schizophrenic individuals in Japan, IGRA with 4R saved US$17.8 million, increased 58,981 QALYs and 935 LYs, and prevented 222 DS-TB cases and 75 TB-related deaths compared with TST with 3RH. In individuals with schizophrenia, IGRA with 4R is recommended for LTBI screening with preventive treatment to reduce costs, morbidity, and mortality from TB.

Cost-effectiveness of human T-cell leukemia virus type 1 (HTLV-1) antenatal screening for prevention of mother-to-child transmission.

BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy-tropical spastic paraparesis (HAM/TSP) with a poor prognosis. This study aimed to evaluate the cost-effectiveness and health impact of HTLV-1 antenatal screening. METHODOLOGY/PRINCIPAL FINDINGS: A state-transition model was developed for HTLV-1 antenatal screening and no screening over a lifetime horizon from a healthcare payer perspective. A hypothetical cohort of 30-year-old individuals was targeted. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios (ICERs), HTLV-1 carriers, ATL cases, HAM/TSP cases, ATL-associated deaths, and HAM/TSP-associated deaths. The willingness-to-pay (WTP) threshold was set at US$50,000 per QALY gained. In the base-case analysis, HTLV-1 antenatal screening (US$76.85, 24.94766 QALYs, 24.94813 LYs, ICER; US$40,100 per QALY gained) was cost-effective compared with no screening (US$2.18, 24.94580 QALYs, 24.94807 LYs). Cost-effectiveness was sensitive to the maternal HTLV-1 seropositivity rate, HTLV-1 transmission rate with long-term breastfeeding from HTLV-1 seropositive mothers to children, and the cost of the HTLV-1 antibody test. HTLV-1 antenatal screening was cost-effective when the maternal HTLV-1 seropositivity rate was greater than 0.0022 and the cost of the HTLV-1 antibody test was lower than US$94.8. Probabilistic sensitivity analysis using a second-order Monte-Carlo simulation showed that HTLV-1 antenatal screening was 81.1% cost-effective at a WTP threshold of US$50,000 per QALY gained. For 10,517,942 individuals born between 2011 and 2021, HTLV-1 antenatal screening costs US$785 million, increases19,586 QALYs and 631 LYs, and prevents 125,421 HTLV-1 carriers, 4,405 ATL cases, 3,035 ATL-associated deaths, 67 HAM/TSP cases, and 60 HAM/TSP-associated deaths, compared with no screening over a lifetime. CONCLUSION/SIGNIFICANCE: HTLV-1 antenatal screening is cost-effective and has the potential to reduce ATL and HAM/TSP morbidity and mortality in Japan. The findings strongly support the recommendation for HTLV-1 antenatal screening as a national infection control policy in HTLV-1 high-prevalence countries.

A Population-Based Helicobacter pylori Eradication Strategy Is More Cost-Effective than Endoscopic Screening.

BACKGROUND: Helicobacter pylori (HP) eradication therapy is an efficient primary prevention method to reduce gastric cancer development. In Japan, biennial endoscopic screening for individuals aged 50 years and older is currently conducted as a national gastric cancer prevention program. AIMS: We aimed to evaluate which strategy was the most optimal and cost-effective among HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening as a national gastric cancer prevention program. METHODS: We developed a state-transition model for HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening using a healthcare payer perspective and a lifetime horizon. We targeted a hypothetical cohort of the Japanese population in their 20 s to 80 s. The main outcomes were costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer. We performed one-way, two-way, and probabilistic sensitivity analyses. RESULTS: HP eradication strategy was more cost-effective than endoscopic screening at any interval in all age groups. Cost-effectiveness was sensitive to HP infection rate. Cost-effective acceptability curves by Monte Carlo simulations for 10,000 trials demonstrated that HP eradication strategy was 100% cost-effective at a willingness-to-pay threshold of US$50,000 per QALY gained in all age groups. Over a lifetime, HP eradication strategy saves US$28.07 billion, increases 37.16 million QALYs, prevents 4.47 million gastric cancer cases, and saves 319,870 lives from gastric cancer. CONCLUSION: A population-based HP eradication strategy is optimal and cost-effective for a national gastric cancer prevention program in Japan, replacing the current secondary prevention-focused biennial endoscopic screening.

Cost-effectiveness and health impact of lung cancer screening with low-dose computed tomography for never smokers in Japan and the United States: a modelling study.

BACKGROUND: Never smokers in Asia have a higher incidence of lung cancer than in Europe and North America. We aimed to assess the cost-effectiveness of lung cancer screening with low-dose computed tomography (LDCT) for never smokers in Japan and the United States. METHODS: We developed a state-transition model for three strategies: LDCT, chest X-ray (CXR), and no screening, using a healthcare payer perspective over a lifetime horizon. Sensitivity analyses were also performed. Main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios (ICERs), and deaths from lung cancer. The willingness-to-pay level was US$100,000 per QALY gained. RESULTS: LDCT yielded the greatest benefits with the lowest cost in Japan, but the ICERs of LDCT compared with CXR were US$3,001,304 per QALY gained for American men and US$2,097,969 per QALY gained for American women. Cost-effectiveness was sensitive to the incidence of lung cancer. Probabilistic sensitivity analyses demonstrated that LDCT was cost-effective 99.3-99.7% for Japanese, no screening was cost-effective 77.7% for American men, and CXR was cost-effective 93.2% for American women. Compared with CXR, LDCT has the cumulative lifetime potential for 60-year-old Japanese to save US$117 billion, increase 2,339,349 QALYs and 3,020,102 LYs, and reduce 224,749 deaths, and the potential for 60-year-old Americans to cost US$120 billion, increase 48,651 QALYs and 67,988 LYs, and reduce 2,309 deaths. CONCLUSIONS: This modelling study suggests that LDCT screening for never smokers has the greatest benefits and cost savings in Japan, but is not cost-effective in the United States. Assessing the risk of lung cancer in never smokers is important for introducing population-based LDCT screening.

Cost-effectiveness of MicroRNA for Pancreatic Cancer Screening in Patients With Diabetes.

OBJECTIVES: The study aimed to assess the cost-effectiveness of microRNA compared with carbohydrate antigen 19-9, abdominal ultrasound, magnetic resonance imaging, endoscopic ultrasound, computed tomography, positron emission tomography, and no screening for pancreatic cancer (PC) screening in patients with diabetes. METHODS: We developed a state-transition model from a health care payer perspective and a lifetime horizon. We targeted 3 hypothetical cohorts of patients with long-standing type 2 diabetes (LSD), new-onset diabetes (NOD), and LSD having intraductal papillary mucinous neoplasm (IPMN), aged 40, 50, 60, and 70 years. The main outcomes were costs, quality-adjusted life-years, life expectancy life-years, incremental cost-effectiveness ratios, and deaths from PC. RESULTS: In the base-case analysis, abdominal ultrasound in patients with LSD and microRNA in patients with NOD and LSD having IPMN were the most cost-effective for all age groups. Cost-effectiveness was sensitive to PC incidence and the cost of microRNA. Probabilistic sensitivity analysis showed that microRNA was 42% to 54% cost-effective for NOD and 76% to 78% cost-effective for LSD having IPMN at a willingness-to-pay level of US $100,000 per quality-adjusted life-year gained. MicroRNA prevented 30,641 PC deaths in diabetic patients compared with no screening. CONCLUSIONS: In patients with NOD and LSD having IPMN, microRNA-based PC screening is cost-effective and recommended for early PC detection.

Economic and health impacts of introducing Helicobacter pylori eradication strategy into national gastric cancer policy in Japan: A cost-effectiveness analysis.

BACKGROUND: Helicobacter pylori (H. pylori) eradication reduces gastric cancer risk. Since 2013, a population-wide H. pylori eradication strategy for patients with chronic gastritis has begun to prevent gastric cancer in Japan. The aim of this study was to evaluate the economic and health effects of H. pylori eradication strategy in national gastric cancer prevention program. MATERIALS AND METHODS: We developed a cohort state-transition model for H. pylori eradication and no eradication over a lifetime horizon from a healthcare payer perspective, and performed one-way and probabilistic sensitivity analyses. We targeted a hypothetical cohort of H. pylori-positive patients aged 20, 30, 40, 50, 60, 70, and 80. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer. RESULTS: H. pylori eradication was more effective and cost-saving for all age groups than no eradication. Sensitivity analyses showed strong robustness of the results. From 2013-2019 for 8.50 million patients, H. pylori eradication saved US$3.75 billion, increased 11.11 million QALYs and 0.45 million LYs, and prevented 284,188 cases and 65,060 deaths. For 35.59 million patients without eradication, H. pylori eradication has the potential to save US$14.82 billion, increase 43.10 million QALYs and 1.66 million LYs, and prevent 1,084,532 cases and 250,256 deaths. CONCLUSIONS: National policy using population-wide H. pylori eradication to prevent gastric cancer has significant cost savings and health impacts for young-, middle-, and old-aged individuals in Japan. The findings strongly support the promotion of H. pylori eradication strategy for all age groups in high-incidence countries.

Endoscopy Is Cost-Effective for Gastric Cancer Screening After Successful Helicobacter pylori Eradication.

BACKGROUND: After successful Helicobacter pylori eradication, patients with gastric mucosal atrophy are at high risk of gastric cancer. Endoscopy can detect early gastric cancer with high sensitivity. AIMS: This study aimed to assess the cost-effectiveness of annual endoscopy versus biennial endoscopy versus no screening for gastric cancer screening in patients after successful Helicobacter pylori eradication. METHODS: We developed decision trees with Markov models for a hypothetical cohort of patients aged 50 years after successful Helicobacter pylori eradication over a lifetime horizon from a healthcare payer perspective. Main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs) with discounting at a fixed annual rate of 3%, and incremental cost-effectiveness ratios (ICERs). RESULTS: In a base-case analysis, biennial endoscopy (US$4305, 19.785QALYs, 19.938LYs) was more cost-effective than annual endoscopy (US$7516, 19.808QALYs, 19.958LYs, ICER; US$135,566/QALY gained) and no screening (US$14,326, 19.704QALYs, 19.873LYs). In scenario analyses, biennial endoscopy for patients with mild-to-moderate gastric mucosal atrophy and annual endoscopy for patients with severe gastric mucosal atrophy were the most cost-effective. Cost-effectiveness was sensitive to incidence of gastric cancer and the proportion of stage I. Probabilistic sensitivity analyses using Monte Carlo simulation demonstrated that at a willingness-to-pay level of US$100,000/QALY gained, biennial endoscopy was optimal 99.9% for patients with mild-to-moderate gastric mucosal atrophy, and that annual endoscopy was optimal 98.4% for patients with severe gastric mucosal atrophy. CONCLUSIONS: Based on cancer risk assessment of gastric mucosal atrophy and cost-effectiveness results, annual or biennial endoscopic surveillance could be established for patients after successful Helicobacter pylori eradication.

Cost-effectiveness of Abdominal Ultrasound Versus Magnetic Resonance Imaging for Pancreatic Cancer Screening in Familial High-Risk Individuals in Japan.

OBJECTIVE: The aim of the study was to assess cost-effectiveness of abdominal ultrasound, magnetic resonance imaging, endoscopic ultrasound, computed tomography, positron emission tomography, and no screening for pancreatic cancer screening in familial high-risk individuals (HRIs). METHODS: We developed decision trees with Markov models for a hypothetical cohort of familial HRIs at the age of 50 year using a healthcare sector perspective and a lifetime horizon. Main outcomes were costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. RESULTS: In a base-case analysis, abdominal ultrasound was the most cost-effective (US $11,035, 17.4875 QALYs). Magnetic resonance imaging yielded the best benefits. Cost-effectiveness was sensitive to the incidence of pancreatic cancer. Endoscopic ultrasound was more cost-effective than abdominal ultrasound when the incidence of pancreatic cancer was greater than 0.008 and under 0.016. Magnetic resonance imaging was more cost-effective than endoscopic ultrasound when the incidence of pancreatic cancer was greater than 0.016. Probabilistic sensitivity analysis using Monte-Carlo simulation for 10,000 trials demonstrated that abdominal ultrasound was cost-effective 76% of the time at a willingness-to-pay threshold of US $50,000/QALY gained. CONCLUSIONS: Abdominal ultrasound is the most cost-effective and recommended for pancreatic cancer screening in familial HRIs in Japan. Evaluating the risk of pancreatic cancer among familial HRIs as a target for screening is significant.

Cost-effectiveness of IGRA/QFT-Plus for TB screening of migrants in Oman.

OBJECTIVE: To estimate the cost of a screening program for identifying latent tuberculosis (TB) infections in migrants to Oman. METHODS: A Markov model was used to estimate the cost of screening using an interferon-gamma release assay (IGRA) applied to all migrants from high TB endemic countries, followed by preventive TB treatment. RESULTS: The model compared seven different scenarios, with a comparison of the direct cost and the quality-adjusted life-years (QALYs) saved. CONCLUSIONS: IGRA testing followed by 3 months of preventive treatment with rifapentine/isoniazid (3HP) was the most cost-effective intervention.

Cost-effectiveness of Helicobacter pylori test and eradication versus upper gastrointestinal series versus endoscopy for gastric cancer mortality and outcomes in high prevalence countries.

Background: The latest version of Japanese guidelines for effective secondary prevention of gastric cancer recommend upper gastrointestinal series (UGI) and endoscopy in adults 50 years of age and older. A Helicobacter pylori antibody test and eradication (H. pylori screening) reduces gastric cancer risk. Objective: This study aimed to evaluate the cost-effectiveness of H. pylori screening, compared to UGI and endoscopy in high prevalence countries. Methods: We developed decision trees with Markov models using a healthcare payer perspective and a lifetime horizon. Targeted populations were hypothetical cohorts of asymptomatic individuals at the age of 50, 60, 70 and 80 years. We calculated per-person costs and effectiveness with discounting at a fixed annual rate of 3% and compared incremental cost-effectiveness ratios. Results: H. pylori screening was cost-saving and more cost-effective for individuals at the age of 50, 60, 70, and 80 than UGI and endoscopy. One-way and multiway sensitivity analyses showed the robustness of the cost-effectiveness results. Probabilistic sensitivity analyses using Monte-Carlo simulation for 10,000 trials demonstrated that H. pylori screening was cost-effective 100% of the time at a willingness-to-pay level of US$50,000/QALY gained. Conclusions: H. pylori screening for the adults 50 years of age and older could be cost-effective compared to UGI and endoscopy in high prevalence countries. The main reasons for the superiority of H. pylori screening are that an H. pylori antibody test has a higher sensitivity and specificity than UGI and endoscopy and the benefits to reduce gastric cancer incidence and mortality.

Cost effectiveness of interferon-gamma release assay for tuberculosis screening using three months of rifapentine and isoniazid among long-term expatriates from low to high incidence countries.

BACKGROUND: Long-term expatriates from low to high tuberculosis (TB) incidence countries get high rates of active TB and latent TB infection (LTBI). TB screening for expatriates is important for occupational health. Interferon-gamma release assays are more accurate than tuberculin skin test (TST). Rifapentine plus isoniazid for 3 months (3HP) is as effective as 9 months of isoniazid (9H) with a higher treatment-completion rate. METHODS: Decision trees and Markov models were constructed using a societal perspective on a lifetime horizon. The target population was a hypothetical cohort of 30 year-old expatriates. Seven strategies; TST with 3HP or 9H, QuantiFERON®-TB Gold In-Tube (QFT) with 3HP or 9H, T-SPOT®.TB (TSPOT) with 3HP or 9H and chest X-ray examination (CXR) were modeled. The main outcome measure of effectiveness was quality-adjusted life-years (QALYs) gained. RESULTS: QFT with 3HP yielded the greatest benefits with the lowest cost ($US 674.8; 25.95660 QALYs [year 2012 values]). CXR was the least cost-effective ($US 13,666.8; 24.62917 QALYs). Cost-effectiveness was sensitive to adherence rate of 3HP and QFT specificity, but not to BCG vaccination rate. CONCLUSIONS: Entry LTBI screening using QFT treated with 3HP is recommended on the basis of cost effectiveness among long-term expatriates from low to high incidence countries.

Cost effectiveness of high resolution computed tomography with interferon-gamma release assay for tuberculosis contact investigation.

BACKGROUND: Tuberculosis contact investigation is one of the important public health strategies to control tuberculosis worldwide. Recently, high resolution computed tomography (HRCT) has been reported as a more accurate radiological method with higher sensitivity and specificity than chest X-ray (CXR) to detect active tuberculosis. In this study, we assessed the cost effectiveness of HRCT compared to CXR in combination with QuantiFERON(®)-TB Gold In-Tube (QFT) or the tuberculin skin test (TST) for tuberculosis contact investigation. METHODS: We constructed Markov models using a societal perspective on the lifetime horizon. The target population was a hypothetical cohort of immunocompetent 20-year-old contacts with smear-positive tuberculosis patients in developed countries. Six strategies; QFT followed by CXR, QFT followed by HRCT, TST followed by CXR, TST followed by HRCT, CXR alone and HRCT alone were modeled. All costs and clinical benefits were discounted at a fixed annual rate of 3%. RESULTS: In the base-case analysis, QFT followed by HRCT strategy yielded the greatest benefit at the lowest cost ($US 6308.65; 27.56045 quality-adjusted life-years [QALYs])[year 2012 values]. Cost-effectiveness was sensitive to BCG vaccination rate. CONCLUSIONS: The QFT followed by HRCT strategy yielded the greatest benefits at the lowest cost. HRCT chest imaging, instead of CXR, is recommended as a cost effective addition to the evaluation and management of tuberculosis contacts in public health policy.

Cost effectiveness of the interferon-γ release assay for tuberculosis screening of hemodialysis patients.

BACKGROUND: The incidence of tuberculosis and latent tuberculosis infection in hemodialysis patients is higher than that in the general population. Our aim was to assess the cost effectiveness of QuantiFERON(®)-TB Gold In-Tube (QFT) compared with the tuberculin skin test (TST) and the chest x-ray examination (CXR) for tuberculosis screening of hemodialysis patients. METHODS: Markov models were constructed using a societal perspective on the lifetime horizon. The target population was a hypothetical cohort of 40-year-old hemodialysis patients. All costs and clinical benefits were discounted at a fixed annual rate of 3%. Three strategies QFT, TST and CXR were modeled. RESULTS: In the base-case analysis, QFT yielded the greatest benefits at the lowest cost [US$7694.43; 4.19 258 quality-adjusted life-years (QALYs)] compared with the TST (US$9337.81; 4.18 543 QALYs) and CXR (US$12 951.36; 4.14 821 QALYs) (year 2012 values). The cost effectiveness was sensitive to the the Bacillus Calmette Guérin (BCG) vaccination rate. The TST strategy was more cost effective than the QFT strategy at the willingness-to-pay level of US$50 000/QALY gained when the rate of BCG vaccination was 0.18 or lower. The cost-effectiveness acceptability curve of 40-year-old patients by Monte Carlo simulations for 10 000 trials demonstrated that the QFT was the most cost effective with a value of 100% at all willingness-to-pay levels compared with TST and CXR. CONCLUSIONS: The QFT is the most cost-effective method for the tuberculosis screening of hemodialysis patients. Interferon-γ release assays should be recommended in clinical practice on the basis of their cost effectiveness, as well as their higher specificity, compared with TST and CXR.

Cost effectiveness of interferon-gamma release assay for school-based tuberculosis screening.

PURPOSE: To assess the cost effectiveness of school-based tuberculosis (TB) screening using QuantiFERON®-TB Gold In-Tube (QFT) versus the tuberculin skin test (TST) and chest x-ray examination (CXR). METHODS: We constructed Markov models of first-year high-school and university students, using a societal perspective, and followed them up until the age of 80 years. Three strategies (QFT, TST, and CXR) were modeled. All costs and clinical benefits were discounted at a fixed annual rate of 3%. RESULTS: In the base-case analyses of 16-year-old high-school students and 19-year-old university students, the QFT strategy yielded the greatest benefits at the lowest cost [in year 2009 values] (16-year-olds: $US627.89, 29.69835 quality-adjusted life-years [QALYs]; 19-year-olds: $US646.04, 29.15361 QALYs), compared with the TST strategy (16-year-olds: $US943.50, 29.69767 QALYs; 19-year-olds: $US998.62, 29.15288 QALYs) and the CXR strategy (16-year-olds: $US7286.24, 29.69532 QALYs; 19-year-olds: $US7305.19, 29.14911 QALYs). On one-way sensitivity analyses, the bacillus Calmette-Guérin (BCG) vaccination rate was not sensitive to the TST strategy. On probabilistic sensitivity analysis, the QFT strategy was the most cost effective, with a willingness-to-pay level of $US50 000/QALY gained. CONCLUSION: The QFT strategy provided the greatest benefits at the lowest cost for school-based TB screening. There appears to be little role for TST or CXR in screening of school populations. Current practices using either TST or CXR screening should be reconsidered on the basis of cost effectiveness.

Cost effectiveness of interferon-gamma release assay versus chest X-ray for tuberculosis screening of BCG-vaccinated elderly populations.

BACKGROUND: The prevalence of tuberculosis (TB) in the elderly is higher than that in the general population, and elderly populations are considered a high-risk group. Currently, annual TB screening of Bacille Calmette-Guérin (BCG)-vaccinated people aged over 65 years is performed by an annual chest x-ray examination (CXR) in Japan. Interferon-gamma release assays (QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube [QFT]) are new alternatives to the tuberculin skin test to diagnose latent TB infection (LTBI) that have no cross-reactivity with the BCG vaccine. We evaluated the cost effectiveness of QFT versus CXR versus no screening in BCG-vaccinated elderly populations. METHODS: We constructed a Markov model to evaluate the cost effectiveness of QFT, CXR, and no screening. The target population was a hypothetical cohort of 1000 immunocompetent 65-year-olds, using a societal perspective and a lifetime horizon. All costs and clinical benefits were discounted at a fixed annual rate of 3%. RESULTS: In the base-case analysis, a no-screening strategy resulted in the lowest cost ($US303.51; 14.6475 quality-adjusted life-years [QALYs]) compared with CXR ($US393.22; 14.6477 QALYs) and QFT ($US525.45; 14.6516 QALYs) [year 2008 values]. The sensitivity of QFT, as well as the prevalence of TB and LTBI, influenced the cost effectiveness; when the sensitivity of QFT was higher than 0.89, QFT became more cost effective than providing no screening. As the prevalence of LTBI and TB increased, the QFT strategy became progressively more cost effective. CONCLUSIONS: Providing no routine TB screening is currently the most cost-effective strategy for BCG-vaccinated elderly populations in Japan. There appears to be little role for CXR in TB screening of elderly populations. These findings may be applicable to other countries with intermediate and high TB risks when choosing optimal TB screening of elderly populations.

Cost effectiveness of interferon-gamma release assay for tuberculosis screening of rheumatoid arthritis patients prior to initiation of tumor necrosis factor-α antagonist therapy.

BACKGROUND: The prevalence of tuberculosis (TB) in rheumatoid arthritis (RA) patients is higher than that in the general population, and RA patients are considered a high-risk group. Currently, TB screening of RA patients receiving immunosuppressive therapy such as tumor necrosis factor-α (TNFα) antagonists is performed by the tuberculin skin test (TST) in Japan. Interferon-gamma release assays (QuantiFERON®-TB Gold In-Tube [QFT] and T-SPOT.TB®) are new alternatives to the TST to diagnose latent TB infection (LTBI) and active TB, and offer higher specificity and no cross-reactivity with Bacillus Calmette-Guérin (BCG) vaccine. We evaluated the cost effectiveness of QFT versus TST in non-BCG-vaccinated and BCG-vaccinated RA patients. METHODS: We constructed a Markov model to evaluate the cost effectiveness of QFT and TST. The target population is a hypothetical cohort of 1000 RA patients, using a societal perspective and the lifetime horizon. All costs and clinical benefits were discounted at a fixed annual rate of 3%. RESULTS: In base-case analysis, the QFT strategy was the most cost effective ($US1044.52; 23.03499 quality-adjusted life-years [QALYs]) compared with the TST strategy for non-BCG-vaccinated RA patients ($US1824.61; 22.98153 QALYs) and for BCG-vaccinated RA patients ($US2096.34; 22.98153 QALYs) [year 2009 values]. The incidence of TB in RA patients with TNFα antagonist therapy influenced the cost effectiveness. When the incidence of TB in RA patients with TNFα antagonist therapy is under 0.00066, the TST strategy is more cost effective than the QFT strategy. CONCLUSIONS: QFT screening is more effective and less costly than the TST for both BCG-vaccinated and non-BCG-vaccinated RA patients prior to TNFα antagonist therapy in Japan. These findings may be applicable to other countries when choosing optimal LTBI screening of RA patients.

Cost effectiveness of interferon-gamma release assay for tuberculosis contact screening in Japan.

BACKGROUND: Nearly the entire population of Japan has been vaccinated with Bacillus Calmette-Guerin (BCG), which causes a false-positive result in the tuberculin skin test (TST). The interferon-gamma release assay QuantiFERON-TB Gold (QFT) is a new alternative to the TST that can be used to screen for latent tuberculosis infection and active tuberculosis, as it has no cross-reactivity with BCG. METHODS: We constructed a Markov model to evaluate the cost effectiveness of the QFT for tuberculosis contact screening. The target population is a hypothetical cohort of 1000 immunocompetent 20-year-old individuals who have had contact with sputum-smear-positive pulmonary tuberculosis patients. The analysis was conducted from a societal perspective over the lifetime of a contact. We compared the QFT-alone strategy with the TST followed by QFT (TST/QFT) strategy and the TST-alone strategy. RESULTS: In a base-case analysis, the QFT-alone strategy was dominant ($US 471.54; 28.1099 quality-adjusted life-years [QALYs]), compared with the TST/QFT strategy ($US 500.55; 28.1087 QALYs) and the TST-alone strategy ($US573.98; 28.1079 QALYs). The incremental cost-effectiveness ratio of the QFT-alone strategy was a cost saving of $US23 043.5/QALY gained compared with the TST/QFT strategy. On one-way sensitivity analysis, TST specificity and the prevalence of tuberculosis/latent tuberculosis infection affected the cost effectiveness. The probabilistic analysis showed that the QFT-alone strategy has a 95% chance of being cost effective at a threshold ratio of $US2.10/QALY gained, compared with the TST/QFT strategy. CONCLUSION: The QFT-alone strategy is the most cost effective for tuberculosis contact screening in Japan.

[Utility of QuantiFERON TB-2G for tuberculosis contact investigations in public health services].

OBJECTIVE: The objective of the present study was to examine the utility of QuantiFERON TB-2G (QFT) in tuberculosis contact investigations performed by a public health center. METHODS: Adachi City Public Health Center, Tokyo, started using QFT in its laboratory service in June, 2005. The results of QFT, as well as tuberculin skin tests (TSTs) performed in tuberculosis contact investigations in the 10 month period since then were here analyzed. QFT was carried out for 67 contacts two months after their last contact with the index case. TST was given simultaneously. RESULTS: Of the total of 67 contacts investigated during the period, 9 were positive for QFT, 5 were doubtful positive, and the remaining 53 were negative. Among 48 subjects tested with TST, 22 had strong reactions with erythema > or = 30 mm, out of which 4 were positive for QFT. In addition, there were 5 QFT-positives among the remaining 26 with weak tuberculin reactions. These 9 subjects with positive QFT were indicated for chemoprophylaxis. CONCLUSIONS: Adachi City Public Health Center is pioneering the application of new technology for detection of latent tuberculosis infection in contact investigations of the inhabitants. As expected from trial findings, QFT was shown to be a useful tool in a practical setting for the purpose of detecting TB infection, with greater accuracy than with TST, independent of the history of BCG vaccination. This approach can help avoid both over-diagnosis and under-diagnosis.