The aim of the present study was to compare the performance of the interferon (IFN)-c tests (QuantiFERON1-TB Gold In-Tube (QFT-G-IT) and T-SPOT1.TB) with the tuberculin skin test (TST) in diagnosing tuberculosis (TB) infection in children, and to analyse discordant results.This was a prospective study including 98 children from contact-tracing studies and 68 children with TST indurations o5 mm recruited during public health screenings.Positive IFN-c tests results were associated with risk of exposure (p,0.0001). T-SPOT.TB was positive in 11 (78.6%) out of 14 cases with active TB and QFT-G-IT in nine (64.3%) out of 14 cases. Sensitised T-cells against Mycobacterium avium were detected in six out of 12 children not vaccinated with bacille Calmette-Guérin (BCG), a TST induration 5-9 mm in diameter and both IFN-c tests negative. In concordant IFN-c tests results, a positive correlation was found (p50.0001) between the number of responding cells and the amount of IFN-c released. However, in discordant IFN-c tests results this correlation was negative (p50.371): an increase in the number of spot-forming cells correlated with a decrease in the amount of IFN-c released.The use of IFN-c tests is helpful for the diagnosis of TB infection, avoiding cross-reactions with BCG immunisation and nontuberculous mycobacterial infections. The analysis of highly discordant results requires further investigation to elucidate possible clinical implications.KEYWORDS: Agreement, children, interferon-c release assays, nontuberculous mycobacterial sensitins, tuberculin skin test, tuberculosis I n 2007, the estimated global incidence of tuberculosis (TB) cases was 9.27 million. Approximately 11% of these cases were children. In the developed world, the estimated proportion of children with TB is around 3-6%, but in developing countries this percentage can reach 15-20%, with an approximate mortality of 30% [1]. Latent TB infection (LTBI) treatment is an essential strategy to eliminate TB [2], although in order to achieve any epidemiological impact, this strategy must target groups with a high risk of infection and development of the disease if they become infected. Children merit special consideration, as they can develop the disease very quickly after primary infection, with the most severe forms prevailing in younger children [3].The advantages of techniques based on the detection of interferon (IFN)-c secreted by effector T-cells stimulated with specific Mycobacterium tuberculosis antigens to diagnose LTBI over the tuberculin skin test (TST) are the lack of cross-reactivity with vaccinal Mycobacterium bovis bacille Calmette-Guérin (BCG) strains and nontuberculous mycobacteria (NTM), and the absence of booster effect [4,5]. These antigens are the early secretory antigenic target (ESAT)-6 and culture filtrate protein (CFP)-10 encoded in region of difference (RD)1, and TB7.7 encoded in RD11, which are absent in all BCG strains and in the majority of NTM. Two commercial in vitro assays based on this technology are currently availab...
The aim of the study was to assess the budgetary impact of funding smoking-cessation drugs in COPD patients in Spain. A hybrid model (cohort and Markov) was developed for a 5-year time horizon. Only approved cessation drugs (varenicline, bupropion, and nicotine replacement therapy) were considered. Irrespective of the drug, the model allowed for an initial cessation attempt, and up to three additional attempts in case of failure or smoking relapse during a 5-year period. Drug effectiveness was based on controlled clinical trials. National Health System perspective was applied; therefore, only medical resources were included. The pharmaceutical costs for smoking-cessation drugs, extra medical follow-up as a consequence of public reimbursement, and annual savings for health costs avoided due to stopping smoking were considered. The model estimated that 17,756 COPD patients would stop smoking if public funding was available, compared with 1,303 without reimbursement. In the reimbursement scenario, the savings accounted for a total of €48.0 million, compensating for expenditures on drugs and medical visits (€40.4 million). Accumulated total additional savings in 5 years (€4.3 million) compared with the scenario without reimbursement was shown. Sensitivity analyses supported the results robustness. Funding smoking-cessation drugs in COPD patients seems to be an efficient option and a National Health System drug reimbursement scheme would represent a cost-saving policy in Spain.
BackgroundThe aim of the study was to assess the correlation between the tuberculin skin test (TST) and in vitro interferon-gamma released assays (IGRAs) with risk factors for the spread of infection in smear positive pulmonary tuberculosis (TB) contacts.MethodsWe recruited prospective contacts with smear positive pulmonary TB cases. We looked at human immunodeficiency virus (HIV) infection and other conditions of immunosuppression, presence of BCG vaccination and the degree of exposure to the index case. Patients underwent the TST, chest radiography, sputum analysis when necessary, and IGRA assays (QFN-G-IT and T-SPOT.TB). Presence of cough, diagnostic delay (days between first symptoms and TB diagnostic), contact conditions: room size (square meters) and index of overcrowding (square meters per person) were investigated in the index case.Results156 contacts (119 adults, 37 children) of 66 TB patients were enrolled, 2.4 (1-14) contacts per TB case. The positivity of the TST did not correlate with the risk factors studied: presence of cough (p = 0.929); delayed diagnosis (p = 0.244); room size (p = 0.462); overcrowding (p = 0.800). Both QFN-G-IT and T-SPOT.TB, showed significant association with cough (p = 0.001, and p = 0.007) and room size (p = 0.020, and p = 0.023), respectively.ConclusionsBoth IGRA associated better than TST with certain host-related risk factors involved in the transmission of disease, such as the presence of cough.
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