title: Cost-effectiveness of Quantiferon®-TB Gold-in-Tube versus tuberculin skin testing for contact screening and treatment of latent tuberculosis infection in Brazil.
abstract: 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.
  
  
  RESULTS
  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.
authors.affiliation: Internal Medicine Post-Graduation Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ricardo.steffen@gmail.com
authors.forename: Ricardo Ewbank
authors.initials: RE
authors.lastname: Steffen
authors.forename: Rosângela
authors.initials: R
authors.lastname: Caetano
authors.forename: Márcia
authors.initials: M
authors.lastname: Pinto
authors.forename: Diogo
authors.initials: D
authors.lastname: Chaves
authors.forename: Rossini
authors.initials: R
authors.lastname: Ferrari
authors.forename: Mayara
authors.initials: M
authors.lastname: Bastos
authors.forename: Sandra Teixeira
authors.initials: ST
authors.lastname: de Abreu
authors.forename: Dick
authors.initials: D
authors.lastname: Menzies
authors.forename: Anete
authors.initials: A
authors.lastname: Trajman
mesh_terms: D001938:Brazil; D016358:Contact Tracing / Q000191:economics / Q000379:methods; D003362:Cost-Benefit Analysis; D003663:Decision Trees; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000191:economics*; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000191:economics*; D008403:Mass Screening / Q000191:economics; D017059:Models, Econometric; D014374:Tuberculin Test / Q000191:economics*