title: Cost-effectiveness of alternative strategies for interferon-γ release assays and tuberculin skin test in tuberculous uveitis.
abstract: BACKGROUND
  Although tuberculous uveitis remains a major cause of ocular morbidity in the developing world, there is no consensus on which diagnostic test or testing strategy is the most cost effective. In this study we carried out a cost-effectiveness analysis to determine the most cost-effective diagnostic test strategy.
  
  
  METHODS
  In this prospective study, we recruited 102 patients from Singapore National Eye Centre with signs suggestive of tuberculous uveitis. Using prospective data from this cohort and from published meta-analyses, we modelled the incremental cost effectiveness of the following strategies: tuberculin skin test (TST) only; interferon-γ release assay (IGRA) only; IGRA following a positive TST result; and dual-test strategy, conducting TST and IGRA at presentation. Incremental cost-effectiveness ratios (ICERs) were calculated for each strategy and analysed using a willingness-to-pay threshold of $50,000 per quality-adjusted life year (QALY) gained.
  
  
  RESULTS
  In our population, the least cost effective was the IGRA-only strategy. The dual-test strategy was the most cost effective, with an improvement of 0.017 QALY at an incremental cost of $190 relative to the TST-only strategy (ICER $11,500); while the TST-only strategy was more cost effective than the third strategy, using IGRA following a positive TST result (ICER $3610). This remained consistent while varying the costs of IGRA and TST, the incidence of tuberculosis and tuberculous uveitis, as well as the diagnostic accuracy of IGRA and TST found in previous studies in various populations.
  
  
  CONCLUSIONS
  The dual-test strategy (performing TST and IGRA at presentation) was the most cost effective strategy for the diagnosis of tuberculous uveitis in our population.
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore Singapore Eye Research Institute, Singapore, Singapore Department of Ophthalmology, Yong Yoo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.affiliation: Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Hai V
authors.initials: HV
authors.lastname: Nguyen
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Sieh Yean
authors.initials: SY
authors.lastname: Kiew
authors.affiliation: Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore Singapore Eye Research Institute, Singapore, Singapore Department of Ophthalmology, Yong Yoo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Soon-Phaik
authors.initials: SP
authors.lastname: Chee
authors.affiliation: Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Eric
authors.initials: E
authors.lastname: Finkelstein
mesh_terms: D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use; D003362:Cost-Benefit Analysis; D005260:Female; D017048:Health Care Costs; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000191:economics*; D008297:Male; D008875:Middle Aged; D018803:Models, Economic; D011446:Prospective Studies; D019057:Quality-Adjusted Life Years; D012846:Singapore; D014374:Tuberculin Test / Q000191:economics*; D014392:Tuberculosis, Ocular / Q000175:diagnosis* / Q000188:drug therapy / Q000191:economics; D014605:Uveitis / Q000175:diagnosis* / Q000188:drug therapy / Q000191:economics
chemical_list: D000995:Antitubercular Agents
keywords: Diagnostic tests/Investigation; Infection; Inflammation