Cost-effectiveness analysis of strategies using new immunological diagnostic tests of latent tuberculosis infection before TNF-blockers therapy

Summary Several tests have been proposed to detect latent tuberculosis (LTB). Objective To evaluate the cost-effectiveness of different interferon-gamma release assays based strategies used to screen LTB before tumour necrosis factor (TNF) blockers initiation. Methods Consecutive patients with rheumatoid arthritis, spondyloarthritis or Crohn's disease for whom TNF-blockers were considered, were recruited in 15 tertiary care centres. All were screened for LTB with tuberculin skin test (TST), QuantiFERON TB Gold ® in tube (QFT) and T-SPOT.TB ® (TSpot) on the same day. Cost-minimization and cost-effectiveness analysis, testing 8 screening test combinations, were conducted. Effectiveness was defined as the percentage of LTB treatment avoided and compared with TST alone. Cost were elicited in the payer perspective, included all the costs related to the screening procedure. Results No tuberculosis reactivation was observed after TNF-blocker initiation. TST followed by QFT if TST was positive was found as the best screening strategy, i.e. the less costly (−54 € compared to reference) and most effective (effectiveness 0.93), resulting in an incremental cost-effectiveness ratio of −192 € per treatment avoided. A probabilistic sensitivity analysis confirmed this result in 72.3% of simulations. Conclusion TST followed by QFT if TST was positive is the most cost-effective strategy in screening for LTB in patients before starting anti-TNF therapy. TrialRegNo NCT00811343 .