Data from: Screening of health care workers for tuberculosis: development and validation of a new health economic model to inform practice

BACKGROUND: Methods for determining cost-effectiveness of different
treatments are well established, unlike appraisal of non-drug
interventions, including novel diagnostics and biomarkers. OBJECTIVE: We
develop and validate a new health economic model by comparing
cost-effectiveness of tuberculin skin test, TST; blood test, IGRA; and TST
followed by IGRA in conditional sequence, in screening health care workers
for latent or active TB. DESIGN: We focus on healthy life years gained as
the benefit metric, rather than quality adjusted life years (QALYs) given
limited data to estimate quality-adjustments of life years with TB and
complications of treatment, like hepatitis. Healthy life years gained
refers to the number of TB or hepatitis cases avoided, and the increase in
life expectancy. We incorporate disease and test parameters informed by
systematic meta-analyses and clinical practice. Health and economic
outcomes of each strategy are modelled as a decision tree in Markov
chains, representing different health states informed by epidemiology.
Cost and effectiveness values are generated as the individual is cycled
through 20 years of the model. Key parameters undergo one-way and Monte
Carlo probabilistic sensitivity analyses. SETTING: Screening health care
workers in secondary and tertiary care. RESULTS: IGRA is the most
effective strategy, with incremental costs per healthy life year gained of
£10,614 - £20,929, base case, £8,021 - £18,348, market costs TST £45, IGRA
£90, IGRA specificities of 99% - 97%; mean (5%, 95%), £12,060 (£4,137 -
£38,418) by Monte Carlo analysis. CONCLUSIONS: Incremental costs per
healthy life year gained, a conservative estimate of benefit, are
comparable to the £20,000 - £30,000 NICE band for IGRA alone, across wide
differences in disease and test parameters. Health gains justify IGRA
costs, even if IGRA tests cost three times TST. This health economic model
offers a powerful tool for appraising non-drug interventions in the market
and under development.