Fig 1.
Simplified algorithms of no screening and three screening strategies.
*Those with QFT-GIT negative results follow no screening strategy.
Fig 2.
Simplified decision analytic process based on Markov model.
Model states in three screening strategies for subsequent years where screenings do not occur are identical to no screening strategy (Clone 1: patient-initiated pathway). In decision analysis, decision node represents the selection of alternative strategies, and chance node represents the selection of probabilities. Markov node indicates the start of Markov model and represents the selection of health states in a number of Markov cycles.
Table 1.
Model parameters of probabilities.
Table 2.
Model parameters of costs (USD, 1 USD = 7.8 HKD).
Table 3.
Model parameters of utility.
Table 4.
Cost-effectiveness of four strategies.
Table 5.
Optimal strategy according to the willingness-to-pay threshold (US$/QALYs) in one way sensitivity analysis.
Fig 3.
Incremental cost-effectiveness ratio of LTBI/TB screening vs. TB screening (Xpert) in 1,000 iterations of Monte Carlo simulation.
The ellipse represents 95% confidence points. The diagonal line represents ICER at a WTP threshold of US$50,000/QALY. Points to the right of the diagonal line represent the iterations where LTBI/TB screening to be cost-effective.
Fig 4.
Cost-effectiveness acceptability curve for four strategies in Monte Carlo simulation.