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Table 1 Decision analysis model parameters related to the natural history, epidemiology, treatment of LTBI and TB

From: Social and behavioral risk reduction strategies for tuberculosis prevention in Canadian Inuit communities: a cost-effectiveness analysis

ESTIMATE PROBABILITY (%) or VALUE (RANGE) REFERENCE
Probabilities (once-time percentages)
 Probability of completing latent TB infection treatment among those who initiate treatment 75.6 [28]
 Probability of diagnosing active disease 90 Assumption
 Probability of spontaneous resolution of untreated TB disease 25 [29]
 Probability of relapse after active TB treatment 1.4 Dynamic modelb,d
 Protective immunity from previous TB disease 55 Dynamic modelb
Probabilities for those without any of the four specific TB risk factors
 Probability of rapid progression following TB infection 0.18/yeara Dynamic modelb
 Probability of reactivation of longstanding latent TB infection to TB disease 0.05/year [30,31,32]
 Probability of dying from untreated TB 7.7/yearc [33]
 Probability of dying from TB during treatment 1.7/yearc [34]
Quality Adjusted Life Years for Latent TB Iinfectuin and active TB
 Utility score for individual with active TB disease (during treatment) 0.85 (0.70–0.90) [35]
 Utility score for individual with active TB disease (before treatment) 0.68 (0.65–0.72) [36]
 Utility score for individual with latent TB infection, (during treatment) 0.97 (0.95–1.00) [36]
 Utility score for individual with latent TB infection (before treatment) 1 Assumptione
  1. aThis value is very low because it applies only to those not exposed to any of the four TB risk factors. Taking a weighted average across the 16 strata gives a rapid progression value of 0.8%/year
  2. bCalibrated using dynamic model, see Additional file 1– section “Calibration details”
  3. cTaking a weighted average of these values over all 16 strata gives values from literature
  4. dAlthough this is calibrated, its initial value was based on the literature: the probability of relapse following active TB treatment started at 1.5% [34, 37]
  5. eIndividuals with latent TB infection are asymptomatic and are assumed to be otherwise healthy