From: Tuberculosis screening of travelers to higher-incidence countries: A cost-effectiveness analysis
 | Base value | Range | Sources |
---|---|---|---|
Annual risk of progression from latent tuberculosis (LTBI) to TB disease | Â | Â | Â |
   Among persons newly infected during travel |  |  |  |
First two years after infection | 0.025 | 0.02 – 0.05 | [33] |
Subsequently | 0.001 | 0.001 – 0.002 | [34] |
   Among persons with LTBI before travel, given |  |  |  |
No underlying radiographic abnormalities [see below] | 0.001 | Â | [34] |
Underlying radiographic abnormalities [see below] | 0.0066 | Â | [34] |
   Reduction in risk afforded by: |  |  |  |
Full 9 months of isoniazid, given drug-sensitive latent infection | 90% | Â | [35] |
<6 months isoniazid | 0% | Â | [36] |
Previous LTBI, among persons who are reinfected during travel | 79% | Â | [37] |
Prevalence of isoniazid resistance | Â | Â | Â |
   Mexico | 0.072 | 0.072 – 0.12 | [38, 39] |
   Dominican Republic | 0.198 | -- | [40] |
   Haiti | 0.159 | -- | [41] |
Active TB | Â | Â | Â |
   Proportion of travelers with active TB symptomatic upon return | 0.27 | 0.11 – 0.44 | [21, 26] |
   Probability of hospitalization given active TB diagnosed after symptoms | 0.8 |  | [42] |
   Probability of hospitalization given active TB diagnosed through screening | 0.5 |  | [21, 22] |
   Probability of completing full anti-TB therapy | 1.0 |  | assumed |
   Risk of major side effect with full anti-TB therapy | 0.051 | 0.01 – 0.1 | [43] |
   Probability of death, given major treatment side effect | 0.015 | 0.001 – 0.032 | [43–45] |
Treatment of latent TB infection | Â | Â | Â |
   Probability of completing 9 months isoniazid | 0.647 | 0.62 – 1 | [10, 46] |
   Probability of major side effect with isoniazid | 0.003 |  | [43–45] |
   Probability of death, given major treatment side effect | 0.015 | 0.001 – 0.032 | [43–45] |
Tuberculin skin testing | Â | Â | Â |
   Probability of boosting, given previous BCG vaccination | 0.25 |  | [17] |
   Specificity for LTBI | 0.875 | - | [17] |
   Sensitivity for LTBI | 0.99 | - | [47, 48] |
   Sensitivity for active TB | 0.88 | - | [48] |
   Probability of loss to follow-up between pre- and post- travel evaluations, for repeat testing strategies | 0.34 |  | [7] |
Probability of abnormal chest X-ray upon return from travel | Â | Â | Â |
   With preexisting LTBI | 0.11 | 0.07 – 0.15 | [33, 34, 49, 50] |
   With LTBI newly acquired during travel | 0 |  | assumed |
   With active TB | 0.95 | 0.9 – 1 | [51, 52] |
Sputum cultures (3) for M. Tuberculosis | Â | Â | Â |
   Specificity | 0.99 |  | [51] |
   Sensitivity | 0.9 |  | [53] |
Costs for TB screening and care in the US (expressed in 2005 US dollars) | Â | Â | Â |
   Initial clinic visit | $68 |  | [54, 25] |
   Tuberculin skin test | $12 |  | [42, 23] |
   Follow-up clinic visit after tuberculin test | $36 |  | [42] |
   Chest radiograph with reading | $36 |  | [42] |
   Isoniazid, 9 months supply | $25 |  | [54] |
   7 outpatient clinic visits during isoniazid treatment | $385 |  | [54] |
   Major adverse reaction to isoniazid | $9,834 |  | [54] |
   3 sputa for AFB smear and culture, after abnormal CXR | $126 |  | [55, 56] |
   Inpatient treatment of active TB disease | $9,061 |  | [57] |
   Outpatient treatment of active TB disease | $2,600 |  | [42] |
   Contact investigation and management, per active TB case (identified via screening) | $4,483 |  | [42, 24] |