Table 1 Description of scenarios
Scenario | Programmatic implementation and evidence | Model implementation |
|---|---|---|
1. Baseline programmatic conditions continued | All 2014 programmatic parameters remain unchanged (including 24 month duration of MDR-TB regimen and 400 treatment places available at any one time being the limiting factor for treatment commencement in 2014) | |
2A. Short-course MDR-TB regimen | Change from standard WHO regimen to short-course regimen [6–9] | Total period of time on treatment for MDR-TB regimens decreases from a mean of 24 months to 10 months (with treatment places remaining capped at 400) |
2B. Short-course MDR-TB regimen with improved outcomes | As for short-course regimen, with improvement in treatment outcomes [6] | Treatment outcomes improve to a treatment success rate of 87.9% (with ratio of deaths to defaults under treatment unchanged), in addition to changes modelled under short-course regimen scenario above |
3. Decreased delays to detection for all forms of TB (first comparator) | Active or intensified case finding halves the period of time to first presentation from baseline value [28, 29] | Time from disease onset to correct identification of patients as having active TB halves (with no change to the proportion correctly identified as to their infecting strain) |
4. Improved MDR-TB treatment outcomes (second comparator) | Social support for all patients on treatment halves the proportion of outcomes resulting in interruption/failure or death [30] | Proportion of patients interrupting/failing or dying on treatment halves (with treatment success proportion increasing to 1 – [1 – previous treatment success proportion] ÷ 2) |
5. Improved MDR-TB identification (third comparator) | Halve the number of health facilities without access to drug-susceptibility testing (e.g. Xpert MTB/RIF), thereby halving the proportion of patients not recognised as MDR-TB at presentation [31, 32] | Proportion of patients with MDR-TB who are incorrectly diagnosed as having DS-TB halves (with correct diagnosis proportion increasing to 1 – [1 – previous correct identification proportion] ÷ 2) |
6. Increased MDR-TB treatment availability (fourth comparator) | Increased resources doubles the number of patients that can be simultaneously treated | Increase number of MDR-TB treatment places available to 800 (with DS-TB and XDR-TB treatment capacity unchanged) |