From: Counting the lives saved by DOTS in India: a model-based approach
Parameter name | Symbol | Value | Note/source |
---|---|---|---|
Average number of infections per drug-susceptible (DS) TB case per year | β | 10.7 [5.8–13.6] | Estimated |
Average number of infections per MDR-TB case per year | β mdr | 2.00 [1.62–2.62] | Estimated |
Per care seeking attempt, probability of seeking care in the public sector (following RNTCP scale-up) | p max | 0.34 [0.25–0.58] | Estimated to get reported notifications from 1997–2015 |
Proportion of MDR-TB cases whose drug resistance is recognized at the point of TB diagnosis and who start appropriate treatment | q max | 0.07 [0.06–0.09] | Estimated to get reported notifications from 2007–2015 |
Reduction in force of infection owing to previous infection | C | 0.5 | Assumed |
Proportion of infections undergoing ‘rapid’ progression | k | 0.15 | Vynnycky and Fine, 1997 [42] |
Rate of breakdown from remote infection to active disease | h | 0.001 y-1 | Horsburgh et al., 2010 [43] |
Rate corresponding to the delay from the start of symptoms to the initiation of treatment (whether in public or private sector) | r | 3.29 y-1 [0.83–5.70] | Estimated |
Mean duration of first-line treatment | \( {\uptau}_{\mathrm{FL}} \) | 2 y-1 | Corresponding to 6Â months of treatment duration |
Rate of default from non-RNTCP treatment | d RNTCP | 1.06 y-1 | Uplekar et al. 1998 [29] |
Rate of default from RNTCP treatment | d non-RNTCP | 0.049 y-1 | Corresponds to 4.8% default in RNTCP (TB India, 2015 [34]) (averaged over smear-positive, smear-negative and extrapulmonary TB) |
Rate of repeat care seeking after recurrence or failure | w | 4 y-1 | Corresponds to 3Â months of delay period |
Annual recurrence rate | \( \uprho \) | 0.003 y-1 | Corresponds to lifetime recurrence risk of 17% (Sun et al., 2013 [44]) |
Rate of primary MDR acquisition from patient treated under RNTCP | m | 0.02 y-1 | TB India, 2015 [34] |
Mean duration of second-line treatment | \( {\uptau}_{\mathrm{SL}} \) | 0.5 y-1 | Corresponding to 2Â years of treatment duration |
Spontaneous cure rate | \( \upsigma \) | 0.166 y-1 | Corresponds to 50% spontaneous cure in 3Â years alongside with TB mortality (Tiemersma et al., 2011 [26]) |
Proportion cure of drug-susceptible (DS)-TB in RNTCP after first-line treatment | α pub | 0.87 | TB India, 2015 [34] |
Proportion cure of DS-TB in non-RNTCP after first-line treatment | α prv | 0.51 | Uplekar et al., 1998 [29] |
Proportion cure of MDR-TB in RNTCP after first-line treatment (excluding self-cure) | α’ pub | 0.24 | TB India, 2015 [34] |
Proportion cure of MDR-TB in non-RNTCP after first-line treatment | α’ prv | 0 | Assumed |
Proportion cure of MDR-TB with second-line treatment (excluding self-cure) | α’ pub2 | 0.48 | TB India, 2014 [45] |
Per-capita mortality hazard before diagnosis | μ UTB | 0.086 (95% CI 0.075–0.11) y-1 | See Additional file 1 |
Mortality hazard during RNTCP treatment | μ RNTCP | 0.076 (95% CI 0.069–0.095) y-1 | See Additional file 1 |
Mortality hazard during non-RNTCP treatment | μ non-RNTCP | 0.27 (95% CI 0.22–0.33) y-1 | See Additional file 1 |
Mortality hazard following default and treatment failure | μ B | 0.28 (95% CI 0.22–0.36) y-1 | See Additional file 1 |